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ib_srp.c

/*
 * Copyright (c) 2005 Cisco Systems.  All rights reserved.
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the
 * OpenIB.org BSD license below:
 *
 *     Redistribution and use in source and binary forms, with or
 *     without modification, are permitted provided that the following
 *     conditions are met:
 *
 *      - Redistributions of source code must retain the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer.
 *
 *      - Redistributions in binary form must reproduce the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer in the documentation and/or other materials
 *        provided with the distribution.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 *
 * $Id: ib_srp.c 3932 2005-11-01 17:19:29Z roland $
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/string.h>
#include <linux/parser.h>
#include <linux/random.h>
#include <linux/jiffies.h>

#include <asm/atomic.h>

#include <scsi/scsi.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_dbg.h>
#include <scsi/srp.h>
#include <scsi/scsi_transport_srp.h>

#include <rdma/ib_cache.h>

#include "ib_srp.h"

#define DRV_NAME  "ib_srp"
#define PFX       DRV_NAME ": "
#define DRV_VERSION     "0.2"
#define DRV_RELDATE     "November 1, 2005"

MODULE_AUTHOR("Roland Dreier");
MODULE_DESCRIPTION("InfiniBand SCSI RDMA Protocol initiator "
               "v" DRV_VERSION " (" DRV_RELDATE ")");
MODULE_LICENSE("Dual BSD/GPL");

static int srp_sg_tablesize = SRP_DEF_SG_TABLESIZE;
static int srp_max_iu_len;

module_param(srp_sg_tablesize, int, 0444);
MODULE_PARM_DESC(srp_sg_tablesize,
             "Max number of gather/scatter entries per I/O (default is 12)");

static int topspin_workarounds = 1;

module_param(topspin_workarounds, int, 0444);
MODULE_PARM_DESC(topspin_workarounds,
             "Enable workarounds for Topspin/Cisco SRP target bugs if != 0");

static int mellanox_workarounds = 1;

module_param(mellanox_workarounds, int, 0444);
MODULE_PARM_DESC(mellanox_workarounds,
             "Enable workarounds for Mellanox SRP target bugs if != 0");

static void srp_add_one(struct ib_device *device);
static void srp_remove_one(struct ib_device *device);
static void srp_completion(struct ib_cq *cq, void *target_ptr);
static int srp_cm_handler(struct ib_cm_id *cm_id, struct ib_cm_event *event);

static struct scsi_transport_template *ib_srp_transport_template;

static struct ib_client srp_client = {
      .name   = "srp",
      .add    = srp_add_one,
      .remove = srp_remove_one
};

static struct ib_sa_client srp_sa_client;

static inline struct srp_target_port *host_to_target(struct Scsi_Host *host)
{
      return (struct srp_target_port *) host->hostdata;
}

static const char *srp_target_info(struct Scsi_Host *host)
{
      return host_to_target(host)->target_name;
}

static int srp_target_is_topspin(struct srp_target_port *target)
{
      static const u8 topspin_oui[3] = { 0x00, 0x05, 0xad };
      static const u8 cisco_oui[3]   = { 0x00, 0x1b, 0x0d };

      return topspin_workarounds &&
            (!memcmp(&target->ioc_guid, topspin_oui, sizeof topspin_oui) ||
             !memcmp(&target->ioc_guid, cisco_oui, sizeof cisco_oui));
}

static int srp_target_is_mellanox(struct srp_target_port *target)
{
      static const u8 mellanox_oui[3] = { 0x00, 0x02, 0xc9 };

      return mellanox_workarounds &&
            !memcmp(&target->ioc_guid, mellanox_oui, sizeof mellanox_oui);
}

static struct srp_iu *srp_alloc_iu(struct srp_host *host, size_t size,
                           gfp_t gfp_mask,
                           enum dma_data_direction direction)
{
      struct srp_iu *iu;

      iu = kmalloc(sizeof *iu, gfp_mask);
      if (!iu)
            goto out;

      iu->buf = kzalloc(size, gfp_mask);
      if (!iu->buf)
            goto out_free_iu;

      iu->dma = ib_dma_map_single(host->dev->dev, iu->buf, size, direction);
      if (ib_dma_mapping_error(host->dev->dev, iu->dma))
            goto out_free_buf;

      iu->size      = size;
      iu->direction = direction;

      return iu;

out_free_buf:
      kfree(iu->buf);
out_free_iu:
      kfree(iu);
out:
      return NULL;
}

static void srp_free_iu(struct srp_host *host, struct srp_iu *iu)
{
      if (!iu)
            return;

      ib_dma_unmap_single(host->dev->dev, iu->dma, iu->size, iu->direction);
      kfree(iu->buf);
      kfree(iu);
}

static void srp_qp_event(struct ib_event *event, void *context)
{
      printk(KERN_ERR PFX "QP event %d\n", event->event);
}

static int srp_init_qp(struct srp_target_port *target,
                   struct ib_qp *qp)
{
      struct ib_qp_attr *attr;
      int ret;

      attr = kmalloc(sizeof *attr, GFP_KERNEL);
      if (!attr)
            return -ENOMEM;

      ret = ib_find_cached_pkey(target->srp_host->dev->dev,
                          target->srp_host->port,
                          be16_to_cpu(target->path.pkey),
                          &attr->pkey_index);
      if (ret)
            goto out;

      attr->qp_state        = IB_QPS_INIT;
      attr->qp_access_flags = (IB_ACCESS_REMOTE_READ |
                            IB_ACCESS_REMOTE_WRITE);
      attr->port_num        = target->srp_host->port;

      ret = ib_modify_qp(qp, attr,
                     IB_QP_STATE          |
                     IB_QP_PKEY_INDEX     |
                     IB_QP_ACCESS_FLAGS   |
                     IB_QP_PORT);

out:
      kfree(attr);
      return ret;
}

static int srp_create_target_ib(struct srp_target_port *target)
{
      struct ib_qp_init_attr *init_attr;
      int ret;

      init_attr = kzalloc(sizeof *init_attr, GFP_KERNEL);
      if (!init_attr)
            return -ENOMEM;

      target->cq = ib_create_cq(target->srp_host->dev->dev, srp_completion,
                          NULL, target, SRP_CQ_SIZE, 0);
      if (IS_ERR(target->cq)) {
            ret = PTR_ERR(target->cq);
            goto out;
      }

      ib_req_notify_cq(target->cq, IB_CQ_NEXT_COMP);

      init_attr->event_handler       = srp_qp_event;
      init_attr->cap.max_send_wr     = SRP_SQ_SIZE;
      init_attr->cap.max_recv_wr     = SRP_RQ_SIZE;
      init_attr->cap.max_recv_sge    = 1;
      init_attr->cap.max_send_sge    = 1;
      init_attr->sq_sig_type         = IB_SIGNAL_ALL_WR;
      init_attr->qp_type             = IB_QPT_RC;
      init_attr->send_cq             = target->cq;
      init_attr->recv_cq             = target->cq;

      target->qp = ib_create_qp(target->srp_host->dev->pd, init_attr);
      if (IS_ERR(target->qp)) {
            ret = PTR_ERR(target->qp);
            ib_destroy_cq(target->cq);
            goto out;
      }

      ret = srp_init_qp(target, target->qp);
      if (ret) {
            ib_destroy_qp(target->qp);
            ib_destroy_cq(target->cq);
            goto out;
      }

out:
      kfree(init_attr);
      return ret;
}

static void srp_free_target_ib(struct srp_target_port *target)
{
      int i;

      ib_destroy_qp(target->qp);
      ib_destroy_cq(target->cq);

      for (i = 0; i < SRP_RQ_SIZE; ++i)
            srp_free_iu(target->srp_host, target->rx_ring[i]);
      for (i = 0; i < SRP_SQ_SIZE + 1; ++i)
            srp_free_iu(target->srp_host, target->tx_ring[i]);
}

static void srp_path_rec_completion(int status,
                            struct ib_sa_path_rec *pathrec,
                            void *target_ptr)
{
      struct srp_target_port *target = target_ptr;

      target->status = status;
      if (status)
            printk(KERN_ERR PFX "Got failed path rec status %d\n", status);
      else
            target->path = *pathrec;
      complete(&target->done);
}

static int srp_lookup_path(struct srp_target_port *target)
{
      target->path.numb_path = 1;

      init_completion(&target->done);

      target->path_query_id = ib_sa_path_rec_get(&srp_sa_client,
                                       target->srp_host->dev->dev,
                                       target->srp_host->port,
                                       &target->path,
                                       IB_SA_PATH_REC_SERVICE_ID  |
                                       IB_SA_PATH_REC_DGID        |
                                       IB_SA_PATH_REC_SGID        |
                                       IB_SA_PATH_REC_NUMB_PATH   |
                                       IB_SA_PATH_REC_PKEY,
                                       SRP_PATH_REC_TIMEOUT_MS,
                                       GFP_KERNEL,
                                       srp_path_rec_completion,
                                       target, &target->path_query);
      if (target->path_query_id < 0)
            return target->path_query_id;

      wait_for_completion(&target->done);

      if (target->status < 0)
            printk(KERN_WARNING PFX "Path record query failed\n");

      return target->status;
}

static int srp_send_req(struct srp_target_port *target)
{
      struct {
            struct ib_cm_req_param param;
            struct srp_login_req   priv;
      } *req = NULL;
      int status;

      req = kzalloc(sizeof *req, GFP_KERNEL);
      if (!req)
            return -ENOMEM;

      req->param.primary_path             = &target->path;
      req->param.alternate_path           = NULL;
      req->param.service_id               = target->service_id;
      req->param.qp_num                   = target->qp->qp_num;
      req->param.qp_type                  = target->qp->qp_type;
      req->param.private_data             = &req->priv;
      req->param.private_data_len         = sizeof req->priv;
      req->param.flow_control             = 1;

      get_random_bytes(&req->param.starting_psn, 4);
      req->param.starting_psn            &= 0xffffff;

