drivers/usb/gadget/function/f_fs.c

   1 /*
   2  * f_fs.c -- user mode file system API for USB composite function controllers
   3  *
   4  * Copyright (C) 2010 Samsung Electronics
   5  * Author: Michal Nazarewicz <mina86@mina86.com>
   6  *
   7  * Based on inode.c (GadgetFS) which was:
   8  * Copyright (C) 2003-2004 David Brownell
   9  * Copyright (C) 2003 Agilent Technologies
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2 of the License, or
  14  * (at your option) any later version.
  15  */
  16
  17
  18 /* #define DEBUG */
  19 /* #define VERBOSE_DEBUG */
  20
  21 #include <linux/blkdev.h>
  22 #include <linux/pagemap.h>
  23 #include <linux/export.h>
  24 #include <linux/hid.h>
  25 #include <linux/module.h>
  26 #include <linux/uio.h>
  27 #include <asm/unaligned.h>
  28
  29 #include <linux/usb/composite.h>
  30 #include <linux/usb/functionfs.h>
  31
  32 #include <linux/aio.h>
  33 #include <linux/mmu_context.h>
  34 #include <linux/poll.h>
  35 #include <linux/eventfd.h>
  36
  37 #include "u_fs.h"
  38 #include "u_f.h"
  39 #include "u_os_desc.h"
  40 #include "configfs.h"
  41
  42 #define FUNCTIONFS_MAGIC        0xa647361 /* Chosen by a honest dice roll ;) */
  43
  44 /* Reference counter handling */
  45 static void ffs_data_get(struct ffs_data *ffs);
  46 static void ffs_data_put(struct ffs_data *ffs);
  47 /* Creates new ffs_data object. */
  48 static struct ffs_data *__must_check ffs_data_new(void) __attribute__((malloc));
  49
  50 /* Opened counter handling. */
  51 static void ffs_data_opened(struct ffs_data *ffs);
  52 static void ffs_data_closed(struct ffs_data *ffs);
  53
  54 /* Called with ffs->mutex held; take over ownership of data. */
  55 static int __must_check
  56 __ffs_data_got_descs(struct ffs_data *ffs, char *data, size_t len);
  57 static int __must_check
  58 __ffs_data_got_strings(struct ffs_data *ffs, char *data, size_t len);
  59
  60
  61 /* The function structure ***************************************************/
  62
  63 struct ffs_ep;
  64
  65 struct ffs_function {
  66         struct usb_configuration        *conf;
  67         struct usb_gadget               *gadget;
  68         struct ffs_data                 *ffs;
  69
  70         struct ffs_ep                   *eps;
  71         u8                              eps_revmap[16];
  72         short                           *interfaces_nums;
  73
  74         struct usb_function             function;
  75 };
  76
  77
  78 static struct ffs_function *ffs_func_from_usb(struct usb_function *f)
  79 {
  80         return container_of(f, struct ffs_function, function);
  81 }
  82
  83
  84 static inline enum ffs_setup_state
  85 ffs_setup_state_clear_cancelled(struct ffs_data *ffs)
  86 {
  87         return (enum ffs_setup_state)
  88                 cmpxchg(&ffs->setup_state, FFS_SETUP_CANCELLED, FFS_NO_SETUP);
  89 }
  90
  91
  92 static void ffs_func_eps_disable(struct ffs_function *func);
  93 static int __must_check ffs_func_eps_enable(struct ffs_function *func);
  94
  95 static int ffs_func_bind(struct usb_configuration *,
  96                          struct usb_function *);
  97 static int ffs_func_set_alt(struct usb_function *, unsigned, unsigned);
  98 static void ffs_func_disable(struct usb_function *);
  99 static int ffs_func_setup(struct usb_function *,
 100                           const struct usb_ctrlrequest *);
 101 static void ffs_func_suspend(struct usb_function *);
 102 static void ffs_func_resume(struct usb_function *);
 103
 104
 105 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num);
 106 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf);
 107
 108
 109 /* The endpoints structures *************************************************/
 110
 111 struct ffs_ep {
 112         struct usb_ep                   *ep;    /* P: ffs->eps_lock */
 113         struct usb_request              *req;   /* P: epfile->mutex */
 114
 115         /* [0]: full speed, [1]: high speed, [2]: super speed */
 116         struct usb_endpoint_descriptor  *descs[3];
 117
 118         u8                              num;
 119
 120         int                             status; /* P: epfile->mutex */
 121 };
 122
 123 struct ffs_epfile {
 124         /* Protects ep->ep and ep->req. */
 125         struct mutex                    mutex;
 126         wait_queue_head_t               wait;
 127
 128         struct ffs_data                 *ffs;
 129         struct ffs_ep                   *ep;    /* P: ffs->eps_lock */
 130
 131         struct dentry                   *dentry;
 132
 133         /*
 134          * Buffer for holding data from partial reads which may happen since
 135          * we’re rounding user read requests to a multiple of a max packet size.
 136          */
 137         struct ffs_buffer               *read_buffer;   /* P: epfile->mutex */
 138
 139         char                            name[5];
 140
 141         unsigned char                   in;     /* P: ffs->eps_lock */
 142         unsigned char                   isoc;   /* P: ffs->eps_lock */
 143
 144         unsigned char                   _pad;
 145 };
 146
 147 struct ffs_buffer {
 148         size_t length;
 149         char *data;
 150         char storage[];
 151 };
 152
 153 /*  ffs_io_data structure ***************************************************/
 154
 155 struct ffs_io_data {
 156         bool aio;
 157         bool read;
 158
 159         struct kiocb *kiocb;
 160         struct iov_iter data;
 161         const void *to_free;
 162         char *buf;
 163
 164         struct mm_struct *mm;
 165         struct work_struct work;
 166
 167         struct usb_ep *ep;
 168         struct usb_request *req;
 169
 170         struct ffs_data *ffs;
 171 };
 172
 173 struct ffs_desc_helper {
 174         struct ffs_data *ffs;
 175         unsigned interfaces_count;
 176         unsigned eps_count;
 177 };
 178
 179 static int  __must_check ffs_epfiles_create(struct ffs_data *ffs);
 180 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count);
 181
 182 static struct dentry *
 183 ffs_sb_create_file(struct super_block *sb, const char *name, void *data,
 184                    const struct file_operations *fops);
 185
 186 /* Devices management *******************************************************/
 187
 188 DEFINE_MUTEX(ffs_lock);
 189 EXPORT_SYMBOL_GPL(ffs_lock);
 190
 191 static struct ffs_dev *_ffs_find_dev(const char *name);
 192 static struct ffs_dev *_ffs_alloc_dev(void);
 193 static int _ffs_name_dev(struct ffs_dev *dev, const char *name);
 194 static void _ffs_free_dev(struct ffs_dev *dev);
 195 static void *ffs_acquire_dev(const char *dev_name);
 196 static void ffs_release_dev(struct ffs_data *ffs_data);
 197 static int ffs_ready(struct ffs_data *ffs);
 198 static void ffs_closed(struct ffs_data *ffs);
 199
 200 /* Misc helper functions ****************************************************/
 201
 202 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
 203         __attribute__((warn_unused_result, nonnull));
 204 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
 205         __attribute__((warn_unused_result, nonnull));
 206
 207
 208 /* Control file aka ep0 *****************************************************/
 209
 210 static void ffs_ep0_complete(struct usb_ep *ep, struct usb_request *req)
 211 {
 212         struct ffs_data *ffs = req->context;
 213
 214         complete_all(&ffs->ep0req_completion);
 215 }
 216
 217 static int __ffs_ep0_queue_wait(struct ffs_data *ffs, char *data, size_t len)
 218 {
 219         struct usb_request *req = ffs->ep0req;
 220         int ret;
 221
 222         req->zero     = len < le16_to_cpu(ffs->ev.setup.wLength);
 223
 224         spin_unlock_irq(&ffs->ev.waitq.lock);
 225
 226         req->buf      = data;
 227         req->length   = len;
 228
 229         /*
 230          * UDC layer requires to provide a buffer even for ZLP, but should
 231          * not use it at all. Let's provide some poisoned pointer to catch
 232          * possible bug in the driver.
 233          */
 234         if (req->buf == NULL)
 235                 req->buf = (void *)0xDEADBABE;
 236
 237         reinit_completion(&ffs->ep0req_completion);
 238
 239         ret = usb_ep_queue(ffs->gadget->ep0, req, GFP_ATOMIC);
 240         if (unlikely(ret < 0))
 241                 return ret;
 242
 243         ret = wait_for_completion_interruptible(&ffs->ep0req_completion);
 244         if (unlikely(ret)) {
 245                 usb_ep_dequeue(ffs->gadget->ep0, req);
 246                 return -EINTR;
 247         }
 248
 249         ffs->setup_state = FFS_NO_SETUP;
 250         return req->status ? req->status : req->actual;
 251 }
 252
 253 static int __ffs_ep0_stall(struct ffs_data *ffs)
 254 {
 255         if (ffs->ev.can_stall) {
 256                 pr_vdebug("ep0 stall\n");
 257                 usb_ep_set_halt(ffs->gadget->ep0);
 258                 ffs->setup_state = FFS_NO_SETUP;
 259                 return -EL2HLT;
 260         } else {
 261                 pr_debug("bogus ep0 stall!\n");
 262                 return -ESRCH;
 263         }
 264 }
 265
 266 static ssize_t ffs_ep0_write(struct file *file, const char __user *buf,
 267                              size_t len, loff_t *ptr)
 268 {
 269         struct ffs_data *ffs = file->private_data;
 270         ssize_t ret;
 271         char *data;
 272
 273         ENTER();
 274
 275         /* Fast check if setup was canceled */
 276         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
 277                 return -EIDRM;
 278
 279         /* Acquire mutex */
 280         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 281         if (unlikely(ret < 0))
 282                 return ret;
 283
 284         /* Check state */
 285         switch (ffs->state) {
 286         case FFS_READ_DESCRIPTORS:
 287         case FFS_READ_STRINGS:
 288                 /* Copy data */
 289                 if (unlikely(len < 16)) {
 290                         ret = -EINVAL;
 291                         break;
 292                 }
 293
 294                 data = ffs_prepare_buffer(buf, len);
 295                 if (IS_ERR(data)) {
 296                         ret = PTR_ERR(data);
 297                         break;
 298                 }
 299
 300                 /* Handle data */
 301                 if (ffs->state == FFS_READ_DESCRIPTORS) {
 302                         pr_info("read descriptors\n");
 303                         ret = __ffs_data_got_descs(ffs, data, len);
 304                         if (unlikely(ret < 0))
 305                                 break;
 306
 307                         ffs->state = FFS_READ_STRINGS;
 308                         ret = len;
 309                 } else {
 310                         pr_info("read strings\n");
 311                         ret = __ffs_data_got_strings(ffs, data, len);
 312                         if (unlikely(ret < 0))
 313                                 break;
 314
 315                         ret = ffs_epfiles_create(ffs);
 316                         if (unlikely(ret)) {
 317                                 ffs->state = FFS_CLOSING;
 318                                 break;
 319                         }
 320
 321                         ffs->state = FFS_ACTIVE;
 322                         mutex_unlock(&ffs->mutex);
 323
 324                         ret = ffs_ready(ffs);
 325                         if (unlikely(ret < 0)) {
 326                                 ffs->state = FFS_CLOSING;
 327                                 return ret;
 328                         }
 329
 330                         return len;
 331                 }
 332                 break;
 333
 334         case FFS_ACTIVE:
 335                 data = NULL;
 336                 /*
 337                  * We're called from user space, we can use _irq
 338                  * rather then _irqsave
 339                  */
 340                 spin_lock_irq(&ffs->ev.waitq.lock);
 341                 switch (ffs_setup_state_clear_cancelled(ffs)) {
 342                 case FFS_SETUP_CANCELLED:
 343                         ret = -EIDRM;
 344                         goto done_spin;
 345
 346                 case FFS_NO_SETUP:
 347                         ret = -ESRCH;
 348                         goto done_spin;
 349
 350                 case FFS_SETUP_PENDING:
 351                         break;
 352                 }
 353
 354                 /* FFS_SETUP_PENDING */
 355                 if (!(ffs->ev.setup.bRequestType & USB_DIR_IN)) {
 356                         spin_unlock_irq(&ffs->ev.waitq.lock);
 357                         ret = __ffs_ep0_stall(ffs);
 358                         break;
 359                 }
 360
 361                 /* FFS_SETUP_PENDING and not stall */
 362                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 363
 364                 spin_unlock_irq(&ffs->ev.waitq.lock);
 365
 366                 data = ffs_prepare_buffer(buf, len);
 367                 if (IS_ERR(data)) {
 368                         ret = PTR_ERR(data);
 369                         break;
 370                 }
 371
 372                 spin_lock_irq(&ffs->ev.waitq.lock);
 373
 374                 /*
 375                  * We are guaranteed to be still in FFS_ACTIVE state
 376                  * but the state of setup could have changed from
 377                  * FFS_SETUP_PENDING to FFS_SETUP_CANCELLED so we need
 378                  * to check for that.  If that happened we copied data
 379                  * from user space in vain but it's unlikely.
 380                  *
 381                  * For sure we are not in FFS_NO_SETUP since this is
 382                  * the only place FFS_SETUP_PENDING -> FFS_NO_SETUP
 383                  * transition can be performed and it's protected by
 384                  * mutex.
 385                  */
 386                 if (ffs_setup_state_clear_cancelled(ffs) ==
 387                     FFS_SETUP_CANCELLED) {
 388                         ret = -EIDRM;
 389 done_spin:
 390                         spin_unlock_irq(&ffs->ev.waitq.lock);
 391                 } else {
 392                         /* unlocks spinlock */
 393                         ret = __ffs_ep0_queue_wait(ffs, data, len);
 394                 }
 395                 kfree(data);
 396                 break;
 397
 398         default:
 399                 ret = -EBADFD;
 400                 break;
 401         }
 402
 403         mutex_unlock(&ffs->mutex);
 404         return ret;
 405 }
 406
 407 /* Called with ffs->ev.waitq.lock and ffs->mutex held, both released on exit. */
 408 static ssize_t __ffs_ep0_read_events(struct ffs_data *ffs, char __user *buf,
 409                                      size_t n)
 410 {
 411         /*
 412          * n cannot be bigger than ffs->ev.count, which cannot be bigger than
 413          * size of ffs->ev.types array (which is four) so that's how much space
 414          * we reserve.
