drivers/infiniband/ulp/iser/iser_memory.c

   1 /*
   2  * Copyright (c) 2004, 2005, 2006 Voltaire, Inc. All rights reserved.
   3  * Copyright (c) 2013-2014 Mellanox Technologies. All rights reserved.
   4  *
   5  * This software is available to you under a choice of one of two
   6  * licenses.  You may choose to be licensed under the terms of the GNU
   7  * General Public License (GPL) Version 2, available from the file
   8  * COPYING in the main directory of this source tree, or the
   9  * OpenIB.org BSD license below:
  10  *
  11  *     Redistribution and use in source and binary forms, with or
  12  *     without modification, are permitted provided that the following
  13  *     conditions are met:
  14  *
  15  *      - Redistributions of source code must retain the above
  16  *        copyright notice, this list of conditions and the following
  17  *        disclaimer.
  18  *
  19  *      - Redistributions in binary form must reproduce the above
  20  *        copyright notice, this list of conditions and the following
  21  *        disclaimer in the documentation and/or other materials
  22  *        provided with the distribution.
  23  *
  24  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  25  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  26  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  27  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  28  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  29  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  30  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  31  * SOFTWARE.
  32  */
  33 #include <linux/module.h>
  34 #include <linux/kernel.h>
  35 #include <linux/slab.h>
  36 #include <linux/mm.h>
  37 #include <linux/highmem.h>
  38 #include <linux/scatterlist.h>
  39
  40 #include "iscsi_iser.h"
  41 static
  42 int iser_fast_reg_fmr(struct iscsi_iser_task *iser_task,
  43                       struct iser_data_buf *mem,
  44                       struct iser_reg_resources *rsc,
  45                       struct iser_mem_reg *mem_reg);
  46 static
  47 int iser_fast_reg_mr(struct iscsi_iser_task *iser_task,
  48                      struct iser_data_buf *mem,
  49                      struct iser_reg_resources *rsc,
  50                      struct iser_mem_reg *mem_reg);
  51
  52 static struct iser_reg_ops fastreg_ops = {
  53         .alloc_reg_res  = iser_alloc_fastreg_pool,
  54         .free_reg_res   = iser_free_fastreg_pool,
  55         .reg_mem        = iser_fast_reg_mr,
  56         .unreg_mem      = iser_unreg_mem_fastreg,
  57         .reg_desc_get   = iser_reg_desc_get_fr,
  58         .reg_desc_put   = iser_reg_desc_put_fr,
  59 };
  60
  61 static struct iser_reg_ops fmr_ops = {
  62         .alloc_reg_res  = iser_alloc_fmr_pool,
  63         .free_reg_res   = iser_free_fmr_pool,
  64         .reg_mem        = iser_fast_reg_fmr,
  65         .unreg_mem      = iser_unreg_mem_fmr,
  66         .reg_desc_get   = iser_reg_desc_get_fmr,
  67         .reg_desc_put   = iser_reg_desc_put_fmr,
  68 };
  69
  70 int iser_assign_reg_ops(struct iser_device *device)
  71 {
  72         struct ib_device_attr *dev_attr = &device->dev_attr;
  73
  74         /* Assign function handles  - based on FMR support */
  75         if (device->ib_device->alloc_fmr && device->ib_device->dealloc_fmr &&
  76             device->ib_device->map_phys_fmr && device->ib_device->unmap_fmr) {
  77                 iser_info("FMR supported, using FMR for registration\n");
  78                 device->reg_ops = &fmr_ops;
  79         } else
  80         if (dev_attr->device_cap_flags & IB_DEVICE_MEM_MGT_EXTENSIONS) {
