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authorNicholas Bellinger <nab@linux-iscsi.org>2017-04-25 10:55:12 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-05-20 14:28:34 +0200
commitbb1f06f53bcb111d8f2d5d58f9ae68c4a9cef81e (patch)
tree5a9b119146d295c15fdf05b46621cf8892add0d4 /drivers/target
parentf788fa43d87a4a2575deafb54e5333b06d34399d (diff)
iscsi-target: Set session_fall_back_to_erl0 when forcing reinstatement
commit 197b806ae5db60c6f609d74da04ddb62ea5e1b00 upstream. 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 <ghg@datera.io> Tested-by: Gary Guo <ghg@datera.io> Cc: Gary Guo <ghg@datera.io> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/target')
-rw-r--r--drivers/target/iscsi/iscsi_target.c1
-rw-r--r--drivers/target/iscsi/iscsi_target_configfs.c1
-rw-r--r--drivers/target/iscsi/iscsi_target_login.c1
3 files changed, 3 insertions, 0 deletions
diff --git a/drivers/target/iscsi/iscsi_target.c b/drivers/target/iscsi/iscsi_target.c
index b7d747e92c7a..40e50f2d209d 100644
--- a/drivers/target/iscsi/iscsi_target.c
+++ b/drivers/target/iscsi/iscsi_target.c
@@ -4671,6 +4671,7 @@ 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 e980e2d0c2db..7e70fe849f0d 100644
--- a/drivers/target/iscsi/iscsi_target_configfs.c
+++ b/drivers/target/iscsi/iscsi_target_configfs.c
@@ -1530,6 +1530,7 @@ 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 15f79a2ca34a..96c55bc10ac9 100644
--- a/drivers/target/iscsi/iscsi_target_login.c
+++ b/drivers/target/iscsi/iscsi_target_login.c
@@ -204,6 +204,7 @@ 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);