scsi: target: iscsi: Redo iscsit_check_session_usage_count() return code

The return value of iscsit_check_session_usage_count() is only checked if
it was not allowed to sleep. If it returns `2' then a timer is prepared. If
it returns something else or if it was allowed to sleep then it is ignored.

Let iscsit_check_session_usage_count() return true if it needs to arm the
timer - otherwise false. This simplifies the code flow of the only caller.

Link: https://lore.kernel.org/r/20201220203638.43615-4-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

@@ -4399,14 +4399,10 @@ int iscsit_close_session(struct iscsi_session *sess, bool can_sleep)
 	 * time2retain handler) and contain and active session usage count we
 	 * restart the timer and exit.
 	 */
-	if (can_sleep) {
-		iscsit_check_session_usage_count(sess, can_sleep);
-	} else {
-		if (iscsit_check_session_usage_count(sess, can_sleep) == 2) {
-			atomic_set(&sess->session_logout, 0);
-			iscsit_start_time2retain_handler(sess);
-			return 0;
-		}
+	if (iscsit_check_session_usage_count(sess, can_sleep)) {
+		atomic_set(&sess->session_logout, 0);
+		iscsit_start_time2retain_handler(sess);
+		return 0;
 	}
 
 	transport_deregister_session(sess->se_sess);

drivers/target/iscsi/iscsi_target_util.c

@@ -779,21 +779,22 @@ void iscsit_free_cmd(struct iscsi_cmd *cmd, bool shutdown)
 }
 EXPORT_SYMBOL(iscsit_free_cmd);
 
-int iscsit_check_session_usage_count(struct iscsi_session *sess, bool can_sleep)
+bool iscsit_check_session_usage_count(struct iscsi_session *sess,
+				      bool can_sleep)
 {
 	spin_lock_bh(&sess->session_usage_lock);
 	if (sess->session_usage_count != 0) {
 		sess->session_waiting_on_uc = 1;
 		spin_unlock_bh(&sess->session_usage_lock);
 		if (!can_sleep)
-			return 2;
+			return true;
 
 		wait_for_completion(&sess->session_waiting_on_uc_comp);
-		return 1;
+		return false;
 	}
 	spin_unlock_bh(&sess->session_usage_lock);
 
-	return 0;
+	return false;
 }
 
 void iscsit_dec_session_usage_count(struct iscsi_session *sess)

drivers/target/iscsi/iscsi_target_util.h

@@ -40,7 +40,7 @@ extern void iscsit_free_queue_reqs_for_conn(struct iscsi_conn *);
 extern void iscsit_release_cmd(struct iscsi_cmd *);
 extern void __iscsit_free_cmd(struct iscsi_cmd *, bool);
 extern void iscsit_free_cmd(struct iscsi_cmd *, bool);
-extern int iscsit_check_session_usage_count(struct iscsi_session *sess, bool can_sleep);
+extern bool iscsit_check_session_usage_count(struct iscsi_session *sess, bool can_sleep);
 extern void iscsit_dec_session_usage_count(struct iscsi_session *);
 extern void iscsit_inc_session_usage_count(struct iscsi_session *);
 extern struct iscsi_conn *iscsit_get_conn_from_cid(struct iscsi_session *, u16);