sys/ofed/drivers/infiniband/core/ib_fmr_pool.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-2-Clause OR GPL-2.0
   3  *
   4  * Copyright (c) 2004 Topspin Communications.  All rights reserved.
   5  * Copyright (c) 2005 Sun Microsystems, Inc. All rights reserved.
   6  *
   7  * This software is available to you under a choice of one of two
   8  * licenses.  You may choose to be licensed under the terms of the GNU
   9  * General Public License (GPL) Version 2, available from the file
  10  * COPYING in the main directory of this source tree, or the
  11  * OpenIB.org BSD license below:
  12  *
  13  *     Redistribution and use in source and binary forms, with or
  14  *     without modification, are permitted provided that the following
  15  *     conditions are met:
  16  *
  17  *      - Redistributions of source code must retain the above
  18  *        copyright notice, this list of conditions and the following
  19  *        disclaimer.
  20  *
  21  *      - Redistributions in binary form must reproduce the above
  22  *        copyright notice, this list of conditions and the following
  23  *        disclaimer in the documentation and/or other materials
  24  *        provided with the distribution.
  25  *
  26  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  27  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  28  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  29  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  30  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  31  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  32  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  33  * SOFTWARE.
  34  */
  35
  36 #include <sys/cdefs.h>
  37 __FBSDID("$FreeBSD$");
  38
  39 #include <linux/errno.h>
  40 #include <linux/spinlock.h>
  41 #include <linux/slab.h>
  42 #include <linux/jhash.h>
  43 #include <linux/kthread.h>
  44 #include <linux/wait.h>
  45
  46 #include <rdma/ib_fmr_pool.h>
  47
  48 #include "core_priv.h"
  49
  50 #define PFX "fmr_pool: "
  51
  52 enum {
  53         IB_FMR_MAX_REMAPS = 32,
  54
  55         IB_FMR_HASH_BITS  = 8,
  56         IB_FMR_HASH_SIZE  = 1 << IB_FMR_HASH_BITS,
  57         IB_FMR_HASH_MASK  = IB_FMR_HASH_SIZE - 1
  58 };
  59
  60 /*
  61  * If an FMR is not in use, then the list member will point to either
  62  * its pool's free_list (if the FMR can be mapped again; that is,
  63  * remap_count < pool->max_remaps) or its pool's dirty_list (if the
  64  * FMR needs to be unmapped before being remapped).  In either of
  65  * these cases it is a bug if the ref_count is not 0.  In other words,
  66  * if ref_count is > 0, then the list member must not be linked into
  67  * either free_list or dirty_list.
  68  *
  69  * The cache_node member is used to link the FMR into a cache bucket
  70  * (if caching is enabled).  This is independent of the reference
  71  * count of the FMR.  When a valid FMR is released, its ref_count is
  72  * decremented, and if ref_count reaches 0, the FMR is placed in
  73  * either free_list or dirty_list as appropriate.  However, it is not
  74  * removed from the cache and may be "revived" if a call to
  75  * ib_fmr_register_physical() occurs before the FMR is remapped.  In
  76  * this case we just increment the ref_count and remove the FMR from
  77  * free_list/dirty_list.
  78  *
  79  * Before we remap an FMR from free_list, we remove it from the cache
  80  * (to prevent another user from obtaining a stale FMR).  When an FMR
  81  * is released, we add it to the tail of the free list, so that our
  82  * cache eviction policy is "least recently used."
  83  *
  84  * All manipulation of ref_count, list and cache_node is protected by
  85  * pool_lock to maintain consistency.
