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