      /*
       * Pick some arbitrary defaults here; we could make these
       * module parameters if anyone cared about setting them.
       */
      req->param.responder_resources            = 4;
      req->param.remote_cm_response_timeout = 20;
      req->param.local_cm_response_timeout  = 20;
      req->param.retry_count              = 7;
      req->param.rnr_retry_count          = 7;
      req->param.max_cm_retries           = 15;

      req->priv.opcode        = SRP_LOGIN_REQ;
      req->priv.tag           = 0;
      req->priv.req_it_iu_len = cpu_to_be32(srp_max_iu_len);
      req->priv.req_buf_fmt   = cpu_to_be16(SRP_BUF_FORMAT_DIRECT |
                                    SRP_BUF_FORMAT_INDIRECT);
      /*
       * In the published SRP specification (draft rev. 16a), the
       * port identifier format is 8 bytes of ID extension followed
       * by 8 bytes of GUID.  Older drafts put the two halves in the
       * opposite order, so that the GUID comes first.
       *
       * Targets conforming to these obsolete drafts can be
       * recognized by the I/O Class they report.
       */
      if (target->io_class == SRP_REV10_IB_IO_CLASS) {
            memcpy(req->priv.initiator_port_id,
                   &target->path.sgid.global.interface_id, 8);
            memcpy(req->priv.initiator_port_id + 8,
                   &target->initiator_ext, 8);
            memcpy(req->priv.target_port_id,     &target->ioc_guid, 8);
            memcpy(req->priv.target_port_id + 8, &target->id_ext, 8);
      } else {
            memcpy(req->priv.initiator_port_id,
                   &target->initiator_ext, 8);
            memcpy(req->priv.initiator_port_id + 8,
                   &target->path.sgid.global.interface_id, 8);
            memcpy(req->priv.target_port_id,     &target->id_ext, 8);
            memcpy(req->priv.target_port_id + 8, &target->ioc_guid, 8);
      }

      /*
       * Topspin/Cisco SRP targets will reject our login unless we
       * zero out the first 8 bytes of our initiator port ID and set
       * the second 8 bytes to the local node GUID.
       */
      if (srp_target_is_topspin(target)) {
            printk(KERN_DEBUG PFX "Topspin/Cisco initiator port ID workaround "
                   "activated for target GUID %016llx\n",
                   (unsigned long long) be64_to_cpu(target->ioc_guid));
            memset(req->priv.initiator_port_id, 0, 8);
            memcpy(req->priv.initiator_port_id + 8,
                   &target->srp_host->dev->dev->node_guid, 8);
      }

      status = ib_send_cm_req(target->cm_id, &req->param);

      kfree(req);

      return status;
}

static void srp_disconnect_target(struct srp_target_port *target)
{
      /* XXX should send SRP_I_LOGOUT request */

      init_completion(&target->done);
      if (ib_send_cm_dreq(target->cm_id, NULL, 0)) {
            printk(KERN_DEBUG PFX "Sending CM DREQ failed\n");
            return;
      }
      wait_for_completion(&target->done);
}

static void srp_remove_work(struct work_struct *work)
{
      struct srp_target_port *target =
            container_of(work, struct srp_target_port, work);

      spin_lock_irq(target->scsi_host->host_lock);
      if (target->state != SRP_TARGET_DEAD) {
            spin_unlock_irq(target->scsi_host->host_lock);
            return;
      }
      target->state = SRP_TARGET_REMOVED;
      spin_unlock_irq(target->scsi_host->host_lock);

      spin_lock(&target->srp_host->target_lock);
      list_del(&target->list);
      spin_unlock(&target->srp_host->target_lock);

      srp_remove_host(target->scsi_host);
      scsi_remove_host(target->scsi_host);
      ib_destroy_cm_id(target->cm_id);
      srp_free_target_ib(target);
      scsi_host_put(target->scsi_host);
}

static int srp_connect_target(struct srp_target_port *target)
{
      int ret;

      ret = srp_lookup_path(target);
      if (ret)
            return ret;

      while (1) {
            init_completion(&target->done);
            ret = srp_send_req(target);
            if (ret)
                  return ret;
            wait_for_completion(&target->done);

            /*
             * The CM event handling code will set status to
             * SRP_PORT_REDIRECT if we get a port redirect REJ
             * back, or SRP_DLID_REDIRECT if we get a lid/qp
             * redirect REJ back.
             */
            switch (target->status) {
            case 0:
                  return 0;

            case SRP_PORT_REDIRECT:
                  ret = srp_lookup_path(target);
                  if (ret)
                        return ret;
                  break;

            case SRP_DLID_REDIRECT:
                  break;

            default:
                  return target->status;
            }
      }
}

static void srp_unmap_data(struct scsi_cmnd *scmnd,
                     struct srp_target_port *target,
                     struct srp_request *req)
{
      if (!scsi_sglist(scmnd) ||
          (scmnd->sc_data_direction != DMA_TO_DEVICE &&
           scmnd->sc_data_direction != DMA_FROM_DEVICE))
            return;

      if (req->fmr) {
            ib_fmr_pool_unmap(req->fmr);
            req->fmr = NULL;
      }

      ib_dma_unmap_sg(target->srp_host->dev->dev, scsi_sglist(scmnd),
                  scsi_sg_count(scmnd), scmnd->sc_data_direction);
}

static void srp_remove_req(struct srp_target_port *target, struct srp_request *req)
{
      srp_unmap_data(req->scmnd, target, req);
      list_move_tail(&req->list, &target->free_reqs);
}

static void srp_reset_req(struct srp_target_port *target, struct srp_request *req)
{
      req->scmnd->result = DID_RESET << 16;
      req->scmnd->scsi_done(req->scmnd);
      srp_remove_req(target, req);
}

static int srp_reconnect_target(struct srp_target_port *target)
{
      struct ib_cm_id *new_cm_id;
      struct ib_qp_attr qp_attr;
      struct srp_request *req, *tmp;
      struct ib_wc wc;
      int ret;

      spin_lock_irq(target->scsi_host->host_lock);
      if (target->state != SRP_TARGET_LIVE) {
            spin_unlock_irq(target->scsi_host->host_lock);
            return -EAGAIN;
      }
      target->state = SRP_TARGET_CONNECTING;
      spin_unlock_irq(target->scsi_host->host_lock);

      srp_disconnect_target(target);
      /*
       * Now get a new local CM ID so that we avoid confusing the
       * target in case things are really fouled up.
       */
      new_cm_id = ib_create_cm_id(target->srp_host->dev->dev,
                            srp_cm_handler, target);
      if (IS_ERR(new_cm_id)) {
            ret = PTR_ERR(new_cm_id);
            goto err;
      }
      ib_destroy_cm_id(target->cm_id);
      target->cm_id = new_cm_id;

      qp_attr.qp_state = IB_QPS_RESET;
      ret = ib_modify_qp(target->qp, &qp_attr, IB_QP_STATE);
      if (ret)
            goto err;

      ret = srp_init_qp(target, target->qp);
      if (ret)
            goto err;

      while (ib_poll_cq(target->cq, 1, &wc) > 0)
            ; /* nothing */

      spin_lock_irq(target->scsi_host->host_lock);
      list_for_each_entry_safe(req, tmp, &target->req_queue, list)
            srp_reset_req(target, req);
      spin_unlock_irq(target->scsi_host->host_lock);

      target->rx_head    = 0;
      target->tx_head    = 0;
      target->tx_tail  = 0;

      target->qp_in_error = 0;
      ret = srp_connect_target(target);
      if (ret)
            goto err;

      spin_lock_irq(target->scsi_host->host_lock);
      if (target->state == SRP_TARGET_CONNECTING) {
            ret = 0;
            target->state = SRP_TARGET_LIVE;
      } else
            ret = -EAGAIN;
      spin_unlock_irq(target->scsi_host->host_lock);

      return ret;

err:
      printk(KERN_ERR PFX "reconnect failed (%d), removing target port.\n", ret);

