Revert "[SCSI] libiscsi: Reduce locking contention in fast path"

BugLink: http://bugs.launchpad.net/bugs/1517142

This reverts commit 659743b0.
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

Conflicts:
	drivers/scsi/bnx2i/bnx2i_iscsi.c
	drivers/scsi/iscsi_tcp.c
	drivers/scsi/libiscsi.c

drivers/scsi/be2iscsi/be_main.c

@@ -232,20 +232,20 @@ static int beiscsi_eh_abort(struct scsi_cmnd *sc)
 	cls_session = starget_to_session(scsi_target(sc->device));
 	session = cls_session->dd_data;
 
-	spin_lock_bh(&session->frwd_lock);
+	spin_lock_bh(&session->lock);
 	if (!aborted_task || !aborted_task->sc) {
 		/* we raced */
-		spin_unlock_bh(&session->frwd_lock);
+		spin_unlock_bh(&session->lock);
 		return SUCCESS;
 	}
 
 	aborted_io_task = aborted_task->dd_data;
 	if (!aborted_io_task->scsi_cmnd) {
 		/* raced or invalid command */
-		spin_unlock_bh(&session->frwd_lock);
+		spin_unlock_bh(&session->lock);
 		return SUCCESS;
 	}
-	spin_unlock_bh(&session->frwd_lock);
+	spin_unlock_bh(&session->lock);
 	/* Invalidate WRB Posted for this Task */
 	AMAP_SET_BITS(struct amap_iscsi_wrb, invld,
 		      aborted_io_task->pwrb_handle->pwrb,
@@ -310,9 +310,9 @@ static int beiscsi_eh_device_reset(struct scsi_cmnd *sc)
 	/* invalidate iocbs */
 	cls_session = starget_to_session(scsi_target(sc->device));
 	session = cls_session->dd_data;
-	spin_lock_bh(&session->frwd_lock);
+	spin_lock_bh(&session->lock);
 	if (!session->leadconn || session->state != ISCSI_STATE_LOGGED_IN) {
-		spin_unlock_bh(&session->frwd_lock);
+		spin_unlock_bh(&session->lock);
 		return FAILED;
 	}
 	conn = session->leadconn;
@@ -341,7 +341,7 @@ static int beiscsi_eh_device_reset(struct scsi_cmnd *sc)
 		num_invalidate++;
 		inv_tbl++;
 	}
-	spin_unlock_bh(&session->frwd_lock);
+	spin_unlock_bh(&session->lock);
 	inv_tbl = phba->inv_tbl;
 
 	nonemb_cmd.va = pci_alloc_consistent(phba->ctrl.pdev,
@@ -1137,9 +1137,9 @@ beiscsi_process_async_pdu(struct beiscsi_conn *beiscsi_conn,
 		return 1;
 	}
 
-	spin_lock_bh(&session->back_lock);
+	spin_lock_bh(&session->lock);
 	__iscsi_complete_pdu(conn, (struct iscsi_hdr *)ppdu, pbuffer, buf_len);
-	spin_unlock_bh(&session->back_lock);
+	spin_unlock_bh(&session->lock);
 	return 0;
 }
 
@@ -1562,7 +1562,7 @@ static void hwi_complete_cmd(struct beiscsi_conn *beiscsi_conn,
 	pwrb = pwrb_handle->pwrb;
 	type = ((struct beiscsi_io_task *)task->dd_data)->wrb_type;
 
-	spin_lock_bh(&session->back_lock);
+	spin_lock_bh(&session->lock);
 	switch (type) {
 	case HWH_TYPE_IO:
 	case HWH_TYPE_IO_RD:
@@ -1601,7 +1601,7 @@ static void hwi_complete_cmd(struct beiscsi_conn *beiscsi_conn,
 		break;
 	}
 
