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Message-ID: <20120626115420.GD13108@redhat.com>
Date: Tue, 26 Jun 2012 14:54:20 +0300
From: "Michael S. Tsirkin" <mst@...hat.com>
To: Jason Wang <jasowang@...hat.com>
Cc: habanero@...ux.vnet.ibm.com, netdev@...r.kernel.org,
linux-kernel@...r.kernel.org, krkumar2@...ibm.com,
tahm@...ux.vnet.ibm.com, akong@...hat.com, davem@...emloft.net,
shemminger@...tta.com, mashirle@...ibm.com,
Eric Dumazet <eric.dumazet@...il.com>
Subject: Re: [net-next RFC V3 PATCH 4/6] tuntap: multiqueue support
On Tue, Jun 26, 2012 at 01:52:57PM +0800, Jason Wang wrote:
> On 06/25/2012 04:25 PM, Michael S. Tsirkin wrote:
> >On Mon, Jun 25, 2012 at 02:10:18PM +0800, Jason Wang wrote:
> >>This patch adds multiqueue support for tap device. This is done by abstracting
> >>each queue as a file/socket and allowing multiple sockets to be attached to the
> >>tuntap device (an array of tun_file were stored in the tun_struct). Userspace
> >>could write and read from those files to do the parallel packet
> >>sending/receiving.
> >>
> >>Unlike the previous single queue implementation, the socket and device were
> >>loosely coupled, each of them were allowed to go away first. In order to let the
> >>tx path lockless, netif_tx_loch_bh() is replaced by RCU/NETIF_F_LLTX to
> >>synchronize between data path and system call.
> >Don't use LLTX/RCU. It's not worth it.
> >Use something like netif_set_real_num_tx_queues.
> >
>
> For LLTX, maybe it's better to convert it to alloc_netdev_mq() to
> let the kernel see all queues and make the queue stopping and
> per-queue stats eaiser.
> RCU is used to handle the attaching/detaching when tun/tap is
> sending and receiving packets which looks reasonalbe for me.
Yes but do we have to allow this? How about we always ask
userspace to attach to all active queues?
> Not
> sure netif_set_real_num_tx_queues() can help in this situation.
Check it out.
> >>The tx queue selecting is first based on the recorded rxq index of an skb, it
> >>there's no such one, then choosing based on rx hashing (skb_get_rxhash()).
> >>
> >>Signed-off-by: Jason Wang<jasowang@...hat.com>
> >Interestingly macvtap switched to hashing first:
> >ef0002b577b52941fb147128f30bd1ecfdd3ff6d
> >(the commit log is corrupted but see what it
> >does in the patch).
> >Any idea why?
> >
> >>---
> >> drivers/net/tun.c | 371 +++++++++++++++++++++++++++++++++--------------------
> >> 1 files changed, 232 insertions(+), 139 deletions(-)
> >>
> >>diff --git a/drivers/net/tun.c b/drivers/net/tun.c
> >>index 8233b0a..5c26757 100644
> >>--- a/drivers/net/tun.c
> >>+++ b/drivers/net/tun.c
> >>@@ -107,6 +107,8 @@ struct tap_filter {
> >> unsigned char addr[FLT_EXACT_COUNT][ETH_ALEN];
> >> };
> >>
> >>+#define MAX_TAP_QUEUES (NR_CPUS< 16 ? NR_CPUS : 16)
> >Why the limit? I am guessing you copied this from macvtap?
> >This is problematic for a number of reasons:
> > - will not play well with migration
> > - will not work well for a large guest
> >
> >Yes, macvtap needs to be fixed too.
> >
> >I am guessing what it is trying to prevent is queueing
> >up a huge number of packets?
> >So just divide the default tx queue limit by the # of queues.
>
> Not sure,
> another reasons I can guess:
> - to prevent storing a large array of pointers in tun_struct or macvlan_dev.
OK so with the limit of e.g. 1024 we'd allocate at most
2 pages of memory. This doesn't look too bad. 1024 is probably a
high enough limit: modern hypervisors seem to support on the order
of 100-200 CPUs so this leaves us some breathing space
if we want to match a queue per guest CPU.
