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 #include <linux/llist.h>
  37
  38 #include "rds.h"
  39 #include "ib.h"
  40
  41 static DEFINE_PER_CPU(unsigned long, clean_list_grace);
  42 #define CLEAN_LIST_BUSY_BIT 0
  43
  44 /*
  45  * This is stored as mr->r_trans_private.
  46  */
  47 struct rds_ib_mr {
  48         struct rds_ib_device    *device;
  49         struct rds_ib_mr_pool   *pool;
  50         struct ib_fmr           *fmr;
  51
  52         struct llist_node       llnode;
  53
  54         /* unmap_list is for freeing */
  55         struct list_head        unmap_list;
  56         unsigned int            remap_count;
  57
  58         struct scatterlist      *sg;
  59         unsigned int            sg_len;
  60         u64                     *dma;
  61         int                     sg_dma_len;
  62 };
  63
  64 /*
  65  * Our own little FMR pool
  66  */
  67 struct rds_ib_mr_pool {
  68         struct mutex            flush_lock;             /* serialize fmr invalidate */
  69         struct delayed_work     flush_worker;           /* flush worker */
  70
  71         atomic_t                item_count;             /* total # of MRs */
  72         atomic_t                dirty_count;            /* # dirty of MRs */
  73
  74         struct llist_head       drop_list;              /* MRs that have reached their max_maps limit */
  75         struct llist_head       free_list;              /* unused MRs */
  76         struct llist_head       clean_list;             /* global unused & unamapped MRs */
  77         wait_queue_head_t       flush_wait;
  78
  79         atomic_t                free_pinned;            /* memory pinned by free MRs */
  80         unsigned long           max_items;
  81         unsigned long           max_items_soft;
  82         unsigned long           max_free_pinned;
  83         struct ib_fmr_attr      fmr_attr;
  84 };
  85
  86 struct workqueue_struct *rds_ib_fmr_wq;
  87
  88 int rds_ib_fmr_init(void)
  89 {
  90         rds_ib_fmr_wq = create_workqueue("rds_fmr_flushd");
  91         if (!rds_ib_fmr_wq)
  92                 return -ENOMEM;
  93         return 0;
  94 }
  95
  96 /* By the time this is called all the IB devices should have been torn down and
  97  * had their pools freed.  As each pool is freed its work struct is waited on,
  98  * so the pool flushing work queue should be idle by the time we get here.
  99  */
 100 void rds_ib_fmr_exit(void)
 101 {
 102         destroy_workqueue(rds_ib_fmr_wq);
 103 }
 104
 105 static int rds_ib_flush_mr_pool(struct rds_ib_mr_pool *pool, int free_all, struct rds_ib_mr **);
 106 static void rds_ib_teardown_mr(struct rds_ib_mr *ibmr);
 107 static void rds_ib_mr_pool_flush_worker(struct work_struct *work);
 108
 109 static struct rds_ib_device *rds_ib_get_device(__be32 ipaddr)
 110 {
 111         struct rds_ib_device *rds_ibdev;
 112         struct rds_ib_ipaddr *i_ipaddr;
 113
 114         rcu_read_lock();
 115         list_for_each_entry_rcu(rds_ibdev, &rds_ib_devices, list) {
 116                 list_for_each_entry_rcu(i_ipaddr, &rds_ibdev->ipaddr_list, list) {
 117                         if (i_ipaddr->ipaddr == ipaddr) {
 118                                 atomic_inc(&rds_ibdev->refcount);
 119                                 rcu_read_unlock();
 120                                 return rds_ibdev;
 121                         }
 122                 }
 123         }
 124         rcu_read_unlock();
 125
 126         return NULL;
 127 }
 128
 129 static int rds_ib_add_ipaddr(struct rds_ib_device *rds_ibdev, __be32 ipaddr)
 130 {
 131         struct rds_ib_ipaddr *i_ipaddr;
