hfsplus: fix warning with 64k PAGE_SIZE

fs/hfsplus/btree.c: In function 'hfsplus_bmap_alloc':
fs/hfsplus/btree.c:239: warning: comparison is always false due to limited range of data type

But this might hide a real bug?

Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/hfsplus/btree.c

@@ -184,7 +184,9 @@ struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree)
 	struct hfs_bnode *node, *next_node;
 	struct page **pagep;
 	u32 nidx, idx;
-	u16 off, len;
+	unsigned off;
+	u16 off16;
+	u16 len;
 	u8 *data, byte, m;
 	int i;
 
@@ -211,7 +213,8 @@ struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree)
 	node = hfs_bnode_find(tree, nidx);
 	if (IS_ERR(node))
 		return node;
-	len = hfs_brec_lenoff(node, 2, &off);
+	len = hfs_brec_lenoff(node, 2, &off16);
+	off = off16;
 
 	off += node->page_offset;
 	pagep = node->page + (off >> PAGE_CACHE_SHIFT);
@@ -256,7 +259,8 @@ struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree)
 			return next_node;
 		node = next_node;
 
-		len = hfs_brec_lenoff(node, 0, &off);
+		len = hfs_brec_lenoff(node, 0, &off16);
+		off = off16;
 		off += node->page_offset;
 		pagep = node->page + (off >> PAGE_CACHE_SHIFT);
 		data = kmap(*pagep);