nvmet-tcp: use 'spin_lock_bh' for state_lock()

nvmet_tcp_schedule_release_queue() is called from socket state
change callbacks, which may be called from an softirq context.
So use 'spin_lock_bh' to avoid a spin lock warning.
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>

drivers/nvme/target/tcp.c

@@ -1379,7 +1379,7 @@ static void nvmet_tcp_release_queue(struct kref *kref)
 
 static void nvmet_tcp_schedule_release_queue(struct nvmet_tcp_queue *queue)
 {
-	spin_lock(&queue->state_lock);
+	spin_lock_bh(&queue->state_lock);
 	if (queue->state == NVMET_TCP_Q_TLS_HANDSHAKE) {
 		/* Socket closed during handshake */
 		tls_handshake_cancel(queue->sock->sk);
@@ -1388,7 +1388,7 @@ static void nvmet_tcp_schedule_release_queue(struct nvmet_tcp_queue *queue)
 		queue->state = NVMET_TCP_Q_DISCONNECTING;
 		kref_put(&queue->kref, nvmet_tcp_release_queue);
 	}
-	spin_unlock(&queue->state_lock);
+	spin_unlock_bh(&queue->state_lock);
 }
 
 static inline void nvmet_tcp_arm_queue_deadline(struct nvmet_tcp_queue *queue)