 132
 133         i_ipaddr = kmalloc(sizeof *i_ipaddr, GFP_KERNEL);
 134         if (!i_ipaddr)
 135                 return -ENOMEM;
 136
 137         i_ipaddr->ipaddr = ipaddr;
 138
 139         spin_lock_irq(&rds_ibdev->spinlock);
 140         list_add_tail_rcu(&i_ipaddr->list, &rds_ibdev->ipaddr_list);
 141         spin_unlock_irq(&rds_ibdev->spinlock);
 142
 143         return 0;
 144 }
 145
 146 static void rds_ib_remove_ipaddr(struct rds_ib_device *rds_ibdev, __be32 ipaddr)
 147 {
 148         struct rds_ib_ipaddr *i_ipaddr;
 149         struct rds_ib_ipaddr *to_free = NULL;
 150
 151
 152         spin_lock_irq(&rds_ibdev->spinlock);
 153         list_for_each_entry_rcu(i_ipaddr, &rds_ibdev->ipaddr_list, list) {
 154                 if (i_ipaddr->ipaddr == ipaddr) {
 155                         list_del_rcu(&i_ipaddr->list);
 156                         to_free = i_ipaddr;
 157                         break;
 158                 }
 159         }
 160         spin_unlock_irq(&rds_ibdev->spinlock);
 161
 162         if (to_free) {
 163                 synchronize_rcu();
 164                 kfree(to_free);
 165         }
 166 }
 167
 168 int rds_ib_update_ipaddr(struct rds_ib_device *rds_ibdev, __be32 ipaddr)
 169 {
 170         struct rds_ib_device *rds_ibdev_old;
 171
 172         rds_ibdev_old = rds_ib_get_device(ipaddr);
 173         if (!rds_ibdev_old)
 174                 return rds_ib_add_ipaddr(rds_ibdev, ipaddr);
 175
 176         if (rds_ibdev_old != rds_ibdev) {
 177                 rds_ib_remove_ipaddr(rds_ibdev_old, ipaddr);
 178                 rds_ib_dev_put(rds_ibdev_old);
 179                 return rds_ib_add_ipaddr(rds_ibdev, ipaddr);
 180         }
 181         rds_ib_dev_put(rds_ibdev_old);
 182
 183         return 0;
 184 }
 185
 186 void rds_ib_add_conn(struct rds_ib_device *rds_ibdev, struct rds_connection *conn)
 187 {
 188         struct rds_ib_connection *ic = conn->c_transport_data;
 189
 190         /* conn was previously on the nodev_conns_list */
 191         spin_lock_irq(&ib_nodev_conns_lock);
 192         BUG_ON(list_empty(&ib_nodev_conns));
 193         BUG_ON(list_empty(&ic->ib_node));
 194         list_del(&ic->ib_node);
 195
 196         spin_lock(&rds_ibdev->spinlock);
 197         list_add_tail(&ic->ib_node, &rds_ibdev->conn_list);
 198         spin_unlock(&rds_ibdev->spinlock);
 199         spin_unlock_irq(&ib_nodev_conns_lock);
 200
 201         ic->rds_ibdev = rds_ibdev;
 202         atomic_inc(&rds_ibdev->refcount);
 203 }
 204
 205 void rds_ib_remove_conn(struct rds_ib_device *rds_ibdev, struct rds_connection *conn)
 206 {
 207         struct rds_ib_connection *ic = conn->c_transport_data;
 208
 209         /* place conn on nodev_conns_list */
 210         spin_lock(&ib_nodev_conns_lock);
 211
 212         spin_lock_irq(&rds_ibdev->spinlock);
 213         BUG_ON(list_empty(&ic->ib_node));
 214         list_del(&ic->ib_node);
 215         spin_unlock_irq(&rds_ibdev->spinlock);
 216
 217         list_add_tail(&ic->ib_node, &ib_nodev_conns);
 218
 219         spin_unlock(&ib_nodev_conns_lock);
 220
 221         ic->rds_ibdev = NULL;
 222         rds_ib_dev_put(rds_ibdev);
 223 }
 224
 225 void rds_ib_destroy_nodev_conns(void)
 226 {
 227         struct rds_ib_connection *ic, *_ic;
 228         LIST_HEAD(tmp_list);
 229
 230         /* avoid calling conn_destroy with irqs off */
 231         spin_lock_irq(&ib_nodev_conns_lock);
 232         list_splice(&ib_nodev_conns, &tmp_list);
 233         spin_unlock_irq(&ib_nodev_conns_lock);
 234
 235         list_for_each_entry_safe(ic, _ic, &tmp_list, ib_node)
 236                 rds_conn_destroy(ic->conn);
