| Message ID | 20190617073320.69015-1-lifei.shirley@bytedance.com |
|---|---|
| State | Changes Requested |
| Delegated to: | David Miller |
| Headers | show |
| Series | Fix tun: wake up waitqueues after IFF_UP is set | expand |
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. > > Signed-off-by: Fei Li <lifei.shirley@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 <jasowang@redhat.com)
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.shirley@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 <jasowang@redhat.com) >
Ok, thanks for the detail suggestion! :) On Mon, Jun 17, 2019 at 4:16 PM Jason Wang <jasowang@redhat.com> wrote: > > > 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.shirley@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 <jasowang@redhat.com) > >
Hi all, On Mon, Jun 17, 2019 at 5:32 PM 李菲 <lifei.shirley@bytedance.com> wrote: > > Ok, thanks for detail suggestion! :) > > On Mon, Jun 17, 2019 at 4:16 PM Jason Wang <jasowang@redhat.com> wrote: >> >> >> 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.shirley@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); Will remove the above unused struct in next version. Sorry for the negligence! Have a nice day, thanks Fei >> >> - 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 <jasowang@redhat.com) >> >
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; }
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. Signed-off-by: Fei Li <lifei.shirley@bytedance.com> --- drivers/net/tun.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-)