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         ret = iser_assign_reg_ops(device);
  91         if (ret)
  92                 return ret;
  93
  94         device->comps_used = min_t(int, num_online_cpus(),
  95                                  device->ib_device->num_comp_vectors);
  96
  97         device->comps = kcalloc(device->comps_used, sizeof(*device->comps),
  98                                 GFP_KERNEL);
  99         if (!device->comps)
 100                 goto comps_err;
 101
 102         max_cqe = min(ISER_MAX_CQ_LEN, dev_attr->max_cqe);
 103
 104         iser_info("using %d CQs, device %s supports %d vectors max_cqe %d\n",
 105                   device->comps_used, device->ib_device->name,
 106                   device->ib_device->num_comp_vectors, max_cqe);
 107
 108         device->pd = ib_alloc_pd(device->ib_device);
 109         if (IS_ERR(device->pd))
 110                 goto pd_err;
 111
 112         for (i = 0; i < device->comps_used; i++) {
 113                 struct ib_cq_init_attr cq_attr = {};
 114                 struct iser_comp *comp = &device->comps[i];
 115
 116                 comp->device = device;
 117                 cq_attr.cqe = max_cqe;
 118                 cq_attr.comp_vector = i;
 119                 comp->cq = ib_create_cq(device->ib_device,
 120                                         iser_cq_callback,
 121                                         iser_cq_event_callback,
 122                                         (void *)comp,
 123                                         &cq_attr);
 124                 if (IS_ERR(comp->cq)) {
 125                         comp->cq = NULL;
 126                         goto cq_err;
 127                 }
 128
 129                 if (ib_req_notify_cq(comp->cq, IB_CQ_NEXT_COMP))
 130                         goto cq_err;
 131
 132                 tasklet_init(&comp->tasklet, iser_cq_tasklet_fn,
 133                              (unsigned long)comp);
 134         }
 135
 136         if (!iser_always_reg) {
 137                 int access = IB_ACCESS_LOCAL_WRITE |
 138                              IB_ACCESS_REMOTE_WRITE |
 139                              IB_ACCESS_REMOTE_READ;
 140
 141                 device->mr = ib_get_dma_mr(device->pd, access);
 142                 if (IS_ERR(device->mr))
 143                         goto dma_mr_err;
 144         }
 145
 146         INIT_IB_EVENT_HANDLER(&device->event_handler, device->ib_device,
 147                                 iser_event_handler);
 148         if (ib_register_event_handler(&device->event_handler))
 149                 goto handler_err;
 150
 151         return 0;
 152
 153 handler_err:
 154         if (device->mr)
 155                 ib_dereg_mr(device->mr);
 156 dma_mr_err:
 157         for (i = 0; i < device->comps_used; i++)
 158                 tasklet_kill(&device->comps[i].tasklet);
 159 cq_err:
 160         for (i = 0; i < device->comps_used; i++) {
 161                 struct iser_comp *comp = &device->comps[i];
 162
 163                 if (comp->cq)
 164                         ib_destroy_cq(comp->cq);
 165         }
 166         ib_dealloc_pd(device->pd);
 167 pd_err:
 168         kfree(device->comps);
 169 comps_err:
 170         iser_err("failed to allocate an IB resource\n");
 171         return -1;
 172 }
 173
 174 /**
 175  * iser_free_device_ib_res - destroy/dealloc/dereg the DMA MR,
 176  * CQ and PD created with the device associated with the adapator.
 177  */
 178 static void iser_free_device_ib_res(struct iser_device *device)
 179 {
 180         int i;
 181
 182         for (i = 0; i < device->comps_used; i++) {
 183                 struct iser_comp *comp = &device->comps[i];
 184
 185                 tasklet_kill(&comp->tasklet);
 186                 ib_destroy_cq(comp->cq);
 187                 comp->cq = NULL;
 188         }
 189
 190         (void)ib_unregister_event_handler(&device->event_handler);
 191         if (device->mr)
 192                 (void)ib_dereg_mr(device->mr);
 193         ib_dealloc_pd(device->pd);
 194
 195         kfree(device->comps);
 196         device->comps = NULL;
 197
 198         device->mr = NULL;
 199         device->pd = NULL;
 200 }
 201
 202 /**
 203  * iser_alloc_fmr_pool - Creates FMR pool and page_vector
 204  *
 205  * returns 0 on success, or errno code on failure
 206  */
 207 int iser_alloc_fmr_pool(struct ib_conn *ib_conn,
 208                         unsigned cmds_max,
 209                         unsigned int size)
 210 {
 211         struct iser_device *device = ib_conn->device;
 212         struct iser_fr_pool *fr_pool = &ib_conn->fr_pool;
 213         struct iser_page_vec *page_vec;
 214         struct iser_fr_desc *desc;
 215         struct ib_fmr_pool *fmr_pool;
 216         struct ib_fmr_pool_param params;
 217         int ret;
 218
 219         INIT_LIST_HEAD(&fr_pool->list);
 220         spin_lock_init(&fr_pool->lock);
 221
 222         desc = kzalloc(sizeof(*desc), GFP_KERNEL);
 223         if (!desc)
 224                 return -ENOMEM;
 225
 226         page_vec = kmalloc(sizeof(*page_vec) + (sizeof(u64) * size),
 227                            GFP_KERNEL);
 228         if (!page_vec) {
 229                 ret = -ENOMEM;
