SUNRPC move svc_drop to caller of svc_process_common

The NFSv4.1 shared back channel does not need to call svc_drop because the
callback service never outlives the single connection it services, and it
reuses it's buffers and keeps the trasport.
Signed-off-by: Andy Adamson <andros@netapp.com>
Acked-by: Bruce Fields <bfields@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

net/sunrpc/svc.c

@@ -1147,7 +1147,6 @@ svc_process_common(struct svc_rqst *rqstp, struct kvec *argv, struct kvec *resv)
  dropit:
 	svc_authorise(rqstp);	/* doesn't hurt to call this twice */
 	dprintk("svc: svc_process dropit\n");
-	svc_drop(rqstp);
 	return 0;
 
 err_short_len:
@@ -1218,7 +1217,6 @@ svc_process(struct svc_rqst *rqstp)
 	struct kvec		*resv = &rqstp->rq_res.head[0];
 	struct svc_serv		*serv = rqstp->rq_server;
 	u32			dir;
-	int			error;
 
 	/*
 	 * Setup response xdr_buf.
@@ -1246,11 +1244,13 @@ svc_process(struct svc_rqst *rqstp)
 		return 0;
 	}
 
-	error = svc_process_common(rqstp, argv, resv);
-	if (error <= 0)
-		return error;
-
-	return svc_send(rqstp);
+	/* Returns 1 for send, 0 for drop */
+	if (svc_process_common(rqstp, argv, resv))
+		return svc_send(rqstp);
+	else {
+		svc_drop(rqstp);
+		return 0;
+	}
 }
 
 #if defined(CONFIG_NFS_V4_1)
@@ -1264,7 +1264,6 @@ bc_svc_process(struct svc_serv *serv, struct rpc_rqst *req,
 {
 	struct kvec	*argv = &rqstp->rq_arg.head[0];
 	struct kvec	*resv = &rqstp->rq_res.head[0];
-	int 		error;
 
 	/* Build the svc_rqst used by the common processing routine */
 	rqstp->rq_xprt = serv->bc_xprt;
@@ -1292,12 +1291,15 @@ bc_svc_process(struct svc_serv *serv, struct rpc_rqst *req,
 	svc_getu32(argv);	/* XID */
 	svc_getnl(argv);	/* CALLDIR */
 
-	error = svc_process_common(rqstp, argv, resv);
-	if (error <= 0)
-		return error;
-
-	memcpy(&req->rq_snd_buf, &rqstp->rq_res, sizeof(req->rq_snd_buf));
-	return bc_send(req);
+	/* Returns 1 for send, 0 for drop */
+	if (svc_process_common(rqstp, argv, resv)) {
+		memcpy(&req->rq_snd_buf, &rqstp->rq_res,
+						sizeof(req->rq_snd_buf));
+		return bc_send(req);
+	} else {
+		/* Nothing to do to drop request */
+		return 0;
+	}
 }
 EXPORT_SYMBOL(bc_svc_process);
 #endif /* CONFIG_NFS_V4_1 */