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, *next;
 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         /*
 162          * The free_list may hold FMRs that have been put there
 163          * because they haven't reached the max_remap count.
 164          * Invalidate their mapping as well.
 165          */
 166         list_for_each_entry_safe(fmr, next, &pool->free_list, list) {
 167                 if (fmr->remap_count == 0)
 168                         continue;
 169                 hlist_del_init(&fmr->cache_node);
 170                 fmr->remap_count = 0;
 171                 list_add_tail(&fmr->fmr->list, &fmr_list);
 172                 list_move(&fmr->list, &unmap_list);
 173         }
 174
 175         list_splice(&pool->dirty_list, &unmap_list);
 176         INIT_LIST_HEAD(&pool->dirty_list);
 177         pool->dirty_len = 0;
 178
 179         spin_unlock_irq(&pool->pool_lock);
 180
 181         if (list_empty(&unmap_list)) {
 182                 return;
 183         }
 184
 185         ret = ib_unmap_fmr(&fmr_list);
 186         if (ret)
 187                 printk(KERN_WARNING PFX "ib_unmap_fmr returned %d\n", ret);
 188
 189         spin_lock_irq(&pool->pool_lock);
 190         list_splice(&unmap_list, &pool->free_list);
 191         spin_unlock_irq(&pool->pool_lock);
 192 }
 193
 194 static int ib_fmr_cleanup_thread(void *pool_ptr)
 195 {
 196         struct ib_fmr_pool *pool = pool_ptr;
 197
 198         do {
 199                 if (atomic_read(&pool->flush_ser) - atomic_read(&pool->req_ser) < 0) {
 200                         ib_fmr_batch_release(pool);
 201
 202                         atomic_inc(&pool->flush_ser);
 203                         wake_up_interruptible(&pool->force_wait);
 204
 205                         if (pool->flush_function)
 206                                 pool->flush_function(pool, pool->flush_arg);
 207                 }
 208
 209                 set_current_state(TASK_INTERRUPTIBLE);
 210                 if (atomic_read(&pool->flush_ser) - atomic_read(&pool->req_ser) >= 0 &&
 211                     !kthread_should_stop())
 212                         schedule();
 213                 __set_current_state(TASK_RUNNING);
 214         } while (!kthread_should_stop());
 215
 216         return 0;
 217 }
 218
 219 /**
 220  * ib_create_fmr_pool - Create an FMR pool
 221  * @pd:Protection domain for FMRs
 222  * @params:FMR pool parameters
 223  *
 224  * Create a pool of FMRs.  Return value is pointer to new pool or
 225  * error code if creation failed.
 226  */
 227 struct ib_fmr_pool *ib_create_fmr_pool(struct ib_pd             *pd,
 228                                        struct ib_fmr_pool_param *params)
 229 {
 230         struct ib_device   *device;
 231         struct ib_fmr_pool *pool;
 232         struct ib_device_attr *attr;
 233         int i;
 234         int ret;
 235         int max_remaps;
 236
 237         if (!params)
 238                 return ERR_PTR(-EINVAL);
 239
 240         device = pd->device;
 241         if (!device->alloc_fmr    || !device->dealloc_fmr  ||
 242             !device->map_phys_fmr || !device->unmap_fmr) {
 243                 printk(KERN_INFO PFX "Device %s does not support FMRs\n",
 244                        device->name);
 245                 return ERR_PTR(-ENOSYS);
 246         }
 247
 248         attr = kmalloc(sizeof *attr, GFP_KERNEL);
 249         if (!attr) {
 250                 printk(KERN_WARNING PFX "couldn't allocate device attr struct\n");
 251                 return ERR_PTR(-ENOMEM);
 252         }
 253
 254         ret = ib_query_device(device, attr);
 255         if (ret) {
 256                 printk(KERN_WARNING PFX "couldn't query device: %d\n", ret);
 257                 kfree(attr);
 258                 return ERR_PTR(ret);
 259         }
 260
 261         if (!attr->max_map_per_fmr)
 262                 max_remaps = IB_FMR_MAX_REMAPS;
 263         else
 264                 max_remaps = attr->max_map_per_fmr;
 265
 266         kfree(attr);
 267
 268         pool = kmalloc(sizeof *pool, GFP_KERNEL);
 269         if (!pool) {
 270                 printk(KERN_WARNING PFX "couldn't allocate pool struct\n");
 271                 return ERR_PTR(-ENOMEM);
 272         }
 273
 274         pool->cache_bucket   = NULL;
 275
 276         pool->flush_function = params->flush_function;
 277         pool->flush_arg      = params->flush_arg;
 278
 279         INIT_LIST_HEAD(&pool->free_list);
 280         INIT_LIST_HEAD(&pool->dirty_list);
 281
 282         if (params->cache) {
 283                 pool->cache_bucket =
 284                         kmalloc(IB_FMR_HASH_SIZE * sizeof *pool->cache_bucket,