-	spin_unlock_bh(&session->back_lock);
+	spin_unlock_bh(&session->lock);
 }
 
 static struct list_head *hwi_get_async_busy_list(struct hwi_async_pdu_context
@@ -4691,9 +4691,9 @@ beiscsi_offload_connection(struct beiscsi_conn *beiscsi_conn,
 	 * login/startup related tasks.
 	 */
 	beiscsi_conn->login_in_progress = 0;
-	spin_lock_bh(&session->back_lock);
+	spin_lock_bh(&session->lock);
 	beiscsi_cleanup_task(task);
-	spin_unlock_bh(&session->back_lock);
+	spin_unlock_bh(&session->lock);
 
 	pwrb_handle = alloc_wrb_handle(phba, beiscsi_conn->beiscsi_conn_cid,
 				       &pwrb_context);

drivers/scsi/bnx2i/bnx2i_hwi.c

@@ -1363,7 +1363,7 @@ int bnx2i_process_scsi_cmd_resp(struct iscsi_session *session,
 	u32 datalen = 0;
 
 	resp_cqe = (struct bnx2i_cmd_response *)cqe;
-	spin_lock_bh(&session->back_lock);
+	spin_lock_bh(&session->lock);
 	task = iscsi_itt_to_task(conn,
 				 resp_cqe->itt & ISCSI_CMD_RESPONSE_INDEX);
 	if (!task)
@@ -1434,7 +1434,7 @@ int bnx2i_process_scsi_cmd_resp(struct iscsi_session *session,
 	__iscsi_complete_pdu(conn, (struct iscsi_hdr *)hdr,
 			     conn->data, datalen);
 fail:
-	spin_unlock_bh(&session->back_lock);
+	spin_unlock_bh(&session->lock);
 	return 0;
 }
 
@@ -1459,7 +1459,7 @@ static int bnx2i_process_login_resp(struct iscsi_session *session,
 	int pad_len;
 
 	login = (struct bnx2i_login_response *) cqe;
-	spin_lock(&session->back_lock);
+	spin_lock(&session->lock);
 	task = iscsi_itt_to_task(conn,
 				 login->itt & ISCSI_LOGIN_RESPONSE_INDEX);
 	if (!task)
@@ -1502,7 +1502,7 @@ static int bnx2i_process_login_resp(struct iscsi_session *session,
 		bnx2i_conn->gen_pdu.resp_buf,
 		bnx2i_conn->gen_pdu.resp_wr_ptr - bnx2i_conn->gen_pdu.resp_buf);
 done:
-	spin_unlock(&session->back_lock);
+	spin_unlock(&session->lock);
 	return 0;
 }
 
@@ -1527,7 +1527,7 @@ static int bnx2i_process_text_resp(struct iscsi_session *session,
 	int pad_len;
 
 	text = (struct bnx2i_text_response *) cqe;
-	spin_lock(&session->back_lock);
+	spin_lock(&session->lock);
 	task = iscsi_itt_to_task(conn, text->itt & ISCSI_LOGIN_RESPONSE_INDEX);
 	if (!task)
 		goto done;
@@ -1563,7 +1563,7 @@ static int bnx2i_process_text_resp(struct iscsi_session *session,
 			     bnx2i_conn->gen_pdu.resp_wr_ptr -
 			     bnx2i_conn->gen_pdu.resp_buf);
 done:
-	spin_unlock(&session->back_lock);
+	spin_unlock(&session->lock);
 	return 0;
 }
 
@@ -1586,7 +1586,7 @@ static int bnx2i_process_tmf_resp(struct iscsi_session *session,
 	struct iscsi_tm_rsp *resp_hdr;
 
 	tmf_cqe = (struct bnx2i_tmf_response *)cqe;
-	spin_lock(&session->back_lock);
+	spin_lock(&session->lock);
 	task = iscsi_itt_to_task(conn,
 				 tmf_cqe->itt & ISCSI_TMF_RESPONSE_INDEX);
 	if (!task)
@@ -1602,7 +1602,7 @@ static int bnx2i_process_tmf_resp(struct iscsi_session *session,
 
 	__iscsi_complete_pdu(conn, (struct iscsi_hdr *)resp_hdr, NULL, 0);
 done:
-	spin_unlock(&session->back_lock);
+	spin_unlock(&session->lock);
 	return 0;
 }
 