      /*
       * We couldn't reconnect, so kill our target port off.
       * However, we have to defer the real removal because we might
       * be in the context of the SCSI error handler now, which
       * would deadlock if we call scsi_remove_host().
       */
      spin_lock_irq(target->scsi_host->host_lock);
      if (target->state == SRP_TARGET_CONNECTING) {
            target->state = SRP_TARGET_DEAD;
            INIT_WORK(&target->work, srp_remove_work);
            schedule_work(&target->work);
      }
      spin_unlock_irq(target->scsi_host->host_lock);

      return ret;
}

static int srp_map_fmr(struct srp_target_port *target, struct scatterlist *scat,
                   int sg_cnt, struct srp_request *req,
                   struct srp_direct_buf *buf)
{
      u64 io_addr = 0;
      u64 *dma_pages;
      u32 len;
      int page_cnt;
      int i, j;
      int ret;
      struct srp_device *dev = target->srp_host->dev;
      struct ib_device *ibdev = dev->dev;
      struct scatterlist *sg;

      if (!dev->fmr_pool)
            return -ENODEV;

      if (srp_target_is_mellanox(target) &&
          (ib_sg_dma_address(ibdev, &scat[0]) & ~dev->fmr_page_mask))
            return -EINVAL;

      len = page_cnt = 0;
      scsi_for_each_sg(req->scmnd, sg, sg_cnt, i) {
            unsigned int dma_len = ib_sg_dma_len(ibdev, sg);

            if (ib_sg_dma_address(ibdev, sg) & ~dev->fmr_page_mask) {
                  if (i > 0)
                        return -EINVAL;
                  else
                        ++page_cnt;
            }
            if ((ib_sg_dma_address(ibdev, sg) + dma_len) &
                ~dev->fmr_page_mask) {
                  if (i < sg_cnt - 1)
                        return -EINVAL;
                  else
                        ++page_cnt;
            }

            len += dma_len;
      }

      page_cnt += len >> dev->fmr_page_shift;
      if (page_cnt > SRP_FMR_SIZE)
            return -ENOMEM;

      dma_pages = kmalloc(sizeof (u64) * page_cnt, GFP_ATOMIC);
      if (!dma_pages)
            return -ENOMEM;

      page_cnt = 0;
      scsi_for_each_sg(req->scmnd, sg, sg_cnt, i) {
            unsigned int dma_len = ib_sg_dma_len(ibdev, sg);

            for (j = 0; j < dma_len; j += dev->fmr_page_size)
                  dma_pages[page_cnt++] =
                        (ib_sg_dma_address(ibdev, sg) &
                         dev->fmr_page_mask) + j;
      }

      req->fmr = ib_fmr_pool_map_phys(dev->fmr_pool,
                              dma_pages, page_cnt, io_addr);
      if (IS_ERR(req->fmr)) {
            ret = PTR_ERR(req->fmr);
            req->fmr = NULL;
            goto out;
      }

      buf->va  = cpu_to_be64(ib_sg_dma_address(ibdev, &scat[0]) &
                         ~dev->fmr_page_mask);
      buf->key = cpu_to_be32(req->fmr->fmr->rkey);
      buf->len = cpu_to_be32(len);

      ret = 0;

out:
      kfree(dma_pages);

      return ret;
}

static int srp_map_data(struct scsi_cmnd *scmnd, struct srp_target_port *target,
                  struct srp_request *req)
{
      struct scatterlist *scat;
      struct srp_cmd *cmd = req->cmd->buf;
      int len, nents, count;
      u8 fmt = SRP_DATA_DESC_DIRECT;
      struct srp_device *dev;
      struct ib_device *ibdev;

      if (!scsi_sglist(scmnd) || scmnd->sc_data_direction == DMA_NONE)
            return sizeof (struct srp_cmd);

      if (scmnd->sc_data_direction != DMA_FROM_DEVICE &&
          scmnd->sc_data_direction != DMA_TO_DEVICE) {
            printk(KERN_WARNING PFX "Unhandled data direction %d\n",
                   scmnd->sc_data_direction);
            return -EINVAL;
      }

      nents = scsi_sg_count(scmnd);
      scat  = scsi_sglist(scmnd);

      dev = target->srp_host->dev;
      ibdev = dev->dev;

      count = ib_dma_map_sg(ibdev, scat, nents, scmnd->sc_data_direction);

      fmt = SRP_DATA_DESC_DIRECT;
      len = sizeof (struct srp_cmd) +     sizeof (struct srp_direct_buf);

      if (count == 1) {
            /*
             * The midlayer only generated a single gather/scatter
             * entry, or DMA mapping coalesced everything to a
             * single entry.  So a direct descriptor along with
             * the DMA MR suffices.
             */
            struct srp_direct_buf *buf = (void *) cmd->add_data;

            buf->va  = cpu_to_be64(ib_sg_dma_address(ibdev, scat));
            buf->key = cpu_to_be32(dev->mr->rkey);
            buf->len = cpu_to_be32(ib_sg_dma_len(ibdev, scat));
      } else if (srp_map_fmr(target, scat, count, req,
                         (void *) cmd->add_data)) {
            /*
             * FMR mapping failed, and the scatterlist has more
             * than one entry.  Generate an indirect memory
             * descriptor.
             */
            struct srp_indirect_buf *buf = (void *) cmd->add_data;
            struct scatterlist *sg;
            u32 datalen = 0;
            int i;

            fmt = SRP_DATA_DESC_INDIRECT;
            len = sizeof (struct srp_cmd) +
                  sizeof (struct srp_indirect_buf) +
                  count * sizeof (struct srp_direct_buf);

            scsi_for_each_sg(scmnd, sg, count, i) {
                  unsigned int dma_len = ib_sg_dma_len(ibdev, sg);

                  buf->desc_list[i].va  =
                        cpu_to_be64(ib_sg_dma_address(ibdev, sg));
                  buf->desc_list[i].key =
                        cpu_to_be32(dev->mr->rkey);
                  buf->desc_list[i].len = cpu_to_be32(dma_len);
                  datalen += dma_len;
            }

            if (scmnd->sc_data_direction == DMA_TO_DEVICE)
                  cmd->data_out_desc_cnt = count;
            else
                  cmd->data_in_desc_cnt = count;

            buf->table_desc.va  =
                  cpu_to_be64(req->cmd->dma + sizeof *cmd + sizeof *buf);
            buf->table_desc.key =
                  cpu_to_be32(target->srp_host->dev->mr->rkey);
            buf->table_desc.len =
                  cpu_to_be32(count * sizeof (struct srp_direct_buf));

            buf->len = cpu_to_be32(datalen);
      }

      if (scmnd->sc_data_direction == DMA_TO_DEVICE)
            cmd->buf_fmt = fmt << 4;
      else
            cmd->buf_fmt = fmt;

      return len;
}

static void srp_process_rsp(struct srp_target_port *target, struct srp_rsp *rsp)
{
      struct srp_request *req;
      struct scsi_cmnd *scmnd;
      unsigned long flags;
      s32 delta;

      delta = (s32) be32_to_cpu(rsp->req_lim_delta);

      spin_lock_irqsave(target->scsi_host->host_lock, flags);

      target->req_lim += delta;

      req = &target->req_ring[rsp->tag & ~SRP_TAG_TSK_MGMT];

      if (unlikely(rsp->tag & SRP_TAG_TSK_MGMT)) {
            if (be32_to_cpu(rsp->resp_data_len) < 4)
                  req->tsk_status = -1;
            else
                  req->tsk_status = rsp->data[3];
            complete(&req->done);
      } else {
            scmnd = req->scmnd;
            if (!scmnd)
                  printk(KERN_ERR "Null scmnd for RSP w/tag %016llx\n",
                         (unsigned long long) rsp->tag);
            scmnd->result = rsp->status;

            if (rsp->flags & SRP_RSP_FLAG_SNSVALID) {
                  memcpy(scmnd->sense_buffer, rsp->data +
                         be32_to_cpu(rsp->resp_data_len),
                         min_t(int, be32_to_cpu(rsp->sense_data_len),
                             SCSI_SENSE_BUFFERSIZE));
            }

            if (rsp->flags & (SRP_RSP_FLAG_DOOVER | SRP_RSP_FLAG_DOUNDER))
                  scsi_set_resid(scmnd, be32_to_cpu(rsp->data_out_res_cnt));
            else if (rsp->flags & (SRP_RSP_FLAG_DIOVER | SRP_RSP_FLAG_DIUNDER))
                  scsi_set_resid(scmnd, be32_to_cpu(rsp->data_in_res_cnt));

            if (!req->tsk_mgmt) {
                  scmnd->host_scribble = (void *) -1L;
                  scmnd->scsi_done(scmnd);

