net/rds/iw_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/ratelimit.h>
  36
  37 #include "rds.h"
  38 #include "iw.h"
  39
  40
  41 /*
  42  * This is stored as mr->r_trans_private.
  43  */
  44 struct rds_iw_mr {
  45         struct rds_iw_device    *device;
  46         struct rds_iw_mr_pool   *pool;
  47         struct rdma_cm_id       *cm_id;
  48
  49         struct ib_mr    *mr;
  50         struct ib_fast_reg_page_list *page_list;
  51
  52         struct rds_iw_mapping   mapping;
  53         unsigned char           remap_count;
  54 };
  55
  56 /*
  57  * Our own little MR pool
  58  */
  59 struct rds_iw_mr_pool {
  60         struct rds_iw_device    *device;                /* back ptr to the device that owns us */
  61
  62         struct mutex            flush_lock;             /* serialize fmr invalidate */
  63         struct work_struct      flush_worker;           /* flush worker */
  64
  65         spinlock_t              list_lock;              /* protect variables below */
  66         atomic_t                item_count;             /* total # of MRs */
  67         atomic_t                dirty_count;            /* # dirty of MRs */
  68         struct list_head        dirty_list;             /* dirty mappings */
  69         struct list_head        clean_list;             /* unused & unamapped MRs */
  70         atomic_t                free_pinned;            /* memory pinned by free MRs */
  71         unsigned long           max_message_size;       /* in pages */
  72         unsigned long           max_items;
  73         unsigned long           max_items_soft;
  74         unsigned long           max_free_pinned;
  75         int                     max_pages;
  76 };
  77
  78 static int rds_iw_flush_mr_pool(struct rds_iw_mr_pool *pool, int free_all);
  79 static void rds_iw_mr_pool_flush_worker(struct work_struct *work);
  80 static int rds_iw_init_fastreg(struct rds_iw_mr_pool *pool, struct rds_iw_mr *ibmr);
  81 static int rds_iw_map_fastreg(struct rds_iw_mr_pool *pool,
  82                           struct rds_iw_mr *ibmr,
  83                           struct scatterlist *sg, unsigned int nents);
  84 static void rds_iw_free_fastreg(struct rds_iw_mr_pool *pool, struct rds_iw_mr *ibmr);
  85 static unsigned int rds_iw_unmap_fastreg_list(struct rds_iw_mr_pool *pool,
  86                         struct list_head *unmap_list,
  87                         struct list_head *kill_list,
  88                         int *unpinned);
  89 static void rds_iw_destroy_fastreg(struct rds_iw_mr_pool *pool, struct rds_iw_mr *ibmr);
  90
  91 static int rds_iw_get_device(struct rds_sock *rs, struct rds_iw_device **rds_iwdev, struct rdma_cm_id **cm_id)
  92 {
  93         struct rds_iw_device *iwdev;
  94         struct rds_iw_cm_id *i_cm_id;
  95
  96         *rds_iwdev = NULL;
  97         *cm_id = NULL;
  98
  99         list_for_each_entry(iwdev, &rds_iw_devices, list) {
 100                 spin_lock_irq(&iwdev->spinlock);
 101                 list_for_each_entry(i_cm_id, &iwdev->cm_id_list, list) {
 102                         struct sockaddr_in *src_addr, *dst_addr;
 103
 104                         src_addr = (struct sockaddr_in *)&i_cm_id->cm_id->route.addr.src_addr;
 105                         dst_addr = (struct sockaddr_in *)&i_cm_id->cm_id->route.addr.dst_addr;
 106
 107                         rdsdebug("local ipaddr = %x port %d, "
 108                                  "remote ipaddr = %x port %d"
 109                                  "..looking for %x port %d, "
 110                                  "remote ipaddr = %x port %d\n",
 111                                 src_addr->sin_addr.s_addr,
 112                                 src_addr->sin_port,
 113                                 dst_addr->sin_addr.s_addr,
 114                                 dst_addr->sin_port,
 115                                 rs->rs_bound_addr,
 116                                 rs->rs_bound_port,
 117                                 rs->rs_conn_addr,
 118                                 rs->rs_conn_port);
 119 #ifdef WORKING_TUPLE_DETECTION
 120                         if (src_addr->sin_addr.s_addr == rs->rs_bound_addr &&
 121                             src_addr->sin_port == rs->rs_bound_port &&
 122                             dst_addr->sin_addr.s_addr == rs->rs_conn_addr &&
 123                             dst_addr->sin_port == rs->rs_conn_port) {
 124 #else
 125                         /* FIXME - needs to compare the local and remote
 126                          * ipaddr/port tuple, but the ipaddr is the only
 127                          * available information in the rds_sock (as the rest are
 128                          * zero'ed.  It doesn't appear to be properly populated
 129                          * during connection setup...
