net/rds/ib_rdma.c

   1 /*
   2  * Copyright (c) 2006 Oracle.  All rights reserved.
   3  *
   4  * This software is available to you under a choice of one of two
   5  * licenses.  You may choose to be licensed under the terms of the GNU
   6  * General Public License (GPL) Version 2, available from the file
   7  * COPYING in the main directory of this source tree, or the
   8  * OpenIB.org BSD license below:
   9  *
  10  *     Redistribution and use in source and binary forms, with or
  11  *     without modification, are permitted provided that the following
  12  *     conditions are met:
  13  *
  14  *      - Redistributions of source code must retain the above
  15  *        copyright notice, this list of conditions and the following
  16  *        disclaimer.
  17  *
  18  *      - Redistributions in binary form must reproduce the above
  19  *        copyright notice, this list of conditions and the following
  20  *        disclaimer in the documentation and/or other materials
  21  *        provided with the distribution.
  22  *
  23  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  24  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  25  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  26  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  27  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  28  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  29  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  30  * SOFTWARE.
  31  *
  32  */
  33 #include <linux/kernel.h>
  34 #include <linux/slab.h>
  35 #include <linux/rculist.h>
  36
  37 #include "rds.h"
  38 #include "ib.h"
  39
  40
  41 /*
  42  * This is stored as mr->r_trans_private.
  43  */
  44 struct rds_ib_mr {
  45         struct rds_ib_device    *device;
  46         struct rds_ib_mr_pool   *pool;
  47         struct ib_fmr           *fmr;
  48         struct list_head        list;
  49         unsigned int            remap_count;
  50
  51         struct scatterlist      *sg;
  52         unsigned int            sg_len;
  53         u64                     *dma;
  54         int                     sg_dma_len;
  55 };
  56
  57 /*
  58  * Our own little FMR pool
  59  */
  60 struct rds_ib_mr_pool {
  61         struct mutex            flush_lock;             /* serialize fmr invalidate */
  62         struct work_struct      flush_worker;           /* flush worker */
  63
  64         spinlock_t              list_lock;              /* protect variables below */
  65         atomic_t                item_count;             /* total # of MRs */
  66         atomic_t                dirty_count;            /* # dirty of MRs */
  67         struct list_head        drop_list;              /* MRs that have reached their max_maps limit */
  68         struct list_head        free_list;              /* unused MRs */
  69         struct list_head        clean_list;             /* unused & unamapped MRs */
  70         atomic_t                free_pinned;            /* memory pinned by free MRs */
  71         unsigned long           max_items;
  72         unsigned long           max_items_soft;
  73         unsigned long           max_free_pinned;
  74         struct ib_fmr_attr      fmr_attr;
  75 };
  76
  77 static int rds_ib_flush_mr_pool(struct rds_ib_mr_pool *pool, int free_all);
  78 static void rds_ib_teardown_mr(struct rds_ib_mr *ibmr);
  79 static void rds_ib_mr_pool_flush_worker(struct work_struct *work);
  80
  81 static struct rds_ib_device *rds_ib_get_device(__be32 ipaddr)
  82 {
