Commit 92751dfb authored by ZhangPeng's avatar ZhangPeng Committed by Ma Wupeng
Browse files

userswap: add page_count() check for swap-out VA 

hulk inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I6CAIM



--------------------------------

Add page_count() check for swap-out VA to make sure that no other kernel
mechanism is using this physical page.
Add lru_add_drain_all() before swap-out VA to correct page_count() of
swap-out pages.

Signed-off-by: default avatarZhangPeng <zhangpeng362@huawei.com>
parent 4ca4ac49

mm/userswap.c

+3 −1
Original line number Diff line number Diff line
@@ -139,7 +139,8 @@ static unsigned long pages_can_be_swapped(struct mm_struct *mm, 
		 * Check that no O_DIRECT or similar I/O is in progress on the

		 * page

		 */

		if (page_mapcount(page) > 1) {

		if (page_mapcount(page) > 1 ||

		    page_mapcount(page) + 1 != page_count(page)) {

			ret = -EBUSY;

			goto out_err;

		}
@@ -378,6 +379,7 @@ unsigned long uswap_mremap(unsigned long old_addr, unsigned long old_len, 
	if (old_addr + old_len > new_addr && new_addr + new_len > old_addr)

		return ret;



	lru_add_drain_all();

	down_read(&mm->mmap_lock);

	ret = pages_can_be_swapped(mm, old_addr, len, &pages);

	if (ret) {