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
  34 #include <linux/errno.h>
  35 #include <linux/spinlock.h>
  36 #include <linux/export.h>
  37 #include <linux/slab.h>
  38 #include <linux/jhash.h>
  39 #include <linux/kthread.h>
  40
  41 #include <rdma/ib_fmr_pool.h>
  42
  43 #include "core_priv.h"
  44
  45 #define PFX "fmr_pool: "
  46
  47 enum {
  48         IB_FMR_MAX_REMAPS = 32,
  49
  50         IB_FMR_HASH_BITS  = 8,
  51         IB_FMR_HASH_SIZE  = 1 << IB_FMR_HASH_BITS,
  52         IB_FMR_HASH_MASK  = IB_FMR_HASH_SIZE - 1
  53 };
  54
  55 /*
  56  * If an FMR is not in use, then the list member will point to either
  57  * its pool's free_list (if the FMR can be mapped again; that is,
  58  * remap_count < pool->max_remaps) or its pool's dirty_list (if the
  59  * FMR needs to be unmapped before being remapped).  In either of
  60  * these cases it is a bug if the ref_count is not 0.  In other words,
  61  * if ref_count is > 0, then the list member must not be linked into
  62  * either free_list or dirty_list.
  63  *
  64  * The cache_node member is used to link the FMR into a cache bucket
  65  * (if caching is enabled).  This is independent of the reference
  66  * count of the FMR.  When a valid FMR is released, its ref_count is
  67  * decremented, and if ref_count reaches 0, the FMR is placed in
  68  * either free_list or dirty_list as appropriate.  However, it is not
  69  * removed from the cache and may be "revived" if a call to
  70  * ib_fmr_register_physical() occurs before the FMR is remapped.  In
  71  * this case we just increment the ref_count and remove the FMR from
  72  * free_list/dirty_list.
  73  *
  74  * Before we remap an FMR from free_list, we remove it from the cache
  75  * (to prevent another user from obtaining a stale FMR).  When an FMR
  76  * is released, we add it to the tail of the free list, so that our
  77  * cache eviction policy is "least recently used."
  78  *
  79  * All manipulation of ref_count, list and cache_node is protected by
  80  * pool_lock to maintain consistency.
  81  */
  82
  83 struct ib_fmr_pool {
  84         spinlock_t                pool_lock;
  85
  86         int                       pool_size;
  87         int                       max_pages;
  88         int                       max_remaps;
  89         int                       dirty_watermark;
  90         int                       dirty_len;
  91         struct list_head          free_list;
  92         struct list_head          dirty_list;
  93         struct hlist_head        *cache_bucket;
  94
  95         void                     (*flush_function)(struct ib_fmr_pool *pool,
  96                                                    void *              arg);
  97         void                     *flush_arg;
  98
  99         struct kthread_worker     *worker;
 100         struct kthread_work       work;
 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
 123         if (!pool->cache_bucket)
 124                 return NULL;
 125
 126         bucket = pool->cache_bucket + ib_fmr_hash(*page_list);
 127
 128         hlist_for_each_entry(fmr, bucket, cache_node)
 129                 if (io_virtual_address == fmr->io_virtual_address &&
 130                     page_list_len      == fmr->page_list_len      &&
 131                     !memcmp(page_list, fmr->page_list,
 132                             page_list_len * sizeof *page_list))
 133                         return fmr;
 134
 135         return NULL;
 136 }
 137
 138 static void ib_fmr_batch_release(struct ib_fmr_pool *pool)
 139 {
 140         int                 ret;
 141         struct ib_pool_fmr *fmr;
 142         LIST_HEAD(unmap_list);
 143         LIST_HEAD(fmr_list);
 144
 145         spin_lock_irq(&pool->pool_lock);
 146
 147         list_for_each_entry(fmr, &pool->dirty_list, list) {
 148                 hlist_del_init(&fmr->cache_node);
 149                 fmr->remap_count = 0;
 150                 list_add_tail(&fmr->fmr->list, &fmr_list);