 130                          */
 131                         if (src_addr->sin_addr.s_addr == rs->rs_bound_addr) {
 132 #endif
 133                                 spin_unlock_irq(&iwdev->spinlock);
 134                                 *rds_iwdev = iwdev;
 135                                 *cm_id = i_cm_id->cm_id;
 136                                 return 0;
 137                         }
 138                 }
 139                 spin_unlock_irq(&iwdev->spinlock);
 140         }
 141
 142         return 1;
 143 }
 144
 145 static int rds_iw_add_cm_id(struct rds_iw_device *rds_iwdev, struct rdma_cm_id *cm_id)
 146 {
 147         struct rds_iw_cm_id *i_cm_id;
 148
 149         i_cm_id = kmalloc(sizeof *i_cm_id, GFP_KERNEL);
 150         if (!i_cm_id)
 151                 return -ENOMEM;
 152
 153         i_cm_id->cm_id = cm_id;
 154
 155         spin_lock_irq(&rds_iwdev->spinlock);
 156         list_add_tail(&i_cm_id->list, &rds_iwdev->cm_id_list);
 157         spin_unlock_irq(&rds_iwdev->spinlock);
 158
 159         return 0;
 160 }
 161
 162 static void rds_iw_remove_cm_id(struct rds_iw_device *rds_iwdev,
 163                                 struct rdma_cm_id *cm_id)
 164 {
 165         struct rds_iw_cm_id *i_cm_id;
 166
 167         spin_lock_irq(&rds_iwdev->spinlock);
 168         list_for_each_entry(i_cm_id, &rds_iwdev->cm_id_list, list) {
 169                 if (i_cm_id->cm_id == cm_id) {
 170                         list_del(&i_cm_id->list);
 171                         kfree(i_cm_id);
 172                         break;
 173                 }
 174         }
 175         spin_unlock_irq(&rds_iwdev->spinlock);
 176 }
 177
 178
 179 int rds_iw_update_cm_id(struct rds_iw_device *rds_iwdev, struct rdma_cm_id *cm_id)
 180 {
 181         struct sockaddr_in *src_addr, *dst_addr;
 182         struct rds_iw_device *rds_iwdev_old;
 183         struct rds_sock rs;
 184         struct rdma_cm_id *pcm_id;
 185         int rc;
 186
 187         src_addr = (struct sockaddr_in *)&cm_id->route.addr.src_addr;
 188         dst_addr = (struct sockaddr_in *)&cm_id->route.addr.dst_addr;
 189
 190         rs.rs_bound_addr = src_addr->sin_addr.s_addr;
 191         rs.rs_bound_port = src_addr->sin_port;
 192         rs.rs_conn_addr = dst_addr->sin_addr.s_addr;
 193         rs.rs_conn_port = dst_addr->sin_port;
 194
 195         rc = rds_iw_get_device(&rs, &rds_iwdev_old, &pcm_id);
 196         if (rc)
 197                 rds_iw_remove_cm_id(rds_iwdev, cm_id);
 198
 199         return rds_iw_add_cm_id(rds_iwdev, cm_id);
 200 }
 201
 202 void rds_iw_add_conn(struct rds_iw_device *rds_iwdev, struct rds_connection *conn)
 203 {
 204         struct rds_iw_connection *ic = conn->c_transport_data;
 205
 206         /* conn was previously on the nodev_conns_list */
 207         spin_lock_irq(&iw_nodev_conns_lock);
 208         BUG_ON(list_empty(&iw_nodev_conns));
 209         BUG_ON(list_empty(&ic->iw_node));
 210         list_del(&ic->iw_node);
 211
 212         spin_lock(&rds_iwdev->spinlock);
 213         list_add_tail(&ic->iw_node, &rds_iwdev->conn_list);
 214         spin_unlock(&rds_iwdev->spinlock);
 215         spin_unlock_irq(&iw_nodev_conns_lock);
 216
 217         ic->rds_iwdev = rds_iwdev;
 218 }
 219
 220 void rds_iw_remove_conn(struct rds_iw_device *rds_iwdev, struct rds_connection *conn)
 221 {
 222         struct rds_iw_connection *ic = conn->c_transport_data;
 223
 224         /* place conn on nodev_conns_list */
 225         spin_lock(&iw_nodev_conns_lock);
 226
 227         spin_lock_irq(&rds_iwdev->spinlock);
 228         BUG_ON(list_empty(&ic->iw_node));
 229         list_del(&ic->iw_node);
 230         spin_unlock_irq(&rds_iwdev->spinlock);
 231
 232         list_add_tail(&ic->iw_node, &iw_nodev_conns);
 233
 234         spin_unlock(&iw_nodev_conns_lock);
 235
 236         rds_iw_remove_cm_id(ic->rds_iwdev, ic->i_cm_id);
 237         ic->rds_iwdev = NULL;
 238 }
 239
 240 void __rds_iw_destroy_conns(struct list_head *list, spinlock_t *list_lock)
 241 {
 242         struct rds_iw_connection *ic, *_ic;
 243         LIST_HEAD(tmp_list);
 244
 245         /* avoid calling conn_destroy with irqs off */
 246         spin_lock_irq(list_lock);
 247         list_splice(list, &tmp_list);
