On Tue, Jul 21, 2020 at 11:27 PM Christoph Hellwig <hch@xxxxxx> wrote:
>
> There is no point in trying to call bdev_read_page if SWP_SYNCHRONOUS_IO
> is not set, as the device won't support it.
>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> ---
> mm/page_io.c | 18 ++++++++++--------
> 1 file changed, 10 insertions(+), 8 deletions(-)
>
> diff --git a/mm/page_io.c b/mm/page_io.c
> index ccda7679008851..442061348dfb26 100644
> --- a/mm/page_io.c
> +++ b/mm/page_io.c
> @@ -403,15 +403,17 @@ int swap_readpage(struct page *page, bool synchronous)
> goto out;
> }
>
> - ret = bdev_read_page(sis->bdev, swap_page_sector(page), page);
> - if (!ret) {
> - if (trylock_page(page)) {
> - swap_slot_free_notify(page);
> - unlock_page(page);
> - }
> + if (sis->flags & SWP_SYNCHRONOUS_IO) {
> + ret = bdev_read_page(sis->bdev, swap_page_sector(page), page);
> + if (ret) {
!ret
> + if (trylock_page(page)) {
> + swap_slot_free_notify(page);
> + unlock_page(page);
> + }
>
> - count_vm_event(PSWPIN);
> - goto out;
> + count_vm_event(PSWPIN);
> + goto out;
> + }
> }
>
> ret = 0;
> --
> 2.27.0
>
