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
  35 #include "rds.h"
  36 #include "rdma.h"
  37 #include "iw.h"
  38
  39
  40 /*
  41  * This is stored as mr->r_trans_private.
  42  */
  43 struct rds_iw_mr {
  44         struct rds_iw_device    *device;
  45         struct rds_iw_mr_pool   *pool;
  46         struct rdma_cm_id       *cm_id;
  47
  48         struct ib_mr    *mr;
  49         struct ib_fast_reg_page_list *page_list;
  50
  51         struct rds_iw_mapping   mapping;
  52         unsigned char           remap_count;
  53 };
  54
  55 /*
  56  * Our own little MR pool
  57  */
  58 struct rds_iw_mr_pool {
  59         struct rds_iw_device    *device;                /* back ptr to the device that owns us */
  60
  61         struct mutex            flush_lock;             /* serialize fmr invalidate */
  62         struct work_struct      flush_worker;           /* flush worker */
  63
  64         spinlock_t              list_lock;              /* protect variables below */
  65         atomic_t                item_count;             /* total # of MRs */
  66         atomic_t                dirty_count;            /* # dirty of MRs */
  67         struct list_head        dirty_list;             /* dirty mappings */
  68         struct list_head        clean_list;             /* unused & unamapped MRs */
  69         atomic_t                free_pinned;            /* memory pinned by free MRs */
  70         unsigned long           max_message_size;       /* in pages */
  71         unsigned long           max_items;
  72         unsigned long           max_items_soft;
  73         unsigned long           max_free_pinned;
  74         int                     max_pages;
  75 };
  76
  77 static int rds_iw_flush_mr_pool(struct rds_iw_mr_pool *pool, int free_all);
  78 static void rds_iw_mr_pool_flush_worker(struct work_struct *work);
  79 static int rds_iw_init_fastreg(struct rds_iw_mr_pool *pool, struct rds_iw_mr *ibmr);
  80 static int rds_iw_map_fastreg(struct rds_iw_mr_pool *pool,
  81                           struct rds_iw_mr *ibmr,
  82                           struct scatterlist *sg, unsigned int nents);
  83 static void rds_iw_free_fastreg(struct rds_iw_mr_pool *pool, struct rds_iw_mr *ibmr);
  84 static unsigned int rds_iw_unmap_fastreg_list(struct rds_iw_mr_pool *pool,
  85                         struct list_head *unmap_list,
  86                         struct list_head *kill_list);
  87 static void rds_iw_destroy_fastreg(struct rds_iw_mr_pool *pool, struct rds_iw_mr *ibmr);
  88
  89 static int rds_iw_get_device(struct rds_sock *rs, struct rds_iw_device **rds_iwdev, struct rdma_cm_id **cm_id)
  90 {
  91         struct rds_iw_device *iwdev;
  92         struct rds_iw_cm_id *i_cm_id;
  93
  94         *rds_iwdev = NULL;
  95         *cm_id = NULL;
  96
  97         list_for_each_entry(iwdev, &rds_iw_devices, list) {
  98                 spin_lock_irq(&iwdev->spinlock);
  99                 list_for_each_entry(i_cm_id, &iwdev->cm_id_list, list) {
 100                         struct sockaddr_in *src_addr, *dst_addr;
 101
 102                         src_addr = (struct sockaddr_in *)&i_cm_id->cm_id->route.addr.src_addr;
 103                         dst_addr = (struct sockaddr_in *)&i_cm_id->cm_id->route.addr.dst_addr;
 104
 105                         rdsdebug("local ipaddr = %x port %d, "
 106                                  "remote ipaddr = %x port %d"
 107                                  "..looking for %x port %d, "
 108                                  "remote ipaddr = %x port %d\n",
 109                                 src_addr->sin_addr.s_addr,
 110                                 src_addr->sin_port,
 111                                 dst_addr->sin_addr.s_addr,
 112                                 dst_addr->sin_port,
 113                                 rs->rs_bound_addr,
 114                                 rs->rs_bound_port,
 115                                 rs->rs_conn_addr,
 116                                 rs->rs_conn_port);
 117 #ifdef WORKING_TUPLE_DETECTION
 118                         if (src_addr->sin_addr.s_addr == rs->rs_bound_addr &&
 119                             src_addr->sin_port == rs->rs_bound_port &&
 120                             dst_addr->sin_addr.s_addr == rs->rs_conn_addr &&
 121                             dst_addr->sin_port == rs->rs_conn_port) {
 122 #else
 123                         /* FIXME - needs to compare the local and remote
 124                          * ipaddr/port tuple, but the ipaddr is the only
 125                          * available infomation in the rds_sock (as the rest are
 126                          * zero'ed.  It doesn't appear to be properly populated
 127                          * during connection setup...
