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 enum {
  47         IB_FMR_MAX_REMAPS = 32,
  48
  49         IB_FMR_HASH_BITS  = 8,
  50         IB_FMR_HASH_SIZE  = 1 << IB_FMR_HASH_BITS,
  51         IB_FMR_HASH_MASK  = IB_FMR_HASH_SIZE - 1
  52 };
  53
  54 /*
  55  * If an FMR is not in use, then the list member will point to either
  56  * its pool's free_list (if the FMR can be mapped again; that is,
  57  * remap_count < pool->max_remaps) or its pool's dirty_list (if the
  58  * FMR needs to be unmapped before being remapped).  In either of
  59  * these cases it is a bug if the ref_count is not 0.  In other words,
  60  * if ref_count is > 0, then the list member must not be linked into
  61  * either free_list or dirty_list.
  62  *
  63  * The cache_node member is used to link the FMR into a cache bucket
  64  * (if caching is enabled).  This is independent of the reference
  65  * count of the FMR.  When a valid FMR is released, its ref_count is
  66  * decremented, and if ref_count reaches 0, the FMR is placed in
  67  * either free_list or dirty_list as appropriate.  However, it is not
  68  * removed from the cache and may be "revived" if a call to
  69  * ib_fmr_register_physical() occurs before the FMR is remapped.  In
  70  * this case we just increment the ref_count and remove the FMR from
  71  * free_list/dirty_list.
  72  *
  73  * Before we remap an FMR from free_list, we remove it from the cache
  74  * (to prevent another user from obtaining a stale FMR).  When an FMR
  75  * is released, we add it to the tail of the free list, so that our
  76  * cache eviction policy is "least recently used."
  77  *
  78  * All manipulation of ref_count, list and cache_node is protected by
  79  * pool_lock to maintain consistency.
  80  */
  81
  82 struct ib_fmr_pool {
  83         spinlock_t                pool_lock;
  84
  85         int                       pool_size;
  86         int                       max_pages;
  87         int                       max_remaps;
  88         int                       dirty_watermark;
  89         int                       dirty_len;
  90         struct list_head          free_list;
  91         struct list_head          dirty_list;
  92         struct hlist_head        *cache_bucket;
  93
  94         void                     (*flush_function)(struct ib_fmr_pool *pool,
  95                                                    void *              arg);
  96         void                     *flush_arg;
  97
  98         struct task_struct       *thread;
  99
 100         atomic_t                  req_ser;
 101         atomic_t                  flush_ser;
 102
 103         wait_queue_head_t         force_wait;
 104 };
 105
 106 static inline u32 ib_fmr_hash(u64 first_page)
 107 {
 108         return jhash_2words((u32) first_page, (u32) (first_page >> 32), 0) &
 109                 (IB_FMR_HASH_SIZE - 1);
 110 }
 111
 112 /* Caller must hold pool_lock */
 113 static inline struct ib_pool_fmr *ib_fmr_cache_lookup(struct ib_fmr_pool *pool,
 114                                                       u64 *page_list,
 115                                                       int  page_list_len,
 116                                                       u64  io_virtual_address)
 117 {
 118         struct hlist_head *bucket;
 119         struct ib_pool_fmr *fmr;
 120         struct hlist_node *pos;
 121
 122         if (!pool->cache_bucket)
 123                 return NULL;
 124
 125         bucket = pool->cache_bucket + ib_fmr_hash(*page_list);
 126
 127         hlist_for_each_entry(fmr, pos, bucket, cache_node)
 128                 if (io_virtual_address == fmr->io_virtual_address &&
 129                     page_list_len      == fmr->page_list_len      &&
 130                     !memcmp(page_list, fmr->page_list,
 131                             page_list_len * sizeof *page_list))
 132                         return fmr;
 133
 134         return NULL;
 135 }
 136
 137 static void ib_fmr_batch_release(struct ib_fmr_pool *pool)
 138 {
 139         int                 ret;
 140         struct ib_pool_fmr *fmr;
 141         LIST_HEAD(unmap_list);
 142         LIST_HEAD(fmr_list);
 143
 144         spin_lock_irq(&pool->pool_lock);
 145
 146         list_for_each_entry(fmr, &pool->dirty_list, list) {
 147                 hlist_del_init(&fmr->cache_node);
 148                 fmr->remap_count = 0;
 149                 list_add_tail(&fmr->fmr->list, &fmr_list);
 150
 151 #ifdef DEBUG
 152                 if (fmr->ref_count !=0) {
 153                         printk(KERN_WARNING "Unmapping FMR 0x%08x with ref count %d",
 154                                fmr, fmr->ref_count);
 155                 }
 156 #endif
 157         }
 158
 159         list_splice(&pool->dirty_list, &unmap_list);
 160         INIT_LIST_HEAD(&pool->dirty_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                 printk(KERN_WARNING "ib_unmap_fmr returned %d", 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 int ib_fmr_cleanup_thread(void *pool_ptr)