                  srp_remove_req(target, req);
            } else
                  req->cmd_done = 1;
      }

      spin_unlock_irqrestore(target->scsi_host->host_lock, flags);
}

static void srp_handle_recv(struct srp_target_port *target, struct ib_wc *wc)
{
      struct ib_device *dev;
      struct srp_iu *iu;
      u8 opcode;

      iu = target->rx_ring[wc->wr_id & ~SRP_OP_RECV];

      dev = target->srp_host->dev->dev;
      ib_dma_sync_single_for_cpu(dev, iu->dma, target->max_ti_iu_len,
                           DMA_FROM_DEVICE);

      opcode = *(u8 *) iu->buf;

      if (0) {
            int i;

            printk(KERN_ERR PFX "recv completion, opcode 0x%02x\n", opcode);

            for (i = 0; i < wc->byte_len; ++i) {
                  if (i % 8 == 0)
                        printk(KERN_ERR "  [%02x] ", i);
                  printk(" %02x", ((u8 *) iu->buf)[i]);
                  if ((i + 1) % 8 == 0)
                        printk("\n");
            }

            if (wc->byte_len % 8)
                  printk("\n");
      }

      switch (opcode) {
      case SRP_RSP:
            srp_process_rsp(target, iu->buf);
            break;

      case SRP_T_LOGOUT:
            /* XXX Handle target logout */
            printk(KERN_WARNING PFX "Got target logout request\n");
            break;

      default:
            printk(KERN_WARNING PFX "Unhandled SRP opcode 0x%02x\n", opcode);
            break;
      }

      ib_dma_sync_single_for_device(dev, iu->dma, target->max_ti_iu_len,
                              DMA_FROM_DEVICE);
}

static void srp_completion(struct ib_cq *cq, void *target_ptr)
{
      struct srp_target_port *target = target_ptr;
      struct ib_wc wc;

      ib_req_notify_cq(cq, IB_CQ_NEXT_COMP);
      while (ib_poll_cq(cq, 1, &wc) > 0) {
            if (wc.status) {
                  printk(KERN_ERR PFX "failed %s status %d\n",
                         wc.wr_id & SRP_OP_RECV ? "receive" : "send",
                         wc.status);
                  target->qp_in_error = 1;
                  break;
            }

            if (wc.wr_id & SRP_OP_RECV)
                  srp_handle_recv(target, &wc);
            else
                  ++target->tx_tail;
      }
}

static int __srp_post_recv(struct srp_target_port *target)
{
      struct srp_iu *iu;
      struct ib_sge list;
      struct ib_recv_wr wr, *bad_wr;
      unsigned int next;
      int ret;

      next   = target->rx_head & (SRP_RQ_SIZE - 1);
      wr.wr_id = next | SRP_OP_RECV;
      iu     = target->rx_ring[next];

      list.addr   = iu->dma;
      list.length = iu->size;
      list.lkey   = target->srp_host->dev->mr->lkey;

      wr.next     = NULL;
      wr.sg_list  = &list;
      wr.num_sge  = 1;

      ret = ib_post_recv(target->qp, &wr, &bad_wr);
      if (!ret)
            ++target->rx_head;

      return ret;
}

static int srp_post_recv(struct srp_target_port *target)
{
      unsigned long flags;
      int ret;

      spin_lock_irqsave(target->scsi_host->host_lock, flags);
      ret = __srp_post_recv(target);
      spin_unlock_irqrestore(target->scsi_host->host_lock, flags);

      return ret;
}

/*
 * Must be called with target->scsi_host->host_lock held to protect
 * req_lim and tx_head.  Lock cannot be dropped between call here and
 * call to __srp_post_send().
 */
static struct srp_iu *__srp_get_tx_iu(struct srp_target_port *target)
{
      if (target->tx_head - target->tx_tail >= SRP_SQ_SIZE)
            return NULL;

      if (unlikely(target->req_lim < 1))
            ++target->zero_req_lim;

      return target->tx_ring[target->tx_head & SRP_SQ_SIZE];
}

/*
 * Must be called with target->scsi_host->host_lock held to protect
 * req_lim and tx_head.
 */
static int __srp_post_send(struct srp_target_port *target,
                     struct srp_iu *iu, int len)
{
      struct ib_sge list;
      struct ib_send_wr wr, *bad_wr;
      int ret = 0;

      list.addr   = iu->dma;
      list.length = len;
      list.lkey   = target->srp_host->dev->mr->lkey;

      wr.next       = NULL;
      wr.wr_id      = target->tx_head & SRP_SQ_SIZE;
      wr.sg_list    = &list;
      wr.num_sge    = 1;
      wr.opcode     = IB_WR_SEND;
      wr.send_flags = IB_SEND_SIGNALED;

      ret = ib_post_send(target->qp, &wr, &bad_wr);

      if (!ret) {
            ++target->tx_head;
            --target->req_lim;
      }

      return ret;
}

static int srp_queuecommand(struct scsi_cmnd *scmnd,
                      void (*done)(struct scsi_cmnd *))
{
      struct srp_target_port *target = host_to_target(scmnd->device->host);
      struct srp_request *req;
      struct srp_iu *iu;
      struct srp_cmd *cmd;
      struct ib_device *dev;
      int len;

      if (target->state == SRP_TARGET_CONNECTING)
            goto err;

      if (target->state == SRP_TARGET_DEAD ||
          target->state == SRP_TARGET_REMOVED) {
            scmnd->result = DID_BAD_TARGET << 16;
            done(scmnd);
            return 0;
      }

      iu = __srp_get_tx_iu(target);
      if (!iu)
            goto err;

      dev = target->srp_host->dev->dev;
      ib_dma_sync_single_for_cpu(dev, iu->dma, srp_max_iu_len,
                           DMA_TO_DEVICE);

      req = list_entry(target->free_reqs.next, struct srp_request, list);

      scmnd->scsi_done     = done;
      scmnd->result        = 0;
      scmnd->host_scribble = (void *) (long) req->index;

      cmd = iu->buf;
      memset(cmd, 0, sizeof *cmd);

      cmd->opcode = SRP_CMD;
      cmd->lun    = cpu_to_be64((u64) scmnd->device->lun << 48);
      cmd->tag    = req->index;
      memcpy(cmd->cdb, scmnd->cmnd, scmnd->cmd_len);

      req->scmnd    = scmnd;
      req->cmd      = iu;
      req->cmd_done = 0;
      req->tsk_mgmt = NULL;

      len = srp_map_data(scmnd, target, req);
      if (len < 0) {
            printk(KERN_ERR PFX "Failed to map data\n");
            goto err;
      }

      if (__srp_post_recv(target)) {
            printk(KERN_ERR PFX "Recv failed\n");
            goto err_unmap;
      }

      ib_dma_sync_single_for_device(dev, iu->dma, srp_max_iu_len,
                              DMA_TO_DEVICE);

      if (__srp_post_send(target, iu, len)) {
            printk(KERN_ERR PFX "Send failed\n");
            goto err_unmap;
      }

      list_move_tail(&req->list, &target->req_queue);

      return 0;

err_unmap:
      srp_unmap_data(scmnd, target, req);

err:
      return SCSI_MLQUEUE_HOST_BUSY;
}

static int srp_alloc_iu_bufs(struct srp_target_port *target)
{
      int i;

      for (i = 0; i < SRP_RQ_SIZE; ++i) {
            target->rx_ring[i] = srp_alloc_iu(target->srp_host,
                                      target->max_ti_iu_len,
                                      GFP_KERNEL, DMA_FROM_DEVICE);
            if (!target->rx_ring[i])
                  goto err;
      }

      for (i = 0; i < SRP_SQ_SIZE + 1; ++i) {
            target->tx_ring[i] = srp_alloc_iu(target->srp_host,
                                      srp_max_iu_len,
                                      GFP_KERNEL, DMA_TO_DEVICE);
            if (!target->tx_ring[i])
                  goto err;
      }

      return 0;

err:
      for (i = 0; i < SRP_RQ_SIZE; ++i) {
            srp_free_iu(target->srp_host, target->rx_ring[i]);
            target->rx_ring[i] = NULL;
      }

      for (i = 0; i < SRP_SQ_SIZE + 1; ++i) {
            srp_free_iu(target->srp_host, target->tx_ring[i]);
            target->tx_ring[i] = NULL;
      }

      return -ENOMEM;
}

static void srp_cm_rej_handler(struct ib_cm_id *cm_id,
                         struct ib_cm_event *event,
                         struct srp_target_port *target)
{
      struct ib_class_port_info *cpi;
      int opcode;

      switch (event->param.rej_rcvd.reason) {
      case IB_CM_REJ_PORT_CM_REDIRECT:
            cpi = event->param.rej_rcvd.ari;
            target->path.dlid = cpi->redirect_lid;
            target->path.pkey = cpi->redirect_pkey;
            cm_id->remote_cm_qpn = be32_to_cpu(cpi->redirect_qp) & 0x00ffffff;
            memcpy(target->path.dgid.raw, cpi->redirect_gid, 16);

