On 2021/4/13 9:33, Huang, Ying wrote:
> Miaohe Lin <linmiaohe@xxxxxxxxxx> writes:
>
>> The function get_shadow_from_swap_cache() can race with swapoff, though
>> it's only called by do_swap_page() now.
>>
>> Fixes: aae466b0052e ("mm/swap: implement workingset detection for anonymous LRU")
>> Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
>
> This is unnecessary. The only caller has guaranteed the swap device
> from swapoff
Ok. This patch is just in case get_shadow_from_swap_cache() would be
called from elsewhere someday.
It's unnecessary and can be dropped now
.
>
> Best Regards,
> Huang, Ying
>
>> ---
>> mm/swap_state.c | 9 ++++++---
>> 1 file changed, 6 insertions(+), 3 deletions(-)
>>
>> diff --git a/mm/swap_state.c b/mm/swap_state.c
>> index 272ea2108c9d..709c260d644a 100644
>> --- a/mm/swap_state.c
>> +++ b/mm/swap_state.c
>> @@ -83,11 +83,14 @@ void show_swap_cache_info(void)
>>
>> void *get_shadow_from_swap_cache(swp_entry_t entry)
>> {
>> - struct address_space *address_space = swap_address_space(entry);
>> - pgoff_t idx = swp_offset(entry);
>> + struct swap_info_struct *si;
>> struct page *page;
>>
>> - page = xa_load(&address_space->i_pages, idx);
>> + si = get_swap_device(entry);
>> + if (!si)
>> + return NULL;
>> + page = xa_load(&swap_address_space(entry)->i_pages, swp_offset(entry));
>> + put_swap_device(si);
>> if (xa_is_value(page))
>> return page;
>> return NULL;
>
> .
>
