On 2018年05月18日 22:46, Michael S. Tsirkin wrote:
On Fri, May 18, 2018 at 10:11:54PM +0800, Jason Wang wrote:
On 2018年05月18日 22:06, Michael S. Tsirkin wrote:
On Fri, May 18, 2018 at 10:00:31PM +0800, Jason Wang wrote:
On 2018年05月18日 21:26, Jason Wang wrote:
On 2018年05月18日 21:13, Michael S. Tsirkin wrote:
On Fri, May 18, 2018 at 09:00:43PM +0800, Jason Wang wrote:
We return -EIO on device down but can not raise EPOLLOUT after it was
up. This may confuse user like vhost which expects tuntap to raise
EPOLLOUT to re-enable its TX routine after tuntap is down. This could
be easily reproduced by transmitting packets from VM while down and up
the tap device. Fixing this by set SOCKWQ_ASYNC_NOSPACE on -EIO.
Cc: Hannes Frederic Sowa <han...@stressinduktion.org>
Cc: Eric Dumazet <eduma...@google.com>
Fixes: 1bd4978a88ac2 ("tun: honor IFF_UP in tun_get_user()")
Signed-off-by: Jason Wang <jasow...@redhat.com>
---
drivers/net/tun.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index d45ac37..1b29761 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -1734,8 +1734,10 @@ static ssize_t tun_get_user(struct
tun_struct *tun, struct tun_file *tfile,
int skb_xdp = 1;
bool frags = tun_napi_frags_enabled(tun);
- if (!(tun->dev->flags & IFF_UP))
+ if (!(tun->dev->flags & IFF_UP)) {
Isn't this racy? What if flag is cleared at this point?
I think you mean "set at this point"? Then yes, so we probably need to
set the bit during tun_net_close().
Thanks
Looks no need, vhost will poll socket after it see EIO. So we are ok here?
Thanks
In fact I don't even understand why does this help any longer.
We disable tx polling and only enable it on demand for a better rx
performance. You may want to have a look at :
commit feb8892cb441c742d4220cf7ced001e7fa070731
Author: Jason Wang <jasow...@redhat.com>
Date: Mon Nov 13 11:45:34 2017 +0800
vhost_net: conditionally enable tx polling
Thanks
Question is, what looks at SOCKWQ_ASYNC_NOSPACE.
I think it's tested when packet is transmitted,
but there is no guarantee here any packet will
ever be transmitted.
Well, actually, I do plan to disable vq polling from the beginning. But
looks like you do not want this:
See https://patchwork.kernel.org/patch/10034025/
Thanks
