Re: [PATCH v5 15/24] fs/io_uring: set FOLL_PIN via pin_user_pages()

From: Jan Kara
Date: Mon Nov 18 2019 - 07:01:34 EST


On Thu 14-11-19 21:53:31, John Hubbard wrote:
> Convert fs/io_uring to use the new pin_user_pages() call, which sets
> FOLL_PIN. Setting FOLL_PIN is now required for code that requires
> tracking of pinned pages, and therefore for any code that calls
> put_user_page().
>
> In partial anticipation of this work, the io_uring code was already
> calling put_user_page() instead of put_page(). Therefore, in order to
> convert from the get_user_pages()/put_page() model, to the
> pin_user_pages()/put_user_page() model, the only change required
> here is to change get_user_pages() to pin_user_pages().
>
> Signed-off-by: John Hubbard <jhubbard@xxxxxxxxxx>

Looks good to me. You can add:

Reviewed-by: Jan Kara <jack@xxxxxxx>

Honza

> ---
> fs/io_uring.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/io_uring.c b/fs/io_uring.c
> index f9a38998f2fc..cff64bd00db9 100644
> --- a/fs/io_uring.c
> +++ b/fs/io_uring.c
> @@ -3433,7 +3433,7 @@ static int io_sqe_buffer_register(struct io_ring_ctx *ctx, void __user *arg,
>
> ret = 0;
> down_read(&current->mm->mmap_sem);
> - pret = get_user_pages(ubuf, nr_pages,
> + pret = pin_user_pages(ubuf, nr_pages,
> FOLL_WRITE | FOLL_LONGTERM,
> pages, vmas);
> if (pret == nr_pages) {
> --
> 2.24.0
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR