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
  36 #include "rds.h"
  37 #include "rdma.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                 spin_lock_irq(&rds_ibdev->spinlock);
  88                 list_for_each_entry(i_ipaddr, &rds_ibdev->ipaddr_list, list) {
  89                         if (i_ipaddr->ipaddr == ipaddr) {
  90                                 spin_unlock_irq(&rds_ibdev->spinlock);
  91                                 return rds_ibdev;
  92                         }
  93                 }
  94                 spin_unlock_irq(&rds_ibdev->spinlock);
  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(&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, *next;
 120
 121         spin_lock_irq(&rds_ibdev->spinlock);
 122         list_for_each_entry_safe(i_ipaddr, next, &rds_ibdev->ipaddr_list, list) {
 123                 if (i_ipaddr->ipaddr == ipaddr) {
 124                         list_del(&i_ipaddr->list);
 125                         kfree(i_ipaddr);
 126                         break;
 127                 }
 128         }
 129         spin_unlock_irq(&rds_ibdev->spinlock);
 130 }
 131
 132 int rds_ib_update_ipaddr(struct rds_ib_device *rds_ibdev, __be32 ipaddr)
 133 {
 134         struct rds_ib_device *rds_ibdev_old;
 135
 136         rds_ibdev_old = rds_ib_get_device(ipaddr);
 137         if (rds_ibdev_old)
 138                 rds_ib_remove_ipaddr(rds_ibdev_old, ipaddr);
 139
 140         return rds_ib_add_ipaddr(rds_ibdev, ipaddr);
 141 }
 142
 143 void rds_ib_add_conn(struct rds_ib_device *rds_ibdev, struct rds_connection *conn)
 144 {
 145         struct rds_ib_connection *ic = conn->c_transport_data;
 146
 147         /* conn was previously on the nodev_conns_list */
 148         spin_lock_irq(&ib_nodev_conns_lock);
 149         BUG_ON(list_empty(&ib_nodev_conns));
 150         BUG_ON(list_empty(&ic->ib_node));
 151         list_del(&ic->ib_node);
 152
 153         spin_lock_irq(&rds_ibdev->spinlock);
 154         list_add_tail(&ic->ib_node, &rds_ibdev->conn_list);
 155         spin_unlock_irq(&rds_ibdev->spinlock);
 156         spin_unlock_irq(&ib_nodev_conns_lock);
 157
 158         ic->rds_ibdev = rds_ibdev;
 159 }
 160
 161 void rds_ib_remove_conn(struct rds_ib_device *rds_ibdev, struct rds_connection *conn)
 162 {
 163         struct rds_ib_connection *ic = conn->c_transport_data;
 164
 165         /* place conn on nodev_conns_list */
 166         spin_lock(&ib_nodev_conns_lock);
 167
 168         spin_lock_irq(&rds_ibdev->spinlock);
 169         BUG_ON(list_empty(&ic->ib_node));
 170         list_del(&ic->ib_node);
 171         spin_unlock_irq(&rds_ibdev->spinlock);
 172
 173         list_add_tail(&ic->ib_node, &ib_nodev_conns);
 174
 175         spin_unlock(&ib_nodev_conns_lock);
 176
 177         ic->rds_ibdev = NULL;
 178 }
 179
 180 void __rds_ib_destroy_conns(struct list_head *list, spinlock_t *list_lock)
 181 {
 182         struct rds_ib_connection *ic, *_ic;
 183         LIST_HEAD(tmp_list);
 184
 185         /* avoid calling conn_destroy with irqs off */
 186         spin_lock_irq(list_lock);
 187         list_splice(list, &tmp_list);
 188         INIT_LIST_HEAD(list);
 189         spin_unlock_irq(list_lock);
 190
 191         list_for_each_entry_safe(ic, _ic, &tmp_list, ib_node)
 192                 rds_conn_destroy(ic->conn);
 193 }
 194
 195 struct rds_ib_mr_pool *rds_ib_create_mr_pool(struct rds_ib_device *rds_ibdev)
 196 {
 197         struct rds_ib_mr_pool *pool;
 198
 199         pool = kzalloc(sizeof(*pool), GFP_KERNEL);
 200         if (!pool)
 201                 return ERR_PTR(-ENOMEM);
 202
 203         INIT_LIST_HEAD(&pool->free_list);
 204         INIT_LIST_HEAD(&pool->drop_list);
 205         INIT_LIST_HEAD(&pool->clean_list);
 206         mutex_init(&pool->flush_lock);
 207         spin_lock_init(&pool->list_lock);
 208         INIT_WORK(&pool->flush_worker, rds_ib_mr_pool_flush_worker);
 209
 210         pool->fmr_attr.max_pages = fmr_message_size;
 211         pool->fmr_attr.max_maps = rds_ibdev->fmr_max_remaps;
 212         pool->fmr_attr.page_shift = PAGE_SHIFT;
 213         pool->max_free_pinned = rds_ibdev->max_fmrs * fmr_message_size / 4;
 214
 215         /* We never allow more than max_items MRs to be allocated.
