cifs: smbd: Indicate to retry on transport sending failure

Failure to send a packet doesn't mean it's a permanent failure, it can't be
returned to user process. This I/O should be retried or failed based on
server packet response and transport health. This logic is handled by the
upper layer.

Give this decision to upper layer.
Signed-off-by: Long Li <longli@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/cifs/smbdirect.c

@@ -853,7 +853,7 @@ static int smbd_create_header(struct smbd_connection *info,
 
 	if (info->transport_status != SMBD_CONNECTED) {
 		log_outgoing(ERR, "disconnected not sending\n");
-		return -ENOENT;
+		return -EAGAIN;
 	}
 	atomic_dec(&info->send_credits);
 
@@ -979,6 +979,7 @@ static int smbd_post_send(struct smbd_connection *info,
 				wake_up(&info->wait_send_pending);
 		}
 		smbd_disconnect_rdma_connection(info);
+		rc = -EAGAIN;
 	} else
 		/* Reset timer for idle connection after packet is sent */
 		mod_delayed_work(info->workqueue, &info->idle_timer_work,
@@ -2085,7 +2086,7 @@ int smbd_send(struct TCP_Server_Info *server, struct smb_rqst *rqst)
 	int rc;
 
 	if (info->transport_status != SMBD_CONNECTED) {
-		rc = -ENODEV;
+		rc = -EAGAIN;
 		goto done;
 	}