__swap_duplicate() is called by - swap_shmem_alloc(): the page lock of the swap cache is held. - 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(). Signed-off-by: "Huang, Ying" <ying.huang@xxxxxxxxx> 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> --- mm/swapfile.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) diff --git a/mm/swapfile.c b/mm/swapfile.c index e9cce775fb25..4dbaea64635d 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -3264,9 +3264,7 @@ static int __swap_duplicate(swp_entry_t entry, unsigned char usage) 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); @@ -3313,7 +3311,6 @@ static int __swap_duplicate(swp_entry_t entry, unsigned char usage) unlock_out: unlock_cluster_or_swap_info(p, ci); - put_swap_device(p); return err; } -- 2.39.2
