OpenCloudOS-Kernel/fs/btrfs/subpage.c

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// SPDX-License-Identifier: GPL-2.0
#include <linux/slab.h>
#include "ctree.h"
#include "subpage.h"
int btrfs_attach_subpage(const struct btrfs_fs_info *fs_info,
struct page *page, enum btrfs_subpage_type type)
{
struct btrfs_subpage *subpage;
/*
* We have cases like a dummy extent buffer page, which is not mappped
* and doesn't need to be locked.
*/
if (page->mapping)
ASSERT(PageLocked(page));
/* Either not subpage, or the page already has private attached */
if (fs_info->sectorsize == PAGE_SIZE || PagePrivate(page))
return 0;
subpage = kzalloc(sizeof(struct btrfs_subpage), GFP_NOFS);
if (!subpage)
return -ENOMEM;
spin_lock_init(&subpage->lock);
attach_page_private(page, subpage);
return 0;
}
void btrfs_detach_subpage(const struct btrfs_fs_info *fs_info,
struct page *page)
{
struct btrfs_subpage *subpage;
/* Either not subpage, or already detached */
if (fs_info->sectorsize == PAGE_SIZE || !PagePrivate(page))
return;
subpage = (struct btrfs_subpage *)detach_page_private(page);
ASSERT(subpage);
kfree(subpage);
}