btrfs: Refactor loop in btrfs_release_extent_buffer_page

The purpose of the function is to free all the pages comprising an
extent buffer. This can be achieved with a simple for loop rather than
the slightly more involved 'do {} while' construct. So rewrite the
loop using a 'for' construct. Additionally we can never have an
extent_buffer that has 0 pages so remove the check for index == 0. No
functional changes.

The reversed order used to have a meaning in the past where the first
page served as a blocking point for several callers. See eg
4f2de97ace ("Btrfs: set page->private to the eb").

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Nikolay Borisov 2018-06-27 16:38:22 +03:00 committed by David Sterba
parent b16d011e79
commit d64766fdf9

View File

@ -4647,19 +4647,16 @@ int extent_buffer_under_io(struct extent_buffer *eb)
*/
static void btrfs_release_extent_buffer_page(struct extent_buffer *eb)
{
int index;
struct page *page;
int i;
int num_pages;
int mapped = !test_bit(EXTENT_BUFFER_DUMMY, &eb->bflags);
BUG_ON(extent_buffer_under_io(eb));
index = num_extent_pages(eb);
if (index == 0)
return;
num_pages = num_extent_pages(eb);
for (i = 0; i < num_pages; i++) {
struct page *page = eb->pages[i];
do {
index--;
page = eb->pages[index];
if (!page)
continue;
if (mapped)
@ -4691,7 +4688,7 @@ static void btrfs_release_extent_buffer_page(struct extent_buffer *eb)
/* One for when we allocated the page */
put_page(page);
} while (index != 0);
}
}
/*