  83         struct rds_ib_device *rds_ibdev;
  84         struct rds_ib_ipaddr *i_ipaddr;
  85
  86         list_for_each_entry(rds_ibdev, &rds_ib_devices, list) {
  87                 rcu_read_lock();
  88                 list_for_each_entry_rcu(i_ipaddr, &rds_ibdev->ipaddr_list, list) {
  89                         if (i_ipaddr->ipaddr == ipaddr) {
  90                                 rcu_read_unlock();
  91                                 return rds_ibdev;
  92                         }
  93                 }
  94                 rcu_read_unlock();
  95         }
  96
  97         return NULL;
  98 }
  99
 100 static int rds_ib_add_ipaddr(struct rds_ib_device *rds_ibdev, __be32 ipaddr)
 101 {
 102         struct rds_ib_ipaddr *i_ipaddr;
 103
 104         i_ipaddr = kmalloc(sizeof *i_ipaddr, GFP_KERNEL);
 105         if (!i_ipaddr)
 106                 return -ENOMEM;
 107
 108         i_ipaddr->ipaddr = ipaddr;
 109
 110         spin_lock_irq(&rds_ibdev->spinlock);
 111         list_add_tail_rcu(&i_ipaddr->list, &rds_ibdev->ipaddr_list);
 112         spin_unlock_irq(&rds_ibdev->spinlock);
 113
 114         return 0;
 115 }
 116
 117 static void rds_ib_remove_ipaddr(struct rds_ib_device *rds_ibdev, __be32 ipaddr)
 118 {
 119         struct rds_ib_ipaddr *i_ipaddr;
 120         struct rds_ib_ipaddr *to_free = NULL;
 121
 122
 123         spin_lock_irq(&rds_ibdev->spinlock);
 124         list_for_each_entry_rcu(i_ipaddr, &rds_ibdev->ipaddr_list, list) {
 125                 if (i_ipaddr->ipaddr == ipaddr) {
 126                         list_del_rcu(&i_ipaddr->list);
 127                         to_free = i_ipaddr;
 128                         break;
 129                 }
 130         }
 131         spin_unlock_irq(&rds_ibdev->spinlock);
 132
 133         if (to_free) {
 134                 synchronize_rcu();
 135                 kfree(to_free);
 136         }
 137 }
 138
 139 int rds_ib_update_ipaddr(struct rds_ib_device *rds_ibdev, __be32 ipaddr)
 140 {
 141         struct rds_ib_device *rds_ibdev_old;
 142
 143         rds_ibdev_old = rds_ib_get_device(ipaddr);
 144         if (rds_ibdev_old)
 145                 rds_ib_remove_ipaddr(rds_ibdev_old, ipaddr);
 146
 147         return rds_ib_add_ipaddr(rds_ibdev, ipaddr);
 148 }
 149
 150 void rds_ib_add_conn(struct rds_ib_device *rds_ibdev, struct rds_connection *conn)
 151 {
 152         struct rds_ib_connection *ic = conn->c_transport_data;
 153
 154         /* conn was previously on the nodev_conns_list */
 155         spin_lock_irq(&ib_nodev_conns_lock);
 156         BUG_ON(list_empty(&ib_nodev_conns));
 157         BUG_ON(list_empty(&ic->ib_node));
 158         list_del(&ic->ib_node);
 159
 160         spin_lock_irq(&rds_ibdev->spinlock);
 161         list_add_tail(&ic->ib_node, &rds_ibdev->conn_list);
 162         spin_unlock_irq(&rds_ibdev->spinlock);
 163         spin_unlock_irq(&ib_nodev_conns_lock);
 164
 165         ic->rds_ibdev = rds_ibdev;
 166 }
 167
 168 void rds_ib_remove_conn(struct rds_ib_device *rds_ibdev, struct rds_connection *conn)
 169 {
 170         struct rds_ib_connection *ic = conn->c_transport_data;
 171
 172         /* place conn on nodev_conns_list */
 173         spin_lock(&ib_nodev_conns_lock);
 174
 175         spin_lock_irq(&rds_ibdev->spinlock);
 176         BUG_ON(list_empty(&ic->ib_node));
 177         list_del(&ic->ib_node);
 178         spin_unlock_irq(&rds_ibdev->spinlock);
 179
 180         list_add_tail(&ic->ib_node, &ib_nodev_conns);
 181
 182         spin_unlock(&ib_nodev_conns_lock);
 183
 184         ic->rds_ibdev = NULL;
