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/slab.h>
  37 #include <linux/jhash.h>
  38 #include <linux/kthread.h>
  39
  40 #include <rdma/ib_fmr_pool.h>
  41
  42 #include "core_priv.h"
  43
  44 #define PFX "fmr_pool: "
  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 PFX "Unmapping FMR 0x%08x with ref count %d\n",
 154                                fmr, fmr->ref_count);
 155                 }
 156 #endif
 157         }
 158
 159         list_splice_init(&pool->dirty_list, &unmap_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 PFX "ib_unmap_fmr returned %d\n", 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 (atomic_read(&pool->flush_ser) - atomic_read(&pool->req_ser) < 0) {
 183                         ib_fmr_batch_release(pool);
 184
 185                         atomic_inc(&pool->flush_ser);
 186                         wake_up_interruptible(&pool->force_wait);
 187
 188                         if (pool->flush_function)
 189                                 pool->flush_function(pool, pool->flush_arg);
 190                 }
 191
 192                 set_current_state(TASK_INTERRUPTIBLE);
 193                 if (atomic_read(&pool->flush_ser) - atomic_read(&pool->req_ser) >= 0 &&
 194                     !kthread_should_stop())
 195                         schedule();
 196                 __set_current_state(TASK_RUNNING);
 197         } while (!kthread_should_stop());
 198
 199         return 0;
 200 }
 201
 202 /**
 203  * ib_create_fmr_pool - Create an FMR pool
 204  * @pd:Protection domain for FMRs
 205  * @params:FMR pool parameters
 206  *
 207  * Create a pool of FMRs.  Return value is pointer to new pool or
 208  * error code if creation failed.
 209  */
 210 struct ib_fmr_pool *ib_create_fmr_pool(struct ib_pd             *pd,
 211                                        struct ib_fmr_pool_param *params)
 212 {
 213         struct ib_device   *device;
 214         struct ib_fmr_pool *pool;
 215         struct ib_device_attr *attr;
 216         int i;
 217         int ret;
 218         int max_remaps;
 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_INFO PFX "Device %s does not support FMRs\n",
 227                        device->name);
 228                 return ERR_PTR(-ENOSYS);
 229         }
 230
 231         attr = kmalloc(sizeof *attr, GFP_KERNEL);
 232         if (!attr) {
 233                 printk(KERN_WARNING PFX "couldn't allocate device attr struct\n");
 234                 return ERR_PTR(-ENOMEM);
 235         }
 236
 237         ret = ib_query_device(device, attr);
 238         if (ret) {
 239                 printk(KERN_WARNING PFX "couldn't query device: %d\n", ret);
 240                 kfree(attr);
 241                 return ERR_PTR(ret);
 242         }
 243
 244         if (!attr->max_map_per_fmr)
 245                 max_remaps = IB_FMR_MAX_REMAPS;
 246         else
 247                 max_remaps = attr->max_map_per_fmr;
 248
 249         kfree(attr);
 250
 251         pool = kmalloc(sizeof *pool, GFP_KERNEL);
 252         if (!pool) {
 253                 printk(KERN_WARNING PFX "couldn't allocate pool struct\n");
 254                 return ERR_PTR(-ENOMEM);
 255         }
 256
 257         pool->cache_bucket   = NULL;
 258
 259         pool->flush_function = params->flush_function;
 260         pool->flush_arg      = params->flush_arg;
 261
 262         INIT_LIST_HEAD(&pool->free_list);
 263         INIT_LIST_HEAD(&pool->dirty_list);
 264
 265         if (params->cache) {
 266                 pool->cache_bucket =
 267                         kmalloc(IB_FMR_HASH_SIZE * sizeof *pool->cache_bucket,
 268                                 GFP_KERNEL);
 269                 if (!pool->cache_bucket) {
 270                         printk(KERN_WARNING PFX "Failed to allocate cache in pool\n");
 271                         ret = -ENOMEM;
 272                         goto out_free_pool;
 273                 }
 274
 275                 for (i = 0; i < IB_FMR_HASH_SIZE; ++i)
 276                         INIT_HLIST_HEAD(pool->cache_bucket + i);
 277         }
 278
 279         pool->pool_size       = 0;
 280         pool->max_pages       = params->max_pages_per_fmr;
 281         pool->max_remaps      = max_remaps;
 282         pool->dirty_watermark = params->dirty_watermark;
 283         pool->dirty_len       = 0;
 284         spin_lock_init(&pool->pool_lock);
 285         atomic_set(&pool->req_ser,   0);
 286         atomic_set(&pool->flush_ser, 0);
 287         init_waitqueue_head(&pool->force_wait);
 288
 289         pool->thread = kthread_run(ib_fmr_cleanup_thread,
 290                                    pool,
 291                                    "ib_fmr(%s)",
