2020-02-28 15:43:52

by Claudio Imbrenda

Subject: [RFC v1 1/2] fixup for 9947ea2c1e608e32669d5caeb67b3e3fba3309e8 "mm/gup: track FOLL_PIN pages"

in case pin fails, we need to unpin, just a put_page will not be enough

Signed-off-by: Claudio Imbrenda <[email protected]>
---
mm/gup.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/mm/gup.c b/mm/gup.c
index f589299b0d4a..0b9a806898f3 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -2134,7 +2134,10 @@ static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end,
goto pte_unmap;

if (unlikely(pte_val(pte) != pte_val(*ptep))) {
- put_page(head);
+ if (flags & FOLL_GET)
+ put_page(head);
+ else if (flags & FOLL_PIN)
+ unpin_user_page(head);
goto pte_unmap;
}

--
2.24.1

2020-02-28 15:47:01

by Claudio Imbrenda

Subject: Re: [RFC v1 1/2] fixup for 9947ea2c1e608e32669d5caeb67b3e3fba3309e8 "mm/gup: track FOLL_PIN pages"

sorry, this one was a mistake, please ignore


On Fri, 28 Feb 2020 16:43:20 +0100
Claudio Imbrenda <[email protected]> wrote:

> in case pin fails, we need to unpin, just a put_page will not be
> enough
>
> Signed-off-by: Claudio Imbrenda <[email protected]>
> ---
> mm/gup.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/mm/gup.c b/mm/gup.c
> index f589299b0d4a..0b9a806898f3 100644
> --- a/mm/gup.c
> +++ b/mm/gup.c
> @@ -2134,7 +2134,10 @@ static int gup_pte_range(pmd_t pmd, unsigned
> long addr, unsigned long end, goto pte_unmap;
>
> if (unlikely(pte_val(pte) != pte_val(*ptep))) {
> - put_page(head);
> + if (flags & FOLL_GET)
> + put_page(head);
> + else if (flags & FOLL_PIN)
> + unpin_user_page(head);
> goto pte_unmap;
> }
>