From: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
To: Richard Gobert <richardbgobert@gmail.com>,
davem@davemloft.net, edumazet@google.com, kuba@kernel.org,
pabeni@redhat.com, dsahern@kernel.org,
willemdebruijn.kernel@gmail.com, alobakin@pm.me,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: Richard Gobert <richardbgobert@gmail.com>
Subject: Re: [PATCH net v3 2/2] net: gro: add flush check in udp_gro_receive_segment
Date: Wed, 24 Apr 2024 22:45:55 -0400 [thread overview]
Message-ID: <6629c3e399f65_1bd6b029423@willemb.c.googlers.com.notmuch> (raw)
In-Reply-To: <20240424163045.123528-3-richardbgobert@gmail.com>
Richard Gobert wrote:
> GRO-GSO path is supposed to be transparent and as such L3 flush checks are
> relevant to all UDP flows merging in GRO. This patch uses the same logic
> and code from tcp_gro_receive, terminating merge if flush is non zero.
>
> Fixes: 36707061d6ba ("udp: allow forwarding of plain (non-fraglisted) UDP GRO packets")
Should this be
Fixes: e20cf8d3f1f7 ("udp: implement GRO for plain UDP sockets.")
> net/ipv4/udp_offload.c | 12 +++++++++++-
> 1 file changed, 11 insertions(+), 1 deletion(-)
>
> diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c
> index fd29d21d579c..8721fe5beca2 100644
> --- a/net/ipv4/udp_offload.c
> +++ b/net/ipv4/udp_offload.c
> @@ -471,6 +471,7 @@ static struct sk_buff *udp_gro_receive_segment(struct list_head *head,
> struct sk_buff *p;
> unsigned int ulen;
> int ret = 0;
> + int flush;
>
> /* requires non zero csum, for symmetry with GSO */
> if (!uh->check) {
> @@ -504,13 +505,22 @@ static struct sk_buff *udp_gro_receive_segment(struct list_head *head,
> return p;
> }
>
> + flush = NAPI_GRO_CB(p)->flush;
> +
> + if (NAPI_GRO_CB(p)->flush_id != 1 ||
> + NAPI_GRO_CB(p)->count != 1 ||
> + !NAPI_GRO_CB(p)->is_atomic)
> + flush |= NAPI_GRO_CB(p)->flush_id;
> + else
> + NAPI_GRO_CB(p)->is_atomic = false;
> +
> /* Terminate the flow on len mismatch or if it grow "too much".
> * Under small packet flood GRO count could elsewhere grow a lot
> * leading to excessive truesize values.
> * On len mismatch merge the first packet shorter than gso_size,
> * otherwise complete the GRO packet.
> */
> - if (ulen > ntohs(uh2->len)) {
> + if (ulen > ntohs(uh2->len) || flush) {
> pp = p;
I suppose this branch already could immediately return p. And avoid
a level of indentation below. But agreed to not change that in this
bug fix.
prev parent reply other threads:[~2024-04-25 2:45 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-24 16:30 [PATCH net v3 0/2] net: gro: add flush/flush_id checks and fix wrong offset in udp Richard Gobert
2024-04-24 16:30 ` [PATCH net v3 1/2] net: gro: fix udp bad offset in socket lookup by adding {inner_}network_offset to napi_gro_cb Richard Gobert
2024-04-25 2:15 ` Willem de Bruijn
2024-04-25 11:59 ` Richard Gobert
2024-04-25 13:56 ` Willem de Bruijn
2024-04-24 16:30 ` [PATCH net v3 2/2] net: gro: add flush check in udp_gro_receive_segment Richard Gobert
2024-04-25 2:45 ` Willem de Bruijn [this message]
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