  81                 iser_info("FastReg supported, using FastReg for registration\n");
  82                 device->reg_ops = &fastreg_ops;
  83         } else {
  84                 iser_err("IB device does not support FMRs nor FastRegs, can't register memory\n");
  85                 return -1;
  86         }
  87
  88         return 0;
  89 }
  90
  91 struct iser_fr_desc *
  92 iser_reg_desc_get_fr(struct ib_conn *ib_conn)
  93 {
  94         struct iser_fr_pool *fr_pool = &ib_conn->fr_pool;
  95         struct iser_fr_desc *desc;
  96         unsigned long flags;
  97
  98         spin_lock_irqsave(&fr_pool->lock, flags);
  99         desc = list_first_entry(&fr_pool->list,
 100                                 struct iser_fr_desc, list);
 101         list_del(&desc->list);
 102         spin_unlock_irqrestore(&fr_pool->lock, flags);
 103
 104         return desc;
 105 }
 106
 107 void
 108 iser_reg_desc_put_fr(struct ib_conn *ib_conn,
 109                      struct iser_fr_desc *desc)
 110 {
 111         struct iser_fr_pool *fr_pool = &ib_conn->fr_pool;
 112         unsigned long flags;
 113
 114         spin_lock_irqsave(&fr_pool->lock, flags);
 115         list_add(&desc->list, &fr_pool->list);
 116         spin_unlock_irqrestore(&fr_pool->lock, flags);
 117 }
 118
 119 struct iser_fr_desc *
 120 iser_reg_desc_get_fmr(struct ib_conn *ib_conn)
 121 {
 122         struct iser_fr_pool *fr_pool = &ib_conn->fr_pool;
 123
 124         return list_first_entry(&fr_pool->list,
 125                                 struct iser_fr_desc, list);
 126 }
 127
 128 void
 129 iser_reg_desc_put_fmr(struct ib_conn *ib_conn,
 130                       struct iser_fr_desc *desc)
 131 {
 132 }
 133
 134 #define IS_4K_ALIGNED(addr)     ((((unsigned long)addr) & ~MASK_4K) == 0)
 135
 136 /**
 137  * iser_sg_to_page_vec - Translates scatterlist entries to physical addresses
 138  * and returns the length of resulting physical address array (may be less than
 139  * the original due to possible compaction).
 140  *
 141  * we build a "page vec" under the assumption that the SG meets the RDMA
 142  * alignment requirements. Other then the first and last SG elements, all
 143  * the "internal" elements can be compacted into a list whose elements are
 144  * dma addresses of physical pages. The code supports also the weird case
 145  * where --few fragments of the same page-- are present in the SG as
 146  * consecutive elements. Also, it handles one entry SG.
 147  */
 148
 149 static int iser_sg_to_page_vec(struct iser_data_buf *data,
 150                                struct ib_device *ibdev, u64 *pages,
 151                                int *offset, int *data_size)
 152 {
 153         struct scatterlist *sg, *sgl = data->sg;
 154         u64 start_addr, end_addr, page, chunk_start = 0;
 155         unsigned long total_sz = 0;
 156         unsigned int dma_len;
 157         int i, new_chunk, cur_page, last_ent = data->dma_nents - 1;
 158
 159         /* compute the offset of first element */
 160         *offset = (u64) sgl[0].offset & ~MASK_4K;
 161
 162         new_chunk = 1;
 163         cur_page  = 0;
 164         for_each_sg(sgl, sg, data->dma_nents, i) {
 165                 start_addr = ib_sg_dma_address(ibdev, sg);
 166                 if (new_chunk)
 167                         chunk_start = start_addr;
 168                 dma_len = ib_sg_dma_len(ibdev, sg);
 169                 end_addr = start_addr + dma_len;
 170                 total_sz += dma_len;
 171
 172                 /* collect page fragments until aligned or end of SG list */
 173                 if (!IS_4K_ALIGNED(end_addr) && i < last_ent) {