 415          */
 416         struct usb_functionfs_event events[ARRAY_SIZE(ffs->ev.types)];
 417         const size_t size = n * sizeof *events;
 418         unsigned i = 0;
 419
 420         memset(events, 0, size);
 421
 422         do {
 423                 events[i].type = ffs->ev.types[i];
 424                 if (events[i].type == FUNCTIONFS_SETUP) {
 425                         events[i].u.setup = ffs->ev.setup;
 426                         ffs->setup_state = FFS_SETUP_PENDING;
 427                 }
 428         } while (++i < n);
 429
 430         ffs->ev.count -= n;
 431         if (ffs->ev.count)
 432                 memmove(ffs->ev.types, ffs->ev.types + n,
 433                         ffs->ev.count * sizeof *ffs->ev.types);
 434
 435         spin_unlock_irq(&ffs->ev.waitq.lock);
 436         mutex_unlock(&ffs->mutex);
 437
 438         return unlikely(copy_to_user(buf, events, size)) ? -EFAULT : size;
 439 }
 440
 441 static ssize_t ffs_ep0_read(struct file *file, char __user *buf,
 442                             size_t len, loff_t *ptr)
 443 {
 444         struct ffs_data *ffs = file->private_data;
 445         char *data = NULL;
 446         size_t n;
 447         int ret;
 448
 449         ENTER();
 450
 451         /* Fast check if setup was canceled */
 452         if (ffs_setup_state_clear_cancelled(ffs) == FFS_SETUP_CANCELLED)
 453                 return -EIDRM;
 454
 455         /* Acquire mutex */
 456         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 457         if (unlikely(ret < 0))
 458                 return ret;
 459
 460         /* Check state */
 461         if (ffs->state != FFS_ACTIVE) {
 462                 ret = -EBADFD;
 463                 goto done_mutex;
 464         }
 465
 466         /*
 467          * We're called from user space, we can use _irq rather then
 468          * _irqsave
 469          */
 470         spin_lock_irq(&ffs->ev.waitq.lock);
 471
 472         switch (ffs_setup_state_clear_cancelled(ffs)) {
 473         case FFS_SETUP_CANCELLED:
 474                 ret = -EIDRM;
 475                 break;
 476
 477         case FFS_NO_SETUP:
 478                 n = len / sizeof(struct usb_functionfs_event);
 479                 if (unlikely(!n)) {
 480                         ret = -EINVAL;
 481                         break;
 482                 }
 483
 484                 if ((file->f_flags & O_NONBLOCK) && !ffs->ev.count) {
 485                         ret = -EAGAIN;
 486                         break;
 487                 }
 488
 489                 if (wait_event_interruptible_exclusive_locked_irq(ffs->ev.waitq,
 490                                                         ffs->ev.count)) {
 491                         ret = -EINTR;
 492                         break;
 493                 }
 494
 495                 return __ffs_ep0_read_events(ffs, buf,
 496                                              min(n, (size_t)ffs->ev.count));
 497
 498         case FFS_SETUP_PENDING:
 499                 if (ffs->ev.setup.bRequestType & USB_DIR_IN) {
 500                         spin_unlock_irq(&ffs->ev.waitq.lock);
 501                         ret = __ffs_ep0_stall(ffs);
 502                         goto done_mutex;
 503                 }
 504
 505                 len = min(len, (size_t)le16_to_cpu(ffs->ev.setup.wLength));
 506
 507                 spin_unlock_irq(&ffs->ev.waitq.lock);
 508
 509                 if (likely(len)) {
 510                         data = kmalloc(len, GFP_KERNEL);
 511                         if (unlikely(!data)) {
 512                                 ret = -ENOMEM;
 513                                 goto done_mutex;
 514                         }
 515                 }
 516
 517                 spin_lock_irq(&ffs->ev.waitq.lock);
 518
 519                 /* See ffs_ep0_write() */
 520                 if (ffs_setup_state_clear_cancelled(ffs) ==
 521                     FFS_SETUP_CANCELLED) {
 522                         ret = -EIDRM;
 523                         break;
 524                 }
 525
 526                 /* unlocks spinlock */
 527                 ret = __ffs_ep0_queue_wait(ffs, data, len);
 528                 if (likely(ret > 0) && unlikely(copy_to_user(buf, data, len)))
 529                         ret = -EFAULT;
 530                 goto done_mutex;
 531
 532         default:
 533                 ret = -EBADFD;
 534                 break;
 535         }
 536
 537         spin_unlock_irq(&ffs->ev.waitq.lock);
 538 done_mutex:
 539         mutex_unlock(&ffs->mutex);
 540         kfree(data);
 541         return ret;
 542 }
 543
 544 static int ffs_ep0_open(struct inode *inode, struct file *file)
 545 {
 546         struct ffs_data *ffs = inode->i_private;
 547
 548         ENTER();
 549
 550         if (unlikely(ffs->state == FFS_CLOSING))
 551                 return -EBUSY;
 552
 553         file->private_data = ffs;
 554         ffs_data_opened(ffs);
 555
 556         return 0;
 557 }
 558
 559 static int ffs_ep0_release(struct inode *inode, struct file *file)
 560 {
 561         struct ffs_data *ffs = file->private_data;
 562
 563         ENTER();
 564
 565         ffs_data_closed(ffs);
 566
 567         return 0;
 568 }
 569
 570 static long ffs_ep0_ioctl(struct file *file, unsigned code, unsigned long value)
 571 {
 572         struct ffs_data *ffs = file->private_data;
 573         struct usb_gadget *gadget = ffs->gadget;
 574         long ret;
 575
 576         ENTER();
 577
 578         if (code == FUNCTIONFS_INTERFACE_REVMAP) {
 579                 struct ffs_function *func = ffs->func;
 580                 ret = func ? ffs_func_revmap_intf(func, value) : -ENODEV;
 581         } else if (gadget && gadget->ops->ioctl) {
 582                 ret = gadget->ops->ioctl(gadget, code, value);
 583         } else {
 584                 ret = -ENOTTY;
 585         }
 586
 587         return ret;
 588 }
 589
 590 static unsigned int ffs_ep0_poll(struct file *file, poll_table *wait)
 591 {
 592         struct ffs_data *ffs = file->private_data;
 593         unsigned int mask = POLLWRNORM;
 594         int ret;
 595
 596         poll_wait(file, &ffs->ev.waitq, wait);
 597
 598         ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
 599         if (unlikely(ret < 0))
 600                 return mask;
 601
 602         switch (ffs->state) {
 603         case FFS_READ_DESCRIPTORS:
 604         case FFS_READ_STRINGS:
 605                 mask |= POLLOUT;
 606                 break;
 607
 608         case FFS_ACTIVE:
 609                 switch (ffs->setup_state) {
 610                 case FFS_NO_SETUP:
 611                         if (ffs->ev.count)
 612                                 mask |= POLLIN;
 613                         break;
 614
 615                 case FFS_SETUP_PENDING:
 616                 case FFS_SETUP_CANCELLED:
 617                         mask |= (POLLIN | POLLOUT);
 618                         break;
 619                 }
 620         case FFS_CLOSING:
 621                 break;
 622         case FFS_DEACTIVATED:
 623                 break;
 624         }
 625
 626         mutex_unlock(&ffs->mutex);
 627
 628         return mask;
 629 }
 630
 631 static const struct file_operations ffs_ep0_operations = {
 632         .llseek =       no_llseek,
 633
 634         .open =         ffs_ep0_open,
 635         .write =        ffs_ep0_write,
 636         .read =         ffs_ep0_read,
 637         .release =      ffs_ep0_release,
 638         .unlocked_ioctl =       ffs_ep0_ioctl,
 639         .poll =         ffs_ep0_poll,
 640 };
 641
 642
 643 /* "Normal" endpoints operations ********************************************/
 644
 645 static void ffs_epfile_io_complete(struct usb_ep *_ep, struct usb_request *req)
 646 {
 647         ENTER();
 648         if (likely(req->context)) {
 649                 struct ffs_ep *ep = _ep->driver_data;
 650                 ep->status = req->status ? req->status : req->actual;
 651                 complete(req->context);
 652         }
 653 }
 654
 655 static ssize_t ffs_copy_to_iter(void *data, int data_len, struct iov_iter *iter)
 656 {
 657         ssize_t ret = copy_to_iter(data, data_len, iter);
 658         if (likely(ret == data_len))
 659                 return ret;
 660
 661         if (unlikely(iov_iter_count(iter)))
 662                 return -EFAULT;
 663
 664         /*
 665          * Dear user space developer!
 666          *
 667          * TL;DR: To stop getting below error message in your kernel log, change
 668          * user space code using functionfs to align read buffers to a max
 669          * packet size.
 670          *
 671          * Some UDCs (e.g. dwc3) require request sizes to be a multiple of a max
 672          * packet size.  When unaligned buffer is passed to functionfs, it
 673          * internally uses a larger, aligned buffer so that such UDCs are happy.
 674          *
 675          * Unfortunately, this means that host may send more data than was
 676          * requested in read(2) system call.  f_fs doesn’t know what to do with
 677          * that excess data so it simply drops it.
 678          *
 679          * Was the buffer aligned in the first place, no such problem would
 680          * happen.
 681          *
 682          * Data may be dropped only in AIO reads.  Synchronous reads are handled
 683          * by splitting a request into multiple parts.  This splitting may still
 684          * be a problem though so it’s likely best to align the buffer
 685          * regardless of it being AIO or not..
 686          *
 687          * This only affects OUT endpoints, i.e. reading data with a read(2),
 688          * aio_read(2) etc. system calls.  Writing data to an IN endpoint is not
 689          * affected.
 690          */
 691         pr_err("functionfs read size %d > requested size %zd, dropping excess data. "
 692                "Align read buffer size to max packet size to avoid the problem.\n",
 693                data_len, ret);
 694
 695         return ret;
 696 }
 697
 698 static void ffs_user_copy_worker(struct work_struct *work)
 699 {
 700         struct ffs_io_data *io_data = container_of(work, struct ffs_io_data,
 701                                                    work);
 702         int ret = io_data->req->status ? io_data->req->status :
 703                                          io_data->req->actual;
 704         bool kiocb_has_eventfd = io_data->kiocb->ki_flags & IOCB_EVENTFD;
 705
 706         if (io_data->read && ret > 0) {
 707                 use_mm(io_data->mm);
 708                 ret = ffs_copy_to_iter(io_data->buf, ret, &io_data->data);
 709                 unuse_mm(io_data->mm);
 710         }
 711
 712         io_data->kiocb->ki_complete(io_data->kiocb, ret, ret);
 713
 714         if (io_data->ffs->ffs_eventfd && !kiocb_has_eventfd)
 715                 eventfd_signal(io_data->ffs->ffs_eventfd, 1);
 716
 717         usb_ep_free_request(io_data->ep, io_data->req);
 718
 719         if (io_data->read)
 720                 kfree(io_data->to_free);
 721         kfree(io_data->buf);
 722         kfree(io_data);
 723 }
 724
 725 static void ffs_epfile_async_io_complete(struct usb_ep *_ep,
 726                                          struct usb_request *req)
 727 {
 728         struct ffs_io_data *io_data = req->context;
 729
 730         ENTER();
 731
 732         INIT_WORK(&io_data->work, ffs_user_copy_worker);
 733         schedule_work(&io_data->work);
 734 }
 735
 736 /* Assumes epfile->mutex is held. */
 737 static ssize_t __ffs_epfile_read_buffered(struct ffs_epfile *epfile,
 738                                           struct iov_iter *iter)
 739 {
 740         struct ffs_buffer *buf = epfile->read_buffer;
 741         ssize_t ret;
 742         if (!buf)
 743                 return 0;
 744
 745         ret = copy_to_iter(buf->data, buf->length, iter);
 746         if (buf->length == ret) {
 747                 kfree(buf);
 748                 epfile->read_buffer = NULL;
 749         } else if (unlikely(iov_iter_count(iter))) {
 750                 ret = -EFAULT;
 751         } else {
 752                 buf->length -= ret;
 753                 buf->data += ret;
 754         }
 755         return ret;
 756 }
 757
 758 /* Assumes epfile->mutex is held. */
 759 static ssize_t __ffs_epfile_read_data(struct ffs_epfile *epfile,
 760                                       void *data, int data_len,
 761                                       struct iov_iter *iter)
 762 {
 763         struct ffs_buffer *buf;
 764
 765         ssize_t ret = copy_to_iter(data, data_len, iter);
 766         if (likely(data_len == ret))
 767                 return ret;
 768
 769         if (unlikely(iov_iter_count(iter)))
 770                 return -EFAULT;
 771
 772         /* See ffs_copy_to_iter for more context. */
 773         pr_warn("functionfs read size %d > requested size %zd, splitting request into multiple reads.",
 774                 data_len, ret);
 775
 776         data_len -= ret;
 777         buf = kmalloc(sizeof(*buf) + data_len, GFP_KERNEL);
 778         if (!buf)
 779                 return -ENOMEM;
 780         buf->length = data_len;
 781         buf->data = buf->storage;
 782         memcpy(buf->storage, data + ret, data_len);
 783         epfile->read_buffer = buf;
 784
 785         return ret;
 786 }
 787
 788 static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
 789 {
 790         struct ffs_epfile *epfile = file->private_data;
 791         struct usb_request *req;
 792         struct ffs_ep *ep;
 793         char *data = NULL;
 794         ssize_t ret, data_len = -EINVAL;
 795         int halt;
 796
 797         /* Are we still active? */
 798         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
 799                 return -ENODEV;
 800
 801         /* Wait for endpoint to be enabled */
 802         ep = epfile->ep;
 803         if (!ep) {
 804                 if (file->f_flags & O_NONBLOCK)
 805                         return -EAGAIN;
 806
 807                 ret = wait_event_interruptible(epfile->wait, (ep = epfile->ep));
 808                 if (ret)
 809                         return -EINTR;
 810         }
 811
 812         /* Do we halt? */
 813         halt = (!io_data->read == !epfile->in);
 814         if (halt && epfile->isoc)
 815                 return -EINVAL;
 816
 817         /* We will be using request and read_buffer */
 818         ret = ffs_mutex_lock(&epfile->mutex, file->f_flags & O_NONBLOCK);
 819         if (unlikely(ret))
 820                 goto error;
 821
 822         /* Allocate & copy */
 823         if (!halt) {
 824                 struct usb_gadget *gadget;
 825
 826                 /*
 827                  * Do we have buffered data from previous partial read?  Check
 828                  * that for synchronous case only because we do not have
 829                  * facility to ‘wake up’ a pending asynchronous read and push
 830                  * buffered data to it which we would need to make things behave
 831                  * consistently.
 832                  */
 833                 if (!io_data->aio && io_data->read) {
 834                         ret = __ffs_epfile_read_buffered(epfile, &io_data->data);
 835                         if (ret)
 836                                 goto error_mutex;
 837                 }
 838
 839                 /*
 840                  * if we _do_ wait above, the epfile->ffs->gadget might be NULL
 841                  * before the waiting completes, so do not assign to 'gadget'
 842                  * earlier
 843                  */
 844                 gadget = epfile->ffs->gadget;
 845
 846                 spin_lock_irq(&epfile->ffs->eps_lock);
 847                 /* In the meantime, endpoint got disabled or changed. */
 848                 if (epfile->ep != ep) {
 849                         ret = -ESHUTDOWN;
 850                         goto error_lock;
 851                 }
 852                 data_len = iov_iter_count(&io_data->data);
 853                 /*
 854                  * Controller may require buffer size to be aligned to
 855                  * maxpacketsize of an out endpoint.
 856                  */
 857                 if (io_data->read)
 858                         data_len = usb_ep_align_maybe(gadget, ep->ep, data_len);
 859                 spin_unlock_irq(&epfile->ffs->eps_lock);
 860
 861                 data = kmalloc(data_len, GFP_KERNEL);
 862                 if (unlikely(!data)) {
 863                         ret = -ENOMEM;
 864                         goto error_mutex;
 865                 }
 866                 if (!io_data->read &&
 867                     copy_from_iter(data, data_len, &io_data->data) != data_len) {
 868                         ret = -EFAULT;
 869                         goto error_mutex;
 870                 }
 871         }
 872
 873         spin_lock_irq(&epfile->ffs->eps_lock);
 874
 875         if (epfile->ep != ep) {
 876                 /* In the meantime, endpoint got disabled or changed. */
 877                 ret = -ESHUTDOWN;
 878         } else if (halt) {
 879                 /* Halt */
 880                 if (likely(epfile->ep == ep) && !WARN_ON(!ep->ep))
 881                         usb_ep_set_halt(ep->ep);
 882                 ret = -EBADMSG;
 883         } else if (unlikely(data_len == -EINVAL)) {
 884                 /*
 885                  * Sanity Check: even though data_len can't be used
 886                  * uninitialized at the time I write this comment, some
 887                  * compilers complain about this situation.
 888                  * In order to keep the code clean from warnings, data_len is
 889                  * being initialized to -EINVAL during its declaration, which
 890                  * means we can't rely on compiler anymore to warn no future
 891                  * changes won't result in data_len being used uninitialized.
 892                  * For such reason, we're adding this redundant sanity check
 893                  * here.
 894                  */
 895                 WARN(1, "%s: data_len == -EINVAL\n", __func__);
 896                 ret = -EINVAL;
 897         } else if (!io_data->aio) {
 898                 DECLARE_COMPLETION_ONSTACK(done);
 899                 bool interrupted = false;
 900
 901                 req = ep->req;
 902                 req->buf      = data;
 903                 req->length   = data_len;
 904
 905                 req->context  = &done;
 906                 req->complete = ffs_epfile_io_complete;
 907
 908                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
 909                 if (unlikely(ret < 0))
 910                         goto error_lock;
 911
 912                 spin_unlock_irq(&epfile->ffs->eps_lock);
 913
 914                 if (unlikely(wait_for_completion_interruptible(&done))) {
 915                         /*
 916                          * To avoid race condition with ffs_epfile_io_complete,
 917                          * dequeue the request first then check
 918                          * status. usb_ep_dequeue API should guarantee no race
 919                          * condition with req->complete callback.
