From 197b806ae5db60c6f609d74da04ddb62ea5e1b00 Mon Sep 17 00:00:00 2001 From: Nicholas Bellinger Date: Tue, 25 Apr 2017 10:55:12 -0700 Subject: iscsi-target: Set session_fall_back_to_erl0 when forcing reinstatement While testing modification of per se_node_acl queue_depth forcing session reinstatement via lio_target_nacl_cmdsn_depth_store() -> core_tpg_set_initiator_node_queue_depth(), a hung task bug triggered when changing cmdsn_depth invoked session reinstatement while an iscsi login was already waiting for session reinstatement to complete. This can happen when an outstanding se_cmd descriptor is taking a long time to complete, and session reinstatement from iscsi login or cmdsn_depth change occurs concurrently. To address this bug, explicitly set session_fall_back_to_erl0 = 1 when forcing session reinstatement, so session reinstatement is not attempted if an active session is already being shutdown. This patch has been tested with two scenarios. The first when iscsi login is blocked waiting for iscsi session reinstatement to complete followed by queue_depth change via configfs, and second when queue_depth change via configfs us blocked followed by a iscsi login driven session reinstatement. Note this patch depends on commit d36ad77f702 to handle multiple sessions per se_node_acl when changing cmdsn_depth, and for pre v4.5 kernels will need to be included for stable as well. Reported-by: Gary Guo Tested-by: Gary Guo Cc: Gary Guo Cc: # v4.1+ Signed-off-by: Nicholas Bellinger --- drivers/target/iscsi/iscsi_target.c | 1 + drivers/target/iscsi/iscsi_target_configfs.c | 1 + drivers/target/iscsi/iscsi_target_login.c | 1 + 3 files changed, 3 insertions(+) (limited to 'drivers/target') diff --git a/drivers/target/iscsi/iscsi_target.c b/drivers/target/iscsi/iscsi_target.c index 0f7ade04b583..26a9bcd5ee6a 100644 --- a/drivers/target/iscsi/iscsi_target.c +++ b/drivers/target/iscsi/iscsi_target.c @@ -4663,6 +4663,7 @@ int iscsit_release_sessions_for_tpg(struct iscsi_portal_group *tpg, int force) continue; } atomic_set(&sess->session_reinstatement, 1); + atomic_set(&sess->session_fall_back_to_erl0, 1); spin_unlock(&sess->conn_lock); list_move_tail(&se_sess->sess_list, &free_list); diff --git a/drivers/target/iscsi/iscsi_target_configfs.c b/drivers/target/iscsi/iscsi_target_configfs.c index 344e8448869c..96d9c73af1ae 100644 --- a/drivers/target/iscsi/iscsi_target_configfs.c +++ b/drivers/target/iscsi/iscsi_target_configfs.c @@ -1528,6 +1528,7 @@ static void lio_tpg_close_session(struct se_session *se_sess) return; } atomic_set(&sess->session_reinstatement, 1); + atomic_set(&sess->session_fall_back_to_erl0, 1); spin_unlock(&sess->conn_lock); iscsit_stop_time2retain_timer(sess); diff --git a/drivers/target/iscsi/iscsi_target_login.c b/drivers/target/iscsi/iscsi_target_login.c index ad8f3011bdc2..66238477137b 100644 --- a/drivers/target/iscsi/iscsi_target_login.c +++ b/drivers/target/iscsi/iscsi_target_login.c @@ -208,6 +208,7 @@ int iscsi_check_for_session_reinstatement(struct iscsi_conn *conn) initiatorname_param->value) && (sess_p->sess_ops->SessionType == sessiontype))) { atomic_set(&sess_p->session_reinstatement, 1); + atomic_set(&sess_p->session_fall_back_to_erl0, 1); spin_unlock(&sess_p->conn_lock); iscsit_inc_session_usage_count(sess_p); iscsit_stop_time2retain_timer(sess_p); -- cgit