 185 }
 186
 187 void __rds_ib_destroy_conns(struct list_head *list, spinlock_t *list_lock)
 188 {
 189         struct rds_ib_connection *ic, *_ic;
 190         LIST_HEAD(tmp_list);
 191
 192         /* avoid calling conn_destroy with irqs off */
 193         spin_lock_irq(list_lock);
 194         list_splice(list, &tmp_list);
 195         INIT_LIST_HEAD(list);
 196         spin_unlock_irq(list_lock);
 197
 198         list_for_each_entry_safe(ic, _ic, &tmp_list, ib_node)
 199                 rds_conn_destroy(ic->conn);
 200 }
 201
 202 struct rds_ib_mr_pool *rds_ib_create_mr_pool(struct rds_ib_device *rds_ibdev)
 203 {
 204         struct rds_ib_mr_pool *pool;
 205
 206         pool = kzalloc(sizeof(*pool), GFP_KERNEL);
 207         if (!pool)
 208                 return ERR_PTR(-ENOMEM);
 209
 210         INIT_LIST_HEAD(&pool->free_list);
 211         INIT_LIST_HEAD(&pool->drop_list);
 212         INIT_LIST_HEAD(&pool->clean_list);
 213         mutex_init(&pool->flush_lock);
 214         spin_lock_init(&pool->list_lock);
 215         INIT_WORK(&pool->flush_worker, rds_ib_mr_pool_flush_worker);
 216
 217         pool->fmr_attr.max_pages = fmr_message_size;
 218         pool->fmr_attr.max_maps = rds_ibdev->fmr_max_remaps;
 219         pool->fmr_attr.page_shift = PAGE_SHIFT;
 220         pool->max_free_pinned = rds_ibdev->max_fmrs * fmr_message_size / 4;
 221
 222         /* We never allow more than max_items MRs to be allocated.
 223          * When we exceed more than max_items_soft, we start freeing
 224          * items more aggressively.
 225          * Make sure that max_items > max_items_soft > max_items / 2
 226          */
 227         pool->max_items_soft = rds_ibdev->max_fmrs * 3 / 4;
 228         pool->max_items = rds_ibdev->max_fmrs;
 229
 230         return pool;
 231 }
 232
 233 void rds_ib_get_mr_info(struct rds_ib_device *rds_ibdev, struct rds_info_rdma_connection *iinfo)
 234 {
 235         struct rds_ib_mr_pool *pool = rds_ibdev->mr_pool;
 236
 237         iinfo->rdma_mr_max = pool->max_items;
 238         iinfo->rdma_mr_size = pool->fmr_attr.max_pages;
 239 }
 240
 241 void rds_ib_destroy_mr_pool(struct rds_ib_mr_pool *pool)
 242 {
 243         flush_workqueue(rds_wq);
 244         rds_ib_flush_mr_pool(pool, 1);
 245         WARN_ON(atomic_read(&pool->item_count));
 246         WARN_ON(atomic_read(&pool->free_pinned));
 247         kfree(pool);
 248 }
 249
 250 static inline struct rds_ib_mr *rds_ib_reuse_fmr(struct rds_ib_mr_pool *pool)
 251 {
 252         struct rds_ib_mr *ibmr = NULL;
 253         unsigned long flags;
 254
 255         spin_lock_irqsave(&pool->list_lock, flags);
 256         if (!list_empty(&pool->clean_list)) {
 257                 ibmr = list_entry(pool->clean_list.next, struct rds_ib_mr, list);
 258                 list_del_init(&ibmr->list);
 259         }
 260         spin_unlock_irqrestore(&pool->list_lock, flags);
 261
 262         return ibmr;
 263 }
 264
 265 static struct rds_ib_mr *rds_ib_alloc_fmr(struct rds_ib_device *rds_ibdev)
 266 {
 267         struct rds_ib_mr_pool *pool = rds_ibdev->mr_pool;
 268         struct rds_ib_mr *ibmr = NULL;
 269         int err = 0, iter = 0;
 270
 271         while (1) {
 272                 ibmr = rds_ib_reuse_fmr(pool);
 273                 if (ibmr)
 274                         return ibmr;
 275
 276                 /* No clean MRs - now we have the choice of either
 277                  * allocating a fresh MR up to the limit imposed by the
 278                  * driver, or flush any dirty unused MRs.