 920                          */
 921                         usb_ep_dequeue(ep->ep, req);
 922                         interrupted = ep->status < 0;
 923                 }
 924
 925                 if (interrupted)
 926                         ret = -EINTR;
 927                 else if (io_data->read && ep->status > 0)
 928                         ret = __ffs_epfile_read_data(epfile, data, ep->status,
 929                                                      &io_data->data);
 930                 else
 931                         ret = ep->status;
 932                 goto error_mutex;
 933         } else if (!(req = usb_ep_alloc_request(ep->ep, GFP_KERNEL))) {
 934                 ret = -ENOMEM;
 935         } else {
 936                 req->buf      = data;
 937                 req->length   = data_len;
 938
 939                 io_data->buf = data;
 940                 io_data->ep = ep->ep;
 941                 io_data->req = req;
 942                 io_data->ffs = epfile->ffs;
 943
 944                 req->context  = io_data;
 945                 req->complete = ffs_epfile_async_io_complete;
 946
 947                 ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
 948                 if (unlikely(ret)) {
 949                         usb_ep_free_request(ep->ep, req);
 950                         goto error_lock;
 951                 }
 952
 953                 ret = -EIOCBQUEUED;
 954                 /*
 955                  * Do not kfree the buffer in this function.  It will be freed
 956                  * by ffs_user_copy_worker.
 957                  */
 958                 data = NULL;
 959         }
 960
 961 error_lock:
 962         spin_unlock_irq(&epfile->ffs->eps_lock);
 963 error_mutex:
 964         mutex_unlock(&epfile->mutex);
 965 error:
 966         kfree(data);
 967         return ret;
 968 }
 969
 970 static int
 971 ffs_epfile_open(struct inode *inode, struct file *file)
 972 {
 973         struct ffs_epfile *epfile = inode->i_private;
 974
 975         ENTER();
 976
 977         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
 978                 return -ENODEV;
 979
 980         file->private_data = epfile;
 981         ffs_data_opened(epfile->ffs);
 982
 983         return 0;
 984 }
 985
 986 static int ffs_aio_cancel(struct kiocb *kiocb)
 987 {
 988         struct ffs_io_data *io_data = kiocb->private;
 989         struct ffs_epfile *epfile = kiocb->ki_filp->private_data;
 990         int value;
 991
 992         ENTER();
 993
 994         spin_lock_irq(&epfile->ffs->eps_lock);
 995
 996         if (likely(io_data && io_data->ep && io_data->req))
 997                 value = usb_ep_dequeue(io_data->ep, io_data->req);
 998         else
 999                 value = -EINVAL;
1000
1001         spin_unlock_irq(&epfile->ffs->eps_lock);
1002
1003         return value;
1004 }
1005
1006 static ssize_t ffs_epfile_write_iter(struct kiocb *kiocb, struct iov_iter *from)
1007 {
1008         struct ffs_io_data io_data, *p = &io_data;
1009         ssize_t res;
1010
1011         ENTER();
1012
1013         if (!is_sync_kiocb(kiocb)) {
1014                 p = kmalloc(sizeof(io_data), GFP_KERNEL);
1015                 if (unlikely(!p))
1016                         return -ENOMEM;
1017                 p->aio = true;
1018         } else {
1019                 p->aio = false;
1020         }
1021
1022         p->read = false;
1023         p->kiocb = kiocb;
1024         p->data = *from;
1025         p->mm = current->mm;
1026
1027         kiocb->private = p;
1028
1029         if (p->aio)
1030                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1031
1032         res = ffs_epfile_io(kiocb->ki_filp, p);
1033         if (res == -EIOCBQUEUED)
1034                 return res;
1035         if (p->aio)
1036                 kfree(p);
1037         else
1038                 *from = p->data;
1039         return res;
1040 }
1041
1042 static ssize_t ffs_epfile_read_iter(struct kiocb *kiocb, struct iov_iter *to)
1043 {
1044         struct ffs_io_data io_data, *p = &io_data;
1045         ssize_t res;
1046
1047         ENTER();
1048
1049         if (!is_sync_kiocb(kiocb)) {
1050                 p = kmalloc(sizeof(io_data), GFP_KERNEL);
1051                 if (unlikely(!p))
1052                         return -ENOMEM;
1053                 p->aio = true;
1054         } else {
1055                 p->aio = false;
1056         }
1057
1058         p->read = true;
1059         p->kiocb = kiocb;
1060         if (p->aio) {
1061                 p->to_free = dup_iter(&p->data, to, GFP_KERNEL);
1062                 if (!p->to_free) {
1063                         kfree(p);
1064                         return -ENOMEM;
1065                 }
1066         } else {
1067                 p->data = *to;
1068                 p->to_free = NULL;
1069         }
1070         p->mm = current->mm;
1071
1072         kiocb->private = p;
1073
1074         if (p->aio)
1075                 kiocb_set_cancel_fn(kiocb, ffs_aio_cancel);
1076
1077         res = ffs_epfile_io(kiocb->ki_filp, p);
1078         if (res == -EIOCBQUEUED)
1079                 return res;
1080
1081         if (p->aio) {
1082                 kfree(p->to_free);
1083                 kfree(p);
1084         } else {
1085                 *to = p->data;
1086         }
1087         return res;
1088 }
1089
1090 static int
1091 ffs_epfile_release(struct inode *inode, struct file *file)
1092 {
1093         struct ffs_epfile *epfile = inode->i_private;
1094
1095         ENTER();
1096
1097         kfree(epfile->read_buffer);
1098         epfile->read_buffer = NULL;
1099         ffs_data_closed(epfile->ffs);
1100
1101         return 0;
1102 }
1103
1104 static long ffs_epfile_ioctl(struct file *file, unsigned code,
1105                              unsigned long value)
1106 {
1107         struct ffs_epfile *epfile = file->private_data;
1108         int ret;
1109
1110         ENTER();
1111
1112         if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
1113                 return -ENODEV;
1114
1115         spin_lock_irq(&epfile->ffs->eps_lock);
1116         if (likely(epfile->ep)) {
1117                 switch (code) {
1118                 case FUNCTIONFS_FIFO_STATUS:
1119                         ret = usb_ep_fifo_status(epfile->ep->ep);
1120                         break;
1121                 case FUNCTIONFS_FIFO_FLUSH:
1122                         usb_ep_fifo_flush(epfile->ep->ep);
1123                         ret = 0;
1124                         break;
1125                 case FUNCTIONFS_CLEAR_HALT:
1126                         ret = usb_ep_clear_halt(epfile->ep->ep);
1127                         break;
1128                 case FUNCTIONFS_ENDPOINT_REVMAP:
1129                         ret = epfile->ep->num;
1130                         break;
1131                 case FUNCTIONFS_ENDPOINT_DESC:
1132                 {
1133                         int desc_idx;
1134                         struct usb_endpoint_descriptor *desc;
1135
1136                         switch (epfile->ffs->gadget->speed) {
1137                         case USB_SPEED_SUPER:
1138                                 desc_idx = 2;
1139                                 break;
1140                         case USB_SPEED_HIGH:
1141                                 desc_idx = 1;
1142                                 break;
1143                         default:
1144                                 desc_idx = 0;
1145                         }
1146                         desc = epfile->ep->descs[desc_idx];
1147
1148                         spin_unlock_irq(&epfile->ffs->eps_lock);
1149                         ret = copy_to_user((void *)value, desc, sizeof(*desc));
1150                         if (ret)
1151                                 ret = -EFAULT;
1152                         return ret;
1153                 }
1154                 default:
1155                         ret = -ENOTTY;
1156                 }
1157         } else {
1158                 ret = -ENODEV;
1159         }
1160         spin_unlock_irq(&epfile->ffs->eps_lock);
1161
1162         return ret;
1163 }
1164
1165 static const struct file_operations ffs_epfile_operations = {
1166         .llseek =       no_llseek,
1167
1168         .open =         ffs_epfile_open,
1169         .write_iter =   ffs_epfile_write_iter,
1170         .read_iter =    ffs_epfile_read_iter,
1171         .release =      ffs_epfile_release,
1172         .unlocked_ioctl =       ffs_epfile_ioctl,
1173 };
1174
1175
1176 /* File system and super block operations ***********************************/
1177
1178 /*
1179  * Mounting the file system creates a controller file, used first for
1180  * function configuration then later for event monitoring.
1181  */
1182
1183 static struct inode *__must_check
1184 ffs_sb_make_inode(struct super_block *sb, void *data,
1185                   const struct file_operations *fops,
1186                   const struct inode_operations *iops,
1187                   struct ffs_file_perms *perms)
1188 {
1189         struct inode *inode;
1190
1191         ENTER();
1192
1193         inode = new_inode(sb);
1194
1195         if (likely(inode)) {
1196                 struct timespec current_time = CURRENT_TIME;
1197
1198                 inode->i_ino     = get_next_ino();
1199                 inode->i_mode    = perms->mode;
1200                 inode->i_uid     = perms->uid;
1201                 inode->i_gid     = perms->gid;
1202                 inode->i_atime   = current_time;
1203                 inode->i_mtime   = current_time;
1204                 inode->i_ctime   = current_time;
1205                 inode->i_private = data;
1206                 if (fops)
1207                         inode->i_fop = fops;
1208                 if (iops)
1209                         inode->i_op  = iops;
1210         }
1211
1212         return inode;
1213 }
1214
1215 /* Create "regular" file */
1216 static struct dentry *ffs_sb_create_file(struct super_block *sb,
1217                                         const char *name, void *data,
1218                                         const struct file_operations *fops)
1219 {
1220         struct ffs_data *ffs = sb->s_fs_info;
1221         struct dentry   *dentry;
1222         struct inode    *inode;
1223
1224         ENTER();
1225
1226         dentry = d_alloc_name(sb->s_root, name);
1227         if (unlikely(!dentry))
1228                 return NULL;
1229
1230         inode = ffs_sb_make_inode(sb, data, fops, NULL, &ffs->file_perms);
1231         if (unlikely(!inode)) {
1232                 dput(dentry);
1233                 return NULL;
1234         }
1235
1236         d_add(dentry, inode);
1237         return dentry;
1238 }
1239
1240 /* Super block */
1241 static const struct super_operations ffs_sb_operations = {
1242         .statfs =       simple_statfs,
1243         .drop_inode =   generic_delete_inode,
1244 };
1245
1246 struct ffs_sb_fill_data {
1247         struct ffs_file_perms perms;
1248         umode_t root_mode;
1249         const char *dev_name;
1250         bool no_disconnect;
1251         struct ffs_data *ffs_data;
1252 };
1253
1254 static int ffs_sb_fill(struct super_block *sb, void *_data, int silent)
1255 {
1256         struct ffs_sb_fill_data *data = _data;
1257         struct inode    *inode;
1258         struct ffs_data *ffs = data->ffs_data;
1259
1260         ENTER();
1261
1262         ffs->sb              = sb;
1263         data->ffs_data       = NULL;
1264         sb->s_fs_info        = ffs;
1265         sb->s_blocksize      = PAGE_SIZE;
1266         sb->s_blocksize_bits = PAGE_SHIFT;
1267         sb->s_magic          = FUNCTIONFS_MAGIC;
1268         sb->s_op             = &ffs_sb_operations;
1269         sb->s_time_gran      = 1;
1270
1271         /* Root inode */
1272         data->perms.mode = data->root_mode;
1273         inode = ffs_sb_make_inode(sb, NULL,
1274                                   &simple_dir_operations,
1275                                   &simple_dir_inode_operations,
1276                                   &data->perms);
1277         sb->s_root = d_make_root(inode);
1278         if (unlikely(!sb->s_root))
1279                 return -ENOMEM;
1280
1281         /* EP0 file */
1282         if (unlikely(!ffs_sb_create_file(sb, "ep0", ffs,
1283                                          &ffs_ep0_operations)))
1284                 return -ENOMEM;
1285
1286         return 0;
1287 }
1288
1289 static int ffs_fs_parse_opts(struct ffs_sb_fill_data *data, char *opts)
1290 {
1291         ENTER();
1292
1293         if (!opts || !*opts)
1294                 return 0;
1295
1296         for (;;) {
1297                 unsigned long value;
1298                 char *eq, *comma;
1299
1300                 /* Option limit */
1301                 comma = strchr(opts, ',');
1302                 if (comma)
1303                         *comma = 0;
1304
1305                 /* Value limit */
1306                 eq = strchr(opts, '=');
1307                 if (unlikely(!eq)) {
1308                         pr_err("'=' missing in %s\n", opts);
1309                         return -EINVAL;
1310                 }
1311                 *eq = 0;
1312
1313                 /* Parse value */
1314                 if (kstrtoul(eq + 1, 0, &value)) {
1315                         pr_err("%s: invalid value: %s\n", opts, eq + 1);
1316                         return -EINVAL;
1317                 }
1318
1319                 /* Interpret option */
1320                 switch (eq - opts) {
1321                 case 13:
1322                         if (!memcmp(opts, "no_disconnect", 13))
1323                                 data->no_disconnect = !!value;
1324                         else
1325                                 goto invalid;
1326                         break;
1327                 case 5:
1328                         if (!memcmp(opts, "rmode", 5))
1329                                 data->root_mode  = (value & 0555) | S_IFDIR;
1330                         else if (!memcmp(opts, "fmode", 5))
1331                                 data->perms.mode = (value & 0666) | S_IFREG;
1332                         else
1333                                 goto invalid;
1334                         break;
1335
1336                 case 4:
1337                         if (!memcmp(opts, "mode", 4)) {
1338                                 data->root_mode  = (value & 0555) | S_IFDIR;
1339                                 data->perms.mode = (value & 0666) | S_IFREG;
1340                         } else {
1341                                 goto invalid;
1342                         }
1343                         break;
1344
1345                 case 3:
1346                         if (!memcmp(opts, "uid", 3)) {
1347                                 data->perms.uid = make_kuid(current_user_ns(), value);
1348                                 if (!uid_valid(data->perms.uid)) {
1349                                         pr_err("%s: unmapped value: %lu\n", opts, value);
1350                                         return -EINVAL;
1351                                 }
1352                         } else if (!memcmp(opts, "gid", 3)) {