 230                 goto err_frpl;
 231         }
 232
 233         page_vec->pages = (u64 *)(page_vec + 1);
 234
 235         params.page_shift        = SHIFT_4K;
 236         params.max_pages_per_fmr = size;
 237         /* make the pool size twice the max number of SCSI commands *
 238          * the ML is expected to queue, watermark for unmap at 50%  */
 239         params.pool_size         = cmds_max * 2;
 240         params.dirty_watermark   = cmds_max;
 241         params.cache             = 0;
 242         params.flush_function    = NULL;
 243         params.access            = (IB_ACCESS_LOCAL_WRITE  |
 244                                     IB_ACCESS_REMOTE_WRITE |
 245                                     IB_ACCESS_REMOTE_READ);
 246
 247         fmr_pool = ib_create_fmr_pool(device->pd, &params);
 248         if (IS_ERR(fmr_pool)) {
 249                 ret = PTR_ERR(fmr_pool);
 250                 iser_err("FMR allocation failed, err %d\n", ret);
 251                 goto err_fmr;
 252         }
 253
 254         desc->rsc.page_vec = page_vec;
 255         desc->rsc.fmr_pool = fmr_pool;
 256         list_add(&desc->list, &fr_pool->list);
 257
 258         return 0;
 259
 260 err_fmr:
 261         kfree(page_vec);
 262 err_frpl:
 263         kfree(desc);
 264
 265         return ret;
 266 }
 267
 268 /**
 269  * iser_free_fmr_pool - releases the FMR pool and page vec
 270  */
 271 void iser_free_fmr_pool(struct ib_conn *ib_conn)
 272 {
 273         struct iser_fr_pool *fr_pool = &ib_conn->fr_pool;
 274         struct iser_fr_desc *desc;
 275
 276         desc = list_first_entry(&fr_pool->list,
 277                                 struct iser_fr_desc, list);
 278         list_del(&desc->list);
 279
 280         iser_info("freeing conn %p fmr pool %p\n",
 281                   ib_conn, desc->rsc.fmr_pool);
 282
 283         ib_destroy_fmr_pool(desc->rsc.fmr_pool);
 284         kfree(desc->rsc.page_vec);
 285         kfree(desc);
 286 }
 287
 288 static int
 289 iser_alloc_reg_res(struct ib_device *ib_device,
 290                    struct ib_pd *pd,
 291                    struct iser_reg_resources *res,
 292                    unsigned int size)
 293 {
 294         int ret;
 295
 296         res->mr = ib_alloc_mr(pd, IB_MR_TYPE_MEM_REG, size);
 297         if (IS_ERR(res->mr)) {
 298                 ret = PTR_ERR(res->mr);
 299                 iser_err("Failed to allocate ib_fast_reg_mr err=%d\n", ret);
 300                 return ret;
 301         }
 302         res->mr_valid = 1;
 303
 304         return 0;
 305 }
 306
 307 static void
 308 iser_free_reg_res(struct iser_reg_resources *rsc)
 309 {
 310         ib_dereg_mr(rsc->mr);
 311 }
 312
 313 static int
 314 iser_alloc_pi_ctx(struct ib_device *ib_device,
 315                   struct ib_pd *pd,
 316                   struct iser_fr_desc *desc,
 317                   unsigned int size)
 318 {
 319         struct iser_pi_context *pi_ctx = NULL;
 320         int ret;
 321
 322         desc->pi_ctx = kzalloc(sizeof(*desc->pi_ctx), GFP_KERNEL);
 323         if (!desc->pi_ctx)
 324                 return -ENOMEM;
 325
 326         pi_ctx = desc->pi_ctx;
 327
 328         ret = iser_alloc_reg_res(ib_device, pd, &pi_ctx->rsc, size);
 329         if (ret) {
 330                 iser_err("failed to allocate reg_resources\n");
 331                 goto alloc_reg_res_err;
 332         }
 333
 334         pi_ctx->sig_mr = ib_alloc_mr(pd, IB_MR_TYPE_SIGNATURE, 2);
 335         if (IS_ERR(pi_ctx->sig_mr)) {
 336                 ret = PTR_ERR(pi_ctx->sig_mr);
 337                 goto sig_mr_failure;
 338         }
 339         pi_ctx->sig_mr_valid = 1;
 340         desc->pi_ctx->sig_protected = 0;
 341
 342         return 0;
 343
 344 sig_mr_failure:
 345         iser_free_reg_res(&pi_ctx->rsc);
 346 alloc_reg_res_err:
 347         kfree(desc->pi_ctx);
 348
 349         return ret;
 350 }
 351
 352 static void
 353 iser_free_pi_ctx(struct iser_pi_context *pi_ctx)
 354 {
 355         iser_free_reg_res(&pi_ctx->rsc);
 356         ib_dereg_mr(pi_ctx->sig_mr);
 357         kfree(pi_ctx);
 358 }
 359
 360 static struct iser_fr_desc *
 361 iser_create_fastreg_desc(struct ib_device *ib_device,
 362                          struct ib_pd *pd,
 363                          bool pi_enable,
 364                          unsigned int size)
 365 {
 366         struct iser_fr_desc *desc;
 367         int ret;
 368
 369         desc = kzalloc(sizeof(*desc), GFP_KERNEL);
 370         if (!desc)
 371                 return ERR_PTR(-ENOMEM);
 372
 373         ret = iser_alloc_reg_res(ib_device, pd, &desc->rsc, size);
 374         if (ret)
 375                 goto reg_res_alloc_failure;
 376
 377         if (pi_enable) {
 378                 ret = iser_alloc_pi_ctx(ib_device, pd, desc, size);
 379                 if (ret)
 380                         goto pi_ctx_alloc_failure;
 381         }
 382
 383         return desc;
 384
 385 pi_ctx_alloc_failure:
 386         iser_free_reg_res(&desc->rsc);
 387 reg_res_alloc_failure:
 388         kfree(desc);
 389
 390         return ERR_PTR(ret);
 391 }
 392
 393 /**
 394  * iser_alloc_fastreg_pool - Creates pool of fast_reg descriptors
 395  * for fast registration work requests.
