CIFS: Do not set credits to 1 if the server didn't grant anything

commit 33fa5c8b8a7dbe6353a56eaa654b790348890d42 upstream.

Currently we reset the number of total credits granted by the server
to 1 if the server didn't grant us anything int the response. This
violates the SMB3 protocol - we need to trust the server and use
the credit values from the response. Fix this by removing the
corresponding code.
Signed-off-by: NPavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>
CC: Stable <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

fs/cifs/transport.c

@@ -885,8 +885,6 @@ compound_send_recv(const unsigned int xid, struct cifs_ses *ses,
 	for (i = 0; i < num_rqst; i++)
 		if (midQ[i]->resp_buf)
 			credits += ses->server->ops->get_credits(midQ[i]);
-	if (!credits)
-		credits = 1;
 
 	for (i = 0; i < num_rqst; i++) {
 		if (rc < 0)