 216          * When we exceed more than max_items_soft, we start freeing
 217          * items more aggressively.
 218          * Make sure that max_items > max_items_soft > max_items / 2
 219          */
 220         pool->max_items_soft = rds_ibdev->max_fmrs * 3 / 4;
 221         pool->max_items = rds_ibdev->max_fmrs;
 222
 223         return pool;
 224 }
 225
 226 void rds_ib_get_mr_info(struct rds_ib_device *rds_ibdev, struct rds_info_rdma_connection *iinfo)
 227 {
 228         struct rds_ib_mr_pool *pool = rds_ibdev->mr_pool;
 229
 230         iinfo->rdma_mr_max = pool->max_items;
 231         iinfo->rdma_mr_size = pool->fmr_attr.max_pages;
 232 }
 233
 234 void rds_ib_destroy_mr_pool(struct rds_ib_mr_pool *pool)
 235 {
 236         flush_workqueue(rds_wq);
 237         rds_ib_flush_mr_pool(pool, 1);
 238         BUG_ON(atomic_read(&pool->item_count));
 239         BUG_ON(atomic_read(&pool->free_pinned));
 240         kfree(pool);
 241 }
 242
 243 static inline struct rds_ib_mr *rds_ib_reuse_fmr(struct rds_ib_mr_pool *pool)
 244 {
 245         struct rds_ib_mr *ibmr = NULL;
 246         unsigned long flags;
 247
 248         spin_lock_irqsave(&pool->list_lock, flags);
 249         if (!list_empty(&pool->clean_list)) {
 250                 ibmr = list_entry(pool->clean_list.next, struct rds_ib_mr, list);
 251                 list_del_init(&ibmr->list);
 252         }
 253         spin_unlock_irqrestore(&pool->list_lock, flags);
 254
 255         return ibmr;
 256 }
 257
 258 static struct rds_ib_mr *rds_ib_alloc_fmr(struct rds_ib_device *rds_ibdev)
 259 {
 260         struct rds_ib_mr_pool *pool = rds_ibdev->mr_pool;
 261         struct rds_ib_mr *ibmr = NULL;
 262         int err = 0, iter = 0;
 263
 264         while (1) {
 265                 ibmr = rds_ib_reuse_fmr(pool);
 266                 if (ibmr)
 267                         return ibmr;
 268
 269                 /* No clean MRs - now we have the choice of either
 270                  * allocating a fresh MR up to the limit imposed by the
 271                  * driver, or flush any dirty unused MRs.
 272                  * We try to avoid stalling in the send path if possible,
 273                  * so we allocate as long as we're allowed to.
 274                  *
 275                  * We're fussy with enforcing the FMR limit, though. If the driver
 276                  * tells us we can't use more than N fmrs, we shouldn't start
 277                  * arguing with it */
 278                 if (atomic_inc_return(&pool->item_count) <= pool->max_items)
 279                         break;
 280
 281                 atomic_dec(&pool->item_count);
 282
 283                 if (++iter > 2) {
 284                         rds_ib_stats_inc(s_ib_rdma_mr_pool_depleted);
 285                         return ERR_PTR(-EAGAIN);
 286                 }
 287
 288                 /* We do have some empty MRs. Flush them out. */
 289                 rds_ib_stats_inc(s_ib_rdma_mr_pool_wait);
 290                 rds_ib_flush_mr_pool(pool, 0);
 291         }
 292
 293         ibmr = kzalloc(sizeof(*ibmr), GFP_KERNEL);
 294         if (!ibmr) {
 295                 err = -ENOMEM;
 296                 goto out_no_cigar;
 297         }
 298
 299         ibmr->fmr = ib_alloc_fmr(rds_ibdev->pd,
 300                         (IB_ACCESS_LOCAL_WRITE |
 301                          IB_ACCESS_REMOTE_READ |
 302                          IB_ACCESS_REMOTE_WRITE),
 303                         &pool->fmr_attr);
 304         if (IS_ERR(ibmr->fmr)) {
 305                 err = PTR_ERR(ibmr->fmr);
 306                 ibmr->fmr = NULL;
 307                 printk(KERN_WARNING "RDS/IB: ib_alloc_fmr failed (err=%d)\n", err);
 308                 goto out_no_cigar;
 309         }
 310
 311         rds_ib_stats_inc(s_ib_rdma_mr_alloc);
 312         return ibmr;
 313
 314 out_no_cigar:
 315         if (ibmr) {