1353                                 data->perms.gid = make_kgid(current_user_ns(), value);
1354                                 if (!gid_valid(data->perms.gid)) {
1355                                         pr_err("%s: unmapped value: %lu\n", opts, value);
1356                                         return -EINVAL;
1357                                 }
1358                         } else {
1359                                 goto invalid;
1360                         }
1361                         break;
1362
1363                 default:
1364 invalid:
1365                         pr_err("%s: invalid option\n", opts);
1366                         return -EINVAL;
1367                 }
1368
1369                 /* Next iteration */
1370                 if (!comma)
1371                         break;
1372                 opts = comma + 1;
1373         }
1374
1375         return 0;
1376 }
1377
1378 /* "mount -t functionfs dev_name /dev/function" ends up here */
1379
1380 static struct dentry *
1381 ffs_fs_mount(struct file_system_type *t, int flags,
1382               const char *dev_name, void *opts)
1383 {
1384         struct ffs_sb_fill_data data = {
1385                 .perms = {
1386                         .mode = S_IFREG | 0600,
1387                         .uid = GLOBAL_ROOT_UID,
1388                         .gid = GLOBAL_ROOT_GID,
1389                 },
1390                 .root_mode = S_IFDIR | 0500,
1391                 .no_disconnect = false,
1392         };
1393         struct dentry *rv;
1394         int ret;
1395         void *ffs_dev;
1396         struct ffs_data *ffs;
1397
1398         ENTER();
1399
1400         ret = ffs_fs_parse_opts(&data, opts);
1401         if (unlikely(ret < 0))
1402                 return ERR_PTR(ret);
1403
1404         ffs = ffs_data_new();
1405         if (unlikely(!ffs))
1406                 return ERR_PTR(-ENOMEM);
1407         ffs->file_perms = data.perms;
1408         ffs->no_disconnect = data.no_disconnect;
1409
1410         ffs->dev_name = kstrdup(dev_name, GFP_KERNEL);
1411         if (unlikely(!ffs->dev_name)) {
1412                 ffs_data_put(ffs);
1413                 return ERR_PTR(-ENOMEM);
1414         }
1415
1416         ffs_dev = ffs_acquire_dev(dev_name);
1417         if (IS_ERR(ffs_dev)) {
1418                 ffs_data_put(ffs);
1419                 return ERR_CAST(ffs_dev);
1420         }
1421         ffs->private_data = ffs_dev;
1422         data.ffs_data = ffs;
1423
1424         rv = mount_nodev(t, flags, &data, ffs_sb_fill);
1425         if (IS_ERR(rv) && data.ffs_data) {
1426                 ffs_release_dev(data.ffs_data);
1427                 ffs_data_put(data.ffs_data);
1428         }
1429         return rv;
1430 }
1431
1432 static void
1433 ffs_fs_kill_sb(struct super_block *sb)
1434 {
1435         ENTER();
1436
1437         kill_litter_super(sb);
1438         if (sb->s_fs_info) {
1439                 ffs_release_dev(sb->s_fs_info);
1440                 ffs_data_closed(sb->s_fs_info);
1441                 ffs_data_put(sb->s_fs_info);
1442         }
1443 }
1444
1445 static struct file_system_type ffs_fs_type = {
1446         .owner          = THIS_MODULE,
1447         .name           = "functionfs",
1448         .mount          = ffs_fs_mount,
1449         .kill_sb        = ffs_fs_kill_sb,
1450 };
1451 MODULE_ALIAS_FS("functionfs");
1452
1453
1454 /* Driver's main init/cleanup functions *************************************/
1455
1456 static int functionfs_init(void)
1457 {
1458         int ret;
1459
1460         ENTER();
1461
1462         ret = register_filesystem(&ffs_fs_type);
1463         if (likely(!ret))
1464                 pr_info("file system registered\n");
1465         else
1466                 pr_err("failed registering file system (%d)\n", ret);
1467
1468         return ret;
1469 }
1470
1471 static void functionfs_cleanup(void)
1472 {
1473         ENTER();
1474
1475         pr_info("unloading\n");
1476         unregister_filesystem(&ffs_fs_type);
1477 }
1478
1479
1480 /* ffs_data and ffs_function construction and destruction code **************/
1481
1482 static void ffs_data_clear(struct ffs_data *ffs);
1483 static void ffs_data_reset(struct ffs_data *ffs);
1484
1485 static void ffs_data_get(struct ffs_data *ffs)
1486 {
1487         ENTER();
1488
1489         atomic_inc(&ffs->ref);
1490 }
1491
1492 static void ffs_data_opened(struct ffs_data *ffs)
1493 {
1494         ENTER();
1495
1496         atomic_inc(&ffs->ref);
1497         if (atomic_add_return(1, &ffs->opened) == 1 &&
1498                         ffs->state == FFS_DEACTIVATED) {
1499                 ffs->state = FFS_CLOSING;
1500                 ffs_data_reset(ffs);
1501         }
1502 }
1503
1504 static void ffs_data_put(struct ffs_data *ffs)
1505 {
1506         ENTER();
1507
1508         if (unlikely(atomic_dec_and_test(&ffs->ref))) {
1509                 pr_info("%s(): freeing\n", __func__);
1510                 ffs_data_clear(ffs);
1511                 BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
1512                        waitqueue_active(&ffs->ep0req_completion.wait));
1513                 kfree(ffs->dev_name);
1514                 kfree(ffs);
1515         }
1516 }
1517
1518 static void ffs_data_closed(struct ffs_data *ffs)
1519 {
1520         ENTER();
1521
1522         if (atomic_dec_and_test(&ffs->opened)) {
1523                 if (ffs->no_disconnect) {
1524                         ffs->state = FFS_DEACTIVATED;
1525                         if (ffs->epfiles) {
1526                                 ffs_epfiles_destroy(ffs->epfiles,
1527                                                    ffs->eps_count);
1528                                 ffs->epfiles = NULL;
1529                         }
1530                         if (ffs->setup_state == FFS_SETUP_PENDING)
1531                                 __ffs_ep0_stall(ffs);
1532                 } else {
1533                         ffs->state = FFS_CLOSING;
1534                         ffs_data_reset(ffs);
1535                 }
1536         }
1537         if (atomic_read(&ffs->opened) < 0) {
1538                 ffs->state = FFS_CLOSING;
1539                 ffs_data_reset(ffs);
1540         }
1541
1542         ffs_data_put(ffs);
1543 }
1544
1545 static struct ffs_data *ffs_data_new(void)
1546 {
1547         struct ffs_data *ffs = kzalloc(sizeof *ffs, GFP_KERNEL);
1548         if (unlikely(!ffs))
1549                 return NULL;
1550
1551         ENTER();
1552
1553         atomic_set(&ffs->ref, 1);
1554         atomic_set(&ffs->opened, 0);
1555         ffs->state = FFS_READ_DESCRIPTORS;
1556         mutex_init(&ffs->mutex);
1557         spin_lock_init(&ffs->eps_lock);
1558         init_waitqueue_head(&ffs->ev.waitq);
1559         init_completion(&ffs->ep0req_completion);
1560
1561         /* XXX REVISIT need to update it in some places, or do we? */
1562         ffs->ev.can_stall = 1;
1563
1564         return ffs;
1565 }
1566
1567 static void ffs_data_clear(struct ffs_data *ffs)
1568 {
1569         ENTER();
1570
1571         ffs_closed(ffs);
1572
1573         BUG_ON(ffs->gadget);
1574
1575         if (ffs->epfiles)
1576                 ffs_epfiles_destroy(ffs->epfiles, ffs->eps_count);
1577
1578         if (ffs->ffs_eventfd)
1579                 eventfd_ctx_put(ffs->ffs_eventfd);
1580
1581         kfree(ffs->raw_descs_data);
1582         kfree(ffs->raw_strings);
1583         kfree(ffs->stringtabs);
1584 }
1585
1586 static void ffs_data_reset(struct ffs_data *ffs)
1587 {
1588         ENTER();
1589
1590         ffs_data_clear(ffs);
1591
1592         ffs->epfiles = NULL;
1593         ffs->raw_descs_data = NULL;
1594         ffs->raw_descs = NULL;
1595         ffs->raw_strings = NULL;
1596         ffs->stringtabs = NULL;
1597
1598         ffs->raw_descs_length = 0;
1599         ffs->fs_descs_count = 0;
1600         ffs->hs_descs_count = 0;
1601         ffs->ss_descs_count = 0;
1602
1603         ffs->strings_count = 0;
1604         ffs->interfaces_count = 0;
1605         ffs->eps_count = 0;
1606
1607         ffs->ev.count = 0;
1608
1609         ffs->state = FFS_READ_DESCRIPTORS;
1610         ffs->setup_state = FFS_NO_SETUP;
1611         ffs->flags = 0;
1612 }
1613
1614
1615 static int functionfs_bind(struct ffs_data *ffs, struct usb_composite_dev *cdev)
1616 {
1617         struct usb_gadget_strings **lang;
1618         int first_id;
1619
1620         ENTER();
1621
1622         if (WARN_ON(ffs->state != FFS_ACTIVE
1623                  || test_and_set_bit(FFS_FL_BOUND, &ffs->flags)))
1624                 return -EBADFD;
1625
1626         first_id = usb_string_ids_n(cdev, ffs->strings_count);
1627         if (unlikely(first_id < 0))
1628                 return first_id;
1629
1630         ffs->ep0req = usb_ep_alloc_request(cdev->gadget->ep0, GFP_KERNEL);
1631         if (unlikely(!ffs->ep0req))
1632                 return -ENOMEM;
1633         ffs->ep0req->complete = ffs_ep0_complete;
1634         ffs->ep0req->context = ffs;
1635
1636         lang = ffs->stringtabs;
1637         if (lang) {
1638                 for (; *lang; ++lang) {
1639                         struct usb_string *str = (*lang)->strings;
1640                         int id = first_id;
1641                         for (; str->s; ++id, ++str)
1642                                 str->id = id;
1643                 }
1644         }
1645
1646         ffs->gadget = cdev->gadget;
1647         ffs_data_get(ffs);
1648         return 0;
1649 }
1650
1651 static void functionfs_unbind(struct ffs_data *ffs)
1652 {
1653         ENTER();
1654
1655         if (!WARN_ON(!ffs->gadget)) {
1656                 usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req);
1657                 ffs->ep0req = NULL;
1658                 ffs->gadget = NULL;
1659                 clear_bit(FFS_FL_BOUND, &ffs->flags);
1660                 ffs_data_put(ffs);
1661         }
1662 }
1663
1664 static int ffs_epfiles_create(struct ffs_data *ffs)
1665 {
1666         struct ffs_epfile *epfile, *epfiles;
1667         unsigned i, count;
1668
1669         ENTER();
1670
1671         count = ffs->eps_count;
1672         epfiles = kcalloc(count, sizeof(*epfiles), GFP_KERNEL);
1673         if (!epfiles)
1674                 return -ENOMEM;
1675
1676         epfile = epfiles;
1677         for (i = 1; i <= count; ++i, ++epfile) {
1678                 epfile->ffs = ffs;
1679                 mutex_init(&epfile->mutex);
1680                 init_waitqueue_head(&epfile->wait);
1681                 if (ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
1682                         sprintf(epfile->name, "ep%02x", ffs->eps_addrmap[i]);
1683                 else
1684                         sprintf(epfile->name, "ep%u", i);
1685                 epfile->dentry = ffs_sb_create_file(ffs->sb, epfile->name,
1686                                                  epfile,
1687                                                  &ffs_epfile_operations);
1688                 if (unlikely(!epfile->dentry)) {
1689                         ffs_epfiles_destroy(epfiles, i - 1);
1690                         return -ENOMEM;
1691                 }
1692         }
1693
1694         ffs->epfiles = epfiles;
1695         return 0;
1696 }
1697
1698 static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
1699 {
1700         struct ffs_epfile *epfile = epfiles;
1701
1702         ENTER();
1703
1704         for (; count; --count, ++epfile) {
1705                 BUG_ON(mutex_is_locked(&epfile->mutex) ||
1706                        waitqueue_active(&epfile->wait));
1707                 if (epfile->dentry) {
1708                         d_delete(epfile->dentry);
1709                         dput(epfile->dentry);
1710                         epfile->dentry = NULL;
1711                 }
1712         }
1713
1714         kfree(epfiles);
1715 }
1716
1717 static void ffs_func_eps_disable(struct ffs_function *func)
1718 {
1719         struct ffs_ep *ep         = func->eps;
1720         struct ffs_epfile *epfile = func->ffs->epfiles;
1721         unsigned count            = func->ffs->eps_count;
1722         unsigned long flags;
1723
1724         do {
1725                 if (epfile)
1726                         mutex_lock(&epfile->mutex);
1727                 spin_lock_irqsave(&func->ffs->eps_lock, flags);
1728                 /* pending requests get nuked */
1729                 if (likely(ep->ep))
1730                         usb_ep_disable(ep->ep);
1731                 ++ep;
1732                 spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1733
1734                 if (epfile) {
1735                         epfile->ep = NULL;
1736                         kfree(epfile->read_buffer);
1737                         epfile->read_buffer = NULL;
1738                         mutex_unlock(&epfile->mutex);
1739                         ++epfile;
1740                 }
1741         } while (--count);
1742 }
1743
1744 static int ffs_func_eps_enable(struct ffs_function *func)
1745 {
1746         struct ffs_data *ffs      = func->ffs;
1747         struct ffs_ep *ep         = func->eps;
1748         struct ffs_epfile *epfile = ffs->epfiles;
1749         unsigned count            = ffs->eps_count;
1750         unsigned long flags;
1751         int ret = 0;
1752
1753         spin_lock_irqsave(&func->ffs->eps_lock, flags);
1754         do {
1755                 struct usb_endpoint_descriptor *ds;
1756                 int desc_idx;
1757
1758                 if (ffs->gadget->speed == USB_SPEED_SUPER)
1759                         desc_idx = 2;
1760                 else if (ffs->gadget->speed == USB_SPEED_HIGH)
1761                         desc_idx = 1;
1762                 else
1763                         desc_idx = 0;
1764
1765                 /* fall-back to lower speed if desc missing for current speed */
1766                 do {
1767                         ds = ep->descs[desc_idx];
1768                 } while (!ds && --desc_idx >= 0);
1769
1770                 if (!ds) {
1771                         ret = -EINVAL;
1772                         break;
1773                 }
1774
1775                 ep->ep->driver_data = ep;
1776                 ep->ep->desc = ds;
1777                 ret = usb_ep_enable(ep->ep);
1778                 if (likely(!ret)) {
1779                         epfile->ep = ep;
1780                         epfile->in = usb_endpoint_dir_in(ds);
1781                         epfile->isoc = usb_endpoint_xfer_isoc(ds);
1782                 } else {
1783                         break;
1784                 }
1785
1786                 wake_up(&epfile->wait);
1787
1788                 ++ep;
1789                 ++epfile;
1790         } while (--count);
1791         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
1792
1793         return ret;
1794 }
1795
1796
1797 /* Parsing and building descriptors and strings *****************************/
1798
1799 /*
1800  * This validates if data pointed by data is a valid USB descriptor as
1801  * well as record how many interfaces, endpoints and strings are
1802  * required by given configuration.  Returns address after the
1803  * descriptor or NULL if data is invalid.
