[PATCH v2 bpf-next] xsk: use __xsk_rcv_zc_safe for ZC multi-buffer Rx processing

[PATCH v2 bpf-next] xsk: use __xsk_rcv_zc_safe for ZC multi-buffer Rx processing

[Maciej Fijalkowski]

Commit f620af11c27b ("xsk: avoid double checking against rx queue being
full") addressed a case in copy mode, when working with multi-buffer
xdp_buff, where we were peeking onto XSK Rx queue twice, to find out if
there is a space to produce descriptors.

Adjust ZC path to follow the same principle.

Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
---
v2: route patch via bpf-next, not net-next
---
 net/xdp/xsk.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
index ef265e45810c..cdf93728fcba 100644
--- a/net/xdp/xsk.c
+++ b/net/xdp/xsk.c
@@ -196,13 +196,13 @@ static int xsk_rcv_zc(struct xdp_sock *xs, struct xdp_buff *xdp, u32 len)
 		goto err;
 	}
 
-	__xsk_rcv_zc(xs, xskb, len, contd);
+	__xsk_rcv_zc_safe(xs, xskb, len, contd);
 	xskb_list = &xskb->pool->xskb_list;
 	list_for_each_entry_safe(pos, tmp, xskb_list, list_node) {
 		if (list_is_singular(xskb_list))
 			contd = 0;
 		len = pos->xdp.data_end - pos->xdp.data;
-		__xsk_rcv_zc(xs, pos, len, contd);
+		__xsk_rcv_zc_safe(xs, pos, len, contd);
 		list_del_init(&pos->list_node);
 	}
 
-- 
2.43.0

Re: [PATCH v2 bpf-next] xsk: use __xsk_rcv_zc_safe for ZC multi-buffer Rx processing

[Stanislav Fomichev]

On 03/16, Maciej Fijalkowski wrote:
> Commit f620af11c27b ("xsk: avoid double checking against rx queue being
> full") addressed a case in copy mode, when working with multi-buffer
> xdp_buff, where we were peeking onto XSK Rx queue twice, to find out if
> there is a space to produce descriptors.
> 
> Adjust ZC path to follow the same principle.
> 
> Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
> ---
> v2: route patch via bpf-next, not net-next

Acked-by: Stanislav Fomichev <sdf@fomichev.me>

Re: [PATCH v2 bpf-next] xsk: use __xsk_rcv_zc_safe for ZC multi-buffer Rx processing

[Jakub Kicinski]

On Mon, 16 Mar 2026 15:05:57 +0100 Maciej Fijalkowski wrote:
> Commit f620af11c27b ("xsk: avoid double checking against rx queue being
> full") addressed a case in copy mode, when working with multi-buffer
> xdp_buff, where we were peeking onto XSK Rx queue twice, to find out if
> there is a space to produce descriptors.
> 
> Adjust ZC path to follow the same principle.

Acked-by: Jakub Kicinski <kuba@kernel.org>

Re: [PATCH v2 bpf-next] xsk: use __xsk_rcv_zc_safe for ZC multi-buffer Rx processing

[Jason Xing]

On Mon, Mar 16, 2026 at 10:14 PM Maciej Fijalkowski
<maciej.fijalkowski@intel.com> wrote:
>
> Commit f620af11c27b ("xsk: avoid double checking against rx queue being
> full") addressed a case in copy mode, when working with multi-buffer
> xdp_buff, where we were peeking onto XSK Rx queue twice, to find out if
> there is a space to produce descriptors.
>
> Adjust ZC path to follow the same principle.
>
> Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>

Reviewed-by: Jason Xing <kerneljasonxing@gmail.com>

Re: [PATCH v2 bpf-next] xsk: use __xsk_rcv_zc_safe for ZC multi-buffer Rx processing

[Alexei Starovoitov]

On Mon, Mar 16, 2026 at 5:12 PM Jakub Kicinski <kuba@kernel.org> wrote:
>
> On Mon, 16 Mar 2026 15:05:57 +0100 Maciej Fijalkowski wrote:
> > Commit f620af11c27b ("xsk: avoid double checking against rx queue being
> > full") addressed a case in copy mode, when working with multi-buffer
> > xdp_buff, where we were peeking onto XSK Rx queue twice, to find out if
> > there is a space to produce descriptors.
> >
> > Adjust ZC path to follow the same principle.
>
> Acked-by: Jakub Kicinski <kuba@kernel.org>

Do you guys need it in net-next in this merge window ?

We have nothing in bpf-next/net so far, so should be fine
to take this patch into net-next directly?

Martin, thoughts?

Re: [PATCH v2 bpf-next] xsk: use __xsk_rcv_zc_safe for ZC multi-buffer Rx processing

[Jakub Kicinski]

On Tue, 17 Mar 2026 08:09:08 -0700 Alexei Starovoitov wrote:
> On Mon, Mar 16, 2026 at 5:12 PM Jakub Kicinski <kuba@kernel.org> wrote:
> > On Mon, 16 Mar 2026 15:05:57 +0100 Maciej Fijalkowski wrote:  
> > > Commit f620af11c27b ("xsk: avoid double checking against rx queue being
> > > full") addressed a case in copy mode, when working with multi-buffer
> > > xdp_buff, where we were peeking onto XSK Rx queue twice, to find out if
> > > there is a space to produce descriptors.
> > >
> > > Adjust ZC path to follow the same principle.  
> >
> > Acked-by: Jakub Kicinski <kuba@kernel.org>  
> 
> Do you guys need it in net-next in this merge window ?
> 
> We have nothing in bpf-next/net so far, so should be fine
> to take this patch into net-next directly?

