drivers/infiniband/core/fmr_pool.c

   1 /*
   2  * Copyright (c) 2004 Topspin Communications.  All rights reserved.
   3  * Copyright (c) 2005 Sun Microsystems, Inc. All rights reserved.
   4  *
   5  * This software is available to you under a choice of one of two
   6  * licenses.  You may choose to be licensed under the terms of the GNU
   7  * General Public License (GPL) Version 2, available from the file
   8  * COPYING in the main directory of this source tree, or the
   9  * OpenIB.org BSD license below:
  10  *
  11  *     Redistribution and use in source and binary forms, with or
  12  *     without modification, are permitted provided that the following
  13  *     conditions are met:
  14  *
  15  *      - Redistributions of source code must retain the above
  16  *        copyright notice, this list of conditions and the following
  17  *        disclaimer.
  18  *
  19  *      - Redistributions in binary form must reproduce the above
  20  *        copyright notice, this list of conditions and the following
  21  *        disclaimer in the documentation and/or other materials
  22  *        provided with the distribution.
  23  *
  24  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  25  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  26  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  27  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  28  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  29  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  30  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  31  * SOFTWARE.
  32  *
  33  * $Id: fmr_pool.c 2730 2005-06-28 16:43:03Z sean.hefty $
  34  */
  35
  36 #include <linux/errno.h>
  37 #include <linux/spinlock.h>
  38 #include <linux/slab.h>
  39 #include <linux/jhash.h>
  40 #include <linux/kthread.h>
  41
  42 #include <rdma/ib_fmr_pool.h>
  43
  44 #include "core_priv.h"
  45
  46 #define PFX "fmr_pool: "
  47
  48 enum {
  49         IB_FMR_MAX_REMAPS = 32,
  50
  51         IB_FMR_HASH_BITS  = 8,
  52         IB_FMR_HASH_SIZE  = 1 << IB_FMR_HASH_BITS,
  53         IB_FMR_HASH_MASK  = IB_FMR_HASH_SIZE - 1
  54 };
  55
  56 /*
  57  * If an FMR is not in use, then the list member will point to either
  58  * its pool's free_list (if the FMR can be mapped again; that is,
  59  * remap_count < pool->max_remaps) or its pool's dirty_list (if the
  60  * FMR needs to be unmapped before being remapped).  In either of
  61  * these cases it is a bug if the ref_count is not 0.  In other words,
  62  * if ref_count is > 0, then the list member must not be linked into
  63  * either free_list or dirty_list.
  64  *
  65  * The cache_node member is used to link the FMR into a cache bucket
  66  * (if caching is enabled).  This is independent of the reference
  67  * count of the FMR.  When a valid FMR is released, its ref_count is
  68  * decremented, and if ref_count reaches 0, the FMR is placed in
  69  * either free_list or dirty_list as appropriate.  However, it is not
  70  * removed from the cache and may be "revived" if a call to
  71  * ib_fmr_register_physical() occurs before the FMR is remapped.  In
  72  * this case we just increment the ref_count and remove the FMR from
  73  * free_list/dirty_list.
  74  *
  75  * Before we remap an FMR from free_list, we remove it from the cache
  76  * (to prevent another user from obtaining a stale FMR).  When an FMR
  77  * is released, we add it to the tail of the free list, so that our
  78  * cache eviction policy is "least recently used."
  79  *
  80  * All manipulation of ref_count, list and cache_node is protected by
  81  * pool_lock to maintain consistency.
