root/net/rds/ib_frmr.c

DEFINITIONS

1. rds_transition_frwr_state
2. rds_ib_alloc_frmr
3. rds_ib_free_frmr
4. rds_ib_post_reg_frmr
5. rds_ib_map_frmr
6. rds_ib_post_inv
7. rds_ib_mr_cqe_handler
8. rds_ib_unreg_frmr
9. rds_ib_reg_frmr
10. rds_ib_free_frmr_list

   1 /*
   2  * Copyright (c) 2016 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 "ib_mr.h"
  34 
  35 static inline void
  36 rds_transition_frwr_state(struct rds_ib_mr *ibmr,
  37                           enum rds_ib_fr_state old_state,
  38                           enum rds_ib_fr_state new_state)
  39 {
  40         if (cmpxchg(&ibmr->u.frmr.fr_state,
  41                     old_state, new_state) == old_state &&
  42             old_state == FRMR_IS_INUSE) {
  43                 /* enforce order of ibmr->u.frmr.fr_state update
  44                  * before decrementing i_fastreg_inuse_count
  45                  */
  46                 smp_mb__before_atomic();
  47                 atomic_dec(&ibmr->ic->i_fastreg_inuse_count);
  48                 if (waitqueue_active(&rds_ib_ring_empty_wait))
  49                         wake_up(&rds_ib_ring_empty_wait);
  50         }
  51 }
  52 
  53 static struct rds_ib_mr *rds_ib_alloc_frmr(struct rds_ib_device *rds_ibdev,
  54                                            int npages)
  55 {
  56         struct rds_ib_mr_pool *pool;
  57         struct rds_ib_mr *ibmr = NULL;
  58         struct rds_ib_frmr *frmr;
  59         int err = 0;
  60 
  61         if (npages <= RDS_MR_8K_MSG_SIZE)
  62                 pool = rds_ibdev->mr_8k_pool;
  63         else
  64                 pool = rds_ibdev->mr_1m_pool;
  65 
  66         ibmr = rds_ib_try_reuse_ibmr(pool);
  67         if (ibmr)
  68                 return ibmr;
  69 
  70         ibmr = kzalloc_node(sizeof(*ibmr), GFP_KERNEL,
  71                             rdsibdev_to_node(rds_ibdev));
  72         if (!ibmr) {
  73                 err = -ENOMEM;
  74                 goto out_no_cigar;
  75         }
  76 
  77         frmr = &ibmr->u.frmr;
  78         frmr->mr = ib_alloc_mr(rds_ibdev->pd, IB_MR_TYPE_MEM_REG,
  79                          pool->fmr_attr.max_pages);
  80         if (IS_ERR(frmr->mr)) {
  81                 pr_warn("RDS/IB: %s failed to allocate MR", __func__);
  82                 err = PTR_ERR(frmr->mr);
  83                 goto out_no_cigar;
  84         }
  85 
  86         ibmr->pool = pool;
  87         if (pool->pool_type == RDS_IB_MR_8K_POOL)
  88                 rds_ib_stats_inc(s_ib_rdma_mr_8k_alloc);
  89         else
  90                 rds_ib_stats_inc(s_ib_rdma_mr_1m_alloc);
  91 
  92         if (atomic_read(&pool->item_count) > pool->max_items_soft)
  93                 pool->max_items_soft = pool->max_items;
  94 
  95         frmr->fr_state = FRMR_IS_FREE;
  96         init_waitqueue_head(&frmr->fr_inv_done);
  97         init_waitqueue_head(&frmr->fr_reg_done);
  98         return ibmr;
  99 
 100 out_no_cigar:
 101         kfree(ibmr);
 102         atomic_dec(&pool->item_count);
 103         return ERR_PTR(err);
 104 }
 105 
 106 static void rds_ib_free_frmr(struct rds_ib_mr *ibmr, bool drop)
 107 {