 237 }
 238
 239 struct rds_ib_mr_pool *rds_ib_create_mr_pool(struct rds_ib_device *rds_ibdev)
 240 {
 241         struct rds_ib_mr_pool *pool;
 242
 243         pool = kzalloc(sizeof(*pool), GFP_KERNEL);
 244         if (!pool)
 245                 return ERR_PTR(-ENOMEM);
 246
 247         init_llist_head(&pool->free_list);
 248         init_llist_head(&pool->drop_list);
 249         init_llist_head(&pool->clean_list);
 250         mutex_init(&pool->flush_lock);
 251         init_waitqueue_head(&pool->flush_wait);
 252         INIT_DELAYED_WORK(&pool->flush_worker, rds_ib_mr_pool_flush_worker);
 253
 254         pool->fmr_attr.max_pages = fmr_message_size;
 255         pool->fmr_attr.max_maps = rds_ibdev->fmr_max_remaps;
 256         pool->fmr_attr.page_shift = PAGE_SHIFT;
 257         pool->max_free_pinned = rds_ibdev->max_fmrs * fmr_message_size / 4;
 258
 259         /* We never allow more than max_items MRs to be allocated.
 260          * When we exceed more than max_items_soft, we start freeing
 261          * items more aggressively.
 262          * Make sure that max_items > max_items_soft > max_items / 2
 263          */
 264         pool->max_items_soft = rds_ibdev->max_fmrs * 3 / 4;
 265         pool->max_items = rds_ibdev->max_fmrs;
 266
 267         return pool;
 268 }
 269
 270 void rds_ib_get_mr_info(struct rds_ib_device *rds_ibdev, struct rds_info_rdma_connection *iinfo)
 271 {
 272         struct rds_ib_mr_pool *pool = rds_ibdev->mr_pool;
 273
 274         iinfo->rdma_mr_max = pool->max_items;
 275         iinfo->rdma_mr_size = pool->fmr_attr.max_pages;
 276 }
 277
 278 void rds_ib_destroy_mr_pool(struct rds_ib_mr_pool *pool)
 279 {
 280         cancel_delayed_work_sync(&pool->flush_worker);
 281         rds_ib_flush_mr_pool(pool, 1, NULL);
 282         WARN_ON(atomic_read(&pool->item_count));
 283         WARN_ON(atomic_read(&pool->free_pinned));
 284         kfree(pool);
 285 }
 286
 287 static inline struct rds_ib_mr *rds_ib_reuse_fmr(struct rds_ib_mr_pool *pool)
 288 {
 289         struct rds_ib_mr *ibmr = NULL;
 290         struct llist_node *ret;
 291         unsigned long *flag;
 292
 293         preempt_disable();
 294         flag = this_cpu_ptr(&clean_list_grace);
 295         set_bit(CLEAN_LIST_BUSY_BIT, flag);
 296         ret = llist_del_first(&pool->clean_list);
 297         if (ret)
 298                 ibmr = llist_entry(ret, struct rds_ib_mr, llnode);
 299
 300         clear_bit(CLEAN_LIST_BUSY_BIT, flag);
 301         preempt_enable();
 302         return ibmr;
 303 }
 304
 305 static inline void wait_clean_list_grace(void)
 306 {
 307         int cpu;
 308         unsigned long *flag;
 309
 310         for_each_online_cpu(cpu) {
 311                 flag = &per_cpu(clean_list_grace, cpu);
 312                 while (test_bit(CLEAN_LIST_BUSY_BIT, flag))
 313                         cpu_relax();
 314         }
 315 }
 316
 317 static struct rds_ib_mr *rds_ib_alloc_fmr(struct rds_ib_device *rds_ibdev)
 318 {
 319         struct rds_ib_mr_pool *pool = rds_ibdev->mr_pool;
 320         struct rds_ib_mr *ibmr = NULL;
 321         int err = 0, iter = 0;
 322
 323         if (atomic_read(&pool->dirty_count) >= pool->max_items / 10)
 324                 schedule_delayed_work(&pool->flush_worker, 10);
 325
 326         while (1) {
 327                 ibmr = rds_ib_reuse_fmr(pool);
 328                 if (ibmr)
 329                         return ibmr;
 330
 331                 /* No clean MRs - now we have the choice of either
 332                  * allocating a fresh MR up to the limit imposed by the
 333                  * driver, or flush any dirty unused MRs.