 174                         new_chunk = 0;
 175                         continue;
 176                 }
 177                 new_chunk = 1;
 178
 179                 /* address of the first page in the contiguous chunk;
 180                    masking relevant for the very first SG entry,
 181                    which might be unaligned */
 182                 page = chunk_start & MASK_4K;
 183                 do {
 184                         pages[cur_page++] = page;
 185                         page += SIZE_4K;
 186                 } while (page < end_addr);
 187         }
 188
 189         *data_size = total_sz;
 190         iser_dbg("page_vec->data_size:%d cur_page %d\n",
 191                  *data_size, cur_page);
 192         return cur_page;
 193 }
 194
 195 static void iser_data_buf_dump(struct iser_data_buf *data,
 196                                struct ib_device *ibdev)
 197 {
 198         struct scatterlist *sg;
 199         int i;
 200
 201         for_each_sg(data->sg, sg, data->dma_nents, i)
 202                 iser_dbg("sg[%d] dma_addr:0x%lX page:0x%p "
 203                          "off:0x%x sz:0x%x dma_len:0x%x\n",
 204                          i, (unsigned long)ib_sg_dma_address(ibdev, sg),
 205                          sg_page(sg), sg->offset,
 206                          sg->length, ib_sg_dma_len(ibdev, sg));
 207 }
 208
 209 static void iser_dump_page_vec(struct iser_page_vec *page_vec)
 210 {
 211         int i;
 212
 213         iser_err("page vec length %d data size %d\n",
 214                  page_vec->length, page_vec->data_size);
 215         for (i = 0; i < page_vec->length; i++)
 216                 iser_err("%d %lx\n",i,(unsigned long)page_vec->pages[i]);
 217 }
 218
 219 int iser_dma_map_task_data(struct iscsi_iser_task *iser_task,
 220                             struct iser_data_buf *data,
 221                             enum iser_data_dir iser_dir,
 222                             enum dma_data_direction dma_dir)
 223 {
 224         struct ib_device *dev;
 225
 226         iser_task->dir[iser_dir] = 1;
 227         dev = iser_task->iser_conn->ib_conn.device->ib_device;
 228
 229         data->dma_nents = ib_dma_map_sg(dev, data->sg, data->size, dma_dir);
 230         if (data->dma_nents == 0) {
 231                 iser_err("dma_map_sg failed!!!\n");
 232                 return -EINVAL;
 233         }
 234         return 0;
 235 }
 236
 237 void iser_dma_unmap_task_data(struct iscsi_iser_task *iser_task,
 238                               struct iser_data_buf *data,
 239                               enum dma_data_direction dir)
 240 {
 241         struct ib_device *dev;
 242
 243         dev = iser_task->iser_conn->ib_conn.device->ib_device;
 244         ib_dma_unmap_sg(dev, data->sg, data->size, dir);
 245 }
 246
 247 static int
 248 iser_reg_dma(struct iser_device *device, struct iser_data_buf *mem,
 249              struct iser_mem_reg *reg)
 250 {
 251         struct scatterlist *sg = mem->sg;
 252
 253         reg->sge.lkey = device->pd->local_dma_lkey;
 254         reg->rkey = device->mr->rkey;
 255         reg->sge.addr = ib_sg_dma_address(device->ib_device, &sg[0]);
 256         reg->sge.length = ib_sg_dma_len(device->ib_device, &sg[0]);
 257
 258         iser_dbg("Single DMA entry: lkey=0x%x, rkey=0x%x, addr=0x%llx,"
 259                  " length=0x%x\n", reg->sge.lkey, reg->rkey,
 260                  reg->sge.addr, reg->sge.length);
 261
 262         return 0;
 263 }
 264
 265 /**
 266  * iser_reg_page_vec - Register physical memory
 267  *
 268  * returns: 0 on success, errno code on failure
 269  */
 270 static
 271 int iser_fast_reg_fmr(struct iscsi_iser_task *iser_task,
