drivers/infiniband/core/fmr_pool.c

   1 /*
   2  * Copyright (c) 2004 Topspin Communications.  All rights reserved.
   3  *
   4  * This software is available to you under a choice of one of two
   5  * licenses.  You may choose to be licensed under the terms of the GNU
   6  * General Public License (GPL) Version 2, available from the file
   7  * COPYING in the main directory of this source tree, or the
   8  * OpenIB.org BSD license below:
   9  *
  10  *     Redistribution and use in source and binary forms, with or
  11  *     without modification, are permitted provided that the following
  12  *     conditions are met:
  13  *
  14  *      - Redistributions of source code must retain the above
  15  *        copyright notice, this list of conditions and the following
  16  *        disclaimer.
  17  *
  18  *      - Redistributions in binary form must reproduce the above
  19  *        copyright notice, this list of conditions and the following
  20  *        disclaimer in the documentation and/or other materials
  21  *        provided with the distribution.
  22  *
  23  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  24  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  25  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  26  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  27  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  28  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  29  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  30  * SOFTWARE.
  31  *
  32  * $Id: fmr_pool.c 1349 2004-12-16 21:09:43Z roland $
  33  */
  34
  35 #include <linux/errno.h>
  36 #include <linux/spinlock.h>
  37 #include <linux/slab.h>
  38 #include <linux/jhash.h>
  39 #include <linux/kthread.h>
  40
  41 #include <ib_fmr_pool.h>
  42
  43 #include "core_priv.h"
  44
  45 enum {
  46         IB_FMR_MAX_REMAPS = 32,
  47
  48         IB_FMR_HASH_BITS  = 8,
  49         IB_FMR_HASH_SIZE  = 1 << IB_FMR_HASH_BITS,
  50         IB_FMR_HASH_MASK  = IB_FMR_HASH_SIZE - 1
  51 };
  52
  53 /*
  54  * If an FMR is not in use, then the list member will point to either
  55  * its pool's free_list (if the FMR can be mapped again; that is,
  56  * remap_count < IB_FMR_MAX_REMAPS) or its pool's dirty_list (if the
  57  * FMR needs to be unmapped before being remapped).  In either of
  58  * these cases it is a bug if the ref_count is not 0.  In other words,
  59  * if ref_count is > 0, then the list member must not be linked into
  60  * either free_list or dirty_list.
  61  *
  62  * The cache_node member is used to link the FMR into a cache bucket
  63  * (if caching is enabled).  This is independent of the reference
  64  * count of the FMR.  When a valid FMR is released, its ref_count is
  65  * decremented, and if ref_count reaches 0, the FMR is placed in
  66  * either free_list or dirty_list as appropriate.  However, it is not
  67  * removed from the cache and may be "revived" if a call to
  68  * ib_fmr_register_physical() occurs before the FMR is remapped.  In
  69  * this case we just increment the ref_count and remove the FMR from
  70  * free_list/dirty_list.
  71  *
  72  * Before we remap an FMR from free_list, we remove it from the cache
  73  * (to prevent another user from obtaining a stale FMR).  When an FMR
  74  * is released, we add it to the tail of the free list, so that our
  75  * cache eviction policy is "least recently used."
  76  *
  77  * All manipulation of ref_count, list and cache_node is protected by
  78  * pool_lock to maintain consistency.
