From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [PATCH v4 3/5] vsock/virtio: fix locking in virtio_transport_inc_tx_pkt() Date: Wed, 17 Jul 2019 10:51:47 -0400 Message-ID: <20190717105056-mutt-send-email-mst__27436.2091485941$1563375128$gmane$org@kernel.org> References: <20190717113030.163499-1-sgarzare@redhat.com> <20190717113030.163499-4-sgarzare@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20190717113030.163499-4-sgarzare@redhat.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: Stefano Garzarella Cc: kvm@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, Stefan Hajnoczi , "David S. Miller" List-Id: virtualization@lists.linuxfoundation.org On Wed, Jul 17, 2019 at 01:30:28PM +0200, Stefano Garzarella wrote: > fwd_cnt and last_fwd_cnt are protected by rx_lock, so we should use > the same spinlock also if we are in the TX path. > > Move also buf_alloc under the same lock. > > Signed-off-by: Stefano Garzarella Wait a second is this a bugfix? If it's used under the wrong lock won't values get corrupted? Won't traffic then stall or more data get to sent than credits? > --- > include/linux/virtio_vsock.h | 2 +- > net/vmw_vsock/virtio_transport_common.c | 4 ++-- > 2 files changed, 3 insertions(+), 3 deletions(-) > > diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h > index 49fc9d20bc43..4c7781f4b29b 100644 > --- a/include/linux/virtio_vsock.h > +++ b/include/linux/virtio_vsock.h > @@ -35,7 +35,6 @@ struct virtio_vsock_sock { > > /* Protected by tx_lock */ > u32 tx_cnt; > - u32 buf_alloc; > u32 peer_fwd_cnt; > u32 peer_buf_alloc; > > @@ -43,6 +42,7 @@ struct virtio_vsock_sock { > u32 fwd_cnt; > u32 last_fwd_cnt; > u32 rx_bytes; > + u32 buf_alloc; > struct list_head rx_queue; > }; > > diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c > index a85559d4d974..34a2b42313b7 100644 > --- a/net/vmw_vsock/virtio_transport_common.c > +++ b/net/vmw_vsock/virtio_transport_common.c > @@ -210,11 +210,11 @@ static void virtio_transport_dec_rx_pkt(struct virtio_vsock_sock *vvs, > > void virtio_transport_inc_tx_pkt(struct virtio_vsock_sock *vvs, struct virtio_vsock_pkt *pkt) > { > - spin_lock_bh(&vvs->tx_lock); > + spin_lock_bh(&vvs->rx_lock); > vvs->last_fwd_cnt = vvs->fwd_cnt; > pkt->hdr.fwd_cnt = cpu_to_le32(vvs->fwd_cnt); > pkt->hdr.buf_alloc = cpu_to_le32(vvs->buf_alloc); > - spin_unlock_bh(&vvs->tx_lock); > + spin_unlock_bh(&vvs->rx_lock); > } > EXPORT_SYMBOL_GPL(virtio_transport_inc_tx_pkt); > > -- > 2.20.1