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Commit b2cb9649 authored by Nicholas Bellinger's avatar Nicholas Bellinger
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iser-target: Fix session reset bug with RDMA_CM_EVENT_DISCONNECTED 



This patch addresses a bug where RDMA_CM_EVENT_DISCONNECTED may occur
before the connection shutdown has been completed by rx/tx threads,
that causes isert_free_conn() to wait indefinately on ->conn_wait.

This patch allows isert_disconnect_work code to invoke rdma_disconnect
when isert_disconnect_work() process context is started by client
session reset before isert_free_conn() code has been reached.

It also adds isert_conn->conn_mutex protection for ->state within
isert_disconnect_work(), isert_cq_comp_err() and isert_free_conn()
code, along with isert_check_state() for wait_event usage.

(v2: Add explicit iscsit_cause_connection_reinstatement call
     during isert_disconnect_work() to force conn reset)

Cc: stable@vger.kernel.org  # 3.10+
Cc: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
parent 186a9647

drivers/infiniband/ulp/isert/ib_isert.c

+60 −10
Original line number Original line Diff line number Diff line
@@ -388,6 +388,7 @@ isert_connect_request(struct rdma_cm_id *cma_id, struct rdma_cm_event *event) 
	init_waitqueue_head(&isert_conn->conn_wait_comp_err);

	init_waitqueue_head(&isert_conn->conn_wait_comp_err);

	kref_init(&isert_conn->conn_kref);

	kref_init(&isert_conn->conn_kref);

	kref_get(&isert_conn->conn_kref);

	kref_get(&isert_conn->conn_kref);

	mutex_init(&isert_conn->conn_mutex);





	cma_id->context = isert_conn;

	cma_id->context = isert_conn;

	isert_conn->conn_cm_id = cma_id;

	isert_conn->conn_cm_id = cma_id;
@@ -540,15 +541,32 @@ isert_disconnect_work(struct work_struct *work) 
				struct isert_conn, conn_logout_work);

				struct isert_conn, conn_logout_work);





	pr_debug("isert_disconnect_work(): >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");

	pr_debug("isert_disconnect_work(): >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");



	mutex_lock(&isert_conn->conn_mutex);

	isert_conn->state = ISER_CONN_DOWN;

	isert_conn->state = ISER_CONN_DOWN;





	if (isert_conn->post_recv_buf_count == 0 &&

	if (isert_conn->post_recv_buf_count == 0 &&

	    atomic_read(&isert_conn->post_send_buf_count) == 0) {

	    atomic_read(&isert_conn->post_send_buf_count) == 0) {

		pr_debug("Calling wake_up(&isert_conn->conn_wait);\n");

		pr_debug("Calling wake_up(&isert_conn->conn_wait);\n");

		wake_up(&isert_conn->conn_wait);

		mutex_unlock(&isert_conn->conn_mutex);

		goto wake_up;

	}

	if (!isert_conn->conn_cm_id) {

		mutex_unlock(&isert_conn->conn_mutex);

		isert_put_conn(isert_conn);

		return;

	}

	if (!isert_conn->logout_posted) {

		pr_debug("Calling rdma_disconnect for !logout_posted from"

			 " isert_disconnect_work\n");

		rdma_disconnect(isert_conn->conn_cm_id);

		mutex_unlock(&isert_conn->conn_mutex);

		iscsit_cause_connection_reinstatement(isert_conn->conn, 0);

		goto wake_up;

	}

	}

	mutex_unlock(&isert_conn->conn_mutex);





wake_up:

	wake_up(&isert_conn->conn_wait);

	isert_put_conn(isert_conn);

	isert_put_conn(isert_conn);

}

}
@@ -1439,7 +1457,11 @@ isert_cq_comp_err(struct iser_tx_desc *tx_desc, struct isert_conn *isert_conn) 
		pr_debug("isert_cq_comp_err >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");

		pr_debug("isert_cq_comp_err >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");

		pr_debug("Calling wake_up from isert_cq_comp_err\n");

		pr_debug("Calling wake_up from isert_cq_comp_err\n");





		mutex_lock(&isert_conn->conn_mutex);

		if (isert_conn->state != ISER_CONN_DOWN)

			isert_conn->state = ISER_CONN_TERMINATING;

			isert_conn->state = ISER_CONN_TERMINATING;

		mutex_unlock(&isert_conn->conn_mutex);



		wake_up(&isert_conn->conn_wait_comp_err);

		wake_up(&isert_conn->conn_wait_comp_err);

	}

	}

}

}
@@ -2209,6 +2231,17 @@ isert_free_np(struct iscsi_np *np) 
	kfree(isert_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_free_conn(struct iscsi_conn *conn)

{

{

	struct isert_conn *isert_conn = conn->context;

	struct isert_conn *isert_conn = conn->context;
@@ -2218,26 +2251,43 @@ static void isert_free_conn(struct iscsi_conn *conn) 
	 * Decrement post_send_buf_count for special case when called