 316                 if (ibmr->fmr)
 317                         ib_dealloc_fmr(ibmr->fmr);
 318                 kfree(ibmr);
 319         }
 320         atomic_dec(&pool->item_count);
 321         return ERR_PTR(err);
 322 }
 323
 324 static int rds_ib_map_fmr(struct rds_ib_device *rds_ibdev, struct rds_ib_mr *ibmr,
 325                struct scatterlist *sg, unsigned int nents)
 326 {
 327         struct ib_device *dev = rds_ibdev->dev;
 328         struct scatterlist *scat = sg;
 329         u64 io_addr = 0;
 330         u64 *dma_pages;
 331         u32 len;
 332         int page_cnt, sg_dma_len;
 333         int i, j;
 334         int ret;
 335
 336         sg_dma_len = ib_dma_map_sg(dev, sg, nents,
 337                                  DMA_BIDIRECTIONAL);
 338         if (unlikely(!sg_dma_len)) {
 339                 printk(KERN_WARNING "RDS/IB: dma_map_sg failed!\n");
 340                 return -EBUSY;
 341         }
 342
 343         len = 0;
 344         page_cnt = 0;
 345
 346         for (i = 0; i < sg_dma_len; ++i) {
 347                 unsigned int dma_len = ib_sg_dma_len(dev, &scat[i]);
 348                 u64 dma_addr = ib_sg_dma_address(dev, &scat[i]);
 349
 350                 if (dma_addr & ~PAGE_MASK) {
 351                         if (i > 0)
 352                                 return -EINVAL;
 353                         else
 354                                 ++page_cnt;
 355                 }
 356                 if ((dma_addr + dma_len) & ~PAGE_MASK) {
 357                         if (i < sg_dma_len - 1)
 358                                 return -EINVAL;
 359                         else
 360                                 ++page_cnt;
 361                 }
 362
 363                 len += dma_len;
 364         }
 365
 366         page_cnt += len >> PAGE_SHIFT;
 367         if (page_cnt > fmr_message_size)
 368                 return -EINVAL;
 369
 370         dma_pages = kmalloc(sizeof(u64) * page_cnt, GFP_ATOMIC);
 371         if (!dma_pages)
 372                 return -ENOMEM;
 373
 374         page_cnt = 0;
 375         for (i = 0; i < sg_dma_len; ++i) {
 376                 unsigned int dma_len = ib_sg_dma_len(dev, &scat[i]);
 377                 u64 dma_addr = ib_sg_dma_address(dev, &scat[i]);
 378
 379                 for (j = 0; j < dma_len; j += PAGE_SIZE)
 380                         dma_pages[page_cnt++] =
 381                                 (dma_addr & PAGE_MASK) + j;
 382         }
 383
 384         ret = ib_map_phys_fmr(ibmr->fmr,
 385                                    dma_pages, page_cnt, io_addr);
 386         if (ret)
 387                 goto out;
 388
 389         /* Success - we successfully remapped the MR, so we can
 390          * safely tear down the old mapping. */
 391         rds_ib_teardown_mr(ibmr);
 392
 393         ibmr->sg = scat;
 394         ibmr->sg_len = nents;
 395         ibmr->sg_dma_len = sg_dma_len;
 396         ibmr->remap_count++;
 397
 398         rds_ib_stats_inc(s_ib_rdma_mr_used);
 399         ret = 0;
 400
 401 out:
 402         kfree(dma_pages);
 403
 404         return ret;
 405 }
 406
 407 void rds_ib_sync_mr(void *trans_private, int direction)
 408 {
 409         struct rds_ib_mr *ibmr = trans_private;
 410         struct rds_ib_device *rds_ibdev = ibmr->device;
 411
 412         switch (direction) {
 413         case DMA_FROM_DEVICE:
 414                 ib_dma_sync_sg_for_cpu(rds_ibdev->dev, ibmr->sg,
 415                         ibmr->sg_dma_len, DMA_BIDIRECTIONAL);
 416                 break;
 417         case DMA_TO_DEVICE:
 418                 ib_dma_sync_sg_for_device(rds_ibdev->dev, ibmr->sg,
 419                         ibmr->sg_dma_len, DMA_BIDIRECTIONAL);
 420                 break;
 421         }
 422 }
 423
 424 static void __rds_ib_teardown_mr(struct rds_ib_mr *ibmr)
 425 {
 426         struct rds_ib_device *rds_ibdev = ibmr->device;