 272                       struct iser_data_buf *mem,
 273                       struct iser_reg_resources *rsc,
 274                       struct iser_mem_reg *reg)
 275 {
 276         struct ib_conn *ib_conn = &iser_task->iser_conn->ib_conn;
 277         struct iser_device *device = ib_conn->device;
 278         struct iser_page_vec *page_vec = rsc->page_vec;
 279         struct ib_fmr_pool *fmr_pool = rsc->fmr_pool;
 280         struct ib_pool_fmr *fmr;
 281         int ret, plen;
 282
 283         plen = iser_sg_to_page_vec(mem, device->ib_device,
 284                                    page_vec->pages,
 285                                    &page_vec->offset,
 286                                    &page_vec->data_size);
 287         page_vec->length = plen;
 288         if (plen * SIZE_4K < page_vec->data_size) {
 289                 iser_err("page vec too short to hold this SG\n");
 290                 iser_data_buf_dump(mem, device->ib_device);
 291                 iser_dump_page_vec(page_vec);
 292                 return -EINVAL;
 293         }
 294
 295         fmr  = ib_fmr_pool_map_phys(fmr_pool,
 296                                     page_vec->pages,
 297                                     page_vec->length,
 298                                     page_vec->pages[0]);
 299         if (IS_ERR(fmr)) {
 300                 ret = PTR_ERR(fmr);
 301                 iser_err("ib_fmr_pool_map_phys failed: %d\n", ret);
 302                 return ret;
 303         }
 304
 305         reg->sge.lkey = fmr->fmr->lkey;
 306         reg->rkey = fmr->fmr->rkey;
 307         reg->sge.addr = page_vec->pages[0] + page_vec->offset;
 308         reg->sge.length = page_vec->data_size;
 309         reg->mem_h = fmr;
 310
 311         iser_dbg("fmr reg: lkey=0x%x, rkey=0x%x, addr=0x%llx,"
 312                  " length=0x%x\n", reg->sge.lkey, reg->rkey,
 313                  reg->sge.addr, reg->sge.length);
 314
 315         return 0;
 316 }
 317
 318 /**
 319  * Unregister (previosuly registered using FMR) memory.
 320  * If memory is non-FMR does nothing.
 321  */
 322 void iser_unreg_mem_fmr(struct iscsi_iser_task *iser_task,
 323                         enum iser_data_dir cmd_dir)
 324 {
 325         struct iser_mem_reg *reg = &iser_task->rdma_reg[cmd_dir];
 326         int ret;
 327
 328         if (!reg->mem_h)
 329                 return;
 330
 331         iser_dbg("PHYSICAL Mem.Unregister mem_h %p\n", reg->mem_h);
 332
 333         ret = ib_fmr_pool_unmap((struct ib_pool_fmr *)reg->mem_h);
 334         if (ret)
 335                 iser_err("ib_fmr_pool_unmap failed %d\n", ret);
 336
 337         reg->mem_h = NULL;
 338 }
 339
 340 void iser_unreg_mem_fastreg(struct iscsi_iser_task *iser_task,
 341                             enum iser_data_dir cmd_dir)
 342 {
 343         struct iser_device *device = iser_task->iser_conn->ib_conn.device;
 344         struct iser_mem_reg *reg = &iser_task->rdma_reg[cmd_dir];
 345
 346         if (!reg->mem_h)
 347                 return;
 348
 349         device->reg_ops->reg_desc_put(&iser_task->iser_conn->ib_conn,
 350                                      reg->mem_h);
 351         reg->mem_h = NULL;
 352 }
 353
 354 static void
 355 iser_set_dif_domain(struct scsi_cmnd *sc, struct ib_sig_attrs *sig_attrs,
 356                     struct ib_sig_domain *domain)
 357 {
 358         domain->sig_type = IB_SIG_TYPE_T10_DIF;
 359         domain->sig.dif.pi_interval = scsi_prot_interval(sc);
 360         domain->sig.dif.ref_tag = scsi_prot_ref_tag(sc);
 361         /*
 362          * At the moment we hard code those, but in the future
 363          * we will take them from sc.