@@ -1625,7 +1625,7 @@ static int bnx2i_process_logout_resp(struct iscsi_session *session,
 	struct iscsi_logout_rsp *resp_hdr;
 
 	logout = (struct bnx2i_logout_response *) cqe;
-	spin_lock(&session->back_lock);
+	spin_lock(&session->lock);
 	task = iscsi_itt_to_task(conn,
 				 logout->itt & ISCSI_LOGOUT_RESPONSE_INDEX);
 	if (!task)
@@ -1649,7 +1649,7 @@ static int bnx2i_process_logout_resp(struct iscsi_session *session,
 
 	bnx2i_conn->ep->state = EP_STATE_LOGOUT_RESP_RCVD;
 done:
-	spin_unlock(&session->back_lock);
+	spin_unlock(&session->lock);
 	return 0;
 }
 
@@ -1670,12 +1670,12 @@ static void bnx2i_process_nopin_local_cmpl(struct iscsi_session *session,
 	struct iscsi_task *task;
 
 	nop_in = (struct bnx2i_nop_in_msg *)cqe;
-	spin_lock(&session->back_lock);
+	spin_lock(&session->lock);
 	task = iscsi_itt_to_task(conn,
 				 nop_in->itt & ISCSI_NOP_IN_MSG_INDEX);
 	if (task)
 		__iscsi_put_task(task);
-	spin_unlock(&session->back_lock);
+	spin_unlock(&session->lock);
 }
 
 /**
@@ -1714,7 +1714,7 @@ static int bnx2i_process_nopin_mesg(struct iscsi_session *session,
 
 	nop_in = (struct bnx2i_nop_in_msg *)cqe;
 
-	spin_lock(&session->back_lock);
+	spin_lock(&session->lock);
 	hdr = (struct iscsi_nopin *)&bnx2i_conn->gen_pdu.resp_hdr;
 	memset(hdr, 0, sizeof(struct iscsi_hdr));
 	hdr->opcode = nop_in->op_code;
@@ -1740,7 +1740,7 @@ static int bnx2i_process_nopin_mesg(struct iscsi_session *session,
 	}
 done:
 	__iscsi_complete_pdu(conn, (struct iscsi_hdr *)hdr, NULL, 0);
-	spin_unlock(&session->back_lock);
+	spin_unlock(&session->lock);
 
 	return tgt_async_nop;
 }
@@ -1773,7 +1773,7 @@ static void bnx2i_process_async_mesg(struct iscsi_session *session,
 		return;
 	}
 
-	spin_lock(&session->back_lock);
+	spin_lock(&session->lock);
 	resp_hdr = (struct iscsi_async *) &bnx2i_conn->gen_pdu.resp_hdr;
 	memset(resp_hdr, 0, sizeof(struct iscsi_hdr));
 	resp_hdr->opcode = async_cqe->op_code;
@@ -1792,7 +1792,7 @@ static void bnx2i_process_async_mesg(struct iscsi_session *session,
 
 	__iscsi_complete_pdu(bnx2i_conn->cls_conn->dd_data,
 			     (struct iscsi_hdr *)resp_hdr, NULL, 0);
-	spin_unlock(&session->back_lock);
+	spin_unlock(&session->lock);
 }
 
 
@@ -1819,7 +1819,7 @@ static void bnx2i_process_reject_mesg(struct iscsi_session *session,
 	} else
 		bnx2i_unsol_pdu_adjust_rq(bnx2i_conn);
 
-	spin_lock(&session->back_lock);
+	spin_lock(&session->lock);
 	hdr = (struct iscsi_reject *) &bnx2i_conn->gen_pdu.resp_hdr;
 	memset(hdr, 0, sizeof(struct iscsi_hdr));
 	hdr->opcode = reject->op_code;
@@ -1830,7 +1830,7 @@ static void bnx2i_process_reject_mesg(struct iscsi_session *session,
 	hdr->ffffffff = cpu_to_be32(RESERVED_ITT);
 	__iscsi_complete_pdu(conn, (struct iscsi_hdr *)hdr, conn->data,
 			     reject->data_length);
-	spin_unlock(&session->back_lock);
+	spin_unlock(&session->lock);
 }
 