            target->status = target->path.dlid ?
                  SRP_DLID_REDIRECT : SRP_PORT_REDIRECT;
            break;

      case IB_CM_REJ_PORT_REDIRECT:
            if (srp_target_is_topspin(target)) {
                  /*
                   * Topspin/Cisco SRP gateways incorrectly send
                   * reject reason code 25 when they mean 24
                   * (port redirect).
                   */
                  memcpy(target->path.dgid.raw,
                         event->param.rej_rcvd.ari, 16);

                  printk(KERN_DEBUG PFX "Topspin/Cisco redirect to target port GID %016llx%016llx\n",
                         (unsigned long long) be64_to_cpu(target->path.dgid.global.subnet_prefix),
                         (unsigned long long) be64_to_cpu(target->path.dgid.global.interface_id));

                  target->status = SRP_PORT_REDIRECT;
            } else {
                  printk(KERN_WARNING "  REJ reason: IB_CM_REJ_PORT_REDIRECT\n");
                  target->status = -ECONNRESET;
            }
            break;

      case IB_CM_REJ_DUPLICATE_LOCAL_COMM_ID:
            printk(KERN_WARNING "  REJ reason: IB_CM_REJ_DUPLICATE_LOCAL_COMM_ID\n");
            target->status = -ECONNRESET;
            break;

      case IB_CM_REJ_CONSUMER_DEFINED:
            opcode = *(u8 *) event->private_data;
            if (opcode == SRP_LOGIN_REJ) {
                  struct srp_login_rej *rej = event->private_data;
                  u32 reason = be32_to_cpu(rej->reason);

                  if (reason == SRP_LOGIN_REJ_REQ_IT_IU_LENGTH_TOO_LARGE)
                        printk(KERN_WARNING PFX
                               "SRP_LOGIN_REJ: requested max_it_iu_len too large\n");
                  else
                        printk(KERN_WARNING PFX
                               "SRP LOGIN REJECTED, reason 0x%08x\n", reason);
            } else
                  printk(KERN_WARNING "  REJ reason: IB_CM_REJ_CONSUMER_DEFINED,"
                         " opcode 0x%02x\n", opcode);
            target->status = -ECONNRESET;
            break;

      default:
            printk(KERN_WARNING "  REJ reason 0x%x\n",
                   event->param.rej_rcvd.reason);
            target->status = -ECONNRESET;
      }
}

static int srp_cm_handler(struct ib_cm_id *cm_id, struct ib_cm_event *event)
{
      struct srp_target_port *target = cm_id->context;
      struct ib_qp_attr *qp_attr = NULL;
      int attr_mask = 0;
      int comp = 0;
      int opcode = 0;

      switch (event->event) {
      case IB_CM_REQ_ERROR:
            printk(KERN_DEBUG PFX "Sending CM REQ failed\n");
            comp = 1;
            target->status = -ECONNRESET;
            break;

      case IB_CM_REP_RECEIVED:
            comp = 1;
            opcode = *(u8 *) event->private_data;

            if (opcode == SRP_LOGIN_RSP) {
                  struct srp_login_rsp *rsp = event->private_data;

                  target->max_ti_iu_len = be32_to_cpu(rsp->max_ti_iu_len);
                  target->req_lim       = be32_to_cpu(rsp->req_lim_delta);

                  target->scsi_host->can_queue = min(target->req_lim,
                                             target->scsi_host->can_queue);
            } else {
                  printk(KERN_WARNING PFX "Unhandled RSP opcode %#x\n", opcode);
                  target->status = -ECONNRESET;
                  break;
            }

            if (!target->rx_ring[0]) {
                  target->status = srp_alloc_iu_bufs(target);
                  if (target->status)
                        break;
            }

            qp_attr = kmalloc(sizeof *qp_attr, GFP_KERNEL);
            if (!qp_attr) {
                  target->status = -ENOMEM;
                  break;
            }

            qp_attr->qp_state = IB_QPS_RTR;
            target->status = ib_cm_init_qp_attr(cm_id, qp_attr, &attr_mask);
            if (target->status)
                  break;

            target->status = ib_modify_qp(target->qp, qp_attr, attr_mask);
            if (target->status)
                  break;

            target->status = srp_post_recv(target);
            if (target->status)
                  break;

            qp_attr->qp_state = IB_QPS_RTS;
            target->status = ib_cm_init_qp_attr(cm_id, qp_attr, &attr_mask);
            if (target->status)
                  break;

            target->status = ib_modify_qp(target->qp, qp_attr, attr_mask);
            if (target->status)
                  break;

            target->status = ib_send_cm_rtu(cm_id, NULL, 0);
            if (target->status)
                  break;

            break;

      case IB_CM_REJ_RECEIVED:
            printk(KERN_DEBUG PFX "REJ received\n");
            comp = 1;

            srp_cm_rej_handler(cm_id, event, target);
            break;

      case IB_CM_DREQ_RECEIVED:
            printk(KERN_WARNING PFX "DREQ received - connection closed\n");
            if (ib_send_cm_drep(cm_id, NULL, 0))
                  printk(KERN_ERR PFX "Sending CM DREP failed\n");
            break;

      case IB_CM_TIMEWAIT_EXIT:
            printk(KERN_ERR PFX "connection closed\n");

            comp = 1;
            target->status = 0;
            break;

      case IB_CM_MRA_RECEIVED:
      case IB_CM_DREQ_ERROR:
      case IB_CM_DREP_RECEIVED:
            break;

      default:
            printk(KERN_WARNING PFX "Unhandled CM event %d\n", event->event);
            break;
      }

      if (comp)
            complete(&target->done);

      kfree(qp_attr);

      return 0;
}

static int srp_send_tsk_mgmt(struct srp_target_port *target,
                       struct srp_request *req, u8 func)
{
      struct srp_iu *iu;
      struct srp_tsk_mgmt *tsk_mgmt;

      spin_lock_irq(target->scsi_host->host_lock);

      if (target->state == SRP_TARGET_DEAD ||
          target->state == SRP_TARGET_REMOVED) {
            req->scmnd->result = DID_BAD_TARGET << 16;
            goto out;
      }

      init_completion(&req->done);

      iu = __srp_get_tx_iu(target);
      if (!iu)
            goto out;

      tsk_mgmt = iu->buf;
      memset(tsk_mgmt, 0, sizeof *tsk_mgmt);

      tsk_mgmt->opcode  = SRP_TSK_MGMT;
      tsk_mgmt->lun           = cpu_to_be64((u64) req->scmnd->device->lun << 48);
      tsk_mgmt->tag           = req->index | SRP_TAG_TSK_MGMT;
      tsk_mgmt->tsk_mgmt_func = func;
      tsk_mgmt->task_tag      = req->index;

      if (__srp_post_send(target, iu, sizeof *tsk_mgmt))
            goto out;

      req->tsk_mgmt = iu;

      spin_unlock_irq(target->scsi_host->host_lock);

      if (!wait_for_completion_timeout(&req->done,
                               msecs_to_jiffies(SRP_ABORT_TIMEOUT_MS)))
            return -1;

      return 0;

out:
      spin_unlock_irq(target->scsi_host->host_lock);
      return -1;
}

static int srp_find_req(struct srp_target_port *target,
                  struct scsi_cmnd *scmnd,
                  struct srp_request **req)
{
      if (scmnd->host_scribble == (void *) -1L)
            return -1;

      *req = &target->req_ring[(long) scmnd->host_scribble];

      return 0;
}

static int srp_abort(struct scsi_cmnd *scmnd)
{
      struct srp_target_port *target = host_to_target(scmnd->device->host);
      struct srp_request *req;
      int ret = SUCCESS;

      printk(KERN_ERR "SRP abort called\n");

      if (target->qp_in_error)
            return FAILED;
      if (srp_find_req(target, scmnd, &req))
            return FAILED;
      if (srp_send_tsk_mgmt(target, req, SRP_TSK_ABORT_TASK))
            return FAILED;

      spin_lock_irq(target->scsi_host->host_lock);

      if (req->cmd_done) {
            srp_remove_req(target, req);
            scmnd->scsi_done(scmnd);
      } else if (!req->tsk_status) {
            srp_remove_req(target, req);
            scmnd->result = DID_ABORT << 16;
      } else
            ret = FAILED;

      spin_unlock_irq(target->scsi_host->host_lock);

      return ret;
}

static int srp_reset_device(struct scsi_cmnd *scmnd)
{
      struct srp_target_port *target = host_to_target(scmnd->device->host);
      struct srp_request *req, *tmp;

      printk(KERN_ERR "SRP reset_device called\n");

      if (target->qp_in_error)
            return FAILED;
      if (srp_find_req(target, scmnd, &req))
            return FAILED;
      if (srp_send_tsk_mgmt(target, req, SRP_TSK_LUN_RESET))
            return FAILED;
      if (req->tsk_status)
            return FAILED;

