2023-12-19 13:04:53

by chenguanxi11234

Subject: [PATCH linux-next v2] kernel/power: Use kmap_local_page() in snapshot.c

From: Chen Haonan <[email protected]>

2023-12-19 19:57:23

by Rafael J. Wysocki

Subject: Re: [PATCH linux-next v2] kernel/power: Use kmap_local_page() in snapshot.c

On Tue, Dec 19, 2023 at 2:19 PM <[email protected]> wrote:
>
> From: Chen Haonan <[email protected]>
>
> kmap_atomic() has been deprecated in favor of kmap_local_page().
>
> kmap_atomic() disables page-faults and preemption (the latter
> only for !PREEMPT_RT kernels).The code between the mapping and
> un-mapping in this patch does not depend on the above-mentioned
> side effects.So simply replaced kmap_atomic() with kmap_local_page().
>
> Signed-off-by: Chen Haonan <[email protected]>
> ---
> kernel/power/snapshot.c | 12 ++++++------
> 1 file changed, 6 insertions(+), 6 deletions(-)
> diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
> index e3e8f1c6e75f..5c96ff067c64 100644
> --- a/kernel/power/snapshot.c
> +++ b/kernel/power/snapshot.c
> @@ -1487,11 +1487,11 @@ static bool copy_data_page(unsigned long dst_pfn, unsigned long src_pfn)
> s_page = pfn_to_page(src_pfn);
> d_page = pfn_to_page(dst_pfn);
> if (PageHighMem(s_page)) {
> - src = kmap_atomic(s_page);
> - dst = kmap_atomic(d_page);
> + src = kmap_local_page(s_page);
> + dst = kmap_local_page(d_page);
> zeros_only = do_copy_page(dst, src);
> - kunmap_atomic(dst);
> - kunmap_atomic(src);
> + kunmap_local(dst);
> + kunmap_local(src);
> } else {
> if (PageHighMem(d_page)) {
> /*
> @@ -1499,9 +1499,9 @@ static bool copy_data_page(unsigned long dst_pfn, unsigned long src_pfn)
> * data modified by kmap_atomic()
> */
> zeros_only = safe_copy_page(buffer, s_page);
> - dst = kmap_atomic(d_page);
> + dst = kmap_local_page(d_page);
> copy_page(dst, buffer);
> - kunmap_atomic(dst);
> + kunmap_local(dst);
> } else {
> zeros_only = safe_copy_page(page_address(d_page), s_page);
> }
> --

Applied (under edited subject) as 6.8 material, thanks!