1804  */
1805
1806 enum ffs_entity_type {
1807         FFS_DESCRIPTOR, FFS_INTERFACE, FFS_STRING, FFS_ENDPOINT
1808 };
1809
1810 enum ffs_os_desc_type {
1811         FFS_OS_DESC, FFS_OS_DESC_EXT_COMPAT, FFS_OS_DESC_EXT_PROP
1812 };
1813
1814 typedef int (*ffs_entity_callback)(enum ffs_entity_type entity,
1815                                    u8 *valuep,
1816                                    struct usb_descriptor_header *desc,
1817                                    void *priv);
1818
1819 typedef int (*ffs_os_desc_callback)(enum ffs_os_desc_type entity,
1820                                     struct usb_os_desc_header *h, void *data,
1821                                     unsigned len, void *priv);
1822
1823 static int __must_check ffs_do_single_desc(char *data, unsigned len,
1824                                            ffs_entity_callback entity,
1825                                            void *priv)
1826 {
1827         struct usb_descriptor_header *_ds = (void *)data;
1828         u8 length;
1829         int ret;
1830
1831         ENTER();
1832
1833         /* At least two bytes are required: length and type */
1834         if (len < 2) {
1835                 pr_vdebug("descriptor too short\n");
1836                 return -EINVAL;
1837         }
1838
1839         /* If we have at least as many bytes as the descriptor takes? */
1840         length = _ds->bLength;
1841         if (len < length) {
1842                 pr_vdebug("descriptor longer then available data\n");
1843                 return -EINVAL;
1844         }
1845
1846 #define __entity_check_INTERFACE(val)  1
1847 #define __entity_check_STRING(val)     (val)
1848 #define __entity_check_ENDPOINT(val)   ((val) & USB_ENDPOINT_NUMBER_MASK)
1849 #define __entity(type, val) do {                                        \
1850                 pr_vdebug("entity " #type "(%02x)\n", (val));           \
1851                 if (unlikely(!__entity_check_ ##type(val))) {           \
1852                         pr_vdebug("invalid entity's value\n");          \
1853                         return -EINVAL;                                 \
1854                 }                                                       \
1855                 ret = entity(FFS_ ##type, &val, _ds, priv);             \
1856                 if (unlikely(ret < 0)) {                                \
1857                         pr_debug("entity " #type "(%02x); ret = %d\n",  \
1858                                  (val), ret);                           \
1859                         return ret;                                     \
1860                 }                                                       \
1861         } while (0)
1862
1863         /* Parse descriptor depending on type. */
1864         switch (_ds->bDescriptorType) {
1865         case USB_DT_DEVICE:
1866         case USB_DT_CONFIG:
1867         case USB_DT_STRING:
1868         case USB_DT_DEVICE_QUALIFIER:
1869                 /* function can't have any of those */
1870                 pr_vdebug("descriptor reserved for gadget: %d\n",
1871                       _ds->bDescriptorType);
1872                 return -EINVAL;
1873
1874         case USB_DT_INTERFACE: {
1875                 struct usb_interface_descriptor *ds = (void *)_ds;
1876                 pr_vdebug("interface descriptor\n");
1877                 if (length != sizeof *ds)
1878                         goto inv_length;
1879
1880                 __entity(INTERFACE, ds->bInterfaceNumber);
1881                 if (ds->iInterface)
1882                         __entity(STRING, ds->iInterface);
1883         }
1884                 break;
1885
1886         case USB_DT_ENDPOINT: {
1887                 struct usb_endpoint_descriptor *ds = (void *)_ds;
1888                 pr_vdebug("endpoint descriptor\n");
1889                 if (length != USB_DT_ENDPOINT_SIZE &&
1890                     length != USB_DT_ENDPOINT_AUDIO_SIZE)
1891                         goto inv_length;
1892                 __entity(ENDPOINT, ds->bEndpointAddress);
1893         }
1894                 break;
1895
1896         case HID_DT_HID:
1897                 pr_vdebug("hid descriptor\n");
1898                 if (length != sizeof(struct hid_descriptor))
1899                         goto inv_length;
1900                 break;
1901
1902         case USB_DT_OTG:
1903                 if (length != sizeof(struct usb_otg_descriptor))
1904                         goto inv_length;
1905                 break;
1906
1907         case USB_DT_INTERFACE_ASSOCIATION: {
1908                 struct usb_interface_assoc_descriptor *ds = (void *)_ds;
1909                 pr_vdebug("interface association descriptor\n");
1910                 if (length != sizeof *ds)
1911                         goto inv_length;
1912                 if (ds->iFunction)
1913                         __entity(STRING, ds->iFunction);
1914         }
1915                 break;
1916
1917         case USB_DT_SS_ENDPOINT_COMP:
1918                 pr_vdebug("EP SS companion descriptor\n");
1919                 if (length != sizeof(struct usb_ss_ep_comp_descriptor))
1920                         goto inv_length;
1921                 break;
1922
1923         case USB_DT_OTHER_SPEED_CONFIG:
1924         case USB_DT_INTERFACE_POWER:
1925         case USB_DT_DEBUG:
1926         case USB_DT_SECURITY:
1927         case USB_DT_CS_RADIO_CONTROL:
1928                 /* TODO */
1929                 pr_vdebug("unimplemented descriptor: %d\n", _ds->bDescriptorType);
1930                 return -EINVAL;
1931
1932         default:
1933                 /* We should never be here */
1934                 pr_vdebug("unknown descriptor: %d\n", _ds->bDescriptorType);
1935                 return -EINVAL;
1936
1937 inv_length:
1938                 pr_vdebug("invalid length: %d (descriptor %d)\n",
1939                           _ds->bLength, _ds->bDescriptorType);
1940                 return -EINVAL;
1941         }
1942
1943 #undef __entity
1944 #undef __entity_check_DESCRIPTOR
1945 #undef __entity_check_INTERFACE
1946 #undef __entity_check_STRING
1947 #undef __entity_check_ENDPOINT
1948
1949         return length;
1950 }
1951
1952 static int __must_check ffs_do_descs(unsigned count, char *data, unsigned len,
1953                                      ffs_entity_callback entity, void *priv)
1954 {
1955         const unsigned _len = len;
1956         unsigned long num = 0;
1957
1958         ENTER();
1959
1960         for (;;) {
1961                 int ret;
1962
1963                 if (num == count)
1964                         data = NULL;
1965
1966                 /* Record "descriptor" entity */
1967                 ret = entity(FFS_DESCRIPTOR, (u8 *)num, (void *)data, priv);
1968                 if (unlikely(ret < 0)) {
1969                         pr_debug("entity DESCRIPTOR(%02lx); ret = %d\n",
1970                                  num, ret);
1971                         return ret;
1972                 }
1973
1974                 if (!data)
1975                         return _len - len;
1976
1977                 ret = ffs_do_single_desc(data, len, entity, priv);
1978                 if (unlikely(ret < 0)) {
1979                         pr_debug("%s returns %d\n", __func__, ret);
1980                         return ret;
1981                 }
1982
1983                 len -= ret;
1984                 data += ret;
1985                 ++num;
1986         }
1987 }
1988
1989 static int __ffs_data_do_entity(enum ffs_entity_type type,
1990                                 u8 *valuep, struct usb_descriptor_header *desc,
1991                                 void *priv)
1992 {
1993         struct ffs_desc_helper *helper = priv;
1994         struct usb_endpoint_descriptor *d;
1995
1996         ENTER();
1997
1998         switch (type) {
1999         case FFS_DESCRIPTOR:
2000                 break;
2001
2002         case FFS_INTERFACE:
2003                 /*
2004                  * Interfaces are indexed from zero so if we
2005                  * encountered interface "n" then there are at least
2006                  * "n+1" interfaces.
2007                  */
2008                 if (*valuep >= helper->interfaces_count)
2009                         helper->interfaces_count = *valuep + 1;
2010                 break;
2011
2012         case FFS_STRING:
2013                 /*
2014                  * Strings are indexed from 1 (0 is magic ;) reserved
2015                  * for languages list or some such)
2016                  */
2017                 if (*valuep > helper->ffs->strings_count)
2018                         helper->ffs->strings_count = *valuep;
2019                 break;
2020
2021         case FFS_ENDPOINT:
2022                 d = (void *)desc;
2023                 helper->eps_count++;
2024                 if (helper->eps_count >= 15)
2025                         return -EINVAL;
2026                 /* Check if descriptors for any speed were already parsed */
2027                 if (!helper->ffs->eps_count && !helper->ffs->interfaces_count)
2028                         helper->ffs->eps_addrmap[helper->eps_count] =
2029                                 d->bEndpointAddress;
2030                 else if (helper->ffs->eps_addrmap[helper->eps_count] !=
2031                                 d->bEndpointAddress)
2032                         return -EINVAL;
2033                 break;
2034         }
2035
2036         return 0;
2037 }
2038
2039 static int __ffs_do_os_desc_header(enum ffs_os_desc_type *next_type,
2040                                    struct usb_os_desc_header *desc)
2041 {
2042         u16 bcd_version = le16_to_cpu(desc->bcdVersion);
2043         u16 w_index = le16_to_cpu(desc->wIndex);
2044
2045         if (bcd_version != 1) {
2046                 pr_vdebug("unsupported os descriptors version: %d",
2047                           bcd_version);
2048                 return -EINVAL;
2049         }
2050         switch (w_index) {
2051         case 0x4:
2052                 *next_type = FFS_OS_DESC_EXT_COMPAT;
2053                 break;
2054         case 0x5:
2055                 *next_type = FFS_OS_DESC_EXT_PROP;
2056                 break;
2057         default:
2058                 pr_vdebug("unsupported os descriptor type: %d", w_index);
2059                 return -EINVAL;
2060         }
2061
2062         return sizeof(*desc);
2063 }
2064
2065 /*
2066  * Process all extended compatibility/extended property descriptors
2067  * of a feature descriptor
2068  */
2069 static int __must_check ffs_do_single_os_desc(char *data, unsigned len,
2070                                               enum ffs_os_desc_type type,
2071                                               u16 feature_count,
2072                                               ffs_os_desc_callback entity,
2073                                               void *priv,
2074                                               struct usb_os_desc_header *h)
2075 {
2076         int ret;
2077         const unsigned _len = len;
2078
2079         ENTER();
2080
2081         /* loop over all ext compat/ext prop descriptors */
2082         while (feature_count--) {
2083                 ret = entity(type, h, data, len, priv);
2084                 if (unlikely(ret < 0)) {
2085                         pr_debug("bad OS descriptor, type: %d\n", type);
2086                         return ret;
2087                 }
2088                 data += ret;
2089                 len -= ret;
2090         }
2091         return _len - len;
2092 }
2093
2094 /* Process a number of complete Feature Descriptors (Ext Compat or Ext Prop) */
2095 static int __must_check ffs_do_os_descs(unsigned count,
2096                                         char *data, unsigned len,
2097                                         ffs_os_desc_callback entity, void *priv)
2098 {
2099         const unsigned _len = len;
2100         unsigned long num = 0;
2101
2102         ENTER();
2103
2104         for (num = 0; num < count; ++num) {
2105                 int ret;
2106                 enum ffs_os_desc_type type;
2107                 u16 feature_count;
2108                 struct usb_os_desc_header *desc = (void *)data;
2109
2110                 if (len < sizeof(*desc))
2111                         return -EINVAL;
2112
2113                 /*
2114                  * Record "descriptor" entity.
2115                  * Process dwLength, bcdVersion, wIndex, get b/wCount.
2116                  * Move the data pointer to the beginning of extended
2117                  * compatibilities proper or extended properties proper
2118                  * portions of the data
2119                  */
2120                 if (le32_to_cpu(desc->dwLength) > len)
2121                         return -EINVAL;
2122
2123                 ret = __ffs_do_os_desc_header(&type, desc);
2124                 if (unlikely(ret < 0)) {
2125                         pr_debug("entity OS_DESCRIPTOR(%02lx); ret = %d\n",
2126                                  num, ret);
2127                         return ret;
2128                 }
2129                 /*
2130                  * 16-bit hex "?? 00" Little Endian looks like 8-bit hex "??"
2131                  */
2132                 feature_count = le16_to_cpu(desc->wCount);
2133                 if (type == FFS_OS_DESC_EXT_COMPAT &&
2134                     (feature_count > 255 || desc->Reserved))
2135                                 return -EINVAL;
2136                 len -= ret;
2137                 data += ret;
2138
2139                 /*
2140                  * Process all function/property descriptors
2141                  * of this Feature Descriptor
2142                  */
2143                 ret = ffs_do_single_os_desc(data, len, type,
2144                                             feature_count, entity, priv, desc);
2145                 if (unlikely(ret < 0)) {
2146                         pr_debug("%s returns %d\n", __func__, ret);
2147                         return ret;
2148                 }
2149
2150                 len -= ret;
2151                 data += ret;
2152         }
2153         return _len - len;
2154 }
2155
2156 /**
2157  * Validate contents of the buffer from userspace related to OS descriptors.
2158  */
2159 static int __ffs_data_do_os_desc(enum ffs_os_desc_type type,
2160                                  struct usb_os_desc_header *h, void *data,
2161                                  unsigned len, void *priv)
2162 {
2163         struct ffs_data *ffs = priv;
2164         u8 length;
2165
2166         ENTER();
2167
2168         switch (type) {
2169         case FFS_OS_DESC_EXT_COMPAT: {
2170                 struct usb_ext_compat_desc *d = data;
2171                 int i;
2172
2173                 if (len < sizeof(*d) ||
2174                     d->bFirstInterfaceNumber >= ffs->interfaces_count ||
2175                     !d->Reserved1)
2176                         return -EINVAL;
2177                 for (i = 0; i < ARRAY_SIZE(d->Reserved2); ++i)
2178                         if (d->Reserved2[i])
2179                                 return -EINVAL;
2180
2181                 length = sizeof(struct usb_ext_compat_desc);
2182         }
2183                 break;
2184         case FFS_OS_DESC_EXT_PROP: {
2185                 struct usb_ext_prop_desc *d = data;
2186                 u32 type, pdl;
2187                 u16 pnl;
2188
2189                 if (len < sizeof(*d) || h->interface >= ffs->interfaces_count)
2190                         return -EINVAL;
2191                 length = le32_to_cpu(d->dwSize);
2192                 type = le32_to_cpu(d->dwPropertyDataType);
2193                 if (type < USB_EXT_PROP_UNICODE ||
2194                     type > USB_EXT_PROP_UNICODE_MULTI) {
2195                         pr_vdebug("unsupported os descriptor property type: %d",
2196                                   type);
2197                         return -EINVAL;
2198                 }
2199                 pnl = le16_to_cpu(d->wPropertyNameLength);
2200                 pdl = le32_to_cpu(*(u32 *)((u8 *)data + 10 + pnl));
2201                 if (length != 14 + pnl + pdl) {
2202                         pr_vdebug("invalid os descriptor length: %d pnl:%d pdl:%d (descriptor %d)\n",
2203                                   length, pnl, pdl, type);
2204                         return -EINVAL;
2205                 }
2206                 ++ffs->ms_os_descs_ext_prop_count;
2207                 /* property name reported to the host as "WCHAR"s */
2208                 ffs->ms_os_descs_ext_prop_name_len += pnl * 2;
2209                 ffs->ms_os_descs_ext_prop_data_len += pdl;
2210         }
2211                 break;
2212         default:
2213                 pr_vdebug("unknown descriptor: %d\n", type);
2214                 return -EINVAL;
2215         }
2216         return length;
2217 }
2218
2219 static int __ffs_data_got_descs(struct ffs_data *ffs,
2220                                 char *const _data, size_t len)
2221 {
2222         char *data = _data, *raw_descs;
2223         unsigned os_descs_count = 0, counts[3], flags;
2224         int ret = -EINVAL, i;
2225         struct ffs_desc_helper helper;
2226
2227         ENTER();
2228
2229         if (get_unaligned_le32(data + 4) != len)
2230                 goto error;
2231
2232         switch (get_unaligned_le32(data)) {
2233         case FUNCTIONFS_DESCRIPTORS_MAGIC:
2234                 flags = FUNCTIONFS_HAS_FS_DESC | FUNCTIONFS_HAS_HS_DESC;
2235                 data += 8;
2236                 len  -= 8;
2237                 break;
2238         case FUNCTIONFS_DESCRIPTORS_MAGIC_V2:
2239                 flags = get_unaligned_le32(data + 8);
2240                 ffs->user_flags = flags;
2241                 if (flags & ~(FUNCTIONFS_HAS_FS_DESC |
2242                               FUNCTIONFS_HAS_HS_DESC |
2243                               FUNCTIONFS_HAS_SS_DESC |
2244                               FUNCTIONFS_HAS_MS_OS_DESC |
2245                               FUNCTIONFS_VIRTUAL_ADDR |
2246                               FUNCTIONFS_EVENTFD)) {
2247                         ret = -ENOSYS;
2248                         goto error;
2249                 }
2250                 data += 12;
2251                 len  -= 12;
2252                 break;
2253         default:
2254                 goto error;
2255         }
2256
2257         if (flags & FUNCTIONFS_EVENTFD) {
2258                 if (len < 4)
2259                         goto error;
2260                 ffs->ffs_eventfd =
2261                         eventfd_ctx_fdget((int)get_unaligned_le32(data));
2262                 if (IS_ERR(ffs->ffs_eventfd)) {
2263                         ret = PTR_ERR(ffs->ffs_eventfd);
2264                         ffs->ffs_eventfd = NULL;
2265                         goto error;
2266                 }
2267                 data += 4;
2268                 len  -= 4;
2269         }
2270
2271         /* Read fs_count, hs_count and ss_count (if present) */
2272         for (i = 0; i < 3; ++i) {
2273                 if (!(flags & (1 << i))) {
2274                         counts[i] = 0;
2275                 } else if (len < 4) {
2276                         goto error;
2277                 } else {
2278                         counts[i] = get_unaligned_le32(data);
2279                         data += 4;
2280                         len  -= 4;
2281                 }
2282         }
2283         if (flags & (1 << i)) {
2284                 os_descs_count = get_unaligned_le32(data);
2285                 data += 4;
2286                 len -= 4;
2287         };
2288
2289         /* Read descriptors */
2290         raw_descs = data;
2291         helper.ffs = ffs;
2292         for (i = 0; i < 3; ++i) {
2293                 if (!counts[i])
2294                         continue;
2295                 helper.interfaces_count = 0;
2296                 helper.eps_count = 0;
2297                 ret = ffs_do_descs(counts[i], data, len,
2298                                    __ffs_data_do_entity, &helper);
2299                 if (ret < 0)
2300                         goto error;
2301                 if (!ffs->eps_count && !ffs->interfaces_count) {
2302                         ffs->eps_count = helper.eps_count;
2303                         ffs->interfaces_count = helper.interfaces_count;
2304                 } else {
2305                         if (ffs->eps_count != helper.eps_count) {
2306                                 ret = -EINVAL;
2307                                 goto error;
2308                         }
2309                         if (ffs->interfaces_count != helper.interfaces_count) {
2310                                 ret = -EINVAL;
2311                                 goto error;
2312                         }
2313                 }
2314                 data += ret;
2315                 len  -= ret;
2316         }
2317         if (os_descs_count) {
2318                 ret = ffs_do_os_descs(os_descs_count, data, len,
2319                                       __ffs_data_do_os_desc, ffs);
2320                 if (ret < 0)
2321                         goto error;
2322                 data += ret;
2323                 len -= ret;
2324         }
2325
2326         if (raw_descs == data || len) {
2327                 ret = -EINVAL;
2328                 goto error;
2329         }
2330
2331         ffs->raw_descs_data     = _data;
2332         ffs->raw_descs          = raw_descs;
2333         ffs->raw_descs_length   = data - raw_descs;
2334         ffs->fs_descs_count     = counts[0];
2335         ffs->hs_descs_count     = counts[1];
2336         ffs->ss_descs_count     = counts[2];
2337         ffs->ms_os_descs_count  = os_descs_count;
2338
2339         return 0;
2340
2341 error:
2342         kfree(_data);
2343         return ret;
2344 }
2345
2346 static int __ffs_data_got_strings(struct ffs_data *ffs,
2347                                   char *const _data, size_t len)
2348 {
2349         u32 str_count, needed_count, lang_count;
2350         struct usb_gadget_strings **stringtabs, *t;
2351         const char *data = _data;
2352         struct usb_string *s;
2353
2354         ENTER();
2355
2356         if (unlikely(get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC ||
2357                      get_unaligned_le32(data + 4) != len))
2358                 goto error;
2359         str_count  = get_unaligned_le32(data + 8);
2360         lang_count = get_unaligned_le32(data + 12);
2361
2362         /* if one is zero the other must be zero */
2363         if (unlikely(!str_count != !lang_count))
2364                 goto error;
2365
2366         /* Do we have at least as many strings as descriptors need? */
2367         needed_count = ffs->strings_count;
2368         if (unlikely(str_count < needed_count))
2369                 goto error;
2370
2371         /*
2372          * If we don't need any strings just return and free all
2373          * memory.