 292                                    device->name);
 293         if (IS_ERR(pool->thread)) {
 294                 printk(KERN_WARNING PFX "couldn't start cleanup thread\n");
 295                 ret = PTR_ERR(pool->thread);
 296                 goto out_free_pool;
 297         }
 298
 299         {
 300                 struct ib_pool_fmr *fmr;
 301                 struct ib_fmr_attr fmr_attr = {
 302                         .max_pages  = params->max_pages_per_fmr,
 303                         .max_maps   = pool->max_remaps,
 304                         .page_shift = params->page_shift
 305                 };
 306                 int bytes_per_fmr = sizeof *fmr;
 307
 308                 if (pool->cache_bucket)
 309                         bytes_per_fmr += params->max_pages_per_fmr * sizeof (u64);
 310
 311                 for (i = 0; i < params->pool_size; ++i) {
 312                         fmr = kmalloc(bytes_per_fmr, GFP_KERNEL);
 313                         if (!fmr) {
 314                                 printk(KERN_WARNING PFX "failed to allocate fmr "
 315                                        "struct for FMR %d\n", 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 PFX "fmr_create failed "
 327                                        "for FMR %d\n", i);
 328                                 kfree(fmr);
 329                                 goto out_fail;
 330                         }
 331
 332                         list_add_tail(&fmr->list, &pool->free_list);
 333                         ++pool->pool_size;
 334                 }
 335         }
 336
 337         return pool;
 338
 339  out_free_pool:
 340         kfree(pool->cache_bucket);
 341         kfree(pool);
 342
 343         return ERR_PTR(ret);
 344
 345  out_fail:
 346         ib_destroy_fmr_pool(pool);
 347
 348         return ERR_PTR(-ENOMEM);
 349 }
 350 EXPORT_SYMBOL(ib_create_fmr_pool);
 351
 352 /**
 353  * ib_destroy_fmr_pool - Free FMR pool
 354  * @pool:FMR pool to free
 355  *
 356  * Destroy an FMR pool and free all associated resources.
 357  */
 358 void ib_destroy_fmr_pool(struct ib_fmr_pool *pool)
 359 {
 360         struct ib_pool_fmr *fmr;
 361         struct ib_pool_fmr *tmp;
 362         LIST_HEAD(fmr_list);
 363         int                 i;
 364
 365         kthread_stop(pool->thread);
 366         ib_fmr_batch_release(pool);
 367
 368         i = 0;
 369         list_for_each_entry_safe(fmr, tmp, &pool->free_list, list) {
 370                 if (fmr->remap_count) {
 371                         INIT_LIST_HEAD(&fmr_list);
 372                         list_add_tail(&fmr->fmr->list, &fmr_list);
 373                         ib_unmap_fmr(&fmr_list);
 374                 }
 375                 ib_dealloc_fmr(fmr->fmr);
 376                 list_del(&fmr->list);
 377                 kfree(fmr);
 378                 ++i;
 379         }
 380
 381         if (i < pool->pool_size)
 382                 printk(KERN_WARNING PFX "pool still has %d regions registered\n",
 383                        pool->pool_size - i);
 384
 385         kfree(pool->cache_bucket);
 386         kfree(pool);
 387 }
 388 EXPORT_SYMBOL(ib_destroy_fmr_pool);
 389
 390 /**
 391  * ib_flush_fmr_pool - Invalidate all unmapped FMRs
 392  * @pool:FMR pool to flush
 393  *
 394  * Ensure that all unmapped FMRs are fully invalidated.
 395  */
 396 int ib_flush_fmr_pool(struct ib_fmr_pool *pool)
 397 {
 398         int serial;
 399         struct ib_pool_fmr *fmr, *next;
 400
 401         /*
 402          * The free_list holds FMRs that may have been used
 403          * but have not been remapped enough times to be dirty.
 404          * Put them on the dirty list now so that the cleanup
 405          * thread will reap them too.
 406          */
 407         spin_lock_irq(&pool->pool_lock);
 408         list_for_each_entry_safe(fmr, next, &pool->free_list, list) {
 409                 if (fmr->remap_count > 0)
 410                         list_move(&fmr->list, &pool->dirty_list);
 411         }
 412         spin_unlock_irq(&pool->pool_lock);
 413
 414         serial = atomic_inc_return(&pool->req_ser);
 415         wake_up_process(pool->thread);
 416
 417         if (wait_event_interruptible(pool->force_wait,
 418                                      atomic_read(&pool->flush_ser) - serial >= 0))
 419                 return -EINTR;
 420
 421         return 0;
 422 }
 423 EXPORT_SYMBOL(ib_flush_fmr_pool);
 424
 425 /**
 426  * ib_fmr_pool_map_phys -
 427  * @pool:FMR pool to allocate FMR from
 428  * @page_list:List of pages to map
 429  * @list_len:Number of pages in @page_list
 430  * @io_virtual_address:I/O virtual address for new FMR
 431  *
 432  * Map an FMR from an FMR pool.