 179 {
 180         struct ib_fmr_pool *pool = pool_ptr;
 181
 182         do {
 183                 if (pool->dirty_len >= pool->dirty_watermark ||
 184                     atomic_read(&pool->flush_ser) - atomic_read(&pool->req_ser) < 0) {
 185                         ib_fmr_batch_release(pool);
 186
 187                         atomic_inc(&pool->flush_ser);
 188                         wake_up_interruptible(&pool->force_wait);
 189
 190                         if (pool->flush_function)
 191                                 pool->flush_function(pool, pool->flush_arg);
 192                 }
 193
 194                 set_current_state(TASK_INTERRUPTIBLE);
 195                 if (pool->dirty_len < pool->dirty_watermark &&
 196                     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_WARNING "Device %s does not support fast memory regions",
 230                        device->name);
 231                 return ERR_PTR(-ENOSYS);
 232         }
 233
 234         attr = kmalloc(sizeof *attr, GFP_KERNEL);
 235         if (!attr) {
 236                 printk(KERN_WARNING "couldn't allocate device attr struct");
 237                 return ERR_PTR(-ENOMEM);
 238         }
 239
 240         ret = ib_query_device(device, attr);
 241         if (ret) {
 242                 printk(KERN_WARNING "couldn't query device");
 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 "couldn't allocate pool struct");
 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 "Failed to allocate cache in pool");
 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_create(ib_fmr_cleanup_thread,
 293                                       pool,
 294                                       "ib_fmr(%s)",
 295                                       device->name);
 296         if (IS_ERR(pool->thread)) {
 297                 printk(KERN_WARNING "couldn't start cleanup thread");
 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
 310                 for (i = 0; i < params->pool_size; ++i) {
 311                         fmr = kmalloc(sizeof *fmr + params->max_pages_per_fmr * sizeof (u64),
 312                                       GFP_KERNEL);
 313                         if (!fmr) {
 314                                 printk(KERN_WARNING "failed to allocate fmr struct "
 315                                        "for FMR %d", i);
 316                                 goto out_fail;
 317                         }
 318
 319                         fmr->pool             = pool;
 320                         fmr->remap_count      = 0;
 321                         fmr->ref_count        = 0;
 322                         INIT_HLIST_NODE(&fmr->cache_node);
 323
 324                         fmr->fmr = ib_alloc_fmr(pd, params->access, &fmr_attr);
 325                         if (IS_ERR(fmr->fmr)) {
 326                                 printk(KERN_WARNING "fmr_create failed for FMR %d", i);
 327                                 kfree(fmr);
 328                                 goto out_fail;
 329                         }
 330
 331                         list_add_tail(&fmr->list, &pool->free_list);
 332                         ++pool->pool_size;
 333                 }
 334         }
 335
 336         return pool;
 337
 338  out_free_pool:
 339         kfree(pool->cache_bucket);
 340         kfree(pool);
 341
 342         return ERR_PTR(ret);
 343
 344  out_fail:
 345         ib_destroy_fmr_pool(pool);
 346
 347         return ERR_PTR(-ENOMEM);
 348 }
 349 EXPORT_SYMBOL(ib_create_fmr_pool);
 350
 351 /**
 352  * ib_destroy_fmr_pool - Free FMR pool
 353  * @pool:FMR pool to free
 354  *
 355  * Destroy an FMR pool and free all associated resources.
 356  */
 357 void ib_destroy_fmr_pool(struct ib_fmr_pool *pool)
 358 {
 359         struct ib_pool_fmr *fmr;
 360         struct ib_pool_fmr *tmp;
 361         LIST_HEAD(fmr_list);
 362         int                 i;
 363
 364         kthread_stop(pool->thread);
 365         ib_fmr_batch_release(pool);
 366
 367         i = 0;
 368         list_for_each_entry_safe(fmr, tmp, &pool->free_list, list) {
 369                 if (fmr->remap_count) {
 370                         INIT_LIST_HEAD(&fmr_list);
 371                         list_add_tail(&fmr->fmr->list, &fmr_list);
 372                         ib_unmap_fmr(&fmr_list);
 373                 }
 374                 ib_dealloc_fmr(fmr->fmr);
 375                 list_del(&fmr->list);
 376                 kfree(fmr);
 377                 ++i;
 378         }
 379
 380         if (i < pool->pool_size)
 381                 printk(KERN_WARNING "pool still has %d regions registered",
 382                        pool->pool_size - i);
 383
 384         kfree(pool->cache_bucket);
 385         kfree(pool);
 386 }
 387 EXPORT_SYMBOL(ib_destroy_fmr_pool);
 388
 389 /**
 390  * ib_flush_fmr_pool - Invalidate all unmapped FMRs
 391  * @pool:FMR pool to flush
 392  *
 393  * Ensure that all unmapped FMRs are fully invalidated.