 151
 152 #ifdef DEBUG
 153                 if (fmr->ref_count !=0) {
 154                         pr_warn(PFX "Unmapping FMR 0x%08x with ref count %d\n",
 155                                 fmr, fmr->ref_count);
 156                 }
 157 #endif
 158         }
 159
 160         list_splice_init(&pool->dirty_list, &unmap_list);
 161         pool->dirty_len = 0;
 162
 163         spin_unlock_irq(&pool->pool_lock);
 164
 165         if (list_empty(&unmap_list)) {
 166                 return;
 167         }
 168
 169         ret = ib_unmap_fmr(&fmr_list);
 170         if (ret)
 171                 pr_warn(PFX "ib_unmap_fmr returned %d\n", ret);
 172
 173         spin_lock_irq(&pool->pool_lock);
 174         list_splice(&unmap_list, &pool->free_list);
 175         spin_unlock_irq(&pool->pool_lock);
 176 }
 177
 178 static void ib_fmr_cleanup_func(struct kthread_work *work)
 179 {
 180         struct ib_fmr_pool *pool = container_of(work, struct ib_fmr_pool, work);
 181
 182         ib_fmr_batch_release(pool);
 183         atomic_inc(&pool->flush_ser);
 184         wake_up_interruptible(&pool->force_wait);
 185
 186         if (pool->flush_function)
 187                 pool->flush_function(pool, pool->flush_arg);
 188
 189         if (atomic_read(&pool->flush_ser) - atomic_read(&pool->req_ser) < 0)
 190                 kthread_queue_work(pool->worker, &pool->work);
 191 }
 192
 193 /**
 194  * ib_create_fmr_pool - Create an FMR pool
 195  * @pd:Protection domain for FMRs
 196  * @params:FMR pool parameters
 197  *
 198  * Create a pool of FMRs.  Return value is pointer to new pool or
 199  * error code if creation failed.
 200  */
 201 struct ib_fmr_pool *ib_create_fmr_pool(struct ib_pd             *pd,
 202                                        struct ib_fmr_pool_param *params)
 203 {
 204         struct ib_device   *device;
 205         struct ib_fmr_pool *pool;
 206         int i;
 207         int ret;
 208         int max_remaps;
 209
 210         if (!params)
 211                 return ERR_PTR(-EINVAL);
 212
 213         device = pd->device;
 214         if (!device->ops.alloc_fmr    || !device->ops.dealloc_fmr  ||
 215             !device->ops.map_phys_fmr || !device->ops.unmap_fmr) {
 216                 dev_info(&device->dev, "Device does not support FMRs\n");
 217                 return ERR_PTR(-ENOSYS);
 218         }
 219
 220         if (!device->attrs.max_map_per_fmr)
 221                 max_remaps = IB_FMR_MAX_REMAPS;
 222         else
 223                 max_remaps = device->attrs.max_map_per_fmr;
 224
 225         pool = kmalloc(sizeof *pool, GFP_KERNEL);
 226         if (!pool)
 227                 return ERR_PTR(-ENOMEM);
 228
 229         pool->cache_bucket   = NULL;
 230         pool->flush_function = params->flush_function;
 231         pool->flush_arg      = params->flush_arg;
 232
 233         INIT_LIST_HEAD(&pool->free_list);
 234         INIT_LIST_HEAD(&pool->dirty_list);
 235
 236         if (params->cache) {
 237                 pool->cache_bucket =
 238                         kmalloc_array(IB_FMR_HASH_SIZE,
 239                                       sizeof(*pool->cache_bucket),
 240                                       GFP_KERNEL);
 241                 if (!pool->cache_bucket) {
 242                         ret = -ENOMEM;
 243                         goto out_free_pool;
 244                 }
 245
 246                 for (i = 0; i < IB_FMR_HASH_SIZE; ++i)
 247                         INIT_HLIST_HEAD(pool->cache_bucket + i);
 248         }
 249
 250         pool->pool_size       = 0;
 251         pool->max_pages       = params->max_pages_per_fmr;
 252         pool->max_remaps      = max_remaps;
 253         pool->dirty_watermark = params->dirty_watermark;
 254         pool->dirty_len       = 0;
 255         spin_lock_init(&pool->pool_lock);
 256         atomic_set(&pool->req_ser,   0);
 257         atomic_set(&pool->flush_ser, 0);
 258         init_waitqueue_head(&pool->force_wait);
 259
