target: Convert ACL change queue_depth se_session reference usage

This patch converts core_tpg_set_initiator_node_queue_depth()
to use struct se_node_acl->acl_sess_list when performing
explicit se_tpg_tfo->shutdown_session() for active sessions,
in order for new se_node_acl->queue_depth to take effect.

This follows how core_tpg_del_initiator_node_acl() currently
works when invoking se_tpg_tfo->shutdown-session(), and ahead
of the next patch to take se_node_acl->acl_kref during lookup,
the extra get_initiator_node_acl() can go away. In order to
achieve this, go ahead and change target_get_session() to use
kref_get_unless_zero() and propigate up the return value
to know when a session is already being released.

This is because se_node_acl->acl_group is already protecting
se_node_acl->acl_group reference via configfs, and shutdown
within core_tpg_del_initiator_node_acl() won't occur until
sys_write() to core_tpg_set_initiator_node_queue_depth()
attribute returns back to user-space.

Also, drop the left-over iscsi-target hack, and obtain
se_portal_group->session_lock in lio_tpg_shutdown_session()
internally. Remove iscsi-target wrapper and unused se_tpg +
force parameters and associated code.

Reported-by: Christoph Hellwig <hch@lst.de>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Andy Grover <agrover@redhat.com>
Cc: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

1 files changed, 7 insertions, 22 deletions

diff --git a/drivers/target/iscsi/iscsi_target_configfs.c b/drivers/target/iscsi/iscsi_target_configfs.c
index b4bfd706ac94..2f821de63049 100644
--- a/drivers/target/iscsi/iscsi_target_configfs.c
+++ b/drivers/target/iscsi/iscsi_target_configfs.c
@@ -725,11 +725,8 @@ static ssize_t lio_target_nacl_cmdsn_depth_store(struct config_item *item,
 
 	if (iscsit_get_tpg(tpg) < 0)
 		return -EINVAL;
-	/*
-	 * iscsit_tpg_set_initiator_node_queue_depth() assumes force=1
-	 */
-	ret = iscsit_tpg_set_initiator_node_queue_depth(tpg,
-				config_item_name(acl_ci), cmdsn_depth, 1);
+
+	ret = core_tpg_set_initiator_node_queue_depth(se_nacl, cmdsn_depth);
 
 	pr_debug("LIO_Target_ConfigFS: %s/%s Set CmdSN Window: %u for"
 		"InitiatorName: %s\n", config_item_name(wwn_ci),
@@ -1593,42 +1590,30 @@ static int lio_tpg_check_prot_fabric_only(
 }
 
 /*
- * Called with spin_lock_irq(struct se_portal_group->session_lock) held
- * or not held.
- *
- * Also, this function calls iscsit_inc_session_usage_count() on the
+ * This function calls iscsit_inc_session_usage_count() on the
  * struct iscsi_session in question.
  */
 static int lio_tpg_shutdown_session(struct se_session *se_sess)
 {
 	struct iscsi_session *sess = se_sess->fabric_sess_ptr;
-	struct se_portal_group *se_tpg = se_sess->se_tpg;
-	bool local_lock = false;
-
-	if (!spin_is_locked(&se_tpg->session_lock)) {
-		spin_lock_irq(&se_tpg->session_lock);
-		local_lock = true;
-	}
+	struct se_portal_group *se_tpg = &sess->tpg->tpg_se_tpg;
 
+	spin_lock_bh(&se_tpg->session_lock);
 	spin_lock(&sess->conn_lock);
 	if (atomic_read(&sess->session_fall_back_to_erl0) ||
 	    atomic_read(&sess->session_logout) ||
 	    (sess->time2retain_timer_flags & ISCSI_TF_EXPIRED)) {
 		spin_unlock(&sess->conn_lock);
-		if (local_lock)
-			spin_unlock_irq(&sess->conn_lock);
+		spin_unlock_bh(&se_tpg->session_lock);
 		return 0;
 	}
 	atomic_set(&sess->session_reinstatement, 1);
 	spin_unlock(&sess->conn_lock);
 
 	iscsit_stop_time2retain_timer(sess);
-	spin_unlock_irq(&se_tpg->session_lock);
+	spin_unlock_bh(&se_tpg->session_lock);
 
 	iscsit_stop_session(sess, 1, 1);
-	if (!local_lock)
-		spin_lock_irq(&se_tpg->session_lock);
-
 	return 1;
 }