 394  */
 395 int ib_flush_fmr_pool(struct ib_fmr_pool *pool)
 396 {
 397         int serial = atomic_inc_return(&pool->req_ser);
 398
 399         wake_up_process(pool->thread);
 400
 401         if (wait_event_interruptible(pool->force_wait,
 402                                      atomic_read(&pool->flush_ser) - serial >= 0))
 403                 return -EINTR;
 404
 405         return 0;
 406 }
 407 EXPORT_SYMBOL(ib_flush_fmr_pool);
 408
 409 /**
 410  * ib_fmr_pool_map_phys -
 411  * @pool:FMR pool to allocate FMR from
 412  * @page_list:List of pages to map
 413  * @list_len:Number of pages in @page_list
 414  * @io_virtual_address:I/O virtual address for new FMR
 415  *
 416  * Map an FMR from an FMR pool.
 417  */
 418 struct ib_pool_fmr *ib_fmr_pool_map_phys(struct ib_fmr_pool *pool_handle,
 419                                          u64                *page_list,
 420                                          int                 list_len,
 421                                          u64                 io_virtual_address)
 422 {
 423         struct ib_fmr_pool *pool = pool_handle;
 424         struct ib_pool_fmr *fmr;
 425         unsigned long       flags;
 426         int                 result;
 427
 428         if (list_len < 1 || list_len > pool->max_pages)
 429                 return ERR_PTR(-EINVAL);
 430
 431         spin_lock_irqsave(&pool->pool_lock, flags);
 432         fmr = ib_fmr_cache_lookup(pool,
 433                                   page_list,
 434                                   list_len,
 435                                   io_virtual_address);
 436         if (fmr) {
 437                 /* found in cache */
 438                 ++fmr->ref_count;
 439                 if (fmr->ref_count == 1) {
 440                         list_del(&fmr->list);
 441                 }
 442
 443                 spin_unlock_irqrestore(&pool->pool_lock, flags);
 444
 445                 return fmr;
 446         }
 447
 448         if (list_empty(&pool->free_list)) {
 449                 spin_unlock_irqrestore(&pool->pool_lock, flags);
 450                 return ERR_PTR(-EAGAIN);
 451         }
 452
 453         fmr = list_entry(pool->free_list.next, struct ib_pool_fmr, list);
 454         list_del(&fmr->list);
 455         hlist_del_init(&fmr->cache_node);
 456         spin_unlock_irqrestore(&pool->pool_lock, flags);
 457
 458         result = ib_map_phys_fmr(fmr->fmr, page_list, list_len,
 459                                  io_virtual_address);
 460
 461         if (result) {
 462                 spin_lock_irqsave(&pool->pool_lock, flags);
 463                 list_add(&fmr->list, &pool->free_list);
 464                 spin_unlock_irqrestore(&pool->pool_lock, flags);
 465
 466                 printk(KERN_WARNING "fmr_map returns %d\n",
 467                        result);
 468
 469                 return ERR_PTR(result);
 470         }
 471
 472         ++fmr->remap_count;
 473         fmr->ref_count = 1;
 474
 475         if (pool->cache_bucket) {
 476                 fmr->io_virtual_address = io_virtual_address;
 477                 fmr->page_list_len      = list_len;
 478                 memcpy(fmr->page_list, page_list, list_len * sizeof(*page_list));
 479
 480                 spin_lock_irqsave(&pool->pool_lock, flags);
 481                 hlist_add_head(&fmr->cache_node,
 482                                pool->cache_bucket + ib_fmr_hash(fmr->page_list[0]));
 483                 spin_unlock_irqrestore(&pool->pool_lock, flags);
 484         }
 485
 486         return fmr;
 487 }
 488 EXPORT_SYMBOL(ib_fmr_pool_map_phys);
 489
 490 /**
 491  * ib_fmr_pool_unmap - Unmap FMR
 492  * @fmr:FMR to unmap
 493  *
 494  * Unmap an FMR.  The FMR mapping may remain valid until the FMR is
 495  * reused (or until ib_flush_fmr_pool() is called).
 496  */
 497 int ib_fmr_pool_unmap(struct ib_pool_fmr *fmr)
 498 {
 499         struct ib_fmr_pool *pool;
 500         unsigned long flags;
 501
 502         pool = fmr->pool;
 503
 504         spin_lock_irqsave(&pool->pool_lock, flags);
 505
 506         --fmr->ref_count;
 507         if (!fmr->ref_count) {
 508                 if (fmr->remap_count < pool->max_remaps) {
 509                         list_add_tail(&fmr->list, &pool->free_list);
 510                 } else {
 511                         list_add_tail(&fmr->list, &pool->dirty_list);
 512                         ++pool->dirty_len;
 513                         wake_up_process(pool->thread);
 514                 }
 515         }
 516
 517 #ifdef DEBUG
 518         if (fmr->ref_count < 0)
 519                 printk(KERN_WARNING "FMR %p has ref count %d < 0",
 520                        fmr, fmr->ref_count);
 521 #endif
 522
 523         spin_unlock_irqrestore(&pool->pool_lock, flags);
 524
 525         return 0;
 526 }
 527 EXPORT_SYMBOL(ib_fmr_pool_unmap);