      spin_lock_irq(target->scsi_host->host_lock);

      list_for_each_entry_safe(req, tmp, &target->req_queue, list)
            if (req->scmnd->device == scmnd->device)
                  srp_reset_req(target, req);

      spin_unlock_irq(target->scsi_host->host_lock);

      return SUCCESS;
}

static int srp_reset_host(struct scsi_cmnd *scmnd)
{
      struct srp_target_port *target = host_to_target(scmnd->device->host);
      int ret = FAILED;

      printk(KERN_ERR PFX "SRP reset_host called\n");

      if (!srp_reconnect_target(target))
            ret = SUCCESS;

      return ret;
}

static ssize_t show_id_ext(struct class_device *cdev, char *buf)
{
      struct srp_target_port *target = host_to_target(class_to_shost(cdev));

      if (target->state == SRP_TARGET_DEAD ||
          target->state == SRP_TARGET_REMOVED)
            return -ENODEV;

      return sprintf(buf, "0x%016llx\n",
                   (unsigned long long) be64_to_cpu(target->id_ext));
}

static ssize_t show_ioc_guid(struct class_device *cdev, char *buf)
{
      struct srp_target_port *target = host_to_target(class_to_shost(cdev));

      if (target->state == SRP_TARGET_DEAD ||
          target->state == SRP_TARGET_REMOVED)
            return -ENODEV;

      return sprintf(buf, "0x%016llx\n",
                   (unsigned long long) be64_to_cpu(target->ioc_guid));
}

static ssize_t show_service_id(struct class_device *cdev, char *buf)
{
      struct srp_target_port *target = host_to_target(class_to_shost(cdev));

      if (target->state == SRP_TARGET_DEAD ||
          target->state == SRP_TARGET_REMOVED)
            return -ENODEV;

      return sprintf(buf, "0x%016llx\n",
                   (unsigned long long) be64_to_cpu(target->service_id));
}

static ssize_t show_pkey(struct class_device *cdev, char *buf)
{
      struct srp_target_port *target = host_to_target(class_to_shost(cdev));

      if (target->state == SRP_TARGET_DEAD ||
          target->state == SRP_TARGET_REMOVED)
            return -ENODEV;

      return sprintf(buf, "0x%04x\n", be16_to_cpu(target->path.pkey));
}

static ssize_t show_dgid(struct class_device *cdev, char *buf)
{
      struct srp_target_port *target = host_to_target(class_to_shost(cdev));

      if (target->state == SRP_TARGET_DEAD ||
          target->state == SRP_TARGET_REMOVED)
            return -ENODEV;

      return sprintf(buf, "%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x\n",
                   be16_to_cpu(((__be16 *) target->path.dgid.raw)[0]),
                   be16_to_cpu(((__be16 *) target->path.dgid.raw)[1]),
                   be16_to_cpu(((__be16 *) target->path.dgid.raw)[2]),
                   be16_to_cpu(((__be16 *) target->path.dgid.raw)[3]),
                   be16_to_cpu(((__be16 *) target->path.dgid.raw)[4]),
                   be16_to_cpu(((__be16 *) target->path.dgid.raw)[5]),
                   be16_to_cpu(((__be16 *) target->path.dgid.raw)[6]),
                   be16_to_cpu(((__be16 *) target->path.dgid.raw)[7]));
}

static ssize_t show_orig_dgid(struct class_device *cdev, char *buf)
{
      struct srp_target_port *target = host_to_target(class_to_shost(cdev));

      if (target->state == SRP_TARGET_DEAD ||
          target->state == SRP_TARGET_REMOVED)
            return -ENODEV;

      return sprintf(buf, "%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x\n",
                   be16_to_cpu(target->orig_dgid[0]),
                   be16_to_cpu(target->orig_dgid[1]),
                   be16_to_cpu(target->orig_dgid[2]),
                   be16_to_cpu(target->orig_dgid[3]),
                   be16_to_cpu(target->orig_dgid[4]),
                   be16_to_cpu(target->orig_dgid[5]),
                   be16_to_cpu(target->orig_dgid[6]),
                   be16_to_cpu(target->orig_dgid[7]));
}

static ssize_t show_zero_req_lim(struct class_device *cdev, char *buf)
{
      struct srp_target_port *target = host_to_target(class_to_shost(cdev));

      if (target->state == SRP_TARGET_DEAD ||
          target->state == SRP_TARGET_REMOVED)
            return -ENODEV;

      return sprintf(buf, "%d\n", target->zero_req_lim);
}

static ssize_t show_local_ib_port(struct class_device *cdev, char *buf)
{
      struct srp_target_port *target = host_to_target(class_to_shost(cdev));

      return sprintf(buf, "%d\n", target->srp_host->port);
}

static ssize_t show_local_ib_device(struct class_device *cdev, char *buf)
{
      struct srp_target_port *target = host_to_target(class_to_shost(cdev));

      return sprintf(buf, "%s\n", target->srp_host->dev->dev->name);
}

static CLASS_DEVICE_ATTR(id_ext,      S_IRUGO, show_id_ext,        NULL);
static CLASS_DEVICE_ATTR(ioc_guid,    S_IRUGO, show_ioc_guid,      NULL);
static CLASS_DEVICE_ATTR(service_id,        S_IRUGO, show_service_id,    NULL);
static CLASS_DEVICE_ATTR(pkey,              S_IRUGO, show_pkey,          NULL);
static CLASS_DEVICE_ATTR(dgid,              S_IRUGO, show_dgid,          NULL);
static CLASS_DEVICE_ATTR(orig_dgid,   S_IRUGO, show_orig_dgid,     NULL);
static CLASS_DEVICE_ATTR(zero_req_lim,      S_IRUGO, show_zero_req_lim,  NULL);
static CLASS_DEVICE_ATTR(local_ib_port,   S_IRUGO, show_local_ib_port,   NULL);
static CLASS_DEVICE_ATTR(local_ib_device, S_IRUGO, show_local_ib_device, NULL);

static struct class_device_attribute *srp_host_attrs[] = {
      &class_device_attr_id_ext,
      &class_device_attr_ioc_guid,
      &class_device_attr_service_id,
      &class_device_attr_pkey,
      &class_device_attr_dgid,
      &class_device_attr_orig_dgid,
      &class_device_attr_zero_req_lim,
      &class_device_attr_local_ib_port,
      &class_device_attr_local_ib_device,
      NULL
};

static struct scsi_host_template srp_template = {
      .module                       = THIS_MODULE,
      .name                   = "InfiniBand SRP initiator",
      .proc_name              = DRV_NAME,
      .info                   = srp_target_info,
      .queuecommand                 = srp_queuecommand,
      .eh_abort_handler       = srp_abort,
      .eh_device_reset_handler      = srp_reset_device,
      .eh_host_reset_handler        = srp_reset_host,
      .can_queue              = SRP_SQ_SIZE,
      .this_id                = -1,
      .cmd_per_lun                  = SRP_SQ_SIZE,
      .use_clustering               = ENABLE_CLUSTERING,
      .shost_attrs                  = srp_host_attrs
};

static int srp_add_target(struct srp_host *host, struct srp_target_port *target)
{
      struct srp_rport_identifiers ids;
      struct srp_rport *rport;

      sprintf(target->target_name, "SRP.T10:%016llX",
             (unsigned long long) be64_to_cpu(target->id_ext));

      if (scsi_add_host(target->scsi_host, host->dev->dev->dma_device))
            return -ENODEV;

      memcpy(ids.port_id, &target->id_ext, 8);
      memcpy(ids.port_id + 8, &target->ioc_guid, 8);
      ids.roles = SRP_RPORT_ROLE_TARGET;
      rport = srp_rport_add(target->scsi_host, &ids);
      if (IS_ERR(rport)) {
            scsi_remove_host(target->scsi_host);
            return PTR_ERR(rport);
      }

      spin_lock(&host->target_lock);
      list_add_tail(&target->list, &host->target_list);
      spin_unlock(&host->target_lock);

      target->state = SRP_TARGET_LIVE;

      scsi_scan_target(&target->scsi_host->shost_gendev,
                   0, target->scsi_id, SCAN_WILD_CARD, 0);

      return 0;
}

static void srp_release_class_dev(struct class_device *class_dev)
{
      struct srp_host *host =
            container_of(class_dev, struct srp_host, class_dev);

      complete(&host->released);
}

static struct class srp_class = {
      .name    = "infiniband_srp",
      .release = srp_release_class_dev
};

