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(sizeof(*ibmr), GFP_KERNEL);
 301         if (!ibmr) {
 302                 err = -ENOMEM;
 303                 goto out_no_cigar;
 304         }
 305
 306         ibmr->fmr = ib_alloc_fmr(rds_ibdev->pd,
 307                         (IB_ACCESS_LOCAL_WRITE |
 308                          IB_ACCESS_REMOTE_READ |
 309                          IB_ACCESS_REMOTE_WRITE|
 310                          IB_ACCESS_REMOTE_ATOMIC),
 311
 312                         &pool->fmr_attr);
 313         if (IS_ERR(ibmr->fmr)) {
 314                 err = PTR_ERR(ibmr->fmr);
 315                 ibmr->fmr = NULL;
 316                 printk(KERN_WARNING "RDS/IB: ib_alloc_fmr failed (err=%d)\n", err);
 317                 goto out_no_cigar;
 318         }
 319
 320         rds_ib_stats_inc(s_ib_rdma_mr_alloc);
 321         return ibmr;
 322
 323 out_no_cigar:
 324         if (ibmr) {
 325                 if (ibmr->fmr)
 326                         ib_dealloc_fmr(ibmr->fmr);
 327                 kfree(ibmr);
 328         }
 329         atomic_dec(&pool->item_count);
 330         return ERR_PTR(err);
 331 }
 332
 333 static int rds_ib_map_fmr(struct rds_ib_device *rds_ibdev, struct rds_ib_mr *ibmr,
 334                struct scatterlist *sg, unsigned int nents)
 335 {
 336         struct ib_device *dev = rds_ibdev->dev;
 337         struct scatterlist *scat = sg;
 338         u64 io_addr = 0;
 339         u64 *dma_pages;
 340         u32 len;
 341         int page_cnt, sg_dma_len;
 342         int i, j;
 343         int ret;
 344
 345         sg_dma_len = ib_dma_map_sg(dev, sg, nents,
 346                                  DMA_BIDIRECTIONAL);
 347         if (unlikely(!sg_dma_len)) {
 348                 printk(KERN_WARNING "RDS/IB: dma_map_sg failed!\n");
 349                 return -EBUSY;
 350         }
 351
 352         len = 0;
 353         page_cnt = 0;
 354
 355         for (i = 0; i < sg_dma_len; ++i) {
 356                 unsigned int dma_len = ib_sg_dma_len(dev, &scat[i]);
 357                 u64 dma_addr = ib_sg_dma_address(dev, &scat[i]);
 358
 359                 if (dma_addr & ~PAGE_MASK) {
 360                         if (i > 0)
 361                                 return -EINVAL;
 362                         else
 363                                 ++page_cnt;
 364                 }
 365                 if ((dma_addr + dma_len) & ~PAGE_MASK) {
 366                         if (i < sg_dma_len - 1)
 367                                 return -EINVAL;
 368                         else
 369                                 ++page_cnt;
 370                 }
 371
 372                 len += dma_len;
 373         }
 374
 375         page_cnt += len >> PAGE_SHIFT;
 376         if (page_cnt > fmr_message_size)
 377                 return -EINVAL;
 378
 379         dma_pages = kmalloc(sizeof(u64) * page_cnt, GFP_ATOMIC);
 380         if (!dma_pages)
 381                 return -ENOMEM;
 382
 383         page_cnt = 0;
 384         for (i = 0; i < sg_dma_len; ++i) {
 385                 unsigned int dma_len = ib_sg_dma_len(dev, &scat[i]);
 386                 u64 dma_addr = ib_sg_dma_address(dev, &scat[i]);
 387
 388                 for (j = 0; j < dma_len; j += PAGE_SIZE)
 389                         dma_pages[page_cnt++] =
 390                                 (dma_addr & PAGE_MASK) + j;
 391         }
 392
 393         ret = ib_map_phys_fmr(ibmr->fmr,
 394                                    dma_pages, page_cnt, io_addr);
 395         if (ret)
 396                 goto out;
 397
 398         /* Success - we successfully remapped the MR, so we can
 399          * safely tear down the old mapping. */
 400         rds_ib_teardown_mr(ibmr);
 401
 402         ibmr->sg = scat;
 403         ibmr->sg_len = nents;
 404         ibmr->sg_dma_len = sg_dma_len;
 405         ibmr->remap_count++;
 406
 407         rds_ib_stats_inc(s_ib_rdma_mr_used);
 408         ret = 0;
 409
 410 out:
 411         kfree(dma_pages);
 412
 413         return ret;
 414 }
 415
 416 void rds_ib_sync_mr(void *trans_private, int direction)
 417 {
 418         struct rds_ib_mr *ibmr = trans_private;
 419         struct rds_ib_device *rds_ibdev = ibmr->device;