  86  */
  87
  88 struct ib_fmr_pool {
  89         spinlock_t                pool_lock;
  90
  91         int                       pool_size;
  92         int                       max_pages;
  93         int                       max_remaps;
  94         int                       dirty_watermark;
  95         int                       dirty_len;
  96         struct list_head          free_list;
  97         struct list_head          dirty_list;
  98         struct hlist_head        *cache_bucket;
  99
 100         void                     (*flush_function)(struct ib_fmr_pool *pool,
 101                                                    void *              arg);
 102         void                     *flush_arg;
 103
 104         struct task_struct       *thread;
 105
 106         atomic_t                  req_ser;
 107         atomic_t                  flush_ser;
 108
 109         wait_queue_head_t         force_wait;
 110 };
 111
 112 static inline u32 ib_fmr_hash(u64 first_page)
 113 {
 114         return jhash_2words((u32) first_page, (u32) (first_page >> 32), 0) &
 115                 (IB_FMR_HASH_SIZE - 1);
 116 }
 117
 118 /* Caller must hold pool_lock */
 119 static inline struct ib_pool_fmr *ib_fmr_cache_lookup(struct ib_fmr_pool *pool,
 120                                                       u64 *page_list,
 121                                                       int  page_list_len,
 122                                                       u64  io_virtual_address)
 123 {
 124         struct hlist_head *bucket;
 125         struct ib_pool_fmr *fmr;
 126
 127         if (!pool->cache_bucket)
 128                 return NULL;
 129
 130         bucket = pool->cache_bucket + ib_fmr_hash(*page_list);
 131
 132         hlist_for_each_entry(fmr, bucket, cache_node)
 133                 if (io_virtual_address == fmr->io_virtual_address &&
 134                     page_list_len      == fmr->page_list_len      &&
 135                     !memcmp(page_list, fmr->page_list,
 136                             page_list_len * sizeof *page_list))
 137                         return fmr;
 138
 139         return NULL;
 140 }
 141
 142 static void ib_fmr_batch_release(struct ib_fmr_pool *pool)
 143 {
 144         int                 ret;
 145         struct ib_pool_fmr *fmr;
 146         LIST_HEAD(unmap_list);
 147         LIST_HEAD(fmr_list);
 148
 149         spin_lock_irq(&pool->pool_lock);
 150
 151         list_for_each_entry(fmr, &pool->dirty_list, list) {
 152                 hlist_del_init(&fmr->cache_node);
 153                 fmr->remap_count = 0;
 154                 list_add_tail(&fmr->fmr->list, &fmr_list);
 155
 156 #ifdef DEBUG
 157                 if (fmr->ref_count !=0) {
 158                         pr_warn(PFX "Unmapping FMR %p with ref count %d\n",
 159                                 fmr, fmr->ref_count);
 160                 }
 161 #endif
 162         }
 163
 164         list_splice_init(&pool->dirty_list, &unmap_list);
 165         pool->dirty_len = 0;
 166
 167         spin_unlock_irq(&pool->pool_lock);
 168
 169         if (list_empty(&unmap_list)) {
 170                 return;
 171         }
 172
 173         ret = ib_unmap_fmr(&fmr_list);
 174         if (ret)
 175                 pr_warn(PFX "ib_unmap_fmr returned %d\n", ret);
 176
 177         spin_lock_irq(&pool->pool_lock);
 178         list_splice(&unmap_list, &pool->free_list);
 179         spin_unlock_irq(&pool->pool_lock);
 180 }
 181
 182 static int ib_fmr_cleanup_thread(void *pool_ptr)
 183 {
 184         struct ib_fmr_pool *pool = pool_ptr;
 185
 186         do {
 187                 if (atomic_read(&pool->flush_ser) - atomic_read(&pool->req_ser) < 0) {
 188                         ib_fmr_batch_release(pool);
 189
 190                         atomic_inc(&pool->flush_ser);
 191                         wake_up_interruptible(&pool->force_wait);
 192
 193                         if (pool->flush_function)
 194                                 pool->flush_function(pool, pool->flush_arg);
 195                 }
 196
 197                 set_current_state(TASK_INTERRUPTIBLE);
 198                 if (atomic_read(&pool->flush_ser) - atomic_read(&pool->req_ser) >= 0 &&
 199                     !kthread_should_stop())
 200                         schedule();
 201                 __set_current_state(TASK_RUNNING);
 202         } while (!kthread_should_stop());
 203
 204         return 0;
 205 }
 206
 207 /**
 208  * ib_create_fmr_pool - Create an FMR pool
 209  * @pd:Protection domain for FMRs
 210  * @params:FMR pool parameters
 211  *
 212  * Create a pool of FMRs.  Return value is pointer to new pool or
 213  * error code if creation failed.