 248         INIT_LIST_HEAD(list);
 249         spin_unlock_irq(list_lock);
 250
 251         list_for_each_entry_safe(ic, _ic, &tmp_list, iw_node)
 252                 rds_conn_destroy(ic->conn);
 253 }
 254
 255 static void rds_iw_set_scatterlist(struct rds_iw_scatterlist *sg,
 256                 struct scatterlist *list, unsigned int sg_len)
 257 {
 258         sg->list = list;
 259         sg->len = sg_len;
 260         sg->dma_len = 0;
 261         sg->dma_npages = 0;
 262         sg->bytes = 0;
 263 }
 264
 265 static u64 *rds_iw_map_scatterlist(struct rds_iw_device *rds_iwdev,
 266                         struct rds_iw_scatterlist *sg)
 267 {
 268         struct ib_device *dev = rds_iwdev->dev;
 269         u64 *dma_pages = NULL;
 270         int i, j, ret;
 271
 272         WARN_ON(sg->dma_len);
 273
 274         sg->dma_len = ib_dma_map_sg(dev, sg->list, sg->len, DMA_BIDIRECTIONAL);
 275         if (unlikely(!sg->dma_len)) {
 276                 printk(KERN_WARNING "RDS/IW: dma_map_sg failed!\n");
 277                 return ERR_PTR(-EBUSY);
 278         }
 279
 280         sg->bytes = 0;
 281         sg->dma_npages = 0;
 282
 283         ret = -EINVAL;
 284         for (i = 0; i < sg->dma_len; ++i) {
 285                 unsigned int dma_len = ib_sg_dma_len(dev, &sg->list[i]);
 286                 u64 dma_addr = ib_sg_dma_address(dev, &sg->list[i]);
 287                 u64 end_addr;
 288
 289                 sg->bytes += dma_len;
 290
 291                 end_addr = dma_addr + dma_len;
 292                 if (dma_addr & PAGE_MASK) {
 293                         if (i > 0)
 294                                 goto out_unmap;
 295                         dma_addr &= ~PAGE_MASK;
 296                 }
 297                 if (end_addr & PAGE_MASK) {
 298                         if (i < sg->dma_len - 1)
 299                                 goto out_unmap;
 300                         end_addr = (end_addr + PAGE_MASK) & ~PAGE_MASK;
 301                 }
 302
 303                 sg->dma_npages += (end_addr - dma_addr) >> PAGE_SHIFT;
 304         }
 305
 306         /* Now gather the dma addrs into one list */
 307         if (sg->dma_npages > fastreg_message_size)
 308                 goto out_unmap;
 309
 310         dma_pages = kmalloc(sizeof(u64) * sg->dma_npages, GFP_ATOMIC);
 311         if (!dma_pages) {
 312                 ret = -ENOMEM;
 313                 goto out_unmap;
 314         }
 315
 316         for (i = j = 0; i < sg->dma_len; ++i) {
 317                 unsigned int dma_len = ib_sg_dma_len(dev, &sg->list[i]);
 318                 u64 dma_addr = ib_sg_dma_address(dev, &sg->list[i]);
 319                 u64 end_addr;
 320
 321                 end_addr = dma_addr + dma_len;
 322                 dma_addr &= ~PAGE_MASK;
 323                 for (; dma_addr < end_addr; dma_addr += PAGE_SIZE)
 324                         dma_pages[j++] = dma_addr;
 325                 BUG_ON(j > sg->dma_npages);
 326         }
 327
 328         return dma_pages;
 329
 330 out_unmap:
 331         ib_dma_unmap_sg(rds_iwdev->dev, sg->list, sg->len, DMA_BIDIRECTIONAL);
 332         sg->dma_len = 0;
 333         kfree(dma_pages);
 334         return ERR_PTR(ret);
 335 }
 336
 337
 338 struct rds_iw_mr_pool *rds_iw_create_mr_pool(struct rds_iw_device *rds_iwdev)
 339 {
 340         struct rds_iw_mr_pool *pool;
 341
 342         pool = kzalloc(sizeof(*pool), GFP_KERNEL);
 343         if (!pool) {
 344                 printk(KERN_WARNING "RDS/IW: rds_iw_create_mr_pool alloc error\n");
 345                 return ERR_PTR(-ENOMEM);
 346         }
 347
 348         pool->device = rds_iwdev;
 349         INIT_LIST_HEAD(&pool->dirty_list);
 350         INIT_LIST_HEAD(&pool->clean_list);
 351         mutex_init(&pool->flush_lock);
 352         spin_lock_init(&pool->list_lock);
 353         INIT_WORK(&pool->flush_worker, rds_iw_mr_pool_flush_worker);
 354
 355         pool->max_message_size = fastreg_message_size;
 356         pool->max_items = fastreg_pool_size;
 357         pool->max_free_pinned = pool->max_items * pool->max_message_size / 4;
 358         pool->max_pages = fastreg_message_size;
 359
 360         /* We never allow more than max_items MRs to be allocated.
