+
+/*
+ * BSG support
+ */
+
+/**
+ * iscsi_destroy_bsgjob - routine to teardown/delete a iscsi bsg job
+ * @job:       iscsi_bsg_job that is to be torn down
+ */
+static void
+iscsi_destroy_bsgjob(struct iscsi_bsg_job *job)
+{
+       unsigned long flags;
+
+       spin_lock_irqsave(&job->job_lock, flags);
+       if (job->ref_cnt) {
+               spin_unlock_irqrestore(&job->job_lock, flags);
+               return;
+       }
+       spin_unlock_irqrestore(&job->job_lock, flags);
+
+       put_device(job->dev);        /* release reference for the request */
+
+       kfree(job->request_payload.sg_list);
+       kfree(job->reply_payload.sg_list);
+       kfree(job);
+}
+
+/**
+ * iscsi_bsg_jobdone - completion routine for bsg requests that the LLD
has
+ *                  completed
+ * @job:       iscsi_bsg_job that is complete
+ */
+static void
+iscsi_bsg_jobdone(struct iscsi_bsg_job *job)
+{
+       struct request *req = job->req;
+       struct request *rsp = req->next_rq;
+       int err;
+
+       err = job->req->errors = job->reply->result;
+
+       if (err < 0)
+               /* we're only returning the result field in the reply */
+               job->req->sense_len = sizeof(uint32_t);
+       else
+               job->req->sense_len = job->reply_len;
+
+       /* we assume all request payload was transferred, residual == 0 */
+       req->resid_len = 0;
+
+       if (rsp) {
+               WARN_ON(job->reply->reply_payload_rcv_len > rsp->resid_len);
+
+               /* set reply (bidi) residual */
+               rsp->resid_len -= min(job->reply->reply_payload_rcv_len,
+                                     rsp->resid_len);
+       }
+       blk_complete_request(req);
+}
+
+/**
+ * iscsi_bsg_softirq_done - softirq done routine for destroying the bsg
requests
+ * @rq:        BSG request that holds the job to be destroyed
+ */
+static void
+iscsi_bsg_softirq_done(struct request *rq)
+{
+       struct iscsi_bsg_job *job = rq->special;
+       unsigned long flags;
+
+       spin_lock_irqsave(&job->job_lock, flags);
+       job->state_flags |= ISCSI_RQST_STATE_DONE;
+       job->ref_cnt--;
+       spin_unlock_irqrestore(&job->job_lock, flags);
+
+       blk_end_request_all(rq, rq->errors);
+       iscsi_destroy_bsgjob(job);
+}
+
+/**
+ * iscsi_bsg_job_timeout - handler for when a bsg request timesout
+ * @req:       request that timed out
+ */
+static enum blk_eh_timer_return
+iscsi_bsg_job_timeout(struct request *req)
+{
+       struct iscsi_bsg_job *job = (void *) req->special;
+       struct Scsi_Host *shost = job->shost;
+       struct iscsi_internal *i = to_iscsi_internal(shost->transportt);
+       unsigned long flags;
+       int err = 0, done = 0;
+
+       spin_lock_irqsave(&job->job_lock, flags);
+       if (job->state_flags & ISCSI_RQST_STATE_DONE)
+               done = 1;
+       else
+               job->ref_cnt++;
+       spin_unlock_irqrestore(&job->job_lock, flags);
+
+       if (!done && i->iscsi_transport->bsg_timeout) {
+               /* call LLDD to abort the i/o as it has timed out */
+               err = i->iscsi_transport->bsg_timeout(job);
+               if (err)
+                       printk(KERN_ERR "ERROR: iSCSI BSG request timeout - "
+                               "LLD abort failed with status %d\n", err);
+       }
+
+       /* the blk_end_sync_io() doesn't check the error */
+       if (done)
+               return BLK_EH_NOT_HANDLED;
+       else
+               return BLK_EH_HANDLED;
+}
+
+static int
+iscsi_bsg_map_buffer(struct iscsi_bsg_buffer *buf, struct request *req)
+{
+       size_t sz = (sizeof(struct scatterlist) * req->nr_phys_segments);
