drivers/infiniband/ulp/iser/iser_verbs.c

   1 /*
   2  * Copyright (c) 2004, 2005, 2006 Voltaire, Inc. All rights reserved.
   3  * Copyright (c) 2005, 2006 Cisco Systems.  All rights reserved.
   4  * Copyright (c) 2013-2014 Mellanox Technologies. All rights reserved.
   5  *
   6  * This software is available to you under a choice of one of two
   7  * licenses.  You may choose to be licensed under the terms of the GNU
   8  * General Public License (GPL) Version 2, available from the file
   9  * COPYING in the main directory of this source tree, or the
  10  * OpenIB.org BSD license below:
  11  *
  12  *     Redistribution and use in source and binary forms, with or
  13  *     without modification, are permitted provided that the following
  14  *     conditions are met:
  15  *
  16  *      - Redistributions of source code must retain the above
  17  *        copyright notice, this list of conditions and the following
  18  *        disclaimer.
  19  *
  20  *      - Redistributions in binary form must reproduce the above
  21  *        copyright notice, this list of conditions and the following
  22  *        disclaimer in the documentation and/or other materials
  23  *        provided with the distribution.
  24  *
  25  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  26  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  27  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  28  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  29  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  30  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  31  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  32  * SOFTWARE.
  33  */
  34 #include <linux/kernel.h>
  35 #include <linux/module.h>
  36 #include <linux/slab.h>
  37 #include <linux/delay.h>
  38
  39 #include "iscsi_iser.h"
  40
  41 #define ISCSI_ISER_MAX_CONN     8
  42 #define ISER_MAX_RX_LEN         (ISER_QP_MAX_RECV_DTOS * ISCSI_ISER_MAX_CONN)
  43 #define ISER_MAX_TX_LEN         (ISER_QP_MAX_REQ_DTOS  * ISCSI_ISER_MAX_CONN)
  44 #define ISER_MAX_CQ_LEN         (ISER_MAX_RX_LEN + ISER_MAX_TX_LEN + \
  45                                  ISCSI_ISER_MAX_CONN)
  46
  47 static int iser_cq_poll_limit = 512;
  48
  49 static void iser_cq_tasklet_fn(unsigned long data);
  50 static void iser_cq_callback(struct ib_cq *cq, void *cq_context);
  51
  52 static void iser_cq_event_callback(struct ib_event *cause, void *context)
  53 {
  54         iser_err("cq event %s (%d)\n",
  55                  ib_event_msg(cause->event), cause->event);
  56 }
  57
  58 static void iser_qp_event_callback(struct ib_event *cause, void *context)
  59 {
  60         iser_err("qp event %s (%d)\n",
  61                  ib_event_msg(cause->event), cause->event);
  62 }
  63
  64 static void iser_event_handler(struct ib_event_handler *handler,
  65                                 struct ib_event *event)
  66 {
  67         iser_err("async event %s (%d) on device %s port %d\n",
  68                  ib_event_msg(event->event), event->event,
  69                  event->device->name, event->element.port_num);
  70 }
  71
  72 /**
  73  * iser_create_device_ib_res - creates Protection Domain (PD), Completion
  74  * Queue (CQ), DMA Memory Region (DMA MR) with the device associated with
  75  * the adapator.
  76  *
  77  * returns 0 on success, -1 on failure
  78  */
  79 static int iser_create_device_ib_res(struct iser_device *device)
  80 {
  81         struct ib_device_attr *dev_attr = &device->dev_attr;
  82         int ret, i, max_cqe;
  83
  84         ret = ib_query_device(device->ib_device, dev_attr);
  85         if (ret) {
  86                 pr_warn("Query device failed for %s\n", device->ib_device->name);
  87                 return ret;
  88         }
  89
  90         /* Assign function handles  - based on FMR support */
  91         if (device->ib_device->alloc_fmr && device->ib_device->dealloc_fmr &&
  92             device->ib_device->map_phys_fmr && device->ib_device->unmap_fmr) {
  93                 iser_info("FMR supported, using FMR for registration\n");
  94                 device->iser_alloc_rdma_reg_res = iser_create_fmr_pool;
  95                 device->iser_free_rdma_reg_res = iser_free_fmr_pool;
  96                 device->iser_reg_rdma_mem = iser_reg_rdma_mem_fmr;
  97                 device->iser_unreg_rdma_mem = iser_unreg_mem_fmr;
  98         } else
  99         if (dev_attr->device_cap_flags & IB_DEVICE_MEM_MGT_EXTENSIONS) {
 100                 iser_info("FastReg supported, using FastReg for registration\n");
 101                 device->iser_alloc_rdma_reg_res = iser_create_fastreg_pool;
 102                 device->iser_free_rdma_reg_res = iser_free_fastreg_pool;
 103                 device->iser_reg_rdma_mem = iser_reg_rdma_mem_fastreg;
 104                 device->iser_unreg_rdma_mem = iser_unreg_mem_fastreg;
 105         } else {
 106                 iser_err("IB device does not support FMRs nor FastRegs, can't register memory\n");
 107                 return -1;
 108         }
 109
 110         device->comps_used = min_t(int, num_online_cpus(),
 111                                  device->ib_device->num_comp_vectors);
 112
 113         device->comps = kcalloc(device->comps_used, sizeof(*device->comps),
 114                                 GFP_KERNEL);
 115         if (!device->comps)
 116                 goto comps_err;
 117
 118         max_cqe = min(ISER_MAX_CQ_LEN, dev_attr->max_cqe);
 119
 120         iser_info("using %d CQs, device %s supports %d vectors max_cqe %d\n",
 121                   device->comps_used, device->ib_device->name,
 122                   device->ib_device->num_comp_vectors, max_cqe);
 123
 124         device->pd = ib_alloc_pd(device->ib_device);
 125         if (IS_ERR(device->pd))
 126                 goto pd_err;
 127
 128         for (i = 0; i < device->comps_used; i++) {
 129                 struct ib_cq_init_attr cq_attr = {};
 130                 struct iser_comp *comp = &device->comps[i];
 131
 132                 comp->device = device;
 133                 cq_attr.cqe = max_cqe;
 134                 cq_attr.comp_vector = i;
 135                 comp->cq = ib_create_cq(device->ib_device,
 136                                         iser_cq_callback,
 137                                         iser_cq_event_callback,
 138                                         (void *)comp,
 139                                         &cq_attr);
 140                 if (IS_ERR(comp->cq)) {
 141                         comp->cq = NULL;
 142                         goto cq_err;
 143                 }
 144
 145                 if (ib_req_notify_cq(comp->cq, IB_CQ_NEXT_COMP))
 146                         goto cq_err;
 147
 148                 tasklet_init(&comp->tasklet, iser_cq_tasklet_fn,
 149                              (unsigned long)comp);
 150         }
 151
 152         device->mr = ib_get_dma_mr(device->pd, IB_ACCESS_LOCAL_WRITE |
 153                                    IB_ACCESS_REMOTE_WRITE |
 154                                    IB_ACCESS_REMOTE_READ);
 155         if (IS_ERR(device->mr))
 156                 goto dma_mr_err;
 157
 158         INIT_IB_EVENT_HANDLER(&device->event_handler, device->ib_device,
 159                                 iser_event_handler);
 160         if (ib_register_event_handler(&device->event_handler))
 161                 goto handler_err;
 162
 163         return 0;
 164
 165 handler_err:
 166         ib_dereg_mr(device->mr);
 167 dma_mr_err:
 168         for (i = 0; i < device->comps_used; i++)
 169                 tasklet_kill(&device->comps[i].tasklet);
 170 cq_err:
 171         for (i = 0; i < device->comps_used; i++) {
 172                 struct iser_comp *comp = &device->comps[i];
 173
 174                 if (comp->cq)
 175                         ib_destroy_cq(comp->cq);
 176         }
 177         ib_dealloc_pd(device->pd);
 178 pd_err:
 179         kfree(device->comps);
 180 comps_err:
 181         iser_err("failed to allocate an IB resource\n");
 182         return -1;
 183 }
 184
 185 /**
 186  * iser_free_device_ib_res - destroy/dealloc/dereg the DMA MR,
 187  * CQ and PD created with the device associated with the adapator.