 279                  * We try to avoid stalling in the send path if possible,
 280                  * so we allocate as long as we're allowed to.
 281                  *
 282                  * We're fussy with enforcing the FMR limit, though. If the driver
 283                  * tells us we can't use more than N fmrs, we shouldn't start
 284                  * arguing with it */
 285                 if (atomic_inc_return(&pool->item_count) <= pool->max_items)
 286                         break;
 287
 288                 atomic_dec(&pool->item_count);
 289
 290                 if (++iter > 2) {
 291                         rds_ib_stats_inc(s_ib_rdma_mr_pool_depleted);
 292                         return ERR_PTR(-EAGAIN);
 293                 }
 294
 295                 /* We do have some empty MRs. Flush them out. */
 296                 rds_ib_stats_inc(s_ib_rdma_mr_pool_wait);
 297                 rds_ib_flush_mr_pool(pool, 0);
 298         }
 299
 300         ibmr = kzalloc_node(sizeof(*ibmr), GFP_KERNEL, rdsibdev_to_node(rds_ibdev));
 301         if (!ibmr) {
 302                 err = -ENOMEM;
 303                 goto out_no_cigar;
 304         }
 305
 306         memset(ibmr, 0, sizeof(*ibmr));
 307
 308         ibmr->fmr = ib_alloc_fmr(rds_ibdev->pd,
 309                         (IB_ACCESS_LOCAL_WRITE |
 310                          IB_ACCESS_REMOTE_READ |
 311                          IB_ACCESS_REMOTE_WRITE|
 312                          IB_ACCESS_REMOTE_ATOMIC),
 313
 314                         &pool->fmr_attr);
 315         if (IS_ERR(ibmr->fmr)) {
 316                 err = PTR_ERR(ibmr->fmr);
 317                 ibmr->fmr = NULL;
 318                 printk(KERN_WARNING "RDS/IB: ib_alloc_fmr failed (err=%d)\n", err);
 319                 goto out_no_cigar;
 320         }
 321
 322         rds_ib_stats_inc(s_ib_rdma_mr_alloc);
 323         return ibmr;
 324
 325 out_no_cigar:
 326         if (ibmr) {
 327                 if (ibmr->fmr)
 328                         ib_dealloc_fmr(ibmr->fmr);
 329                 kfree(ibmr);
 330         }
 331         atomic_dec(&pool->item_count);
 332         return ERR_PTR(err);
 333 }
 334
 335 static int rds_ib_map_fmr(struct rds_ib_device *rds_ibdev, struct rds_ib_mr *ibmr,
 336                struct scatterlist *sg, unsigned int nents)
 337 {
 338         struct ib_device *dev = rds_ibdev->dev;
 339         struct scatterlist *scat = sg;
 340         u64 io_addr = 0;
 341         u64 *dma_pages;
 342         u32 len;
 343         int page_cnt, sg_dma_len;
 344         int i, j;
 345         int ret;
 346
 347         sg_dma_len = ib_dma_map_sg(dev, sg, nents,
 348                                  DMA_BIDIRECTIONAL);
 349         if (unlikely(!sg_dma_len)) {
 350                 printk(KERN_WARNING "RDS/IB: dma_map_sg failed!\n");
 351                 return -EBUSY;
 352         }
 353
 354         len = 0;
 355         page_cnt = 0;
 356
 357         for (i = 0; i < sg_dma_len; ++i) {
 358                 unsigned int dma_len = ib_sg_dma_len(dev, &scat[i]);
 359                 u64 dma_addr = ib_sg_dma_address(dev, &scat[i]);
 360
 361                 if (dma_addr & ~PAGE_MASK) {
 362                         if (i > 0)
 363                                 return -EINVAL;
 364                         else
 365                                 ++page_cnt;
 366                 }
 367                 if ((dma_addr + dma_len) & ~PAGE_MASK) {
 368                         if (i < sg_dma_len - 1)
 369                                 return -EINVAL;
 370                         else
 371                                 ++page_cnt;
 372                 }
 373
 374                 len += dma_len;
 375         }
 376
 377         page_cnt += len >> PAGE_SHIFT;
 378         if (page_cnt > fmr_message_size)
