scsi: target: iscsi: Avoid in_interrupt() usage in iscsit_close_session()

iscsit_close_session() uses in_interrupt() to decide if it needs to check
the return value of iscsit_check_session_usage_count() if it was not able
to sleep.

The usage of in_interrupt() in drivers is phased out and Linus clearly
requested that code which changes behaviour depending on context should
either be separated or the context be conveyed in an argument passed by the
caller, which usually knows the context.

iscsit_close_session() has two callers:

 - iscsit_handle_time2retain_timeout()
   A timer_list callback.

 - iscsit_close_connection()
   Runs in preemptible context, acquires a mutex.

Add an argument to iscsit_close_session() indicating if sleeping is
possible.

Link: https://lore.kernel.org/r/20201220203638.43615-2-bigeasy@linutronix.de
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/target/iscsi/iscsi_target.c

@@ -4327,7 +4327,7 @@ int iscsit_close_connection(
 	     atomic_read(&sess->session_fall_back_to_erl0)) {
 		spin_unlock_bh(&sess->conn_lock);
 		complete_all(&sess->session_wait_comp);
-		iscsit_close_session(sess);
+		iscsit_close_session(sess, true);
 
 		return 0;
 	} else if (atomic_read(&sess->session_logout)) {
@@ -4337,7 +4337,7 @@ int iscsit_close_connection(
 		if (atomic_read(&sess->session_close)) {
 			spin_unlock_bh(&sess->conn_lock);
 			complete_all(&sess->session_wait_comp);
-			iscsit_close_session(sess);
+			iscsit_close_session(sess, true);
 		} else {
 			spin_unlock_bh(&sess->conn_lock);
 		}
@@ -4353,7 +4353,7 @@ int iscsit_close_connection(
 		if (atomic_read(&sess->session_close)) {
 			spin_unlock_bh(&sess->conn_lock);
 			complete_all(&sess->session_wait_comp);
-			iscsit_close_session(sess);
+			iscsit_close_session(sess, true);
 		} else {
 			spin_unlock_bh(&sess->conn_lock);
 		}
@@ -4366,7 +4366,7 @@ int iscsit_close_connection(
  * If the iSCSI Session for the iSCSI Initiator Node exists,
  * forcefully shutdown the iSCSI NEXUS.
  */
-int iscsit_close_session(struct iscsi_session *sess)
+int iscsit_close_session(struct iscsi_session *sess, bool can_sleep)
 {
 	struct iscsi_portal_group *tpg = sess->tpg;
 	struct se_portal_group *se_tpg = &tpg->tpg_se_tpg;
@@ -4399,7 +4399,7 @@ int iscsit_close_session(struct iscsi_session *sess)
 	 * time2retain handler) and contain and active session usage count we
 	 * restart the timer and exit.
 	 */
-	if (!in_interrupt()) {
+	if (can_sleep) {
 		iscsit_check_session_usage_count(sess);
 	} else {
 		if (iscsit_check_session_usage_count(sess) == 2) {

drivers/target/iscsi/iscsi_target.h

@@ -41,7 +41,7 @@ extern void iscsit_thread_get_cpumask(struct iscsi_conn *);
 extern int iscsi_target_tx_thread(void *);
 extern int iscsi_target_rx_thread(void *);
 extern int iscsit_close_connection(struct iscsi_conn *);
-extern int iscsit_close_session(struct iscsi_session *);
+extern int iscsit_close_session(struct iscsi_session *, bool can_sleep);
 extern void iscsit_fail_session(struct iscsi_session *);
 extern void iscsit_stop_session(struct iscsi_session *, int, int);
 extern int iscsit_release_sessions_for_tpg(struct iscsi_portal_group *, int);

drivers/target/iscsi/iscsi_target_erl0.c

@@ -765,7 +765,7 @@ void iscsit_handle_time2retain_timeout(struct timer_list *t)
 
 	iscsit_fill_cxn_timeout_err_stats(sess);
 	spin_unlock_bh(&se_tpg->session_lock);
-	iscsit_close_session(sess);
+	iscsit_close_session(sess, false);
 }
 
 void iscsit_start_time2retain_handler(struct iscsi_session *sess)