 128                          */
 129                         if (src_addr->sin_addr.s_addr == rs->rs_bound_addr) {
 130 #endif
 131                                 spin_unlock_irq(&iwdev->spinlock);
 132                                 *rds_iwdev = iwdev;
 133                                 *cm_id = i_cm_id->cm_id;
 134                                 return 0;
 135                         }
 136                 }
 137                 spin_unlock_irq(&iwdev->spinlock);
 138         }
 139
 140         return 1;
 141 }
 142
 143 static int rds_iw_add_cm_id(struct rds_iw_device *rds_iwdev, struct rdma_cm_id *cm_id)
 144 {
 145         struct rds_iw_cm_id *i_cm_id;
 146
 147         i_cm_id = kmalloc(sizeof *i_cm_id, GFP_KERNEL);
 148         if (!i_cm_id)
 149                 return -ENOMEM;
 150
 151         i_cm_id->cm_id = cm_id;
 152
 153         spin_lock_irq(&rds_iwdev->spinlock);
 154         list_add_tail(&i_cm_id->list, &rds_iwdev->cm_id_list);
 155         spin_unlock_irq(&rds_iwdev->spinlock);
 156
 157         return 0;
 158 }
 159
 160 void rds_iw_remove_cm_id(struct rds_iw_device *rds_iwdev, struct rdma_cm_id *cm_id)
 161 {
 162         struct rds_iw_cm_id *i_cm_id;
 163
 164         spin_lock_irq(&rds_iwdev->spinlock);
 165         list_for_each_entry(i_cm_id, &rds_iwdev->cm_id_list, list) {
 166                 if (i_cm_id->cm_id == cm_id) {
 167                         list_del(&i_cm_id->list);
 168                         kfree(i_cm_id);
 169                         break;
 170                 }
 171         }
 172         spin_unlock_irq(&rds_iwdev->spinlock);
 173 }
 174
 175
 176 int rds_iw_update_cm_id(struct rds_iw_device *rds_iwdev, struct rdma_cm_id *cm_id)
 177 {
 178         struct sockaddr_in *src_addr, *dst_addr;
 179         struct rds_iw_device *rds_iwdev_old;
 180         struct rds_sock rs;
 181         struct rdma_cm_id *pcm_id;
 182         int rc;
 183
 184         src_addr = (struct sockaddr_in *)&cm_id->route.addr.src_addr;
 185         dst_addr = (struct sockaddr_in *)&cm_id->route.addr.dst_addr;
 186
 187         rs.rs_bound_addr = src_addr->sin_addr.s_addr;
 188         rs.rs_bound_port = src_addr->sin_port;
 189         rs.rs_conn_addr = dst_addr->sin_addr.s_addr;
 190         rs.rs_conn_port = dst_addr->sin_port;
 191
 192         rc = rds_iw_get_device(&rs, &rds_iwdev_old, &pcm_id);
 193         if (rc)
 194                 rds_iw_remove_cm_id(rds_iwdev, cm_id);
 195
 196         return rds_iw_add_cm_id(rds_iwdev, cm_id);
 197 }
 198
 199 void rds_iw_add_conn(struct rds_iw_device *rds_iwdev, struct rds_connection *conn)
 200 {
 201         struct rds_iw_connection *ic = conn->c_transport_data;
 202
 203         /* conn was previously on the nodev_conns_list */
 204         spin_lock_irq(&iw_nodev_conns_lock);
 205         BUG_ON(list_empty(&iw_nodev_conns));
 206         BUG_ON(list_empty(&ic->iw_node));
 207         list_del(&ic->iw_node);
 208
 209         spin_lock_irq(&rds_iwdev->spinlock);
 210         list_add_tail(&ic->iw_node, &rds_iwdev->conn_list);
 211         spin_unlock_irq(&rds_iwdev->spinlock);
 212         spin_unlock_irq(&iw_nodev_conns_lock);
 213
 214         ic->rds_iwdev = rds_iwdev;
 215 }
 216
 217 void rds_iw_remove_conn(struct rds_iw_device *rds_iwdev, struct rds_connection *conn)
 218 {
 219         struct rds_iw_connection *ic = conn->c_transport_data;
 220
 221         /* place conn on nodev_conns_list */
 222         spin_lock(&iw_nodev_conns_lock);
 223
 224         spin_lock_irq(&rds_iwdev->spinlock);
 225         BUG_ON(list_empty(&ic->iw_node));
 226         list_del(&ic->iw_node);
 227         spin_unlock_irq(&rds_iwdev->spinlock);
 228
 229         list_add_tail(&ic->iw_node, &iw_nodev_conns);
 230
 231         spin_unlock(&iw_nodev_conns_lock);
 232
 233         rds_iw_remove_cm_id(ic->rds_iwdev, ic->i_cm_id);
 234         ic->rds_iwdev = NULL;
 235 }
 236
 237 void __rds_iw_destroy_conns(struct list_head *list, spinlock_t *list_lock)
 238 {
 239         struct rds_iw_connection *ic, *_ic;
 240         LIST_HEAD(tmp_list);
 241
 242         /* avoid calling conn_destroy with irqs off */
 243         spin_lock_irq(list_lock);
 244         list_splice(list, &tmp_list);