  82  */
  83
  84 struct ib_fmr_pool {
  85         spinlock_t                pool_lock;
  86
  87         int                       pool_size;
  88         int                       max_pages;
  89         int                       max_remaps;
  90         int                       dirty_watermark;
  91         int                       dirty_len;
  92         struct list_head          free_list;
  93         struct list_head          dirty_list;
  94         struct hlist_head        *cache_bucket;
  95
  96         void                     (*flush_function)(struct ib_fmr_pool *pool,
  97                                                    void *              arg);
  98         void                     *flush_arg;
  99
 100         struct task_struct       *thread;
 101
 102         atomic_t                  req_ser;
 103         atomic_t                  flush_ser;
 104
 105         wait_queue_head_t         force_wait;
 106 };
 107
 108 static inline u32 ib_fmr_hash(u64 first_page)
 109 {
 110         return jhash_2words((u32) first_page, (u32) (first_page >> 32), 0) &
 111                 (IB_FMR_HASH_SIZE - 1);
 112 }
 113
 114 /* Caller must hold pool_lock */
 115 static inline struct ib_pool_fmr *ib_fmr_cache_lookup(struct ib_fmr_pool *pool,
 116                                                       u64 *page_list,
 117                                                       int  page_list_len,
 118                                                       u64  io_virtual_address)
 119 {
 120         struct hlist_head *bucket;
 121         struct ib_pool_fmr *fmr;
 122         struct hlist_node *pos;
 123
 124         if (!pool->cache_bucket)
 125                 return NULL;
 126
 127         bucket = pool->cache_bucket + ib_fmr_hash(*page_list);
 128
 129         hlist_for_each_entry(fmr, pos, bucket, cache_node)
 130                 if (io_virtual_address == fmr->io_virtual_address &&
 131                     page_list_len      == fmr->page_list_len      &&
 132                     !memcmp(page_list, fmr->page_list,
 133                             page_list_len * sizeof *page_list))
 134                         return fmr;
 135
 136         return NULL;
 137 }
 138
 139 static void ib_fmr_batch_release(struct ib_fmr_pool *pool)
 140 {
 141         int                 ret;
 142         struct ib_pool_fmr *fmr;
 143         LIST_HEAD(unmap_list);
 144         LIST_HEAD(fmr_list);
 145
 146         spin_lock_irq(&pool->pool_lock);
 147
 148         list_for_each_entry(fmr, &pool->dirty_list, list) {
 149                 hlist_del_init(&fmr->cache_node);
 150                 fmr->remap_count = 0;
 151                 list_add_tail(&fmr->fmr->list, &fmr_list);
 152
 153 #ifdef DEBUG
 154                 if (fmr->ref_count !=0) {
 155                         printk(KERN_WARNING PFX "Unmapping FMR 0x%08x with ref count %d\n",
 156                                fmr, fmr->ref_count);
 157                 }
 158 #endif
 159         }
 160
 161         list_splice(&pool->dirty_list, &unmap_list);
 162         INIT_LIST_HEAD(&pool->dirty_list);
 163         pool->dirty_len = 0;
 164
 165         spin_unlock_irq(&pool->pool_lock);
 166
 167         if (list_empty(&unmap_list)) {
 168                 return;
 169         }
 170
 171         ret = ib_unmap_fmr(&fmr_list);
 172         if (ret)
 173                 printk(KERN_WARNING PFX "ib_unmap_fmr returned %d\n", ret);
 174
 175         spin_lock_irq(&pool->pool_lock);
 176         list_splice(&unmap_list, &pool->free_list);
 177         spin_unlock_irq(&pool->pool_lock);
 178 }
 179
 180 static int ib_fmr_cleanup_thread(void *pool_ptr)
 181 {
 182         struct ib_fmr_pool *pool = pool_ptr;
 183
 184         do {
 185                 if (atomic_read(&pool->flush_ser) - atomic_read(&pool->req_ser) < 0) {
 186                         ib_fmr_batch_release(pool);
 187
 188                         atomic_inc(&pool->flush_ser);
 189                         wake_up_interruptible(&pool->force_wait);
 190
 191                         if (pool->flush_function)
 192                                 pool->flush_function(pool, pool->flush_arg);
 193                 }
 194
 195                 set_current_state(TASK_INTERRUPTIBLE);
 196                 if (atomic_read(&pool->flush_ser) - atomic_read(&pool->req_ser) >= 0 &&
 197                     !kthread_should_stop())
 198                         schedule();
 199                 __set_current_state(TASK_RUNNING);
 200         } while (!kthread_should_stop());
 201
 202         return 0;
 203 }
 204
 205 /**
 206  * ib_create_fmr_pool - Create an FMR pool
 207  * @pd:Protection domain for FMRs
 208  * @params:FMR pool parameters
 209  *
 210  * Create a pool of FMRs.  Return value is pointer to new pool or
 211  * error code if creation failed.
