Yin Fengwei wrote:
> zero_user_folio_segments() has same function as zero_user_segments().
> but take folio as parameter. Update folio_zero_segments(),
> folio_zero_segment() and folio_zero_range() to use it.
>
> Signed-off-by: Yin Fengwei <fengwei.yin@xxxxxxxxx>
> ---
> include/linux/highmem.h | 26 +++++++++++++++++---
> mm/highmem.c | 53 +++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 76 insertions(+), 3 deletions(-)
>
> diff --git a/include/linux/highmem.h b/include/linux/highmem.h
> index b06254e76d99..0039116e416a 100644
> --- a/include/linux/highmem.h
> +++ b/include/linux/highmem.h
> @@ -266,6 +266,8 @@ static inline void tag_clear_highpage(struct page *page)
> #ifdef CONFIG_HIGHMEM
> void zero_user_segments(struct page *page, unsigned start1, unsigned end1,
> unsigned start2, unsigned end2);
> +void zero_user_folio_segments(struct folio *folio, unsigned start1,
> + unsigned end1, unsigned start2, unsigned end2);
> #else
> static inline void zero_user_segments(struct page *page,
> unsigned start1, unsigned end1,
> @@ -286,6 +288,24 @@ static inline void zero_user_segments(struct page *page,
> for (i = 0; i < compound_nr(page); i++)
> flush_dcache_page(page + i);
> }
> +
> +static inline void zero_user_folio_segments(struct folio *folio,
> + unsigned start1, unsigned end1,
> + unsigned start2, unsigned end2)
> +{
> + void *kaddr = kmap_local_page(&folio->page);
> +
> + BUG_ON(end1 > folio_size(folio) || end2 > folio_size(folio));
> +
> + if (end1 > start1)
> + memset(kaddr + start1, 0, end1 - start1);
> +
> + if (end2 > start2)
> + memset(kaddr + start2, 0, end2 - start2);
> +
> + kunmap_local(kaddr);
> + flush_dcache_folio(folio);
> +}
> #endif
>
> static inline void zero_user_segment(struct page *page,
> @@ -454,7 +474,7 @@ static inline size_t memcpy_from_file_folio(char *to, struct folio *folio,
> static inline void folio_zero_segments(struct folio *folio,
> size_t start1, size_t xend1, size_t start2, size_t xend2)
> {
> - zero_user_segments(&folio->page, start1, xend1, start2, xend2);
> + zero_user_folio_segments(folio, start1, xend1, start2, xend2);
> }
>
> /**
> @@ -466,7 +486,7 @@ static inline void folio_zero_segments(struct folio *folio,
> static inline void folio_zero_segment(struct folio *folio,
> size_t start, size_t xend)
> {
> - zero_user_segments(&folio->page, start, xend, 0, 0);
> + zero_user_folio_segments(folio, start, xend, 0, 0);
> }
>
> /**
> @@ -478,7 +498,7 @@ static inline void folio_zero_segment(struct folio *folio,
> static inline void folio_zero_range(struct folio *folio,
> size_t start, size_t length)
> {
> - zero_user_segments(&folio->page, start, start + length, 0, 0);
> + zero_user_folio_segments(folio, start, start + length, 0, 0);
> }
>
> #endif /* _LINUX_HIGHMEM_H */
> diff --git a/mm/highmem.c b/mm/highmem.c
> index db251e77f98f..e234b249208f 100644
> --- a/mm/highmem.c
> +++ b/mm/highmem.c
> @@ -443,6 +443,59 @@ void zero_user_segments(struct page *page, unsigned start1, unsigned end1,
> BUG_ON((start1 | start2 | end1 | end2) != 0);
> }
> EXPORT_SYMBOL(zero_user_segments);
> +
> +static inline void zero_user_folio_segment(struct folio *folio,
FWIW this does not compile:
s/zero_user_folio_segment/zero_user_folio_segments/
But I agree with Willy here that I don't see the point of this patch.
Seems like a lot of extra code for no benefit.
Ira
> + unsigned start1, unsigned end1,
> + unsigned start2, unsigned end2)
> +{
> + void *kaddr;
> + unsigned s;
> +
> + BUG_ON(end1 > folio_size(folio) || end2 > folio_size(folio));
> +
> + if (start1 > start2) {
> + swap(start1, start2);
> + swap(end1, end2);
> + }
> +
> + if (start1 >= end1)
> + start1 = end1 = 0;
> +
> + if (start2 >= end2)
> + start2 = end2 = 0;
> +
> + start2 = max_t(unsigned, end1, start2);
> + s = start1;
> + while((start1 < end1) || (start2 < end2)) {
> + kaddr = kmap_local_folio(folio,
> + offset_in_folio(folio, PAGE_ALIGN_DOWN(s)));
> +
> + if ((end2 > start2) && (end1 >= start1)) {
> + unsigned this_end = min_t(unsigned, end2,
> + PAGE_ALIGN_DOWN(start2) + PAGE_SIZE);
> +
> + memset(kaddr + offset_in_page(start2), 0,
> + this_end - start2);
> +
> + start2 = this_end;
> + }
> +
> + if (end1 > start1) {
> + unsigned this_end = min_t(unsigned, end1,
> + PAGE_ALIGN_DOWN(start1) + PAGE_SIZE);
> +
> + memset(kaddr + offset_in_page(start1), 0,
> + this_end - start1);
> + s = start1 = this_end;
> + } else {
> + s = start2;
> + }
> + kunmap_local(kaddr);
> + }
> +
> + flush_dcache_folio(folio);
> +}
> +EXPORT_SYMBOL(zero_user_folio_segments);
> #endif /* CONFIG_HIGHMEM */
>
> #ifdef CONFIG_KMAP_LOCAL
> --
> 2.30.2
>
>