 108         struct rds_ib_mr_pool *pool = ibmr->pool;
 109 
 110         if (drop)
 111                 llist_add(&ibmr->llnode, &pool->drop_list);
 112         else
 113                 llist_add(&ibmr->llnode, &pool->free_list);
 114         atomic_add(ibmr->sg_len, &pool->free_pinned);
 115         atomic_inc(&pool->dirty_count);
 116 
 117         /* If we've pinned too many pages, request a flush */
 118         if (atomic_read(&pool->free_pinned) >= pool->max_free_pinned ||
 119             atomic_read(&pool->dirty_count) >= pool->max_items / 5)
 120                 queue_delayed_work(rds_ib_mr_wq, &pool->flush_worker, 10);
 121 }
 122 
 123 static int rds_ib_post_reg_frmr(struct rds_ib_mr *ibmr)
 124 {
 125         struct rds_ib_frmr *frmr = &ibmr->u.frmr;
 126         struct ib_reg_wr reg_wr;
 127         int ret, off = 0;
 128 
 129         while (atomic_dec_return(&ibmr->ic->i_fastreg_wrs) <= 0) {
 130                 atomic_inc(&ibmr->ic->i_fastreg_wrs);
 131                 cpu_relax();
 132         }
 133 
 134         ret = ib_map_mr_sg_zbva(frmr->mr, ibmr->sg, ibmr->sg_len,
 135                                 &off, PAGE_SIZE);
 136         if (unlikely(ret != ibmr->sg_len))
 137                 return ret < 0 ? ret : -EINVAL;
 138 
 139         if (cmpxchg(&frmr->fr_state,
 140                     FRMR_IS_FREE, FRMR_IS_INUSE) != FRMR_IS_FREE)
 141                 return -EBUSY;
 142 
 143         atomic_inc(&ibmr->ic->i_fastreg_inuse_count);
 144 
 145         /* Perform a WR for the fast_reg_mr. Each individual page
 146          * in the sg list is added to the fast reg page list and placed
 147          * inside the fast_reg_mr WR.  The key used is a rolling 8bit
 148          * counter, which should guarantee uniqueness.
 149          */
 150         ib_update_fast_reg_key(frmr->mr, ibmr->remap_count++);
 151         frmr->fr_reg = true;
 152 
 153         memset(&reg_wr, 0, sizeof(reg_wr));
 154         reg_wr.wr.wr_id = (unsigned long)(void *)ibmr;
 155         reg_wr.wr.opcode = IB_WR_REG_MR;
 156         reg_wr.wr.num_sge = 0;
 157         reg_wr.mr = frmr->mr;
 158         reg_wr.key = frmr->mr->rkey;
 159         reg_wr.access = IB_ACCESS_LOCAL_WRITE |
 160                         IB_ACCESS_REMOTE_READ |
 161                         IB_ACCESS_REMOTE_WRITE;
 162         reg_wr.wr.send_flags = IB_SEND_SIGNALED;
 163 
 164         ret = ib_post_send(ibmr->ic->i_cm_id->qp, &reg_wr.wr, NULL);
 165         if (unlikely(ret)) {
 166                 /* Failure here can be because of -ENOMEM as well */
 167                 rds_transition_frwr_state(ibmr, FRMR_IS_INUSE, FRMR_IS_STALE);
 168 
 169                 atomic_inc(&ibmr->ic->i_fastreg_wrs);
 170                 if (printk_ratelimit())
 171                         pr_warn("RDS/IB: %s returned error(%d)\n",
 172                                 __func__, ret);
 173                 goto out;
 174         }
 175 
 176         /* Wait for the registration to complete in order to prevent an invalid
 177          * access error resulting from a race between the memory region already
 178          * being accessed while registration is still pending.