 212  */
 213 struct ib_fmr_pool *ib_create_fmr_pool(struct ib_pd             *pd,
 214                                        struct ib_fmr_pool_param *params)
 215 {
 216         struct ib_device   *device;
 217         struct ib_fmr_pool *pool;
 218         struct ib_device_attr *attr;
 219         int i;
 220         int ret;
 221         int max_remaps;
 222
 223         if (!params)
 224                 return ERR_PTR(-EINVAL);
 225
 226         device = pd->device;
 227         if (!device->alloc_fmr    || !device->dealloc_fmr  ||
 228             !device->map_phys_fmr || !device->unmap_fmr) {
 229                 printk(KERN_INFO PFX "Device %s does not support FMRs\n",
 230                        device->name);
 231                 return ERR_PTR(-ENOSYS);
 232         }
 233
 234         attr = kmalloc(sizeof *attr, GFP_KERNEL);
 235         if (!attr) {
 236                 printk(KERN_WARNING PFX "couldn't allocate device attr struct\n");
 237                 return ERR_PTR(-ENOMEM);
 238         }
 239
 240         ret = ib_query_device(device, attr);
 241         if (ret) {
 242                 printk(KERN_WARNING PFX "couldn't query device: %d\n", ret);
 243                 kfree(attr);
 244                 return ERR_PTR(ret);
 245         }
 246
 247         if (!attr->max_map_per_fmr)
 248                 max_remaps = IB_FMR_MAX_REMAPS;
 249         else
 250                 max_remaps = attr->max_map_per_fmr;
 251
 252         kfree(attr);
 253
 254         pool = kmalloc(sizeof *pool, GFP_KERNEL);
 255         if (!pool) {
 256                 printk(KERN_WARNING PFX "couldn't allocate pool struct\n");
 257                 return ERR_PTR(-ENOMEM);
 258         }
 259
 260         pool->cache_bucket   = NULL;
 261
 262         pool->flush_function = params->flush_function;
 263         pool->flush_arg      = params->flush_arg;
 264
 265         INIT_LIST_HEAD(&pool->free_list);
 266         INIT_LIST_HEAD(&pool->dirty_list);
 267
 268         if (params->cache) {
 269                 pool->cache_bucket =
 270                         kmalloc(IB_FMR_HASH_SIZE * sizeof *pool->cache_bucket,
 271                                 GFP_KERNEL);
 272                 if (!pool->cache_bucket) {
 273                         printk(KERN_WARNING PFX "Failed to allocate cache in pool\n");
 274                         ret = -ENOMEM;
 275                         goto out_free_pool;
 276                 }
 277
 278                 for (i = 0; i < IB_FMR_HASH_SIZE; ++i)
 279                         INIT_HLIST_HEAD(pool->cache_bucket + i);
 280         }
 281
 282         pool->pool_size       = 0;
 283         pool->max_pages       = params->max_pages_per_fmr;
 284         pool->max_remaps      = max_remaps;
 285         pool->dirty_watermark = params->dirty_watermark;
 286         pool->dirty_len       = 0;
 287         spin_lock_init(&pool->pool_lock);
 288         atomic_set(&pool->req_ser,   0);
 289         atomic_set(&pool->flush_ser, 0);
 290         init_waitqueue_head(&pool->force_wait);
 291
 292         pool->thread = kthread_run(ib_fmr_cleanup_thread,
 293                                    pool,
 294                                    "ib_fmr(%s)",
 295                                    device->name);
 296         if (IS_ERR(pool->thread)) {
 297                 printk(KERN_WARNING PFX "couldn't start cleanup thread\n");
 298                 ret = PTR_ERR(pool->thread);
 299                 goto out_free_pool;
 300         }
 301
 302         {
 303                 struct ib_pool_fmr *fmr;
 304                 struct ib_fmr_attr fmr_attr = {
 305                         .max_pages  = params->max_pages_per_fmr,
 306                         .max_maps   = pool->max_remaps,
 307                         .page_shift = params->page_shift
 308                 };
 309                 int bytes_per_fmr = sizeof *fmr;
 310
 311                 if (pool->cache_bucket)
 312                         bytes_per_fmr += params->max_pages_per_fmr * sizeof (u64);
 313
 314                 for (i = 0; i < params->pool_size; ++i) {
 315                         fmr = kmalloc(bytes_per_fmr, GFP_KERNEL);
 316                         if (!fmr) {
 317                                 printk(KERN_WARNING PFX "failed to allocate fmr "
 318                                        "struct for FMR %d\n", i);
 319                                 goto out_fail;
 320                         }
 321
 322                         fmr->pool             = pool;
 323                         fmr->remap_count      = 0;
 324                         fmr->ref_count        = 0;
 325                         INIT_HLIST_NODE(&fmr->cache_node);
 326
 327                         fmr->fmr = ib_alloc_fmr(pd, params->access, &fmr_attr);
 328                         if (IS_ERR(fmr->fmr)) {
 329                                 printk(KERN_WARNING PFX "fmr_create failed "
 330                                        "for FMR %d\n", i);
 331                                 kfree(fmr);
 332                                 goto out_fail;
 333                         }
 334
 335                         list_add_tail(&fmr->list, &pool->free_list);
 336                         ++pool->pool_size;
 337                 }
 338         }
 339
 340         return pool;
 341
 342  out_free_pool:
 343         kfree(pool->cache_bucket);
 344         kfree(pool);
 345
 346         return ERR_PTR(ret);
 347
 348  out_fail:
 349         ib_destroy_fmr_pool(pool);
 350
 351         return ERR_PTR(-ENOMEM);
 352 }
 353 EXPORT_SYMBOL(ib_create_fmr_pool);
 354
 355 /**
 356  * ib_destroy_fmr_pool - Free FMR pool
 357  * @pool:FMR pool to free
 358  *
 359  * Destroy an FMR pool and free all associated resources.