/*
 * Target ports are added by writing
 *
 *     id_ext=<SRP ID ext>,ioc_guid=<SRP IOC GUID>,dgid=<dest GID>,
 *     pkey=<P_Key>,service_id=<service ID>
 *
 * to the add_target sysfs attribute.
 */
enum {
      SRP_OPT_ERR       = 0,
      SRP_OPT_ID_EXT          = 1 << 0,
      SRP_OPT_IOC_GUID  = 1 << 1,
      SRP_OPT_DGID            = 1 << 2,
      SRP_OPT_PKEY            = 1 << 3,
      SRP_OPT_SERVICE_ID      = 1 << 4,
      SRP_OPT_MAX_SECT  = 1 << 5,
      SRP_OPT_MAX_CMD_PER_LUN = 1 << 6,
      SRP_OPT_IO_CLASS  = 1 << 7,
      SRP_OPT_INITIATOR_EXT   = 1 << 8,
      SRP_OPT_ALL       = (SRP_OPT_ID_EXT |
                           SRP_OPT_IOC_GUID     |
                           SRP_OPT_DGID         |
                           SRP_OPT_PKEY         |
                           SRP_OPT_SERVICE_ID),
};

static match_table_t srp_opt_tokens = {
      { SRP_OPT_ID_EXT,       "id_ext=%s"             },
      { SRP_OPT_IOC_GUID,           "ioc_guid=%s"           },
      { SRP_OPT_DGID,               "dgid=%s"         },
      { SRP_OPT_PKEY,               "pkey=%x"         },
      { SRP_OPT_SERVICE_ID,         "service_id=%s"         },
      { SRP_OPT_MAX_SECT,           "max_sect=%d"           },
      { SRP_OPT_MAX_CMD_PER_LUN,    "max_cmd_per_lun=%d"    },
      { SRP_OPT_IO_CLASS,           "io_class=%x"           },
      { SRP_OPT_INITIATOR_EXT,      "initiator_ext=%s"      },
      { SRP_OPT_ERR,                NULL              }
};

static int srp_parse_options(const char *buf, struct srp_target_port *target)
{
      char *options, *sep_opt;
      char *p;
      char dgid[3];
      substring_t args[MAX_OPT_ARGS];
      int opt_mask = 0;
      int token;
      int ret = -EINVAL;
      int i;

      options = kstrdup(buf, GFP_KERNEL);
      if (!options)
            return -ENOMEM;

      sep_opt = options;
      while ((p = strsep(&sep_opt, ",")) != NULL) {
            if (!*p)
                  continue;

            token = match_token(p, srp_opt_tokens, args);
            opt_mask |= token;

            switch (token) {
            case SRP_OPT_ID_EXT:
                  p = match_strdup(args);
                  if (!p) {
                        ret = -ENOMEM;
                        goto out;
                  }
                  target->id_ext = cpu_to_be64(simple_strtoull(p, NULL, 16));
                  kfree(p);
                  break;

            case SRP_OPT_IOC_GUID:
                  p = match_strdup(args);
                  if (!p) {
                        ret = -ENOMEM;
                        goto out;
                  }
                  target->ioc_guid = cpu_to_be64(simple_strtoull(p, NULL, 16));
                  kfree(p);
                  break;

            case SRP_OPT_DGID:
                  p = match_strdup(args);
                  if (!p) {
                        ret = -ENOMEM;
                        goto out;
                  }
                  if (strlen(p) != 32) {
                        printk(KERN_WARNING PFX "bad dest GID parameter '%s'\n", p);
                        kfree(p);
                        goto out;
                  }

                  for (i = 0; i < 16; ++i) {
                        strlcpy(dgid, p + i * 2, 3);
                        target->path.dgid.raw[i] = simple_strtoul(dgid, NULL, 16);
                  }
                  kfree(p);
                  memcpy(target->orig_dgid, target->path.dgid.raw, 16);
                  break;

            case SRP_OPT_PKEY:
                  if (match_hex(args, &token)) {
                        printk(KERN_WARNING PFX "bad P_Key parameter '%s'\n", p);
                        goto out;
                  }
                  target->path.pkey = cpu_to_be16(token);
                  break;

            case SRP_OPT_SERVICE_ID:
                  p = match_strdup(args);
                  if (!p) {
                        ret = -ENOMEM;
                        goto out;
                  }
                  target->service_id = cpu_to_be64(simple_strtoull(p, NULL, 16));
                  target->path.service_id = target->service_id;
                  kfree(p);
                  break;

            case SRP_OPT_MAX_SECT:
                  if (match_int(args, &token)) {
                        printk(KERN_WARNING PFX "bad max sect parameter '%s'\n", p);
                        goto out;
                  }
                  target->scsi_host->max_sectors = token;
                  break;

            case SRP_OPT_MAX_CMD_PER_LUN:
                  if (match_int(args, &token)) {
                        printk(KERN_WARNING PFX "bad max cmd_per_lun parameter '%s'\n", p);
                        goto out;
                  }
                  target->scsi_host->cmd_per_lun = min(token, SRP_SQ_SIZE);
                  break;

            case SRP_OPT_IO_CLASS:
                  if (match_hex(args, &token)) {
                        printk(KERN_WARNING PFX "bad  IO class parameter '%s' \n", p);
                        goto out;
                  }
                  if (token != SRP_REV10_IB_IO_CLASS &&
                      token != SRP_REV16A_IB_IO_CLASS) {
                        printk(KERN_WARNING PFX "unknown IO class parameter value"
                               " %x specified (use %x or %x).\n",
                               token, SRP_REV10_IB_IO_CLASS, SRP_REV16A_IB_IO_CLASS);
                        goto out;
                  }
                  target->io_class = token;
                  break;

            case SRP_OPT_INITIATOR_EXT:
                  p = match_strdup(args);
                  if (!p) {
                        ret = -ENOMEM;
                        goto out;
                  }
                  target->initiator_ext = cpu_to_be64(simple_strtoull(p, NULL, 16));
                  kfree(p);
                  break;

            default:
                  printk(KERN_WARNING PFX "unknown parameter or missing value "
                         "'%s' in target creation request\n", p);
                  goto out;
            }
      }

      if ((opt_mask & SRP_OPT_ALL) == SRP_OPT_ALL)
            ret = 0;
      else
            for (i = 0; i < ARRAY_SIZE(srp_opt_tokens); ++i)
                  if ((srp_opt_tokens[i].token & SRP_OPT_ALL) &&
                      !(srp_opt_tokens[i].token & opt_mask))
                        printk(KERN_WARNING PFX "target creation request is "
                               "missing parameter '%s'\n",
                               srp_opt_tokens[i].pattern);

out:
      kfree(options);
      return ret;
}

static ssize_t srp_create_target(struct class_device *class_dev,
                         const char *buf, size_t count)
{
      struct srp_host *host =
            container_of(class_dev, struct srp_host, class_dev);
      struct Scsi_Host *target_host;
      struct srp_target_port *target;
      int ret;
      int i;

      target_host = scsi_host_alloc(&srp_template,
                              sizeof (struct srp_target_port));
      if (!target_host)
            return -ENOMEM;

      target_host->transportt = ib_srp_transport_template;
      target_host->max_lun     = SRP_MAX_LUN;
      target_host->max_cmd_len = sizeof ((struct srp_cmd *) (void *) 0L)->cdb;

      target = host_to_target(target_host);

      target->io_class   = SRP_REV16A_IB_IO_CLASS;
      target->scsi_host  = target_host;
      target->srp_host   = host;

      INIT_LIST_HEAD(&target->free_reqs);
      INIT_LIST_HEAD(&target->req_queue);
      for (i = 0; i < SRP_SQ_SIZE; ++i) {
            target->req_ring[i].index = i;
            list_add_tail(&target->req_ring[i].list, &target->free_reqs);
      }

      ret = srp_parse_options(buf, target);
      if (ret)
            goto err;

      ib_get_cached_gid(host->dev->dev, host->port, 0, &target->path.sgid);

      printk(KERN_DEBUG PFX "new target: id_ext %016llx ioc_guid %016llx pkey %04x "
             "service_id %016llx dgid %04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x\n",
             (unsigned long long) be64_to_cpu(target->id_ext),
             (unsigned long long) be64_to_cpu(target->ioc_guid),
             be16_to_cpu(target->path.pkey),
             (unsigned long long) be64_to_cpu(target->service_id),
             (int) be16_to_cpu(*(__be16 *) &target->path.dgid.raw[0]),
             (int) be16_to_cpu(*(__be16 *) &target->path.dgid.raw[2]),
             (int) be16_to_cpu(*(__be16 *) &target->path.dgid.raw[4]),
             (int) be16_to_cpu(*(__be16 *) &target->path.dgid.raw[6]),
             (int) be16_to_cpu(*(__be16 *) &target->path.dgid.raw[8]),
             (int) be16_to_cpu(*(__be16 *) &target->path.dgid.raw[10]),
             (int) be16_to_cpu(*(__be16 *) &target->path.dgid.raw[12]),
             (int) be16_to_cpu(*(__be16 *) &target->path.dgid.raw[14]));

      ret = srp_create_target_ib(target);
      if (ret)
            goto err;