 179          */
 180         wait_event(frmr->fr_reg_done, !frmr->fr_reg);
 181 
 182 out:
 183 
 184         return ret;
 185 }
 186 
 187 static int rds_ib_map_frmr(struct rds_ib_device *rds_ibdev,
 188                            struct rds_ib_mr_pool *pool,
 189                            struct rds_ib_mr *ibmr,
 190                            struct scatterlist *sg, unsigned int sg_len)
 191 {
 192         struct ib_device *dev = rds_ibdev->dev;
 193         struct rds_ib_frmr *frmr = &ibmr->u.frmr;
 194         int i;
 195         u32 len;
 196         int ret = 0;
 197 
 198         /* We want to teardown old ibmr values here and fill it up with
 199          * new sg values
 200          */
 201         rds_ib_teardown_mr(ibmr);
 202 
 203         ibmr->sg = sg;
 204         ibmr->sg_len = sg_len;
 205         ibmr->sg_dma_len = 0;
 206         frmr->sg_byte_len = 0;
 207         WARN_ON(ibmr->sg_dma_len);
 208         ibmr->sg_dma_len = ib_dma_map_sg(dev, ibmr->sg, ibmr->sg_len,
 209                                          DMA_BIDIRECTIONAL);
 210         if (unlikely(!ibmr->sg_dma_len)) {
 211                 pr_warn("RDS/IB: %s failed!\n", __func__);
 212                 return -EBUSY;
 213         }
 214 
 215         frmr->sg_byte_len = 0;
 216         frmr->dma_npages = 0;
 217         len = 0;
 218 
 219         ret = -EINVAL;
 220         for (i = 0; i < ibmr->sg_dma_len; ++i) {
 221                 unsigned int dma_len = sg_dma_len(&ibmr->sg[i]);
 222                 u64 dma_addr = sg_dma_address(&ibmr->sg[i]);
 223 
 224                 frmr->sg_byte_len += dma_len;
 225                 if (dma_addr & ~PAGE_MASK) {
 226                         if (i > 0)
 227                                 goto out_unmap;
 228                         else
 229                                 ++frmr->dma_npages;
 230                 }
 231 
 232                 if ((dma_addr + dma_len) & ~PAGE_MASK) {
 233                         if (i < ibmr->sg_dma_len - 1)
 234                                 goto out_unmap;
 235                         else
 236                                 ++frmr->dma_npages;
 237                 }
 238 
 239                 len += dma_len;
 240         }
 241         frmr->dma_npages += len >> PAGE_SHIFT;
 242 
 243         if (frmr->dma_npages > ibmr->pool->fmr_attr.max_pages) {
 244                 ret = -EMSGSIZE;
 245                 goto out_unmap;
 246         }
 247 
 248         ret = rds_ib_post_reg_frmr(ibmr);
 249         if (ret)
 250                 goto out_unmap;
 251 
 252         if (ibmr->pool->pool_type == RDS_IB_MR_8K_POOL)
 253                 rds_ib_stats_inc(s_ib_rdma_mr_8k_used);
 254         else
 255                 rds_ib_stats_inc(s_ib_rdma_mr_1m_used);
 256 
 257         return ret;
 258 
 259 out_unmap:
 260         ib_dma_unmap_sg(rds_ibdev->dev, ibmr->sg, ibmr->sg_len,
 261                         DMA_BIDIRECTIONAL);
 262         ibmr->sg_dma_len = 0;
 263         return ret;
 264 }
 265 
 266 static int rds_ib_post_inv(struct rds_ib_mr *ibmr)
 267 {
 268         struct ib_send_wr *s_wr;
 269         struct rds_ib_frmr *frmr = &ibmr->u.frmr;
 270         struct rdma_cm_id *i_cm_id = ibmr->ic->i_cm_id;
 271         int ret = -EINVAL;
 272 
 273         if (!i_cm_id || !i_cm_id->qp || !frmr->mr)
 274                 goto out;
 275 
 276         if (frmr->fr_state != FRMR_IS_INUSE)
 277                 goto out;
 278 
 279         while (atomic_dec_return(&ibmr->ic->i_fastreg_wrs) <= 0) {