 188  */
 189 static void iser_free_device_ib_res(struct iser_device *device)
 190 {
 191         int i;
 192         BUG_ON(device->mr == NULL);
 193
 194         for (i = 0; i < device->comps_used; i++) {
 195                 struct iser_comp *comp = &device->comps[i];
 196
 197                 tasklet_kill(&comp->tasklet);
 198                 ib_destroy_cq(comp->cq);
 199                 comp->cq = NULL;
 200         }
 201
 202         (void)ib_unregister_event_handler(&device->event_handler);
 203         (void)ib_dereg_mr(device->mr);
 204         (void)ib_dealloc_pd(device->pd);
 205
 206         kfree(device->comps);
 207         device->comps = NULL;
 208
 209         device->mr = NULL;
 210         device->pd = NULL;
 211 }
 212
 213 /**
 214  * iser_create_fmr_pool - Creates FMR pool and page_vector
 215  *
 216  * returns 0 on success, or errno code on failure
 217  */
 218 int iser_create_fmr_pool(struct ib_conn *ib_conn, unsigned cmds_max)
 219 {
 220         struct iser_device *device = ib_conn->device;
 221         struct ib_fmr_pool_param params;
 222         int ret = -ENOMEM;
 223
 224         ib_conn->fmr.page_vec = kmalloc(sizeof(*ib_conn->fmr.page_vec) +
 225                                         (sizeof(u64)*(ISCSI_ISER_SG_TABLESIZE + 1)),
 226                                         GFP_KERNEL);
 227         if (!ib_conn->fmr.page_vec)
 228                 return ret;
 229
 230         ib_conn->fmr.page_vec->pages = (u64 *)(ib_conn->fmr.page_vec + 1);
 231
 232         params.page_shift        = SHIFT_4K;
 233         /* when the first/last SG element are not start/end *
 234          * page aligned, the map whould be of N+1 pages     */
 235         params.max_pages_per_fmr = ISCSI_ISER_SG_TABLESIZE + 1;
 236         /* make the pool size twice the max number of SCSI commands *
 237          * the ML is expected to queue, watermark for unmap at 50%  */
 238         params.pool_size         = cmds_max * 2;
 239         params.dirty_watermark   = cmds_max;
 240         params.cache             = 0;
 241         params.flush_function    = NULL;
 242         params.access            = (IB_ACCESS_LOCAL_WRITE  |
 243                                     IB_ACCESS_REMOTE_WRITE |
 244                                     IB_ACCESS_REMOTE_READ);
 245
 246         ib_conn->fmr.pool = ib_create_fmr_pool(device->pd, &params);
 247         if (!IS_ERR(ib_conn->fmr.pool))
 248                 return 0;
 249
 250         /* no FMR => no need for page_vec */
 251         kfree(ib_conn->fmr.page_vec);
 252         ib_conn->fmr.page_vec = NULL;
 253
 254         ret = PTR_ERR(ib_conn->fmr.pool);
 255         ib_conn->fmr.pool = NULL;
 256         if (ret != -ENOSYS) {
 257                 iser_err("FMR allocation failed, err %d\n", ret);
 258                 return ret;
 259         } else {
 260                 iser_warn("FMRs are not supported, using unaligned mode\n");
 261                 return 0;
 262         }
 263 }
 264
 265 /**
 266  * iser_free_fmr_pool - releases the FMR pool and page vec
 267  */
 268 void iser_free_fmr_pool(struct ib_conn *ib_conn)
 269 {
 270         iser_info("freeing conn %p fmr pool %p\n",
 271                   ib_conn, ib_conn->fmr.pool);
 272
 273         if (ib_conn->fmr.pool != NULL)
 274                 ib_destroy_fmr_pool(ib_conn->fmr.pool);
 275
 276         ib_conn->fmr.pool = NULL;
 277
 278         kfree(ib_conn->fmr.page_vec);
 279         ib_conn->fmr.page_vec = NULL;
 280 }
 281
 282 static int
 283 iser_alloc_pi_ctx(struct ib_device *ib_device, struct ib_pd *pd,
 284                   struct fast_reg_descriptor *desc)
 285 {
 286         struct iser_pi_context *pi_ctx = NULL;
 287         struct ib_mr_init_attr mr_init_attr = {.max_reg_descriptors = 2,
 288                                                .flags = IB_MR_SIGNATURE_EN};
 289         int ret = 0;
 290
 291         desc->pi_ctx = kzalloc(sizeof(*desc->pi_ctx), GFP_KERNEL);
 292         if (!desc->pi_ctx)
 293                 return -ENOMEM;
 294
 295         pi_ctx = desc->pi_ctx;
 296
 297         pi_ctx->prot_frpl = ib_alloc_fast_reg_page_list(ib_device,
 298                                             ISCSI_ISER_SG_TABLESIZE);
 299         if (IS_ERR(pi_ctx->prot_frpl)) {
 300                 ret = PTR_ERR(pi_ctx->prot_frpl);
 301                 goto prot_frpl_failure;
 302         }
 303
 304         pi_ctx->prot_mr = ib_alloc_fast_reg_mr(pd,
 305                                         ISCSI_ISER_SG_TABLESIZE + 1);
 306         if (IS_ERR(pi_ctx->prot_mr)) {
 307                 ret = PTR_ERR(pi_ctx->prot_mr);
 308                 goto prot_mr_failure;
 309         }
 310         desc->reg_indicators |= ISER_PROT_KEY_VALID;
 311
 312         pi_ctx->sig_mr = ib_create_mr(pd, &mr_init_attr);
 313         if (IS_ERR(pi_ctx->sig_mr)) {
 314                 ret = PTR_ERR(pi_ctx->sig_mr);
 315                 goto sig_mr_failure;
 316         }
 317         desc->reg_indicators |= ISER_SIG_KEY_VALID;
 318         desc->reg_indicators &= ~ISER_FASTREG_PROTECTED;
 319
 320         return 0;
 321
 322 sig_mr_failure:
 323         ib_dereg_mr(desc->pi_ctx->prot_mr);
 324 prot_mr_failure:
 325         ib_free_fast_reg_page_list(desc->pi_ctx->prot_frpl);
 326 prot_frpl_failure:
 327         kfree(desc->pi_ctx);
 328
 329         return ret;
 330 }
 331
 332 static void
 333 iser_free_pi_ctx(struct iser_pi_context *pi_ctx)
 334 {
 335         ib_free_fast_reg_page_list(pi_ctx->prot_frpl);
 336         ib_dereg_mr(pi_ctx->prot_mr);