 214  */
 215 struct ib_fmr_pool *ib_create_fmr_pool(struct ib_pd             *pd,
 216                                        struct ib_fmr_pool_param *params)
 217 {
 218         struct ib_device   *device;
 219         struct ib_fmr_pool *pool;
 220         int i;
 221         int ret;
 222         int max_remaps;
 223
 224         if (!params)
 225                 return ERR_PTR(-EINVAL);
 226
 227         device = pd->device;
 228         if (!device->alloc_fmr    || !device->dealloc_fmr  ||
 229             !device->map_phys_fmr || !device->unmap_fmr) {
 230                 pr_info(PFX "Device %s does not support FMRs\n", device->name);
 231                 return ERR_PTR(-ENOSYS);
 232         }
 233
 234         if (!device->attrs.max_map_per_fmr)
 235                 max_remaps = IB_FMR_MAX_REMAPS;
 236         else
 237                 max_remaps = device->attrs.max_map_per_fmr;
 238
 239         pool = kmalloc(sizeof *pool, GFP_KERNEL);
 240         if (!pool)
 241                 return ERR_PTR(-ENOMEM);
 242
 243         pool->cache_bucket   = NULL;
 244         pool->flush_function = params->flush_function;
 245         pool->flush_arg      = params->flush_arg;
 246
 247         INIT_LIST_HEAD(&pool->free_list);
 248         INIT_LIST_HEAD(&pool->dirty_list);
 249
 250         if (params->cache) {
 251                 pool->cache_bucket =
 252                         kmalloc(IB_FMR_HASH_SIZE * sizeof *pool->cache_bucket,
 253                                 GFP_KERNEL);
 254                 if (!pool->cache_bucket) {
 255                         pr_warn(PFX "Failed to allocate cache in pool\n");
 256                         ret = -ENOMEM;
 257                         goto out_free_pool;
 258                 }
 259
 260                 for (i = 0; i < IB_FMR_HASH_SIZE; ++i)
 261                         INIT_HLIST_HEAD(pool->cache_bucket + i);
 262         }
 263
 264         pool->pool_size       = 0;
 265         pool->max_pages       = params->max_pages_per_fmr;
 266         pool->max_remaps      = max_remaps;
 267         pool->dirty_watermark = params->dirty_watermark;
 268         pool->dirty_len       = 0;
 269         spin_lock_init(&pool->pool_lock);
 270         atomic_set(&pool->req_ser,   0);
 271         atomic_set(&pool->flush_ser, 0);
 272         init_waitqueue_head(&pool->force_wait);
 273
 274         pool->thread = kthread_run(ib_fmr_cleanup_thread,
 275                                    pool,
 276                                    "ib_fmr(%s)",
 277                                    device->name);
 278         if (IS_ERR(pool->thread)) {
 279                 pr_warn(PFX "couldn't start cleanup thread\n");
 280                 ret = PTR_ERR(pool->thread);
 281                 goto out_free_pool;
 282         }
 283
 284         {
 285                 struct ib_pool_fmr *fmr;
 286                 struct ib_fmr_attr fmr_attr = {
 287                         .max_pages  = params->max_pages_per_fmr,
 288                         .max_maps   = pool->max_remaps,
 289                         .page_shift = params->page_shift
 290                 };
 291                 int bytes_per_fmr = sizeof *fmr;
 292
 293                 if (pool->cache_bucket)
 294                         bytes_per_fmr += params->max_pages_per_fmr * sizeof (u64);
 295
 296                 for (i = 0; i < params->pool_size; ++i) {
 297                         fmr = kmalloc(bytes_per_fmr, GFP_KERNEL);
 298                         if (!fmr)
 299                                 goto out_fail;
 300
 301                         fmr->pool             = pool;
 302                         fmr->remap_count      = 0;
 303                         fmr->ref_count        = 0;
 304                         INIT_HLIST_NODE(&fmr->cache_node);
 305
 306                         fmr->fmr = ib_alloc_fmr(pd, params->access, &fmr_attr);
 307                         if (IS_ERR(fmr->fmr)) {
 308                                 pr_warn(PFX "fmr_create failed for FMR %d\n",
 309                                         i);
 310                                 kfree(fmr);
 311                                 goto out_fail;
 312                         }
 313
 314                         list_add_tail(&fmr->list, &pool->free_list);
 315                         ++pool->pool_size;
 316                 }
 317         }
 318
 319         return pool;
 320
 321  out_free_pool:
 322         kfree(pool->cache_bucket);
 323         kfree(pool);
 324
 325         return ERR_PTR(ret);
 326
 327  out_fail:
 328         ib_destroy_fmr_pool(pool);
 329
 330         return ERR_PTR(-ENOMEM);
 331 }
 332 EXPORT_SYMBOL(ib_create_fmr_pool);
 333
 334 /**
 335  * ib_destroy_fmr_pool - Free FMR pool
 336  * @pool:FMR pool to free
 337  *
 338  * Destroy an FMR pool and free all associated resources.
