NFSD: De-duplicate nfsd4_decode_bitmap4()

Clean up. Trond points out that xdr_stream_decode_uint32_array()
does the same thing as nfsd4_decode_bitmap4().
Suggested-by: Trond Myklebust <trondmy@hammerspace.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

fs/nfsd/nfs4xdr.c

@@ -277,21 +277,10 @@ nfsd4_decode_verifier4(struct nfsd4_compoundargs *argp, nfs4_verifier *verf)
 static __be32
 nfsd4_decode_bitmap4(struct nfsd4_compoundargs *argp, u32 *bmval, u32 bmlen)
 {
-	u32 i, count;
-	__be32 *p;
-
-	if (xdr_stream_decode_u32(argp->xdr, &count) < 0)
-		return nfserr_bad_xdr;
-	/* request sanity */
-	if (count > 1000)
-		return nfserr_bad_xdr;
-	p = xdr_inline_decode(argp->xdr, count << 2);
-	if (!p)
-		return nfserr_bad_xdr;
-	for (i = 0; i < bmlen; i++)
-		bmval[i] = (i < count) ? be32_to_cpup(p++) : 0;
+	ssize_t status;
 
-	return nfs_ok;
+	status = xdr_stream_decode_uint32_array(argp->xdr, bmval, bmlen);
+	return status == -EBADMSG ? nfserr_bad_xdr : nfs_ok;
 }
 
 static __be32