 334                  * We try to avoid stalling in the send path if possible,
 335                  * so we allocate as long as we're allowed to.
 336                  *
 337                  * We're fussy with enforcing the FMR limit, though. If the driver
 338                  * tells us we can't use more than N fmrs, we shouldn't start
 339                  * arguing with it */
 340                 if (atomic_inc_return(&pool->item_count) <= pool->max_items)
 341                         break;
 342
 343                 atomic_dec(&pool->item_count);
 344
 345                 if (++iter > 2) {
 346                         rds_ib_stats_inc(s_ib_rdma_mr_pool_depleted);
 347                         return ERR_PTR(-EAGAIN);
 348                 }
 349
 350                 /* We do have some empty MRs. Flush them out. */
 351                 rds_ib_stats_inc(s_ib_rdma_mr_pool_wait);
 352                 rds_ib_flush_mr_pool(pool, 0, &ibmr);
 353                 if (ibmr)
 354                         return ibmr;
 355         }
 356
 357         ibmr = kzalloc_node(sizeof(*ibmr), GFP_KERNEL, rdsibdev_to_node(rds_ibdev));
 358         if (!ibmr) {
 359                 err = -ENOMEM;
 360                 goto out_no_cigar;
 361         }
 362
 363         ibmr->fmr = ib_alloc_fmr(rds_ibdev->pd,
 364                         (IB_ACCESS_LOCAL_WRITE |
 365                          IB_ACCESS_REMOTE_READ |
 366                          IB_ACCESS_REMOTE_WRITE|
 367                          IB_ACCESS_REMOTE_ATOMIC),
 368                         &pool->fmr_attr);
 369         if (IS_ERR(ibmr->fmr)) {
 370                 err = PTR_ERR(ibmr->fmr);
 371                 ibmr->fmr = NULL;
 372                 printk(KERN_WARNING "RDS/IB: ib_alloc_fmr failed (err=%d)\n", err);
 373                 goto out_no_cigar;
 374         }
 375
 376         rds_ib_stats_inc(s_ib_rdma_mr_alloc);
 377         return ibmr;
 378
 379 out_no_cigar:
 380         if (ibmr) {
 381                 if (ibmr->fmr)
 382                         ib_dealloc_fmr(ibmr->fmr);
 383                 kfree(ibmr);
 384         }
 385         atomic_dec(&pool->item_count);
 386         return ERR_PTR(err);
 387 }
 388
 389 static int rds_ib_map_fmr(struct rds_ib_device *rds_ibdev, struct rds_ib_mr *ibmr,
 390                struct scatterlist *sg, unsigned int nents)
 391 {
 392         struct ib_device *dev = rds_ibdev->dev;
 393         struct scatterlist *scat = sg;
 394         u64 io_addr = 0;
 395         u64 *dma_pages;
 396         u32 len;
 397         int page_cnt, sg_dma_len;
 398         int i, j;
 399         int ret;
 400
 401         sg_dma_len = ib_dma_map_sg(dev, sg, nents,
 402                                  DMA_BIDIRECTIONAL);
 403         if (unlikely(!sg_dma_len)) {
 404                 printk(KERN_WARNING "RDS/IB: dma_map_sg failed!\n");
 405                 return -EBUSY;
 406         }
 407
 408         len = 0;
 409         page_cnt = 0;
 410
 411         for (i = 0; i < sg_dma_len; ++i) {
 412                 unsigned int dma_len = ib_sg_dma_len(dev, &scat[i]);
 413                 u64 dma_addr = ib_sg_dma_address(dev, &scat[i]);
 414
 415                 if (dma_addr & ~PAGE_MASK) {
 416                         if (i > 0)
 417                                 return -EINVAL;
 418                         else
 419                                 ++page_cnt;
 420                 }
 421                 if ((dma_addr + dma_len) & ~PAGE_MASK) {
 422                         if (i < sg_dma_len - 1)
 423                                 return -EINVAL;
 424                         else
 425                                 ++page_cnt;
 426                 }
 427
 428                 len += dma_len;
 429         }
 430
 431         page_cnt += len >> PAGE_SHIFT;
 432         if (page_cnt > fmr_message_size)
 433                 return -EINVAL;
 434