 339  */
 340 void ib_destroy_fmr_pool(struct ib_fmr_pool *pool)
 341 {
 342         struct ib_pool_fmr *fmr;
 343         struct ib_pool_fmr *tmp;
 344         LIST_HEAD(fmr_list);
 345         int                 i;
 346
 347         kthread_stop(pool->thread);
 348         ib_fmr_batch_release(pool);
 349
 350         i = 0;
 351         list_for_each_entry_safe(fmr, tmp, &pool->free_list, list) {
 352                 if (fmr->remap_count) {
 353                         INIT_LIST_HEAD(&fmr_list);
 354                         list_add_tail(&fmr->fmr->list, &fmr_list);
 355                         ib_unmap_fmr(&fmr_list);
 356                 }
 357                 ib_dealloc_fmr(fmr->fmr);
 358                 list_del(&fmr->list);
 359                 kfree(fmr);
 360                 ++i;
 361         }
 362
 363         if (i < pool->pool_size)
 364                 pr_warn(PFX "pool still has %d regions registered\n",
 365                         pool->pool_size - i);
 366
 367         kfree(pool->cache_bucket);
 368         kfree(pool);
 369 }
 370 EXPORT_SYMBOL(ib_destroy_fmr_pool);
 371
 372 /**
 373  * ib_flush_fmr_pool - Invalidate all unmapped FMRs
 374  * @pool:FMR pool to flush
 375  *
 376  * Ensure that all unmapped FMRs are fully invalidated.
 377  */
 378 int ib_flush_fmr_pool(struct ib_fmr_pool *pool)
 379 {
 380         int serial;
 381         struct ib_pool_fmr *fmr, *next;
 382
 383         /*
 384          * The free_list holds FMRs that may have been used
 385          * but have not been remapped enough times to be dirty.
 386          * Put them on the dirty list now so that the cleanup
 387          * thread will reap them too.
 388          */
 389         spin_lock_irq(&pool->pool_lock);
 390         list_for_each_entry_safe(fmr, next, &pool->free_list, list) {
 391                 if (fmr->remap_count > 0)
 392                         list_move(&fmr->list, &pool->dirty_list);
 393         }
 394         spin_unlock_irq(&pool->pool_lock);
 395
 396         serial = atomic_inc_return(&pool->req_ser);
 397         wake_up_process(pool->thread);
 398
 399         if (wait_event_interruptible(pool->force_wait,
 400                                      atomic_read(&pool->flush_ser) - serial >= 0))
 401                 return -EINTR;
 402
 403         return 0;
 404 }
 405 EXPORT_SYMBOL(ib_flush_fmr_pool);
 406
 407 /**
 408  * ib_fmr_pool_map_phys -
 409  * @pool:FMR pool to allocate FMR from
 410  * @page_list:List of pages to map
 411  * @list_len:Number of pages in @page_list
 412  * @io_virtual_address:I/O virtual address for new FMR
 413  *
 414  * Map an FMR from an FMR pool.
