| Submitter | Jason Wang |
|---|---|
| Date | Jan. 15, 2013, 10:28 a.m. |
| Message ID | <1358245726-16250-4-git-send-email-jasowang@redhat.com> |
| Download | mbox | patch |
| Permalink | /patch/212076/ |
| State | Changes Requested |
| Delegated to: | David Miller |
| Headers | show |
Comments
On Tue, Jan 15, 2013 at 06:28:46PM +0800, Jason Wang wrote: > We forbid polling, writing and reading when the file were detached, this may > complex the user in several cases: > > - when guest pass some buffers to vhost/qemu and then disable some queues, > vhost/qemu needs to to its own cleanup which is complex. We can do this simply > by allowing a user can still write to an disabled queue to handle this. And > user can still do read but just nothing returned. > - align the polling behavior with macvtap which never fails when the queue is > created. this can simplify the polling errors handling of its user (e.g vhost) > > Signed-off-by: Jason Wang <jasowang@redhat.com> > --- > drivers/net/tun.c | 18 +++++++++++------- > 1 files changed, 11 insertions(+), 7 deletions(-) > > diff --git a/drivers/net/tun.c b/drivers/net/tun.c > index af372d0..eb68937 100644 > --- a/drivers/net/tun.c > +++ b/drivers/net/tun.c > @@ -307,7 +307,7 @@ static void tun_flow_update(struct tun_struct *tun, u32 rxhash, > > rcu_read_lock(); > > - if (tun->numqueues == 1) > + if (tun->numqueues == 1 || queue_index >= tun->numqueues) > goto unlock; > > e = tun_flow_find(head, rxhash); Hmm I don't understand - does something ensure that queue_index is > numqueues if the queue is disabled? Can we check tun->disabled and skip tun_flow_update completely? We might need to switch to rcu_assign for tun->disabled for this but otherwise it looks easy. > @@ -406,21 +406,21 @@ static void __tun_detach(struct tun_file *tfile, bool clean) > > tun = rtnl_dereference(tfile->tun); > > - if (tun) { > + if (tun && !tfile->detached) { > u16 index = tfile->queue_index; > BUG_ON(index >= tun->numqueues); > dev = tun->dev; > > rcu_assign_pointer(tun->tfiles[index], > tun->tfiles[tun->numqueues - 1]); > - rcu_assign_pointer(tfile->tun, NULL); > ntfile = rtnl_dereference(tun->tfiles[index]); > ntfile->queue_index = index; > > --tun->numqueues; > - if (clean) > + if (clean) { > + rcu_assign_pointer(tfile->tun, NULL); > sock_put(&tfile->sk); > - else > + } else > tun_disable_queue(tun, tfile); > > synchronize_net(); > @@ -465,6 +465,10 @@ static void tun_detach_all(struct net_device *dev) > rcu_assign_pointer(tfile->tun, NULL); > --tun->numqueues; > } > + list_for_each_entry(tfile, &tun->disabled, next) { > + wake_up_all(&tfile->wq.wait); > + rcu_assign_pointer(tfile->tun, NULL); > + } > BUG_ON(tun->numqueues != 0); > > synchronize_net(); > @@ -491,7 +495,7 @@ static int tun_attach(struct tun_struct *tun, struct file *file) > int err; > > err = -EINVAL; > - if (rtnl_dereference(tfile->tun)) > + if (rtnl_dereference(tfile->tun) && !tfile->detached) > goto out; > > err = -EBUSY; > @@ -1795,7 +1799,7 @@ static int tun_set_queue(struct file *file, struct ifreq *ifr) > ret = tun_attach(tun, file); > } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) { > tun = rtnl_dereference(tfile->tun); > - if (!tun || !(tun->flags & TUN_TAP_MQ)) > + if (!tun || !(tun->flags & TUN_TAP_MQ) || tfile->detached) > ret = -EINVAL; > else > __tun_detach(tfile, false); > -- > 1.7.1 -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tuesday, January 15, 2013 06:48:08 PM Michael S. Tsirkin wrote: > On Tue, Jan 15, 2013 at 06:28:46PM +0800, Jason Wang wrote: > > We forbid polling, writing and reading when the file were detached, this > > may complex the user in several cases: > > > > - when guest pass some buffers to vhost/qemu and then disable some queues, > > > > vhost/qemu needs to to its own cleanup which is complex. We can do this > > simply by allowing a user can still write to an disabled queue to > > handle this. And user can still do read but just nothing returned. > > > > - align the polling behavior with macvtap which never fails when the queue > > is> > > created. this can simplify the polling errors handling of its user (e.g > > vhost)> > > Signed-off-by: Jason Wang <jasowang@redhat.com> > > --- > > > > drivers/net/tun.c | 18 +++++++++++------- > > 1 files changed, 11 insertions(+), 7 deletions(-) > > > > diff --git a/drivers/net/tun.c b/drivers/net/tun.c > > index af372d0..eb68937 100644 > > --- a/drivers/net/tun.c > > +++ b/drivers/net/tun.c > > @@ -307,7 +307,7 @@ static void tun_flow_update(struct tun_struct *tun, > > u32 rxhash,> > > rcu_read_lock(); > > > > - if (tun->numqueues == 1) > > + if (tun->numqueues == 1 || queue_index >= tun->numqueues) > > > > goto unlock; > > > > e = tun_flow_find(head, rxhash); > > Hmm I don't understand - does something ensure that queue_index