 435         dma_pages = kmalloc_node(sizeof(u64) * page_cnt, GFP_ATOMIC,
 436                                  rdsibdev_to_node(rds_ibdev));
 437         if (!dma_pages)
 438                 return -ENOMEM;
 439
 440         page_cnt = 0;
 441         for (i = 0; i < sg_dma_len; ++i) {
 442                 unsigned int dma_len = ib_sg_dma_len(dev, &scat[i]);
 443                 u64 dma_addr = ib_sg_dma_address(dev, &scat[i]);
 444
 445                 for (j = 0; j < dma_len; j += PAGE_SIZE)
 446                         dma_pages[page_cnt++] =
 447                                 (dma_addr & PAGE_MASK) + j;
 448         }
 449
 450         ret = ib_map_phys_fmr(ibmr->fmr,
 451                                    dma_pages, page_cnt, io_addr);
 452         if (ret)
 453                 goto out;
 454
 455         /* Success - we successfully remapped the MR, so we can
 456          * safely tear down the old mapping. */
 457         rds_ib_teardown_mr(ibmr);
 458
 459         ibmr->sg = scat;
 460         ibmr->sg_len = nents;
 461         ibmr->sg_dma_len = sg_dma_len;
 462         ibmr->remap_count++;
 463
 464         rds_ib_stats_inc(s_ib_rdma_mr_used);
 465         ret = 0;
 466
 467 out:
 468         kfree(dma_pages);
 469
 470         return ret;
 471 }
 472
 473 void rds_ib_sync_mr(void *trans_private, int direction)
 474 {
 475         struct rds_ib_mr *ibmr = trans_private;
 476         struct rds_ib_device *rds_ibdev = ibmr->device;
 477
 478         switch (direction) {
 479         case DMA_FROM_DEVICE:
 480                 ib_dma_sync_sg_for_cpu(rds_ibdev->dev, ibmr->sg,
 481                         ibmr->sg_dma_len, DMA_BIDIRECTIONAL);
 482                 break;
 483         case DMA_TO_DEVICE:
 484                 ib_dma_sync_sg_for_device(rds_ibdev->dev, ibmr->sg,
 485                         ibmr->sg_dma_len, DMA_BIDIRECTIONAL);
 486                 break;
 487         }
 488 }
 489
 490 static void __rds_ib_teardown_mr(struct rds_ib_mr *ibmr)
 491 {
 492         struct rds_ib_device *rds_ibdev = ibmr->device;
 493
 494         if (ibmr->sg_dma_len) {
 495                 ib_dma_unmap_sg(rds_ibdev->dev,
 496                                 ibmr->sg, ibmr->sg_len,
 497                                 DMA_BIDIRECTIONAL);
 498                 ibmr->sg_dma_len = 0;
 499         }
 500
 501         /* Release the s/g list */
 502         if (ibmr->sg_len) {
 503                 unsigned int i;
 504
 505                 for (i = 0; i < ibmr->sg_len; ++i) {
 506                         struct page *page = sg_page(&ibmr->sg[i]);
 507
 508                         /* FIXME we need a way to tell a r/w MR
 509                          * from a r/o MR */
 510                         WARN_ON(!page->mapping && irqs_disabled());
 511                         set_page_dirty(page);
 512                         put_page(page);
 513                 }
 514                 kfree(ibmr->sg);
 515
 516                 ibmr->sg = NULL;
 517                 ibmr->sg_len = 0;
 518         }
 519 }
 520
 521 static void rds_ib_teardown_mr(struct rds_ib_mr *ibmr)
 522 {
 523         unsigned int pinned = ibmr->sg_len;
 524
 525         __rds_ib_teardown_mr(ibmr);
 526         if (pinned) {
 527                 struct rds_ib_device *rds_ibdev = ibmr->device;
 528                 struct rds_ib_mr_pool *pool = rds_ibdev->mr_pool;
 529
 530                 atomic_sub(pinned, &pool->free_pinned);
 531         }
 532 }
 533
 534 static inline unsigned int rds_ib_flush_goal(struct rds_ib_mr_pool *pool, int free_all)
 535 {
 536         unsigned int item_count;
 537
 538         item_count = atomic_read(&pool->item_count);
 539         if (free_all)
 540                 return item_count;
 541
 542         return 0;
 543 }
 544
 545 /*
 546  * given an llist of mrs, put them all into the list_head for more processing
 547  */