 396  * returns 0 on success, or errno code on failure
 397  */
 398 int iser_alloc_fastreg_pool(struct ib_conn *ib_conn,
 399                             unsigned cmds_max,
 400                             unsigned int size)
 401 {
 402         struct iser_device *device = ib_conn->device;
 403         struct iser_fr_pool *fr_pool = &ib_conn->fr_pool;
 404         struct iser_fr_desc *desc;
 405         int i, ret;
 406
 407         INIT_LIST_HEAD(&fr_pool->list);
 408         INIT_LIST_HEAD(&fr_pool->all_list);
 409         spin_lock_init(&fr_pool->lock);
 410         fr_pool->size = 0;
 411         for (i = 0; i < cmds_max; i++) {
 412                 desc = iser_create_fastreg_desc(device->ib_device, device->pd,
 413                                                 ib_conn->pi_support, size);
 414                 if (IS_ERR(desc)) {
 415                         ret = PTR_ERR(desc);
 416                         goto err;
 417                 }
 418
 419                 list_add_tail(&desc->list, &fr_pool->list);
 420                 list_add_tail(&desc->all_list, &fr_pool->all_list);
 421                 fr_pool->size++;
 422         }
 423
 424         return 0;
 425
 426 err:
 427         iser_free_fastreg_pool(ib_conn);
 428         return ret;
 429 }
 430
 431 /**
 432  * iser_free_fastreg_pool - releases the pool of fast_reg descriptors
 433  */
 434 void iser_free_fastreg_pool(struct ib_conn *ib_conn)
 435 {
 436         struct iser_fr_pool *fr_pool = &ib_conn->fr_pool;
 437         struct iser_fr_desc *desc, *tmp;
 438         int i = 0;
 439
 440         if (list_empty(&fr_pool->all_list))
 441                 return;
 442
 443         iser_info("freeing conn %p fr pool\n", ib_conn);
 444
 445         list_for_each_entry_safe(desc, tmp, &fr_pool->all_list, all_list) {
 446                 list_del(&desc->all_list);
 447                 iser_free_reg_res(&desc->rsc);
 448                 if (desc->pi_ctx)
 449                         iser_free_pi_ctx(desc->pi_ctx);
 450                 kfree(desc);
 451                 ++i;
 452         }
 453
 454         if (i < fr_pool->size)
 455                 iser_warn("pool still has %d regions registered\n",
 456                           fr_pool->size - i);
 457 }
 458
 459 /**
 460  * iser_create_ib_conn_res - Queue-Pair (QP)
 461  *
 462  * returns 0 on success, -1 on failure
 463  */
 464 static int iser_create_ib_conn_res(struct ib_conn *ib_conn)
 465 {
 466         struct iser_conn *iser_conn = container_of(ib_conn, struct iser_conn,
 467                                                    ib_conn);
 468         struct iser_device      *device;
 469         struct ib_device_attr *dev_attr;
 470         struct ib_qp_init_attr  init_attr;
 471         int                     ret = -ENOMEM;
 472         int index, min_index = 0;
 473
 474         BUG_ON(ib_conn->device == NULL);
 475
 476         device = ib_conn->device;
 477         dev_attr = &device->dev_attr;
 478
 479         memset(&init_attr, 0, sizeof init_attr);
 480
 481         mutex_lock(&ig.connlist_mutex);
 482         /* select the CQ with the minimal number of usages */
 483         for (index = 0; index < device->comps_used; index++) {
 484                 if (device->comps[index].active_qps <
 485                     device->comps[min_index].active_qps)
 486                         min_index = index;
 487         }
 488         ib_conn->comp = &device->comps[min_index];
 489         ib_conn->comp->active_qps++;
 490         mutex_unlock(&ig.connlist_mutex);
 491         iser_info("cq index %d used for ib_conn %p\n", min_index, ib_conn);
 492
 493         init_attr.event_handler = iser_qp_event_callback;
 494         init_attr.qp_context    = (void *)ib_conn;
 495         init_attr.send_cq       = ib_conn->comp->cq;
 496         init_attr.recv_cq       = ib_conn->comp->cq;
 497         init_attr.cap.max_recv_wr  = ISER_QP_MAX_RECV_DTOS;
 498         init_attr.cap.max_send_sge = 2;
 499         init_attr.cap.max_recv_sge = 1;
 500         init_attr.sq_sig_type   = IB_SIGNAL_REQ_WR;
 501         init_attr.qp_type       = IB_QPT_RC;
 502         if (ib_conn->pi_support) {
 503                 init_attr.cap.max_send_wr = ISER_QP_SIG_MAX_REQ_DTOS + 1;
 504                 init_attr.create_flags |= IB_QP_CREATE_SIGNATURE_EN;
 505                 iser_conn->max_cmds =
 506                         ISER_GET_MAX_XMIT_CMDS(ISER_QP_SIG_MAX_REQ_DTOS);
 507         } else {
 508                 if (dev_attr->max_qp_wr > ISER_QP_MAX_REQ_DTOS) {
 509                         init_attr.cap.max_send_wr  = ISER_QP_MAX_REQ_DTOS + 1;
 510                         iser_conn->max_cmds =
 511                                 ISER_GET_MAX_XMIT_CMDS(ISER_QP_MAX_REQ_DTOS);
 512                 } else {
 513                         init_attr.cap.max_send_wr = dev_attr->max_qp_wr;
 514                         iser_conn->max_cmds =
 515                                 ISER_GET_MAX_XMIT_CMDS(dev_attr->max_qp_wr);
 516                         iser_dbg("device %s supports max_send_wr %d\n",
 517                                  device->ib_device->name, dev_attr->max_qp_wr);
 518                 }
 519         }
 520
 521         ret = rdma_create_qp(ib_conn->cma_id, device->pd, &init_attr);
 522         if (ret)
 523                 goto out_err;
 524
 525         ib_conn->qp = ib_conn->cma_id->qp;
 526         iser_info("setting conn %p cma_id %p qp %p\n",
 527                   ib_conn, ib_conn->cma_id,
 528                   ib_conn->cma_id->qp);
 529         return ret;
 530
 531 out_err:
 532         mutex_lock(&ig.connlist_mutex);
 533         ib_conn->comp->active_qps--;
 534         mutex_unlock(&ig.connlist_mutex);
 535         iser_err("unable to alloc mem or create resource, err %d\n", ret);
 536
 537         return ret;
 538 }
 539
 540 /**
 541  * based on the resolved device node GUID see if there already allocated
 542  * device for this device. If there's no such, create one.
