diff --git a/fs/nfs/callback_xdr.c b/fs/nfs/callback_xdr.c
index c63eb72..13619d2 100644
--- a/fs/nfs/callback_xdr.c
+++ b/fs/nfs/callback_xdr.c
@@ -254,7 +254,7 @@
 	if (!(bitmap[0] & FATTR4_WORD0_CHANGE))
 		return 0;
 	p = xdr_reserve_space(xdr, 8);
-	if (unlikely(p == 0))
+	if (unlikely(!p))
 		return htonl(NFS4ERR_RESOURCE);
 	p = xdr_encode_hyper(p, change);
 	return 0;
@@ -267,7 +267,7 @@
 	if (!(bitmap[0] & FATTR4_WORD0_SIZE))
 		return 0;
 	p = xdr_reserve_space(xdr, 8);
-	if (unlikely(p == 0))
+	if (unlikely(!p))
 		return htonl(NFS4ERR_RESOURCE);
 	p = xdr_encode_hyper(p, size);
 	return 0;
@@ -278,7 +278,7 @@
 	__be32 *p;
 
 	p = xdr_reserve_space(xdr, 12);
-	if (unlikely(p == 0))
+	if (unlikely(!p))
 		return htonl(NFS4ERR_RESOURCE);
 	p = xdr_encode_hyper(p, time->tv_sec);
 	*p = htonl(time->tv_nsec);