 548 static unsigned int llist_append_to_list(struct llist_head *llist,
 549                                          struct list_head *list)
 550 {
 551         struct rds_ib_mr *ibmr;
 552         struct llist_node *node;
 553         struct llist_node *next;
 554         unsigned int count = 0;
 555
 556         node = llist_del_all(llist);
 557         while (node) {
 558                 next = node->next;
 559                 ibmr = llist_entry(node, struct rds_ib_mr, llnode);
 560                 list_add_tail(&ibmr->unmap_list, list);
 561                 node = next;
 562                 count++;
 563         }
 564         return count;
 565 }
 566
 567 /*
 568  * this takes a list head of mrs and turns it into linked llist nodes
 569  * of clusters.  Each cluster has linked llist nodes of
 570  * MR_CLUSTER_SIZE mrs that are ready for reuse.
 571  */
 572 static void list_to_llist_nodes(struct rds_ib_mr_pool *pool,
 573                                 struct list_head *list,
 574                                 struct llist_node **nodes_head,
 575                                 struct llist_node **nodes_tail)
 576 {
 577         struct rds_ib_mr *ibmr;
 578         struct llist_node *cur = NULL;
 579         struct llist_node **next = nodes_head;
 580
 581         list_for_each_entry(ibmr, list, unmap_list) {
 582                 cur = &ibmr->llnode;
 583                 *next = cur;
 584                 next = &cur->next;
 585         }
 586         *next = NULL;
 587         *nodes_tail = cur;
 588 }
 589
 590 /*
 591  * Flush our pool of MRs.
 592  * At a minimum, all currently unused MRs are unmapped.
 593  * If the number of MRs allocated exceeds the limit, we also try
 594  * to free as many MRs as needed to get back to this limit.
 595  */
 596 static int rds_ib_flush_mr_pool(struct rds_ib_mr_pool *pool,
 597                                 int free_all, struct rds_ib_mr **ibmr_ret)
 598 {
 599         struct rds_ib_mr *ibmr, *next;
 600         struct llist_node *clean_nodes;
 601         struct llist_node *clean_tail;
 602         LIST_HEAD(unmap_list);
 603         LIST_HEAD(fmr_list);
 604         unsigned long unpinned = 0;
 605         unsigned int nfreed = 0, dirty_to_clean = 0, free_goal;
 606         int ret = 0;
 607
 608         rds_ib_stats_inc(s_ib_rdma_mr_pool_flush);
 609
 610         if (ibmr_ret) {
 611                 DEFINE_WAIT(wait);
 612                 while(!mutex_trylock(&pool->flush_lock)) {
 613                         ibmr = rds_ib_reuse_fmr(pool);
 614                         if (ibmr) {
 615                                 *ibmr_ret = ibmr;
 616                                 finish_wait(&pool->flush_wait, &wait);
 617                                 goto out_nolock;
 618                         }
 619
 620                         prepare_to_wait(&pool->flush_wait, &wait,
 621                                         TASK_UNINTERRUPTIBLE);
 622                         if (llist_empty(&pool->clean_list))
 623                                 schedule();
 624
 625                         ibmr = rds_ib_reuse_fmr(pool);
 626                         if (ibmr) {
 627                                 *ibmr_ret = ibmr;
 628                                 finish_wait(&pool->flush_wait, &wait);
 629                                 goto out_nolock;
 630                         }
 631                 }
 632                 finish_wait(&pool->flush_wait, &wait);
 633         } else
 634                 mutex_lock(&pool->flush_lock);
 635
 636         if (ibmr_ret) {
 637                 ibmr = rds_ib_reuse_fmr(pool);
 638                 if (ibmr) {
 639                         *ibmr_ret = ibmr;
 640                         goto out;
 641                 }
 642         }
 643
 644         /* Get the list of all MRs to be dropped. Ordering matters -
 645          * we want to put drop_list ahead of free_list.
