Messages in this thread Patch in this message | | | From | Jason Wang <> | Subject | [PATCH net] tuntap: raise EPOLLOUT on device up | Date | Fri, 18 May 2018 21:00:43 +0800 |
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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 <hannes@stressinduktion.org> Cc: Eric Dumazet <edumazet@google.com> Fixes: 1bd4978a88ac2 ("tun: honor IFF_UP in tun_get_user()") Signed-off-by: Jason Wang <jasowang@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)) { + set_bit(SOCKWQ_ASYNC_NOSPACE, &tfile->socket.flags); return -EIO; + } if (!(tun->flags & IFF_NO_PI)) { if (len < sizeof(pi)) -- 2.7.4
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