 245         INIT_LIST_HEAD(list);
 246         spin_unlock_irq(list_lock);
 247
 248         list_for_each_entry_safe(ic, _ic, &tmp_list, iw_node) {
 249                 if (ic->conn->c_passive)
 250                         rds_conn_destroy(ic->conn->c_passive);
 251                 rds_conn_destroy(ic->conn);
 252         }
 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                         unsigned int dma_page_shift)
 268 {
 269         struct ib_device *dev = rds_iwdev->dev;
 270         u64 *dma_pages = NULL;
 271         u64 dma_mask;
 272         unsigned int dma_page_size;
 273         int i, j, ret;
 274
 275         dma_page_size = 1 << dma_page_shift;
 276         dma_mask = dma_page_size - 1;
 277
 278         WARN_ON(sg->dma_len);
 279
 280         sg->dma_len = ib_dma_map_sg(dev, sg->list, sg->len, DMA_BIDIRECTIONAL);
 281         if (unlikely(!sg->dma_len)) {
 282                 printk(KERN_WARNING "RDS/IW: dma_map_sg failed!\n");
 283                 return ERR_PTR(-EBUSY);
 284         }
 285
 286         sg->bytes = 0;
 287         sg->dma_npages = 0;
 288
 289         ret = -EINVAL;
 290         for (i = 0; i < sg->dma_len; ++i) {
 291                 unsigned int dma_len = ib_sg_dma_len(dev, &sg->list[i]);
 292                 u64 dma_addr = ib_sg_dma_address(dev, &sg->list[i]);
 293                 u64 end_addr;
 294
 295                 sg->bytes += dma_len;
 296
 297                 end_addr = dma_addr + dma_len;
 298                 if (dma_addr & dma_mask) {
 299                         if (i > 0)
 300                                 goto out_unmap;
 301                         dma_addr &= ~dma_mask;
 302                 }
 303                 if (end_addr & dma_mask) {
 304                         if (i < sg->dma_len - 1)
 305                                 goto out_unmap;
 306                         end_addr = (end_addr + dma_mask) & ~dma_mask;
 307                 }
 308
 309                 sg->dma_npages += (end_addr - dma_addr) >> dma_page_shift;
 310         }
 311
 312         /* Now gather the dma addrs into one list */
 313         if (sg->dma_npages > fastreg_message_size)
 314                 goto out_unmap;
 315
 316         dma_pages = kmalloc(sizeof(u64) * sg->dma_npages, GFP_ATOMIC);
 317         if (!dma_pages) {
 318                 ret = -ENOMEM;
 319                 goto out_unmap;
 320         }
 321
 322         for (i = j = 0; i < sg->dma_len; ++i) {
 323                 unsigned int dma_len = ib_sg_dma_len(dev, &sg->list[i]);
 324                 u64 dma_addr = ib_sg_dma_address(dev, &sg->list[i]);
 325                 u64 end_addr;
 326
 327                 end_addr = dma_addr + dma_len;
 328                 dma_addr &= ~dma_mask;
 329                 for (; dma_addr < end_addr; dma_addr += dma_page_size)
 330                         dma_pages[j++] = dma_addr;
 331                 BUG_ON(j > sg->dma_npages);
 332         }
 333
 334         return dma_pages;
 335
 336 out_unmap:
 337         ib_dma_unmap_sg(rds_iwdev->dev, sg->list, sg->len, DMA_BIDIRECTIONAL);
 338         sg->dma_len = 0;
 339         kfree(dma_pages);
 340         return ERR_PTR(ret);
 341 }
 342
 343
 344 struct rds_iw_mr_pool *rds_iw_create_mr_pool(struct rds_iw_device *rds_iwdev)
 345 {
 346         struct rds_iw_mr_pool *pool;
 347
 348         pool = kzalloc(sizeof(*pool), GFP_KERNEL);
 349         if (!pool) {
 350                 printk(KERN_WARNING "RDS/IW: rds_iw_create_mr_pool alloc error\n");
 351                 return ERR_PTR(-ENOMEM);
 352         }
 353
 354         pool->device = rds_iwdev;
 355         INIT_LIST_HEAD(&pool->dirty_list);
 356         INIT_LIST_HEAD(&pool->clean_list);
 357         mutex_init(&pool->flush_lock);
 358         spin_lock_init(&pool->list_lock);
 359         INIT_WORK(&pool->flush_worker, rds_iw_mr_pool_flush_worker);
 360
 361         pool->max_message_size = fastreg_message_size;
 362         pool->max_items = fastreg_pool_size;
 363         pool->max_free_pinned = pool->max_items * pool->max_message_size / 4;
 364         pool->max_pages = fastreg_message_size;
 365
 366         /* We never allow more than max_items MRs to be allocated.