2374          */
2375         if (!needed_count) {
2376                 kfree(_data);
2377                 return 0;
2378         }
2379
2380         /* Allocate everything in one chunk so there's less maintenance. */
2381         {
2382                 unsigned i = 0;
2383                 vla_group(d);
2384                 vla_item(d, struct usb_gadget_strings *, stringtabs,
2385                         lang_count + 1);
2386                 vla_item(d, struct usb_gadget_strings, stringtab, lang_count);
2387                 vla_item(d, struct usb_string, strings,
2388                         lang_count*(needed_count+1));
2389
2390                 char *vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
2391
2392                 if (unlikely(!vlabuf)) {
2393                         kfree(_data);
2394                         return -ENOMEM;
2395                 }
2396
2397                 /* Initialize the VLA pointers */
2398                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2399                 t = vla_ptr(vlabuf, d, stringtab);
2400                 i = lang_count;
2401                 do {
2402                         *stringtabs++ = t++;
2403                 } while (--i);
2404                 *stringtabs = NULL;
2405
2406                 /* stringtabs = vlabuf = d_stringtabs for later kfree */
2407                 stringtabs = vla_ptr(vlabuf, d, stringtabs);
2408                 t = vla_ptr(vlabuf, d, stringtab);
2409                 s = vla_ptr(vlabuf, d, strings);
2410         }
2411
2412         /* For each language */
2413         data += 16;
2414         len -= 16;
2415
2416         do { /* lang_count > 0 so we can use do-while */
2417                 unsigned needed = needed_count;
2418
2419                 if (unlikely(len < 3))
2420                         goto error_free;
2421                 t->language = get_unaligned_le16(data);
2422                 t->strings  = s;
2423                 ++t;
2424
2425                 data += 2;
2426                 len -= 2;
2427
2428                 /* For each string */
2429                 do { /* str_count > 0 so we can use do-while */
2430                         size_t length = strnlen(data, len);
2431
2432                         if (unlikely(length == len))
2433                                 goto error_free;
2434
2435                         /*
2436                          * User may provide more strings then we need,
2437                          * if that's the case we simply ignore the
2438                          * rest
2439                          */
2440                         if (likely(needed)) {
2441                                 /*
2442                                  * s->id will be set while adding
2443                                  * function to configuration so for
2444                                  * now just leave garbage here.
2445                                  */
2446                                 s->s = data;
2447                                 --needed;
2448                                 ++s;
2449                         }
2450
2451                         data += length + 1;
2452                         len -= length + 1;
2453                 } while (--str_count);
2454
2455                 s->id = 0;   /* terminator */
2456                 s->s = NULL;
2457                 ++s;
2458
2459         } while (--lang_count);
2460
2461         /* Some garbage left? */
2462         if (unlikely(len))
2463                 goto error_free;
2464
2465         /* Done! */
2466         ffs->stringtabs = stringtabs;
2467         ffs->raw_strings = _data;
2468
2469         return 0;
2470
2471 error_free:
2472         kfree(stringtabs);
2473 error:
2474         kfree(_data);
2475         return -EINVAL;
2476 }
2477
2478
2479 /* Events handling and management *******************************************/
2480
2481 static void __ffs_event_add(struct ffs_data *ffs,
2482                             enum usb_functionfs_event_type type)
2483 {
2484         enum usb_functionfs_event_type rem_type1, rem_type2 = type;
2485         int neg = 0;
2486
2487         /*
2488          * Abort any unhandled setup
2489          *
2490          * We do not need to worry about some cmpxchg() changing value
2491          * of ffs->setup_state without holding the lock because when
2492          * state is FFS_SETUP_PENDING cmpxchg() in several places in
2493          * the source does nothing.
2494          */
2495         if (ffs->setup_state == FFS_SETUP_PENDING)
2496                 ffs->setup_state = FFS_SETUP_CANCELLED;
2497
2498         /*
2499          * Logic of this function guarantees that there are at most four pending
2500          * evens on ffs->ev.types queue.  This is important because the queue
2501          * has space for four elements only and __ffs_ep0_read_events function
2502          * depends on that limit as well.  If more event types are added, those
2503          * limits have to be revisited or guaranteed to still hold.
2504          */
2505         switch (type) {
2506         case FUNCTIONFS_RESUME:
2507                 rem_type2 = FUNCTIONFS_SUSPEND;
2508                 /* FALL THROUGH */
2509         case FUNCTIONFS_SUSPEND:
2510         case FUNCTIONFS_SETUP:
2511                 rem_type1 = type;
2512                 /* Discard all similar events */
2513                 break;
2514
2515         case FUNCTIONFS_BIND:
2516         case FUNCTIONFS_UNBIND:
2517         case FUNCTIONFS_DISABLE:
2518         case FUNCTIONFS_ENABLE:
2519                 /* Discard everything other then power management. */
2520                 rem_type1 = FUNCTIONFS_SUSPEND;
2521                 rem_type2 = FUNCTIONFS_RESUME;
2522                 neg = 1;
2523                 break;
2524
2525         default:
2526                 WARN(1, "%d: unknown event, this should not happen\n", type);
2527                 return;
2528         }
2529
2530         {
2531                 u8 *ev  = ffs->ev.types, *out = ev;
2532                 unsigned n = ffs->ev.count;
2533                 for (; n; --n, ++ev)
2534                         if ((*ev == rem_type1 || *ev == rem_type2) == neg)
2535                                 *out++ = *ev;
2536                         else
2537                                 pr_vdebug("purging event %d\n", *ev);
2538                 ffs->ev.count = out - ffs->ev.types;
2539         }
2540
2541         pr_vdebug("adding event %d\n", type);
2542         ffs->ev.types[ffs->ev.count++] = type;
2543         wake_up_locked(&ffs->ev.waitq);
2544         if (ffs->ffs_eventfd)
2545                 eventfd_signal(ffs->ffs_eventfd, 1);
2546 }
2547
2548 static void ffs_event_add(struct ffs_data *ffs,
2549                           enum usb_functionfs_event_type type)
2550 {
2551         unsigned long flags;
2552         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
2553         __ffs_event_add(ffs, type);
2554         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
2555 }
2556
2557 /* Bind/unbind USB function hooks *******************************************/
2558
2559 static int ffs_ep_addr2idx(struct ffs_data *ffs, u8 endpoint_address)
2560 {
2561         int i;
2562
2563         for (i = 1; i < ARRAY_SIZE(ffs->eps_addrmap); ++i)
2564                 if (ffs->eps_addrmap[i] == endpoint_address)
2565                         return i;
2566         return -ENOENT;
2567 }
2568
2569 static int __ffs_func_bind_do_descs(enum ffs_entity_type type, u8 *valuep,
2570                                     struct usb_descriptor_header *desc,
2571                                     void *priv)
2572 {
2573         struct usb_endpoint_descriptor *ds = (void *)desc;
2574         struct ffs_function *func = priv;
2575         struct ffs_ep *ffs_ep;
2576         unsigned ep_desc_id;
2577         int idx;
2578         static const char *speed_names[] = { "full", "high", "super" };
2579
2580         if (type != FFS_DESCRIPTOR)
2581                 return 0;
2582
2583         /*
2584          * If ss_descriptors is not NULL, we are reading super speed
2585          * descriptors; if hs_descriptors is not NULL, we are reading high
2586          * speed descriptors; otherwise, we are reading full speed
2587          * descriptors.
2588          */
2589         if (func->function.ss_descriptors) {
2590                 ep_desc_id = 2;
2591                 func->function.ss_descriptors[(long)valuep] = desc;
2592         } else if (func->function.hs_descriptors) {
2593                 ep_desc_id = 1;
2594                 func->function.hs_descriptors[(long)valuep] = desc;
2595         } else {
2596                 ep_desc_id = 0;
2597                 func->function.fs_descriptors[(long)valuep]    = desc;
2598         }
2599
2600         if (!desc || desc->bDescriptorType != USB_DT_ENDPOINT)
2601                 return 0;
2602
2603         idx = ffs_ep_addr2idx(func->ffs, ds->bEndpointAddress) - 1;
2604         if (idx < 0)
2605                 return idx;
2606
2607         ffs_ep = func->eps + idx;
2608
2609         if (unlikely(ffs_ep->descs[ep_desc_id])) {
2610                 pr_err("two %sspeed descriptors for EP %d\n",
2611                           speed_names[ep_desc_id],
2612                           ds->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
2613                 return -EINVAL;
2614         }
2615         ffs_ep->descs[ep_desc_id] = ds;
2616
2617         ffs_dump_mem(": Original  ep desc", ds, ds->bLength);
2618         if (ffs_ep->ep) {
2619                 ds->bEndpointAddress = ffs_ep->descs[0]->bEndpointAddress;
2620                 if (!ds->wMaxPacketSize)
2621                         ds->wMaxPacketSize = ffs_ep->descs[0]->wMaxPacketSize;
2622         } else {
2623                 struct usb_request *req;
2624                 struct usb_ep *ep;
2625                 u8 bEndpointAddress;
2626
2627                 /*
2628                  * We back up bEndpointAddress because autoconfig overwrites
2629                  * it with physical endpoint address.
2630                  */
2631                 bEndpointAddress = ds->bEndpointAddress;
2632                 pr_vdebug("autoconfig\n");
2633                 ep = usb_ep_autoconfig(func->gadget, ds);
2634                 if (unlikely(!ep))
2635                         return -ENOTSUPP;
2636                 ep->driver_data = func->eps + idx;
2637
2638                 req = usb_ep_alloc_request(ep, GFP_KERNEL);
2639                 if (unlikely(!req))
2640                         return -ENOMEM;
2641
2642                 ffs_ep->ep  = ep;
2643                 ffs_ep->req = req;
2644                 func->eps_revmap[ds->bEndpointAddress &
2645                                  USB_ENDPOINT_NUMBER_MASK] = idx + 1;
2646                 /*
2647                  * If we use virtual address mapping, we restore
2648                  * original bEndpointAddress value.
2649                  */
2650                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
2651                         ds->bEndpointAddress = bEndpointAddress;
2652         }
2653         ffs_dump_mem(": Rewritten ep desc", ds, ds->bLength);
2654
2655         return 0;
2656 }
2657
2658 static int __ffs_func_bind_do_nums(enum ffs_entity_type type, u8 *valuep,
2659                                    struct usb_descriptor_header *desc,
2660                                    void *priv)
2661 {
2662         struct ffs_function *func = priv;
2663         unsigned idx;
2664         u8 newValue;
2665
2666         switch (type) {
2667         default:
2668         case FFS_DESCRIPTOR:
2669                 /* Handled in previous pass by __ffs_func_bind_do_descs() */
2670                 return 0;
2671
2672         case FFS_INTERFACE:
2673                 idx = *valuep;
2674                 if (func->interfaces_nums[idx] < 0) {
2675                         int id = usb_interface_id(func->conf, &func->function);
2676                         if (unlikely(id < 0))
2677                                 return id;
2678                         func->interfaces_nums[idx] = id;
2679                 }
2680                 newValue = func->interfaces_nums[idx];
2681                 break;
2682
2683         case FFS_STRING:
2684                 /* String' IDs are allocated when fsf_data is bound to cdev */
2685                 newValue = func->ffs->stringtabs[0]->strings[*valuep - 1].id;
2686                 break;
2687
2688         case FFS_ENDPOINT:
2689                 /*
2690                  * USB_DT_ENDPOINT are handled in
2691                  * __ffs_func_bind_do_descs().