 543  */
 544 static
 545 struct iser_device *iser_device_find_by_ib_device(struct rdma_cm_id *cma_id)
 546 {
 547         struct iser_device *device;
 548
 549         mutex_lock(&ig.device_list_mutex);
 550
 551         list_for_each_entry(device, &ig.device_list, ig_list)
 552                 /* find if there's a match using the node GUID */
 553                 if (device->ib_device->node_guid == cma_id->device->node_guid)
 554                         goto inc_refcnt;
 555
 556         device = kzalloc(sizeof *device, GFP_KERNEL);
 557         if (device == NULL)
 558                 goto out;
 559
 560         /* assign this device to the device */
 561         device->ib_device = cma_id->device;
 562         /* init the device and link it into ig device list */
 563         if (iser_create_device_ib_res(device)) {
 564                 kfree(device);
 565                 device = NULL;
 566                 goto out;
 567         }
 568         list_add(&device->ig_list, &ig.device_list);
 569
 570 inc_refcnt:
 571         device->refcount++;
 572 out:
 573         mutex_unlock(&ig.device_list_mutex);
 574         return device;
 575 }
 576
 577 /* if there's no demand for this device, release it */
 578 static void iser_device_try_release(struct iser_device *device)
 579 {
 580         mutex_lock(&ig.device_list_mutex);
 581         device->refcount--;
 582         iser_info("device %p refcount %d\n", device, device->refcount);
 583         if (!device->refcount) {
 584                 iser_free_device_ib_res(device);
 585                 list_del(&device->ig_list);
 586                 kfree(device);
 587         }
 588         mutex_unlock(&ig.device_list_mutex);
 589 }
 590
 591 /**
 592  * Called with state mutex held
 593  **/
 594 static int iser_conn_state_comp_exch(struct iser_conn *iser_conn,
 595                                      enum iser_conn_state comp,
 596                                      enum iser_conn_state exch)
 597 {
 598         int ret;
 599
 600         ret = (iser_conn->state == comp);
 601         if (ret)
 602                 iser_conn->state = exch;
 603
 604         return ret;
 605 }
 606
 607 void iser_release_work(struct work_struct *work)
 608 {
 609         struct iser_conn *iser_conn;
 610
 611         iser_conn = container_of(work, struct iser_conn, release_work);
 612
 613         /* Wait for conn_stop to complete */
 614         wait_for_completion(&iser_conn->stop_completion);
 615         /* Wait for IB resouces cleanup to complete */
 616         wait_for_completion(&iser_conn->ib_completion);
 617
 618         mutex_lock(&iser_conn->state_mutex);
 619         iser_conn->state = ISER_CONN_DOWN;
 620         mutex_unlock(&iser_conn->state_mutex);
 621
 622         iser_conn_release(iser_conn);
 623 }
 624
 625 /**
 626  * iser_free_ib_conn_res - release IB related resources
 627  * @iser_conn: iser connection struct
 628  * @destroy: indicator if we need to try to release the
 629  *     iser device and memory regoins pool (only iscsi
 630  *     shutdown and DEVICE_REMOVAL will use this).
 631  *
 632  * This routine is called with the iser state mutex held
 633  * so the cm_id removal is out of here. It is Safe to
 634  * be invoked multiple times.
 635  */
 636 static void iser_free_ib_conn_res(struct iser_conn *iser_conn,
 637                                   bool destroy)
 638 {
 639         struct ib_conn *ib_conn = &iser_conn->ib_conn;
 640         struct iser_device *device = ib_conn->device;
 641
 642         iser_info("freeing conn %p cma_id %p qp %p\n",
 643                   iser_conn, ib_conn->cma_id, ib_conn->qp);
 644
 645         if (ib_conn->qp != NULL) {
 646                 ib_conn->comp->active_qps--;
 647                 rdma_destroy_qp(ib_conn->cma_id);
 648                 ib_conn->qp = NULL;
 649         }
 650
 651         if (destroy) {
 652                 if (iser_conn->rx_descs)
 653                         iser_free_rx_descriptors(iser_conn);
 654
 655                 if (device != NULL) {
 656                         iser_device_try_release(device);
 657                         ib_conn->device = NULL;
 658                 }
 659         }
 660 }
 661
 662 /**
 663  * Frees all conn objects and deallocs conn descriptor
 664  */
 665 void iser_conn_release(struct iser_conn *iser_conn)
 666 {
 667         struct ib_conn *ib_conn = &iser_conn->ib_conn;
 668
 669         mutex_lock(&ig.connlist_mutex);
 670         list_del(&iser_conn->conn_list);
 671         mutex_unlock(&ig.connlist_mutex);
 672
 673         mutex_lock(&iser_conn->state_mutex);
 674         /* In case we endup here without ep_disconnect being invoked. */
 675         if (iser_conn->state != ISER_CONN_DOWN) {
 676                 iser_warn("iser conn %p state %d, expected state down.\n",
 677                           iser_conn, iser_conn->state);
 678                 iscsi_destroy_endpoint(iser_conn->ep);
 679                 iser_conn->state = ISER_CONN_DOWN;
 680         }
 681         /*
 682          * In case we never got to bind stage, we still need to
 683          * release IB resources (which is safe to call more than once).
 684          */
 685         iser_free_ib_conn_res(iser_conn, true);
 686         mutex_unlock(&iser_conn->state_mutex);
 687
 688         if (ib_conn->cma_id != NULL) {
 689                 rdma_destroy_id(ib_conn->cma_id);
 690                 ib_conn->cma_id = NULL;
 691         }
 692
 693         kfree(iser_conn);
 694 }
 695
 696 /**
 697  * triggers start of the disconnect procedures and wait for them to be done
 698  * Called with state mutex held
 699  */
 700 int iser_conn_terminate(struct iser_conn *iser_conn)
 701 {
 702         struct ib_conn *ib_conn = &iser_conn->ib_conn;
 703         struct ib_send_wr *bad_wr;
 704         int err = 0;
 705
 706         /* terminate the iser conn only if the conn state is UP */
 707         if (!iser_conn_state_comp_exch(iser_conn, ISER_CONN_UP,
 708                                        ISER_CONN_TERMINATING))
 709                 return 0;
 710
 711         iser_info("iser_conn %p state %d\n", iser_conn, iser_conn->state);
 712
 713         /* suspend queuing of new iscsi commands */
 714         if (iser_conn->iscsi_conn)
 715                 iscsi_suspend_queue(iser_conn->iscsi_conn);
 716
 717         /*
 718          * In case we didn't already clean up the cma_id (peer initiated
 719          * a disconnection), we need to Cause the CMA to change the QP
 720          * state to ERROR.