 361          * When we exceed more than max_items_soft, we start freeing
 362          * items more aggressively.
 363          * Make sure that max_items > max_items_soft > max_items / 2
 364          */
 365         pool->max_items_soft = pool->max_items * 3 / 4;
 366
 367         return pool;
 368 }
 369
 370 void rds_iw_get_mr_info(struct rds_iw_device *rds_iwdev, struct rds_info_rdma_connection *iinfo)
 371 {
 372         struct rds_iw_mr_pool *pool = rds_iwdev->mr_pool;
 373
 374         iinfo->rdma_mr_max = pool->max_items;
 375         iinfo->rdma_mr_size = pool->max_pages;
 376 }
 377
 378 void rds_iw_destroy_mr_pool(struct rds_iw_mr_pool *pool)
 379 {
 380         flush_workqueue(rds_wq);
 381         rds_iw_flush_mr_pool(pool, 1);
 382         BUG_ON(atomic_read(&pool->item_count));
 383         BUG_ON(atomic_read(&pool->free_pinned));
 384         kfree(pool);
 385 }
 386
 387 static inline struct rds_iw_mr *rds_iw_reuse_fmr(struct rds_iw_mr_pool *pool)
 388 {
 389         struct rds_iw_mr *ibmr = NULL;
 390         unsigned long flags;
 391
 392         spin_lock_irqsave(&pool->list_lock, flags);
 393         if (!list_empty(&pool->clean_list)) {
 394                 ibmr = list_entry(pool->clean_list.next, struct rds_iw_mr, mapping.m_list);
 395                 list_del_init(&ibmr->mapping.m_list);
 396         }
 397         spin_unlock_irqrestore(&pool->list_lock, flags);
 398
 399         return ibmr;
 400 }
 401
 402 static struct rds_iw_mr *rds_iw_alloc_mr(struct rds_iw_device *rds_iwdev)
 403 {
 404         struct rds_iw_mr_pool *pool = rds_iwdev->mr_pool;
 405         struct rds_iw_mr *ibmr = NULL;
 406         int err = 0, iter = 0;
 407
 408         while (1) {
 409                 ibmr = rds_iw_reuse_fmr(pool);
 410                 if (ibmr)
 411                         return ibmr;
 412
 413                 /* No clean MRs - now we have the choice of either
 414                  * allocating a fresh MR up to the limit imposed by the
 415                  * driver, or flush any dirty unused MRs.
 416                  * We try to avoid stalling in the send path if possible,
 417                  * so we allocate as long as we're allowed to.
