On Tue, Jun 13, 2023 at 05:53:44PM -0400, Peter Xu wrote:
> The only path that doesn't use generic "**pages" handling is the gate vma.
> Make it use the same path, meanwhile tune the next_page label upper to
> cover "**pages" handling. This prepares for THP handling for "**pages".
>
> Signed-off-by: Peter Xu <peterx@xxxxxxxxxx>
> ---
> mm/gup.c | 7 +++----
> 1 file changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/mm/gup.c b/mm/gup.c
> index 8d59ae4554e7..a2d1b3c4b104 100644
> --- a/mm/gup.c
> +++ b/mm/gup.c
> @@ -1135,7 +1135,7 @@ static long __get_user_pages(struct mm_struct *mm,
> if (!vma && in_gate_area(mm, start)) {
> ret = get_gate_page(mm, start & PAGE_MASK,
> gup_flags, &vma,
> - pages ? &pages[i] : NULL);
> + pages ? &page : NULL);
Good spot... ugh that we handled this differently.
> if (ret)
> goto out;
> ctx.page_mask = 0;
We can drop this line now right? As the new next_page block will duplicate
this.
> @@ -1205,19 +1205,18 @@ static long __get_user_pages(struct mm_struct *mm,
> ret = PTR_ERR(page);
> goto out;
> }
> -
> - goto next_page;
This is neat, we've already checked if pages != NULL so the if (pages)
block at the new next_page label will not be run.
> } else if (IS_ERR(page)) {
> ret = PTR_ERR(page);
> goto out;
> }
> +next_page:
> if (pages) {
> pages[i] = page;
> flush_anon_page(vma, page, start);
> flush_dcache_page(page);
I guess there's no harm that we now flush here, though it seems to me to be
superfluous, it's not a big deal I don't think.
> ctx.page_mask = 0;
> }
> -next_page:
> +
> page_increm = 1 + (~(start >> PAGE_SHIFT) & ctx.page_mask);
> if (page_increm > nr_pages)
> page_increm = nr_pages;
> --
> 2.40.1
>
Other than that, LGTM,
Reviewed-by: Lorenzo Stoakes <lstoakes@xxxxxxxxx>
