iser-target: Fix session reset bug with RDMA_CM_EVENT_DISCONNECTED

commit b2cb96494d83b894a43ba8b9023eead8ff50684b upstream.

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: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/include/target/iscsi/iscsi_transport.h b/include/target/iscsi/iscsi_transport.h
index 23a87d0cd72c..6db632eb3821 100644
--- a/include/target/iscsi/iscsi_transport.h
+++ b/include/target/iscsi/iscsi_transport.h
@@ -67,6 +67,10 @@ extern int iscsit_logout_post_handler(struct iscsi_cmd *, struct iscsi_conn *);
  */
 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
  */
 extern void iscsit_stop_dataout_timer(struct iscsi_cmd *);