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Target/iser: Fix hangs in connection teardown

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In ungraceful teardowns isert close flows seem racy such that
isert_wait_conn hangs as RDMA_CM_EVENT_DISCONNECTED never
gets invoked (no one called rdma_disconnect).

Both graceful and ungraceful teardowns will have rx flush errors
(isert posts a batch once connection is established). Once all
flush errors are consumed we invoke isert_wait_conn and it will
be responsible for calling rdma_disconnect. This way it can be
sure that rdma_disconnect was called and it won't wait forever.

This patch also removes the logout_posted indicator. either the
logout completion was consumed and no problem decrementing the
post_send_buf_count, or it was consumed as a flush error. no point
of keeping it for isert_wait_conn as there is no danger that
isert_conn will be accidentally removed while it is running.

(Drop unnecessary sleep_on_conn_wait_comp check in
 isert_cq_rx_comp_err - nab)

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Cc: stable@vger.kernel.org # 3.10+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
This commit is contained in:
Sagi Grimberg 2014-05-19 17:44:23 +03:00 committed by Nicholas Bellinger
parent e346ab343f
commit 9d49f5e284
2 changed files with 10 additions and 22 deletions
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31
drivers/infiniband/ulp/isert/ib_isert.c
View file

@ -787,14 +787,10 @@ isert_disconnect_work(struct work_struct *work)
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;
}
/* Send DREQ/DREP towards our initiator */
rdma_disconnect(isert_conn->conn_cm_id);
mutex_unlock(&isert_conn->conn_mutex);
wake_up:
@ -1822,11 +1818,8 @@ isert_do_control_comp(struct work_struct *work)
break;
case ISTATE_SEND_LOGOUTRSP:
pr_debug("Calling iscsit_logout_post_handler >>>>>>>>>>>>>>\n");
/*
* Call atomic_dec(&isert_conn->post_send_buf_count)
* from isert_wait_conn()
*/
isert_conn->logout_posted = true;
atomic_dec(&isert_conn->post_send_buf_count);
iscsit_logout_post_handler(cmd, cmd->conn);
break;
case ISTATE_SEND_TEXTRSP:
@ -2032,6 +2025,8 @@ isert_cq_rx_comp_err(struct isert_conn *isert_conn)
isert_conn->state = ISER_CONN_DOWN;
mutex_unlock(&isert_conn->conn_mutex);
iscsit_cause_connection_reinstatement(isert_conn->conn, 0);
complete(&isert_conn->conn_wait_comp_err);
}
@ -3211,15 +3206,9 @@ static void isert_wait_conn(struct iscsi_conn *conn)
struct isert_conn *isert_conn = conn->context;
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()
*/
mutex_lock(&isert_conn->conn_mutex);
if (isert_conn->logout_posted)
atomic_dec(&isert_conn->post_send_buf_count);
if (isert_conn->conn_cm_id && isert_conn->state != ISER_CONN_DOWN) {
mutex_lock(&isert_conn->conn_mutex);
if (isert_conn->conn_cm_id) {
pr_debug("Calling rdma_disconnect from isert_wait_conn\n");
rdma_disconnect(isert_conn->conn_cm_id);
}

1
drivers/infiniband/ulp/isert/ib_isert.h
View file

@ -116,7 +116,6 @@ struct isert_device;
struct isert_conn {
enum iser_conn_state state;
bool logout_posted;
int post_recv_buf_count;
atomic_t post_send_buf_count;
u32 responder_resources;