 721          */
 722         if (ib_conn->cma_id) {
 723                 err = rdma_disconnect(ib_conn->cma_id);
 724                 if (err)
 725                         iser_err("Failed to disconnect, conn: 0x%p err %d\n",
 726                                  iser_conn, err);
 727
 728                 /* post an indication that all flush errors were consumed */
 729                 err = ib_post_send(ib_conn->qp, &ib_conn->beacon, &bad_wr);
 730                 if (err) {
 731                         iser_err("conn %p failed to post beacon", ib_conn);
 732                         return 1;
 733                 }
 734
 735                 wait_for_completion(&ib_conn->flush_comp);
 736         }
 737
 738         return 1;
 739 }
 740
 741 /**
 742  * Called with state mutex held
 743  **/
 744 static void iser_connect_error(struct rdma_cm_id *cma_id)
 745 {
 746         struct iser_conn *iser_conn;
 747
 748         iser_conn = (struct iser_conn *)cma_id->context;
 749         iser_conn->state = ISER_CONN_TERMINATING;
 750 }
 751
 752 static void
 753 iser_calc_scsi_params(struct iser_conn *iser_conn,
 754                       unsigned int max_sectors)
 755 {
 756         struct iser_device *device = iser_conn->ib_conn.device;
 757         unsigned short sg_tablesize, sup_sg_tablesize;
 758
 759         sg_tablesize = DIV_ROUND_UP(max_sectors * 512, SIZE_4K);
 760         sup_sg_tablesize = min_t(unsigned, ISCSI_ISER_MAX_SG_TABLESIZE,
 761                                  device->dev_attr.max_fast_reg_page_list_len);
 762
 763         if (sg_tablesize > sup_sg_tablesize) {
 764                 sg_tablesize = sup_sg_tablesize;
 765                 iser_conn->scsi_max_sectors = sg_tablesize * SIZE_4K / 512;
 766         } else {
 767                 iser_conn->scsi_max_sectors = max_sectors;
 768         }
 769
 770         iser_conn->scsi_sg_tablesize = sg_tablesize;
 771
 772         iser_dbg("iser_conn %p, sg_tablesize %u, max_sectors %u\n",
 773                  iser_conn, iser_conn->scsi_sg_tablesize,
 774                  iser_conn->scsi_max_sectors);
 775 }
 776
 777 /**
 778  * Called with state mutex held
 779  **/
 780 static void iser_addr_handler(struct rdma_cm_id *cma_id)
 781 {
 782         struct iser_device *device;
 783         struct iser_conn   *iser_conn;
 784         struct ib_conn   *ib_conn;
 785         int    ret;
 786
 787         iser_conn = (struct iser_conn *)cma_id->context;
 788         if (iser_conn->state != ISER_CONN_PENDING)
 789                 /* bailout */
 790                 return;
 791
 792         ib_conn = &iser_conn->ib_conn;
 793         device = iser_device_find_by_ib_device(cma_id);
 794         if (!device) {
 795                 iser_err("device lookup/creation failed\n");
 796                 iser_connect_error(cma_id);
 797                 return;
 798         }
 799
 800         ib_conn->device = device;
 801
 802         /* connection T10-PI support */
 803         if (iser_pi_enable) {
 804                 if (!(device->dev_attr.device_cap_flags &
 805                       IB_DEVICE_SIGNATURE_HANDOVER)) {
 806                         iser_warn("T10-PI requested but not supported on %s, "
 807                                   "continue without T10-PI\n",
 808                                   ib_conn->device->ib_device->name);
 809                         ib_conn->pi_support = false;
 810                 } else {
 811                         ib_conn->pi_support = true;
 812                 }
 813         }
 814
 815         iser_calc_scsi_params(iser_conn, iser_max_sectors);
 816
 817         ret = rdma_resolve_route(cma_id, 1000);
 818         if (ret) {
 819                 iser_err("resolve route failed: %d\n", ret);
 820                 iser_connect_error(cma_id);
 821                 return;
 822         }
 823 }
 824
 825 /**
 826  * Called with state mutex held
 827  **/
 828 static void iser_route_handler(struct rdma_cm_id *cma_id)
 829 {
 830         struct rdma_conn_param conn_param;
 831         int    ret;
 832         struct iser_cm_hdr req_hdr;
 833         struct iser_conn *iser_conn = (struct iser_conn *)cma_id->context;
 834         struct ib_conn *ib_conn = &iser_conn->ib_conn;
 835         struct iser_device *device = ib_conn->device;
 836
 837         if (iser_conn->state != ISER_CONN_PENDING)
 838                 /* bailout */
 839                 return;
 840
 841         ret = iser_create_ib_conn_res(ib_conn);
 842         if (ret)
 843                 goto failure;
 844
 845         memset(&conn_param, 0, sizeof conn_param);
 846         conn_param.responder_resources = device->dev_attr.max_qp_rd_atom;
 847         conn_param.initiator_depth     = 1;
 848         conn_param.retry_count         = 7;
 849         conn_param.rnr_retry_count     = 6;
 850
 851         memset(&req_hdr, 0, sizeof(req_hdr));
 852         req_hdr.flags = (ISER_ZBVA_NOT_SUPPORTED |
 853                         ISER_SEND_W_INV_NOT_SUPPORTED);
 854         conn_param.private_data         = (void *)&req_hdr;
 855         conn_param.private_data_len     = sizeof(struct iser_cm_hdr);
 856
 857         ret = rdma_connect(cma_id, &conn_param);
 858         if (ret) {
 859                 iser_err("failure connecting: %d\n", ret);
 860                 goto failure;
 861         }
 862
 863         return;
 864 failure:
 865         iser_connect_error(cma_id);
 866 }
 867
 868 static void iser_connected_handler(struct rdma_cm_id *cma_id)
 869 {
 870         struct iser_conn *iser_conn;
 871         struct ib_qp_attr attr;
 872         struct ib_qp_init_attr init_attr;
 873
 874         iser_conn = (struct iser_conn *)cma_id->context;
 875         if (iser_conn->state != ISER_CONN_PENDING)
 876                 /* bailout */
 877                 return;
 878
 879         (void)ib_query_qp(cma_id->qp, &attr, ~0, &init_attr);
 880         iser_info("remote qpn:%x my qpn:%x\n", attr.dest_qp_num, cma_id->qp->qp_num);
 881
 882         iser_conn->state = ISER_CONN_UP;
 883         complete(&iser_conn->up_completion);
 884 }
 885
 886 static void iser_disconnected_handler(struct rdma_cm_id *cma_id)
 887 {
 888         struct iser_conn *iser_conn = (struct iser_conn *)cma_id->context;
 889
 890         if (iser_conn_terminate(iser_conn)) {
 891                 if (iser_conn->iscsi_conn)
 892                         iscsi_conn_failure(iser_conn->iscsi_conn,
 893                                            ISCSI_ERR_CONN_FAILED);
 894                 else
 895                         iser_err("iscsi_iser connection isn't bound\n");
 896         }
 897 }
 898
 899 static void iser_cleanup_handler(struct rdma_cm_id *cma_id,
 900                                  bool destroy)
 901 {
 902         struct iser_conn *iser_conn = (struct iser_conn *)cma_id->context;
 903
 904         /*
 905          * We are not guaranteed that we visited disconnected_handler
 906          * by now, call it here to be safe that we handle CM drep
 907          * and flush errors.
