From bc6e6bb470eda42f44bcac96c261cff1216577b3 Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@lst.de>
Date: Mon, 2 May 2016 15:45:19 +0200
Subject: [PATCH] target: consolidate and fix session shutdown

Factor out a helper to shutdown sessions for a Node ACL, and make it
properly restart the list walk after dropping the lock.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
---
 drivers/target/target_core_tpg.c | 91 ++++++++++++--------------------
 1 file changed, 35 insertions(+), 56 deletions(-)

diff --git a/drivers/target/target_core_tpg.c b/drivers/target/target_core_tpg.c
index ddf046080dc3..88db4938600b 100644
--- a/drivers/target/target_core_tpg.c
+++ b/drivers/target/target_core_tpg.c
@@ -336,44 +336,47 @@ struct se_node_acl *core_tpg_add_initiator_node_acl(
 	return acl;
 }
 
+static void target_shutdown_sessions(struct se_node_acl *acl, bool acl_stop)
+{
+	struct se_session *sess;
+	unsigned long flags;
+	int ret;
+
+	spin_lock_irqsave(&acl->nacl_sess_lock, flags);
+	if (acl_stop)
+		acl->acl_stop = 1;
+restart:
+	list_for_each_entry(sess, &acl->acl_sess_list, sess_acl_list) {
+		if (sess->sess_tearing_down)
+			continue;
+		if (!target_get_session(sess))
+			continue;
+
+		list_del(&sess->sess_acl_list);
+
+		spin_unlock_irqrestore(&acl->nacl_sess_lock, flags);
+		ret = acl->se_tpg->se_tpg_tfo->shutdown_session(sess);
+		target_put_session(sess);
+		if (ret)
+			target_put_session(sess);
+		spin_lock_irqsave(&acl->nacl_sess_lock, flags);
+		goto restart;
+	}
+	spin_unlock_irqrestore(&acl->nacl_sess_lock, flags);
+}
+
 void core_tpg_del_initiator_node_acl(struct se_node_acl *acl)
 {
 	struct se_portal_group *tpg = acl->se_tpg;
-	LIST_HEAD(sess_list);
-	struct se_session *sess, *sess_tmp;
-	unsigned long flags;
-	int rc;
 
 	mutex_lock(&tpg->acl_node_mutex);
-	if (acl->dynamic_node_acl) {
+	if (acl->dynamic_node_acl)
 		acl->dynamic_node_acl = 0;
-	}
 	list_del(&acl->acl_list);
 	mutex_unlock(&tpg->acl_node_mutex);
 
-	spin_lock_irqsave(&acl->nacl_sess_lock, flags);
-	acl->acl_stop = 1;
+	target_shutdown_sessions(acl, true);
 
-	list_for_each_entry_safe(sess, sess_tmp, &acl->acl_sess_list,
-				sess_acl_list) {
-		if (sess->sess_tearing_down != 0)
-			continue;
-
-		if (!target_get_session(sess))
-			continue;
-		list_move(&sess->sess_acl_list, &sess_list);
-	}
-	spin_unlock_irqrestore(&acl->nacl_sess_lock, flags);
-
-	list_for_each_entry_safe(sess, sess_tmp, &sess_list, sess_acl_list) {
-		list_del(&sess->sess_acl_list);
-
-		rc = tpg->se_tpg_tfo->shutdown_session(sess);
-		target_put_session(sess);
-		if (!rc)
-			continue;
-		target_put_session(sess);
-	}
 	target_put_nacl(acl);
 	/*
 	 * Wait for last target_put_nacl() to complete in target_complete_nacl()
@@ -400,11 +403,7 @@ int core_tpg_set_initiator_node_queue_depth(
 	struct se_node_acl *acl,
 	u32 queue_depth)
 {
-	LIST_HEAD(sess_list);
 	struct se_portal_group *tpg = acl->se_tpg;
-	struct se_session *sess, *sess_tmp;
-	unsigned long flags;
-	int rc;
 
 	/*
 	 * User has requested to change the queue depth for a Initiator Node.
@@ -413,30 +412,10 @@ int core_tpg_set_initiator_node_queue_depth(
 	 */
 	target_set_nacl_queue_depth(tpg, acl, queue_depth);
 
-	spin_lock_irqsave(&acl->nacl_sess_lock, flags);
-	list_for_each_entry_safe(sess, sess_tmp, &acl->acl_sess_list,
-				 sess_acl_list) {
-		if (sess->sess_tearing_down != 0)
-			continue;
-		if (!target_get_session(sess))
-			continue;
-		spin_unlock_irqrestore(&acl->nacl_sess_lock, flags);
-
-		/*
-		 * Finally call tpg->se_tpg_tfo->close_session() to force session
-		 * reinstatement to occur if there is an active session for the
-		 * $FABRIC_MOD Initiator Node in question.
-		 */
-		rc = tpg->se_tpg_tfo->shutdown_session(sess);
-		target_put_session(sess);
-		if (!rc) {
-			spin_lock_irqsave(&acl->nacl_sess_lock, flags);
-			continue;
-		}
-		target_put_session(sess);
-		spin_lock_irqsave(&acl->nacl_sess_lock, flags);
-	}
-	spin_unlock_irqrestore(&acl->nacl_sess_lock, flags);
+	/*
+	 * Shutdown all pending sessions to force session reinstatement.
+	 */
+	target_shutdown_sessions(acl, false);
 
 	pr_debug("Successfully changed queue depth to: %d for Initiator"
 		" Node: %s on %s Target Portal Group: %u\n", acl->queue_depth,