Of course we need to limit the packets per queue
in such a setup more aggressively. 1000 packets * 1000 queues
* 64K per packet is too much.
> - it may not be suitable to allow the number of virtqueues greater
> than the number of physical queues in the card
Maybe for macvtap, here we have no idea which card we
are working with and how many queues it has.
> >
> >And by the way, for MQ applications maybe we can finally
> >ignore tx queue altogether and limit the total number
> >of bytes queued?
> >To avoid regressions we can make it large like 64M/# queues.
> >Could be a separate patch I think, and for a single queue
> >might need a compatible mode though I am not sure.
>
> Could you explain more about this?
> Did you mean to have a total
> sndbuf for all sockets that attached to tun/tap?
Consider that we currently limit the # of
packets queued at tun for xmit to userspace.
Some limit is needed but # of packets sounds
very silly - limiting the total memory
might be more reasonable.
In case of multiqueue, we really care about
total # of packets or total memory, but a simple
approximation could be to divide the allocation
between active queues equally.
qdisc also queues some packets, that logic is
using # of packets anyway. So either make that
1000/# queues, or even set to 0 as Eric once
suggested.
> >>+
> >> struct tun_file {
> >> struct sock sk;
> >> struct socket socket;
> >>@@ -114,16 +116,18 @@ struct tun_file {
> >> int vnet_hdr_sz;
> >> struct tap_filter txflt;
> >> atomic_t count;
> >>- struct tun_struct *tun;
> >>+ struct tun_struct __rcu *tun;
> >> struct net *net;
> >> struct fasync_struct *fasync;
> >> unsigned int flags;
> >>+ u16 queue_index;
> >> };
> >>
> >> struct tun_sock;
> >>
> >> struct tun_struct {
> >>- struct tun_file *tfile;
> >>+ struct tun_file *tfiles[MAX_TAP_QUEUES];
> >>+ unsigned int numqueues;
> >> unsigned int flags;
> >> uid_t owner;
> >> gid_t group;
> >>@@ -138,80 +142,159 @@ struct tun_struct {
> >> #endif
> >> };
> >>
> >>-static int tun_attach(struct tun_struct *tun, struct file *file)
> >>+static DEFINE_SPINLOCK(tun_lock);
> >>+
> >>+/*
> >>+ * tun_get_queue(): calculate the queue index
> >>+ * - if skbs comes from mq nics, we can just borrow
> >>+ * - if not, calculate from the hash
> >>+ */
> >>+static struct tun_file *tun_get_queue(struct net_device *dev,
> >>+ struct sk_buff *skb)
> >> {
> >>- struct tun_file *tfile = file->private_data;
> >>- int err;
> >>+ struct tun_struct *tun = netdev_priv(dev);
> >>+ struct tun_file *tfile = NULL;
> >>+ int numqueues = tun->numqueues;
> >>+ __u32 rxq;
> >>
> >>- ASSERT_RTNL();
> >>+ BUG_ON(!rcu_read_lock_held());
> >>
> >>- netif_tx_lock_bh(tun->dev);
> >>+ if (!numqueues)
> >>+ goto out;
> >>
> >>- err = -EINVAL;
> >>- if (tfile->tun)
> >>+ if (numqueues == 1) {
> >>+ tfile = rcu_dereference(tun->tfiles[0]);
> >Instead of hacks like this, you can ask for an MQ
> >flag to be set in SETIFF. Then you won't need to
> >handle attach/detach at random times.
>
> Consier user switch between a sq guest to mq guest, qemu would
> attach or detach the fd which could not be expceted in kernel.
Can't userspace keep it attached always, just deactivate MQ?
> >And most of the scary num_queues checks can go away.
>
> Even we has a MQ flag, userspace could still just attach one queue
> to the device.
I think we allow too much flexibility if we let
userspace detach a random queue.
Maybe only allow attaching/detaching with MQ off?
If userspace wants to attach/detach, clear MQ first?
Alternatively, attach/detach all queues in one ioctl?