 433  */
 434 struct ib_pool_fmr *ib_fmr_pool_map_phys(struct ib_fmr_pool *pool_handle,
 435                                          u64                *page_list,
 436                                          int                 list_len,
 437                                          u64                 io_virtual_address)
 438 {
 439         struct ib_fmr_pool *pool = pool_handle;
 440         struct ib_pool_fmr *fmr;
 441         unsigned long       flags;
 442         int                 result;
 443
 444         if (list_len < 1 || list_len > pool->max_pages)
 445                 return ERR_PTR(-EINVAL);
 446
 447         spin_lock_irqsave(&pool->pool_lock, flags);
 448         fmr = ib_fmr_cache_lookup(pool,
 449                                   page_list,
 450                                   list_len,
 451                                   io_virtual_address);
 452         if (fmr) {
 453                 /* found in cache */
 454                 ++fmr->ref_count;
 455                 if (fmr->ref_count == 1) {
 456                         list_del(&fmr->list);
 457                 }
 458
 459                 spin_unlock_irqrestore(&pool->pool_lock, flags);
 460
 461                 return fmr;
 462         }
 463
 464         if (list_empty(&pool->free_list)) {
 465                 spin_unlock_irqrestore(&pool->pool_lock, flags);
 466                 return ERR_PTR(-EAGAIN);
 467         }
 468
 469         fmr = list_entry(pool->free_list.next, struct ib_pool_fmr, list);
 470         list_del(&fmr->list);
 471         hlist_del_init(&fmr->cache_node);
 472         spin_unlock_irqrestore(&pool->pool_lock, flags);
 473
 474         result = ib_map_phys_fmr(fmr->fmr, page_list, list_len,
 475                                  io_virtual_address);
 476
 477         if (result) {
 478                 spin_lock_irqsave(&pool->pool_lock, flags);
 479                 list_add(&fmr->list, &pool->free_list);
 480                 spin_unlock_irqrestore(&pool->pool_lock, flags);
 481
 482                 printk(KERN_WARNING PFX "fmr_map returns %d\n", result);
 483
 484                 return ERR_PTR(result);
 485         }
 486
 487         ++fmr->remap_count;
 488         fmr->ref_count = 1;
 489
 490         if (pool->cache_bucket) {
 491                 fmr->io_virtual_address = io_virtual_address;
 492                 fmr->page_list_len      = list_len;
 493                 memcpy(fmr->page_list, page_list, list_len * sizeof(*page_list));
 494
 495                 spin_lock_irqsave(&pool->pool_lock, flags);
 496                 hlist_add_head(&fmr->cache_node,
 497                                pool->cache_bucket + ib_fmr_hash(fmr->page_list[0]));
 498                 spin_unlock_irqrestore(&pool->pool_lock, flags);
 499         }
 500
 501         return fmr;
 502 }
 503 EXPORT_SYMBOL(ib_fmr_pool_map_phys);
 504
 505 /**
 506  * ib_fmr_pool_unmap - Unmap FMR
 507  * @fmr:FMR to unmap
 508  *
 509  * Unmap an FMR.  The FMR mapping may remain valid until the FMR is
 510  * reused (or until ib_flush_fmr_pool() is called).
 511  */
 512 int ib_fmr_pool_unmap(struct ib_pool_fmr *fmr)
 513 {
 514         struct ib_fmr_pool *pool;
 515         unsigned long flags;
 516
 517         pool = fmr->pool;
 518
 519         spin_lock_irqsave(&pool->pool_lock, flags);
 520
 521         --fmr->ref_count;
 522         if (!fmr->ref_count) {
 523                 if (fmr->remap_count < pool->max_remaps) {
 524                         list_add_tail(&fmr->list, &pool->free_list);
 525                 } else {
 526                         list_add_tail(&fmr->list, &pool->dirty_list);
 527                         if (++pool->dirty_len >= pool->dirty_watermark) {
 528                                 atomic_inc(&pool->req_ser);
 529                                 wake_up_process(pool->thread);
 530                         }
 531                 }
 532         }
 533
 534 #ifdef DEBUG
 535         if (fmr->ref_count < 0)
 536                 printk(KERN_WARNING PFX "FMR %p has ref count %d < 0\n",
 537                        fmr, fmr->ref_count);
 538 #endif
 539
 540         spin_unlock_irqrestore(&pool->pool_lock, flags);
 541
 542         return 0;
 543 }
 544 EXPORT_SYMBOL(ib_fmr_pool_unmap);