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