 379                 return -EINVAL;
 380
 381         dma_pages = kmalloc_node(sizeof(u64) * page_cnt, GFP_ATOMIC,
 382                                  rdsibdev_to_node(rds_ibdev));
 383         if (!dma_pages)
 384                 return -ENOMEM;
 385
 386         page_cnt = 0;
 387         for (i = 0; i < sg_dma_len; ++i) {
 388                 unsigned int dma_len = ib_sg_dma_len(dev, &scat[i]);
 389                 u64 dma_addr = ib_sg_dma_address(dev, &scat[i]);
 390
 391                 for (j = 0; j < dma_len; j += PAGE_SIZE)
 392                         dma_pages[page_cnt++] =
 393                                 (dma_addr & PAGE_MASK) + j;
 394         }
 395
 396         ret = ib_map_phys_fmr(ibmr->fmr,
 397                                    dma_pages, page_cnt, io_addr);
 398         if (ret)
 399                 goto out;
 400
 401         /* Success - we successfully remapped the MR, so we can
 402          * safely tear down the old mapping. */
 403         rds_ib_teardown_mr(ibmr);
 404
 405         ibmr->sg = scat;
 406         ibmr->sg_len = nents;
 407         ibmr->sg_dma_len = sg_dma_len;
 408         ibmr->remap_count++;
 409
 410         rds_ib_stats_inc(s_ib_rdma_mr_used);
 411         ret = 0;
 412
 413 out:
 414         kfree(dma_pages);
 415
 416         return ret;
 417 }
 418
 419 void rds_ib_sync_mr(void *trans_private, int direction)
 420 {
 421         struct rds_ib_mr *ibmr = trans_private;
 422         struct rds_ib_device *rds_ibdev = ibmr->device;
 423
 424         switch (direction) {
 425         case DMA_FROM_DEVICE:
 426                 ib_dma_sync_sg_for_cpu(rds_ibdev->dev, ibmr->sg,
 427                         ibmr->sg_dma_len, DMA_BIDIRECTIONAL);
 428                 break;
 429         case DMA_TO_DEVICE:
 430                 ib_dma_sync_sg_for_device(rds_ibdev->dev, ibmr->sg,
 431                         ibmr->sg_dma_len, DMA_BIDIRECTIONAL);
 432                 break;
 433         }
 434 }
 435
 436 static void __rds_ib_teardown_mr(struct rds_ib_mr *ibmr)
 437 {
 438         struct rds_ib_device *rds_ibdev = ibmr->device;
 439
 440         if (ibmr->sg_dma_len) {
 441                 ib_dma_unmap_sg(rds_ibdev->dev,
 442                                 ibmr->sg, ibmr->sg_len,
 443                                 DMA_BIDIRECTIONAL);
 444                 ibmr->sg_dma_len = 0;
 445         }
 446
 447         /* Release the s/g list */
 448         if (ibmr->sg_len) {
 449                 unsigned int i;
 450
 451                 for (i = 0; i < ibmr->sg_len; ++i) {
 452                         struct page *page = sg_page(&ibmr->sg[i]);
 453
 454                         /* FIXME we need a way to tell a r/w MR
 455                          * from a r/o MR */
 456                         BUG_ON(irqs_disabled());
 457                         set_page_dirty(page);
 458                         put_page(page);
 459                 }
 460                 kfree(ibmr->sg);
 461
 462                 ibmr->sg = NULL;
 463                 ibmr->sg_len = 0;
 464         }
 465 }
 466
 467 static void rds_ib_teardown_mr(struct rds_ib_mr *ibmr)
 468 {
 469         unsigned int pinned = ibmr->sg_len;
 470
 471         __rds_ib_teardown_mr(ibmr);
 472         if (pinned) {
 473                 struct rds_ib_device *rds_ibdev = ibmr->device;
 474                 struct rds_ib_mr_pool *pool = rds_ibdev->mr_pool;
 475
 476                 atomic_sub(pinned, &pool->free_pinned);
 477         }
 478 }
 479
 480 static inline unsigned int rds_ib_flush_goal(struct rds_ib_mr_pool *pool, int free_all)
 481 {
 482         unsigned int item_count;
 483
 484         item_count = atomic_read(&pool->item_count);
 485         if (free_all)
 486                 return item_count;
 487
 488         return 0;
 489 }
 490
 491 /*
 492  * Flush our pool of MRs.