 364          */
 365         domain->sig.dif.apptag_check_mask = 0xffff;
 366         domain->sig.dif.app_escape = true;
 367         domain->sig.dif.ref_escape = true;
 368         if (sc->prot_flags & SCSI_PROT_REF_INCREMENT)
 369                 domain->sig.dif.ref_remap = true;
 370 };
 371
 372 static int
 373 iser_set_sig_attrs(struct scsi_cmnd *sc, struct ib_sig_attrs *sig_attrs)
 374 {
 375         switch (scsi_get_prot_op(sc)) {
 376         case SCSI_PROT_WRITE_INSERT:
 377         case SCSI_PROT_READ_STRIP:
 378                 sig_attrs->mem.sig_type = IB_SIG_TYPE_NONE;
 379                 iser_set_dif_domain(sc, sig_attrs, &sig_attrs->wire);
 380                 sig_attrs->wire.sig.dif.bg_type = IB_T10DIF_CRC;
 381                 break;
 382         case SCSI_PROT_READ_INSERT:
 383         case SCSI_PROT_WRITE_STRIP:
 384                 sig_attrs->wire.sig_type = IB_SIG_TYPE_NONE;
 385                 iser_set_dif_domain(sc, sig_attrs, &sig_attrs->mem);
 386                 sig_attrs->mem.sig.dif.bg_type = sc->prot_flags & SCSI_PROT_IP_CHECKSUM ?
 387                                                 IB_T10DIF_CSUM : IB_T10DIF_CRC;
 388                 break;
 389         case SCSI_PROT_READ_PASS:
 390         case SCSI_PROT_WRITE_PASS:
 391                 iser_set_dif_domain(sc, sig_attrs, &sig_attrs->wire);
 392                 sig_attrs->wire.sig.dif.bg_type = IB_T10DIF_CRC;
 393                 iser_set_dif_domain(sc, sig_attrs, &sig_attrs->mem);
 394                 sig_attrs->mem.sig.dif.bg_type = sc->prot_flags & SCSI_PROT_IP_CHECKSUM ?
 395                                                 IB_T10DIF_CSUM : IB_T10DIF_CRC;
 396                 break;
 397         default:
 398                 iser_err("Unsupported PI operation %d\n",
 399                          scsi_get_prot_op(sc));
 400                 return -EINVAL;
 401         }
 402
 403         return 0;
 404 }
 405
 406 static inline void
 407 iser_set_prot_checks(struct scsi_cmnd *sc, u8 *mask)
 408 {
 409         *mask = 0;
 410         if (sc->prot_flags & SCSI_PROT_REF_CHECK)
 411                 *mask |= ISER_CHECK_REFTAG;
 412         if (sc->prot_flags & SCSI_PROT_GUARD_CHECK)
 413                 *mask |= ISER_CHECK_GUARD;
 414 }
 415
 416 static void
 417 iser_inv_rkey(struct ib_send_wr *inv_wr, struct ib_mr *mr)
 418 {
 419         u32 rkey;
 420
 421         inv_wr->opcode = IB_WR_LOCAL_INV;
 422         inv_wr->wr_id = ISER_FASTREG_LI_WRID;
 423         inv_wr->ex.invalidate_rkey = mr->rkey;
 424         inv_wr->send_flags = 0;
 425         inv_wr->num_sge = 0;
 426
 427         rkey = ib_inc_rkey(mr->rkey);
 428         ib_update_fast_reg_key(mr, rkey);
 429 }
 430
 431 static int
 432 iser_reg_sig_mr(struct iscsi_iser_task *iser_task,
 433                 struct iser_pi_context *pi_ctx,
 434                 struct iser_mem_reg *data_reg,
 435                 struct iser_mem_reg *prot_reg,
 436                 struct iser_mem_reg *sig_reg)
 437 {
 438         struct iser_tx_desc *tx_desc = &iser_task->desc;
 439         struct ib_sig_attrs *sig_attrs = &tx_desc->sig_attrs;
 440         struct ib_sig_handover_wr *wr;
 441         int ret;
 442
 443         memset(sig_attrs, 0, sizeof(*sig_attrs));
