Re: [PATCH net v4 2/2] vhost_net: fix tx queue stuck when sendmsg fails
From: Jason Wang <jasowang@redhat.com>
Date: 2020-12-24 03:12:07
Also in:
virtualization
On 2020/12/24 上午10:25, wangyunjian wrote:
From: Yunjian Wang <redacted> Currently the driver doesn't drop a packet which can't be sent by tun (e.g bad packet). In this case, the driver will always process the same packet lead to the tx queue stuck. To fix this issue: 1. in the case of persistent failure (e.g bad packet), the driver can skip this descriptor by ignoring the error. 2. in the case of transient failure (e.g -EAGAIN and -ENOMEM), the driver schedules the worker to try again.
I might be wrong but looking at alloc_skb_with_frags(), it returns -ENOBUFS actually: *errcode = -ENOBUFS; skb = alloc_skb(header_len, gfp_mask); if (!skb) return NULL; Thanks
quoted hunk ↗ jump to hunk
Fixes: 3a4d5c94e959 ("vhost_net: a kernel-level virtio server") Signed-off-by: Yunjian Wang <redacted> --- drivers/vhost/net.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-)diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index c8784dfafdd7..e76245daa7f6 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c@@ -827,14 +827,13 @@ static void handle_tx_copy(struct vhost_net *net, struct socket *sock) msg.msg_flags &= ~MSG_MORE; } - /* TODO: Check specific error and bomb out unless ENOBUFS? */ err = sock->ops->sendmsg(sock, &msg, len); - if (unlikely(err < 0)) { + if (unlikely(err == -EAGAIN || err == -ENOMEM)) { vhost_discard_vq_desc(vq, 1); vhost_net_enable_vq(net, vq); break; } - if (err != len) + if (err >= 0 && err != len) pr_debug("Truncated TX packet: len %d != %zd\n", err, len); done:@@ -922,7 +921,6 @@ static void handle_tx_zerocopy(struct vhost_net *net, struct socket *sock) msg.msg_flags &= ~MSG_MORE; } - /* TODO: Check specific error and bomb out unless ENOBUFS? */ err = sock->ops->sendmsg(sock, &msg, len); if (unlikely(err < 0)) { if (zcopy_used) {@@ -931,11 +929,13 @@ static void handle_tx_zerocopy(struct vhost_net *net, struct socket *sock) nvq->upend_idx = ((unsigned)nvq->upend_idx - 1) % UIO_MAXIOV; } - vhost_discard_vq_desc(vq, 1); - vhost_net_enable_vq(net, vq); - break; + if (err == -EAGAIN || err == -ENOMEM) { + vhost_discard_vq_desc(vq, 1); + vhost_net_enable_vq(net, vq); + break; + } } - if (err != len) + if (err >= 0 && err != len) pr_debug("Truncated TX packet: " " len %d != %zd\n", err, len); if (!zcopy_used)