The patch titled
Subject: Revert "mm/shmem: fix shmem_swapin() race with swapoff"
has been added to the -mm tree. Its filename is
revert-mm-shmem-fix-shmem_swapin-race-with-swapoff.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/revert-mm-shmem-fix-shmem_swapin-race-with-swapoff.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/revert-mm-shmem-fix-shmem_swapin-race-with-swapoff.patch
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The -mm tree is included into linux-next and is updated
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------------------------------------------------------
From: Yang Shi <shy828301@xxxxxxxxx>
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@xxxxxxxxxx/
[2] https://lore.kernel.org/linux-mm/e82380b9-3ad4-4a52-be50-6d45c7f2b5da@xxxxxxxxxx/
Link: https://lkml.kernel.org/r/20210810202936.2672-2-shy828301@xxxxxxxxx
Signed-off-by: Yang Shi <shy828301@xxxxxxxxx>
Suggested-by: Hugh Dickins <hughd@xxxxxxxxxx>
Acked-by: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: "Huang, Ying" <ying.huang@xxxxxxxxx>
Cc: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/shmem.c | 14 +-------------
1 file changed, 1 insertion(+), 13 deletions(-)
--- a/mm/shmem.c~revert-mm-shmem-fix-shmem_swapin-race-with-swapoff
+++ a/mm/shmem.c
@@ -1696,8 +1696,7 @@ static int shmem_swapin_page(struct inod
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 inod
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 inod
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;
}
_
Patches currently in -mm which might be from shy828301@xxxxxxxxx are
revert-mm-shmem-fix-shmem_swapin-race-with-swapoff.patch
revert-mm-swap-check-if-swap-backing-device-is-congested-or-not.patch