 337         ib_destroy_mr(pi_ctx->sig_mr);
 338         kfree(pi_ctx);
 339 }
 340
 341 static int
 342 iser_create_fastreg_desc(struct ib_device *ib_device, struct ib_pd *pd,
 343                          bool pi_enable, struct fast_reg_descriptor *desc)
 344 {
 345         int ret;
 346
 347         desc->data_frpl = ib_alloc_fast_reg_page_list(ib_device,
 348                                                       ISCSI_ISER_SG_TABLESIZE + 1);
 349         if (IS_ERR(desc->data_frpl)) {
 350                 ret = PTR_ERR(desc->data_frpl);
 351                 iser_err("Failed to allocate ib_fast_reg_page_list err=%d\n",
 352                          ret);
 353                 return PTR_ERR(desc->data_frpl);
 354         }
 355
 356         desc->data_mr = ib_alloc_fast_reg_mr(pd, ISCSI_ISER_SG_TABLESIZE + 1);
 357         if (IS_ERR(desc->data_mr)) {
 358                 ret = PTR_ERR(desc->data_mr);
 359                 iser_err("Failed to allocate ib_fast_reg_mr err=%d\n", ret);
 360                 goto fast_reg_mr_failure;
 361         }
 362         desc->reg_indicators |= ISER_DATA_KEY_VALID;
 363
 364         if (pi_enable) {
 365                 ret = iser_alloc_pi_ctx(ib_device, pd, desc);
 366                 if (ret)
 367                         goto pi_ctx_alloc_failure;
 368         }
 369
 370         return 0;
 371 pi_ctx_alloc_failure:
 372         ib_dereg_mr(desc->data_mr);
 373 fast_reg_mr_failure:
 374         ib_free_fast_reg_page_list(desc->data_frpl);
 375
 376         return ret;
 377 }
 378
 379 /**
 380  * iser_create_fastreg_pool - Creates pool of fast_reg descriptors
 381  * for fast registration work requests.
 382  * returns 0 on success, or errno code on failure
 383  */
 384 int iser_create_fastreg_pool(struct ib_conn *ib_conn, unsigned cmds_max)
 385 {
 386         struct iser_device *device = ib_conn->device;
 387         struct fast_reg_descriptor *desc;
 388         int i, ret;
 389
 390         INIT_LIST_HEAD(&ib_conn->fastreg.pool);
 391         ib_conn->fastreg.pool_size = 0;
 392         for (i = 0; i < cmds_max; i++) {
 393                 desc = kzalloc(sizeof(*desc), GFP_KERNEL);
 394                 if (!desc) {
 395                         iser_err("Failed to allocate a new fast_reg descriptor\n");
 396                         ret = -ENOMEM;
 397                         goto err;
 398                 }
 399
 400                 ret = iser_create_fastreg_desc(device->ib_device, device->pd,
 401                                                ib_conn->pi_support, desc);
 402                 if (ret) {
 403                         iser_err("Failed to create fastreg descriptor err=%d\n",
 404                                  ret);
 405                         kfree(desc);
 406                         goto err;
 407                 }
 408
 409                 list_add_tail(&desc->list, &ib_conn->fastreg.pool);
 410                 ib_conn->fastreg.pool_size++;
 411         }
 412
 413         return 0;
 414
 415 err:
 416         iser_free_fastreg_pool(ib_conn);
 417         return ret;
 418 }
 419
 420 /**
 421  * iser_free_fastreg_pool - releases the pool of fast_reg descriptors
 422  */
 423 void iser_free_fastreg_pool(struct ib_conn *ib_conn)
 424 {
 425         struct fast_reg_descriptor *desc, *tmp;
 426         int i = 0;
 427
 428         if (list_empty(&ib_conn->fastreg.pool))
 429                 return;
 430
 431         iser_info("freeing conn %p fr pool\n", ib_conn);
 432
 433         list_for_each_entry_safe(desc, tmp, &ib_conn->fastreg.pool, list) {
 434                 list_del(&desc->list);
 435                 ib_free_fast_reg_page_list(desc->data_frpl);
 436                 ib_dereg_mr(desc->data_mr);
 437                 if (desc->pi_ctx)
 438                         iser_free_pi_ctx(desc->pi_ctx);
 439                 kfree(desc);
 440                 ++i;
 441         }
 442
 443         if (i < ib_conn->fastreg.pool_size)
 444                 iser_warn("pool still has %d regions registered\n",
 445                           ib_conn->fastreg.pool_size - i);
 446 }
 447
 448 /**
 449  * iser_create_ib_conn_res - Queue-Pair (QP)
 450  *
 451  * returns 0 on success, -1 on failure
 452  */
 453 static int iser_create_ib_conn_res(struct ib_conn *ib_conn)
 454 {
 455         struct iser_conn *iser_conn = container_of(ib_conn, struct iser_conn,
 456                                                    ib_conn);
 457         struct iser_device      *device;
 458         struct ib_device_attr *dev_attr;
 459         struct ib_qp_init_attr  init_attr;
 460         int                     ret = -ENOMEM;
 461         int index, min_index = 0;
 462
 463         BUG_ON(ib_conn->device == NULL);
 464
 465         device = ib_conn->device;
 466         dev_attr = &device->dev_attr;
 467
 468         memset(&init_attr, 0, sizeof init_attr);
 469
 470         mutex_lock(&ig.connlist_mutex);
 471         /* select the CQ with the minimal number of usages */
 472         for (index = 0; index < device->comps_used; index++) {
 473                 if (device->comps[index].active_qps <
 474                     device->comps[min_index].active_qps)
 475                         min_index = index;
 476         }
 477         ib_conn->comp = &device->comps[min_index];
 478         ib_conn->comp->active_qps++;
 479         mutex_unlock(&ig.connlist_mutex);
 480         iser_info("cq index %d used for ib_conn %p\n", min_index, ib_conn);
 481
 482         init_attr.event_handler = iser_qp_event_callback;