 360  */
 361 void ib_destroy_fmr_pool(struct ib_fmr_pool *pool)
 362 {
 363         struct ib_pool_fmr *fmr;
 364         struct ib_pool_fmr *tmp;
 365         LIST_HEAD(fmr_list);
 366         int                 i;
 367
 368         kthread_stop(pool->thread);
 369         ib_fmr_batch_release(pool);
 370
 371         i = 0;
 372         list_for_each_entry_safe(fmr, tmp, &pool->free_list, list) {
 373                 if (fmr->remap_count) {
 374                         INIT_LIST_HEAD(&fmr_list);
 375                         list_add_tail(&fmr->fmr->list, &fmr_list);
 376                         ib_unmap_fmr(&fmr_list);
 377                 }
 378                 ib_dealloc_fmr(fmr->fmr);
 379                 list_del(&fmr->list);
 380                 kfree(fmr);
 381                 ++i;
 382         }
 383
 384         if (i < pool->pool_size)
 385                 printk(KERN_WARNING PFX "pool still has %d regions registered\n",
 386                        pool->pool_size - i);
 387
 388         kfree(pool->cache_bucket);
 389         kfree(pool);
 390 }
 391 EXPORT_SYMBOL(ib_destroy_fmr_pool);
 392
 393 /**
 394  * ib_flush_fmr_pool - Invalidate all unmapped FMRs
 395  * @pool:FMR pool to flush
 396  *
 397  * Ensure that all unmapped FMRs are fully invalidated.
 398  */
 399 int ib_flush_fmr_pool(struct ib_fmr_pool *pool)
 400 {
 401         int serial;
 402         struct ib_pool_fmr *fmr, *next;
 403
 404         /*
 405          * The free_list holds FMRs that may have been used
 406          * but have not been remapped enough times to be dirty.
 407          * Put them on the dirty list now so that the cleanup
 408          * thread will reap them too.
 409          */
 410         spin_lock_irq(&pool->pool_lock);
 411         list_for_each_entry_safe(fmr, next, &pool->free_list, list) {
 412                 if (fmr->remap_count > 0)
 413                         list_move(&fmr->list, &pool->dirty_list);
 414         }
 415         spin_unlock_irq(&pool->pool_lock);
 416
 417         serial = atomic_inc_return(&pool->req_ser);
 418         wake_up_process(pool->thread);
 419
 420         if (wait_event_interruptible(pool->force_wait,
 421                                      atomic_read(&pool->flush_ser) - serial >= 0))
 422                 return -EINTR;
 423
 424         return 0;
 425 }
 426 EXPORT_SYMBOL(ib_flush_fmr_pool);
 427
 428 /**
 429  * ib_fmr_pool_map_phys -
 430  * @pool:FMR pool to allocate FMR from
 431  * @page_list:List of pages to map
 432  * @list_len:Number of pages in @page_list
 433  * @io_virtual_address:I/O virtual address for new FMR
 434  *
 435  * Map an FMR from an FMR pool.