 /**
@@ -1850,13 +1850,13 @@ static void bnx2i_process_cmd_cleanup_resp(struct iscsi_session *session,
 	struct iscsi_task *task;
 
 	cmd_clean_rsp = (struct bnx2i_cleanup_response *)cqe;
-	spin_lock(&session->back_lock);
+	spin_lock(&session->lock);
 	task = iscsi_itt_to_task(conn,
 			cmd_clean_rsp->itt & ISCSI_CLEANUP_RESPONSE_INDEX);
 	if (!task)
 		printk(KERN_ALERT "bnx2i: cmd clean ITT %x not active\n",
 			cmd_clean_rsp->itt & ISCSI_CLEANUP_RESPONSE_INDEX);
-	spin_unlock(&session->back_lock);
+	spin_unlock(&session->lock);
 	complete(&bnx2i_conn->cmd_cleanup_cmpl);
 }
 
@@ -1923,11 +1923,11 @@ static int bnx2i_queue_scsi_cmd_resp(struct iscsi_session *session,
 	int rc = 0;
 	int cpu;
 
-	spin_lock(&session->back_lock);
+	spin_lock(&session->lock);
 	task = iscsi_itt_to_task(bnx2i_conn->cls_conn->dd_data,
 				 cqe->itt & ISCSI_CMD_RESPONSE_INDEX);
 	if (!task || !task->sc) {
-		spin_unlock(&session->back_lock);
+		spin_unlock(&session->lock);
 		return -EINVAL;
 	}
 	sc = task->sc;
@@ -1937,7 +1937,7 @@ static int bnx2i_queue_scsi_cmd_resp(struct iscsi_session *session,
 	else
 		cpu = sc->request->cpu;
 
-	spin_unlock(&session->back_lock);
+	spin_unlock(&session->lock);
 
 	p = &per_cpu(bnx2i_percpu, cpu);
 	spin_lock(&p->p_work_lock);

drivers/scsi/bnx2i/bnx2i_iscsi.c

@@ -1172,12 +1172,10 @@ static void bnx2i_cleanup_task(struct iscsi_task *task)
 	if (task->state == ISCSI_TASK_ABRT_TMF) {
 		bnx2i_send_cmd_cleanup_req(hba, task->dd_data);
 
-		spin_unlock_bh(&conn->session->back_lock);
-		spin_unlock_bh(&conn->session->frwd_lock);
+		spin_unlock_bh(&conn->session->lock);
 		wait_for_completion_timeout(&bnx2i_conn->cmd_cleanup_cmpl,
 				msecs_to_jiffies(ISCSI_CMD_CLEANUP_TIMEOUT));
-		spin_lock_bh(&conn->session->frwd_lock);
-		spin_lock_bh(&conn->session->back_lock);
+		spin_lock_bh(&conn->session->lock);
 	}
 	bnx2i_iscsi_unmap_sg_list(task->dd_data);
 }
@@ -2063,7 +2061,7 @@ int bnx2i_hw_ep_disconnect(struct bnx2i_endpoint *bnx2i_ep)
 		goto out;
 
 	if (session) {
-		spin_lock_bh(&session->frwd_lock);
+		spin_lock_bh(&session->lock);
 		if (bnx2i_ep->state != EP_STATE_TCP_FIN_RCVD) {
 			if (session->state == ISCSI_STATE_LOGGING_OUT) {
 				if (bnx2i_ep->state == EP_STATE_LOGOUT_SENT) {
@@ -2079,7 +2077,7 @@ int bnx2i_hw_ep_disconnect(struct bnx2i_endpoint *bnx2i_ep)
 		} else
 			close = 1;
 
-		spin_unlock_bh(&session->frwd_lock);
+		spin_unlock_bh(&session->lock);
 	}
 
 	bnx2i_ep->state = EP_STATE_DISCONN_START;

drivers/scsi/iscsi_tcp.c

@@ -593,9 +593,9 @@ static void iscsi_sw_tcp_release_conn(struct iscsi_conn *conn)
 	iscsi_sw_tcp_conn_restore_callbacks(conn);
 	sock_put(sock->sk);
 