 367          * When we exceed more than max_items_soft, we start freeing
 368          * items more aggressively.
 369          * Make sure that max_items > max_items_soft > max_items / 2
 370          */
 371         pool->max_items_soft = pool->max_items * 3 / 4;
 372
 373         return pool;
 374 }
 375
 376 void rds_iw_get_mr_info(struct rds_iw_device *rds_iwdev, struct rds_info_rdma_connection *iinfo)
 377 {
 378         struct rds_iw_mr_pool *pool = rds_iwdev->mr_pool;
 379
 380         iinfo->rdma_mr_max = pool->max_items;
 381         iinfo->rdma_mr_size = pool->max_pages;
 382 }
 383
 384 void rds_iw_destroy_mr_pool(struct rds_iw_mr_pool *pool)
 385 {
 386         flush_workqueue(rds_wq);
 387         rds_iw_flush_mr_pool(pool, 1);
 388         BUG_ON(atomic_read(&pool->item_count));
 389         BUG_ON(atomic_read(&pool->free_pinned));
 390         kfree(pool);
 391 }
 392
 393 static inline struct rds_iw_mr *rds_iw_reuse_fmr(struct rds_iw_mr_pool *pool)
 394 {
 395         struct rds_iw_mr *ibmr = NULL;
 396         unsigned long flags;
 397
 398         spin_lock_irqsave(&pool->list_lock, flags);
 399         if (!list_empty(&pool->clean_list)) {
 400                 ibmr = list_entry(pool->clean_list.next, struct rds_iw_mr, mapping.m_list);
 401                 list_del_init(&ibmr->mapping.m_list);
 402         }
 403         spin_unlock_irqrestore(&pool->list_lock, flags);
 404
 405         return ibmr;
 406 }
 407
 408 static struct rds_iw_mr *rds_iw_alloc_mr(struct rds_iw_device *rds_iwdev)
 409 {
 410         struct rds_iw_mr_pool *pool = rds_iwdev->mr_pool;
 411         struct rds_iw_mr *ibmr = NULL;
 412         int err = 0, iter = 0;
 413
 414         while (1) {
 415                 ibmr = rds_iw_reuse_fmr(pool);
 416                 if (ibmr)
 417                         return ibmr;
 418
 419                 /* No clean MRs - now we have the choice of either
 420                  * allocating a fresh MR up to the limit imposed by the
 421                  * driver, or flush any dirty unused MRs.
 422                  * We try to avoid stalling in the send path if possible,
 423                  * so we allocate as long as we're allowed to.
 424                  *
 425                  * We're fussy with enforcing the FMR limit, though. If the driver
 426                  * tells us we can't use more than N fmrs, we shouldn't start
 427                  * arguing with it */
 428                 if (atomic_inc_return(&pool->item_count) <= pool->max_items)
 429                         break;
 430
 431                 atomic_dec(&pool->item_count);
 432
 433                 if (++iter > 2) {
 434                         rds_iw_stats_inc(s_iw_rdma_mr_pool_depleted);
 435                         return ERR_PTR(-EAGAIN);
 436                 }
 437
 438                 /* We do have some empty MRs. Flush them out. */
 439                 rds_iw_stats_inc(s_iw_rdma_mr_pool_wait);
 440                 rds_iw_flush_mr_pool(pool, 0);
 441         }
 442
 443         ibmr = kzalloc(sizeof(*ibmr), GFP_KERNEL);
 444         if (!ibmr) {
 445                 err = -ENOMEM;
 446                 goto out_no_cigar;
 447         }
 448
 449         spin_lock_init(&ibmr->mapping.m_lock);
 450         INIT_LIST_HEAD(&ibmr->mapping.m_list);
 451         ibmr->mapping.m_mr = ibmr;
 452
 453         err = rds_iw_init_fastreg(pool, ibmr);
 454         if (err)
 455                 goto out_no_cigar;
 456
 457         rds_iw_stats_inc(s_iw_rdma_mr_alloc);
 458         return ibmr;
 459
 460 out_no_cigar:
 461         if (ibmr) {
 462                 rds_iw_destroy_fastreg(pool, ibmr);
 463                 kfree(ibmr);
 464         }
 465         atomic_dec(&pool->item_count);
 466         return ERR_PTR(err);
 467 }
 468
 469 void rds_iw_sync_mr(void *trans_private, int direction)
 470 {
 471         struct rds_iw_mr *ibmr = trans_private;
 472         struct rds_iw_device *rds_iwdev = ibmr->device;
 473