 260         pool->worker =
 261                 kthread_create_worker(0, "ib_fmr(%s)", dev_name(&device->dev));
 262         if (IS_ERR(pool->worker)) {
 263                 pr_warn(PFX "couldn't start cleanup kthread worker\n");
 264                 ret = PTR_ERR(pool->worker);
 265                 goto out_free_pool;
 266         }
 267         kthread_init_work(&pool->work, ib_fmr_cleanup_func);
 268
 269         {
 270                 struct ib_pool_fmr *fmr;
 271                 struct ib_fmr_attr fmr_attr = {
 272                         .max_pages  = params->max_pages_per_fmr,
 273                         .max_maps   = pool->max_remaps,
 274                         .page_shift = params->page_shift
 275                 };
 276                 int bytes_per_fmr = sizeof *fmr;
 277
 278                 if (pool->cache_bucket)
 279                         bytes_per_fmr += params->max_pages_per_fmr * sizeof (u64);
 280
 281                 for (i = 0; i < params->pool_size; ++i) {
 282                         fmr = kmalloc(bytes_per_fmr, GFP_KERNEL);
 283                         if (!fmr)
 284                                 goto out_fail;
 285
 286                         fmr->pool             = pool;
 287                         fmr->remap_count      = 0;
 288                         fmr->ref_count        = 0;
 289                         INIT_HLIST_NODE(&fmr->cache_node);
 290
 291                         fmr->fmr = ib_alloc_fmr(pd, params->access, &fmr_attr);
 292                         if (IS_ERR(fmr->fmr)) {
 293                                 pr_warn(PFX "fmr_create failed for FMR %d\n",
 294                                         i);
 295                                 kfree(fmr);
 296                                 goto out_fail;
 297                         }
 298
 299                         list_add_tail(&fmr->list, &pool->free_list);
 300                         ++pool->pool_size;
 301                 }
 302         }
 303
 304         return pool;
 305
 306  out_free_pool:
 307         kfree(pool->cache_bucket);
 308         kfree(pool);
 309
 310         return ERR_PTR(ret);
 311
 312  out_fail:
 313         ib_destroy_fmr_pool(pool);
 314
 315         return ERR_PTR(-ENOMEM);
 316 }
 317 EXPORT_SYMBOL(ib_create_fmr_pool);
 318
 319 /**
 320  * ib_destroy_fmr_pool - Free FMR pool
 321  * @pool:FMR pool to free
 322  *
 323  * Destroy an FMR pool and free all associated resources.
 324  */
 325 void ib_destroy_fmr_pool(struct ib_fmr_pool *pool)
 326 {
 327         struct ib_pool_fmr *fmr;
 328         struct ib_pool_fmr *tmp;
 329         LIST_HEAD(fmr_list);
 330         int                 i;
 331
 332         kthread_destroy_worker(pool->worker);
 333         ib_fmr_batch_release(pool);
 334
 335         i = 0;
 336         list_for_each_entry_safe(fmr, tmp, &pool->free_list, list) {
 337                 if (fmr->remap_count) {
 338                         INIT_LIST_HEAD(&fmr_list);
 339                         list_add_tail(&fmr->fmr->list, &fmr_list);
 340                         ib_unmap_fmr(&fmr_list);
 341                 }
 342                 ib_dealloc_fmr(fmr->fmr);
 343                 list_del(&fmr->list);
 344                 kfree(fmr);
 345                 ++i;
 346         }
 347
 348         if (i < pool->pool_size)
 349                 pr_warn(PFX "pool still has %d regions registered\n",
 350                         pool->pool_size - i);
 351
 352         kfree(pool->cache_bucket);
 353         kfree(pool);
 354 }
 355 EXPORT_SYMBOL(ib_destroy_fmr_pool);
 356
 357 /**
 358  * ib_flush_fmr_pool - Invalidate all unmapped FMRs
 359  * @pool:FMR pool to flush
 360  *
 361  * Ensure that all unmapped FMRs are fully invalidated.
 362  */
 363 int ib_flush_fmr_pool(struct ib_fmr_pool *pool)
 364 {
 365         int serial;
 366         struct ib_pool_fmr *fmr, *next;
 367
 368         /*
 369          * The free_list holds FMRs that may have been used
 370          * but have not been remapped enough times to be dirty.
