From b1e1ef345433fb03742003677ddfb980d148092b Mon Sep 17 00:00:00 2001 From: Yang Shi Date: Thu, 19 Aug 2021 19:04:05 -0700 Subject: Revert "mm/shmem: fix shmem_swapin() race with swapoff" Due to the change about how block layer detects congestion the justification of commit 8fd2e0b505d1 ("mm: swap: check if swap backing device is congested or not") doesn't stand anymore, so the commit could be just reverted in order to solve the race reported by commit 2efa33fc7f6e ("mm/shmem: fix shmem_swapin() race with swapoff"), so the fix commit could be just reverted as well. And that fix is also kind of buggy as discussed by [1] and [2]. [1] https://lore.kernel.org/linux-mm/24187e5e-069-9f3f-cefe-39ac70783753@google.com/ [2] https://lore.kernel.org/linux-mm/e82380b9-3ad4-4a52-be50-6d45c7f2b5da@google.com/ Link: https://lkml.kernel.org/r/20210810202936.2672-2-shy828301@gmail.com Signed-off-by: Yang Shi Suggested-by: Hugh Dickins Acked-by: Hugh Dickins Cc: "Huang, Ying" Cc: Miaohe Lin Cc: David Hildenbrand Cc: Johannes Weiner Cc: Joonsoo Kim Cc: Matthew Wilcox (Oracle) Cc: Michal Hocko Cc: Minchan Kim Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/shmem.c | 14 +------------- 1 file changed, 1 insertion(+), 13 deletions(-) (limited to 'mm/shmem.c') diff --git a/mm/shmem.c b/mm/shmem.c index 70d9ce294bb4..dacda7463d54 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1696,8 +1696,7 @@ static int shmem_swapin_page(struct inode *inode, pgoff_t index, struct address_space *mapping = inode->i_mapping; struct shmem_inode_info *info = SHMEM_I(inode); struct mm_struct *charge_mm = vma ? vma->vm_mm : NULL; - struct swap_info_struct *si; - struct page *page = NULL; + struct page *page; swp_entry_t swap; int error; @@ -1705,12 +1704,6 @@ static int shmem_swapin_page(struct inode *inode, pgoff_t index, swap = radix_to_swp_entry(*pagep); *pagep = NULL; - /* Prevent swapoff from happening to us. */ - si = get_swap_device(swap); - if (!si) { - error = EINVAL; - goto failed; - } /* Look it up and read it in.. */ page = lookup_swap_cache(swap, NULL, 0); if (!page) { @@ -1772,8 +1765,6 @@ static int shmem_swapin_page(struct inode *inode, pgoff_t index, swap_free(swap); *pagep = page; - if (si) - put_swap_device(si); return 0; failed: if (!shmem_confirm_swap(mapping, index, swap)) @@ -1784,9 +1775,6 @@ unlock: put_page(page); } - if (si) - put_swap_device(si); - return error; } -- cgit v1.2.3