 483         init_attr.qp_context    = (void *)ib_conn;
 484         init_attr.send_cq       = ib_conn->comp->cq;
 485         init_attr.recv_cq       = ib_conn->comp->cq;
 486         init_attr.cap.max_recv_wr  = ISER_QP_MAX_RECV_DTOS;
 487         init_attr.cap.max_send_sge = 2;
 488         init_attr.cap.max_recv_sge = 1;
 489         init_attr.sq_sig_type   = IB_SIGNAL_REQ_WR;
 490         init_attr.qp_type       = IB_QPT_RC;
 491         if (ib_conn->pi_support) {
 492                 init_attr.cap.max_send_wr = ISER_QP_SIG_MAX_REQ_DTOS + 1;
 493                 init_attr.create_flags |= IB_QP_CREATE_SIGNATURE_EN;
 494                 iser_conn->max_cmds =
 495                         ISER_GET_MAX_XMIT_CMDS(ISER_QP_SIG_MAX_REQ_DTOS);
 496         } else {
 497                 if (dev_attr->max_qp_wr > ISER_QP_MAX_REQ_DTOS) {
 498                         init_attr.cap.max_send_wr  = ISER_QP_MAX_REQ_DTOS + 1;
 499                         iser_conn->max_cmds =
 500                                 ISER_GET_MAX_XMIT_CMDS(ISER_QP_MAX_REQ_DTOS);
 501                 } else {
 502                         init_attr.cap.max_send_wr = dev_attr->max_qp_wr;
 503                         iser_conn->max_cmds =
 504                                 ISER_GET_MAX_XMIT_CMDS(dev_attr->max_qp_wr);
 505                         iser_dbg("device %s supports max_send_wr %d\n",
 506                                  device->ib_device->name, dev_attr->max_qp_wr);
 507                 }
 508         }
 509
 510         ret = rdma_create_qp(ib_conn->cma_id, device->pd, &init_attr);
 511         if (ret)
 512                 goto out_err;
 513
 514         ib_conn->qp = ib_conn->cma_id->qp;
 515         iser_info("setting conn %p cma_id %p qp %p\n",
 516                   ib_conn, ib_conn->cma_id,
 517                   ib_conn->cma_id->qp);
 518         return ret;
 519
 520 out_err:
 521         mutex_lock(&ig.connlist_mutex);
 522         ib_conn->comp->active_qps--;
 523         mutex_unlock(&ig.connlist_mutex);
 524         iser_err("unable to alloc mem or create resource, err %d\n", ret);
 525
 526         return ret;
 527 }
 528
 529 /**
 530  * based on the resolved device node GUID see if there already allocated
 531  * device for this device. If there's no such, create one.
 532  */
 533 static
 534 struct iser_device *iser_device_find_by_ib_device(struct rdma_cm_id *cma_id)
 535 {
 536         struct iser_device *device;
 537
 538         mutex_lock(&ig.device_list_mutex);
 539
 540         list_for_each_entry(device, &ig.device_list, ig_list)
 541                 /* find if there's a match using the node GUID */
 542                 if (device->ib_device->node_guid == cma_id->device->node_guid)
 543                         goto inc_refcnt;
 544
 545         device = kzalloc(sizeof *device, GFP_KERNEL);
 546         if (device == NULL)
 547                 goto out;
 548
 549         /* assign this device to the device */
 550         device->ib_device = cma_id->device;
 551         /* init the device and link it into ig device list */
 552         if (iser_create_device_ib_res(device)) {
 553                 kfree(device);
 554                 device = NULL;
 555                 goto out;
 556         }
 557         list_add(&device->ig_list, &ig.device_list);
 558
 559 inc_refcnt:
 560         device->refcount++;
 561 out:
 562         mutex_unlock(&ig.device_list_mutex);
 563         return device;
 564 }
 565
 566 /* if there's no demand for this device, release it */
 567 static void iser_device_try_release(struct iser_device *device)
 568 {
 569         mutex_lock(&ig.device_list_mutex);
 570         device->refcount--;
 571         iser_info("device %p refcount %d\n", device, device->refcount);
 572         if (!device->refcount) {
 573                 iser_free_device_ib_res(device);
 574                 list_del(&device->ig_list);
 575                 kfree(device);
 576         }
 577         mutex_unlock(&ig.device_list_mutex);
 578 }
 579
 580 /**
 581  * Called with state mutex held
 582  **/
 583 static int iser_conn_state_comp_exch(struct iser_conn *iser_conn,
 584                                      enum iser_conn_state comp,
 585                                      enum iser_conn_state exch)
 586 {
 587         int ret;
 588
 589         ret = (iser_conn->state == comp);
 590         if (ret)
 591                 iser_conn->state = exch;
 592
 593         return ret;
 594 }
 595
 596 void iser_release_work(struct work_struct *work)
 597 {
 598         struct iser_conn *iser_conn;
 599
 600         iser_conn = container_of(work, struct iser_conn, release_work);
 601
 602         /* Wait for conn_stop to complete */
 603         wait_for_completion(&iser_conn->stop_completion);
 604         /* Wait for IB resouces cleanup to complete */
 605         wait_for_completion(&iser_conn->ib_completion);
 606
 607         mutex_lock(&iser_conn->state_mutex);
 608         iser_conn->state = ISER_CONN_DOWN;
 609         mutex_unlock(&iser_conn->state_mutex);
 610
 611         iser_conn_release(iser_conn);
 612 }
 613
 614 /**
 615  * iser_free_ib_conn_res - release IB related resources
 616  * @iser_conn: iser connection struct
 617  * @destroy: indicator if we need to try to release the
 618  *     iser device and memory regoins pool (only iscsi
 619  *     shutdown and DEVICE_REMOVAL will use this).
 620  *
 621  * This routine is called with the iser state mutex held
 622  * so the cm_id removal is out of here. It is Safe to
 623  * be invoked multiple times.