 493  * At a minimum, all currently unused MRs are unmapped.
 494  * If the number of MRs allocated exceeds the limit, we also try
 495  * to free as many MRs as needed to get back to this limit.
 496  */
 497 static int rds_ib_flush_mr_pool(struct rds_ib_mr_pool *pool, int free_all)
 498 {
 499         struct rds_ib_mr *ibmr, *next;
 500         LIST_HEAD(unmap_list);
 501         LIST_HEAD(fmr_list);
 502         unsigned long unpinned = 0;
 503         unsigned long flags;
 504         unsigned int nfreed = 0, ncleaned = 0, free_goal;
 505         int ret = 0;
 506
 507         rds_ib_stats_inc(s_ib_rdma_mr_pool_flush);
 508
 509         mutex_lock(&pool->flush_lock);
 510
 511         spin_lock_irqsave(&pool->list_lock, flags);
 512         /* Get the list of all MRs to be dropped. Ordering matters -
 513          * we want to put drop_list ahead of free_list. */
 514         list_splice_init(&pool->free_list, &unmap_list);
 515         list_splice_init(&pool->drop_list, &unmap_list);
 516         if (free_all)
 517                 list_splice_init(&pool->clean_list, &unmap_list);
 518         spin_unlock_irqrestore(&pool->list_lock, flags);
 519
 520         free_goal = rds_ib_flush_goal(pool, free_all);
 521
 522         if (list_empty(&unmap_list))
 523                 goto out;
 524
 525         /* String all ib_mr's onto one list and hand them to ib_unmap_fmr */
 526         list_for_each_entry(ibmr, &unmap_list, list)
 527                 list_add(&ibmr->fmr->list, &fmr_list);
 528         ret = ib_unmap_fmr(&fmr_list);
 529         if (ret)
 530                 printk(KERN_WARNING "RDS/IB: ib_unmap_fmr failed (err=%d)\n", ret);
 531
 532         /* Now we can destroy the DMA mapping and unpin any pages */
 533         list_for_each_entry_safe(ibmr, next, &unmap_list, list) {
 534                 unpinned += ibmr->sg_len;
 535                 __rds_ib_teardown_mr(ibmr);
 536                 if (nfreed < free_goal || ibmr->remap_count >= pool->fmr_attr.max_maps) {
 537                         rds_ib_stats_inc(s_ib_rdma_mr_free);
 538                         list_del(&ibmr->list);
 539                         ib_dealloc_fmr(ibmr->fmr);
 540                         kfree(ibmr);
 541                         nfreed++;
 542                 }
 543                 ncleaned++;
 544         }
 545
 546         spin_lock_irqsave(&pool->list_lock, flags);
 547         list_splice(&unmap_list, &pool->clean_list);
 548         spin_unlock_irqrestore(&pool->list_lock, flags);
 549
 550         atomic_sub(unpinned, &pool->free_pinned);
 551         atomic_sub(ncleaned, &pool->dirty_count);
 552         atomic_sub(nfreed, &pool->item_count);
 553
 554 out:
 555         mutex_unlock(&pool->flush_lock);
 556         return ret;
 557 }
 558
 559 static void rds_ib_mr_pool_flush_worker(struct work_struct *work)
 560 {
 561         struct rds_ib_mr_pool *pool = container_of(work, struct rds_ib_mr_pool, flush_worker);
 562
 563         rds_ib_flush_mr_pool(pool, 0);
 564 }
 565
 566 void rds_ib_free_mr(void *trans_private, int invalidate)
