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bh=k0kdmiuUBm84KdFcT4b+ESMMTH4N7NEBgM35wYTC9cY=; b=IBeYZoM3JkkF/fveKnQWVgdrYA51ufEQ9IDXCv+DVnFzLIppy8JrH5pctXPO6WcbVg L8yBGL4V4Mdlm6SVb0CI74YaFJ2H2O4lq73h7CciM/ARZDIup2SEgXncV6HIEhur7QUk J1c/h5NJGQDPLkNbE68eSqlepyAWR3dPP6UGc5NWJ2FVKIbLhLtJqJjCIttNxuAFKaK5 qDaNNIHKlk6BSnBSf0CSXskLr9mtXliTIc3oDLVBF49Q0rGZqvtce+gtYz/HQhuchhcb +aIeGdXSIidgUs7pKmI19vu3vJhGGZJM+WVKqRZqB2cqBTorCNxdEVk06vVkaK7og8Xp QWMQ== X-Gm-Message-State: AOAM532raCMjLMcjXfgTqpzFOd0tgXdbFe9+L7rp7Uexe97zQ65vi44K ItuGXBcR4LgxzNoHYebTjzJejOhyvqvjJHQgJde1kjwwnhE= X-Google-Smtp-Source: ABdhPJyTcgeyk0VS7ZQDjEGJu3CH3SgAzBAeiXTwopEcu92HcP34ctHrmLx8sGTxQQSAk4URpOXpoojF4Ew2E5TSfR0= X-Received: by 2002:aa7:9981:0:b029:1d4:2f7b:e0d with SMTP id k1-20020aa799810000b02901d42f7b0e0dmr20706429pfh.10.1612834533361; Mon, 08 Feb 2021 17:35:33 -0800 (PST) MIME-Version: 1.0 References: <20210203041636.38555-1-xiyou.wangcong@gmail.com> <20210203041636.38555-9-xiyou.wangcong@gmail.com> In-Reply-To: From: Cong Wang Date: Mon, 8 Feb 2021 17:35:22 -0800 Message-ID: Subject: Re: [Patch bpf-next 08/19] udp: implement ->read_sock() for sockmap To: Lorenz Bauer Cc: Networking , bpf , duanxiongchun@bytedance.com, Dongdong Wang , jiang.wang@bytedance.com, Cong Wang , John Fastabend , Daniel Borkmann , Jakub Sitnicki Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Mon, Feb 8, 2021 at 1:48 AM Lorenz Bauer wrote: > > On Wed, 3 Feb 2021 at 04:17, Cong Wang wrote: > > > > From: Cong Wang > > > > Cc: John Fastabend > > Cc: Daniel Borkmann > > Cc: Jakub Sitnicki > > Cc: Lorenz Bauer > > Signed-off-by: Cong Wang > > --- > > include/net/udp.h | 2 ++ > > net/ipv4/af_inet.c | 1 + > > net/ipv4/udp.c | 34 ++++++++++++++++++++++++++++++++++ > > 3 files changed, 37 insertions(+) > > > > diff --git a/include/net/udp.h b/include/net/udp.h > > index 13f9354dbd3e..b6b75cabf4e4 100644 > > --- a/include/net/udp.h > > +++ b/include/net/udp.h > > @@ -327,6 +327,8 @@ struct sock *__udp6_lib_lookup(struct net *net, > > struct sk_buff *skb); > > struct sock *udp6_lib_lookup_skb(const struct sk_buff *skb, > > __be16 sport, __be16 dport); > > +int udp_read_sock(struct sock *sk, read_descriptor_t *desc, > > + sk_read_actor_t recv_actor); > > > > /* UDP uses skb->dev_scratch to cache as much information as possible and avoid > > * possibly multiple cache miss on dequeue() > > diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c > > index d184d9379a92..4a4c6d3d2786 100644 > > --- a/net/ipv4/af_inet.c > > +++ b/net/ipv4/af_inet.c > > @@ -1072,6 +1072,7 @@ const struct proto_ops inet_dgram_ops = { > > .getsockopt = sock_common_getsockopt, > > .sendmsg = inet_sendmsg, > > .sendmsg_locked = udp_sendmsg_locked, > > + .read_sock = udp_read_sock, > > .recvmsg = inet_recvmsg, > > .mmap = sock_no_mmap, > > .sendpage = inet_sendpage, > > diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c > > index 635e1e8b2968..6dffbcec0b51 100644 > > --- a/net/ipv4/udp.c > > +++ b/net/ipv4/udp.c > > @@ -1792,6 +1792,40 @@ struct sk_buff *__skb_recv_udp(struct sock *sk, unsigned int flags, > > } > > EXPORT_SYMBOL(__skb_recv_udp); > > > > +int udp_read_sock(struct sock *sk, read_descriptor_t *desc, > > + sk_read_actor_t recv_actor) > > +{ > > + struct sk_buff *skb; > > + int copied = 0, err; > > + > > + while (1) { > > + int offset = 0; > > + > > + skb = __skb_recv_udp(sk, 0, 1, &offset, &err); > > Seems like err isn't used outside of the loop, is that on purpose? If > yes, how about moving the declaration of err to be with offset. Maybe > rename to ignored? It should be moved inside the loop. > > > + if (!skb) > > + break; > > + if (offset < skb->len) { > > + int used; > > + size_t len; > > + > > + len = skb->len - offset; > > + used = recv_actor(desc, skb, offset, len); > > + if (used <= 0) { > > + if (!copied) > > + copied = used; > > + break; > > + } else if (used <= len) { > > In which case can used be > len? I think in splice() case it could return a larger value than 'len', but UDP does not support splice() even after this patchset. I can change it to 'else', or just leave it as it is, in case we will add splice() support in the future. Thanks.