 474         switch (direction) {
 475         case DMA_FROM_DEVICE:
 476                 ib_dma_sync_sg_for_cpu(rds_iwdev->dev, ibmr->mapping.m_sg.list,
 477                         ibmr->mapping.m_sg.dma_len, DMA_BIDIRECTIONAL);
 478                 break;
 479         case DMA_TO_DEVICE:
 480                 ib_dma_sync_sg_for_device(rds_iwdev->dev, ibmr->mapping.m_sg.list,
 481                         ibmr->mapping.m_sg.dma_len, DMA_BIDIRECTIONAL);
 482                 break;
 483         }
 484 }
 485
 486 static inline unsigned int rds_iw_flush_goal(struct rds_iw_mr_pool *pool, int free_all)
 487 {
 488         unsigned int item_count;
 489
 490         item_count = atomic_read(&pool->item_count);
 491         if (free_all)
 492                 return item_count;
 493
 494         return 0;
 495 }
 496
 497 /*
 498  * Flush our pool of MRs.
 499  * At a minimum, all currently unused MRs are unmapped.
 500  * If the number of MRs allocated exceeds the limit, we also try
 501  * to free as many MRs as needed to get back to this limit.
 502  */
 503 static int rds_iw_flush_mr_pool(struct rds_iw_mr_pool *pool, int free_all)
 504 {
 505         struct rds_iw_mr *ibmr, *next;
 506         LIST_HEAD(unmap_list);
 507         LIST_HEAD(kill_list);
 508         unsigned long flags;
 509         unsigned int nfreed = 0, ncleaned = 0, free_goal;
 510         int ret = 0;
 511
 512         rds_iw_stats_inc(s_iw_rdma_mr_pool_flush);
 513
 514         mutex_lock(&pool->flush_lock);
 515
 516         spin_lock_irqsave(&pool->list_lock, flags);
 517         /* Get the list of all mappings to be destroyed */
 518         list_splice_init(&pool->dirty_list, &unmap_list);
 519         if (free_all)
 520                 list_splice_init(&pool->clean_list, &kill_list);
 521         spin_unlock_irqrestore(&pool->list_lock, flags);
 522
 523         free_goal = rds_iw_flush_goal(pool, free_all);
 524
 525         /* Batched invalidate of dirty MRs.
 526          * For FMR based MRs, the mappings on the unmap list are
 527          * actually members of an ibmr (ibmr->mapping). They either
 528          * migrate to the kill_list, or have been cleaned and should be
 529          * moved to the clean_list.
 530          * For fastregs, they will be dynamically allocated, and
 531          * will be destroyed by the unmap function.
 532          */
 533         if (!list_empty(&unmap_list)) {
 534                 ncleaned = rds_iw_unmap_fastreg_list(pool, &unmap_list, &kill_list);
 535                 /* If we've been asked to destroy all MRs, move those
 536                  * that were simply cleaned to the kill list */
 537                 if (free_all)
 538                         list_splice_init(&unmap_list, &kill_list);
 539         }
 540
 541         /* Destroy any MRs that are past their best before date */
 542         list_for_each_entry_safe(ibmr, next, &kill_list, mapping.m_list) {
 543                 rds_iw_stats_inc(s_iw_rdma_mr_free);
 544                 list_del(&ibmr->mapping.m_list);
 545                 rds_iw_destroy_fastreg(pool, ibmr);
 546                 kfree(ibmr);
 547                 nfreed++;
 548         }
 549
 550         /* Anything that remains are laundered ibmrs, which we can add
 551          * back to the clean list. */
 552         if (!list_empty(&unmap_list)) {
 553                 spin_lock_irqsave(&pool->list_lock, flags);
 554                 list_splice(&unmap_list, &pool->clean_list);
 555                 spin_unlock_irqrestore(&pool->list_lock, flags);
 556         }
 557
 558         atomic_sub(ncleaned, &pool->dirty_count);
 559         atomic_sub(nfreed, &pool->item_count);
 560
 561         mutex_unlock(&pool->flush_lock);
 562         return ret;
 563 }
 564
 565 static void rds_iw_mr_pool_flush_worker(struct work_struct *work)
 566 {
 567         struct rds_iw_mr_pool *pool = container_of(work, struct rds_iw_mr_pool, flush_worker);
 568
 569         rds_iw_flush_mr_pool(pool, 0);
 570 }