 280                 atomic_inc(&ibmr->ic->i_fastreg_wrs);
 281                 cpu_relax();
 282         }
 283 
 284         frmr->fr_inv = true;
 285         s_wr = &frmr->fr_wr;
 286 
 287         memset(s_wr, 0, sizeof(*s_wr));
 288         s_wr->wr_id = (unsigned long)(void *)ibmr;
 289         s_wr->opcode = IB_WR_LOCAL_INV;
 290         s_wr->ex.invalidate_rkey = frmr->mr->rkey;
 291         s_wr->send_flags = IB_SEND_SIGNALED;
 292 
 293         ret = ib_post_send(i_cm_id->qp, s_wr, NULL);
 294         if (unlikely(ret)) {
 295                 rds_transition_frwr_state(ibmr, FRMR_IS_INUSE, FRMR_IS_STALE);
 296                 frmr->fr_inv = false;
 297                 /* enforce order of frmr->fr_inv update
 298                  * before incrementing i_fastreg_wrs
 299                  */
 300                 smp_mb__before_atomic();
 301                 atomic_inc(&ibmr->ic->i_fastreg_wrs);
 302                 pr_err("RDS/IB: %s returned error(%d)\n", __func__, ret);
 303                 goto out;
 304         }
 305 
 306         /* Wait for the FRMR_IS_FREE (or FRMR_IS_STALE) transition in order to
 307          * 1) avoid a silly bouncing between "clean_list" and "drop_list"
 308          *    triggered by function "rds_ib_reg_frmr" as it is releases frmr
 309          *    regions whose state is not "FRMR_IS_FREE" right away.
 310          * 2) prevents an invalid access error in a race
 311          *    from a pending "IB_WR_LOCAL_INV" operation
 312          *    with a teardown ("dma_unmap_sg", "put_page")
 313          *    and de-registration ("ib_dereg_mr") of the corresponding
 314          *    memory region.
 315          */
 316         wait_event(frmr->fr_inv_done, frmr->fr_state != FRMR_IS_INUSE);
 317 
 318 out:
 319         return ret;
 320 }
 321 
 322 void rds_ib_mr_cqe_handler(struct rds_ib_connection *ic, struct ib_wc *wc)
 323 {
 324         struct rds_ib_mr *ibmr = (void *)(unsigned long)wc->wr_id;
 325         struct rds_ib_frmr *frmr = &ibmr->u.frmr;
 326 
 327         if (wc->status != IB_WC_SUCCESS) {
 328                 rds_transition_frwr_state(ibmr, FRMR_IS_INUSE, FRMR_IS_STALE);
 329                 if (rds_conn_up(ic->conn))
 330                         rds_ib_conn_error(ic->conn,
 331                                           "frmr completion <%pI4,%pI4> status %u(%s), vendor_err 0x%x, disconnecting and reconnecting\n",
 332                                           &ic->conn->c_laddr,
 333                                           &ic->conn->c_faddr,
 334                                           wc->status,
 335                                           ib_wc_status_msg(wc->status),
 336                                           wc->vendor_err);
 337         }
 338 
 339         if (frmr->fr_inv) {
 340                 rds_transition_frwr_state(ibmr, FRMR_IS_INUSE, FRMR_IS_FREE);
 341                 frmr->fr_inv = false;
 342                 wake_up(&frmr->fr_inv_done);
 343         }
 344 
 345         if (frmr->fr_reg) {
 346                 frmr->fr_reg = false;
 347                 wake_up(&frmr->fr_reg_done);
 348         }
 349 
 350         /* enforce order of frmr->{fr_reg,fr_inv} update
 351          * before incrementing i_fastreg_wrs
 352          */
 353         smp_mb__before_atomic();
 354         atomic_inc(&ic->i_fastreg_wrs);
 355 }
 356 
 357 void rds_ib_unreg_frmr(struct list_head *list, unsigned int *nfreed,
 358                        unsigned long *unpinned, unsigned int goal)