 646          */
 647         dirty_to_clean = llist_append_to_list(&pool->drop_list, &unmap_list);
 648         dirty_to_clean += llist_append_to_list(&pool->free_list, &unmap_list);
 649         if (free_all)
 650                 llist_append_to_list(&pool->clean_list, &unmap_list);
 651
 652         free_goal = rds_ib_flush_goal(pool, free_all);
 653
 654         if (list_empty(&unmap_list))
 655                 goto out;
 656
 657         /* String all ib_mr's onto one list and hand them to ib_unmap_fmr */
 658         list_for_each_entry(ibmr, &unmap_list, unmap_list)
 659                 list_add(&ibmr->fmr->list, &fmr_list);
 660
 661         ret = ib_unmap_fmr(&fmr_list);
 662         if (ret)
 663                 printk(KERN_WARNING "RDS/IB: ib_unmap_fmr failed (err=%d)\n", ret);
 664
 665         /* Now we can destroy the DMA mapping and unpin any pages */
 666         list_for_each_entry_safe(ibmr, next, &unmap_list, unmap_list) {
 667                 unpinned += ibmr->sg_len;
 668                 __rds_ib_teardown_mr(ibmr);
 669                 if (nfreed < free_goal || ibmr->remap_count >= pool->fmr_attr.max_maps) {
 670                         rds_ib_stats_inc(s_ib_rdma_mr_free);
 671                         list_del(&ibmr->unmap_list);
 672                         ib_dealloc_fmr(ibmr->fmr);
 673                         kfree(ibmr);
 674                         nfreed++;
 675                 }
 676         }
 677
 678         if (!list_empty(&unmap_list)) {
 679                 /* we have to make sure that none of the things we're about
 680                  * to put on the clean list would race with other cpus trying
 681                  * to pull items off.  The llist would explode if we managed to
 682                  * remove something from the clean list and then add it back again
 683                  * while another CPU was spinning on that same item in llist_del_first.
 684                  *
 685                  * This is pretty unlikely, but just in case  wait for an llist grace period
 686                  * here before adding anything back into the clean list.