 427
 428         if (ibmr->sg_dma_len) {
 429                 ib_dma_unmap_sg(rds_ibdev->dev,
 430                                 ibmr->sg, ibmr->sg_len,
 431                                 DMA_BIDIRECTIONAL);
 432                 ibmr->sg_dma_len = 0;
 433         }
 434
 435         /* Release the s/g list */
 436         if (ibmr->sg_len) {
 437                 unsigned int i;
 438
 439                 for (i = 0; i < ibmr->sg_len; ++i) {
 440                         struct page *page = sg_page(&ibmr->sg[i]);
 441
 442                         /* FIXME we need a way to tell a r/w MR
 443                          * from a r/o MR */
 444                         set_page_dirty(page);
 445                         put_page(page);
 446                 }
 447                 kfree(ibmr->sg);
 448
 449                 ibmr->sg = NULL;
 450                 ibmr->sg_len = 0;
 451         }
 452 }
 453
 454 static void rds_ib_teardown_mr(struct rds_ib_mr *ibmr)
 455 {
 456         unsigned int pinned = ibmr->sg_len;
 457
 458         __rds_ib_teardown_mr(ibmr);
 459         if (pinned) {
 460                 struct rds_ib_device *rds_ibdev = ibmr->device;
 461                 struct rds_ib_mr_pool *pool = rds_ibdev->mr_pool;
 462
 463                 atomic_sub(pinned, &pool->free_pinned);
 464         }
 465 }
 466
 467 static inline unsigned int rds_ib_flush_goal(struct rds_ib_mr_pool *pool, int free_all)
 468 {
 469         unsigned int item_count;
 470
 471         item_count = atomic_read(&pool->item_count);
 472         if (free_all)
 473                 return item_count;
 474
 475         return 0;
 476 }
 477
 478 /*
 479  * Flush our pool of MRs.
 480  * At a minimum, all currently unused MRs are unmapped.
 481  * If the number of MRs allocated exceeds the limit, we also try
 482  * to free as many MRs as needed to get back to this limit.
 483  */
 484 static int rds_ib_flush_mr_pool(struct rds_ib_mr_pool *pool, int free_all)
 485 {
 486         struct rds_ib_mr *ibmr, *next;
 487         LIST_HEAD(unmap_list);
 488         LIST_HEAD(fmr_list);
 489         unsigned long unpinned = 0;
 490         unsigned long flags;
 491         unsigned int nfreed = 0, ncleaned = 0, free_goal;
 492         int ret = 0;
 493
 494         rds_ib_stats_inc(s_ib_rdma_mr_pool_flush);
 495
 496         mutex_lock(&pool->flush_lock);
 497
 498         spin_lock_irqsave(&pool->list_lock, flags);
 499         /* Get the list of all MRs to be dropped. Ordering matters -
 500          * we want to put drop_list ahead of free_list. */
 501         list_splice_init(&pool->free_list, &unmap_list);
 502         list_splice_init(&pool->drop_list, &unmap_list);
 503         if (free_all)
 504                 list_splice_init(&pool->clean_list, &unmap_list);
 505         spin_unlock_irqrestore(&pool->list_lock, flags);
 506
 507         free_goal = rds_ib_flush_goal(pool, free_all);
 508
 509         if (list_empty(&unmap_list))
 510                 goto out;
 511
 512         /* String all ib_mr's onto one list and hand them to ib_unmap_fmr */
 513         list_for_each_entry(ibmr, &unmap_list, list)
 514                 list_add(&ibmr->fmr->list, &fmr_list);
 515         ret = ib_unmap_fmr(&fmr_list);
 516         if (ret)
 517                 printk(KERN_WARNING "RDS/IB: ib_unmap_fmr failed (err=%d)\n", ret);
 518
 519         /* Now we can destroy the DMA mapping and unpin any pages */
 520         list_for_each_entry_safe(ibmr, next, &unmap_list, list) {
 521                 unpinned += ibmr->sg_len;
 522                 __rds_ib_teardown_mr(ibmr);
 523                 if (nfreed < free_goal || ibmr->remap_count >= pool->fmr_attr.max_maps) {
 524                         rds_ib_stats_inc(s_ib_rdma_mr_free);
 525                         list_del(&ibmr->list);
 526                         ib_dealloc_fmr(ibmr->fmr);
 527                         kfree(ibmr);