+
+       BUG_ON(!req->nr_phys_segments);
+
+       buf->sg_list = kzalloc(sz, GFP_KERNEL);
+       if (!buf->sg_list)
+               return -ENOMEM;
+       sg_init_table(buf->sg_list, req->nr_phys_segments);
+       buf->sg_cnt = blk_rq_map_sg(req->q, req, buf->sg_list);
+       buf->payload_len = blk_rq_bytes(req);
+       return 0;
+}
+
+/**
+ * iscsi_req_to_bsgjob - Allocate/create the iscsi_bsg_job structure
for the
+ *                   bsg request
+ * @req:       BSG request that needs a job structure
+ * @shost:     SCSI Host corresponding to the bsg object
+ */
+static int
+iscsi_req_to_bsgjob(struct request *req, struct Scsi_Host *shost)
+{
+       struct iscsi_internal *i = to_iscsi_internal(shost->transportt);
+       struct request *rsp = req->next_rq;
+       struct iscsi_bsg_job *job;
+       int ret;
+
+       BUG_ON(req->special);
+
+       job = kzalloc(sizeof(struct iscsi_bsg_job) +
+                                i->iscsi_transport->dd_bsg_size, GFP_KERNEL);
+       if (!job)
+               return -ENOMEM;
+
+       /*
+        * Note: this is a bit silly.
+        * The request gets formatted as a SGIO v4 ioctl request, which
+        * then gets reformatted as a blk request, which then gets
+        * reformatted as a iscsi bsg request. And on completion, we have
+        * to wrap return results such that SGIO v4 thinks it was a scsi
+        * status.  I hope this was all worth it.
+        */
+
+       req->special = job;
+       job->shost = shost;
+       job->req = req;
+       if (i->iscsi_transport->dd_bsg_size)
+               job->dd_data = (void *)&job[1];
+       spin_lock_init(&job->job_lock);
+       job->request = (struct iscsi_bsg_request *)req->cmd;
+       job->request_len = req->cmd_len;
+       job->reply = req->sense;
+       job->reply_len = SCSI_SENSE_BUFFERSIZE;      /* Size of sense buffer
+                                                * allocated */
+       if (req->bio) {
+               ret = iscsi_bsg_map_buffer(&job->request_payload, req);
+               if (ret)
+                       goto failjob_rls_job;
+       }
+       if (rsp && rsp->bio) {
+               ret = iscsi_bsg_map_buffer(&job->reply_payload, rsp);
+               if (ret)
+                       goto failjob_rls_rqst_payload;
+       }
+       job->job_done = iscsi_bsg_jobdone;
+       job->dev = &shost->shost_gendev;
+       get_device(job->dev);                /* take a reference for the request */
+
+       job->ref_cnt = 1;
+
+       return 0;
+
+
+failjob_rls_rqst_payload:
+       kfree(job->request_payload.sg_list);
+failjob_rls_job:
+       kfree(job);
+       return -ENOMEM;
+}
+
+
+enum iscsi_dispatch_result {
+       DISPATCH_BREAK,         /* on return, q is locked, break from q loop */
+       DISPATCH_LOCKED,        /* on return, q is locked, continue on */
+       DISPATCH_UNLOCKED,      /* on return, q is unlocked, continue on */
+};
+
+/**
+ * iscsi_bsg_host_dispatch - process iscsi host bsg requests and
+ *                           dispatch to LLDD
+ * @q:         iscsi host request queue
+ * @shost:     scsi host request queue attached to
+ * @job:       bsg job to be processed
+ */
+static enum iscsi_dispatch_result
+iscsi_bsg_host_dispatch(struct request_queue *q, struct Scsi_Host
*shost,
+                        struct iscsi_bsg_job *job)
+{
+       struct iscsi_internal *i = to_iscsi_internal(shost->transportt);
+       int cmdlen = sizeof(uint32_t);  /* start with length of msgcode */
+       int ret;
+
+       /* Validate the host command */
+       switch (job->request->msgcode) {
