[PATCH 2/5] target: Add se_node_acl->acl_free_comp for NodeACL release path

["Nicholas A. Bellinger" <nab@xxxxxxxxxxxxxxx>]

From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>

Convert core_tpg_del_initiator_node_acl() to use target_put_session() kref
counting, and add se_node_acl->acl_free_comp to wait for outstanding fabric
session shutdown to complete in transport_deregister_session() before
finishing configfs NodeACL release.

Cc: Roland Dreier <roland@xxxxxxxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Andy Grover <agrover@xxxxxxxxxx>
Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
---
 drivers/target/target_core_tpg.c       |   23 ++++++++++++-----------
 drivers/target/target_core_transport.c |    6 ++++++
 include/target/target_core_base.h      |    1 +
 3 files changed, 19 insertions(+), 11 deletions(-)

diff --git a/drivers/target/target_core_tpg.c b/drivers/target/target_core_tpg.c
index 3215340..a3ece61 100644
--- a/drivers/target/target_core_tpg.c
+++ b/drivers/target/target_core_tpg.c
@@ -274,6 +274,7 @@ struct se_node_acl *core_tpg_check_initiator_node_acl(
 
 	INIT_LIST_HEAD(&acl->acl_list);
 	INIT_LIST_HEAD(&acl->acl_sess_list);
+	init_completion(&acl->acl_free_comp);
 	spin_lock_init(&acl->device_list_lock);
 	spin_lock_init(&acl->nacl_sess_lock);
 	atomic_set(&acl->acl_pr_ref_count, 0);
@@ -402,6 +403,7 @@ struct se_node_acl *core_tpg_add_initiator_node_acl(
 
 	INIT_LIST_HEAD(&acl->acl_list);
 	INIT_LIST_HEAD(&acl->acl_sess_list);
+	init_completion(&acl->acl_free_comp);
 	spin_lock_init(&acl->device_list_lock);
 	spin_lock_init(&acl->nacl_sess_lock);
 	atomic_set(&acl->acl_pr_ref_count, 0);
@@ -450,7 +452,7 @@ int core_tpg_del_initiator_node_acl(
 {
 	struct se_session *sess, *sess_tmp;
 	unsigned long flags;
-	int dynamic_acl = 0;
+	int dynamic_acl = 0, rc;
 
 	spin_lock_irq(&tpg->acl_node_lock);
 	if (acl->dynamic_node_acl) {
@@ -466,18 +468,17 @@ int core_tpg_del_initiator_node_acl(
 				&tpg->tpg_sess_list, sess_list) {
 		if (sess->se_node_acl != acl)
 			continue;
-		/*
-		 * Determine if the session needs to be closed by our context.
-		 */
-		if (!tpg->se_tpg_tfo->shutdown_session(sess))
-			continue;
 
+		kref_get(&sess->sess_kref);
 		spin_unlock_irqrestore(&tpg->session_lock, flags);
-		/*
-		 * If the $FABRIC_MOD session for the Initiator Node ACL exists,
-		 * forcefully shutdown the $FABRIC_MOD session/nexus.
-		 */
-		tpg->se_tpg_tfo->close_session(sess);
+
+		rc = tpg->se_tpg_tfo->shutdown_session(sess);
+		target_put_session(sess);
+		if (!rc)
+			continue;
+		target_put_session(sess);
+		/* Wait for fabric session shutdown to complete.. */
+		wait_for_completion(&acl->acl_free_comp);
 
 		spin_lock_irqsave(&tpg->session_lock, flags);
 	}
diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index 751c527..ce36360 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -414,6 +414,12 @@ void transport_deregister_session(struct se_session *se_sess)
 
 	pr_debug("TARGET_CORE[%s]: Deregistered fabric_sess\n",
 		se_tpg->se_tpg_tfo->get_fabric_name());
+	/*
+	 * Awake sleeping ->acl_free_comp caller from configfs se_node_acl
+	 * removal context
+	 */
+	if (comp_nacl)
+		complete(&se_nacl->acl_free_comp);
 }
 EXPORT_SYMBOL(transport_deregister_session);
 
diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h
index 6470901..9bb1c0f 100644
--- a/include/target/target_core_base.h
+++ b/include/target/target_core_base.h
@@ -642,6 +642,7 @@ struct se_node_acl {
 	struct config_group	*acl_default_groups[5];
 	struct list_head	acl_list;
 	struct list_head	acl_sess_list;
+	struct completion	acl_free_comp;
 };
 
 struct se_session {
-- 
1.7.2.5

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