-	spin_lock_bh(&session->frwd_lock);
+	spin_lock_bh(&session->lock);
 	tcp_sw_conn->sock = NULL;
-	spin_unlock_bh(&session->frwd_lock);
+	spin_unlock_bh(&session->lock);
 	sockfd_put(sock);
 }
 
@@ -663,10 +663,10 @@ iscsi_sw_tcp_conn_bind(struct iscsi_cls_session *cls_session,
 	if (err)
 		goto free_socket;
 
-	spin_lock_bh(&session->frwd_lock);
+	spin_lock_bh(&session->lock);
 	/* bind iSCSI connection and socket */
 	tcp_sw_conn->sock = sock;
-	spin_unlock_bh(&session->frwd_lock);
+	spin_unlock_bh(&session->lock);
 
 	/* setup Socket parameters */
 	sk = sock->sk;
@@ -727,9 +727,9 @@ static int iscsi_sw_tcp_conn_get_param(struct iscsi_cls_conn *cls_conn,
 	case ISCSI_PARAM_CONN_PORT:
 	case ISCSI_PARAM_CONN_ADDRESS:
 	case ISCSI_PARAM_LOCAL_PORT:
-		spin_lock_bh(&conn->session->frwd_lock);
+		spin_lock_bh(&conn->session->lock);
 		if (!tcp_sw_conn || !tcp_sw_conn->sock) {
-			spin_unlock_bh(&conn->session->frwd_lock);
+			spin_unlock_bh(&conn->session->lock);
 			return -ENOTCONN;
 		}
 		if (param == ISCSI_PARAM_LOCAL_PORT)
@@ -738,7 +738,7 @@ static int iscsi_sw_tcp_conn_get_param(struct iscsi_cls_conn *cls_conn,
 		else
 			rc = kernel_getpeername(tcp_sw_conn->sock,
 						(struct sockaddr *)&addr, &len);
-		spin_unlock_bh(&conn->session->frwd_lock);
+		spin_unlock_bh(&conn->session->lock);
 		if (rc)
 			return rc;
 
@@ -767,23 +767,23 @@ static int iscsi_sw_tcp_host_get_param(struct Scsi_Host *shost,
 		if (!session)
 			return -ENOTCONN;
 
-		spin_lock_bh(&session->frwd_lock);
+		spin_lock_bh(&session->lock);
 		conn = session->leadconn;
 		if (!conn) {
-			spin_unlock_bh(&session->frwd_lock);
+			spin_unlock_bh(&session->lock);
 			return -ENOTCONN;
 		}
 		tcp_conn = conn->dd_data;
 
 		tcp_sw_conn = tcp_conn->dd_data;
 		if (!tcp_sw_conn->sock) {
-			spin_unlock_bh(&session->frwd_lock);
+			spin_unlock_bh(&session->lock);
 			return -ENOTCONN;
 		}
 
 		rc = kernel_getsockname(tcp_sw_conn->sock,
 					(struct sockaddr *)&addr, &len);
-		spin_unlock_bh(&session->frwd_lock);
+		spin_unlock_bh(&session->lock);
 		if (rc)
 			return rc;
 

drivers/scsi/libiscsi_tcp.c

@@ -446,7 +446,7 @@ iscsi_tcp_data_recv_prep(struct iscsi_tcp_conn *tcp_conn)
  * iscsi_tcp_cleanup_task - free tcp_task resources
  * @task: iscsi task
  *
- * must be called with session back_lock
+ * must be called with session lock
  */
 void iscsi_tcp_cleanup_task(struct iscsi_task *task)
 {
@@ -457,7 +457,6 @@ void iscsi_tcp_cleanup_task(struct iscsi_task *task)
 	if (!task->sc)
 		return;
 
