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Mon, 12 Oct 2026 15:02:53 -0700 (PDT) Date: Mon, 12 Oct 2026 15:02:50 -0700 From: Bobby Eshleman To: Jia Jia Cc: stefanha@redhat.com, sgarzare@redhat.com, netdev@vger.kernel.org, virtualization@lists.linux.dev, kvm@vger.kernel.org, mst@redhat.com, jasowangio@gmail.com, eperezma@redhat.com, xuanzhuo@linux.alibaba.com, davem@davemloft.net, edumazet@kernel.org, kuba@kernel.org, pabeni@redhat.com, horms@kernel.org, linux-kernel@vger.kernel.org, bpf@vger.kernel.org Subject: Re: [PATCH net-next v2 1/5] vsock/virtio: split socket lookup from locked RX processing Message-ID: References: <20261010142247.99223-1-physicalmtea@gmail.com> <20261010142247.99223-2-physicalmtea@gmail.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261010142247.99223-2-physicalmtea@gmail.com> On Sat, Oct 10, 2026 at 10:22:43PM +0800, Jia Jia wrote: > Split virtio_transport_recv_pkt() so socket lookup is separate from the > receive state machine that runs under the socket lock. > > Keep virtio_transport_recv_pkt() on its existing per-packet locking path. > Pass the source and destination addresses used for lookup to the locked > receive path so they are decoded only once. > > Pass the network namespace and decoded address tuple through a packet > context to the locked receive path. > > Preserve source validation and failure handling. Keep the lookup reference > separate from the skb owner reference so the locked receive path can manage > the two lifetimes independently. > > Signed-off-by: Jia Jia > --- > net/vmw_vsock/virtio_transport_common.c | 139 ++++++++++++++++-------- > 1 file changed, 96 insertions(+), 43 deletions(-) > [...] > +/* > + * The caller holds sk's socket lock and must free skb if this returns true. > + */ > +static bool > +virtio_transport_recv_pkt_locked(struct virtio_transport *t, > + struct sk_buff *skb, struct sock *sk, > + const struct virtio_transport_rx_pkt_ctx *ctx) > +{ > + const struct sockaddr_vm *src = ctx->src; > + const struct sockaddr_vm *dst = ctx->dst; > + struct vsock_sock *vsk = vsock_sk(sk); > + struct net *net = ctx->net; > + bool space_available; > > - /* Check if sk has been closed or assigned to another transport before > - * lock_sock (note: listener sockets are not assigned to any transport) > + /* Check after acquiring the socket lock. Listener sockets accept packets > + * from any source and are not assigned to a transport. > */ > if (sock_flag(sk, SOCK_DONE) || > (sk->sk_state != TCP_LISTEN && > - !vsock_check_source(vsk, &t->transport, &src))) { > + !vsock_check_source(vsk, &t->transport, src))) { > (void)virtio_transport_reset_no_sock(t, skb, net); > - release_sock(sk); > - sock_put(sk); > - goto free_pkt; > + return true; > } > > space_available = virtio_transport_space_update(sk, skb); > > /* Update CID in case it has changed after a transport reset event */ > if (vsk->local_addr.svm_cid != VMADDR_CID_ANY) > - vsk->local_addr.svm_cid = dst.svm_cid; > + vsk->local_addr.svm_cid = dst->svm_cid; > > if (space_available) > sk->sk_write_space(sk); > @@ -1875,12 +1891,49 @@ void virtio_transport_recv_pkt(struct virtio_transport *t, > break; > } > > + return false; > +} > + > +/* We are under the virtio-vsock's vsock->rx_lock or vhost-vsock's vq->mutex > + * lock. > + */ > +void virtio_transport_recv_pkt(struct virtio_transport *t, > + struct sk_buff *skb, struct net *net) > +{ > + struct virtio_transport_rx_pkt_ctx ctx; > + struct sockaddr_vm src, dst; > + struct sock *sk; > + bool free_pkt; > + > + virtio_transport_recv_pkt_init_addrs(skb, &src, &dst); > + virtio_transport_trace_recv_pkt(skb, &src, &dst); > + > + sk = virtio_transport_recv_pkt_find_socket(skb, &src, &dst, net); > + if (!sk) { > + (void)virtio_transport_reset_no_sock(t, skb, net); > + goto free_pkt; > + } > + > + if (!skb_set_owner_sk_safe(skb, sk)) { > + WARN_ONCE(1, "receiving vsock socket has sk_refcnt == 0\n"); > + goto free_pkt; > + } > + > + lock_sock(sk); > + ctx = (struct virtio_transport_rx_pkt_ctx) { > + .net = net, > + .src = &src, > + .dst = &dst, > + }; > + free_pkt = virtio_transport_recv_pkt_locked(t, skb, sk, &ctx); At this point the socket lookup succeeded with src/dst/net, why not just pass sk which already has all of them? Best, Bobby