> >You can then also ask userspace about the max # of queues
> >to expect if you want to save some memory.
> >
>
> Yes, good suggestion.
> >> goto out;
> >>+ }
> >>
> >>- err = -EBUSY;
> >>- if (tun->tfile)
> >>+ if (likely(skb_rx_queue_recorded(skb))) {
> >>+ rxq = skb_get_rx_queue(skb);
> >>+
> >>+ while (unlikely(rxq>= numqueues))
> >>+ rxq -= numqueues;
> >>+
> >>+ tfile = rcu_dereference(tun->tfiles[rxq]);
> >> goto out;
> >>+ }
> >>
> >>- err = 0;
> >>- tfile->tun = tun;
> >>- tun->tfile = tfile;
> >>- netif_carrier_on(tun->dev);
> >>- dev_hold(tun->dev);
> >>- sock_hold(&tfile->sk);
> >>- atomic_inc(&tfile->count);
> >>+ /* Check if we can use flow to select a queue */
> >>+ rxq = skb_get_rxhash(skb);
> >>+ if (rxq) {
> >>+ u32 idx = ((u64)rxq * numqueues)>> 32;
> >This completely confuses me. What's the logic here?
> >How do we even know it's in range?
> >
>
> rxq is a u32, so the result should be less than numqueues.
Aha. So the point is to use multiply+shift instead of %?
Please add a comment.
> >>+ tfile = rcu_dereference(tun->tfiles[idx]);
> >>+ goto out;
> >>+ }
> >>
> >>+ tfile = rcu_dereference(tun->tfiles[0]);
> >> out:
> >>- netif_tx_unlock_bh(tun->dev);
> >>- return err;
> >>+ return tfile;
> >> }
> >>
> >>-static void __tun_detach(struct tun_struct *tun)
> >>+static int tun_detach(struct tun_file *tfile, bool clean)
> >> {
> >>- struct tun_file *tfile = tun->tfile;
> >>- /* Detach from net device */
> >>- netif_tx_lock_bh(tun->dev);
> >>- netif_carrier_off(tun->dev);
> >>- tun->tfile = NULL;
> >>- netif_tx_unlock_bh(tun->dev);
> >>-
> >>- /* Drop read queue */
> >>- skb_queue_purge(&tfile->socket.sk->sk_receive_queue);
> >>-
> >>- /* Drop the extra count on the net device */
> >>- dev_put(tun->dev);
> >>-}
> >>+ struct tun_struct *tun;
> >>+ struct net_device *dev = NULL;
> >>+ bool destroy = false;
> >>
> >>-static void tun_detach(struct tun_struct *tun)
> >>-{
> >>- rtnl_lock();
> >>- __tun_detach(tun);
> >>- rtnl_unlock();
> >>-}
> >>+ spin_lock(&tun_lock);
> >>
> >>-static struct tun_struct *__tun_get(struct tun_file *tfile)
> >>-{
> >>- struct tun_struct *tun = NULL;
> >>+ tun = rcu_dereference_protected(tfile->tun,
> >>+ lockdep_is_held(&tun_lock));
> >>+ if (tun) {
> >>+ u16 index = tfile->queue_index;
> >>+ BUG_ON(index>= tun->numqueues);
> >>+ dev = tun->dev;
> >>+
> >>+ rcu_assign_pointer(tun->tfiles[index],
> >>+ tun->tfiles[tun->numqueues - 1]);
> >>+ tun->tfiles[index]->queue_index = index;
> >>+ rcu_assign_pointer(tfile->tun, NULL);
> >>+ --tun->numqueues;
> >>+ sock_put(&tfile->sk);
> >>
> >>- if (atomic_inc_not_zero(&tfile->count))
> >>- tun = tfile->tun;
> >>+ if (tun->numqueues == 0&& !(tun->flags& TUN_PERSIST))
> >>+ destroy = true;
> >Please don't use flags like that. Use dedicated labels and goto there on error.
>
> ok.
