cifs: don't return error from standard_receive3 after marking response malformed

standard_receive3 will check the validity of the response from the
server (via checkSMB). It'll pass the result of that check to handle_mid
which will dequeue it and mark it with a status of
MID_RESPONSE_MALFORMED if checkSMB returned an error. At that point,
standard_receive3 will also return an error, which will make the
demultiplex thread skip doing the callback for the mid.

This is wrong -- if we were able to identify the request and the
response is marked malformed, then we want the demultiplex thread to do
the callback. Fix this by making standard_receive3 return 0 in this
situation.

Cc: stable@vger.kernel.org
Reported-and-Tested-by: Mark Moseley <moseleymark@gmail.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>

fs/cifs/connect.c

@@ -773,10 +773,11 @@ standard_receive3(struct TCP_Server_Info *server, struct mid_q_entry *mid)
 		cifs_dump_mem("Bad SMB: ", buf,
 			min_t(unsigned int, server->total_read, 48));
 
-	if (mid)
-		handle_mid(mid, server, smb_buffer, length);
+	if (!mid)
+		return length;
 
-	return length;
+	handle_mid(mid, server, smb_buffer, length);
+	return 0;
 }
 
 static int