IB/iser: Use libiscsi passthrough mode

libiscsi passthrough mode invokes the transport xmit calls directly
without first going through an internal queue, unlike the other mode,
which uses a queue and a xmitworker thread.  Now that the "cant_sleep"
prerequisite of iscsi_host_alloc is met, move to use it.  Handling
xmit errors is now done by the passthrough flow of libiscsi.  Since
the queue/worker aren't used in this mode, the code that schedules the
xmitworker is removed.
Signed-off-by: NOr Gerlitz <ogerlitz@voltaire.com>
Reviewed-by: NMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

drivers/infiniband/ulp/iser/iscsi_iser.c

@@ -190,7 +190,7 @@ iscsi_iser_mtask_xmit(struct iscsi_conn *conn, struct iscsi_task *task)
 {
 	int error = 0;
 
-	iser_dbg("task deq [cid %d itt 0x%x]\n", conn->id, task->itt);
+	iser_dbg("mtask xmit [cid %d itt 0x%x]\n", conn->id, task->itt);
 
 	error = iser_send_control(conn, task);
 
@@ -200,9 +200,6 @@ iscsi_iser_mtask_xmit(struct iscsi_conn *conn, struct iscsi_task *task)
 	 * - if yes, the task is recycled at iscsi_complete_pdu
 	 * - if no,  the task is recycled at iser_snd_completion
 	 */
-	if (error && error != -ENOBUFS)
-		iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
-
 	return error;
 }
 
@@ -254,7 +251,7 @@ iscsi_iser_task_xmit(struct iscsi_task *task)
 			   task->imm_count, task->unsol_r2t.data_length);
 	}
 
-	iser_dbg("task deq [cid %d itt 0x%x]\n",
+	iser_dbg("ctask xmit [cid %d itt 0x%x]\n",
 		   conn->id, task->itt);
 
 	/* Send the cmd PDU */
@@ -270,8 +267,6 @@ iscsi_iser_task_xmit(struct iscsi_task *task)
 		error = iscsi_iser_task_xmit_unsol_data(conn, task);
 
  iscsi_iser_task_xmit_exit:
-	if (error && error != -ENOBUFS)
-		iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
 	return error;
 }
 
@@ -423,7 +418,7 @@ iscsi_iser_session_create(struct iscsi_endpoint *ep,
 	struct Scsi_Host *shost;
 	struct iser_conn *ib_conn;
 
-	shost = iscsi_host_alloc(&iscsi_iser_sht, 0, 1);
+	shost = iscsi_host_alloc(&iscsi_iser_sht, 0, 0);
 	if (!shost)
 		return NULL;
 	shost->transportt = iscsi_iser_scsi_transport;

drivers/infiniband/ulp/iser/iser_initiator.c

@@ -514,10 +514,7 @@ void iser_rcv_completion(struct iser_rx_desc *rx_desc,
 void iser_snd_completion(struct iser_tx_desc *tx_desc,
 			struct iser_conn *ib_conn)
 {
-	struct iscsi_iser_conn *iser_conn = ib_conn->iser_conn;
-	struct iscsi_conn      *conn = iser_conn->iscsi_conn;
 	struct iscsi_task *task;
-	int resume_tx = 0;
 	struct iser_device *device = ib_conn->device;
 
 	if (tx_desc->type == ISCSI_TX_DATAOUT) {
@@ -526,17 +523,8 @@ void iser_snd_completion(struct iser_tx_desc *tx_desc,
 		kmem_cache_free(ig.desc_cache, tx_desc);
 	}
 
-	if (atomic_read(&iser_conn->ib_conn->post_send_buf_count) ==
-	    ISER_QP_MAX_REQ_DTOS)
-		resume_tx = 1;
-
 	atomic_dec(&ib_conn->post_send_buf_count);
 
-	if (resume_tx) {
-		iser_dbg("%ld resuming tx\n",jiffies);
-		iscsi_conn_queue_work(conn);
-	}
-
 	if (tx_desc->type == ISCSI_TX_CONTROL) {
 		/* this arithmetic is legal by libiscsi dd_data allocation */
 		task = (void *) ((long)(void *)tx_desc -