 285                                 GFP_KERNEL);
 286                 if (!pool->cache_bucket) {
 287                         printk(KERN_WARNING PFX "Failed to allocate cache in pool\n");
 288                         ret = -ENOMEM;
 289                         goto out_free_pool;
 290                 }
 291
 292                 for (i = 0; i < IB_FMR_HASH_SIZE; ++i)
 293                         INIT_HLIST_HEAD(pool->cache_bucket + i);
 294         }
 295
 296         pool->pool_size       = 0;
 297         pool->max_pages       = params->max_pages_per_fmr;
 298         pool->max_remaps      = max_remaps;
 299         pool->dirty_watermark = params->dirty_watermark;
 300         pool->dirty_len       = 0;
 301         spin_lock_init(&pool->pool_lock);
 302         atomic_set(&pool->req_ser,   0);
 303         atomic_set(&pool->flush_ser, 0);
 304         init_waitqueue_head(&pool->force_wait);
 305
 306         pool->thread = kthread_run(ib_fmr_cleanup_thread,
 307                                    pool,
 308                                    "ib_fmr(%s)",
 309                                    device->name);
 310         if (IS_ERR(pool->thread)) {
 311                 printk(KERN_WARNING PFX "couldn't start cleanup thread\n");
 312                 ret = PTR_ERR(pool->thread);
 313                 goto out_free_pool;
 314         }
 315
 316         {
 317                 struct ib_pool_fmr *fmr;
 318                 struct ib_fmr_attr fmr_attr = {
 319                         .max_pages  = params->max_pages_per_fmr,
 320                         .max_maps   = pool->max_remaps,
 321                         .page_shift = params->page_shift
 322                 };
 323                 int bytes_per_fmr = sizeof *fmr;
 324
 325                 if (pool->cache_bucket)
 326                         bytes_per_fmr += params->max_pages_per_fmr * sizeof (u64);
 327
 328                 for (i = 0; i < params->pool_size; ++i) {
 329                         fmr = kmalloc(bytes_per_fmr, GFP_KERNEL);
 330                         if (!fmr) {
 331                                 printk(KERN_WARNING PFX "failed to allocate fmr "
 332                                        "struct for FMR %d\n", i);
 333                                 goto out_fail;
 334                         }
 335
 336                         fmr->pool             = pool;
 337                         fmr->remap_count      = 0;
 338                         fmr->ref_count        = 0;
 339                         INIT_HLIST_NODE(&fmr->cache_node);
 340
 341                         fmr->fmr = ib_alloc_fmr(pd, params->access, &fmr_attr);
 342                         if (IS_ERR(fmr->fmr)) {
 343                                 printk(KERN_WARNING PFX "fmr_create failed "
 344                                        "for FMR %d\n", i);
 345                                 kfree(fmr);
 346                                 goto out_fail;
 347                         }
 348
 349                         list_add_tail(&fmr->list, &pool->free_list);
 350                         ++pool->pool_size;
 351                 }
 352         }
 353
 354         return pool;
 355
 356  out_free_pool:
 357         kfree(pool->cache_bucket);
 358         kfree(pool);
 359
 360         return ERR_PTR(ret);
 361
 362  out_fail:
 363         ib_destroy_fmr_pool(pool);
 364
 365         return ERR_PTR(-ENOMEM);
 366 }
 367 EXPORT_SYMBOL(ib_create_fmr_pool);
 368
 369 /**
 370  * ib_destroy_fmr_pool - Free FMR pool
 371  * @pool:FMR pool to free
 372  *
 373  * Destroy an FMR pool and free all associated resources.
 374  */
 375 void ib_destroy_fmr_pool(struct ib_fmr_pool *pool)
 376 {
 377         struct ib_pool_fmr *fmr;
 378         struct ib_pool_fmr *tmp;
 379         LIST_HEAD(fmr_list);
 380         int                 i;
 381
 382         kthread_stop(pool->thread);
 383         ib_fmr_batch_release(pool);
 384
 385         i = 0;
 386         list_for_each_entry_safe(fmr, tmp, &pool->free_list, list) {
 387                 ib_dealloc_fmr(fmr->fmr);
 388                 list_del(&fmr->list);
 389                 kfree(fmr);
 390                 ++i;
 391         }
 392
 393         if (i < pool->pool_size)
 394                 printk(KERN_WARNING PFX "pool still has %d regions registered\n",
 395                        pool->pool_size - i);
 396
 397         kfree(pool->cache_bucket);
 398         kfree(pool);
 399 }
 400 EXPORT_SYMBOL(ib_destroy_fmr_pool);
 401
 402 /**
 403  * ib_flush_fmr_pool - Invalidate all unmapped FMRs
 404  * @pool:FMR pool to flush
 405  *
 406  * Ensure that all unmapped FMRs are fully invalidated.