  79  */
  80
  81 struct ib_fmr_pool {
  82         spinlock_t                pool_lock;
  83
  84         int                       pool_size;
  85         int                       max_pages;
  86         int                       dirty_watermark;
  87         int                       dirty_len;
  88         struct list_head          free_list;
  89         struct list_head          dirty_list;
  90         struct hlist_head        *cache_bucket;
  91
  92         void                     (*flush_function)(struct ib_fmr_pool *pool,
  93                                                    void *              arg);
  94         void                     *flush_arg;
  95
  96         struct task_struct       *thread;
  97
  98         atomic_t                  req_ser;
  99         atomic_t                  flush_ser;
 100
 101         wait_queue_head_t         force_wait;
 102 };
 103
 104 static inline u32 ib_fmr_hash(u64 first_page)
 105 {
 106         return jhash_2words((u32) first_page,
 107                             (u32) (first_page >> 32),
 108                             0);
 109 }
 110
 111 /* Caller must hold pool_lock */
 112 static inline struct ib_pool_fmr *ib_fmr_cache_lookup(struct ib_fmr_pool *pool,
 113                                                       u64 *page_list,
 114                                                       int  page_list_len,
 115                                                       u64  io_virtual_address)
 116 {
 117         struct hlist_head *bucket;
 118         struct ib_pool_fmr *fmr;
 119         struct hlist_node *pos;
 120
 121         if (!pool->cache_bucket)
 122                 return NULL;
 123
 124         bucket = pool->cache_bucket + ib_fmr_hash(*page_list);
 125
 126         hlist_for_each_entry(fmr, pos, bucket, cache_node)
 127                 if (io_virtual_address == fmr->io_virtual_address &&
 128                     page_list_len      == fmr->page_list_len      &&
 129                     !memcmp(page_list, fmr->page_list,
 130                             page_list_len * sizeof *page_list))
 131                         return fmr;
 132
 133         return NULL;
 134 }
 135
 136 static void ib_fmr_batch_release(struct ib_fmr_pool *pool)
 137 {
 138         int                 ret;
 139         struct ib_pool_fmr *fmr;
 140         LIST_HEAD(unmap_list);
 141         LIST_HEAD(fmr_list);
 142
 143         spin_lock_irq(&pool->pool_lock);
 144
 145         list_for_each_entry(fmr, &pool->dirty_list, list) {
 146                 hlist_del_init(&fmr->cache_node);
 147                 fmr->remap_count = 0;
 148                 list_add_tail(&fmr->fmr->list, &fmr_list);
 149
 150 #ifdef DEBUG
 151                 if (fmr->ref_count !=0) {
 152                         printk(KERN_WARNING "Unmapping FMR 0x%08x with ref count %d",
 153                                fmr, fmr->ref_count);
 154                 }
 155 #endif
 156         }
 157
 158         list_splice(&pool->dirty_list, &unmap_list);
 159         INIT_LIST_HEAD(&pool->dirty_list);
 160         pool->dirty_len = 0;
 161
 162         spin_unlock_irq(&pool->pool_lock);
 163
 164         if (list_empty(&unmap_list)) {
 165                 return;
 166         }
 167
 168         ret = ib_unmap_fmr(&fmr_list);
 169         if (ret)
 170                 printk(KERN_WARNING "ib_unmap_fmr returned %d", ret);
 171
 172         spin_lock_irq(&pool->pool_lock);
 173         list_splice(&unmap_list, &pool->free_list);
 174         spin_unlock_irq(&pool->pool_lock);
 175 }
 176
 177 static int ib_fmr_cleanup_thread(void *pool_ptr)
 178 {
 179         struct ib_fmr_pool *pool = pool_ptr;
 180
 181         do {
 182                 if (pool->dirty_len >= pool->dirty_watermark ||
 183                     atomic_read(&pool->flush_ser) - atomic_read(&pool->req_ser) < 0) {
 184                         ib_fmr_batch_release(pool);
 185
 186                         atomic_inc(&pool->flush_ser);
 187                         wake_up_interruptible(&pool->force_wait);
 188
 189                         if (pool->flush_function)
 190                                 pool->flush_function(pool, pool->flush_arg);
 191                 }
 192
 193                 set_current_state(TASK_INTERRUPTIBLE);
 194                 if (pool->dirty_len < pool->dirty_watermark &&
 195                     atomic_read(&pool->flush_ser) - atomic_read(&pool->req_ser) >= 0 &&
 196                     !kthread_should_stop())
 197                         schedule();
 198                 __set_current_state(TASK_RUNNING);
 199         } while (!kthread_should_stop());
 200
 201         return 0;
 202 }
 203
 204 /**
 205  * ib_create_fmr_pool - Create an FMR pool
 206  * @pd:Protection domain for FMRs
 207  * @params:FMR pool parameters
 208  *
 209  * Create a pool of FMRs.  Return value is pointer to new pool or
 210  * error code if creation failed.