      target->cm_id = ib_create_cm_id(host->dev->dev, srp_cm_handler, target);
      if (IS_ERR(target->cm_id)) {
            ret = PTR_ERR(target->cm_id);
            goto err_free;
      }

      target->qp_in_error = 0;
      ret = srp_connect_target(target);
      if (ret) {
            printk(KERN_ERR PFX "Connection failed\n");
            goto err_cm_id;
      }

      ret = srp_add_target(host, target);
      if (ret)
            goto err_disconnect;

      return count;

err_disconnect:
      srp_disconnect_target(target);

err_cm_id:
      ib_destroy_cm_id(target->cm_id);

err_free:
      srp_free_target_ib(target);

err:
      scsi_host_put(target_host);

      return ret;
}

static CLASS_DEVICE_ATTR(add_target, S_IWUSR, NULL, srp_create_target);

static ssize_t show_ibdev(struct class_device *class_dev, char *buf)
{
      struct srp_host *host =
            container_of(class_dev, struct srp_host, class_dev);

      return sprintf(buf, "%s\n", host->dev->dev->name);
}

static CLASS_DEVICE_ATTR(ibdev, S_IRUGO, show_ibdev, NULL);

static ssize_t show_port(struct class_device *class_dev, char *buf)
{
      struct srp_host *host =
            container_of(class_dev, struct srp_host, class_dev);

      return sprintf(buf, "%d\n", host->port);
}

static CLASS_DEVICE_ATTR(port, S_IRUGO, show_port, NULL);

static struct srp_host *srp_add_port(struct srp_device *device, u8 port)
{
      struct srp_host *host;

      host = kzalloc(sizeof *host, GFP_KERNEL);
      if (!host)
            return NULL;

      INIT_LIST_HEAD(&host->target_list);
      spin_lock_init(&host->target_lock);
      init_completion(&host->released);
      host->dev  = device;
      host->port = port;

      host->class_dev.class = &srp_class;
      host->class_dev.dev   = device->dev->dma_device;
      snprintf(host->class_dev.class_id, BUS_ID_SIZE, "srp-%s-%d",
             device->dev->name, port);

      if (class_device_register(&host->class_dev))
            goto free_host;
      if (class_device_create_file(&host->class_dev, &class_device_attr_add_target))
            goto err_class;
      if (class_device_create_file(&host->class_dev, &class_device_attr_ibdev))
            goto err_class;
      if (class_device_create_file(&host->class_dev, &class_device_attr_port))
            goto err_class;

      return host;

err_class:
      class_device_unregister(&host->class_dev);

free_host:
      kfree(host);

      return NULL;
}

static void srp_add_one(struct ib_device *device)
{
      struct srp_device *srp_dev;
      struct ib_device_attr *dev_attr;
      struct ib_fmr_pool_param fmr_param;
      struct srp_host *host;
      int s, e, p;

      dev_attr = kmalloc(sizeof *dev_attr, GFP_KERNEL);
      if (!dev_attr)
            return;

      if (ib_query_device(device, dev_attr)) {
            printk(KERN_WARNING PFX "Query device failed for %s\n",
                   device->name);
            goto free_attr;
      }

      srp_dev = kmalloc(sizeof *srp_dev, GFP_KERNEL);
      if (!srp_dev)
            goto free_attr;

      /*
       * Use the smallest page size supported by the HCA, down to a
       * minimum of 512 bytes (which is the smallest sector that a
       * SCSI command will ever carry).
       */
      srp_dev->fmr_page_shift = max(9, ffs(dev_attr->page_size_cap) - 1);
      srp_dev->fmr_page_size  = 1 << srp_dev->fmr_page_shift;
      srp_dev->fmr_page_mask  = ~((u64) srp_dev->fmr_page_size - 1);

      INIT_LIST_HEAD(&srp_dev->dev_list);

      srp_dev->dev = device;
      srp_dev->pd  = ib_alloc_pd(device);
      if (IS_ERR(srp_dev->pd))
            goto free_dev;

      srp_dev->mr = ib_get_dma_mr(srp_dev->pd,
                            IB_ACCESS_LOCAL_WRITE |
                            IB_ACCESS_REMOTE_READ |
                            IB_ACCESS_REMOTE_WRITE);
      if (IS_ERR(srp_dev->mr))
            goto err_pd;

      memset(&fmr_param, 0, sizeof fmr_param);
      fmr_param.pool_size         = SRP_FMR_POOL_SIZE;
      fmr_param.dirty_watermark   = SRP_FMR_DIRTY_SIZE;
      fmr_param.cache             = 1;
      fmr_param.max_pages_per_fmr = SRP_FMR_SIZE;
      fmr_param.page_shift        = srp_dev->fmr_page_shift;
      fmr_param.access      = (IB_ACCESS_LOCAL_WRITE |
                               IB_ACCESS_REMOTE_WRITE |
                               IB_ACCESS_REMOTE_READ);

      srp_dev->fmr_pool = ib_create_fmr_pool(srp_dev->pd, &fmr_param);
      if (IS_ERR(srp_dev->fmr_pool))
            srp_dev->fmr_pool = NULL;

      if (device->node_type == RDMA_NODE_IB_SWITCH) {
            s = 0;
            e = 0;
      } else {
            s = 1;
            e = device->phys_port_cnt;
      }

      for (p = s; p <= e; ++p) {
            host = srp_add_port(srp_dev, p);
            if (host)
                  list_add_tail(&host->list, &srp_dev->dev_list);
      }

      ib_set_client_data(device, &srp_client, srp_dev);

      goto free_attr;

err_pd:
      ib_dealloc_pd(srp_dev->pd);

free_dev:
      kfree(srp_dev);

free_attr:
      kfree(dev_attr);
}

static void srp_remove_one(struct ib_device *device)
{
      struct srp_device *srp_dev;
      struct srp_host *host, *tmp_host;
      LIST_HEAD(target_list);
      struct srp_target_port *target, *tmp_target;

      srp_dev = ib_get_client_data(device, &srp_client);

      list_for_each_entry_safe(host, tmp_host, &srp_dev->dev_list, list) {
            class_device_unregister(&host->class_dev);
            /*
             * Wait for the sysfs entry to go away, so that no new
             * target ports can be created.
             */
            wait_for_completion(&host->released);

            /*
             * Mark all target ports as removed, so we stop queueing
             * commands and don't try to reconnect.
             */
            spin_lock(&host->target_lock);
            list_for_each_entry(target, &host->target_list, list) {
                  spin_lock_irq(target->scsi_host->host_lock);
                  target->state = SRP_TARGET_REMOVED;
                  spin_unlock_irq(target->scsi_host->host_lock);
            }
            spin_unlock(&host->target_lock);

            /*
             * Wait for any reconnection tasks that may have
             * started before we marked our target ports as
             * removed, and any target port removal tasks.
             */
            flush_scheduled_work();

            list_for_each_entry_safe(target, tmp_target,
                               &host->target_list, list) {
                  srp_remove_host(target->scsi_host);
                  scsi_remove_host(target->scsi_host);
                  srp_disconnect_target(target);
                  ib_destroy_cm_id(target->cm_id);
                  srp_free_target_ib(target);
                  scsi_host_put(target->scsi_host);
            }

            kfree(host);
      }

      if (srp_dev->fmr_pool)
            ib_destroy_fmr_pool(srp_dev->fmr_pool);
      ib_dereg_mr(srp_dev->mr);
      ib_dealloc_pd(srp_dev->pd);

      kfree(srp_dev);
}

static struct srp_function_template ib_srp_transport_functions = {
};

static int __init srp_init_module(void)
{
      int ret;

      ib_srp_transport_template =
            srp_attach_transport(&ib_srp_transport_functions);
      if (!ib_srp_transport_template)
            return -ENOMEM;

      srp_template.sg_tablesize = srp_sg_tablesize;
      srp_max_iu_len = (sizeof (struct srp_cmd) +
                    sizeof (struct srp_indirect_buf) +
                    srp_sg_tablesize * 16);

      ret = class_register(&srp_class);
      if (ret) {
            printk(KERN_ERR PFX "couldn't register class infiniband_srp\n");
            srp_release_transport(ib_srp_transport_template);
            return ret;
      }

      ib_sa_register_client(&srp_sa_client);

      ret = ib_register_client(&srp_client);
      if (ret) {
            printk(KERN_ERR PFX "couldn't register IB client\n");
            srp_release_transport(ib_srp_transport_template);
            ib_sa_unregister_client(&srp_sa_client);
            class_unregister(&srp_class);
            return ret;
      }

      return 0;
}

static void __exit srp_cleanup_module(void)
{
      ib_unregister_client(&srp_client);
      ib_sa_unregister_client(&srp_sa_client);
      class_unregister(&srp_class);
      srp_release_transport(ib_srp_transport_template);
}

module_init(srp_init_module);
module_exit(srp_cleanup_module);

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