 418                  *
 419                  * We're fussy with enforcing the FMR limit, though. If the driver
 420                  * tells us we can't use more than N fmrs, we shouldn't start
 421                  * arguing with it */
 422                 if (atomic_inc_return(&pool->item_count) <= pool->max_items)
 423                         break;
 424
 425                 atomic_dec(&pool->item_count);
 426
 427                 if (++iter > 2) {
 428                         rds_iw_stats_inc(s_iw_rdma_mr_pool_depleted);
 429                         return ERR_PTR(-EAGAIN);
 430                 }
 431
 432                 /* We do have some empty MRs. Flush them out. */
 433                 rds_iw_stats_inc(s_iw_rdma_mr_pool_wait);
 434                 rds_iw_flush_mr_pool(pool, 0);
 435         }
 436
 437         ibmr = kzalloc(sizeof(*ibmr), GFP_KERNEL);
 438         if (!ibmr) {
 439                 err = -ENOMEM;
 440                 goto out_no_cigar;
 441         }
 442
 443         spin_lock_init(&ibmr->mapping.m_lock);
 444         INIT_LIST_HEAD(&ibmr->mapping.m_list);
 445         ibmr->mapping.m_mr = ibmr;
 446
 447         err = rds_iw_init_fastreg(pool, ibmr);
 448         if (err)
 449                 goto out_no_cigar;
 450
 451         rds_iw_stats_inc(s_iw_rdma_mr_alloc);
 452         return ibmr;
 453
 454 out_no_cigar:
 455         if (ibmr) {
 456                 rds_iw_destroy_fastreg(pool, ibmr);
 457                 kfree(ibmr);
 458         }
 459         atomic_dec(&pool->item_count);
 460         return ERR_PTR(err);
 461 }
 462
 463 void rds_iw_sync_mr(void *trans_private, int direction)
 464 {
 465         struct rds_iw_mr *ibmr = trans_private;
 466         struct rds_iw_device *rds_iwdev = ibmr->device;
 467
 468         switch (direction) {
 469         case DMA_FROM_DEVICE:
 470                 ib_dma_sync_sg_for_cpu(rds_iwdev->dev, ibmr->mapping.m_sg.list,
 471                         ibmr->mapping.m_sg.dma_len, DMA_BIDIRECTIONAL);
 472                 break;
 473         case DMA_TO_DEVICE:
 474                 ib_dma_sync_sg_for_device(rds_iwdev->dev, ibmr->mapping.m_sg.list,
 475                         ibmr->mapping.m_sg.dma_len, DMA_BIDIRECTIONAL);
 476                 break;
 477         }
 478 }
 479
 480 static inline unsigned int rds_iw_flush_goal(struct rds_iw_mr_pool *pool, int free_all)
 481 {
 482         unsigned int item_count;
 483
 484         item_count = atomic_read(&pool->item_count);
 485         if (free_all)
 486                 return item_count;
 487
 488         return 0;
 489 }
 490
 491 /*
 492  * Flush our pool of MRs.
 493  * At a minimum, all currently unused MRs are unmapped.
 494  * If the number of MRs allocated exceeds the limit, we also try
 495  * to free as many MRs as needed to get back to this limit.
 496  */
 497 static int rds_iw_flush_mr_pool(struct rds_iw_mr_pool *pool, int free_all)
 498 {
 499         struct rds_iw_mr *ibmr, *next;
 500         LIST_HEAD(unmap_list);
 501         LIST_HEAD(kill_list);
 502         unsigned long flags;
 503         unsigned int nfreed = 0, ncleaned = 0, unpinned = 0, free_goal;
 504         int ret = 0;
 505
 506         rds_iw_stats_inc(s_iw_rdma_mr_pool_flush);
 507
 508         mutex_lock(&pool->flush_lock);
 509
 510         spin_lock_irqsave(&pool->list_lock, flags);
 511         /* Get the list of all mappings to be destroyed */
 512         list_splice_init(&pool->dirty_list, &unmap_list);
 513         if (free_all)
 514                 list_splice_init(&pool->clean_list, &kill_list);
 515         spin_unlock_irqrestore(&pool->list_lock, flags);
 516
 517         free_goal = rds_iw_flush_goal(pool, free_all);
 518
 519         /* Batched invalidate of dirty MRs.
 520          * For FMR based MRs, the mappings on the unmap list are
 521          * actually members of an ibmr (ibmr->mapping). They either
 522          * migrate to the kill_list, or have been cleaned and should be
 523          * moved to the clean_list.
 524          * For fastregs, they will be dynamically allocated, and
 525          * will be destroyed by the unmap function.
 526          */
 527         if (!list_empty(&unmap_list)) {
 528                 ncleaned = rds_iw_unmap_fastreg_list(pool, &unmap_list,
 529                                                      &kill_list, &unpinned);
 530                 /* If we've been asked to destroy all MRs, move those
 531                  * that were simply cleaned to the kill list */
 532                 if (free_all)
 533                         list_splice_init(&unmap_list, &kill_list);
 534         }
 535
 536         /* Destroy any MRs that are past their best before date */
 537         list_for_each_entry_safe(ibmr, next, &kill_list, mapping.m_list) {
 538                 rds_iw_stats_inc(s_iw_rdma_mr_free);
 539                 list_del(&ibmr->mapping.m_list);
 540                 rds_iw_destroy_fastreg(pool, ibmr);
