cifs: change cifs_call_async to use smb_rqst structs

For now, none of the callers populate rq_pages. That will be done for
writes in a later patch. While we're at it, change the prototype of
setup_async_request not to need a return pointer argument. Just
return the pointer to the mid_q_entry or an ERR_PTR.

Reviewed-by: Pavel Shilovsky <pshilovsky@samba.org>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 5ea50dd..a817900 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -201,11 +201,11 @@
 			   struct mid_q_entry *);
 	bool (*compare_fids)(struct cifsFileInfo *, struct cifsFileInfo *);
 	/* setup request: allocate mid, sign message */
-	int (*setup_request)(struct cifs_ses *, struct kvec *, unsigned int,
-			     struct mid_q_entry **);
+	struct mid_q_entry *(*setup_request)(struct cifs_ses *,
+						struct smb_rqst *);
 	/* setup async request: allocate mid, sign message */
-	int (*setup_async_request)(struct TCP_Server_Info *, struct kvec *,
-				   unsigned int, struct mid_q_entry **);
+	struct mid_q_entry *(*setup_async_request)(struct TCP_Server_Info *,
+						struct smb_rqst *);
 	/* check response: verify signature, map error */
 	int (*check_receive)(struct mid_q_entry *, struct TCP_Server_Info *,
 			     bool);