 571
 572 void rds_iw_free_mr(void *trans_private, int invalidate)
 573 {
 574         struct rds_iw_mr *ibmr = trans_private;
 575         struct rds_iw_mr_pool *pool = ibmr->device->mr_pool;
 576
 577         rdsdebug("RDS/IW: free_mr nents %u\n", ibmr->mapping.m_sg.len);
 578         if (!pool)
 579                 return;
 580
 581         /* Return it to the pool's free list */
 582         rds_iw_free_fastreg(pool, ibmr);
 583
 584         /* If we've pinned too many pages, request a flush */
 585         if (atomic_read(&pool->free_pinned) >= pool->max_free_pinned
 586          || atomic_read(&pool->dirty_count) >= pool->max_items / 10)
 587                 queue_work(rds_wq, &pool->flush_worker);
 588
 589         if (invalidate) {
 590                 if (likely(!in_interrupt())) {
 591                         rds_iw_flush_mr_pool(pool, 0);
 592                 } else {
 593                         /* We get here if the user created a MR marked
 594                          * as use_once and invalidate at the same time. */
 595                         queue_work(rds_wq, &pool->flush_worker);
 596                 }
 597         }
 598 }
 599
 600 void rds_iw_flush_mrs(void)
 601 {
 602         struct rds_iw_device *rds_iwdev;
 603
 604         list_for_each_entry(rds_iwdev, &rds_iw_devices, list) {
 605                 struct rds_iw_mr_pool *pool = rds_iwdev->mr_pool;
 606
 607                 if (pool)
 608                         rds_iw_flush_mr_pool(pool, 0);
 609         }
 610 }
 611
 612 void *rds_iw_get_mr(struct scatterlist *sg, unsigned long nents,
 613                     struct rds_sock *rs, u32 *key_ret)
 614 {
 615         struct rds_iw_device *rds_iwdev;
 616         struct rds_iw_mr *ibmr = NULL;
 617         struct rdma_cm_id *cm_id;
 618         int ret;
 619
 620         ret = rds_iw_get_device(rs, &rds_iwdev, &cm_id);
 621         if (ret || !cm_id) {
 622                 ret = -ENODEV;
 623                 goto out;
 624         }
 625
 626         if (!rds_iwdev->mr_pool) {
 627                 ret = -ENODEV;
 628                 goto out;
 629         }
 630
 631         ibmr = rds_iw_alloc_mr(rds_iwdev);
 632         if (IS_ERR(ibmr))
 633                 return ibmr;
 634
 635         ibmr->cm_id = cm_id;
 636         ibmr->device = rds_iwdev;
 637
 638         ret = rds_iw_map_fastreg(rds_iwdev->mr_pool, ibmr, sg, nents);
 639         if (ret == 0)
 640                 *key_ret = ibmr->mr->rkey;
 641         else
 642                 printk(KERN_WARNING "RDS/IW: failed to map mr (errno=%d)\n", ret);
 643
 644 out:
 645         if (ret) {
 646                 if (ibmr)
 647                         rds_iw_free_mr(ibmr, 0);
 648                 ibmr = ERR_PTR(ret);
 649         }
 650         return ibmr;
 651 }
 652
 653 /*
 654  * iWARP fastreg handling
 655  *
 656  * The life cycle of a fastreg registration is a bit different from
 657  * FMRs.
 658  * The idea behind fastreg is to have one MR, to which we bind different
 659  * mappings over time. To avoid stalling on the expensive map and invalidate
 660  * operations, these operations are pipelined on the same send queue on
 661  * which we want to send the message containing the r_key.
 662  *
 663  * This creates a bit of a problem for us, as we do not have the destination
 664  * IP in GET_MR, so the connection must be setup prior to the GET_MR call for
 665  * RDMA to be correctly setup.  If a fastreg request is present, rds_iw_xmit
 666  * will try to queue a LOCAL_INV (if needed) and a FAST_REG_MR work request
 667  * before queuing the SEND. When completions for these arrive, they are
 668  * dispatched to the MR has a bit set showing that RDMa can be performed.
 669  *
 670  * There is another interesting aspect that's related to invalidation.
 671  * The application can request that a mapping is invalidated in FREE_MR.
 672  * The expectation there is that this invalidation step includes ALL
 673  * PREVIOUSLY FREED MRs.