 211  */
 212 struct ib_fmr_pool *ib_create_fmr_pool(struct ib_pd             *pd,
 213                                        struct ib_fmr_pool_param *params)
 214 {
 215         struct ib_device   *device;
 216         struct ib_fmr_pool *pool;
 217         int i;
 218         int ret;
 219
 220         if (!params)
 221                 return ERR_PTR(-EINVAL);
 222
 223         device = pd->device;
 224         if (!device->alloc_fmr    || !device->dealloc_fmr  ||
 225             !device->map_phys_fmr || !device->unmap_fmr) {
 226                 printk(KERN_WARNING "Device %s does not support fast memory regions",
 227                        device->name);
 228                 return ERR_PTR(-ENOSYS);
 229         }
 230
 231         pool = kmalloc(sizeof *pool, GFP_KERNEL);
 232         if (!pool) {
 233                 printk(KERN_WARNING "couldn't allocate pool struct");
 234                 return ERR_PTR(-ENOMEM);
 235         }
 236
 237         pool->cache_bucket   = NULL;
 238
 239         pool->flush_function = params->flush_function;
 240         pool->flush_arg      = params->flush_arg;
 241
 242         INIT_LIST_HEAD(&pool->free_list);
 243         INIT_LIST_HEAD(&pool->dirty_list);
 244
 245         if (params->cache) {
 246                 pool->cache_bucket =
 247                         kmalloc(IB_FMR_HASH_SIZE * sizeof *pool->cache_bucket,
 248                                 GFP_KERNEL);
 249                 if (!pool->cache_bucket) {
 250                         printk(KERN_WARNING "Failed to allocate cache in pool");
 251                         ret = -ENOMEM;
 252                         goto out_free_pool;
 253                 }
 254
 255                 for (i = 0; i < IB_FMR_HASH_SIZE; ++i)
 256                         INIT_HLIST_HEAD(pool->cache_bucket + i);
 257         }
 258
 259         pool->pool_size       = 0;
 260         pool->max_pages       = params->max_pages_per_fmr;
 261         pool->dirty_watermark = params->dirty_watermark;
 262         pool->dirty_len       = 0;
 263         spin_lock_init(&pool->pool_lock);
 264         atomic_set(&pool->req_ser,   0);
 265         atomic_set(&pool->flush_ser, 0);
 266         init_waitqueue_head(&pool->force_wait);
 267
 268         pool->thread = kthread_create(ib_fmr_cleanup_thread,
 269                                       pool,
 270                                       "ib_fmr(%s)",
 271                                       device->name);
 272         if (IS_ERR(pool->thread)) {
 273                 printk(KERN_WARNING "couldn't start cleanup thread");
 274                 ret = PTR_ERR(pool->thread);
 275                 goto out_free_pool;
 276         }
 277
 278         {
 279                 struct ib_pool_fmr *fmr;
 280                 struct ib_fmr_attr attr = {
 281                         .max_pages = params->max_pages_per_fmr,
 282                         .max_maps  = IB_FMR_MAX_REMAPS,
 283                         .page_size = PAGE_SHIFT
 284                 };
 285
 286                 for (i = 0; i < params->pool_size; ++i) {
 287                         fmr = kmalloc(sizeof *fmr + params->max_pages_per_fmr * sizeof (u64),
 288                                       GFP_KERNEL);
 289                         if (!fmr) {
 290                                 printk(KERN_WARNING "failed to allocate fmr struct "
