nfs: make the buf_to_pages_noslab function available to the nfs code

Make the buf_to_pages_noslab function available to the rest of the NFS
code. Rename it to nfs4_buf_to_pages_noslab to be consistent.

This will be used later in the NFSv4.2 xattr code.
Signed-off-by: Frank van der Linden <fllinden@amazon.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

fs/nfs/nfs4_fs.h

@@ -328,6 +328,8 @@ extern void nfs4_update_changeattr(struct inode *dir,
 				   struct nfs4_change_info *cinfo,
 				   unsigned long timestamp,
 				   unsigned long cache_validity);
+extern int nfs4_buf_to_pages_noslab(const void *buf, size_t buflen,
+				    struct page **pages);
 
 #if defined(CONFIG_NFS_V4_1)
 extern int nfs41_sequence_done(struct rpc_task *, struct nfs4_sequence_res *);

fs/nfs/nfs4proc.c

@@ -5541,7 +5541,7 @@ static inline int nfs4_server_supports_acls(struct nfs_server *server)
  */
 #define NFS4ACL_MAXPAGES DIV_ROUND_UP(XATTR_SIZE_MAX, PAGE_SIZE)
 
-static int buf_to_pages_noslab(const void *buf, size_t buflen,
+int nfs4_buf_to_pages_noslab(const void *buf, size_t buflen,
 		struct page **pages)
 {
 	struct page *newpage, **spages;
@@ -5783,7 +5783,7 @@ static int __nfs4_proc_set_acl(struct inode *inode, const void *buf, size_t bufl
 		return -EOPNOTSUPP;
 	if (npages > ARRAY_SIZE(pages))
 		return -ERANGE;
-	i = buf_to_pages_noslab(buf, buflen, arg.acl_pages);
+	i = nfs4_buf_to_pages_noslab(buf, buflen, arg.acl_pages);
 	if (i < 0)
 		return i;
 	nfs4_inode_make_writeable(inode);