	 * Decrement post_send_buf_count for special case when called

	 * from isert_do_control_comp() -> iscsit_logout_post_handler()

	 * from isert_do_control_comp() -> iscsit_logout_post_handler()

	 */

	 */

	mutex_lock(&isert_conn->conn_mutex);

	if (isert_conn->logout_posted)

	if (isert_conn->logout_posted)

		atomic_dec(&isert_conn->post_send_buf_count);

		atomic_dec(&isert_conn->post_send_buf_count);





	if (isert_conn->conn_cm_id)

	if (isert_conn->conn_cm_id && isert_conn->state != ISER_CONN_DOWN) {

		pr_debug("Calling rdma_disconnect from isert_free_conn\n");

		rdma_disconnect(isert_conn->conn_cm_id);

		rdma_disconnect(isert_conn->conn_cm_id);

	}

	/*

	/*

	 * Only wait for conn_wait_comp_err if the isert_conn made it

	 * Only wait for conn_wait_comp_err if the isert_conn made it

	 * into full feature phase..

	 * into full feature phase..

	 */

	 */

	if (isert_conn->state > ISER_CONN_INIT) {

	if (isert_conn->state == ISER_CONN_UP) {

		pr_debug("isert_free_conn: Before wait_event comp_err %d\n",

		pr_debug("isert_free_conn: Before wait_event comp_err %d\n",

			 isert_conn->state);

			 isert_conn->state);

		mutex_unlock(&isert_conn->conn_mutex);



		wait_event(isert_conn->conn_wait_comp_err,

		wait_event(isert_conn->conn_wait_comp_err,

			   isert_conn->state == ISER_CONN_TERMINATING);

			  (isert_check_state(isert_conn, ISER_CONN_TERMINATING)));

		pr_debug("isert_free_conn: After wait_event #1 >>>>>>>>>>>>\n");



		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);

	mutex_unlock(&isert_conn->conn_mutex);





	pr_debug("isert_free_conn: wait_event conn_wait %d\n", isert_conn->state);

	wait_event(isert_conn->conn_wait,

	wait_event(isert_conn->conn_wait, isert_conn->state == ISER_CONN_DOWN);

		  (isert_check_state(isert_conn, ISER_CONN_DOWN)));

	pr_debug("isert_free_conn: After wait_event #2 >>>>>>>>>>>>>>>>>>>>\n");





	isert_put_conn(isert_conn);

	isert_put_conn(isert_conn);

}

}

drivers/infiniband/ulp/isert/ib_isert.h

+1 −0
Original line number Original line Diff line number Diff line
@@ -102,6 +102,7 @@ struct isert_conn { 
	struct ib_qp		*conn_qp;

	struct ib_qp		*conn_qp;

	struct isert_device	*conn_device;

	struct isert_device	*conn_device;

	struct work_struct	conn_logout_work;

	struct work_struct	conn_logout_work;

	struct mutex		conn_mutex;

	wait_queue_head_t	conn_wait;

	wait_queue_head_t	conn_wait;

	wait_queue_head_t	conn_wait_comp_err;

	wait_queue_head_t	conn_wait_comp_err;

	struct kref		conn_kref;

	struct kref		conn_kref;

drivers/target/iscsi/iscsi_target_erl0.c

+1 −0
Original line number Original line Diff line number Diff line
@@ -908,6 +908,7 @@ void iscsit_cause_connection_reinstatement(struct iscsi_conn *conn, int sleep) 
	wait_for_completion(&conn->conn_wait_comp);

	wait_for_completion(&conn->conn_wait_comp);

	complete(&conn->conn_post_wait_comp);

	complete(&conn->conn_post_wait_comp);

}

}

EXPORT_SYMBOL(iscsit_cause_connection_reinstatement);





void iscsit_fall_back_to_erl0(struct iscsi_session *sess)

void iscsit_fall_back_to_erl0(struct iscsi_session *sess)

{

{

include/target/iscsi/iscsi_transport.h

+4 −0
Original line number Original line Diff line number Diff line
@@ -72,6 +72,10 @@ extern int iscsit_logout_post_handler(struct iscsi_cmd *, struct iscsi_conn *); 
 * From iscsi_target_device.c

 * From iscsi_target_device.c

 */

 */

extern void iscsit_increment_maxcmdsn(struct iscsi_cmd *, struct iscsi_session *);

extern void iscsit_increment_maxcmdsn(struct iscsi_cmd *, struct iscsi_session *);

/*

 * From iscsi_target_erl0.c

 */

extern void iscsit_cause_connection_reinstatement(struct iscsi_conn *, int);

/*

/*

 * From iscsi_target_erl1.c

 * From iscsi_target_erl1.c

 */

 */