 687                  */
 688                 wait_clean_list_grace();
 689
 690                 list_to_llist_nodes(pool, &unmap_list, &clean_nodes, &clean_tail);
 691                 if (ibmr_ret)
 692                         *ibmr_ret = llist_entry(clean_nodes, struct rds_ib_mr, llnode);
 693
 694                 /* more than one entry in llist nodes */
 695                 if (clean_nodes->next)
 696                         llist_add_batch(clean_nodes->next, clean_tail, &pool->clean_list);
 697
 698         }
 699
 700         atomic_sub(unpinned, &pool->free_pinned);
 701         atomic_sub(dirty_to_clean, &pool->dirty_count);
 702         atomic_sub(nfreed, &pool->item_count);
 703
 704 out:
 705         mutex_unlock(&pool->flush_lock);
 706         if (waitqueue_active(&pool->flush_wait))
 707                 wake_up(&pool->flush_wait);
 708 out_nolock:
 709         return ret;
 710 }
 711
 712 static void rds_ib_mr_pool_flush_worker(struct work_struct *work)
 713 {
 714         struct rds_ib_mr_pool *pool = container_of(work, struct rds_ib_mr_pool, flush_worker.work);
 715
 716         rds_ib_flush_mr_pool(pool, 0, NULL);
 717 }
 718
 719 void rds_ib_free_mr(void *trans_private, int invalidate)
 720 {
 721         struct rds_ib_mr *ibmr = trans_private;
 722         struct rds_ib_device *rds_ibdev = ibmr->device;
 723         struct rds_ib_mr_pool *pool = rds_ibdev->mr_pool;
 724
 725         rdsdebug("RDS/IB: free_mr nents %u\n", ibmr->sg_len);
 726
 727         /* Return it to the pool's free list */
 728         if (ibmr->remap_count >= pool->fmr_attr.max_maps)
 729                 llist_add(&ibmr->llnode, &pool->drop_list);
 730         else
 731                 llist_add(&ibmr->llnode, &pool->free_list);
 732
 733         atomic_add(ibmr->sg_len, &pool->free_pinned);
 734         atomic_inc(&pool->dirty_count);
 735
 736         /* If we've pinned too many pages, request a flush */
 737         if (atomic_read(&pool->free_pinned) >= pool->max_free_pinned ||
 738             atomic_read(&pool->dirty_count) >= pool->max_items / 5)
 739                 queue_delayed_work(rds_ib_fmr_wq, &pool->flush_worker, 10);
 740
 741         if (invalidate) {
 742                 if (likely(!in_interrupt())) {
 743                         rds_ib_flush_mr_pool(pool, 0, NULL);
 744                 } else {
 745                         /* We get here if the user created a MR marked
 746                          * as use_once and invalidate at the same time.
 747                          */
 748                         queue_delayed_work(rds_ib_fmr_wq,
 749                                            &pool->flush_worker, 10);
 750                 }
 751         }
 752
 753         rds_ib_dev_put(rds_ibdev);
 754 }
 755
 756 void rds_ib_flush_mrs(void)
 757 {
 758         struct rds_ib_device *rds_ibdev;
 759
 760         down_read(&rds_ib_devices_lock);
 761         list_for_each_entry(rds_ibdev, &rds_ib_devices, list) {
 762                 struct rds_ib_mr_pool *pool = rds_ibdev->mr_pool;
 763
 764                 if (pool)
 765                         rds_ib_flush_mr_pool(pool, 0, NULL);
 766         }
 767         up_read(&rds_ib_devices_lock);
 768 }
 769
 770 void *rds_ib_get_mr(struct scatterlist *sg, unsigned long nents,
 771                     struct rds_sock *rs, u32 *key_ret)
 772 {
 773         struct rds_ib_device *rds_ibdev;
 774         struct rds_ib_mr *ibmr = NULL;
 775         int ret;
 776
 777         rds_ibdev = rds_ib_get_device(rs->rs_bound_addr);
 778         if (!rds_ibdev) {
 779                 ret = -ENODEV;
 780                 goto out;
 781         }
 782
 783         if (!rds_ibdev->mr_pool) {
 784                 ret = -ENODEV;
 785                 goto out;
 786         }
 787
 788         ibmr = rds_ib_alloc_fmr(rds_ibdev);
 789         if (IS_ERR(ibmr)) {
 790                 rds_ib_dev_put(rds_ibdev);
 791                 return ibmr;
 792         }
 793
 794         ret = rds_ib_map_fmr(rds_ibdev, ibmr, sg, nents);
 795         if (ret == 0)
 796                 *key_ret = ibmr->fmr->rkey;
 797         else
 798                 printk(KERN_WARNING "RDS/IB: map_fmr failed (errno=%d)\n", ret);
 799
 800         ibmr->device = rds_ibdev;
 801         rds_ibdev = NULL;
 802
 803  out:
 804         if (ret) {
 805                 if (ibmr)
 806                         rds_ib_free_mr(ibmr, 0);
 807                 ibmr = ERR_PTR(ret);
 808         }
 809         if (rds_ibdev)
 810                 rds_ib_dev_put(rds_ibdev);
 811         return ibmr;
 812 }
 813