iscsi/iser-target: Fix isert_conn->state hung shutdown issues

This patch addresses a couple of different hug shutdown issues
related to wait_event() + isert_conn->state.  First, it changes
isert_conn->conn_wait + isert_conn->conn_wait_comp_err from
waitqueues to completions, and sets ISER_CONN_TERMINATING from
within isert_disconnect_work().

Second, it splits isert_free_conn() into isert_wait_conn() that
is called earlier in iscsit_close_connection() to ensure that
all outstanding commands have completed before continuing.

Finally, it breaks isert_cq_comp_err() into seperate TX / RX
related code, and adds logic in isert_cq_rx_comp_err() to wait
for outstanding commands to complete before setting ISER_CONN_DOWN
and calling complete(&isert_conn->conn_wait_comp_err).

Acked-by: Sagi Grimberg <sagig@mellanox.com>
Cc: Or Gerlitz <ogerlitz@mellanox.com>
Cc: <stable@vger.kernel.org> #3.10+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

drivers/infiniband/ulp/isert/ib_isert.c

@@ -492,8 +492,8 @@ isert_connect_request(struct rdma_cm_id *cma_id, struct rdma_cm_event *event)
 	isert_conn->state = ISER_CONN_INIT;
 	INIT_LIST_HEAD(&isert_conn->conn_accept_node);
 	init_completion(&isert_conn->conn_login_comp);
-	init_waitqueue_head(&isert_conn->conn_wait);
-	init_waitqueue_head(&isert_conn->conn_wait_comp_err);
+	init_completion(&isert_conn->conn_wait);
+	init_completion(&isert_conn->conn_wait_comp_err);
 	kref_init(&isert_conn->conn_kref);
 	kref_get(&isert_conn->conn_kref);
 	mutex_init(&isert_conn->conn_mutex);
@@ -688,11 +688,11 @@ isert_disconnect_work(struct work_struct *work)
 
 	pr_debug("isert_disconnect_work(): >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
 	mutex_lock(&isert_conn->conn_mutex);
-	isert_conn->state = ISER_CONN_DOWN;
+	if (isert_conn->state == ISER_CONN_UP)
+		isert_conn->state = ISER_CONN_TERMINATING;
 
 	if (isert_conn->post_recv_buf_count == 0 &&
 	    atomic_read(&isert_conn->post_send_buf_count) == 0) {
-		pr_debug("Calling wake_up(&isert_conn->conn_wait);\n");
 		mutex_unlock(&isert_conn->conn_mutex);
 		goto wake_up;
 	}
@@ -712,7 +712,7 @@ isert_disconnect_work(struct work_struct *work)
 	mutex_unlock(&isert_conn->conn_mutex);
 
 wake_up:
-	wake_up(&isert_conn->conn_wait);
+	complete(&isert_conn->conn_wait);
 	isert_put_conn(isert_conn);
 }
 
@@ -1589,7 +1589,7 @@ isert_do_control_comp(struct work_struct *work)
 		pr_debug("Calling iscsit_logout_post_handler >>>>>>>>>>>>>>\n");
 		/*
 		 * Call atomic_dec(&isert_conn->post_send_buf_count)
-		 * from isert_free_conn()
+		 * from isert_wait_conn()
 		 */
 		isert_conn->logout_posted = true;
 		iscsit_logout_post_handler(cmd, cmd->conn);
@@ -1691,31 +1691,39 @@ isert_send_completion(struct iser_tx_desc *tx_desc,
 }
 
 static void
-isert_cq_comp_err(struct iser_tx_desc *tx_desc, struct isert_conn *isert_conn)
+isert_cq_tx_comp_err(struct iser_tx_desc *tx_desc, struct isert_conn *isert_conn)
 {
 	struct ib_device *ib_dev = isert_conn->conn_cm_id->device;
+	struct isert_cmd *isert_cmd = tx_desc->isert_cmd;
+
+	if (!isert_cmd)
+		isert_unmap_tx_desc(tx_desc, ib_dev);
+	else
+		isert_completion_put(tx_desc, isert_cmd, ib_dev);
+}
+
+static void
+isert_cq_rx_comp_err(struct isert_conn *isert_conn)
+{
+	struct ib_device *ib_dev = isert_conn->conn_cm_id->device;
+	struct iscsi_conn *conn = isert_conn->conn;
 