 436  */
 437 struct ib_pool_fmr *ib_fmr_pool_map_phys(struct ib_fmr_pool *pool_handle,
 438                                          u64                *page_list,
 439                                          int                 list_len,
 440                                          u64                 io_virtual_address)
 441 {
 442         struct ib_fmr_pool *pool = pool_handle;
 443         struct ib_pool_fmr *fmr;
 444         unsigned long       flags;
 445         int                 result;
 446
 447         if (list_len < 1 || list_len > pool->max_pages)
 448                 return ERR_PTR(-EINVAL);
 449
 450         spin_lock_irqsave(&pool->pool_lock, flags);
 451         fmr = ib_fmr_cache_lookup(pool,
 452                                   page_list,
 453                                   list_len,
 454                                   io_virtual_address);
 455         if (fmr) {
 456                 /* found in cache */
 457                 ++fmr->ref_count;
 458                 if (fmr->ref_count == 1) {
 459                         list_del(&fmr->list);
 460                 }
 461
 462                 spin_unlock_irqrestore(&pool->pool_lock, flags);
 463
 464                 return fmr;
 465         }
 466
 467         if (list_empty(&pool->free_list)) {
 468                 spin_unlock_irqrestore(&pool->pool_lock, flags);
 469                 return ERR_PTR(-EAGAIN);
 470         }
 471
 472         fmr = list_entry(pool->free_list.next, struct ib_pool_fmr, list);
 473         list_del(&fmr->list);
 474         hlist_del_init(&fmr->cache_node);
 475         spin_unlock_irqrestore(&pool->pool_lock, flags);
 476
 477         result = ib_map_phys_fmr(fmr->fmr, page_list, list_len,
 478                                  io_virtual_address);
 479
 480         if (result) {
 481                 spin_lock_irqsave(&pool->pool_lock, flags);
 482                 list_add(&fmr->list, &pool->free_list);
 483                 spin_unlock_irqrestore(&pool->pool_lock, flags);
 484
 485                 printk(KERN_WARNING PFX "fmr_map returns %d\n", result);
 486
 487                 return ERR_PTR(result);
 488         }
 489
 490         ++fmr->remap_count;
 491         fmr->ref_count = 1;
 492
 493         if (pool->cache_bucket) {
 494                 fmr->io_virtual_address = io_virtual_address;
 495                 fmr->page_list_len      = list_len;
 496                 memcpy(fmr->page_list, page_list, list_len * sizeof(*page_list));
 497
 498                 spin_lock_irqsave(&pool->pool_lock, flags);
 499                 hlist_add_head(&fmr->cache_node,
 500                                pool->cache_bucket + ib_fmr_hash(fmr->page_list[0]));
 501                 spin_unlock_irqrestore(&pool->pool_lock, flags);
 502         }
 503
 504         return fmr;
 505 }
 506 EXPORT_SYMBOL(ib_fmr_pool_map_phys);
 507
 508 /**
 509  * ib_fmr_pool_unmap - Unmap FMR
 510  * @fmr:FMR to unmap
 511  *
 512  * Unmap an FMR.  The FMR mapping may remain valid until the FMR is
 513  * reused (or until ib_flush_fmr_pool() is called).
 514  */
 515 int ib_fmr_pool_unmap(struct ib_pool_fmr *fmr)
 516 {
 517         struct ib_fmr_pool *pool;
 518         unsigned long flags;
 519
 520         pool = fmr->pool;
 521
 522         spin_lock_irqsave(&pool->pool_lock, flags);
 523
 524         --fmr->ref_count;
 525         if (!fmr->ref_count) {
 526                 if (fmr->remap_count < pool->max_remaps) {
 527                         list_add_tail(&fmr->list, &pool->free_list);
 528                 } else {
 529                         list_add_tail(&fmr->list, &pool->dirty_list);
 530                         if (++pool->dirty_len >= pool->dirty_watermark) {
 531                                 atomic_inc(&pool->req_ser);
 532                                 wake_up_process(pool->thread);
 533                         }
 534                 }
 535         }
 536
 537 #ifdef DEBUG
 538         if (fmr->ref_count < 0)
 539                 printk(KERN_WARNING PFX "FMR %p has ref count %d < 0\n",
 540                        fmr, fmr->ref_count);
 541 #endif
 542
 543         spin_unlock_irqrestore(&pool->pool_lock, flags);
 544
 545         return 0;
 546 }
 547 EXPORT_SYMBOL(ib_fmr_pool_unmap);