 674  */
 675 static int rds_iw_init_fastreg(struct rds_iw_mr_pool *pool,
 676                                 struct rds_iw_mr *ibmr)
 677 {
 678         struct rds_iw_device *rds_iwdev = pool->device;
 679         struct ib_fast_reg_page_list *page_list = NULL;
 680         struct ib_mr *mr;
 681         int err;
 682
 683         mr = ib_alloc_fast_reg_mr(rds_iwdev->pd, pool->max_message_size);
 684         if (IS_ERR(mr)) {
 685                 err = PTR_ERR(mr);
 686
 687                 printk(KERN_WARNING "RDS/IW: ib_alloc_fast_reg_mr failed (err=%d)\n", err);
 688                 return err;
 689         }
 690
 691         /* FIXME - this is overkill, but mapping->m_sg.dma_len/mapping->m_sg.dma_npages
 692          * is not filled in.
 693          */
 694         page_list = ib_alloc_fast_reg_page_list(rds_iwdev->dev, pool->max_message_size);
 695         if (IS_ERR(page_list)) {
 696                 err = PTR_ERR(page_list);
 697
 698                 printk(KERN_WARNING "RDS/IW: ib_alloc_fast_reg_page_list failed (err=%d)\n", err);
 699                 ib_dereg_mr(mr);
 700                 return err;
 701         }
 702
 703         ibmr->page_list = page_list;
 704         ibmr->mr = mr;
 705         return 0;
 706 }
 707
 708 static int rds_iw_rdma_build_fastreg(struct rds_iw_mapping *mapping)
 709 {
 710         struct rds_iw_mr *ibmr = mapping->m_mr;
 711         struct ib_send_wr f_wr, *failed_wr;
 712         int ret;
 713
 714         /*
 715          * Perform a WR for the fast_reg_mr. Each individual page
 716          * in the sg list is added to the fast reg page list and placed
 717          * inside the fast_reg_mr WR.  The key used is a rolling 8bit
 718          * counter, which should guarantee uniqueness.
 719          */
 720         ib_update_fast_reg_key(ibmr->mr, ibmr->remap_count++);
 721         mapping->m_rkey = ibmr->mr->rkey;
 722
 723         memset(&f_wr, 0, sizeof(f_wr));
 724         f_wr.wr_id = RDS_IW_FAST_REG_WR_ID;
 725         f_wr.opcode = IB_WR_FAST_REG_MR;
 726         f_wr.wr.fast_reg.length = mapping->m_sg.bytes;
 727         f_wr.wr.fast_reg.rkey = mapping->m_rkey;
 728         f_wr.wr.fast_reg.page_list = ibmr->page_list;
 729         f_wr.wr.fast_reg.page_list_len = mapping->m_sg.dma_len;
 730         f_wr.wr.fast_reg.page_shift = ibmr->device->page_shift;
 731         f_wr.wr.fast_reg.access_flags = IB_ACCESS_LOCAL_WRITE |
 732                                 IB_ACCESS_REMOTE_READ |
 733                                 IB_ACCESS_REMOTE_WRITE;
 734         f_wr.wr.fast_reg.iova_start = 0;
 735         f_wr.send_flags = IB_SEND_SIGNALED;
 736
 737         failed_wr = &f_wr;
 738         ret = ib_post_send(ibmr->cm_id->qp, &f_wr, &failed_wr);
 739         BUG_ON(failed_wr != &f_wr);
 740         if (ret && printk_ratelimit())
 741                 printk(KERN_WARNING "RDS/IW: %s:%d ib_post_send returned %d\n",
 742                         __func__, __LINE__, ret);
 743         return ret;
 744 }
 745
 746 static int rds_iw_rdma_fastreg_inv(struct rds_iw_mr *ibmr)
 747 {
 748         struct ib_send_wr s_wr, *failed_wr;
 749         int ret = 0;
 750
 751         if (!ibmr->cm_id->qp || !ibmr->mr)
 752                 goto out;
 753
 754         memset(&s_wr, 0, sizeof(s_wr));
 755         s_wr.wr_id = RDS_IW_LOCAL_INV_WR_ID;
 756         s_wr.opcode = IB_WR_LOCAL_INV;
 757         s_wr.ex.invalidate_rkey = ibmr->mr->rkey;
 758         s_wr.send_flags = IB_SEND_SIGNALED;
 759
 760         failed_wr = &s_wr;
 761         ret = ib_post_send(ibmr->cm_id->qp, &s_wr, &failed_wr);
 762         if (ret && printk_ratelimit()) {
 763                 printk(KERN_WARNING "RDS/IW: %s:%d ib_post_send returned %d\n",
 764                         __func__, __LINE__, ret);
 765                 goto out;
 766         }
 767 out:
 768         return ret;
 769 }
 770
 771 static int rds_iw_map_fastreg(struct rds_iw_mr_pool *pool,
 772                         struct rds_iw_mr *ibmr,
 773                         struct scatterlist *sg,
 774                         unsigned int sg_len)
 775 {
 776         struct rds_iw_device *rds_iwdev = pool->device;
 777         struct rds_iw_mapping *mapping = &ibmr->mapping;