-	if (tx_desc) {
-		struct isert_cmd *isert_cmd = tx_desc->isert_cmd;
+	if (isert_conn->post_recv_buf_count)
+		return;
 
-		if (!isert_cmd)
-			isert_unmap_tx_desc(tx_desc, ib_dev);
-		else
-			isert_completion_put(tx_desc, isert_cmd, ib_dev);
+	if (conn->sess) {
+		target_sess_cmd_list_set_waiting(conn->sess->se_sess);
+		target_wait_for_sess_cmds(conn->sess->se_sess);
 	}
 
-	if (isert_conn->post_recv_buf_count == 0 &&
-	    atomic_read(&isert_conn->post_send_buf_count) == 0) {
-		pr_debug("isert_cq_comp_err >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
-		pr_debug("Calling wake_up from isert_cq_comp_err\n");
+	while (atomic_read(&isert_conn->post_send_buf_count))
+		msleep(3000);
 
-		mutex_lock(&isert_conn->conn_mutex);
-		if (isert_conn->state != ISER_CONN_DOWN)
-			isert_conn->state = ISER_CONN_TERMINATING;
-		mutex_unlock(&isert_conn->conn_mutex);
+	mutex_lock(&isert_conn->conn_mutex);
+	isert_conn->state = ISER_CONN_DOWN;
+	mutex_unlock(&isert_conn->conn_mutex);
 
-		wake_up(&isert_conn->conn_wait_comp_err);
-	}
+	complete(&isert_conn->conn_wait_comp_err);
 }
 
 static void
@@ -1740,8 +1748,9 @@ isert_cq_tx_work(struct work_struct *work)
 			pr_debug("TX wc.status != IB_WC_SUCCESS >>>>>>>>>>>>>>\n");
 			pr_debug("TX wc.status: 0x%08x\n", wc.status);
 			pr_debug("TX wc.vendor_err: 0x%08x\n", wc.vendor_err);
+
 			atomic_dec(&isert_conn->post_send_buf_count);
-			isert_cq_comp_err(tx_desc, isert_conn);
+			isert_cq_tx_comp_err(tx_desc, isert_conn);
 		}
 	}
 
@@ -1784,7 +1793,7 @@ isert_cq_rx_work(struct work_struct *work)
 					 wc.vendor_err);
 			}
 			isert_conn->post_recv_buf_count--;
-			isert_cq_comp_err(NULL, isert_conn);
+			isert_cq_rx_comp_err(isert_conn);
 		}
 	}
 
@@ -2702,22 +2711,11 @@ isert_free_np(struct iscsi_np *np)
 	kfree(isert_np);
 }
 
-static int isert_check_state(struct isert_conn *isert_conn, int state)
-{
-	int ret;
-
-	mutex_lock(&isert_conn->conn_mutex);
-	ret = (isert_conn->state == state);
-	mutex_unlock(&isert_conn->conn_mutex);
-
-	return ret;
-}
-
-static void isert_free_conn(struct iscsi_conn *conn)
+static void isert_wait_conn(struct iscsi_conn *conn)
 {
 	struct isert_conn *isert_conn = conn->context;
 
-	pr_debug("isert_free_conn: Starting \n");
+	pr_debug("isert_wait_conn: Starting \n");
 	/*
 	 * Decrement post_send_buf_count for special case when called
 	 * from isert_do_control_comp() -> iscsit_logout_post_handler()
@@ -2727,38 +2725,29 @@ static void isert_free_conn(struct iscsi_conn *conn)
 		atomic_dec(&isert_conn->post_send_buf_count);
 
