fuse: use offset_in_page() for page offset calculations

Replace open-coded (x & ~PAGE_MASK) with offset_in_page().

Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Horst Birthelmer <hbirthelmer@ddn.com>
Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Reviewed-by: Jingbo Xu <jefflexu@linux.alibaba.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

Author: joannekoong

fs/fuse/readdir.c

@@ -52,7 +52,7 @@ static void fuse_add_dirent_to_cache(struct file *file,
 	}
 	version = fi->rdc.version;
 	size = fi->rdc.size;
-	offset = size & ~PAGE_MASK;
+	offset = offset_in_page(size);
 	index = size >> PAGE_SHIFT;
 	/* Dirent doesn't fit in current page?  Jump to next page. */
 	if (offset + reclen > PAGE_SIZE) {
@@ -392,7 +392,7 @@ static enum fuse_parse_result fuse_parse_cache(struct fuse_file *ff,
 					       void *addr, unsigned int size,
 					       struct dir_context *ctx)
 {
-	unsigned int offset = ff->readdir.cache_off & ~PAGE_MASK;
+	unsigned int offset = offset_in_page(ff->readdir.cache_off);
 	enum fuse_parse_result res = FOUND_NONE;
 
 	WARN_ON(offset >= size);
@@ -518,13 +518,13 @@ static int fuse_readdir_cached(struct file *file, struct dir_context *ctx)
 	index = ff->readdir.cache_off >> PAGE_SHIFT;
 
 	if (index == (fi->rdc.size >> PAGE_SHIFT))
-		size = fi->rdc.size & ~PAGE_MASK;
+		size = offset_in_page(fi->rdc.size);
 	else
 		size = PAGE_SIZE;
 	spin_unlock(&fi->rdc.lock);
 
 	/* EOF? */
-	if ((ff->readdir.cache_off & ~PAGE_MASK) == size)
+	if (offset_in_page(ff->readdir.cache_off) == size)
 		return 0;
 
 	page = find_get_page_flags(file->f_mapping, index,