[PATCH -V3 1/5] swap: Remove get/put_swap_device() in __swap_count()

Huang Ying
2023-05-29T06:14:26Z

get/put_swap_device() are added to __swap_count() in commit
eb085574a752 ("mm, swap: fix race between swapoff and some swap
operations"). Later, in commit 2799e77529c2 ("swap: fix
do_swap_page() race with swapoff"), get/put_swap_device() are added to
do_swap_page(). And they enclose the only call site of
__swap_count(). So, it's safe to remove get/put_swap_device() in
__swap_count() now.

Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: Yosry Ahmed <yosryahmed@google.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Chris Li <chrisl@kernel.org>
---
mm/swapfile.c | 10 ++--------
1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/mm/swapfile.c b/mm/swapfile.c
index 274bbf797480..8419cba9c192 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1432,16 +1432,10 @@ void swapcache_free_entries(swp_entry_t *entries, int n)

int __swap_count(swp_entry_t entry)
{
- struct swap_info_struct *si;
+ struct swap_info_struct *si = swp_swap_info(entry);
pgoff_t offset = swp_offset(entry);
- int count = 0;

- si = get_swap_device(entry);
- if (si) {
- count = swap_count(si->swap_map[offset]);
- put_swap_device(si);
- }
- return count;
+ return swap_count(si->swap_map[offset]);
}

/*
--
2.39.2