is > > numqueues if the queue is disabled? I miss this, something is needed. > Can we check tun->disabled and skip tun_flow_update completely? > We might need to switch to rcu_assign for tun->disabled for this > but otherwise it looks easy. Correct, will post another version, thanks. > > > @@ -406,21 +406,21 @@ static void __tun_detach(struct tun_file *tfile, > > bool clean)> > > tun = rtnl_dereference(tfile->tun); > > > > - if (tun) { > > + if (tun && !tfile->detached) { > > > > u16 index = tfile->queue_index; > > BUG_ON(index >= tun->numqueues); > > dev = tun->dev; > > > > rcu_assign_pointer(tun->tfiles[index], > > > > tun->tfiles[tun->numqueues - 1]); > > > > - rcu_assign_pointer(tfile->tun, NULL); > > > > ntfile = rtnl_dereference(tun->tfiles[index]); > > ntfile->queue_index = index; > > > > --tun->numqueues; > > > > - if (clean) > > + if (clean) { > > + rcu_assign_pointer(tfile->tun, NULL); > > > > sock_put(&tfile->sk); > > > > - else > > + } else > > > > tun_disable_queue(tun, tfile); > > > > synchronize_net(); > > > > @@ -465,6 +465,10 @@ static void tun_detach_all(struct net_device *dev) > > > > rcu_assign_pointer(tfile->tun, NULL); > > --tun->numqueues; > > > > } > > > > + list_for_each_entry(tfile, &tun->disabled, next) { > > + wake_up_all(&tfile->wq.wait); > > + rcu_assign_pointer(tfile->tun, NULL); > > + } > > > > BUG_ON(tun->numqueues != 0); > > > > synchronize_net(); > > > > @@ -491,7 +495,7 @@ static int tun_attach(struct tun_struct *tun, struct > > file *file)> > > int err; > > > > err = -EINVAL; > > > > - if (rtnl_dereference(tfile->tun)) > > + if (rtnl_dereference(tfile->tun) && !tfile->detached) > > > > goto out; > > > > err = -EBUSY; > > > > @@ -1795,7 +1799,7 @@ static int tun_set_queue(struct file *file, struct > > ifreq *ifr)> > > ret = tun_attach(tun, file); > > > > } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) { > > > > tun = rtnl_dereference(tfile->tun); > > > > - if (!tun || !(tun->flags & TUN_TAP_MQ)) > > + if (!tun || !(tun->flags & TUN_TAP_MQ) || tfile->detached) > > > > ret = -EINVAL; > > > > else > > > > __tun_detach(tfile, false); > > -- > To unsubscribe from this list: send the line "unsubscribe netdev" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Patch
diff --git a/drivers/net/tun.c b/drivers/net/tun.c index af372d0..eb68937 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -307,7 +307,7 @@ static void tun_flow_update(struct tun_struct *tun, u32 rxhash, rcu_read_lock(); - if (tun->numqueues == 1) + if (tun->numqueues == 1 || queue_index >= tun->numqueues) goto unlock; e = tun_flow_find(head, rxhash); @@ -406,21 +406,21 @@ static void __tun_detach(struct tun_file *tfile, bool clean) tun = rtnl_dereference(tfile->tun); - if (tun) { + if (tun && !tfile->detached) { u16 index = tfile->queue_index; BUG_ON(index >= tun->numqueues); dev = tun->dev; rcu_assign_pointer(tun->tfiles[index], tun->tfiles[tun->numqueues - 1]); - rcu_assign_pointer(tfile->tun, NULL); ntfile = rtnl_dereference(tun->tfiles[index]); ntfile->queue_index = index; --tun->numqueues; - if (clean) + if (clean) { + rcu_assign_pointer(tfile->tun, NULL); sock_put(&tfile->sk); - else + } else tun_disable_queue(tun, tfile); synchronize_net(); @@ -465,6 +465,10 @@ static void tun_detach_all(struct net_device *dev) rcu_assign_pointer(tfile->tun, NULL); --tun->numqueues; } + list_for_each_entry(tfile, &tun->disabled, next) { + wake_up_all(&tfile->wq.wait); + rcu_assign_pointer(tfile->tun, NULL); + } BUG_ON(tun->numqueues != 0); synchronize_net(); @@ -491,7 +495,7 @@ static int tun_attach(struct tun_struct *tun, struct file *file) int err; err = -EINVAL; - if (rtnl_dereference(tfile->tun)) + if (rtnl_dereference(tfile->tun) && !tfile->detached) goto out; err = -EBUSY; @@ -1795,7 +1799,7 @@ static int tun_set_queue(struct file *file, struct ifreq *ifr) ret = tun_attach(tun, file); } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) { tun = rtnl_dereference(tfile->tun); - if (!tun || !(tun->flags & TUN_TAP_MQ)) + if (!tun || !(tun->flags & TUN_TAP_MQ) || tfile->detached) ret = -EINVAL; else __tun_detach(tfile, false);
We forbid polling, writing and reading when the file were detached, this may complex the user in several cases: - when guest pass some buffers to vhost/qemu and then disable some queues, vhost/qemu needs to to its own cleanup which is complex. We can do this simply by allowing a user can still write to an disabled queue to handle this. And user can still do read but just nothing returned. - align the polling behavior with macvtap which never fails when the queue is created. this can simplify the polling errors handling of its user (e.g vhost) Signed-off-by: Jason Wang <jasowang@redhat.com> --- drivers/net/tun.c | 18 +++++++++++------- 1 files changed, 11 insertions(+), 7 deletions(-)