 624  */
 625 static void iser_free_ib_conn_res(struct iser_conn *iser_conn,
 626                                   bool destroy)
 627 {
 628         struct ib_conn *ib_conn = &iser_conn->ib_conn;
 629         struct iser_device *device = ib_conn->device;
 630
 631         iser_info("freeing conn %p cma_id %p qp %p\n",
 632                   iser_conn, ib_conn->cma_id, ib_conn->qp);
 633
 634         if (ib_conn->qp != NULL) {
 635                 ib_conn->comp->active_qps--;
 636                 rdma_destroy_qp(ib_conn->cma_id);
 637                 ib_conn->qp = NULL;
 638         }
 639
 640         if (destroy) {
 641                 if (iser_conn->rx_descs)
 642                         iser_free_rx_descriptors(iser_conn);
 643
 644                 if (device != NULL) {
 645                         iser_device_try_release(device);
 646                         ib_conn->device = NULL;
 647                 }
 648         }
 649 }
 650
 651 /**
 652  * Frees all conn objects and deallocs conn descriptor
 653  */
 654 void iser_conn_release(struct iser_conn *iser_conn)
 655 {
 656         struct ib_conn *ib_conn = &iser_conn->ib_conn;
 657
 658         mutex_lock(&ig.connlist_mutex);
 659         list_del(&iser_conn->conn_list);
 660         mutex_unlock(&ig.connlist_mutex);
 661
 662         mutex_lock(&iser_conn->state_mutex);
 663         /* In case we endup here without ep_disconnect being invoked. */
 664         if (iser_conn->state != ISER_CONN_DOWN) {
 665                 iser_warn("iser conn %p state %d, expected state down.\n",
 666                           iser_conn, iser_conn->state);
 667                 iscsi_destroy_endpoint(iser_conn->ep);
 668                 iser_conn->state = ISER_CONN_DOWN;
 669         }
 670         /*
 671          * In case we never got to bind stage, we still need to
 672          * release IB resources (which is safe to call more than once).
 673          */
 674         iser_free_ib_conn_res(iser_conn, true);
 675         mutex_unlock(&iser_conn->state_mutex);
 676
 677         if (ib_conn->cma_id != NULL) {
 678                 rdma_destroy_id(ib_conn->cma_id);
 679                 ib_conn->cma_id = NULL;
 680         }
 681
 682         kfree(iser_conn);
 683 }
 684
 685 /**
 686  * triggers start of the disconnect procedures and wait for them to be done
 687  * Called with state mutex held
 688  */
 689 int iser_conn_terminate(struct iser_conn *iser_conn)
 690 {
 691         struct ib_conn *ib_conn = &iser_conn->ib_conn;
 692         struct ib_send_wr *bad_wr;
 693         int err = 0;
 694
 695         /* terminate the iser conn only if the conn state is UP */
 696         if (!iser_conn_state_comp_exch(iser_conn, ISER_CONN_UP,
 697                                        ISER_CONN_TERMINATING))
 698                 return 0;
 699
 700         iser_info("iser_conn %p state %d\n", iser_conn, iser_conn->state);
 701
 702         /* suspend queuing of new iscsi commands */
 703         if (iser_conn->iscsi_conn)
 704                 iscsi_suspend_queue(iser_conn->iscsi_conn);
 705
 706         /*
 707          * In case we didn't already clean up the cma_id (peer initiated
 708          * a disconnection), we need to Cause the CMA to change the QP
 709          * state to ERROR.
 710          */
 711         if (ib_conn->cma_id) {
 712                 err = rdma_disconnect(ib_conn->cma_id);
 713                 if (err)
 714                         iser_err("Failed to disconnect, conn: 0x%p err %d\n",
 715                                  iser_conn, err);
 716
 717                 /* post an indication that all flush errors were consumed */
 718                 err = ib_post_send(ib_conn->qp, &ib_conn->beacon, &bad_wr);
 719                 if (err) {
 720                         iser_err("conn %p failed to post beacon", ib_conn);
 721                         return 1;
 722                 }
 723
 724                 wait_for_completion(&ib_conn->flush_comp);
 725         }
 726
 727         return 1;
 728 }
 729
 730 /**
 731  * Called with state mutex held
 732  **/
 733 static void iser_connect_error(struct rdma_cm_id *cma_id)
 734 {
 735         struct iser_conn *iser_conn;
 736
 737         iser_conn = (struct iser_conn *)cma_id->context;
 738         iser_conn->state = ISER_CONN_TERMINATING;
 739 }
 740
 741 /**
 742  * Called with state mutex held
 743  **/
 744 static void iser_addr_handler(struct rdma_cm_id *cma_id)
 745 {
 746         struct iser_device *device;
 747         struct iser_conn   *iser_conn;
 748         struct ib_conn   *ib_conn;
 749         int    ret;
 750
 751         iser_conn = (struct iser_conn *)cma_id->context;
 752         if (iser_conn->state != ISER_CONN_PENDING)
 753                 /* bailout */
 754                 return;
 755
 756         ib_conn = &iser_conn->ib_conn;
 757         device = iser_device_find_by_ib_device(cma_id);
 758         if (!device) {
 759                 iser_err("device lookup/creation failed\n");
 760                 iser_connect_error(cma_id);
 761                 return;
 762         }
 763
 764         ib_conn->device = device;
 765
 766         /* connection T10-PI support */
 767         if (iser_pi_enable) {
 768                 if (!(device->dev_attr.device_cap_flags &
 769                       IB_DEVICE_SIGNATURE_HANDOVER)) {
 770                         iser_warn("T10-PI requested but not supported on %s, "
 771                                   "continue without T10-PI\n",
 772                                   ib_conn->device->ib_device->name);
 773                         ib_conn->pi_support = false;
 774                 } else {
 775                         ib_conn->pi_support = true;
 776                 }
 777         }
 778
 779         ret = rdma_resolve_route(cma_id, 1000);
 780         if (ret) {
 781                 iser_err("resolve route failed: %d\n", ret);
 782                 iser_connect_error(cma_id);
 783                 return;
 784         }
 785 }
 786
 787 /**
 788  * Called with state mutex held
 789  **/
 790 static void iser_route_handler(struct rdma_cm_id *cma_id)
 791 {
 792         struct rdma_conn_param conn_param;
 793         int    ret;
 794         struct iser_cm_hdr req_hdr;
 795         struct iser_conn *iser_conn = (struct iser_conn *)cma_id->context;
 796         struct ib_conn *ib_conn = &iser_conn->ib_conn;