 541                 kfree(ibmr);
 542                 nfreed++;
 543         }
 544
 545         /* Anything that remains are laundered ibmrs, which we can add
 546          * back to the clean list. */
 547         if (!list_empty(&unmap_list)) {
 548                 spin_lock_irqsave(&pool->list_lock, flags);
 549                 list_splice(&unmap_list, &pool->clean_list);
 550                 spin_unlock_irqrestore(&pool->list_lock, flags);
 551         }
 552
 553         atomic_sub(unpinned, &pool->free_pinned);
 554         atomic_sub(ncleaned, &pool->dirty_count);
 555         atomic_sub(nfreed, &pool->item_count);
 556
 557         mutex_unlock(&pool->flush_lock);
 558         return ret;
 559 }
 560
 561 static void rds_iw_mr_pool_flush_worker(struct work_struct *work)
 562 {
 563         struct rds_iw_mr_pool *pool = container_of(work, struct rds_iw_mr_pool, flush_worker);
 564
 565         rds_iw_flush_mr_pool(pool, 0);
 566 }
 567
 568 void rds_iw_free_mr(void *trans_private, int invalidate)
 569 {
 570         struct rds_iw_mr *ibmr = trans_private;
 571         struct rds_iw_mr_pool *pool = ibmr->device->mr_pool;
 572
 573         rdsdebug("RDS/IW: free_mr nents %u\n", ibmr->mapping.m_sg.len);
 574         if (!pool)
 575                 return;
 576
 577         /* Return it to the pool's free list */
 578         rds_iw_free_fastreg(pool, ibmr);
 579
 580         /* If we've pinned too many pages, request a flush */
 581         if (atomic_read(&pool->free_pinned) >= pool->max_free_pinned ||
 582             atomic_read(&pool->dirty_count) >= pool->max_items / 10)
 583                 queue_work(rds_wq, &pool->flush_worker);
 584
 585         if (invalidate) {
 586                 if (likely(!in_interrupt())) {
 587                         rds_iw_flush_mr_pool(pool, 0);
 588                 } else {
 589                         /* We get here if the user created a MR marked
 590                          * as use_once and invalidate at the same time. */
 591                         queue_work(rds_wq, &pool->flush_worker);
 592                 }
 593         }
 594 }
 595
 596 void rds_iw_flush_mrs(void)
 597 {
 598         struct rds_iw_device *rds_iwdev;
 599
 600         list_for_each_entry(rds_iwdev, &rds_iw_devices, list) {
 601                 struct rds_iw_mr_pool *pool = rds_iwdev->mr_pool;
 602
 603                 if (pool)
 604                         rds_iw_flush_mr_pool(pool, 0);
 605         }
 606 }
 607
 608 void *rds_iw_get_mr(struct scatterlist *sg, unsigned long nents,
 609                     struct rds_sock *rs, u32 *key_ret)
 610 {
 611         struct rds_iw_device *rds_iwdev;
 612         struct rds_iw_mr *ibmr = NULL;
 613         struct rdma_cm_id *cm_id;
 614         int ret;
 615
 616         ret = rds_iw_get_device(rs, &rds_iwdev, &cm_id);
 617         if (ret || !cm_id) {
 618                 ret = -ENODEV;
 619                 goto out;
 620         }
 621
 622         if (!rds_iwdev->mr_pool) {
 623                 ret = -ENODEV;
 624                 goto out;
 625         }
 626
 627         ibmr = rds_iw_alloc_mr(rds_iwdev);
 628         if (IS_ERR(ibmr))
 629                 return ibmr;
 630
 631         ibmr->cm_id = cm_id;
 632         ibmr->device = rds_iwdev;
 633
 634         ret = rds_iw_map_fastreg(rds_iwdev->mr_pool, ibmr, sg, nents);
 635         if (ret == 0)
 636                 *key_ret = ibmr->mr->rkey;
 637         else
 638                 printk(KERN_WARNING "RDS/IW: failed to map mr (errno=%d)\n", ret);
 639
 640 out:
 641         if (ret) {
 642                 if (ibmr)
 643                         rds_iw_free_mr(ibmr, 0);
 644                 ibmr = ERR_PTR(ret);
 645         }
 646         return ibmr;
 647 }
 648
 649 /*
 650  * iWARP fastreg handling
 651  *
 652  * The life cycle of a fastreg registration is a bit different from
 653  * FMRs.
 654  * The idea behind fastreg is to have one MR, to which we bind different
 655  * mappings over time. To avoid stalling on the expensive map and invalidate
 656  * operations, these operations are pipelined on the same send queue on
 657  * which we want to send the message containing the r_key.
 658  *
 659  * This creates a bit of a problem for us, as we do not have the destination
 660  * IP in GET_MR, so the connection must be setup prior to the GET_MR call for
 661  * RDMA to be correctly setup.  If a fastreg request is present, rds_iw_xmit
 662  * will try to queue a LOCAL_INV (if needed) and a FAST_REG_MR work request
 663  * before queuing the SEND. When completions for these arrive, they are
 664  * dispatched to the MR has a bit set showing that RDMa can be performed.
 665  *
 666  * There is another interesting aspect that's related to invalidation.
 667  * The application can request that a mapping is invalidated in FREE_MR.
 668  * The expectation there is that this invalidation step includes ALL
 669  * PREVIOUSLY FREED MRs.
