CIFS: Add SMB2 credits support

For SMB2 protocol we can add more than one credit for one received
request: it depends on CreditRequest field in SMB2 response header.
Also we divide all requests by type: echoes, oplocks and others.
Each type uses its own slot pull.

Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Pavel Shilovsky <pshilovsky@samba.org>
Signed-off-by: Steve French <smfrench@gmail.com>
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index cfb7e77..a619722 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -297,7 +297,7 @@
  * reconnect tcp session
  * wake up waiters on reconnection? - (not needed currently)
  */
-static int
+int
 cifs_reconnect(struct TCP_Server_Info *server)
 {
 	int rc = 0;