 797         struct iser_device *device = ib_conn->device;
 798
 799         if (iser_conn->state != ISER_CONN_PENDING)
 800                 /* bailout */
 801                 return;
 802
 803         ret = iser_create_ib_conn_res(ib_conn);
 804         if (ret)
 805                 goto failure;
 806
 807         memset(&conn_param, 0, sizeof conn_param);
 808         conn_param.responder_resources = device->dev_attr.max_qp_rd_atom;
 809         conn_param.initiator_depth     = 1;
 810         conn_param.retry_count         = 7;
 811         conn_param.rnr_retry_count     = 6;
 812
 813         memset(&req_hdr, 0, sizeof(req_hdr));
 814         req_hdr.flags = (ISER_ZBVA_NOT_SUPPORTED |
 815                         ISER_SEND_W_INV_NOT_SUPPORTED);
 816         conn_param.private_data         = (void *)&req_hdr;
 817         conn_param.private_data_len     = sizeof(struct iser_cm_hdr);
 818
 819         ret = rdma_connect(cma_id, &conn_param);
 820         if (ret) {
 821                 iser_err("failure connecting: %d\n", ret);
 822                 goto failure;
 823         }
 824
 825         return;
 826 failure:
 827         iser_connect_error(cma_id);
 828 }
 829
 830 static void iser_connected_handler(struct rdma_cm_id *cma_id)
 831 {
 832         struct iser_conn *iser_conn;
 833         struct ib_qp_attr attr;
 834         struct ib_qp_init_attr init_attr;
 835
 836         iser_conn = (struct iser_conn *)cma_id->context;
 837         if (iser_conn->state != ISER_CONN_PENDING)
 838                 /* bailout */
 839                 return;
 840
 841         (void)ib_query_qp(cma_id->qp, &attr, ~0, &init_attr);
 842         iser_info("remote qpn:%x my qpn:%x\n", attr.dest_qp_num, cma_id->qp->qp_num);
 843
 844         iser_conn->state = ISER_CONN_UP;
 845         complete(&iser_conn->up_completion);
 846 }
 847
 848 static void iser_disconnected_handler(struct rdma_cm_id *cma_id)
 849 {
 850         struct iser_conn *iser_conn = (struct iser_conn *)cma_id->context;
 851
 852         if (iser_conn_terminate(iser_conn)) {
 853                 if (iser_conn->iscsi_conn)
 854                         iscsi_conn_failure(iser_conn->iscsi_conn,
 855                                            ISCSI_ERR_CONN_FAILED);
 856                 else
 857                         iser_err("iscsi_iser connection isn't bound\n");
 858         }
 859 }
 860
 861 static void iser_cleanup_handler(struct rdma_cm_id *cma_id,
 862                                  bool destroy)
 863 {
 864         struct iser_conn *iser_conn = (struct iser_conn *)cma_id->context;
 865
 866         /*
 867          * We are not guaranteed that we visited disconnected_handler
 868          * by now, call it here to be safe that we handle CM drep
 869          * and flush errors.
 870          */
 871         iser_disconnected_handler(cma_id);
 872         iser_free_ib_conn_res(iser_conn, destroy);
 873         complete(&iser_conn->ib_completion);
 874 };
 875
 876 static int iser_cma_handler(struct rdma_cm_id *cma_id, struct rdma_cm_event *event)
 877 {
 878         struct iser_conn *iser_conn;
 879         int ret = 0;
 880
 881         iser_conn = (struct iser_conn *)cma_id->context;
 882         iser_info("%s (%d): status %d conn %p id %p\n",
 883                   rdma_event_msg(event->event), event->event,
 884                   event->status, cma_id->context, cma_id);
 885
 886         mutex_lock(&iser_conn->state_mutex);
 887         switch (event->event) {
 888         case RDMA_CM_EVENT_ADDR_RESOLVED:
 889                 iser_addr_handler(cma_id);
 890                 break;
 891         case RDMA_CM_EVENT_ROUTE_RESOLVED:
 892                 iser_route_handler(cma_id);
 893                 break;
 894         case RDMA_CM_EVENT_ESTABLISHED:
 895                 iser_connected_handler(cma_id);
 896                 break;
 897         case RDMA_CM_EVENT_ADDR_ERROR:
 898         case RDMA_CM_EVENT_ROUTE_ERROR:
 899         case RDMA_CM_EVENT_CONNECT_ERROR:
 900         case RDMA_CM_EVENT_UNREACHABLE:
 901         case RDMA_CM_EVENT_REJECTED:
 902                 iser_connect_error(cma_id);
 903                 break;
 904         case RDMA_CM_EVENT_DISCONNECTED:
 905         case RDMA_CM_EVENT_ADDR_CHANGE:
 906         case RDMA_CM_EVENT_TIMEWAIT_EXIT:
 907                 iser_cleanup_handler(cma_id, false);
 908                 break;
 909         case RDMA_CM_EVENT_DEVICE_REMOVAL:
 910                 /*
 911                  * we *must* destroy the device as we cannot rely
 912                  * on iscsid to be around to initiate error handling.
 913                  * also if we are not in state DOWN implicitly destroy
 914                  * the cma_id.
 915                  */
 916                 iser_cleanup_handler(cma_id, true);
 917                 if (iser_conn->state != ISER_CONN_DOWN) {
 918                         iser_conn->ib_conn.cma_id = NULL;
 919                         ret = 1;
 920                 }
 921                 break;
 922         default:
 923                 iser_err("Unexpected RDMA CM event: %s (%d)\n",
 924                          rdma_event_msg(event->event), event->event);
 925                 break;
 926         }
 927         mutex_unlock(&iser_conn->state_mutex);
 928
 929         return ret;
 930 }
 931
 932 void iser_conn_init(struct iser_conn *iser_conn)
 933 {
 934         iser_conn->state = ISER_CONN_INIT;
 935         iser_conn->ib_conn.post_recv_buf_count = 0;
 936         init_completion(&iser_conn->ib_conn.flush_comp);
 937         init_completion(&iser_conn->stop_completion);
 938         init_completion(&iser_conn->ib_completion);
 939         init_completion(&iser_conn->up_completion);
 940         INIT_LIST_HEAD(&iser_conn->conn_list);
 941         spin_lock_init(&iser_conn->ib_conn.lock);
 942         mutex_init(&iser_conn->state_mutex);
 943 }
 944
 945  /**
 946  * starts the process of connecting to the target
 947  * sleeps until the connection is established or rejected
 948  */
 949 int iser_connect(struct iser_conn   *iser_conn,
 950                  struct sockaddr    *src_addr,
 951                  struct sockaddr    *dst_addr,
 952                  int                 non_blocking)
 953 {
 954         struct ib_conn *ib_conn = &iser_conn->ib_conn;
 955         int err = 0;
 956
 957         mutex_lock(&iser_conn->state_mutex);
 958