 359 {
 360         struct rds_ib_mr *ibmr, *next;
 361         struct rds_ib_frmr *frmr;
 362         int ret = 0, ret2;
 363         unsigned int freed = *nfreed;
 364 
 365         /* String all ib_mr's onto one list and hand them to ib_unmap_fmr */
 366         list_for_each_entry(ibmr, list, unmap_list) {
 367                 if (ibmr->sg_dma_len) {
 368                         ret2 = rds_ib_post_inv(ibmr);
 369                         if (ret2 && !ret)
 370                                 ret = ret2;
 371                 }
 372         }
 373 
 374         if (ret)
 375                 pr_warn("RDS/IB: %s failed (err=%d)\n", __func__, ret);
 376 
 377         /* Now we can destroy the DMA mapping and unpin any pages */
 378         list_for_each_entry_safe(ibmr, next, list, unmap_list) {
 379                 *unpinned += ibmr->sg_len;
 380                 frmr = &ibmr->u.frmr;
 381                 __rds_ib_teardown_mr(ibmr);
 382                 if (freed < goal || frmr->fr_state == FRMR_IS_STALE) {
 383                         /* Don't de-allocate if the MR is not free yet */
 384                         if (frmr->fr_state == FRMR_IS_INUSE)
 385                                 continue;
 386 
 387                         if (ibmr->pool->pool_type == RDS_IB_MR_8K_POOL)
 388                                 rds_ib_stats_inc(s_ib_rdma_mr_8k_free);
 389                         else
 390                                 rds_ib_stats_inc(s_ib_rdma_mr_1m_free);
 391                         list_del(&ibmr->unmap_list);
 392                         if (frmr->mr)
 393                                 ib_dereg_mr(frmr->mr);
 394                         kfree(ibmr);
 395                         freed++;
 396                 }
 397         }
 398         *nfreed = freed;
 399 }
 400 
 401 struct rds_ib_mr *rds_ib_reg_frmr(struct rds_ib_device *rds_ibdev,
 402                                   struct rds_ib_connection *ic,
 403                                   struct scatterlist *sg,
 404                                   unsigned long nents, u32 *key)
 405 {
 406         struct rds_ib_mr *ibmr = NULL;
 407         struct rds_ib_frmr *frmr;
 408         int ret;
 409 
 410         if (!ic) {
 411                 /* TODO: Add FRWR support for RDS_GET_MR using proxy qp*/
 412                 return ERR_PTR(-EOPNOTSUPP);
 413         }
 414 
 415         do {
 416                 if (ibmr)
 417                         rds_ib_free_frmr(ibmr, true);
 418                 ibmr = rds_ib_alloc_frmr(rds_ibdev, nents);
 419                 if (IS_ERR(ibmr))
 420                         return ibmr;
 421                 frmr = &ibmr->u.frmr;
 422         } while (frmr->fr_state != FRMR_IS_FREE);
 423 
 424         ibmr->ic = ic;
 425         ibmr->device = rds_ibdev;
 426         ret = rds_ib_map_frmr(rds_ibdev, ibmr->pool, ibmr, sg, nents);
 427         if (ret == 0) {
 428                 *key = frmr->mr->rkey;
 429         } else {
 430                 rds_ib_free_frmr(ibmr, false);
 431                 ibmr = ERR_PTR(ret);
 432         }
 433 
 434         return ibmr;
 435 }
 436 
 437 void rds_ib_free_frmr_list(struct rds_ib_mr *ibmr)
 438 {
 439         struct rds_ib_mr_pool *pool = ibmr->pool;
 440         struct rds_ib_frmr *frmr = &ibmr->u.frmr;
 441 
 442         if (frmr->fr_state == FRMR_IS_STALE)
 443                 llist_add(&ibmr->llnode, &pool->drop_list);
 444         else
 445                 llist_add(&ibmr->llnode, &pool->free_list);
 446 }