 415  */
 416 struct ib_pool_fmr *ib_fmr_pool_map_phys(struct ib_fmr_pool *pool_handle,
 417                                          u64                *page_list,
 418                                          int                 list_len,
 419                                          u64                 io_virtual_address)
 420 {
 421         struct ib_fmr_pool *pool = pool_handle;
 422         struct ib_pool_fmr *fmr;
 423         unsigned long       flags;
 424         int                 result;
 425
 426         if (list_len < 1 || list_len > pool->max_pages)
 427                 return ERR_PTR(-EINVAL);
 428
 429         spin_lock_irqsave(&pool->pool_lock, flags);
 430         fmr = ib_fmr_cache_lookup(pool,
 431                                   page_list,
 432                                   list_len,
 433                                   io_virtual_address);
 434         if (fmr) {
 435                 /* found in cache */
 436                 ++fmr->ref_count;
 437                 if (fmr->ref_count == 1) {
 438                         list_del(&fmr->list);
 439                 }
 440
 441                 spin_unlock_irqrestore(&pool->pool_lock, flags);
 442
 443                 return fmr;
 444         }
 445
 446         if (list_empty(&pool->free_list)) {
 447                 spin_unlock_irqrestore(&pool->pool_lock, flags);
 448                 return ERR_PTR(-EAGAIN);
 449         }
 450
 451         fmr = list_entry(pool->free_list.next, struct ib_pool_fmr, list);
 452         list_del(&fmr->list);
 453         hlist_del_init(&fmr->cache_node);
 454         spin_unlock_irqrestore(&pool->pool_lock, flags);
 455
 456         result = ib_map_phys_fmr(fmr->fmr, page_list, list_len,
 457                                  io_virtual_address);
 458
 459         if (result) {
 460                 spin_lock_irqsave(&pool->pool_lock, flags);
 461                 list_add(&fmr->list, &pool->free_list);
 462                 spin_unlock_irqrestore(&pool->pool_lock, flags);
 463
 464                 pr_warn(PFX "fmr_map returns %d\n", result);
 465
 466                 return ERR_PTR(result);
 467         }
 468
 469         ++fmr->remap_count;
 470         fmr->ref_count = 1;
 471
 472         if (pool->cache_bucket) {
 473                 fmr->io_virtual_address = io_virtual_address;
 474                 fmr->page_list_len      = list_len;
 475                 memcpy(fmr->page_list, page_list, list_len * sizeof(*page_list));
 476
 477                 spin_lock_irqsave(&pool->pool_lock, flags);
 478                 hlist_add_head(&fmr->cache_node,
 479                                pool->cache_bucket + ib_fmr_hash(fmr->page_list[0]));
 480                 spin_unlock_irqrestore(&pool->pool_lock, flags);
 481         }
 482
 483         return fmr;
 484 }
 485 EXPORT_SYMBOL(ib_fmr_pool_map_phys);
 486
 487 /**
 488  * ib_fmr_pool_unmap - Unmap FMR
 489  * @fmr:FMR to unmap
 490  *
 491  * Unmap an FMR.  The FMR mapping may remain valid until the FMR is
 492  * reused (or until ib_flush_fmr_pool() is called).
 493  */
 494 int ib_fmr_pool_unmap(struct ib_pool_fmr *fmr)
 495 {
 496         struct ib_fmr_pool *pool;
 497         unsigned long flags;
 498
 499         pool = fmr->pool;
 500
 501         spin_lock_irqsave(&pool->pool_lock, flags);
 502
 503         --fmr->ref_count;
 504         if (!fmr->ref_count) {
 505                 if (fmr->remap_count < pool->max_remaps) {
 506                         list_add_tail(&fmr->list, &pool->free_list);
 507                 } else {
 508                         list_add_tail(&fmr->list, &pool->dirty_list);
 509                         if (++pool->dirty_len >= pool->dirty_watermark) {
 510                                 atomic_inc(&pool->req_ser);
 511                                 wake_up_process(pool->thread);
 512                         }
 513                 }
 514         }
 515
 516 #ifdef DEBUG
 517         if (fmr->ref_count < 0)
 518                 pr_warn(PFX "FMR %p has ref count %d < 0\n",
 519                         fmr, fmr->ref_count);
 520 #endif
 521
 522         spin_unlock_irqrestore(&pool->pool_lock, flags);
 523
 524         return 0;
 525 }
 526 EXPORT_SYMBOL(ib_fmr_pool_unmap);