 291                                        "for FMR %d", i);
 292                                 goto out_fail;
 293                         }
 294
 295                         fmr->pool             = pool;
 296                         fmr->remap_count      = 0;
 297                         fmr->ref_count        = 0;
 298                         INIT_HLIST_NODE(&fmr->cache_node);
 299
 300                         fmr->fmr = ib_alloc_fmr(pd, params->access, &attr);
 301                         if (IS_ERR(fmr->fmr)) {
 302                                 printk(KERN_WARNING "fmr_create failed for FMR %d", i);
 303                                 kfree(fmr);
 304                                 goto out_fail;
 305                         }
 306
 307                         list_add_tail(&fmr->list, &pool->free_list);
 308                         ++pool->pool_size;
 309                 }
 310         }
 311
 312         return pool;
 313
 314  out_free_pool:
 315         kfree(pool->cache_bucket);
 316         kfree(pool);
 317
 318         return ERR_PTR(ret);
 319
 320  out_fail:
 321         ib_destroy_fmr_pool(pool);
 322
 323         return ERR_PTR(-ENOMEM);
 324 }
 325 EXPORT_SYMBOL(ib_create_fmr_pool);
 326
 327 /**
 328  * ib_destroy_fmr_pool - Free FMR pool
 329  * @pool:FMR pool to free
 330  *
 331  * Destroy an FMR pool and free all associated resources.
 332  */
 333 int ib_destroy_fmr_pool(struct ib_fmr_pool *pool)
 334 {
 335         struct ib_pool_fmr *fmr;
 336         struct ib_pool_fmr *tmp;
 337         int                 i;
 338
 339         kthread_stop(pool->thread);
 340         ib_fmr_batch_release(pool);
 341
 342         i = 0;
 343         list_for_each_entry_safe(fmr, tmp, &pool->free_list, list) {
 344                 ib_dealloc_fmr(fmr->fmr);
 345                 list_del(&fmr->list);
 346                 kfree(fmr);
 347                 ++i;
 348         }
 349
 350         if (i < pool->pool_size)
 351                 printk(KERN_WARNING "pool still has %d regions registered",
 352                        pool->pool_size - i);
 353
 354         kfree(pool->cache_bucket);
 355         kfree(pool);
 356
 357         return 0;
 358 }
 359 EXPORT_SYMBOL(ib_destroy_fmr_pool);
 360
 361 /**
 362  * ib_flush_fmr_pool - Invalidate all unmapped FMRs
 363  * @pool:FMR pool to flush
 364  *
 365  * Ensure that all unmapped FMRs are fully invalidated.
 366  */
 367 int ib_flush_fmr_pool(struct ib_fmr_pool *pool)
 368 {
 369         int serial;
 370
 371         atomic_inc(&pool->req_ser);
 372         /*
 373          * It's OK if someone else bumps req_ser again here -- we'll
 374          * just wait a little longer.
 375          */
 376         serial = atomic_read(&pool->req_ser);
 377
 378         wake_up_process(pool->thread);
 379
 380         if (wait_event_interruptible(pool->force_wait,
 381                                      atomic_read(&pool->flush_ser) -
 382                                      atomic_read(&pool->req_ser) >= 0))
 383                 return -EINTR;
 384
 385         return 0;
 386 }
 387 EXPORT_SYMBOL(ib_flush_fmr_pool);
 388
 389 /**
 390  * ib_fmr_pool_map_phys -
 391  * @pool:FMR pool to allocate FMR from
 392  * @page_list:List of pages to map
 393  * @list_len:Number of pages in @page_list
 394  * @io_virtual_address:I/O virtual address for new FMR
 395  *
 396  * Map an FMR from an FMR pool.