 670  */
 671 static int rds_iw_init_fastreg(struct rds_iw_mr_pool *pool,
 672                                 struct rds_iw_mr *ibmr)
 673 {
 674         struct rds_iw_device *rds_iwdev = pool->device;
 675         struct ib_fast_reg_page_list *page_list = NULL;
 676         struct ib_mr *mr;
 677         int err;
 678
 679         mr = ib_alloc_fast_reg_mr(rds_iwdev->pd, pool->max_message_size);
 680         if (IS_ERR(mr)) {
 681                 err = PTR_ERR(mr);
 682
 683                 printk(KERN_WARNING "RDS/IW: ib_alloc_fast_reg_mr failed (err=%d)\n", err);
 684                 return err;
 685         }
 686
 687         /* FIXME - this is overkill, but mapping->m_sg.dma_len/mapping->m_sg.dma_npages
 688          * is not filled in.
 689          */
 690         page_list = ib_alloc_fast_reg_page_list(rds_iwdev->dev, pool->max_message_size);
 691         if (IS_ERR(page_list)) {
 692                 err = PTR_ERR(page_list);
 693
 694                 printk(KERN_WARNING "RDS/IW: ib_alloc_fast_reg_page_list failed (err=%d)\n", err);
 695                 ib_dereg_mr(mr);
 696                 return err;
 697         }
 698
 699         ibmr->page_list = page_list;
 700         ibmr->mr = mr;
 701         return 0;
 702 }
 703
 704 static int rds_iw_rdma_build_fastreg(struct rds_iw_mapping *mapping)
 705 {
 706         struct rds_iw_mr *ibmr = mapping->m_mr;
 707         struct ib_send_wr f_wr, *failed_wr;
 708         int ret;
 709
 710         /*
 711          * Perform a WR for the fast_reg_mr. Each individual page
 712          * in the sg list is added to the fast reg page list and placed
 713          * inside the fast_reg_mr WR.  The key used is a rolling 8bit
 714          * counter, which should guarantee uniqueness.
 715          */
 716         ib_update_fast_reg_key(ibmr->mr, ibmr->remap_count++);
 717         mapping->m_rkey = ibmr->mr->rkey;
 718
 719         memset(&f_wr, 0, sizeof(f_wr));
 720         f_wr.wr_id = RDS_IW_FAST_REG_WR_ID;
 721         f_wr.opcode = IB_WR_FAST_REG_MR;
 722         f_wr.wr.fast_reg.length = mapping->m_sg.bytes;
 723         f_wr.wr.fast_reg.rkey = mapping->m_rkey;
 724         f_wr.wr.fast_reg.page_list = ibmr->page_list;
 725         f_wr.wr.fast_reg.page_list_len = mapping->m_sg.dma_len;
 726         f_wr.wr.fast_reg.page_shift = PAGE_SHIFT;
 727         f_wr.wr.fast_reg.access_flags = IB_ACCESS_LOCAL_WRITE |
 728                                 IB_ACCESS_REMOTE_READ |
 729                                 IB_ACCESS_REMOTE_WRITE;
 730         f_wr.wr.fast_reg.iova_start = 0;
 731         f_wr.send_flags = IB_SEND_SIGNALED;
 732
 733         failed_wr = &f_wr;
 734         ret = ib_post_send(ibmr->cm_id->qp, &f_wr, &failed_wr);
 735         BUG_ON(failed_wr != &f_wr);
 736         if (ret)
 737                 printk_ratelimited(KERN_WARNING "RDS/IW: %s:%d ib_post_send returned %d\n",
 738                         __func__, __LINE__, ret);
 739         return ret;
 740 }
 741
 742 static int rds_iw_rdma_fastreg_inv(struct rds_iw_mr *ibmr)
 743 {
 744         struct ib_send_wr s_wr, *failed_wr;
 745         int ret = 0;
 746
 747         if (!ibmr->cm_id->qp || !ibmr->mr)
 748                 goto out;
 749
 750         memset(&s_wr, 0, sizeof(s_wr));
 751         s_wr.wr_id = RDS_IW_LOCAL_INV_WR_ID;
 752         s_wr.opcode = IB_WR_LOCAL_INV;
 753         s_wr.ex.invalidate_rkey = ibmr->mr->rkey;
 754         s_wr.send_flags = IB_SEND_SIGNALED;
 755
 756         failed_wr = &s_wr;
 757         ret = ib_post_send(ibmr->cm_id->qp, &s_wr, &failed_wr);
 758         if (ret) {
 759                 printk_ratelimited(KERN_WARNING "RDS/IW: %s:%d ib_post_send returned %d\n",
 760                         __func__, __LINE__, ret);
 761                 goto out;
 762         }
 763 out:
 764         return ret;
 765 }
 766
 767 static int rds_iw_map_fastreg(struct rds_iw_mr_pool *pool,
 768                         struct rds_iw_mr *ibmr,
 769                         struct scatterlist *sg,
 770                         unsigned int sg_len)
 771 {
 772         struct rds_iw_device *rds_iwdev = pool->device;
 773         struct rds_iw_mapping *mapping = &ibmr->mapping;
 774         u64 *dma_pages;
