Commit 39107ccb authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Jens Axboe
Browse files

bcache: switch from pages to folios in read_super() 



Retrieve a folio from the page cache instead of a page. Removes a hidden
call to compound_head(). Then be sure to call folio_put() instead of
put_page() to release it. That doesn't save any calls to
compound_head(), just moves them around.

Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: default avatarColy Li <colyli@kernel.org>
Acked-back: Coly Li <colyli@kernel.org>
Link: https://lore.kernel.org/r/20250702024848.343370-1-colyli@kernel.org


[axboe: commit message massaging]
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 0a50ed05

drivers/md/bcache/super.c

+11 −11
Original line number Diff line number Diff line
@@ -168,14 +168,14 @@ static const char *read_super(struct cache_sb *sb, struct block_device *bdev, 
{

	const char *err;

	struct cache_sb_disk *s;

	struct page *page;

	struct folio *folio;

	unsigned int i;



	page = read_cache_page_gfp(bdev->bd_mapping,

	folio = mapping_read_folio_gfp(bdev->bd_mapping,

			SB_OFFSET >> PAGE_SHIFT, GFP_KERNEL);

	if (IS_ERR(page))

	if (IS_ERR(folio))

		return "IO error";

	s = page_address(page) + offset_in_page(SB_OFFSET);

	s = folio_address(folio) + offset_in_folio(folio, SB_OFFSET);



	sb->offset		= le64_to_cpu(s->offset);

	sb->version		= le64_to_cpu(s->version);
@@ -272,7 +272,7 @@ static const char *read_super(struct cache_sb *sb, struct block_device *bdev, 
	*res = s;

	return NULL;

err:

	put_page(page);

	folio_put(folio);

	return err;

}
@@ -1366,7 +1366,7 @@ static CLOSURE_CALLBACK(cached_dev_free) 
	mutex_unlock(&bch_register_lock);



	if (dc->sb_disk)

		put_page(virt_to_page(dc->sb_disk));

		folio_put(virt_to_folio(dc->sb_disk));



	if (dc->bdev_file)

		fput(dc->bdev_file);
@@ -2216,7 +2216,7 @@ void bch_cache_release(struct kobject *kobj) 
		free_fifo(&ca->free[i]);



	if (ca->sb_disk)

		put_page(virt_to_page(ca->sb_disk));

		folio_put(virt_to_folio(ca->sb_disk));



	if (ca->bdev_file)

		fput(ca->bdev_file);
@@ -2593,7 +2593,7 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr, 
	if (!holder) {

		ret = -ENOMEM;

		err = "cannot allocate memory";

		goto out_put_sb_page;

		goto out_put_sb_folio;

	}



	/* Now reopen in exclusive mode with proper holder */
@@ -2667,8 +2667,8 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr, 


out_free_holder:

	kfree(holder);

out_put_sb_page:

	put_page(virt_to_page(sb_disk));

out_put_sb_folio:

	folio_put(virt_to_folio(sb_disk));

out_blkdev_put:

	if (bdev_file)

		fput(bdev_file);