 908          */
 909         iser_disconnected_handler(cma_id);
 910         iser_free_ib_conn_res(iser_conn, destroy);
 911         complete(&iser_conn->ib_completion);
 912 };
 913
 914 static int iser_cma_handler(struct rdma_cm_id *cma_id, struct rdma_cm_event *event)
 915 {
 916         struct iser_conn *iser_conn;
 917         int ret = 0;
 918
 919         iser_conn = (struct iser_conn *)cma_id->context;
 920         iser_info("%s (%d): status %d conn %p id %p\n",
 921                   rdma_event_msg(event->event), event->event,
 922                   event->status, cma_id->context, cma_id);
 923
 924         mutex_lock(&iser_conn->state_mutex);
 925         switch (event->event) {
 926         case RDMA_CM_EVENT_ADDR_RESOLVED:
 927                 iser_addr_handler(cma_id);
 928                 break;
 929         case RDMA_CM_EVENT_ROUTE_RESOLVED:
 930                 iser_route_handler(cma_id);
 931                 break;
 932         case RDMA_CM_EVENT_ESTABLISHED:
 933                 iser_connected_handler(cma_id);
 934                 break;
 935         case RDMA_CM_EVENT_ADDR_ERROR:
 936         case RDMA_CM_EVENT_ROUTE_ERROR:
 937         case RDMA_CM_EVENT_CONNECT_ERROR:
 938         case RDMA_CM_EVENT_UNREACHABLE:
 939         case RDMA_CM_EVENT_REJECTED:
 940                 iser_connect_error(cma_id);
 941                 break;
 942         case RDMA_CM_EVENT_DISCONNECTED:
 943         case RDMA_CM_EVENT_ADDR_CHANGE:
 944         case RDMA_CM_EVENT_TIMEWAIT_EXIT:
 945                 iser_cleanup_handler(cma_id, false);
 946                 break;
 947         case RDMA_CM_EVENT_DEVICE_REMOVAL:
 948                 /*
 949                  * we *must* destroy the device as we cannot rely
 950                  * on iscsid to be around to initiate error handling.
 951                  * also if we are not in state DOWN implicitly destroy
 952                  * the cma_id.
 953                  */
 954                 iser_cleanup_handler(cma_id, true);
 955                 if (iser_conn->state != ISER_CONN_DOWN) {
 956                         iser_conn->ib_conn.cma_id = NULL;
 957                         ret = 1;
 958                 }
 959                 break;
 960         default:
 961                 iser_err("Unexpected RDMA CM event: %s (%d)\n",
 962                          rdma_event_msg(event->event), event->event);
 963                 break;
 964         }
 965         mutex_unlock(&iser_conn->state_mutex);
 966
 967         return ret;
 968 }
 969
 970 void iser_conn_init(struct iser_conn *iser_conn)
 971 {
 972         iser_conn->state = ISER_CONN_INIT;
 973         iser_conn->ib_conn.post_recv_buf_count = 0;
 974         init_completion(&iser_conn->ib_conn.flush_comp);
 975         init_completion(&iser_conn->stop_completion);
 976         init_completion(&iser_conn->ib_completion);
 977         init_completion(&iser_conn->up_completion);
 978         INIT_LIST_HEAD(&iser_conn->conn_list);
 979         mutex_init(&iser_conn->state_mutex);
 980 }
 981
 982  /**
 983  * starts the process of connecting to the target
 984  * sleeps until the connection is established or rejected
 985  */
 986 int iser_connect(struct iser_conn   *iser_conn,
 987                  struct sockaddr    *src_addr,
 988                  struct sockaddr    *dst_addr,
 989                  int                 non_blocking)
 990 {
 991         struct ib_conn *ib_conn = &iser_conn->ib_conn;
 992         int err = 0;
 993
 994         mutex_lock(&iser_conn->state_mutex);
 995
 996         sprintf(iser_conn->name, "%pISp", dst_addr);
 997
 998         iser_info("connecting to: %s\n", iser_conn->name);
 999
1000         /* the device is known only --after-- address resolution */
1001         ib_conn->device = NULL;
1002
1003         iser_conn->state = ISER_CONN_PENDING;
1004
1005         ib_conn->beacon.wr_id = ISER_BEACON_WRID;
1006         ib_conn->beacon.opcode = IB_WR_SEND;
1007
1008         ib_conn->cma_id = rdma_create_id(&init_net, iser_cma_handler,
1009                                          (void *)iser_conn,
1010                                          RDMA_PS_TCP, IB_QPT_RC);
1011         if (IS_ERR(ib_conn->cma_id)) {
1012                 err = PTR_ERR(ib_conn->cma_id);
1013                 iser_err("rdma_create_id failed: %d\n", err);
1014                 goto id_failure;
1015         }
1016
1017         err = rdma_resolve_addr(ib_conn->cma_id, src_addr, dst_addr, 1000);
1018         if (err) {
1019                 iser_err("rdma_resolve_addr failed: %d\n", err);
1020                 goto addr_failure;
1021         }
1022
1023         if (!non_blocking) {
1024                 wait_for_completion_interruptible(&iser_conn->up_completion);
1025
1026                 if (iser_conn->state != ISER_CONN_UP) {
1027                         err =  -EIO;
1028                         goto connect_failure;
1029                 }
1030         }
1031         mutex_unlock(&iser_conn->state_mutex);
1032