 	if (isert_conn->conn_cm_id && isert_conn->state != ISER_CONN_DOWN) {
-		pr_debug("Calling rdma_disconnect from isert_free_conn\n");
+		pr_debug("Calling rdma_disconnect from isert_wait_conn\n");
 		rdma_disconnect(isert_conn->conn_cm_id);
 	}
 	/*
 	 * Only wait for conn_wait_comp_err if the isert_conn made it
 	 * into full feature phase..
 	 */
-	if (isert_conn->state == ISER_CONN_UP) {
-		pr_debug("isert_free_conn: Before wait_event comp_err %d\n",
-			 isert_conn->state);
-		mutex_unlock(&isert_conn->conn_mutex);
-
-		wait_event(isert_conn->conn_wait_comp_err,
-			  (isert_check_state(isert_conn, ISER_CONN_TERMINATING)));
-
-		wait_event(isert_conn->conn_wait,
-			  (isert_check_state(isert_conn, ISER_CONN_DOWN)));
-
-		isert_put_conn(isert_conn);
-		return;
-	}
 	if (isert_conn->state == ISER_CONN_INIT) {
 		mutex_unlock(&isert_conn->conn_mutex);
-		isert_put_conn(isert_conn);
 		return;
 	}
-	pr_debug("isert_free_conn: wait_event conn_wait %d\n",
-		 isert_conn->state);
+	if (isert_conn->state == ISER_CONN_UP)
+		isert_conn->state = ISER_CONN_TERMINATING;
 	mutex_unlock(&isert_conn->conn_mutex);
 
-	wait_event(isert_conn->conn_wait,
-		  (isert_check_state(isert_conn, ISER_CONN_DOWN)));
+	wait_for_completion(&isert_conn->conn_wait_comp_err);
+
+	wait_for_completion(&isert_conn->conn_wait);
+}
+
+static void isert_free_conn(struct iscsi_conn *conn)
+{
+	struct isert_conn *isert_conn = conn->context;
 
 	isert_put_conn(isert_conn);
 }
@@ -2771,6 +2760,7 @@ static struct iscsit_transport iser_target_transport = {
 	.iscsit_setup_np	= isert_setup_np,
 	.iscsit_accept_np	= isert_accept_np,
 	.iscsit_free_np		= isert_free_np,
+	.iscsit_wait_conn	= isert_wait_conn,
 	.iscsit_free_conn	= isert_free_conn,
 	.iscsit_get_login_rx	= isert_get_login_rx,
 	.iscsit_put_login_tx	= isert_put_login_tx,

drivers/infiniband/ulp/isert/ib_isert.h

@@ -116,8 +116,8 @@ struct isert_conn {
 	struct isert_device	*conn_device;
 	struct work_struct	conn_logout_work;
 	struct mutex		conn_mutex;
-	wait_queue_head_t	conn_wait;
-	wait_queue_head_t	conn_wait_comp_err;
+	struct completion	conn_wait;
+	struct completion	conn_wait_comp_err;
 	struct kref		conn_kref;
 	struct list_head	conn_fr_pool;
 	int			conn_fr_pool_size;

drivers/target/iscsi/iscsi_target.c

@@ -4196,6 +4196,10 @@ int iscsit_close_connection(
 	iscsit_stop_timers_for_cmds(conn);
 	iscsit_stop_nopin_response_timer(conn);
 	iscsit_stop_nopin_timer(conn);
+
+	if (conn->conn_transport->iscsit_wait_conn)
+		conn->conn_transport->iscsit_wait_conn(conn);
+
 	iscsit_free_queue_reqs_for_conn(conn);
 
 	/*

include/target/iscsi/iscsi_transport.h

@@ -12,6 +12,7 @@ struct iscsit_transport {
 	int (*iscsit_setup_np)(struct iscsi_np *, struct __kernel_sockaddr_storage *);
 	int (*iscsit_accept_np)(struct iscsi_np *, struct iscsi_conn *);
 	void (*iscsit_free_np)(struct iscsi_np *);
+	void (*iscsit_wait_conn)(struct iscsi_conn *);
 	void (*iscsit_free_conn)(struct iscsi_conn *);
 	int (*iscsit_get_login_rx)(struct iscsi_conn *, struct iscsi_login *);
 	int (*iscsit_put_login_tx)(struct iscsi_conn *, struct iscsi_login *, u32);