 407  */
 408 int ib_flush_fmr_pool(struct ib_fmr_pool *pool)
 409 {
 410         int serial = atomic_inc_return(&pool->req_ser);
 411
 412         wake_up_process(pool->thread);
 413
 414         if (wait_event_interruptible(pool->force_wait,
 415                                      atomic_read(&pool->flush_ser) - serial >= 0))
 416                 return -EINTR;
 417
 418         return 0;
 419 }
 420 EXPORT_SYMBOL(ib_flush_fmr_pool);
 421
 422 /**
 423  * ib_fmr_pool_map_phys -
 424  * @pool:FMR pool to allocate FMR from
 425  * @page_list:List of pages to map
 426  * @list_len:Number of pages in @page_list
 427  * @io_virtual_address:I/O virtual address for new FMR
 428  *
 429  * Map an FMR from an FMR pool.
 430  */
 431 struct ib_pool_fmr *ib_fmr_pool_map_phys(struct ib_fmr_pool *pool_handle,
 432                                          u64                *page_list,
 433                                          int                 list_len,
 434                                          u64                 io_virtual_address)
 435 {
 436         struct ib_fmr_pool *pool = pool_handle;
 437         struct ib_pool_fmr *fmr;
 438         unsigned long       flags;
 439         int                 result;
 440
 441         if (list_len < 1 || list_len > pool->max_pages)
 442                 return ERR_PTR(-EINVAL);
 443
 444         spin_lock_irqsave(&pool->pool_lock, flags);
 445         fmr = ib_fmr_cache_lookup(pool,
 446                                   page_list,
 447                                   list_len,
 448                                   io_virtual_address);
 449         if (fmr) {
 450                 /* found in cache */
 451                 ++fmr->ref_count;
 452                 if (fmr->ref_count == 1) {
 453                         list_del(&fmr->list);
 454                 }
 455
 456                 spin_unlock_irqrestore(&pool->pool_lock, flags);
 457
 458                 return fmr;
 459         }
 460
 461         if (list_empty(&pool->free_list)) {
 462                 spin_unlock_irqrestore(&pool->pool_lock, flags);
 463                 return ERR_PTR(-EAGAIN);
 464         }
 465
 466         fmr = list_entry(pool->free_list.next, struct ib_pool_fmr, list);
 467         list_del(&fmr->list);
 468         hlist_del_init(&fmr->cache_node);
 469         spin_unlock_irqrestore(&pool->pool_lock, flags);
 470
 471         result = ib_map_phys_fmr(fmr->fmr, page_list, list_len,
 472                                  io_virtual_address);
 473
 474         if (result) {
 475                 spin_lock_irqsave(&pool->pool_lock, flags);
 476                 list_add(&fmr->list, &pool->free_list);
 477                 spin_unlock_irqrestore(&pool->pool_lock, flags);
 478
 479                 printk(KERN_WARNING PFX "fmr_map returns %d\n", result);
 480
 481                 return ERR_PTR(result);
 482         }
 483
 484         ++fmr->remap_count;
 485         fmr->ref_count = 1;
 486
 487         if (pool->cache_bucket) {
 488                 fmr->io_virtual_address = io_virtual_address;
 489                 fmr->page_list_len      = list_len;
 490                 memcpy(fmr->page_list, page_list, list_len * sizeof(*page_list));
 491
 492                 spin_lock_irqsave(&pool->pool_lock, flags);
 493                 hlist_add_head(&fmr->cache_node,
 494                                pool->cache_bucket + ib_fmr_hash(fmr->page_list[0]));
 495                 spin_unlock_irqrestore(&pool->pool_lock, flags);
 496         }
 497
 498         return fmr;
 499 }
 500 EXPORT_SYMBOL(ib_fmr_pool_map_phys);
 501
 502 /**
 503  * ib_fmr_pool_unmap - Unmap FMR
 504  * @fmr:FMR to unmap
 505  *
 506  * Unmap an FMR.  The FMR mapping may remain valid until the FMR is
 507  * reused (or until ib_flush_fmr_pool() is called).
 508  */
 509 int ib_fmr_pool_unmap(struct ib_pool_fmr *fmr)
 510 {
 511         struct ib_fmr_pool *pool;
 512         unsigned long flags;
 513
 514         pool = fmr->pool;
 515
 516         spin_lock_irqsave(&pool->pool_lock, flags);
 517
 518         --fmr->ref_count;
 519         if (!fmr->ref_count) {
 520                 if (fmr->remap_count < pool->max_remaps) {
 521                         list_add_tail(&fmr->list, &pool->free_list);
 522                 } else {
 523                         list_add_tail(&fmr->list, &pool->dirty_list);
 524                         if (++pool->dirty_len >= pool->dirty_watermark) {
 525                                 atomic_inc(&pool->req_ser);
 526                                 wake_up_process(pool->thread);
 527                         }
 528                 }
 529         }
 530
 531 #ifdef DEBUG
 532         if (fmr->ref_count < 0)
 533                 printk(KERN_WARNING PFX "FMR %p has ref count %d < 0\n",
 534                        fmr, fmr->ref_count);
 535 #endif
 536
 537         spin_unlock_irqrestore(&pool->pool_lock, flags);
 538
 539         return 0;
 540 }
 541 EXPORT_SYMBOL(ib_fmr_pool_unmap);