cifs: Make add_credits_and_wake_if() clear deducted credits

Make add_credits_and_wake_if() clear the amount of credits in the
cifs_credits struct after it has returned them to the overall counter.
This allows add_credits_and_wake_if() to be called multiple times during
the error handling and cleanup without accidentally returning the credits
again and again.

Note that the wake_up() in add_credits_and_wake_if() may also be
superfluous as ->add_credits() also does a wake on the request_q.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Steve French <sfrench@samba.org>
cc: Shyam Prasad N <nspmangalore@gmail.com>
cc: Rohith Surabattula <rohiths.msft@gmail.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: linux-cifs@vger.kernel.org
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org

Author: dhowells

fs/smb/client/cifsglob.h

@@ -881,11 +881,12 @@ add_credits(struct TCP_Server_Info *server, const struct cifs_credits *credits,
 
 static inline void
 add_credits_and_wake_if(struct TCP_Server_Info *server,
-			const struct cifs_credits *credits, const int optype)
+			struct cifs_credits *credits, const int optype)
 {
 	if (credits->value) {
 		server->ops->add_credits(server, credits, optype);
 		wake_up(&server->request_q);
+		credits->value = 0;
 	}
 }