 528                         nfreed++;
 529                 }
 530                 ncleaned++;
 531         }
 532
 533         spin_lock_irqsave(&pool->list_lock, flags);
 534         list_splice(&unmap_list, &pool->clean_list);
 535         spin_unlock_irqrestore(&pool->list_lock, flags);
 536
 537         atomic_sub(unpinned, &pool->free_pinned);
 538         atomic_sub(ncleaned, &pool->dirty_count);
 539         atomic_sub(nfreed, &pool->item_count);
 540
 541 out:
 542         mutex_unlock(&pool->flush_lock);
 543         return ret;
 544 }
 545
 546 static void rds_ib_mr_pool_flush_worker(struct work_struct *work)
 547 {
 548         struct rds_ib_mr_pool *pool = container_of(work, struct rds_ib_mr_pool, flush_worker);
 549
 550         rds_ib_flush_mr_pool(pool, 0);
 551 }
 552
 553 void rds_ib_free_mr(void *trans_private, int invalidate)
 554 {
 555         struct rds_ib_mr *ibmr = trans_private;
 556         struct rds_ib_device *rds_ibdev = ibmr->device;
 557         struct rds_ib_mr_pool *pool = rds_ibdev->mr_pool;
 558         unsigned long flags;
 559
 560         rdsdebug("RDS/IB: free_mr nents %u\n", ibmr->sg_len);
 561
 562         /* Return it to the pool's free list */
 563         spin_lock_irqsave(&pool->list_lock, flags);
 564         if (ibmr->remap_count >= pool->fmr_attr.max_maps)
 565                 list_add(&ibmr->list, &pool->drop_list);
 566         else
 567                 list_add(&ibmr->list, &pool->free_list);
 568
 569         atomic_add(ibmr->sg_len, &pool->free_pinned);
 570         atomic_inc(&pool->dirty_count);
 571         spin_unlock_irqrestore(&pool->list_lock, flags);
 572
 573         /* If we've pinned too many pages, request a flush */
 574         if (atomic_read(&pool->free_pinned) >= pool->max_free_pinned ||
 575             atomic_read(&pool->dirty_count) >= pool->max_items / 10)
 576                 queue_work(rds_wq, &pool->flush_worker);
 577
 578         if (invalidate) {
 579                 if (likely(!in_interrupt())) {
 580                         rds_ib_flush_mr_pool(pool, 0);
 581                 } else {
 582                         /* We get here if the user created a MR marked
 583                          * as use_once and invalidate at the same time. */
 584                         queue_work(rds_wq, &pool->flush_worker);
 585                 }
 586         }
 587 }
 588
 589 void rds_ib_flush_mrs(void)
 590 {
 591         struct rds_ib_device *rds_ibdev;
 592
 593         list_for_each_entry(rds_ibdev, &rds_ib_devices, list) {
 594                 struct rds_ib_mr_pool *pool = rds_ibdev->mr_pool;
 595
 596                 if (pool)
 597                         rds_ib_flush_mr_pool(pool, 0);
 598         }
 599 }
 600
 601 void *rds_ib_get_mr(struct scatterlist *sg, unsigned long nents,
 602                     struct rds_sock *rs, u32 *key_ret)
 603 {
 604         struct rds_ib_device *rds_ibdev;
 605         struct rds_ib_mr *ibmr = NULL;
 606         int ret;
 607
 608         rds_ibdev = rds_ib_get_device(rs->rs_bound_addr);
 609         if (!rds_ibdev) {
 610                 ret = -ENODEV;
 611                 goto out;
 612         }
 613
 614         if (!rds_ibdev->mr_pool) {
 615                 ret = -ENODEV;
 616                 goto out;
 617         }
 618
 619         ibmr = rds_ib_alloc_fmr(rds_ibdev);
 620         if (IS_ERR(ibmr))
 621                 return ibmr;
 622
 623         ret = rds_ib_map_fmr(rds_ibdev, ibmr, sg, nents);
 624         if (ret == 0)
 625                 *key_ret = ibmr->fmr->rkey;
 626         else
 627                 printk(KERN_WARNING "RDS/IB: map_fmr failed (errno=%d)\n", ret);
 628
 629         ibmr->device = rds_ibdev;
 630
 631  out:
 632         if (ret) {
 633                 if (ibmr)
 634                         rds_ib_free_mr(ibmr, 0);
 635                 ibmr = ERR_PTR(ret);
 636         }
 637         return ibmr;
 638 }