NFS: Avoid return code checking in mount XDR encoder functions

Clean up.

The trend in the other XDR encoder functions is to BUG() when encoding
problems occur, since a problem here is always due to a local coding
error.  Then, instead of a status, zero is unconditionally returned.

Update the mount client XDR encoders to behave this way.

To finish the update, use the new-style be32_to_cpup() and
cpu_to_be32() macros, and compute the buffer sizes using raw integers
instead of sizeof().  This matches the conventions used in other XDR
functions.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Tested-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/mount_clnt.c

@@ -280,20 +280,14 @@ void nfs_umount(const struct nfs_mount_request *info)
  * XDR encode/decode functions for MOUNT
  */
 
-static int encode_mntdirpath(struct xdr_stream *xdr, const char *pathname)
+static void encode_mntdirpath(struct xdr_stream *xdr, const char *pathname)
 {
 	const u32 pathname_len = strlen(pathname);
 	__be32 *p;
 
-	if (unlikely(pathname_len > MNTPATHLEN))
-		return -EIO;
-
-	p = xdr_reserve_space(xdr, sizeof(u32) + pathname_len);
-	if (unlikely(p == NULL))
-		return -EIO;
+	BUG_ON(pathname_len > MNTPATHLEN);
+	p = xdr_reserve_space(xdr, 4 + pathname_len);
 	xdr_encode_opaque(p, pathname, pathname_len);
-
-	return 0;
 }
 
 static int mnt_enc_dirpath(struct rpc_rqst *req, __be32 *p,
@@ -302,7 +296,8 @@ static int mnt_enc_dirpath(struct rpc_rqst *req, __be32 *p,
 	struct xdr_stream xdr;
 
 	xdr_init_encode(&xdr, &req->rq_snd_buf, p);
-	return encode_mntdirpath(&xdr, dirpath);
+	encode_mntdirpath(&xdr, dirpath);
+	return 0;
 }
 
 /*
@@ -320,10 +315,10 @@ static int decode_status(struct xdr_stream *xdr, struct mountres *res)
 	u32 status;
 	__be32 *p;
 
-	p = xdr_inline_decode(xdr, sizeof(status));
+	p = xdr_inline_decode(xdr, 4);
 	if (unlikely(p == NULL))
 		return -EIO;
-	status = ntohl(*p);
+	status = be32_to_cpup(p);
 
 	for (i = 0; i < ARRAY_SIZE(mnt_errtbl); i++) {
 		if (mnt_errtbl[i].status == status) {
@@ -371,10 +366,10 @@ static int decode_fhs_status(struct xdr_stream *xdr, struct mountres *res)
 	u32 status;
 	__be32 *p;
 
-	p = xdr_inline_decode(xdr, sizeof(status));
+	p = xdr_inline_decode(xdr, 4);
 	if (unlikely(p == NULL))
 		return -EIO;
-	status = ntohl(*p);
+	status = be32_to_cpup(p);
 
 	for (i = 0; i < ARRAY_SIZE(mnt3_errtbl); i++) {
 		if (mnt3_errtbl[i].status == status) {
@@ -394,11 +389,11 @@ static int decode_fhandle3(struct xdr_stream *xdr, struct mountres *res)
 	u32 size;
 	__be32 *p;
 
-	p = xdr_inline_decode(xdr, sizeof(size));
+	p = xdr_inline_decode(xdr, 4);
 	if (unlikely(p == NULL))
 		return -EIO;
 
-	size = ntohl(*p++);
+	size = be32_to_cpup(p);
 	if (size > NFS3_FHSIZE || size == 0)
 		return -EIO;
 
@@ -421,23 +416,23 @@ static int decode_auth_flavors(struct xdr_stream *xdr, struct mountres *res)
 	if (*count == 0)
 		return 0;
 
-	p = xdr_inline_decode(xdr, sizeof(entries));
+	p = xdr_inline_decode(xdr, 4);
 	if (unlikely(p == NULL))
 		return -EIO;
-	entries = ntohl(*p);
+	entries = be32_to_cpup(p);
 	dprintk("NFS: received %u auth flavors\n", entries);
 	if (entries > NFS_MAX_SECFLAVORS)
 		entries = NFS_MAX_SECFLAVORS;
 
-	p = xdr_inline_decode(xdr, sizeof(u32) * entries);
+	p = xdr_inline_decode(xdr, 4 * entries);
 	if (unlikely(p == NULL))
 		return -EIO;
 
 	if (entries > *count)
 		entries = *count;
 
 	for (i = 0; i < entries; i++) {
-		flavors[i] = ntohl(*p++);
+		flavors[i] = be32_to_cpup(p++);
 		dprintk("NFS:   auth flavor[%u]: %d\n", i, flavors[i]);
 	}
 	*count = i;