2692                  */
2693                 if (desc->bDescriptorType == USB_DT_ENDPOINT)
2694                         return 0;
2695
2696                 idx = (*valuep & USB_ENDPOINT_NUMBER_MASK) - 1;
2697                 if (unlikely(!func->eps[idx].ep))
2698                         return -EINVAL;
2699
2700                 {
2701                         struct usb_endpoint_descriptor **descs;
2702                         descs = func->eps[idx].descs;
2703                         newValue = descs[descs[0] ? 0 : 1]->bEndpointAddress;
2704                 }
2705                 break;
2706         }
2707
2708         pr_vdebug("%02x -> %02x\n", *valuep, newValue);
2709         *valuep = newValue;
2710         return 0;
2711 }
2712
2713 static int __ffs_func_bind_do_os_desc(enum ffs_os_desc_type type,
2714                                       struct usb_os_desc_header *h, void *data,
2715                                       unsigned len, void *priv)
2716 {
2717         struct ffs_function *func = priv;
2718         u8 length = 0;
2719
2720         switch (type) {
2721         case FFS_OS_DESC_EXT_COMPAT: {
2722                 struct usb_ext_compat_desc *desc = data;
2723                 struct usb_os_desc_table *t;
2724
2725                 t = &func->function.os_desc_table[desc->bFirstInterfaceNumber];
2726                 t->if_id = func->interfaces_nums[desc->bFirstInterfaceNumber];
2727                 memcpy(t->os_desc->ext_compat_id, &desc->CompatibleID,
2728                        ARRAY_SIZE(desc->CompatibleID) +
2729                        ARRAY_SIZE(desc->SubCompatibleID));
2730                 length = sizeof(*desc);
2731         }
2732                 break;
2733         case FFS_OS_DESC_EXT_PROP: {
2734                 struct usb_ext_prop_desc *desc = data;
2735                 struct usb_os_desc_table *t;
2736                 struct usb_os_desc_ext_prop *ext_prop;
2737                 char *ext_prop_name;
2738                 char *ext_prop_data;
2739
2740                 t = &func->function.os_desc_table[h->interface];
2741                 t->if_id = func->interfaces_nums[h->interface];
2742
2743                 ext_prop = func->ffs->ms_os_descs_ext_prop_avail;
2744                 func->ffs->ms_os_descs_ext_prop_avail += sizeof(*ext_prop);
2745
2746                 ext_prop->type = le32_to_cpu(desc->dwPropertyDataType);
2747                 ext_prop->name_len = le16_to_cpu(desc->wPropertyNameLength);
2748                 ext_prop->data_len = le32_to_cpu(*(u32 *)
2749                         usb_ext_prop_data_len_ptr(data, ext_prop->name_len));
2750                 length = ext_prop->name_len + ext_prop->data_len + 14;
2751
2752                 ext_prop_name = func->ffs->ms_os_descs_ext_prop_name_avail;
2753                 func->ffs->ms_os_descs_ext_prop_name_avail +=
2754                         ext_prop->name_len;
2755
2756                 ext_prop_data = func->ffs->ms_os_descs_ext_prop_data_avail;
2757                 func->ffs->ms_os_descs_ext_prop_data_avail +=
2758                         ext_prop->data_len;
2759                 memcpy(ext_prop_data,
2760                        usb_ext_prop_data_ptr(data, ext_prop->name_len),
2761                        ext_prop->data_len);
2762                 /* unicode data reported to the host as "WCHAR"s */
2763                 switch (ext_prop->type) {
2764                 case USB_EXT_PROP_UNICODE:
2765                 case USB_EXT_PROP_UNICODE_ENV:
2766                 case USB_EXT_PROP_UNICODE_LINK:
2767                 case USB_EXT_PROP_UNICODE_MULTI:
2768                         ext_prop->data_len *= 2;
2769                         break;
2770                 }
2771                 ext_prop->data = ext_prop_data;
2772
2773                 memcpy(ext_prop_name, usb_ext_prop_name_ptr(data),
2774                        ext_prop->name_len);
2775                 /* property name reported to the host as "WCHAR"s */
2776                 ext_prop->name_len *= 2;
2777                 ext_prop->name = ext_prop_name;
2778
2779                 t->os_desc->ext_prop_len +=
2780                         ext_prop->name_len + ext_prop->data_len + 14;
2781                 ++t->os_desc->ext_prop_count;
2782                 list_add_tail(&ext_prop->entry, &t->os_desc->ext_prop);
2783         }
2784                 break;
2785         default:
2786                 pr_vdebug("unknown descriptor: %d\n", type);
2787         }
2788
2789         return length;
2790 }
2791
2792 static inline struct f_fs_opts *ffs_do_functionfs_bind(struct usb_function *f,
2793                                                 struct usb_configuration *c)
2794 {
2795         struct ffs_function *func = ffs_func_from_usb(f);
2796         struct f_fs_opts *ffs_opts =
2797                 container_of(f->fi, struct f_fs_opts, func_inst);
2798         int ret;
2799
2800         ENTER();
2801
2802         /*
2803          * Legacy gadget triggers binding in functionfs_ready_callback,
2804          * which already uses locking; taking the same lock here would
2805          * cause a deadlock.
2806          *
2807          * Configfs-enabled gadgets however do need ffs_dev_lock.
2808          */
2809         if (!ffs_opts->no_configfs)
2810                 ffs_dev_lock();
2811         ret = ffs_opts->dev->desc_ready ? 0 : -ENODEV;
2812         func->ffs = ffs_opts->dev->ffs_data;
2813         if (!ffs_opts->no_configfs)
2814                 ffs_dev_unlock();
2815         if (ret)
2816                 return ERR_PTR(ret);
2817
2818         func->conf = c;
2819         func->gadget = c->cdev->gadget;
2820
2821         /*
2822          * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
2823          * configurations are bound in sequence with list_for_each_entry,
2824          * in each configuration its functions are bound in sequence
2825          * with list_for_each_entry, so we assume no race condition
2826          * with regard to ffs_opts->bound access
2827          */
2828         if (!ffs_opts->refcnt) {
2829                 ret = functionfs_bind(func->ffs, c->cdev);
2830                 if (ret)
2831                         return ERR_PTR(ret);
2832         }
2833         ffs_opts->refcnt++;
2834         func->function.strings = func->ffs->stringtabs;
2835
2836         return ffs_opts;
2837 }
2838
2839 static int _ffs_func_bind(struct usb_configuration *c,
2840                           struct usb_function *f)
2841 {
2842         struct ffs_function *func = ffs_func_from_usb(f);
2843         struct ffs_data *ffs = func->ffs;
2844
2845         const int full = !!func->ffs->fs_descs_count;
2846         const int high = gadget_is_dualspeed(func->gadget) &&
2847                 func->ffs->hs_descs_count;
2848         const int super = gadget_is_superspeed(func->gadget) &&
2849                 func->ffs->ss_descs_count;
2850
2851         int fs_len, hs_len, ss_len, ret, i;
2852         struct ffs_ep *eps_ptr;
2853
2854         /* Make it a single chunk, less management later on */
2855         vla_group(d);
2856         vla_item_with_sz(d, struct ffs_ep, eps, ffs->eps_count);
2857         vla_item_with_sz(d, struct usb_descriptor_header *, fs_descs,
2858                 full ? ffs->fs_descs_count + 1 : 0);
2859         vla_item_with_sz(d, struct usb_descriptor_header *, hs_descs,
2860                 high ? ffs->hs_descs_count + 1 : 0);
2861         vla_item_with_sz(d, struct usb_descriptor_header *, ss_descs,
2862                 super ? ffs->ss_descs_count + 1 : 0);
2863         vla_item_with_sz(d, short, inums, ffs->interfaces_count);
2864         vla_item_with_sz(d, struct usb_os_desc_table, os_desc_table,
2865                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
2866         vla_item_with_sz(d, char[16], ext_compat,
2867                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
2868         vla_item_with_sz(d, struct usb_os_desc, os_desc,
2869                          c->cdev->use_os_string ? ffs->interfaces_count : 0);
2870         vla_item_with_sz(d, struct usb_os_desc_ext_prop, ext_prop,
2871                          ffs->ms_os_descs_ext_prop_count);
2872         vla_item_with_sz(d, char, ext_prop_name,
2873                          ffs->ms_os_descs_ext_prop_name_len);
2874         vla_item_with_sz(d, char, ext_prop_data,
2875                          ffs->ms_os_descs_ext_prop_data_len);
2876         vla_item_with_sz(d, char, raw_descs, ffs->raw_descs_length);
2877         char *vlabuf;
2878
2879         ENTER();
2880
2881         /* Has descriptors only for speeds gadget does not support */
2882         if (unlikely(!(full | high | super)))
2883                 return -ENOTSUPP;
2884
2885         /* Allocate a single chunk, less management later on */
2886         vlabuf = kzalloc(vla_group_size(d), GFP_KERNEL);
2887         if (unlikely(!vlabuf))
2888                 return -ENOMEM;
2889
2890         ffs->ms_os_descs_ext_prop_avail = vla_ptr(vlabuf, d, ext_prop);
2891         ffs->ms_os_descs_ext_prop_name_avail =
2892                 vla_ptr(vlabuf, d, ext_prop_name);
2893         ffs->ms_os_descs_ext_prop_data_avail =
2894                 vla_ptr(vlabuf, d, ext_prop_data);
2895
2896         /* Copy descriptors  */
2897         memcpy(vla_ptr(vlabuf, d, raw_descs), ffs->raw_descs,
2898                ffs->raw_descs_length);
2899
2900         memset(vla_ptr(vlabuf, d, inums), 0xff, d_inums__sz);
2901         eps_ptr = vla_ptr(vlabuf, d, eps);
2902         for (i = 0; i < ffs->eps_count; i++)
2903                 eps_ptr[i].num = -1;
2904
2905         /* Save pointers
2906          * d_eps == vlabuf, func->eps used to kfree vlabuf later
2907         */
2908         func->eps             = vla_ptr(vlabuf, d, eps);
2909         func->interfaces_nums = vla_ptr(vlabuf, d, inums);
2910
2911         /*
2912          * Go through all the endpoint descriptors and allocate
2913          * endpoints first, so that later we can rewrite the endpoint
2914          * numbers without worrying that it may be described later on.
2915          */
2916         if (likely(full)) {
2917                 func->function.fs_descriptors = vla_ptr(vlabuf, d, fs_descs);
2918                 fs_len = ffs_do_descs(ffs->fs_descs_count,
2919                                       vla_ptr(vlabuf, d, raw_descs),
2920                                       d_raw_descs__sz,
2921                                       __ffs_func_bind_do_descs, func);
2922                 if (unlikely(fs_len < 0)) {
2923                         ret = fs_len;
2924                         goto error;
2925                 }
2926         } else {
2927                 fs_len = 0;
2928         }
2929
2930         if (likely(high)) {
2931                 func->function.hs_descriptors = vla_ptr(vlabuf, d, hs_descs);
2932                 hs_len = ffs_do_descs(ffs->hs_descs_count,
2933                                       vla_ptr(vlabuf, d, raw_descs) + fs_len,
2934                                       d_raw_descs__sz - fs_len,
2935                                       __ffs_func_bind_do_descs, func);
2936                 if (unlikely(hs_len < 0)) {
2937                         ret = hs_len;
2938                         goto error;
2939                 }
2940         } else {
2941                 hs_len = 0;
2942         }
2943
2944         if (likely(super)) {
2945                 func->function.ss_descriptors = vla_ptr(vlabuf, d, ss_descs);
2946                 ss_len = ffs_do_descs(ffs->ss_descs_count,
2947                                 vla_ptr(vlabuf, d, raw_descs) + fs_len + hs_len,
2948                                 d_raw_descs__sz - fs_len - hs_len,
2949                                 __ffs_func_bind_do_descs, func);
2950                 if (unlikely(ss_len < 0)) {
2951                         ret = ss_len;
2952                         goto error;
2953                 }
2954         } else {
2955                 ss_len = 0;
2956         }
2957
2958         /*
2959          * Now handle interface numbers allocation and interface and
2960          * endpoint numbers rewriting.  We can do that in one go
2961          * now.
2962          */
2963         ret = ffs_do_descs(ffs->fs_descs_count +
2964                            (high ? ffs->hs_descs_count : 0) +
2965                            (super ? ffs->ss_descs_count : 0),
2966                            vla_ptr(vlabuf, d, raw_descs), d_raw_descs__sz,
2967                            __ffs_func_bind_do_nums, func);
2968         if (unlikely(ret < 0))
2969                 goto error;
2970
2971         func->function.os_desc_table = vla_ptr(vlabuf, d, os_desc_table);
2972         if (c->cdev->use_os_string) {
2973                 for (i = 0; i < ffs->interfaces_count; ++i) {
2974                         struct usb_os_desc *desc;
2975
2976                         desc = func->function.os_desc_table[i].os_desc =
2977                                 vla_ptr(vlabuf, d, os_desc) +
2978                                 i * sizeof(struct usb_os_desc);
2979                         desc->ext_compat_id =
2980                                 vla_ptr(vlabuf, d, ext_compat) + i * 16;
2981                         INIT_LIST_HEAD(&desc->ext_prop);
2982                 }
2983                 ret = ffs_do_os_descs(ffs->ms_os_descs_count,
2984                                       vla_ptr(vlabuf, d, raw_descs) +
2985                                       fs_len + hs_len + ss_len,
2986                                       d_raw_descs__sz - fs_len - hs_len -
2987                                       ss_len,
2988                                       __ffs_func_bind_do_os_desc, func);
2989                 if (unlikely(ret < 0))
2990                         goto error;
2991         }
2992         func->function.os_desc_n =
2993                 c->cdev->use_os_string ? ffs->interfaces_count : 0;
2994
2995         /* And we're done */
2996         ffs_event_add(ffs, FUNCTIONFS_BIND);
2997         return 0;
2998
2999 error:
3000         /* XXX Do we need to release all claimed endpoints here? */
3001         return ret;
3002 }
3003
3004 static int ffs_func_bind(struct usb_configuration *c,
3005                          struct usb_function *f)
3006 {
3007         struct f_fs_opts *ffs_opts = ffs_do_functionfs_bind(f, c);
3008         struct ffs_function *func = ffs_func_from_usb(f);
3009         int ret;
3010
3011         if (IS_ERR(ffs_opts))
3012                 return PTR_ERR(ffs_opts);
3013
3014         ret = _ffs_func_bind(c, f);
3015         if (ret && !--ffs_opts->refcnt)
3016                 functionfs_unbind(func->ffs);
3017
3018         return ret;
3019 }
3020
3021
3022 /* Other USB function hooks *************************************************/
3023
3024 static void ffs_reset_work(struct work_struct *work)
3025 {
3026         struct ffs_data *ffs = container_of(work,
3027                 struct ffs_data, reset_work);
3028         ffs_data_reset(ffs);
3029 }
3030
3031 static int ffs_func_set_alt(struct usb_function *f,
3032                             unsigned interface, unsigned alt)
3033 {
3034         struct ffs_function *func = ffs_func_from_usb(f);
3035         struct ffs_data *ffs = func->ffs;
3036         int ret = 0, intf;
3037
3038         if (alt != (unsigned)-1) {
3039                 intf = ffs_func_revmap_intf(func, interface);
3040                 if (unlikely(intf < 0))
3041                         return intf;
3042         }
3043
3044         if (ffs->func)
3045                 ffs_func_eps_disable(ffs->func);
3046
3047         if (ffs->state == FFS_DEACTIVATED) {
3048                 ffs->state = FFS_CLOSING;
3049                 INIT_WORK(&ffs->reset_work, ffs_reset_work);
3050                 schedule_work(&ffs->reset_work);
3051                 return -ENODEV;
3052         }
3053
3054         if (ffs->state != FFS_ACTIVE)
3055                 return -ENODEV;
3056
3057         if (alt == (unsigned)-1) {
3058                 ffs->func = NULL;
3059                 ffs_event_add(ffs, FUNCTIONFS_DISABLE);
3060                 return 0;
3061         }
3062
3063         ffs->func = func;
3064         ret = ffs_func_eps_enable(func);
3065         if (likely(ret >= 0))
3066                 ffs_event_add(ffs, FUNCTIONFS_ENABLE);
3067         return ret;
3068 }
3069
3070 static void ffs_func_disable(struct usb_function *f)
3071 {
3072         ffs_func_set_alt(f, 0, (unsigned)-1);
3073 }
3074
3075 static int ffs_func_setup(struct usb_function *f,
3076                           const struct usb_ctrlrequest *creq)
3077 {
3078         struct ffs_function *func = ffs_func_from_usb(f);
3079         struct ffs_data *ffs = func->ffs;
3080         unsigned long flags;
3081         int ret;
3082
3083         ENTER();
3084
3085         pr_vdebug("creq->bRequestType = %02x\n", creq->bRequestType);
3086         pr_vdebug("creq->bRequest     = %02x\n", creq->bRequest);
3087         pr_vdebug("creq->wValue       = %04x\n", le16_to_cpu(creq->wValue));
3088         pr_vdebug("creq->wIndex       = %04x\n", le16_to_cpu(creq->wIndex));
3089         pr_vdebug("creq->wLength      = %04x\n", le16_to_cpu(creq->wLength));
3090
3091         /*
3092          * Most requests directed to interface go through here
3093          * (notable exceptions are set/get interface) so we need to
3094          * handle them.  All other either handled by composite or
3095          * passed to usb_configuration->setup() (if one is set).  No
3096          * matter, we will handle requests directed to endpoint here
3097          * as well (as it's straightforward) but what to do with any
3098          * other request?