 959         sprintf(iser_conn->name, "%pISp", dst_addr);
 960
 961         iser_info("connecting to: %s\n", iser_conn->name);
 962
 963         /* the device is known only --after-- address resolution */
 964         ib_conn->device = NULL;
 965
 966         iser_conn->state = ISER_CONN_PENDING;
 967
 968         ib_conn->beacon.wr_id = ISER_BEACON_WRID;
 969         ib_conn->beacon.opcode = IB_WR_SEND;
 970
 971         ib_conn->cma_id = rdma_create_id(iser_cma_handler,
 972                                          (void *)iser_conn,
 973                                          RDMA_PS_TCP, IB_QPT_RC);
 974         if (IS_ERR(ib_conn->cma_id)) {
 975                 err = PTR_ERR(ib_conn->cma_id);
 976                 iser_err("rdma_create_id failed: %d\n", err);
 977                 goto id_failure;
 978         }
 979
 980         err = rdma_resolve_addr(ib_conn->cma_id, src_addr, dst_addr, 1000);
 981         if (err) {
 982                 iser_err("rdma_resolve_addr failed: %d\n", err);
 983                 goto addr_failure;
 984         }
 985
 986         if (!non_blocking) {
 987                 wait_for_completion_interruptible(&iser_conn->up_completion);
 988
 989                 if (iser_conn->state != ISER_CONN_UP) {
 990                         err =  -EIO;
 991                         goto connect_failure;
 992                 }
 993         }
 994         mutex_unlock(&iser_conn->state_mutex);
 995
 996         mutex_lock(&ig.connlist_mutex);
 997         list_add(&iser_conn->conn_list, &ig.connlist);
 998         mutex_unlock(&ig.connlist_mutex);
 999         return 0;
1000
1001 id_failure:
1002         ib_conn->cma_id = NULL;
1003 addr_failure:
1004         iser_conn->state = ISER_CONN_DOWN;
1005 connect_failure:
1006         mutex_unlock(&iser_conn->state_mutex);
1007         iser_conn_release(iser_conn);
1008         return err;
1009 }
1010
1011 int iser_post_recvl(struct iser_conn *iser_conn)
1012 {
1013         struct ib_recv_wr rx_wr, *rx_wr_failed;
1014         struct ib_conn *ib_conn = &iser_conn->ib_conn;
1015         struct ib_sge     sge;
1016         int ib_ret;
1017
1018         sge.addr   = iser_conn->login_resp_dma;
1019         sge.length = ISER_RX_LOGIN_SIZE;
1020         sge.lkey   = ib_conn->device->mr->lkey;
1021
1022         rx_wr.wr_id   = (uintptr_t)iser_conn->login_resp_buf;
1023         rx_wr.sg_list = &sge;
1024         rx_wr.num_sge = 1;
1025         rx_wr.next    = NULL;
1026
1027         ib_conn->post_recv_buf_count++;
1028         ib_ret  = ib_post_recv(ib_conn->qp, &rx_wr, &rx_wr_failed);
1029         if (ib_ret) {
1030                 iser_err("ib_post_recv failed ret=%d\n", ib_ret);
1031                 ib_conn->post_recv_buf_count--;
1032         }
1033         return ib_ret;
1034 }
1035
1036 int iser_post_recvm(struct iser_conn *iser_conn, int count)
1037 {
1038         struct ib_recv_wr *rx_wr, *rx_wr_failed;
1039         int i, ib_ret;
1040         struct ib_conn *ib_conn = &iser_conn->ib_conn;
1041         unsigned int my_rx_head = iser_conn->rx_desc_head;
1042         struct iser_rx_desc *rx_desc;
1043
1044         for (rx_wr = ib_conn->rx_wr, i = 0; i < count; i++, rx_wr++) {
1045                 rx_desc         = &iser_conn->rx_descs[my_rx_head];
1046                 rx_wr->wr_id    = (uintptr_t)rx_desc;
1047                 rx_wr->sg_list  = &rx_desc->rx_sg;
1048                 rx_wr->num_sge  = 1;
1049                 rx_wr->next     = rx_wr + 1;
1050                 my_rx_head = (my_rx_head + 1) & iser_conn->qp_max_recv_dtos_mask;
1051         }
1052
1053         rx_wr--;
1054         rx_wr->next = NULL; /* mark end of work requests list */
1055
1056         ib_conn->post_recv_buf_count += count;
1057         ib_ret  = ib_post_recv(ib_conn->qp, ib_conn->rx_wr, &rx_wr_failed);
1058         if (ib_ret) {
1059                 iser_err("ib_post_recv failed ret=%d\n", ib_ret);
1060                 ib_conn->post_recv_buf_count -= count;
1061         } else
1062                 iser_conn->rx_desc_head = my_rx_head;
1063         return ib_ret;
1064 }
1065
1066
1067 /**
1068  * iser_start_send - Initiate a Send DTO operation
1069  *
1070  * returns 0 on success, -1 on failure
1071  */
1072 int iser_post_send(struct ib_conn *ib_conn, struct iser_tx_desc *tx_desc,
1073                    bool signal)
1074 {
1075         int               ib_ret;
1076         struct ib_send_wr send_wr, *send_wr_failed;
1077
1078         ib_dma_sync_single_for_device(ib_conn->device->ib_device,
1079                                       tx_desc->dma_addr, ISER_HEADERS_LEN,
1080                                       DMA_TO_DEVICE);
1081
1082         send_wr.next       = NULL;
1083         send_wr.wr_id      = (uintptr_t)tx_desc;
1084         send_wr.sg_list    = tx_desc->tx_sg;
1085         send_wr.num_sge    = tx_desc->num_sge;
1086         send_wr.opcode     = IB_WR_SEND;
1087         send_wr.send_flags = signal ? IB_SEND_SIGNALED : 0;
1088
1089         ib_ret = ib_post_send(ib_conn->qp, &send_wr, &send_wr_failed);
1090         if (ib_ret)
1091                 iser_err("ib_post_send failed, ret:%d\n", ib_ret);
1092
1093         return ib_ret;
1094 }
1095
1096 /**
1097  * is_iser_tx_desc - Indicate if the completion wr_id
1098  *     is a TX descriptor or not.
1099  * @iser_conn: iser connection
1100  * @wr_id: completion WR identifier
1101  *
1102  * Since we cannot rely on wc opcode in FLUSH errors
1103  * we must work around it by checking if the wr_id address
1104  * falls in the iser connection rx_descs buffer. If so
1105  * it is an RX descriptor, otherwize it is a TX.
1106  */
1107 static inline bool
1108 is_iser_tx_desc(struct iser_conn *iser_conn, void *wr_id)
1109 {
1110         void *start = iser_conn->rx_descs;
1111         int len = iser_conn->num_rx_descs * sizeof(*iser_conn->rx_descs);
1112
1113         if (wr_id >= start && wr_id < start + len)
1114                 return false;
1115
1116         return true;
1117 }
1118
1119 /**
1120  * iser_handle_comp_error() - Handle error completion
1121  * @ib_conn:   connection RDMA resources
1122  * @wc:        work completion
1123  *
1124  * Notes: We may handle a FLUSH error completion and in this case
1125  *        we only cleanup in case TX type was DATAOUT. For non-FLUSH
1126  *        error completion we should also notify iscsi layer that
1127  *        connection is failed (in case we passed bind stage).