 778         u64 *dma_pages;
 779         int i, ret = 0;
 780
 781         rds_iw_set_scatterlist(&mapping->m_sg, sg, sg_len);
 782
 783         dma_pages = rds_iw_map_scatterlist(rds_iwdev,
 784                                 &mapping->m_sg,
 785                                 rds_iwdev->page_shift);
 786         if (IS_ERR(dma_pages)) {
 787                 ret = PTR_ERR(dma_pages);
 788                 dma_pages = NULL;
 789                 goto out;
 790         }
 791
 792         if (mapping->m_sg.dma_len > pool->max_message_size) {
 793                 ret = -EMSGSIZE;
 794                 goto out;
 795         }
 796
 797         for (i = 0; i < mapping->m_sg.dma_npages; ++i)
 798                 ibmr->page_list->page_list[i] = dma_pages[i];
 799
 800         ret = rds_iw_rdma_build_fastreg(mapping);
 801         if (ret)
 802                 goto out;
 803
 804         rds_iw_stats_inc(s_iw_rdma_mr_used);
 805
 806 out:
 807         kfree(dma_pages);
 808
 809         return ret;
 810 }
 811
 812 /*
 813  * "Free" a fastreg MR.
 814  */
 815 static void rds_iw_free_fastreg(struct rds_iw_mr_pool *pool,
 816                 struct rds_iw_mr *ibmr)
 817 {
 818         unsigned long flags;
 819         int ret;
 820
 821         if (!ibmr->mapping.m_sg.dma_len)
 822                 return;
 823
 824         ret = rds_iw_rdma_fastreg_inv(ibmr);
 825         if (ret)
 826                 return;
 827
 828         /* Try to post the LOCAL_INV WR to the queue. */
 829         spin_lock_irqsave(&pool->list_lock, flags);
 830
 831         list_add_tail(&ibmr->mapping.m_list, &pool->dirty_list);
 832         atomic_add(ibmr->mapping.m_sg.len, &pool->free_pinned);
 833         atomic_inc(&pool->dirty_count);
 834
 835         spin_unlock_irqrestore(&pool->list_lock, flags);
 836 }
 837
 838 static unsigned int rds_iw_unmap_fastreg_list(struct rds_iw_mr_pool *pool,
 839                                 struct list_head *unmap_list,
 840                                 struct list_head *kill_list)
 841 {
 842         struct rds_iw_mapping *mapping, *next;
 843         unsigned int ncleaned = 0;
 844         LIST_HEAD(laundered);
 845
 846         /* Batched invalidation of fastreg MRs.
 847          * Why do we do it this way, even though we could pipeline unmap
 848          * and remap? The reason is the application semantics - when the
 849          * application requests an invalidation of MRs, it expects all
 850          * previously released R_Keys to become invalid.
 851          *
 852          * If we implement MR reuse naively, we risk memory corruption
 853          * (this has actually been observed). So the default behavior
 854          * requires that a MR goes through an explicit unmap operation before
 855          * we can reuse it again.
 856          *
 857          * We could probably improve on this a little, by allowing immediate
 858          * reuse of a MR on the same socket (eg you could add small
 859          * cache of unused MRs to strct rds_socket - GET_MR could grab one
 860          * of these without requiring an explicit invalidate).
 861          */
 862         while (!list_empty(unmap_list)) {
 863                 unsigned long flags;
 864
 865                 spin_lock_irqsave(&pool->list_lock, flags);
 866                 list_for_each_entry_safe(mapping, next, unmap_list, m_list) {
 867                         list_move(&mapping->m_list, &laundered);
 868                         ncleaned++;
 869                 }
 870                 spin_unlock_irqrestore(&pool->list_lock, flags);
 871         }
 872
 873         /* Move all laundered mappings back to the unmap list.
 874          * We do not kill any WRs right now - it doesn't seem the
 875          * fastreg API has a max_remap limit. */
 876         list_splice_init(&laundered, unmap_list);
 877
 878         return ncleaned;
 879 }
 880
 881 static void rds_iw_destroy_fastreg(struct rds_iw_mr_pool *pool,
 882                 struct rds_iw_mr *ibmr)
 883 {
 884         if (ibmr->page_list)
 885                 ib_free_fast_reg_page_list(ibmr->page_list);
 886         if (ibmr->mr)
 887                 ib_dereg_mr(ibmr->mr);
 888 }