buffer: have alloc_page_buffers() use __GFP_NOFAIL
Instead of adding weird retry logic in that function, utilize
__GFP_NOFAIL to ensure that the vm takes care of handling any
potential retries appropriately. This means we don't have to
call free_more_memory() from here.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/fs/buffer.c b/fs/buffer.c
index 170df85..1234ae3 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -861,16 +861,19 @@ int remove_inode_buffers(struct inode *inode)
* which may not fail from ordinary buffer allocations.
*/
struct buffer_head *alloc_page_buffers(struct page *page, unsigned long size,
- int retry)
+ bool retry)
{
struct buffer_head *bh, *head;
+ gfp_t gfp = GFP_NOFS;
long offset;
-try_again:
+ if (retry)
+ gfp |= __GFP_NOFAIL;
+
head = NULL;
offset = PAGE_SIZE;
while ((offset -= size) >= 0) {
- bh = alloc_buffer_head(GFP_NOFS);
+ bh = alloc_buffer_head(gfp);
if (!bh)
goto no_grow;
@@ -896,23 +899,7 @@ struct buffer_head *alloc_page_buffers(struct page *page, unsigned long size,
} while (head);
}
- /*
- * Return failure for non-async IO requests. Async IO requests
- * are not allowed to fail, so we have to wait until buffer heads
- * become available. But we don't want tasks sleeping with
- * partially complete buffers, so all were released above.
- */
- if (!retry)
- return NULL;
-
- /* We're _really_ low on memory. Now we just
- * wait for old buffer heads to become free due to
- * finishing IO. Since this is an async request and
- * the reserve list is empty, we're sure there are
- * async buffer heads in use.
- */
- free_more_memory();
- goto try_again;
+ return NULL;
}
EXPORT_SYMBOL_GPL(alloc_page_buffers);
@@ -1021,7 +1008,7 @@ grow_dev_page(struct block_device *bdev, sector_t block,
/*
* Allocate some buffers for this page
*/
- bh = alloc_page_buffers(page, size, 0);
+ bh = alloc_page_buffers(page, size, false);
if (!bh)
goto failed;
@@ -1575,7 +1562,7 @@ void create_empty_buffers(struct page *page,
{
struct buffer_head *bh, *head, *tail;
- head = alloc_page_buffers(page, blocksize, 1);
+ head = alloc_page_buffers(page, blocksize, true);
bh = head;
do {
bh->b_state |= b_state;
@@ -2638,7 +2625,7 @@ int nobh_write_begin(struct address_space *mapping,
* Be careful: the buffer linked list is a NULL terminated one, rather
* than the circular one we're used to.
*/
- head = alloc_page_buffers(page, blocksize, 0);
+ head = alloc_page_buffers(page, blocksize, false);
if (!head) {
ret = -ENOMEM;
goto out_release;