-	spin_lock_bh(&tcp_task->queue2pool);
 	/* flush task's r2t queues */
 	while (kfifo_out(&tcp_task->r2tqueue, (void*)&r2t, sizeof(void*))) {
 		kfifo_in(&tcp_task->r2tpool.queue, (void*)&r2t,
@@ -471,7 +470,6 @@ void iscsi_tcp_cleanup_task(struct iscsi_task *task)
 			    sizeof(void*));
 		tcp_task->r2t = NULL;
 	}
-	spin_unlock_bh(&tcp_task->queue2pool);
 }
 EXPORT_SYMBOL_GPL(iscsi_tcp_cleanup_task);
 
@@ -579,13 +577,11 @@ static int iscsi_tcp_r2t_rsp(struct iscsi_conn *conn, struct iscsi_task *task)
 		return ISCSI_ERR_DATALEN;
 	}
 
-	spin_lock(&tcp_task->pool2queue);
 	rc = kfifo_out(&tcp_task->r2tpool.queue, (void *)&r2t, sizeof(void *));
 	if (!rc) {
 		iscsi_conn_printk(KERN_ERR, conn, "Could not allocate R2T. "
 				  "Target has sent more R2Ts than it "
 				  "negotiated for or driver has leaked.\n");
-		spin_unlock(&tcp_task->pool2queue);
 		return ISCSI_ERR_PROTO;
 	}
 
@@ -600,7 +596,6 @@ static int iscsi_tcp_r2t_rsp(struct iscsi_conn *conn, struct iscsi_task *task)
 	tcp_task->exp_datasn = r2tsn + 1;
 	kfifo_in(&tcp_task->r2tqueue, (void*)&r2t, sizeof(void*));
 	conn->r2t_pdus_cnt++;
-	spin_unlock(&tcp_task->pool2queue);
 
 	iscsi_requeue_task(task);
 	return 0;
@@ -673,14 +668,14 @@ iscsi_tcp_hdr_dissect(struct iscsi_conn *conn, struct iscsi_hdr *hdr)
 
 	switch(opcode) {
 	case ISCSI_OP_SCSI_DATA_IN:
-		spin_lock(&conn->session->back_lock);
+		spin_lock(&conn->session->lock);
 		task = iscsi_itt_to_ctask(conn, hdr->itt);
 		if (!task)
 			rc = ISCSI_ERR_BAD_ITT;
 		else
 			rc = iscsi_tcp_data_in(conn, task);
 		if (rc) {
-			spin_unlock(&conn->session->back_lock);
+			spin_unlock(&conn->session->lock);
 			break;
 		}
 
@@ -713,11 +708,11 @@ iscsi_tcp_hdr_dissect(struct iscsi_conn *conn, struct iscsi_hdr *hdr)
 						   tcp_conn->in.datalen,
 						   iscsi_tcp_process_data_in,
 						   rx_hash);
-			spin_unlock(&conn->session->back_lock);
+			spin_unlock(&conn->session->lock);
 			return rc;
 		}
 		rc = __iscsi_complete_pdu(conn, hdr, NULL, 0);
-		spin_unlock(&conn->session->back_lock);
+		spin_unlock(&conn->session->lock);
 		break;
 	case ISCSI_OP_SCSI_CMD_RSP:
 		if (tcp_conn->in.datalen) {
@@ -727,20 +722,18 @@ iscsi_tcp_hdr_dissect(struct iscsi_conn *conn, struct iscsi_hdr *hdr)
 		rc = iscsi_complete_pdu(conn, hdr, NULL, 0);
 		break;
 	case ISCSI_OP_R2T:
-		spin_lock(&conn->session->back_lock);
+		spin_lock(&conn->session->lock);
 		task = iscsi_itt_to_ctask(conn, hdr->itt);
-		spin_unlock(&conn->session->back_lock);
 		if (!task)
 			rc = ISCSI_ERR_BAD_ITT;
 		else if (ahslen)
 			rc = ISCSI_ERR_AHSLEN;
 		else if (task->sc->sc_data_direction == DMA_TO_DEVICE) {
 			task->last_xfer = jiffies;
-			spin_lock(&conn->session->frwd_lock);
 			rc = iscsi_tcp_r2t_rsp(conn, task);
-			spin_unlock(&conn->session->frwd_lock);
 		} else
 			rc = ISCSI_ERR_PROTO;
+		spin_unlock(&conn->session->lock);
 		break;
 	case ISCSI_OP_LOGIN_RSP:
 	case ISCSI_OP_TEXT_RSP:
@@ -988,13 +981,14 @@ EXPORT_SYMBOL_GPL(iscsi_tcp_task_init);
 