 371          * Put them on the dirty list now so that the cleanup
 372          * thread will reap them too.
 373          */
 374         spin_lock_irq(&pool->pool_lock);
 375         list_for_each_entry_safe(fmr, next, &pool->free_list, list) {
 376                 if (fmr->remap_count > 0)
 377                         list_move(&fmr->list, &pool->dirty_list);
 378         }
 379         spin_unlock_irq(&pool->pool_lock);
 380
 381         serial = atomic_inc_return(&pool->req_ser);
 382         kthread_queue_work(pool->worker, &pool->work);
 383
 384         if (wait_event_interruptible(pool->force_wait,
 385                                      atomic_read(&pool->flush_ser) - serial >= 0))
 386                 return -EINTR;
 387
 388         return 0;
 389 }
 390 EXPORT_SYMBOL(ib_flush_fmr_pool);
 391
 392 /**
 393  * ib_fmr_pool_map_phys - Map an FMR from an FMR pool.
 394  * @pool_handle: FMR pool to allocate FMR from
 395  * @page_list: List of pages to map
 396  * @list_len: Number of pages in @page_list
 397  * @io_virtual_address: I/O virtual address for new FMR
 398  */
 399 struct ib_pool_fmr *ib_fmr_pool_map_phys(struct ib_fmr_pool *pool_handle,
 400                                          u64                *page_list,
 401                                          int                 list_len,
 402                                          u64                 io_virtual_address)
 403 {
 404         struct ib_fmr_pool *pool = pool_handle;
 405         struct ib_pool_fmr *fmr;
 406         unsigned long       flags;
 407         int                 result;
 408
 409         if (list_len < 1 || list_len > pool->max_pages)
 410                 return ERR_PTR(-EINVAL);
 411
 412         spin_lock_irqsave(&pool->pool_lock, flags);
 413         fmr = ib_fmr_cache_lookup(pool,
 414                                   page_list,
 415                                   list_len,
 416                                   io_virtual_address);
 417         if (fmr) {
 418                 /* found in cache */
 419                 ++fmr->ref_count;
 420                 if (fmr->ref_count == 1) {
 421                         list_del(&fmr->list);
 422                 }
 423
 424                 spin_unlock_irqrestore(&pool->pool_lock, flags);
 425
 426                 return fmr;
 427         }
 428
 429         if (list_empty(&pool->free_list)) {
 430                 spin_unlock_irqrestore(&pool->pool_lock, flags);
 431                 return ERR_PTR(-EAGAIN);
 432         }
 433
 434         fmr = list_entry(pool->free_list.next, struct ib_pool_fmr, list);
 435         list_del(&fmr->list);
 436         hlist_del_init(&fmr->cache_node);
 437         spin_unlock_irqrestore(&pool->pool_lock, flags);
 438
 439         result = ib_map_phys_fmr(fmr->fmr, page_list, list_len,
 440                                  io_virtual_address);
 441
 442         if (result) {
 443                 spin_lock_irqsave(&pool->pool_lock, flags);
 444                 list_add(&fmr->list, &pool->free_list);
 445                 spin_unlock_irqrestore(&pool->pool_lock, flags);
 446
 447                 pr_warn(PFX "fmr_map returns %d\n", 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 void 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 < pool->max_remaps) {
 489                         list_add_tail(&fmr->list, &pool->free_list);
 490                 } else {
 491                         list_add_tail(&fmr->list, &pool->dirty_list);
 492                         if (++pool->dirty_len >= pool->dirty_watermark) {
 493                                 atomic_inc(&pool->req_ser);
 494                                 kthread_queue_work(pool->worker, &pool->work);
 495                         }
 496                 }
 497         }
 498
 499 #ifdef DEBUG
 500         if (fmr->ref_count < 0)
 501                 pr_warn(PFX "FMR %p has ref count %d < 0\n",
 502                         fmr, fmr->ref_count);
 503 #endif
 504
 505         spin_unlock_irqrestore(&pool->pool_lock, flags);
 506 }
 507 EXPORT_SYMBOL(ib_fmr_pool_unmap);