 420
 421         switch (direction) {
 422         case DMA_FROM_DEVICE:
 423                 ib_dma_sync_sg_for_cpu(rds_ibdev->dev, ibmr->sg,
 424                         ibmr->sg_dma_len, DMA_BIDIRECTIONAL);
 425                 break;
 426         case DMA_TO_DEVICE:
 427                 ib_dma_sync_sg_for_device(rds_ibdev->dev, ibmr->sg,
 428                         ibmr->sg_dma_len, DMA_BIDIRECTIONAL);
 429                 break;
 430         }
 431 }
 432
 433 static void __rds_ib_teardown_mr(struct rds_ib_mr *ibmr)
 434 {
 435         struct rds_ib_device *rds_ibdev = ibmr->device;
 436
 437         if (ibmr->sg_dma_len) {
 438                 ib_dma_unmap_sg(rds_ibdev->dev,
 439                                 ibmr->sg, ibmr->sg_len,
 440                                 DMA_BIDIRECTIONAL);
 441                 ibmr->sg_dma_len = 0;
 442         }
 443
 444         /* Release the s/g list */
 445         if (ibmr->sg_len) {
 446                 unsigned int i;
 447
 448                 for (i = 0; i < ibmr->sg_len; ++i) {
 449                         struct page *page = sg_page(&ibmr->sg[i]);
 450
 451                         /* FIXME we need a way to tell a r/w MR
 452                          * from a r/o MR */
 453                         BUG_ON(irqs_disabled());
 454                         set_page_dirty(page);
 455                         put_page(page);
 456                 }
 457                 kfree(ibmr->sg);
 458
 459                 ibmr->sg = NULL;
 460                 ibmr->sg_len = 0;
 461         }
 462 }
 463
 464 static void rds_ib_teardown_mr(struct rds_ib_mr *ibmr)
 465 {
 466         unsigned int pinned = ibmr->sg_len;
 467
 468         __rds_ib_teardown_mr(ibmr);
 469         if (pinned) {
 470                 struct rds_ib_device *rds_ibdev = ibmr->device;
 471                 struct rds_ib_mr_pool *pool = rds_ibdev->mr_pool;
 472
 473                 atomic_sub(pinned, &pool->free_pinned);
 474         }
 475 }
 476
 477 static inline unsigned int rds_ib_flush_goal(struct rds_ib_mr_pool *pool, int free_all)
 478 {
 479         unsigned int item_count;
 480
 481         item_count = atomic_read(&pool->item_count);
 482         if (free_all)
 483                 return item_count;
 484
 485         return 0;
 486 }
 487
 488 /*
 489  * Flush our pool of MRs.
 490  * At a minimum, all currently unused MRs are unmapped.
 491  * If the number of MRs allocated exceeds the limit, we also try
 492  * to free as many MRs as needed to get back to this limit.
 493  */
 494 static int rds_ib_flush_mr_pool(struct rds_ib_mr_pool *pool, int free_all)
 495 {
 496         struct rds_ib_mr *ibmr, *next;
 497         LIST_HEAD(unmap_list);
 498         LIST_HEAD(fmr_list);
 499         unsigned long unpinned = 0;
 500         unsigned long flags;
 501         unsigned int nfreed = 0, ncleaned = 0, free_goal;
 502         int ret = 0;
 503
 504         rds_ib_stats_inc(s_ib_rdma_mr_pool_flush);
 505
 506         mutex_lock(&pool->flush_lock);
 507
 508         spin_lock_irqsave(&pool->list_lock, flags);
 509         /* Get the list of all MRs to be dropped. Ordering matters -
 510          * we want to put drop_list ahead of free_list. */
 511         list_splice_init(&pool->free_list, &unmap_list);
 512         list_splice_init(&pool->drop_list, &unmap_list);
 513         if (free_all)
 514                 list_splice_init(&pool->clean_list, &unmap_list);
 515         spin_unlock_irqrestore(&pool->list_lock, flags);
 516
 517         free_goal = rds_ib_flush_goal(pool, free_all);
 518
 519         if (list_empty(&unmap_list))
 520                 goto out;
 521
 522         /* String all ib_mr's onto one list and hand them to ib_unmap_fmr */
 523         list_for_each_entry(ibmr, &unmap_list, list)
 524                 list_add(&ibmr->fmr->list, &fmr_list);
 525         ret = ib_unmap_fmr(&fmr_list);
 526         if (ret)
 527                 printk(KERN_WARNING "RDS/IB: ib_unmap_fmr failed (err=%d)\n", ret);
 528
 529         /* Now we can destroy the DMA mapping and unpin any pages */
 530         list_for_each_entry_safe(ibmr, next, &unmap_list, list) {
 531                 unpinned += ibmr->sg_len;
 532                 __rds_ib_teardown_mr(ibmr);