 static struct iscsi_r2t_info *iscsi_tcp_get_curr_r2t(struct iscsi_task *task)
 {
+	struct iscsi_session *session = task->conn->session;
 	struct iscsi_tcp_task *tcp_task = task->dd_data;
 	struct iscsi_r2t_info *r2t = NULL;
 
 	if (iscsi_task_has_unsol_data(task))
 		r2t = &task->unsol_r2t;
 	else {
-		spin_lock_bh(&tcp_task->queue2pool);
+		spin_lock_bh(&session->lock);
 		if (tcp_task->r2t) {
 			r2t = tcp_task->r2t;
 			/* Continue with this R2T? */
@@ -1016,7 +1010,7 @@ static struct iscsi_r2t_info *iscsi_tcp_get_curr_r2t(struct iscsi_task *task)
 			else
 				r2t = tcp_task->r2t;
 		}
-		spin_unlock_bh(&tcp_task->queue2pool);
+		spin_unlock_bh(&session->lock);
 	}
 
 	return r2t;
@@ -1146,8 +1140,6 @@ int iscsi_tcp_r2tpool_alloc(struct iscsi_session *session)
 			iscsi_pool_free(&tcp_task->r2tpool);
 			goto r2t_alloc_fail;
 		}
-		spin_lock_init(&tcp_task->pool2queue);
-		spin_lock_init(&tcp_task->queue2pool);
 	}
 
 	return 0;

drivers/scsi/qla4xxx/ql4_isr.c

@@ -385,9 +385,9 @@ static void qla4xxx_passthru_status_entry(struct scsi_qla_host *ha,
 
 	cls_conn = ddb_entry->conn;
 	conn = cls_conn->dd_data;
-	spin_lock(&conn->session->back_lock);
+	spin_lock(&conn->session->lock);
 	task = iscsi_itt_to_task(conn, itt);
-	spin_unlock(&conn->session->back_lock);
+	spin_unlock(&conn->session->lock);
 
 	if (task == NULL) {
 		ql4_printk(KERN_ERR, ha, "%s: Task is NULL\n", __func__);

include/scsi/libiscsi.h

@@ -331,19 +331,12 @@ struct iscsi_session {
 	struct iscsi_transport	*tt;
 	struct Scsi_Host	*host;
 	struct iscsi_conn	*leadconn;	/* leading connection */
-	/* Between the forward and the backward locks exists a strict locking
-	 * hierarchy. The mutual exclusion zone protected by the forward lock
-	 * can enclose the mutual exclusion zone protected by the backward lock
-	 * but not vice versa.
-	 */
-	spinlock_t		frwd_lock;	/* protects session state, *
-						 * cmdsn, queued_cmdsn     *
+	spinlock_t		lock;		/* protects session state, *
+						 * sequence numbers,       *
 						 * session resources:      *
-						 * - cmdpool kfifo_out ,   *
-						 * - mgmtpool,		   */
-	spinlock_t		back_lock;	/* protects cmdsn_exp      *
-						 * cmdsn_max,              *
-						 * cmdpool kfifo_in        */
+						 * - cmdpool,		   *
+						 * - mgmtpool,		   *
+						 * - r2tpool		   */
 	int			state;		/* session state           */
 	int			age;		/* counts session re-opens */
 

include/scsi/libiscsi_tcp.h

@@ -83,8 +83,6 @@ struct iscsi_tcp_task {
 	struct iscsi_pool	r2tpool;
 	struct kfifo		r2tqueue;
 	void			*dd_data;
-	spinlock_t		pool2queue;
-	spinlock_t		queue2pool;
 };
 
 enum {