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