The patch titled
Subject: swap: remove get/put_swap_device() in __swap_duplicate()
has been added to the -mm mm-unstable branch. Its filename is
swap-remove-get-put_swap_device-in-__swap_duplicate.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/swap-remove-get-put_swap_device-in-__swap_duplicate.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Huang Ying <ying.huang@xxxxxxxxx>
Subject: swap: remove get/put_swap_device() in __swap_duplicate()
Date: Mon, 29 May 2023 14:13:54 +0800
__swap_duplicate() is called by
- swap_shmem_alloc(): the folio in swap cache is locked.
- copy_nonpresent_pte() -> swap_duplicate() and try_to_unmap_one() ->
swap_duplicate(): the page table lock is held.
- __read_swap_cache_async() -> swapcache_prepare(): enclosed with
get/put_swap_device() in __read_swap_cache_async() already.
So, it's safe to remove get/put_swap_device() in __swap_duplicate().
Link: https://lkml.kernel.org/r/20230529061355.125791-5-ying.huang@xxxxxxxxx
Signed-off-by: "Huang, Ying" <ying.huang@xxxxxxxxx>
Reviewed-by: Yosry Ahmed <yosryahmed@xxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Tim Chen <tim.c.chen@xxxxxxxxxxxxxxx>
Cc: Yang Shi <shy828301@xxxxxxxxx>
Cc: Yu Zhao <yuzhao@xxxxxxxxxx>
Cc: Chris Li <chrisl@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/swapfile.c | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)
--- a/mm/swapfile.c~swap-remove-get-put_swap_device-in-__swap_duplicate
+++ a/mm/swapfile.c
@@ -3265,9 +3265,7 @@ static int __swap_duplicate(swp_entry_t
unsigned char has_cache;
int err;
- p = get_swap_device(entry);
- if (!p)
- return -EINVAL;
+ p = swp_swap_info(entry);
offset = swp_offset(entry);
ci = lock_cluster_or_swap_info(p, offset);
@@ -3314,7 +3312,6 @@ static int __swap_duplicate(swp_entry_t
unlock_out:
unlock_cluster_or_swap_info(p, ci);
- put_swap_device(p);
return err;
}
_
Patches currently in -mm which might be from ying.huang@xxxxxxxxx are
migrate_pages_batch-simplify-retrying-and-failure-counting-of-large-folios.patch
swap-remove-get-put_swap_device-in-__swap_count.patch
swap-__read_swap_cache_async-enlarge-get-put_swap_device-protection-range.patch
swap-remove-__swp_swapcount.patch
swap-remove-get-put_swap_device-in-__swap_duplicate.patch
swap-comments-get_swap_device-with-usage-rule.patch