1033         mutex_lock(&ig.connlist_mutex);
1034         list_add(&iser_conn->conn_list, &ig.connlist);
1035         mutex_unlock(&ig.connlist_mutex);
1036         return 0;
1037
1038 id_failure:
1039         ib_conn->cma_id = NULL;
1040 addr_failure:
1041         iser_conn->state = ISER_CONN_DOWN;
1042 connect_failure:
1043         mutex_unlock(&iser_conn->state_mutex);
1044         iser_conn_release(iser_conn);
1045         return err;
1046 }
1047
1048 int iser_post_recvl(struct iser_conn *iser_conn)
1049 {
1050         struct ib_recv_wr rx_wr, *rx_wr_failed;
1051         struct ib_conn *ib_conn = &iser_conn->ib_conn;
1052         struct ib_sge     sge;
1053         int ib_ret;
1054
1055         sge.addr   = iser_conn->login_resp_dma;
1056         sge.length = ISER_RX_LOGIN_SIZE;
1057         sge.lkey   = ib_conn->device->pd->local_dma_lkey;
1058
1059         rx_wr.wr_id   = (uintptr_t)iser_conn->login_resp_buf;
1060         rx_wr.sg_list = &sge;
1061         rx_wr.num_sge = 1;
1062         rx_wr.next    = NULL;
1063
1064         ib_conn->post_recv_buf_count++;
1065         ib_ret  = ib_post_recv(ib_conn->qp, &rx_wr, &rx_wr_failed);
1066         if (ib_ret) {
1067                 iser_err("ib_post_recv failed ret=%d\n", ib_ret);
1068                 ib_conn->post_recv_buf_count--;
1069         }
1070         return ib_ret;
1071 }
1072
1073 int iser_post_recvm(struct iser_conn *iser_conn, int count)
1074 {
1075         struct ib_recv_wr *rx_wr, *rx_wr_failed;
1076         int i, ib_ret;
1077         struct ib_conn *ib_conn = &iser_conn->ib_conn;
1078         unsigned int my_rx_head = iser_conn->rx_desc_head;
1079         struct iser_rx_desc *rx_desc;
1080
1081         for (rx_wr = ib_conn->rx_wr, i = 0; i < count; i++, rx_wr++) {
1082                 rx_desc         = &iser_conn->rx_descs[my_rx_head];
1083                 rx_wr->wr_id    = (uintptr_t)rx_desc;
1084                 rx_wr->sg_list  = &rx_desc->rx_sg;
1085                 rx_wr->num_sge  = 1;
1086                 rx_wr->next     = rx_wr + 1;
1087                 my_rx_head = (my_rx_head + 1) & iser_conn->qp_max_recv_dtos_mask;
1088         }
1089
1090         rx_wr--;
1091         rx_wr->next = NULL; /* mark end of work requests list */
1092
1093         ib_conn->post_recv_buf_count += count;
1094         ib_ret  = ib_post_recv(ib_conn->qp, ib_conn->rx_wr, &rx_wr_failed);
1095         if (ib_ret) {
1096                 iser_err("ib_post_recv failed ret=%d\n", ib_ret);
1097                 ib_conn->post_recv_buf_count -= count;
1098         } else
1099                 iser_conn->rx_desc_head = my_rx_head;
1100         return ib_ret;
1101 }
1102
1103
1104 /**
1105  * iser_start_send - Initiate a Send DTO operation
1106  *
1107  * returns 0 on success, -1 on failure
1108  */
1109 int iser_post_send(struct ib_conn *ib_conn, struct iser_tx_desc *tx_desc,
1110                    bool signal)
1111 {
1112         struct ib_send_wr *bad_wr, *wr = iser_tx_next_wr(tx_desc);
1113         int ib_ret;
1114
1115         ib_dma_sync_single_for_device(ib_conn->device->ib_device,
1116                                       tx_desc->dma_addr, ISER_HEADERS_LEN,
1117                                       DMA_TO_DEVICE);
1118
1119         wr->next = NULL;
1120         wr->wr_id = (uintptr_t)tx_desc;
1121         wr->sg_list = tx_desc->tx_sg;
1122         wr->num_sge = tx_desc->num_sge;
1123         wr->opcode = IB_WR_SEND;
1124         wr->send_flags = signal ? IB_SEND_SIGNALED : 0;
1125
1126         ib_ret = ib_post_send(ib_conn->qp, &tx_desc->wrs[0].send, &bad_wr);
1127         if (ib_ret)
1128                 iser_err("ib_post_send failed, ret:%d opcode:%d\n",
1129                          ib_ret, bad_wr->opcode);
1130
1131         return ib_ret;
1132 }
1133
1134 /**
1135  * is_iser_tx_desc - Indicate if the completion wr_id
1136  *     is a TX descriptor or not.
1137  * @iser_conn: iser connection
1138  * @wr_id: completion WR identifier
1139  *
1140  * Since we cannot rely on wc opcode in FLUSH errors
1141  * we must work around it by checking if the wr_id address
1142  * falls in the iser connection rx_descs buffer. If so
1143  * it is an RX descriptor, otherwize it is a TX.
1144  */
1145 static inline bool
1146 is_iser_tx_desc(struct iser_conn *iser_conn, void *wr_id)
1147 {
1148         void *start = iser_conn->rx_descs;
1149         int len = iser_conn->num_rx_descs * sizeof(*iser_conn->rx_descs);
1150
1151         if (wr_id >= start && wr_id < start + len)
1152                 return false;
1153
1154         return true;
1155 }
1156
1157 /**
1158  * iser_handle_comp_error() - Handle error completion
1159  * @ib_conn:   connection RDMA resources
1160  * @wc:        work completion
1161  *
1162  * Notes: We may handle a FLUSH error completion and in this case
1163  *        we only cleanup in case TX type was DATAOUT. For non-FLUSH
1164  *        error completion we should also notify iscsi layer that
1165  *        connection is failed (in case we passed bind stage).