 567 {
 568         struct rds_ib_mr *ibmr = trans_private;
 569         struct rds_ib_device *rds_ibdev = ibmr->device;
 570         struct rds_ib_mr_pool *pool = rds_ibdev->mr_pool;
 571         unsigned long flags;
 572
 573         rdsdebug("RDS/IB: free_mr nents %u\n", ibmr->sg_len);
 574
 575         /* Return it to the pool's free list */
 576         spin_lock_irqsave(&pool->list_lock, flags);
 577         if (ibmr->remap_count >= pool->fmr_attr.max_maps)
 578                 list_add(&ibmr->list, &pool->drop_list);
 579         else
 580                 list_add(&ibmr->list, &pool->free_list);
 581
 582         atomic_add(ibmr->sg_len, &pool->free_pinned);
 583         atomic_inc(&pool->dirty_count);
 584         spin_unlock_irqrestore(&pool->list_lock, flags);
 585
 586         /* If we've pinned too many pages, request a flush */
 587         if (atomic_read(&pool->free_pinned) >= pool->max_free_pinned ||
 588             atomic_read(&pool->dirty_count) >= pool->max_items / 10)
 589                 queue_work(rds_wq, &pool->flush_worker);
 590
 591         if (invalidate) {
 592                 if (likely(!in_interrupt())) {
 593                         rds_ib_flush_mr_pool(pool, 0);
 594                 } else {
 595                         /* We get here if the user created a MR marked
 596                          * as use_once and invalidate at the same time. */
 597                         queue_work(rds_wq, &pool->flush_worker);
 598                 }
 599         }
 600 }
 601
 602 void rds_ib_flush_mrs(void)
 603 {
 604         struct rds_ib_device *rds_ibdev;
 605
 606         list_for_each_entry(rds_ibdev, &rds_ib_devices, list) {
 607                 struct rds_ib_mr_pool *pool = rds_ibdev->mr_pool;
 608
 609                 if (pool)
 610                         rds_ib_flush_mr_pool(pool, 0);
 611         }
 612 }
 613
 614 void *rds_ib_get_mr(struct scatterlist *sg, unsigned long nents,
 615                     struct rds_sock *rs, u32 *key_ret)
 616 {
 617         struct rds_ib_device *rds_ibdev;
 618         struct rds_ib_mr *ibmr = NULL;
 619         int ret;
 620
 621         rds_ibdev = rds_ib_get_device(rs->rs_bound_addr);
 622         if (!rds_ibdev) {
 623                 ret = -ENODEV;
 624                 goto out;
 625         }
 626
 627         if (!rds_ibdev->mr_pool) {
 628                 ret = -ENODEV;
 629                 goto out;
 630         }
 631
 632         ibmr = rds_ib_alloc_fmr(rds_ibdev);
 633         if (IS_ERR(ibmr))
 634                 return ibmr;
 635
 636         ret = rds_ib_map_fmr(rds_ibdev, ibmr, sg, nents);
 637         if (ret == 0)
 638                 *key_ret = ibmr->fmr->rkey;
 639         else
 640                 printk(KERN_WARNING "RDS/IB: map_fmr failed (errno=%d)\n", ret);
 641
 642         ibmr->device = rds_ibdev;
 643
 644  out:
 645         if (ret) {
 646                 if (ibmr)
 647                         rds_ib_free_mr(ibmr, 0);
 648                 ibmr = ERR_PTR(ret);
 649         }
 650         return ibmr;
 651 }