Somehow __xsk_rcv_zc_safe() landed in bpf-next/master f620af11c27b8ec9
So I think we have limited number of possible moves now :)

Re: [PATCH v2 bpf-next] xsk: use __xsk_rcv_zc_safe for ZC multi-buffer Rx processing

[Alexei Starovoitov]

On Tue, Mar 17, 2026 at 3:20 PM Jakub Kicinski <kuba@kernel.org> wrote:
>
> On Tue, 17 Mar 2026 08:09:08 -0700 Alexei Starovoitov wrote:
> > On Mon, Mar 16, 2026 at 5:12 PM Jakub Kicinski <kuba@kernel.org> wrote:
> > > On Mon, 16 Mar 2026 15:05:57 +0100 Maciej Fijalkowski wrote:
> > > > Commit f620af11c27b ("xsk: avoid double checking against rx queue being
> > > > full") addressed a case in copy mode, when working with multi-buffer
> > > > xdp_buff, where we were peeking onto XSK Rx queue twice, to find out if
> > > > there is a space to produce descriptors.
> > > >
> > > > Adjust ZC path to follow the same principle.
> > >
> > > Acked-by: Jakub Kicinski <kuba@kernel.org>
> >
> > Do you guys need it in net-next in this merge window ?
> >
> > We have nothing in bpf-next/net so far, so should be fine
> > to take this patch into net-next directly?
>
> Somehow __xsk_rcv_zc_safe() landed in bpf-next/master f620af11c27b8ec9
> So I think we have limited number of possible moves now :)

I wasn't paying attention. We can revert it in bpf-next and reapply
in net-next and probably route all future xsk patches to net/net-next ?
since it doesn't have much to do with bpf anymore.

Re: [PATCH v2 bpf-next] xsk: use __xsk_rcv_zc_safe for ZC multi-buffer Rx processing

[Jakub Kicinski]

On Tue, 17 Mar 2026 17:57:32 -0700 Alexei Starovoitov wrote:
> > > Do you guys need it in net-next in this merge window ?
> > >
> > > We have nothing in bpf-next/net so far, so should be fine
> > > to take this patch into net-next directly?  
> >
> > Somehow __xsk_rcv_zc_safe() landed in bpf-next/master f620af11c27b8ec9
> > So I think we have limited number of possible moves now :)  
> 
> I wasn't paying attention. We can revert it in bpf-next and reapply
> in net-next and probably route all future xsk patches to net/net-next ?
> since it doesn't have much to do with bpf anymore.

Maybe we should defer until the merge window and let it sit in Maciej's
local tree for now. It's a tiny optimization, Maciej can resend in the
next cycle.

Re: [PATCH v2 bpf-next] xsk: use __xsk_rcv_zc_safe for ZC multi-buffer Rx processing

[Alexei Starovoitov]

On Tue, Mar 17, 2026 at 6:29 PM Jakub Kicinski <kuba@kernel.org> wrote:
>
> On Tue, 17 Mar 2026 17:57:32 -0700 Alexei Starovoitov wrote:
> > > > Do you guys need it in net-next in this merge window ?
> > > >
> > > > We have nothing in bpf-next/net so far, so should be fine
> > > > to take this patch into net-next directly?
> > >
> > > Somehow __xsk_rcv_zc_safe() landed in bpf-next/master f620af11c27b8ec9
> > > So I think we have limited number of possible moves now :)
> >
> > I wasn't paying attention. We can revert it in bpf-next and reapply
> > in net-next and probably route all future xsk patches to net/net-next ?
> > since it doesn't have much to do with bpf anymore.
>
> Maybe we should defer until the merge window and let it sit in Maciej's
> local tree for now. It's a tiny optimization, Maciej can resend in the
> next cycle.

or I can apply it to bpf-next/master and we start taking xsk via net-next
after merge window?

Re: [PATCH v2 bpf-next] xsk: use __xsk_rcv_zc_safe for ZC multi-buffer Rx processing

[Jakub Kicinski]

On Tue, 17 Mar 2026 18:43:18 -0700 Alexei Starovoitov wrote:
> > > I wasn't paying attention. We can revert it in bpf-next and reapply
> > > in net-next and probably route all future xsk patches to net/net-next ?
> > > since it doesn't have much to do with bpf anymore.  
> >
> > Maybe we should defer until the merge window and let it sit in Maciej's
> > local tree for now. It's a tiny optimization, Maciej can resend in the
> > next cycle.  
> 
> or I can apply it to bpf-next/master and we start taking xsk via net-next
> after merge window?

SGTM

Re: [PATCH v2 bpf-next] xsk: use __xsk_rcv_zc_safe for ZC multi-buffer Rx processing

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to bpf/bpf-next.git (master)
by Alexei Starovoitov <ast@kernel.org>:

On Mon, 16 Mar 2026 15:05:57 +0100 you wrote:
> Commit f620af11c27b ("xsk: avoid double checking against rx queue being
> full") addressed a case in copy mode, when working with multi-buffer
> xdp_buff, where we were peeking onto XSK Rx queue twice, to find out if
> there is a space to produce descriptors.
> 
> Adjust ZC path to follow the same principle.
> 
> [...]

Here is the summary with links:
  - [v2,bpf-next] xsk: use __xsk_rcv_zc_safe for ZC multi-buffer Rx processing
    https://git.kernel.org/bpf/bpf-next/c/77378dabb50f

You are awesome, thank you!
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