3099          */
3100         if (ffs->state != FFS_ACTIVE)
3101                 return -ENODEV;
3102
3103         switch (creq->bRequestType & USB_RECIP_MASK) {
3104         case USB_RECIP_INTERFACE:
3105                 ret = ffs_func_revmap_intf(func, le16_to_cpu(creq->wIndex));
3106                 if (unlikely(ret < 0))
3107                         return ret;
3108                 break;
3109
3110         case USB_RECIP_ENDPOINT:
3111                 ret = ffs_func_revmap_ep(func, le16_to_cpu(creq->wIndex));
3112                 if (unlikely(ret < 0))
3113                         return ret;
3114                 if (func->ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
3115                         ret = func->ffs->eps_addrmap[ret];
3116                 break;
3117
3118         default:
3119                 return -EOPNOTSUPP;
3120         }
3121
3122         spin_lock_irqsave(&ffs->ev.waitq.lock, flags);
3123         ffs->ev.setup = *creq;
3124         ffs->ev.setup.wIndex = cpu_to_le16(ret);
3125         __ffs_event_add(ffs, FUNCTIONFS_SETUP);
3126         spin_unlock_irqrestore(&ffs->ev.waitq.lock, flags);
3127
3128         return 0;
3129 }
3130
3131 static void ffs_func_suspend(struct usb_function *f)
3132 {
3133         ENTER();
3134         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_SUSPEND);
3135 }
3136
3137 static void ffs_func_resume(struct usb_function *f)
3138 {
3139         ENTER();
3140         ffs_event_add(ffs_func_from_usb(f)->ffs, FUNCTIONFS_RESUME);
3141 }
3142
3143
3144 /* Endpoint and interface numbers reverse mapping ***************************/
3145
3146 static int ffs_func_revmap_ep(struct ffs_function *func, u8 num)
3147 {
3148         num = func->eps_revmap[num & USB_ENDPOINT_NUMBER_MASK];
3149         return num ? num : -EDOM;
3150 }
3151
3152 static int ffs_func_revmap_intf(struct ffs_function *func, u8 intf)
3153 {
3154         short *nums = func->interfaces_nums;
3155         unsigned count = func->ffs->interfaces_count;
3156
3157         for (; count; --count, ++nums) {
3158                 if (*nums >= 0 && *nums == intf)
3159                         return nums - func->interfaces_nums;
3160         }
3161
3162         return -EDOM;
3163 }
3164
3165
3166 /* Devices management *******************************************************/
3167
3168 static LIST_HEAD(ffs_devices);
3169
3170 static struct ffs_dev *_ffs_do_find_dev(const char *name)
3171 {
3172         struct ffs_dev *dev;
3173
3174         list_for_each_entry(dev, &ffs_devices, entry) {
3175                 if (!dev->name || !name)
3176                         continue;
3177                 if (strcmp(dev->name, name) == 0)
3178                         return dev;
3179         }
3180
3181         return NULL;
3182 }
3183
3184 /*
3185  * ffs_lock must be taken by the caller of this function
3186  */
3187 static struct ffs_dev *_ffs_get_single_dev(void)
3188 {
3189         struct ffs_dev *dev;
3190
3191         if (list_is_singular(&ffs_devices)) {
3192                 dev = list_first_entry(&ffs_devices, struct ffs_dev, entry);
3193                 if (dev->single)
3194                         return dev;
3195         }
3196
3197         return NULL;
3198 }
3199
3200 /*
3201  * ffs_lock must be taken by the caller of this function
3202  */
3203 static struct ffs_dev *_ffs_find_dev(const char *name)
3204 {
3205         struct ffs_dev *dev;
3206
3207         dev = _ffs_get_single_dev();
3208         if (dev)
3209                 return dev;
3210
3211         return _ffs_do_find_dev(name);
3212 }
3213
3214 /* Configfs support *********************************************************/
3215
3216 static inline struct f_fs_opts *to_ffs_opts(struct config_item *item)
3217 {
3218         return container_of(to_config_group(item), struct f_fs_opts,
3219                             func_inst.group);
3220 }
3221
3222 static void ffs_attr_release(struct config_item *item)
3223 {
3224         struct f_fs_opts *opts = to_ffs_opts(item);
3225
3226         usb_put_function_instance(&opts->func_inst);
3227 }
3228
3229 static struct configfs_item_operations ffs_item_ops = {
3230         .release        = ffs_attr_release,
3231 };
3232
3233 static struct config_item_type ffs_func_type = {
3234         .ct_item_ops    = &ffs_item_ops,
3235         .ct_owner       = THIS_MODULE,
3236 };
3237
3238
3239 /* Function registration interface ******************************************/
3240
3241 static void ffs_free_inst(struct usb_function_instance *f)
3242 {
3243         struct f_fs_opts *opts;
3244
3245         opts = to_f_fs_opts(f);
3246         ffs_dev_lock();
3247         _ffs_free_dev(opts->dev);
3248         ffs_dev_unlock();
3249         kfree(opts);
3250 }
3251
3252 #define MAX_INST_NAME_LEN       40
3253
3254 static int ffs_set_inst_name(struct usb_function_instance *fi, const char *name)
3255 {
3256         struct f_fs_opts *opts;
3257         char *ptr;
3258         const char *tmp;
3259         int name_len, ret;
3260
3261         name_len = strlen(name) + 1;
3262         if (name_len > MAX_INST_NAME_LEN)
3263                 return -ENAMETOOLONG;
3264
3265         ptr = kstrndup(name, name_len, GFP_KERNEL);
3266         if (!ptr)
3267                 return -ENOMEM;
3268
3269         opts = to_f_fs_opts(fi);
3270         tmp = NULL;
3271
3272         ffs_dev_lock();
3273
3274         tmp = opts->dev->name_allocated ? opts->dev->name : NULL;
3275         ret = _ffs_name_dev(opts->dev, ptr);
3276         if (ret) {
3277                 kfree(ptr);
3278                 ffs_dev_unlock();
3279                 return ret;
3280         }
3281         opts->dev->name_allocated = true;
3282
3283         ffs_dev_unlock();
3284
3285         kfree(tmp);
3286
3287         return 0;
3288 }
3289
3290 static struct usb_function_instance *ffs_alloc_inst(void)
3291 {
3292         struct f_fs_opts *opts;
3293         struct ffs_dev *dev;
3294
3295         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
3296         if (!opts)
3297                 return ERR_PTR(-ENOMEM);
3298
3299         opts->func_inst.set_inst_name = ffs_set_inst_name;
3300         opts->func_inst.free_func_inst = ffs_free_inst;
3301         ffs_dev_lock();
3302         dev = _ffs_alloc_dev();
3303         ffs_dev_unlock();
3304         if (IS_ERR(dev)) {
3305                 kfree(opts);
3306                 return ERR_CAST(dev);
3307         }
3308         opts->dev = dev;
3309         dev->opts = opts;
3310
3311         config_group_init_type_name(&opts->func_inst.group, "",
3312                                     &ffs_func_type);
3313         return &opts->func_inst;
3314 }
3315
3316 static void ffs_free(struct usb_function *f)
3317 {
3318         kfree(ffs_func_from_usb(f));
3319 }
3320
3321 static void ffs_func_unbind(struct usb_configuration *c,
3322                             struct usb_function *f)
3323 {
3324         struct ffs_function *func = ffs_func_from_usb(f);
3325         struct ffs_data *ffs = func->ffs;
3326         struct f_fs_opts *opts =
3327                 container_of(f->fi, struct f_fs_opts, func_inst);
3328         struct ffs_ep *ep = func->eps;
3329         unsigned count = ffs->eps_count;
3330         unsigned long flags;
3331
3332         ENTER();
3333         if (ffs->func == func) {
3334                 ffs_func_eps_disable(func);
3335                 ffs->func = NULL;
3336         }
3337
3338         if (!--opts->refcnt)
3339                 functionfs_unbind(ffs);
3340
3341         /* cleanup after autoconfig */
3342         spin_lock_irqsave(&func->ffs->eps_lock, flags);
3343         do {
3344                 if (ep->ep && ep->req)
3345                         usb_ep_free_request(ep->ep, ep->req);
3346                 ep->req = NULL;
3347                 ++ep;
3348         } while (--count);
3349         spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
3350         kfree(func->eps);
3351         func->eps = NULL;
3352         /*
3353          * eps, descriptors and interfaces_nums are allocated in the
3354          * same chunk so only one free is required.
3355          */
3356         func->function.fs_descriptors = NULL;
3357         func->function.hs_descriptors = NULL;
3358         func->function.ss_descriptors = NULL;
3359         func->interfaces_nums = NULL;
3360
3361         ffs_event_add(ffs, FUNCTIONFS_UNBIND);
3362 }
3363
3364 static struct usb_function *ffs_alloc(struct usb_function_instance *fi)
3365 {
3366         struct ffs_function *func;
3367
3368         ENTER();
3369
3370         func = kzalloc(sizeof(*func), GFP_KERNEL);
3371         if (unlikely(!func))
3372                 return ERR_PTR(-ENOMEM);
3373
3374         func->function.name    = "Function FS Gadget";
3375
3376         func->function.bind    = ffs_func_bind;
3377         func->function.unbind  = ffs_func_unbind;
3378         func->function.set_alt = ffs_func_set_alt;
3379         func->function.disable = ffs_func_disable;
3380         func->function.setup   = ffs_func_setup;
3381         func->function.suspend = ffs_func_suspend;
3382         func->function.resume  = ffs_func_resume;
3383         func->function.free_func = ffs_free;
3384
3385         return &func->function;
3386 }
3387
3388 /*
3389  * ffs_lock must be taken by the caller of this function
3390  */
3391 static struct ffs_dev *_ffs_alloc_dev(void)
3392 {
3393         struct ffs_dev *dev;
3394         int ret;
3395
3396         if (_ffs_get_single_dev())
3397                         return ERR_PTR(-EBUSY);
3398
3399         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3400         if (!dev)
3401                 return ERR_PTR(-ENOMEM);
3402
3403         if (list_empty(&ffs_devices)) {
3404                 ret = functionfs_init();
3405                 if (ret) {
3406                         kfree(dev);
3407                         return ERR_PTR(ret);
3408                 }
3409         }
3410
3411         list_add(&dev->entry, &ffs_devices);
3412
3413         return dev;
3414 }
3415
3416 /*
3417  * ffs_lock must be taken by the caller of this function
3418  * The caller is responsible for "name" being available whenever f_fs needs it
3419  */
3420 static int _ffs_name_dev(struct ffs_dev *dev, const char *name)
3421 {
3422         struct ffs_dev *existing;
3423
3424         existing = _ffs_do_find_dev(name);
3425         if (existing)
3426                 return -EBUSY;
3427
3428         dev->name = name;
3429
3430         return 0;
3431 }
3432
3433 /*
3434  * The caller is responsible for "name" being available whenever f_fs needs it
3435  */
3436 int ffs_name_dev(struct ffs_dev *dev, const char *name)
3437 {
3438         int ret;
3439
3440         ffs_dev_lock();
3441         ret = _ffs_name_dev(dev, name);
3442         ffs_dev_unlock();
3443
3444         return ret;
3445 }
3446 EXPORT_SYMBOL_GPL(ffs_name_dev);
3447
3448 int ffs_single_dev(struct ffs_dev *dev)
3449 {
3450         int ret;
3451
3452         ret = 0;
3453         ffs_dev_lock();
3454
3455         if (!list_is_singular(&ffs_devices))
3456                 ret = -EBUSY;
3457         else
3458                 dev->single = true;
3459
3460         ffs_dev_unlock();
3461         return ret;
3462 }
3463 EXPORT_SYMBOL_GPL(ffs_single_dev);
3464
3465 /*
3466  * ffs_lock must be taken by the caller of this function
3467  */
3468 static void _ffs_free_dev(struct ffs_dev *dev)
3469 {
3470         list_del(&dev->entry);
3471         if (dev->name_allocated)
3472                 kfree(dev->name);
3473         kfree(dev);
3474         if (list_empty(&ffs_devices))
3475                 functionfs_cleanup();
3476 }
3477
3478 static void *ffs_acquire_dev(const char *dev_name)
3479 {
3480         struct ffs_dev *ffs_dev;
3481
3482         ENTER();
3483         ffs_dev_lock();
3484
3485         ffs_dev = _ffs_find_dev(dev_name);
3486         if (!ffs_dev)
3487                 ffs_dev = ERR_PTR(-ENOENT);
3488         else if (ffs_dev->mounted)
3489                 ffs_dev = ERR_PTR(-EBUSY);
3490         else if (ffs_dev->ffs_acquire_dev_callback &&
3491             ffs_dev->ffs_acquire_dev_callback(ffs_dev))
3492                 ffs_dev = ERR_PTR(-ENOENT);
3493         else
3494                 ffs_dev->mounted = true;
3495
3496         ffs_dev_unlock();
3497         return ffs_dev;
3498 }
3499
3500 static void ffs_release_dev(struct ffs_data *ffs_data)
3501 {
3502         struct ffs_dev *ffs_dev;
3503
3504         ENTER();
3505         ffs_dev_lock();
3506
3507         ffs_dev = ffs_data->private_data;
3508         if (ffs_dev) {
3509                 ffs_dev->mounted = false;
3510
3511                 if (ffs_dev->ffs_release_dev_callback)
3512                         ffs_dev->ffs_release_dev_callback(ffs_dev);
3513         }
3514
3515         ffs_dev_unlock();
3516 }
3517
3518 static int ffs_ready(struct ffs_data *ffs)
3519 {
3520         struct ffs_dev *ffs_obj;
3521         int ret = 0;
3522
3523         ENTER();
3524         ffs_dev_lock();
3525
3526         ffs_obj = ffs->private_data;
3527         if (!ffs_obj) {
3528                 ret = -EINVAL;
3529                 goto done;
3530         }
3531         if (WARN_ON(ffs_obj->desc_ready)) {
3532                 ret = -EBUSY;
3533                 goto done;
3534         }
3535
3536         ffs_obj->desc_ready = true;
3537         ffs_obj->ffs_data = ffs;
3538
3539         if (ffs_obj->ffs_ready_callback) {
3540                 ret = ffs_obj->ffs_ready_callback(ffs);
3541                 if (ret)
3542                         goto done;
3543         }
3544
3545         set_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags);
3546 done:
3547         ffs_dev_unlock();
3548         return ret;
3549 }
3550
3551 static void ffs_closed(struct ffs_data *ffs)
3552 {
3553         struct ffs_dev *ffs_obj;
3554         struct f_fs_opts *opts;
3555
3556         ENTER();
3557         ffs_dev_lock();
3558
3559         ffs_obj = ffs->private_data;
3560         if (!ffs_obj)
3561                 goto done;
3562
3563         ffs_obj->desc_ready = false;
3564
3565         if (test_and_clear_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags) &&
3566             ffs_obj->ffs_closed_callback)
3567                 ffs_obj->ffs_closed_callback(ffs);
3568
3569         if (ffs_obj->opts)
3570                 opts = ffs_obj->opts;
3571         else
3572                 goto done;
3573
3574         if (opts->no_configfs || !opts->func_inst.group.cg_item.ci_parent
3575             || !atomic_read(&opts->func_inst.group.cg_item.ci_kref.refcount))
3576                 goto done;
3577
3578         unregister_gadget_item(ffs_obj->opts->
3579                                func_inst.group.cg_item.ci_parent->ci_parent);
3580 done:
3581         ffs_dev_unlock();
3582 }
3583
3584 /* Misc helper functions ****************************************************/
3585
3586 static int ffs_mutex_lock(struct mutex *mutex, unsigned nonblock)
3587 {
3588         return nonblock
3589                 ? likely(mutex_trylock(mutex)) ? 0 : -EAGAIN
3590                 : mutex_lock_interruptible(mutex);
3591 }
3592
3593 static char *ffs_prepare_buffer(const char __user *buf, size_t len)
3594 {
3595         char *data;
3596
3597         if (unlikely(!len))
3598                 return NULL;
3599
3600         data = kmalloc(len, GFP_KERNEL);
3601         if (unlikely(!data))
3602                 return ERR_PTR(-ENOMEM);
3603
3604         if (unlikely(copy_from_user(data, buf, len))) {
3605                 kfree(data);
3606                 return ERR_PTR(-EFAULT);
3607         }
3608
3609         pr_vdebug("Buffer from user space:\n");
3610         ffs_dump_mem("", data, len);
3611
3612         return data;
3613 }
3614
3615 DECLARE_USB_FUNCTION_INIT(ffs, ffs_alloc_inst, ffs_alloc);
3616 MODULE_LICENSE("GPL");
3617 MODULE_AUTHOR("Michal Nazarewicz");