NFS: Micro-optimize nfs4_decode_dirent()

Make the decoding of NFSv4 directory entries slightly more efficient
by:

  1.  Avoiding unnecessary byte swapping when checking XDR booleans,
      and

  2.  Not bumping "p" when its value will be immediately replaced by
      xdr_inline_decode()

This commit makes nfs4_decode_dirent() consistent with similar logic
in the other two decode_dirent() functions.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index 2ab8e5cb8f59f6410c4e407e90bd70ddaefd9fc9..009aef9e12bc3d5a5cef83b659da8f67251983b0 100644 (file)
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -6086,11 +6086,11 @@ int nfs4_decode_dirent(struct xdr_stream *xdr, struct nfs_entry *entry,
        __be32 *p = xdr_inline_decode(xdr, 4);
        if (unlikely(!p))
                goto out_overflow;
-       if (!ntohl(*p++)) {
+       if (*p == xdr_zero) {
                p = xdr_inline_decode(xdr, 4);
                if (unlikely(!p))
                        goto out_overflow;
-               if (!ntohl(*p++))
+               if (*p == xdr_zero)
                        return -EAGAIN;
                entry->eof = 1;
                return -EBADCOOKIE;
@@ -6101,7 +6101,7 @@ int nfs4_decode_dirent(struct xdr_stream *xdr, struct nfs_entry *entry,
                goto out_overflow;
        entry->prev_cookie = entry->cookie;
        p = xdr_decode_hyper(p, &entry->cookie);
-       entry->len = ntohl(*p++);
+       entry->len = be32_to_cpup(p);
 
        p = xdr_inline_decode(xdr, entry->len);
        if (unlikely(!p))