+       case ISCSI_BSG_HST_VENDOR:
+               cmdlen += sizeof(struct iscsi_bsg_host_vendor);
+               if ((shost->hostt->vendor_id == 0L) ||
+                   (job->request->rqst_data.h_vendor.vendor_id !=
+                       shost->hostt->vendor_id)) {
+                       ret = -ESRCH;
+                       goto fail_host_msg;
+               }
+               break;
+
+       default:
+               ret = -EBADR;
+               goto fail_host_msg;
+       }
+
+       /* check if we really have all the request data needed */
+       if (job->request_len < cmdlen) {
+               ret = -ENOMSG;
+               goto fail_host_msg;
+       }
+
+       ret = i->iscsi_transport->bsg_request(job);
+       if (!ret)
+               return DISPATCH_UNLOCKED;
+
+fail_host_msg:
+       /* return the errno failure code as the only status */
+       BUG_ON(job->reply_len < sizeof(uint32_t));
+       job->reply->result = ret;
+       job->reply_len = sizeof(uint32_t);
+       iscsi_bsg_jobdone(job);
+       return DISPATCH_UNLOCKED;
+}
+
+/**
+ * iscsi_bsg_request_handler - generic handler for bsg requests
+ * @q:         request queue to manage
+ * @shost:     Scsi_Host related to the bsg object
+ * @dev:       device structure for bsg object
+ *
+ * NOTE: only shost messages are expected
+ */
+static void
+iscsi_bsg_request_handler(struct request_queue *q, struct Scsi_Host
*shost,
+                       struct device *dev)
+{
+       struct request *req;
+       struct iscsi_bsg_job *job;
+       enum iscsi_dispatch_result ret;
+
+       if (!get_device(dev))
+               return;
+
+       while (!blk_queue_plugged(q)) {
+
+               req = blk_fetch_request(q);
+               if (!req)
+                       break;
+
+               spin_unlock_irq(q->queue_lock);
+
+               ret = iscsi_req_to_bsgjob(req, shost);
+               if (ret) {
+                       req->errors = ret;
+                       blk_end_request(req, ret, blk_rq_bytes(req));
+                       spin_lock_irq(q->queue_lock);
+                       continue;
+               }
+
+               job = req->special;
+
+               /* check if we have the msgcode value at least */
+               if (job->request_len < sizeof(uint32_t)) {
+                       BUG_ON(job->reply_len < sizeof(uint32_t));
+                       job->reply->result = -ENOMSG;
+                       job->reply_len = sizeof(uint32_t);
+                       iscsi_bsg_jobdone(job);
+                       spin_lock_irq(q->queue_lock);
+                       continue;
+               }
+
+               /* the dispatch routines will unlock the queue_lock */
+               iscsi_bsg_host_dispatch(q, shost, job);
+
+               /* did dispatcher hit state that can't process any more */
+               if (ret == DISPATCH_BREAK)
+                       break;
+
+               /* did dispatcher had released the lock */
+               if (ret == DISPATCH_UNLOCKED)
+                       spin_lock_irq(q->queue_lock);
+       }
+
+       spin_unlock_irq(q->queue_lock);
+       put_device(dev);
+       spin_lock_irq(q->queue_lock);
+}
+
+/**
+ * iscsi_bsg_host_handler - handler for bsg requests for a iscsi host
+ * @q:         iscsi host request queue
+ */
+static void
+iscsi_bsg_host_handler(struct request_queue *q)
+{
+       struct Scsi_Host *shost = q->queuedata;
+
+       iscsi_bsg_request_handler(q, shost, &shost->shost_gendev);
+}
+
+/**
+ * iscsi_bsg_hostadd - Create and add the bsg hooks so we ...

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