 397  */
 398 struct ib_pool_fmr *ib_fmr_pool_map_phys(struct ib_fmr_pool *pool_handle,
 399                                          u64                *page_list,
 400                                          int                 list_len,
 401                                          u64                *io_virtual_address)
 402 {
 403         struct ib_fmr_pool *pool = pool_handle;
 404         struct ib_pool_fmr *fmr;
 405         unsigned long       flags;
 406         int                 result;
 407
 408         if (list_len < 1 || list_len > pool->max_pages)
 409                 return ERR_PTR(-EINVAL);
 410
 411         spin_lock_irqsave(&pool->pool_lock, flags);
 412         fmr = ib_fmr_cache_lookup(pool,
 413                                   page_list,
 414                                   list_len,
 415                                   *io_virtual_address);
 416         if (fmr) {
 417                 /* found in cache */
 418                 ++fmr->ref_count;
 419                 if (fmr->ref_count == 1) {
 420                         list_del(&fmr->list);
 421                 }
 422
 423                 spin_unlock_irqrestore(&pool->pool_lock, flags);
 424
 425                 return fmr;
 426         }
 427
 428         if (list_empty(&pool->free_list)) {
 429                 spin_unlock_irqrestore(&pool->pool_lock, flags);
 430                 return ERR_PTR(-EAGAIN);
 431         }
 432
 433         fmr = list_entry(pool->free_list.next, struct ib_pool_fmr, list);
 434         list_del(&fmr->list);
 435         hlist_del_init(&fmr->cache_node);
 436         spin_unlock_irqrestore(&pool->pool_lock, flags);
 437
 438         result = ib_map_phys_fmr(fmr->fmr, page_list, list_len,
 439                                  *io_virtual_address);
 440
 441         if (result) {
 442                 spin_lock_irqsave(&pool->pool_lock, flags);
 443                 list_add(&fmr->list, &pool->free_list);
 444                 spin_unlock_irqrestore(&pool->pool_lock, flags);
 445
 446                 printk(KERN_WARNING "fmr_map returns %d",
 447                        result);
 448
 449                 return ERR_PTR(result);
 450         }
 451
 452         ++fmr->remap_count;
 453         fmr->ref_count = 1;
 454
 455         if (pool->cache_bucket) {
 456                 fmr->io_virtual_address = *io_virtual_address;
 457                 fmr->page_list_len      = list_len;
 458                 memcpy(fmr->page_list, page_list, list_len * sizeof(*page_list));
 459
 460                 spin_lock_irqsave(&pool->pool_lock, flags);
 461                 hlist_add_head(&fmr->cache_node,
 462                                pool->cache_bucket + ib_fmr_hash(fmr->page_list[0]));
 463                 spin_unlock_irqrestore(&pool->pool_lock, flags);
 464         }
 465
 466         return fmr;
 467 }
 468 EXPORT_SYMBOL(ib_fmr_pool_map_phys);
 469
 470 /**
 471  * ib_fmr_pool_unmap - Unmap FMR
 472  * @fmr:FMR to unmap
 473  *
 474  * Unmap an FMR.  The FMR mapping may remain valid until the FMR is
 475  * reused (or until ib_flush_fmr_pool() is called).
 476  */
 477 int ib_fmr_pool_unmap(struct ib_pool_fmr *fmr)
 478 {
 479         struct ib_fmr_pool *pool;
 480         unsigned long flags;
 481
 482         pool = fmr->pool;
 483
 484         spin_lock_irqsave(&pool->pool_lock, flags);
 485
 486         --fmr->ref_count;
 487         if (!fmr->ref_count) {
 488                 if (fmr->remap_count < IB_FMR_MAX_REMAPS) {
 489                         list_add_tail(&fmr->list, &pool->free_list);
 490                 } else {
 491                         list_add_tail(&fmr->list, &pool->dirty_list);
 492                         ++pool->dirty_len;
 493                         wake_up_process(pool->thread);
 494                 }
 495         }
 496
 497 #ifdef DEBUG
 498         if (fmr->ref_count < 0)
 499                 printk(KERN_WARNING "FMR %p has ref count %d < 0",
 500                        fmr, fmr->ref_count);
 501 #endif
 502
 503         spin_unlock_irqrestore(&pool->pool_lock, flags);
 504
 505         return 0;
 506 }
 507 EXPORT_SYMBOL(ib_fmr_pool_unmap);