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