 775         int i, ret = 0;
 776
 777         rds_iw_set_scatterlist(&mapping->m_sg, sg, sg_len);
 778
 779         dma_pages = rds_iw_map_scatterlist(rds_iwdev, &mapping->m_sg);
 780         if (IS_ERR(dma_pages)) {
 781                 ret = PTR_ERR(dma_pages);
 782                 dma_pages = NULL;
 783                 goto out;
 784         }
 785
 786         if (mapping->m_sg.dma_len > pool->max_message_size) {
 787                 ret = -EMSGSIZE;
 788                 goto out;
 789         }
 790
 791         for (i = 0; i < mapping->m_sg.dma_npages; ++i)
 792                 ibmr->page_list->page_list[i] = dma_pages[i];
 793
 794         ret = rds_iw_rdma_build_fastreg(mapping);
 795         if (ret)
 796                 goto out;
 797
 798         rds_iw_stats_inc(s_iw_rdma_mr_used);
 799
 800 out:
 801         kfree(dma_pages);
 802
 803         return ret;
 804 }
 805
 806 /*
 807  * "Free" a fastreg MR.
 808  */
 809 static void rds_iw_free_fastreg(struct rds_iw_mr_pool *pool,
 810                 struct rds_iw_mr *ibmr)
 811 {
 812         unsigned long flags;
 813         int ret;
 814
 815         if (!ibmr->mapping.m_sg.dma_len)
 816                 return;
 817
 818         ret = rds_iw_rdma_fastreg_inv(ibmr);
 819         if (ret)
 820                 return;
 821
 822         /* Try to post the LOCAL_INV WR to the queue. */
 823         spin_lock_irqsave(&pool->list_lock, flags);
 824
 825         list_add_tail(&ibmr->mapping.m_list, &pool->dirty_list);
 826         atomic_add(ibmr->mapping.m_sg.len, &pool->free_pinned);
 827         atomic_inc(&pool->dirty_count);
 828
 829         spin_unlock_irqrestore(&pool->list_lock, flags);
 830 }
 831
 832 static unsigned int rds_iw_unmap_fastreg_list(struct rds_iw_mr_pool *pool,
 833                                 struct list_head *unmap_list,
 834                                 struct list_head *kill_list,
 835                                 int *unpinned)
 836 {
 837         struct rds_iw_mapping *mapping, *next;
 838         unsigned int ncleaned = 0;
 839         LIST_HEAD(laundered);
 840
 841         /* Batched invalidation of fastreg MRs.
 842          * Why do we do it this way, even though we could pipeline unmap
 843          * and remap? The reason is the application semantics - when the
 844          * application requests an invalidation of MRs, it expects all
 845          * previously released R_Keys to become invalid.
 846          *
 847          * If we implement MR reuse naively, we risk memory corruption
 848          * (this has actually been observed). So the default behavior
 849          * requires that a MR goes through an explicit unmap operation before
 850          * we can reuse it again.
 851          *
 852          * We could probably improve on this a little, by allowing immediate
 853          * reuse of a MR on the same socket (eg you could add small
 854          * cache of unused MRs to strct rds_socket - GET_MR could grab one
 855          * of these without requiring an explicit invalidate).
 856          */
 857         while (!list_empty(unmap_list)) {
 858                 unsigned long flags;
 859
 860                 spin_lock_irqsave(&pool->list_lock, flags);
 861                 list_for_each_entry_safe(mapping, next, unmap_list, m_list) {
 862                         *unpinned += mapping->m_sg.len;
 863                         list_move(&mapping->m_list, &laundered);
 864                         ncleaned++;
 865                 }
 866                 spin_unlock_irqrestore(&pool->list_lock, flags);
 867         }
 868
 869         /* Move all laundered mappings back to the unmap list.
 870          * We do not kill any WRs right now - it doesn't seem the
 871          * fastreg API has a max_remap limit. */
 872         list_splice_init(&laundered, unmap_list);
 873
 874         return ncleaned;
 875 }
 876
 877 static void rds_iw_destroy_fastreg(struct rds_iw_mr_pool *pool,
 878                 struct rds_iw_mr *ibmr)
 879 {
 880         if (ibmr->page_list)
 881                 ib_free_fast_reg_page_list(ibmr->page_list);
 882         if (ibmr->mr)
 883                 ib_dereg_mr(ibmr->mr);
 884 }