 444         ret = iser_set_sig_attrs(iser_task->sc, sig_attrs);
 445         if (ret)
 446                 goto err;
 447
 448         iser_set_prot_checks(iser_task->sc, &sig_attrs->check_mask);
 449
 450         if (!pi_ctx->sig_mr_valid)
 451                 iser_inv_rkey(iser_tx_next_wr(tx_desc), pi_ctx->sig_mr);
 452
 453         wr = sig_handover_wr(iser_tx_next_wr(tx_desc));
 454         wr->wr.opcode = IB_WR_REG_SIG_MR;
 455         wr->wr.wr_id = ISER_FASTREG_LI_WRID;
 456         wr->wr.sg_list = &data_reg->sge;
 457         wr->wr.num_sge = 1;
 458         wr->wr.send_flags = 0;
 459         wr->sig_attrs = sig_attrs;
 460         wr->sig_mr = pi_ctx->sig_mr;
 461         if (scsi_prot_sg_count(iser_task->sc))
 462                 wr->prot = &prot_reg->sge;
 463         else
 464                 wr->prot = NULL;
 465         wr->access_flags = IB_ACCESS_LOCAL_WRITE |
 466                            IB_ACCESS_REMOTE_READ |
 467                            IB_ACCESS_REMOTE_WRITE;
 468         pi_ctx->sig_mr_valid = 0;
 469
 470         sig_reg->sge.lkey = pi_ctx->sig_mr->lkey;
 471         sig_reg->rkey = pi_ctx->sig_mr->rkey;
 472         sig_reg->sge.addr = 0;
 473         sig_reg->sge.length = scsi_transfer_length(iser_task->sc);
 474
 475         iser_dbg("lkey=0x%x rkey=0x%x addr=0x%llx length=%u\n",
 476                  sig_reg->sge.lkey, sig_reg->rkey, sig_reg->sge.addr,
 477                  sig_reg->sge.length);
 478 err:
 479         return ret;
 480 }
 481
 482 static int iser_fast_reg_mr(struct iscsi_iser_task *iser_task,
 483                             struct iser_data_buf *mem,
 484                             struct iser_reg_resources *rsc,
 485                             struct iser_mem_reg *reg)
 486 {
 487         struct iser_tx_desc *tx_desc = &iser_task->desc;
 488         struct ib_mr *mr = rsc->mr;
 489         struct ib_reg_wr *wr;
 490         int n;
 491
 492         if (!rsc->mr_valid)
 493                 iser_inv_rkey(iser_tx_next_wr(tx_desc), mr);
 494
 495         n = ib_map_mr_sg(mr, mem->sg, mem->size, SIZE_4K);
 496         if (unlikely(n != mem->size)) {
 497                 iser_err("failed to map sg (%d/%d)\n",
 498                          n, mem->size);
 499                 return n < 0 ? n : -EINVAL;
 500         }
 501
 502         wr = reg_wr(iser_tx_next_wr(tx_desc));
 503         wr->wr.opcode = IB_WR_REG_MR;
 504         wr->wr.wr_id = ISER_FASTREG_LI_WRID;
 505         wr->wr.send_flags = 0;
 506         wr->wr.num_sge = 0;
 507         wr->mr = mr;
 508         wr->key = mr->rkey;
 509         wr->access = IB_ACCESS_LOCAL_WRITE  |
 510                      IB_ACCESS_REMOTE_WRITE |
 511                      IB_ACCESS_REMOTE_READ;
 512
 513         rsc->mr_valid = 0;
 514
 515         reg->sge.lkey = mr->lkey;
 516         reg->rkey = mr->rkey;
 517         reg->sge.addr = mr->iova;
 518         reg->sge.length = mr->length;
 519
 520         iser_dbg("lkey=0x%x rkey=0x%x addr=0x%llx length=0x%x\n",
 521                  reg->sge.lkey, reg->rkey, reg->sge.addr, reg->sge.length);
 522
 523         return 0;
 524 }
 525
 526 static int
 527 iser_reg_prot_sg(struct iscsi_iser_task *task,
 528                  struct iser_data_buf *mem,
 529                  struct iser_fr_desc *desc,
