netdev - Re: [net-next v1 01/16] net: page_pool: factor out releasing DMA from releasing the page

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date: Tue, 12 Dec 2023 10:11:50 +0200
From: Ilias Apalodimas <ilias.apalodimas@...aro.org>
To: Mina Almasry <almasrymina@...gle.com>
Cc: Shailend Chand <shailend@...gle.com>, netdev@...r.kernel.org, 
	linux-kernel@...r.kernel.org, linux-doc@...r.kernel.org, 
	linux-arch@...r.kernel.org, linux-kselftest@...r.kernel.org, 
	bpf@...r.kernel.org, linux-media@...r.kernel.org, 
	dri-devel@...ts.freedesktop.org, "David S. Miller" <davem@...emloft.net>, 
	Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>, 
	Jonathan Corbet <corbet@....net>, Jeroen de Borst <jeroendb@...gle.com>, 
	Praveen Kaligineedi <pkaligineedi@...gle.com>, Jesper Dangaard Brouer <hawk@...nel.org>, Arnd Bergmann <arnd@...db.de>, 
	David Ahern <dsahern@...nel.org>, Willem de Bruijn <willemdebruijn.kernel@...il.com>, 
	Shuah Khan <shuah@...nel.org>, Sumit Semwal <sumit.semwal@...aro.org>, 
	Christian König <christian.koenig@....com>, 
	Yunsheng Lin <linyunsheng@...wei.com>, Harshitha Ramamurthy <hramamurthy@...gle.com>, 
	Shakeel Butt <shakeelb@...gle.com>
Subject: Re: [net-next v1 01/16] net: page_pool: factor out releasing DMA from
 releasing the page

On Fri, 8 Dec 2023 at 02:52, Mina Almasry <almasrymina@...gle.com> wrote:
>
> From: Jakub Kicinski <kuba@...nel.org>
>
> Releasing the DMA mapping will be useful for other types
> of pages, so factor it out. Make sure compiler inlines it,
> to avoid any regressions.
>
> Signed-off-by: Jakub Kicinski <kuba@...nel.org>
> Signed-off-by: Mina Almasry <almasrymina@...gle.com>
>
> ---
>
> This is implemented by Jakub in his RFC:
>
> https://lore.kernel.org/netdev/f8270765-a27b-6ccf-33ea-cda097168d79@redhat.com/T/
>
> I take no credit for the idea or implementation. This is a critical
> dependency of device memory TCP and thus I'm pulling it into this series
> to make it revewable and mergable.
>
> ---
>  net/core/page_pool.c | 25 ++++++++++++++++---------
>  1 file changed, 16 insertions(+), 9 deletions(-)
>
> diff --git a/net/core/page_pool.c b/net/core/page_pool.c
> index c2e7c9a6efbe..ca1b3b65c9b5 100644
> --- a/net/core/page_pool.c
> +++ b/net/core/page_pool.c
> @@ -548,21 +548,16 @@ s32 page_pool_inflight(const struct page_pool *pool, bool strict)
>         return inflight;
>  }
>
> -/* Disconnects a page (from a page_pool).  API users can have a need
> - * to disconnect a page (from a page_pool), to allow it to be used as
> - * a regular page (that will eventually be returned to the normal
> - * page-allocator via put_page).
> - */
> -static void page_pool_return_page(struct page_pool *pool, struct page *page)
> +static __always_inline
> +void __page_pool_release_page_dma(struct page_pool *pool, struct page *page)
>  {
>         dma_addr_t dma;
> -       int count;
>
>         if (!(pool->p.flags & PP_FLAG_DMA_MAP))
>                 /* Always account for inflight pages, even if we didn't
>                  * map them
>                  */
> -               goto skip_dma_unmap;
> +               return;
>
>         dma = page_pool_get_dma_addr(page);
>
> @@ -571,7 +566,19 @@ static void page_pool_return_page(struct page_pool *pool, struct page *page)
>                              PAGE_SIZE << pool->p.order, pool->p.dma_dir,
>                              DMA_ATTR_SKIP_CPU_SYNC | DMA_ATTR_WEAK_ORDERING);
>         page_pool_set_dma_addr(page, 0);
> -skip_dma_unmap:
> +}
> +
> +/* Disconnects a page (from a page_pool).  API users can have a need
> + * to disconnect a page (from a page_pool), to allow it to be used as
> + * a regular page (that will eventually be returned to the normal
> + * page-allocator via put_page).
> + */
> +void page_pool_return_page(struct page_pool *pool, struct page *page)
> +{
> +       int count;
> +
> +       __page_pool_release_page_dma(pool, page);
> +
>         page_pool_clear_pp_info(page);
>
>         /* This may be the last page returned, releasing the pool, so
> --
> 2.43.0.472.g3155946c3a-goog
>

Reviewed-by: Ilias Apalodimas <ilias.apalodimas@...aro.org>