1166  */
1167 static void
1168 iser_handle_comp_error(struct ib_conn *ib_conn,
1169                        struct ib_wc *wc)
1170 {
1171         void *wr_id = (void *)(uintptr_t)wc->wr_id;
1172         struct iser_conn *iser_conn = container_of(ib_conn, struct iser_conn,
1173                                                    ib_conn);
1174
1175         if (wc->status != IB_WC_WR_FLUSH_ERR)
1176                 if (iser_conn->iscsi_conn)
1177                         iscsi_conn_failure(iser_conn->iscsi_conn,
1178                                            ISCSI_ERR_CONN_FAILED);
1179
1180         if (wc->wr_id == ISER_FASTREG_LI_WRID)
1181                 return;
1182
1183         if (is_iser_tx_desc(iser_conn, wr_id)) {
1184                 struct iser_tx_desc *desc = wr_id;
1185
1186                 if (desc->type == ISCSI_TX_DATAOUT)
1187                         kmem_cache_free(ig.desc_cache, desc);
1188         } else {
1189                 ib_conn->post_recv_buf_count--;
1190         }
1191 }
1192
1193 /**
1194  * iser_handle_wc - handle a single work completion
1195  * @wc: work completion
1196  *
1197  * Soft-IRQ context, work completion can be either
1198  * SEND or RECV, and can turn out successful or
1199  * with error (or flush error).
1200  */
1201 static void iser_handle_wc(struct ib_wc *wc)
1202 {
1203         struct ib_conn *ib_conn;
1204         struct iser_tx_desc *tx_desc;
1205         struct iser_rx_desc *rx_desc;
1206
1207         ib_conn = wc->qp->qp_context;
1208         if (likely(wc->status == IB_WC_SUCCESS)) {
1209                 if (wc->opcode == IB_WC_RECV) {
1210                         rx_desc = (struct iser_rx_desc *)(uintptr_t)wc->wr_id;
1211                         iser_rcv_completion(rx_desc, wc->byte_len,
1212                                             ib_conn);
1213                 } else
1214                 if (wc->opcode == IB_WC_SEND) {
1215                         tx_desc = (struct iser_tx_desc *)(uintptr_t)wc->wr_id;
1216                         iser_snd_completion(tx_desc, ib_conn);
1217                 } else {
1218                         iser_err("Unknown wc opcode %d\n", wc->opcode);
1219                 }
1220         } else {
1221                 if (wc->status != IB_WC_WR_FLUSH_ERR)
1222                         iser_err("%s (%d): wr id %llx vend_err %x\n",
1223                                  ib_wc_status_msg(wc->status), wc->status,
1224                                  wc->wr_id, wc->vendor_err);
1225                 else
1226                         iser_dbg("%s (%d): wr id %llx\n",
1227                                  ib_wc_status_msg(wc->status), wc->status,
1228                                  wc->wr_id);
1229
1230                 if (wc->wr_id == ISER_BEACON_WRID)
1231                         /* all flush errors were consumed */
1232                         complete(&ib_conn->flush_comp);
1233                 else
1234                         iser_handle_comp_error(ib_conn, wc);
1235         }
1236 }
1237
1238 /**
1239  * iser_cq_tasklet_fn - iSER completion polling loop
1240  * @data: iSER completion context
1241  *
1242  * Soft-IRQ context, polling connection CQ until
1243  * either CQ was empty or we exausted polling budget
1244  */
1245 static void iser_cq_tasklet_fn(unsigned long data)
1246 {
1247         struct iser_comp *comp = (struct iser_comp *)data;
1248         struct ib_cq *cq = comp->cq;
1249         struct ib_wc *const wcs = comp->wcs;
1250         int i, n, completed = 0;
1251
1252         while ((n = ib_poll_cq(cq, ARRAY_SIZE(comp->wcs), wcs)) > 0) {
1253                 for (i = 0; i < n; i++)
1254                         iser_handle_wc(&wcs[i]);
1255
1256                 completed += n;
1257                 if (completed >= iser_cq_poll_limit)
1258                         break;
1259         }
1260
1261         /*
1262          * It is assumed here that arming CQ only once its empty
1263          * would not cause interrupts to be missed.
1264          */
1265         ib_req_notify_cq(cq, IB_CQ_NEXT_COMP);
1266
1267         iser_dbg("got %d completions\n", completed);
1268 }
1269
1270 static void iser_cq_callback(struct ib_cq *cq, void *cq_context)
1271 {
1272         struct iser_comp *comp = cq_context;
1273
1274         tasklet_schedule(&comp->tasklet);
1275 }
1276
1277 u8 iser_check_task_pi_status(struct iscsi_iser_task *iser_task,
1278                              enum iser_data_dir cmd_dir, sector_t *sector)
1279 {
1280         struct iser_mem_reg *reg = &iser_task->rdma_reg[cmd_dir];
1281         struct iser_fr_desc *desc = reg->mem_h;
1282         unsigned long sector_size = iser_task->sc->device->sector_size;
1283         struct ib_mr_status mr_status;
1284         int ret;
1285
1286         if (desc && desc->pi_ctx->sig_protected) {
1287                 desc->pi_ctx->sig_protected = 0;
1288                 ret = ib_check_mr_status(desc->pi_ctx->sig_mr,
1289                                          IB_MR_CHECK_SIG_STATUS, &mr_status);
1290                 if (ret) {
1291                         pr_err("ib_check_mr_status failed, ret %d\n", ret);
1292                         /* Not a lot we can do, return ambiguous guard error */
1293                         *sector = 0;
1294                         return 0x1;
1295                 }
1296
1297                 if (mr_status.fail_status & IB_MR_CHECK_SIG_STATUS) {
1298                         sector_t sector_off = mr_status.sig_err.sig_err_offset;
1299
1300                         sector_div(sector_off, sector_size + 8);
1301                         *sector = scsi_get_lba(iser_task->sc) + sector_off;
1302
1303                         pr_err("PI error found type %d at sector %llx "
1304                                "expected %x vs actual %x\n",
1305                                mr_status.sig_err.err_type,
1306                                (unsigned long long)*sector,
1307                                mr_status.sig_err.expected,
1308                                mr_status.sig_err.actual);
1309
1310                         switch (mr_status.sig_err.err_type) {
1311                         case IB_SIG_BAD_GUARD:
1312                                 return 0x1;
1313                         case IB_SIG_BAD_REFTAG:
1314                                 return 0x3;
1315                         case IB_SIG_BAD_APPTAG:
1316                                 return 0x2;
1317                         }
1318                 }
1319         }
1320
1321         return 0;
1322 }