 530                  bool use_dma_key,
 531                  struct iser_mem_reg *reg)
 532 {
 533         struct iser_device *device = task->iser_conn->ib_conn.device;
 534
 535         if (use_dma_key)
 536                 return iser_reg_dma(device, mem, reg);
 537
 538         return device->reg_ops->reg_mem(task, mem, &desc->pi_ctx->rsc, reg);
 539 }
 540
 541 static int
 542 iser_reg_data_sg(struct iscsi_iser_task *task,
 543                  struct iser_data_buf *mem,
 544                  struct iser_fr_desc *desc,
 545                  bool use_dma_key,
 546                  struct iser_mem_reg *reg)
 547 {
 548         struct iser_device *device = task->iser_conn->ib_conn.device;
 549
 550         if (use_dma_key)
 551                 return iser_reg_dma(device, mem, reg);
 552
 553         return device->reg_ops->reg_mem(task, mem, &desc->rsc, reg);
 554 }
 555
 556 int iser_reg_rdma_mem(struct iscsi_iser_task *task,
 557                       enum iser_data_dir dir)
 558 {
 559         struct ib_conn *ib_conn = &task->iser_conn->ib_conn;
 560         struct iser_device *device = ib_conn->device;
 561         struct iser_data_buf *mem = &task->data[dir];
 562         struct iser_mem_reg *reg = &task->rdma_reg[dir];
 563         struct iser_mem_reg *data_reg;
 564         struct iser_fr_desc *desc = NULL;
 565         bool use_dma_key;
 566         int err;
 567
 568         use_dma_key = (mem->dma_nents == 1 && !iser_always_reg &&
 569                        scsi_get_prot_op(task->sc) == SCSI_PROT_NORMAL);
 570
 571         if (!use_dma_key) {
 572                 desc = device->reg_ops->reg_desc_get(ib_conn);
 573                 reg->mem_h = desc;
 574         }
 575
 576         if (scsi_get_prot_op(task->sc) == SCSI_PROT_NORMAL)
 577                 data_reg = reg;
 578         else
 579                 data_reg = &task->desc.data_reg;
 580
 581         err = iser_reg_data_sg(task, mem, desc, use_dma_key, data_reg);
 582         if (unlikely(err))
 583                 goto err_reg;
 584
 585         if (scsi_get_prot_op(task->sc) != SCSI_PROT_NORMAL) {
 586                 struct iser_mem_reg *prot_reg = &task->desc.prot_reg;
 587
 588                 if (scsi_prot_sg_count(task->sc)) {
 589                         mem = &task->prot[dir];
 590                         err = iser_reg_prot_sg(task, mem, desc,
 591                                                use_dma_key, prot_reg);
 592                         if (unlikely(err))
 593                                 goto err_reg;
 594                 }
 595
 596                 err = iser_reg_sig_mr(task, desc->pi_ctx, data_reg,
 597                                       prot_reg, reg);
 598                 if (unlikely(err))
 599                         goto err_reg;
 600
 601                 desc->pi_ctx->sig_protected = 1;
 602         }
 603
 604         return 0;
 605
 606 err_reg:
 607         if (desc)
 608                 device->reg_ops->reg_desc_put(ib_conn, desc);
 609
 610         return err;
 611 }
 612
 613 void iser_unreg_rdma_mem(struct iscsi_iser_task *task,
 614                          enum iser_data_dir dir)
 615 {
 616         struct iser_device *device = task->iser_conn->ib_conn.device;
 617
 618         device->reg_ops->unreg_mem(task, dir);
 619 }