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