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