nfs: fix sparse warnings

fs/nfs/nfs4state.c:788:34: warning: Using plain integer as NULL pointer
fs/nfs/delegation.c:52:34: warning: Using plain integer as NULL pointer
fs/nfs/idmap.c:312:12: warning: Using plain integer as NULL pointer
fs/nfs/callback_xdr.c:257:6: warning: Using plain integer as NULL pointer
fs/nfs/callback_xdr.c:270:6: warning: Using plain integer as NULL pointer
fs/nfs/callback_xdr.c:281:6: warning: Using plain integer as NULL pointer

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/callback_xdr.c

@@ -254,7 +254,7 @@ static __be32 encode_attr_change(struct xdr_stream *xdr, const uint32_t *bitmap,
 	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 @@ static __be32 encode_attr_size(struct xdr_stream *xdr, const uint32_t *bitmap, u
 	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 @@ static __be32 encode_attr_time(struct xdr_stream *xdr, const struct timespec *ti
 	__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);

fs/nfs/delegation.c

@@ -49,7 +49,7 @@ static int nfs_delegation_claim_locks(struct nfs_open_context *ctx, struct nfs4_
 	struct file_lock *fl;
 	int status;
 
-	for (fl = inode->i_flock; fl != 0; fl = fl->fl_next) {
+	for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {
 		if (!(fl->fl_flags & (FL_POSIX|FL_FLOCK)))
 			continue;
 		if (nfs_file_open_context(fl->fl_file) != ctx)

fs/nfs/idmap.c

@@ -309,7 +309,7 @@ nfs_idmap_name(struct idmap *idmap, struct idmap_hashtable *h,
 	mutex_lock(&idmap->idmap_im_lock);
 
 	he = idmap_lookup_id(h, id);
-	if (he != 0) {
+	if (he) {
 		memcpy(name, he->ih_name, he->ih_namelen);
 		ret = he->ih_namelen;
 		goto out;

fs/nfs/nfs4state.c

@@ -785,7 +785,7 @@ static int nfs4_reclaim_locks(struct nfs4_state_recovery_ops *ops, struct nfs4_s
 	struct file_lock *fl;
 	int status = 0;
 
-	for (fl = inode->i_flock; fl != 0; fl = fl->fl_next) {
+	for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {
 		if (!(fl->fl_flags & (FL_POSIX|FL_FLOCK)))
 			continue;
 		if (nfs_file_open_context(fl->fl_file)->state != state)