1128  */
1129 static void
1130 iser_handle_comp_error(struct ib_conn *ib_conn,
1131                        struct ib_wc *wc)
1132 {
1133         void *wr_id = (void *)(uintptr_t)wc->wr_id;
1134         struct iser_conn *iser_conn = container_of(ib_conn, struct iser_conn,
1135                                                    ib_conn);
1136
1137         if (wc->status != IB_WC_WR_FLUSH_ERR)
1138                 if (iser_conn->iscsi_conn)
1139                         iscsi_conn_failure(iser_conn->iscsi_conn,
1140                                            ISCSI_ERR_CONN_FAILED);
1141
1142         if (wc->wr_id == ISER_FASTREG_LI_WRID)
1143                 return;
1144
1145         if (is_iser_tx_desc(iser_conn, wr_id)) {
1146                 struct iser_tx_desc *desc = wr_id;
1147
1148                 if (desc->type == ISCSI_TX_DATAOUT)
1149                         kmem_cache_free(ig.desc_cache, desc);
1150         } else {
1151                 ib_conn->post_recv_buf_count--;
1152         }
1153 }
1154
1155 /**
1156  * iser_handle_wc - handle a single work completion
1157  * @wc: work completion
1158  *
1159  * Soft-IRQ context, work completion can be either
1160  * SEND or RECV, and can turn out successful or
1161  * with error (or flush error).
1162  */
1163 static void iser_handle_wc(struct ib_wc *wc)
1164 {
1165         struct ib_conn *ib_conn;
1166         struct iser_tx_desc *tx_desc;
1167         struct iser_rx_desc *rx_desc;
1168
1169         ib_conn = wc->qp->qp_context;
1170         if (likely(wc->status == IB_WC_SUCCESS)) {
1171                 if (wc->opcode == IB_WC_RECV) {
1172                         rx_desc = (struct iser_rx_desc *)(uintptr_t)wc->wr_id;
1173                         iser_rcv_completion(rx_desc, wc->byte_len,
1174                                             ib_conn);
1175                 } else
1176                 if (wc->opcode == IB_WC_SEND) {
1177                         tx_desc = (struct iser_tx_desc *)(uintptr_t)wc->wr_id;
1178                         iser_snd_completion(tx_desc, ib_conn);
1179                 } else {
1180                         iser_err("Unknown wc opcode %d\n", wc->opcode);
1181                 }
1182         } else {
1183                 if (wc->status != IB_WC_WR_FLUSH_ERR)
1184                         iser_err("%s (%d): wr id %llx vend_err %x\n",
1185                                  ib_wc_status_msg(wc->status), wc->status,
1186                                  wc->wr_id, wc->vendor_err);
1187                 else
1188                         iser_dbg("%s (%d): wr id %llx\n",
1189                                  ib_wc_status_msg(wc->status), wc->status,
1190                                  wc->wr_id);
1191
1192                 if (wc->wr_id == ISER_BEACON_WRID)
1193                         /* all flush errors were consumed */
1194                         complete(&ib_conn->flush_comp);
1195                 else
1196                         iser_handle_comp_error(ib_conn, wc);
1197         }
1198 }
1199
1200 /**
1201  * iser_cq_tasklet_fn - iSER completion polling loop
1202  * @data: iSER completion context
1203  *
1204  * Soft-IRQ context, polling connection CQ until
1205  * either CQ was empty or we exausted polling budget
1206  */
1207 static void iser_cq_tasklet_fn(unsigned long data)
1208 {
1209         struct iser_comp *comp = (struct iser_comp *)data;
1210         struct ib_cq *cq = comp->cq;
1211         struct ib_wc *const wcs = comp->wcs;
1212         int i, n, completed = 0;
1213
1214         while ((n = ib_poll_cq(cq, ARRAY_SIZE(comp->wcs), wcs)) > 0) {
1215                 for (i = 0; i < n; i++)
1216                         iser_handle_wc(&wcs[i]);
1217
1218                 completed += n;
1219                 if (completed >= iser_cq_poll_limit)
1220                         break;
1221         }
1222
1223         /*
1224          * It is assumed here that arming CQ only once its empty
1225          * would not cause interrupts to be missed.
1226          */
1227         ib_req_notify_cq(cq, IB_CQ_NEXT_COMP);
1228
1229         iser_dbg("got %d completions\n", completed);
1230 }
1231
1232 static void iser_cq_callback(struct ib_cq *cq, void *cq_context)
1233 {
1234         struct iser_comp *comp = cq_context;
1235
1236         tasklet_schedule(&comp->tasklet);
1237 }
1238
1239 u8 iser_check_task_pi_status(struct iscsi_iser_task *iser_task,
1240                              enum iser_data_dir cmd_dir, sector_t *sector)
1241 {
1242         struct iser_mem_reg *reg = &iser_task->rdma_reg[cmd_dir];
1243         struct fast_reg_descriptor *desc = reg->mem_h;
1244         unsigned long sector_size = iser_task->sc->device->sector_size;
1245         struct ib_mr_status mr_status;
1246         int ret;
1247
1248         if (desc && desc->reg_indicators & ISER_FASTREG_PROTECTED) {
1249                 desc->reg_indicators &= ~ISER_FASTREG_PROTECTED;
1250                 ret = ib_check_mr_status(desc->pi_ctx->sig_mr,
1251                                          IB_MR_CHECK_SIG_STATUS, &mr_status);
1252                 if (ret) {
1253                         pr_err("ib_check_mr_status failed, ret %d\n", ret);
1254                         goto err;
1255                 }
1256
1257                 if (mr_status.fail_status & IB_MR_CHECK_SIG_STATUS) {
1258                         sector_t sector_off = mr_status.sig_err.sig_err_offset;
1259
1260                         do_div(sector_off, sector_size + 8);
1261                         *sector = scsi_get_lba(iser_task->sc) + sector_off;
1262
1263                         pr_err("PI error found type %d at sector %llx "
1264                                "expected %x vs actual %x\n",
1265                                mr_status.sig_err.err_type,
1266                                (unsigned long long)*sector,
1267                                mr_status.sig_err.expected,
1268                                mr_status.sig_err.actual);
1269
1270                         switch (mr_status.sig_err.err_type) {
1271                         case IB_SIG_BAD_GUARD:
1272                                 return 0x1;
1273                         case IB_SIG_BAD_REFTAG:
1274                                 return 0x3;
1275                         case IB_SIG_BAD_APPTAG:
1276                                 return 0x2;
1277                         }
1278                 }
1279         }
1280
1281         return 0;
1282 err:
1283         /* Not alot we can do here, return ambiguous guard error */
1284         return 0x1;
1285 }