 533                 if (nfreed < free_goal || ibmr->remap_count >= pool->fmr_attr.max_maps) {
 534                         rds_ib_stats_inc(s_ib_rdma_mr_free);
 535                         list_del(&ibmr->list);
 536                         ib_dealloc_fmr(ibmr->fmr);
 537                         kfree(ibmr);
 538                         nfreed++;
 539                 }
 540                 ncleaned++;
 541         }
 542
 543         spin_lock_irqsave(&pool->list_lock, flags);
 544         list_splice(&unmap_list, &pool->clean_list);
 545         spin_unlock_irqrestore(&pool->list_lock, flags);
 546
 547         atomic_sub(unpinned, &pool->free_pinned);
 548         atomic_sub(ncleaned, &pool->dirty_count);
 549         atomic_sub(nfreed, &pool->item_count);
 550
 551 out:
 552         mutex_unlock(&pool->flush_lock);
 553         return ret;
 554 }
 555
 556 static void rds_ib_mr_pool_flush_worker(struct work_struct *work)
 557 {
 558         struct rds_ib_mr_pool *pool = container_of(work, struct rds_ib_mr_pool, flush_worker);
 559
 560         rds_ib_flush_mr_pool(pool, 0);
 561 }
 562
 563 void rds_ib_free_mr(void *trans_private, int invalidate)
 564 {
 565         struct rds_ib_mr *ibmr = trans_private;
 566         struct rds_ib_device *rds_ibdev = ibmr->device;
 567         struct rds_ib_mr_pool *pool = rds_ibdev->mr_pool;
 568         unsigned long flags;
 569
 570         rdsdebug("RDS/IB: free_mr nents %u\n", ibmr->sg_len);
 571
 572         /* Return it to the pool's free list */
 573         spin_lock_irqsave(&pool->list_lock, flags);
 574         if (ibmr->remap_count >= pool->fmr_attr.max_maps)
 575                 list_add(&ibmr->list, &pool->drop_list);
 576         else
 577                 list_add(&ibmr->list, &pool->free_list);
 578
 579         atomic_add(ibmr->sg_len, &pool->free_pinned);
 580         atomic_inc(&pool->dirty_count);
 581         spin_unlock_irqrestore(&pool->list_lock, flags);
 582
 583         /* If we've pinned too many pages, request a flush */
 584         if (atomic_read(&pool->free_pinned) >= pool->max_free_pinned ||
 585             atomic_read(&pool->dirty_count) >= pool->max_items / 10)
 586                 queue_work(rds_wq, &pool->flush_worker);
 587
 588         if (invalidate) {
 589                 if (likely(!in_interrupt())) {
 590                         rds_ib_flush_mr_pool(pool, 0);
 591                 } else {
 592                         /* We get here if the user created a MR marked
 593                          * as use_once and invalidate at the same time. */
 594                         queue_work(rds_wq, &pool->flush_worker);
 595                 }
 596         }
 597 }
 598
 599 void rds_ib_flush_mrs(void)
 600 {
 601         struct rds_ib_device *rds_ibdev;
 602
 603         list_for_each_entry(rds_ibdev, &rds_ib_devices, list) {
 604                 struct rds_ib_mr_pool *pool = rds_ibdev->mr_pool;
 605
 606                 if (pool)
 607                         rds_ib_flush_mr_pool(pool, 0);
 608         }
 609 }
 610
 611 void *rds_ib_get_mr(struct scatterlist *sg, unsigned long nents,
 612                     struct rds_sock *rs, u32 *key_ret)
 613 {
 614         struct rds_ib_device *rds_ibdev;
 615         struct rds_ib_mr *ibmr = NULL;
 616         int ret;
 617
 618         rds_ibdev = rds_ib_get_device(rs->rs_bound_addr);
 619         if (!rds_ibdev) {
 620                 ret = -ENODEV;
 621                 goto out;
 622         }
 623
 624         if (!rds_ibdev->mr_pool) {
 625                 ret = -ENODEV;
 626                 goto out;
 627         }
 628
 629         ibmr = rds_ib_alloc_fmr(rds_ibdev);
 630         if (IS_ERR(ibmr))
 631                 return ibmr;
 632
 633         ret = rds_ib_map_fmr(rds_ibdev, ibmr, sg, nents);
 634         if (ret == 0)
 635                 *key_ret = ibmr->fmr->rkey;
 636         else
 637                 printk(KERN_WARNING "RDS/IB: map_fmr failed (errno=%d)\n", ret);
 638
 639         ibmr->device = rds_ibdev;
 640
 641  out:
 642         if (ret) {
 643                 if (ibmr)
 644                         rds_ib_free_mr(ibmr, 0);
 645                 ibmr = ERR_PTR(ret);
 646         }
 647         return ibmr;
 648 }