On 2019/6/17 下午4:10, Jason Wang wrote:
On 2019/6/17 下午3:33, Fei Li wrote:
Currently after setting tap0 link up, the tun code wakes tx/rx waited
queues up in tun_net_open() when .ndo_open() is called, however the
IFF_UP flag has not been set yet. If there's already a wait queue, it
would fail to transmit when checking the IFF_UP flag in tun_sendmsg().
Then the saving vhost_poll_start() will add the wq into wqh until it
is waken up again. Although this works when IFF_UP flag has been set
when tun_chr_poll detects; this is not true if IFF_UP flag has not
been set at that time. Sadly the latter case is a fatal error, as
the wq will never be waken up in future unless later manually
setting link up on purpose.
Fix this by moving the wakeup process into the NETDEV_UP event
notifying process, this makes sure IFF_UP has been set before all
waited queues been waken up.
Btw, the title needs some tweak. E.g you need use "net" as prefix since
it's a fix for net.git and "Fix" could be removed like:
[PATCH net] tun: wake up waitqueues after IFF_UP is set.
Thanks
Signed-off-by: Fei Li <lifei.shir...@bytedance.com>
---
drivers/net/tun.c | 17 +++++++++--------
1 file changed, 9 insertions(+), 8 deletions(-)
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index c452d6d831dd..a3c9cab5a4d0 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -1015,17 +1015,9 @@ static void tun_net_uninit(struct net_device
*dev)
static int tun_net_open(struct net_device *dev)
{
struct tun_struct *tun = netdev_priv(dev);
- int i;
netif_tx_start_all_queues(dev);
- for (i = 0; i < tun->numqueues; i++) {
- struct tun_file *tfile;
-
- tfile = rtnl_dereference(tun->tfiles[i]);
- tfile->socket.sk->sk_write_space(tfile->socket.sk);
- }
-
return 0;
}
@@ -3634,6 +3626,7 @@ static int tun_device_event(struct
notifier_block *unused,
{
struct net_device *dev = netdev_notifier_info_to_dev(ptr);
struct tun_struct *tun = netdev_priv(dev);
+ int i;
if (dev->rtnl_link_ops != &tun_link_ops)
return NOTIFY_DONE;
@@ -3643,6 +3636,14 @@ static int tun_device_event(struct
notifier_block *unused,
if (tun_queue_resize(tun))
return NOTIFY_BAD;
break;
+ case NETDEV_UP:
+ for (i = 0; i < tun->numqueues; i++) {
+ struct tun_file *tfile;
+
+ tfile = rtnl_dereference(tun->tfiles[i]);
+ tfile->socket.sk->sk_write_space(tfile->socket.sk);
+ }
+ break;
default:
break;
}
Acked-by: Jason Wang <jasow...@redhat.com)
