[PATCH io_uring for-review] io_uring/zcrx: convert to use netmem_desc

[PATCH io_uring for-review] io_uring/zcrx: convert to use netmem_desc

[Pavel Begunkov]

Convert zcrx to struct netmem_desc, and use struct net_iov::desc to
access its fields instead of struct net_iov inner union alises.
zcrx only directly reads niov->pp, so with this patch it doesn't depend
on the union anymore.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
 io_uring/zcrx.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/io_uring/zcrx.c b/io_uring/zcrx.c
index 723e4266b91f..966ed95e801d 100644
--- a/io_uring/zcrx.c
+++ b/io_uring/zcrx.c
@@ -693,12 +693,12 @@ static void io_zcrx_return_niov(struct net_iov *niov)
 {
 	netmem_ref netmem = net_iov_to_netmem(niov);
 
-	if (!niov->pp) {
+	if (!niov->desc.pp) {
 		/* copy fallback allocated niovs */
 		io_zcrx_return_niov_freelist(niov);
 		return;
 	}
-	page_pool_put_unrefed_netmem(niov->pp, netmem, -1, false);
+	page_pool_put_unrefed_netmem(niov->desc.pp, netmem, -1, false);
 }
 
 static void io_zcrx_scrub(struct io_zcrx_ifq *ifq)
@@ -800,7 +800,7 @@ static void io_zcrx_ring_refill(struct page_pool *pp,
 		if (!page_pool_unref_and_test(netmem))
 			continue;
 
-		if (unlikely(niov->pp != pp)) {
+		if (unlikely(niov->desc.pp != pp)) {
 			io_zcrx_return_niov(niov);
 			continue;
 		}
@@ -1136,13 +1136,15 @@ static int io_zcrx_recv_frag(struct io_kiocb *req, struct io_zcrx_ifq *ifq,
 			     const skb_frag_t *frag, int off, int len)
 {
 	struct net_iov *niov;
+	struct page_pool *pp;
 
 	if (unlikely(!skb_frag_is_net_iov(frag)))
 		return io_zcrx_copy_frag(req, ifq, frag, off, len);
 
 	niov = netmem_to_net_iov(frag->netmem);
-	if (!niov->pp || niov->pp->mp_ops != &io_uring_pp_zc_ops ||
-	    io_pp_to_ifq(niov->pp) != ifq)
+	pp = niov->desc.pp;
+
+	if (!pp || pp->mp_ops != &io_uring_pp_zc_ops || io_pp_to_ifq(pp) != ifq)
 		return -EFAULT;
 
 	if (!io_zcrx_queue_cqe(req, niov, ifq, off + skb_frag_off(frag), len))
-- 
2.49.0

Re: [PATCH io_uring for-review] io_uring/zcrx: convert to use netmem_desc

[Byungchul Park]

On Wed, Oct 08, 2025 at 02:12:54PM +0100, Pavel Begunkov wrote:
> Convert zcrx to struct netmem_desc, and use struct net_iov::desc to
> access its fields instead of struct net_iov inner union alises.
> zcrx only directly reads niov->pp, so with this patch it doesn't depend
> on the union anymore.

Looks clear enough and it's the necessary changes.

Reviewed-by: Byungchul Park <byungchul@sk.com>

	Byungchul

> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
> ---
>  io_uring/zcrx.c | 12 +++++++-----
>  1 file changed, 7 insertions(+), 5 deletions(-)
> 
> diff --git a/io_uring/zcrx.c b/io_uring/zcrx.c
> index 723e4266b91f..966ed95e801d 100644
> --- a/io_uring/zcrx.c
> +++ b/io_uring/zcrx.c
> @@ -693,12 +693,12 @@ static void io_zcrx_return_niov(struct net_iov *niov)
>  {
>         netmem_ref netmem = net_iov_to_netmem(niov);
> 
> -       if (!niov->pp) {
> +       if (!niov->desc.pp) {
>                 /* copy fallback allocated niovs */
>                 io_zcrx_return_niov_freelist(niov);
>                 return;
>         }
> -       page_pool_put_unrefed_netmem(niov->pp, netmem, -1, false);
> +       page_pool_put_unrefed_netmem(niov->desc.pp, netmem, -1, false);
>  }
> 
>  static void io_zcrx_scrub(struct io_zcrx_ifq *ifq)
> @@ -800,7 +800,7 @@ static void io_zcrx_ring_refill(struct page_pool *pp,
>                 if (!page_pool_unref_and_test(netmem))
>                         continue;
> 
> -               if (unlikely(niov->pp != pp)) {
> +               if (unlikely(niov->desc.pp != pp)) {
>                         io_zcrx_return_niov(niov);
>                         continue;
>                 }
> @@ -1136,13 +1136,15 @@ static int io_zcrx_recv_frag(struct io_kiocb *req, struct io_zcrx_ifq *ifq,
>                              const skb_frag_t *frag, int off, int len)
>  {
>         struct net_iov *niov;
> +       struct page_pool *pp;
> 
>         if (unlikely(!skb_frag_is_net_iov(frag)))
>                 return io_zcrx_copy_frag(req, ifq, frag, off, len);
> 
>         niov = netmem_to_net_iov(frag->netmem);
> -       if (!niov->pp || niov->pp->mp_ops != &io_uring_pp_zc_ops ||
> -           io_pp_to_ifq(niov->pp) != ifq)
> +       pp = niov->desc.pp;
> +
> +       if (!pp || pp->mp_ops != &io_uring_pp_zc_ops || io_pp_to_ifq(pp) != ifq)
>                 return -EFAULT;
> 
>         if (!io_zcrx_queue_cqe(req, niov, ifq, off + skb_frag_off(frag), len))
> --
> 2.49.0