> >
> >>+ }
> >>
> >>- return tun;
> >>+ spin_unlock(&tun_lock);
> >>+
> >>+ synchronize_rcu();
> >>+ if (clean)
> >>+ sock_put(&tfile->sk);
> >>+
> >>+ if (destroy) {
> >>+ rtnl_lock();
> >>+ if (dev->reg_state == NETREG_REGISTERED)
> >>+ unregister_netdevice(dev);
> >>+ rtnl_unlock();
> >>+ }
> >>+
> >>+ return 0;
> >> }
> >>
> >>-static struct tun_struct *tun_get(struct file *file)
> >>+static void tun_detach_all(struct net_device *dev)
> >> {
> >>- return __tun_get(file->private_data);
> >>+ struct tun_struct *tun = netdev_priv(dev);
> >>+ struct tun_file *tfile, *tfile_list[MAX_TAP_QUEUES];
> >>+ int i, j = 0;
> >>+
> >>+ spin_lock(&tun_lock);
> >>+
> >>+ for (i = 0; i< MAX_TAP_QUEUES&& tun->numqueues; i++) {
> >>+ tfile = rcu_dereference_protected(tun->tfiles[i],
> >>+ lockdep_is_held(&tun_lock));
> >>+ BUG_ON(!tfile);
> >>+ wake_up_all(&tfile->wq.wait);
> >>+ tfile_list[j++] = tfile;
> >>+ rcu_assign_pointer(tfile->tun, NULL);
> >>+ --tun->numqueues;
> >>+ }
> >>+ BUG_ON(tun->numqueues != 0);
> >>+ /* guarantee that any future tun_attach will fail */
> >>+ tun->numqueues = MAX_TAP_QUEUES;
> >>+ spin_unlock(&tun_lock);
> >>+
> >>+ synchronize_rcu();
> >>+ for (--j; j>= 0; j--)
> >>+ sock_put(&tfile_list[j]->sk);
> >> }
> >>
> >>-static void tun_put(struct tun_struct *tun)
> >>+static int tun_attach(struct tun_struct *tun, struct file *file)
> >> {
> >>- struct tun_file *tfile = tun->tfile;
> >>+ struct tun_file *tfile = file->private_data;
> >>+ int err;
> >>+
> >>+ ASSERT_RTNL();
> >>+
> >>+ spin_lock(&tun_lock);
> >>
> >>- if (atomic_dec_and_test(&tfile->count))
> >>- tun_detach(tfile->tun);
> >>+ err = -EINVAL;
> >>+ if (rcu_dereference_protected(tfile->tun, lockdep_is_held(&tun_lock)))
> >>+ goto out;
> >>+
> >>+ err = -EBUSY;
> >>+ if (!(tun->flags& TUN_TAP_MQ)&& tun->numqueues == 1)
> >>+ goto out;
> >>+
> >>+ if (tun->numqueues == MAX_TAP_QUEUES)
> >>+ goto out;
> >>+
> >>+ err = 0;
> >>+ tfile->queue_index = tun->numqueues;
> >>+ rcu_assign_pointer(tfile->tun, tun);
> >>+ rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile);
> >>+ sock_hold(&tfile->sk);
> >>+ tun->numqueues++;
> >>+
> >>+ if (tun->numqueues == 1)
> >>+ netif_carrier_on(tun->dev);
> >>+
> >>+ /* device is allowed to go away first, so no need to hold extra
> >>+ * refcnt. */
> >>+
> >>+out:
> >>+ spin_unlock(&tun_lock);
> >>+ return err;
> >> }
> >>
> >> /* TAP filtering */
> >>@@ -331,16 +414,7 @@ static const struct ethtool_ops tun_ethtool_ops;
> >> /* Net device detach from fd. */
> >> static void tun_net_uninit(struct net_device *dev)
> >> {
> >>- struct tun_struct *tun = netdev_priv(dev);
> >>- struct tun_file *tfile = tun->tfile;
> >>-
> >>- /* Inform the methods they need to stop using the dev.
> >>- */
> >>- if (tfile) {
> >>- wake_up_all(&tfile->wq.wait);
> >>- if (atomic_dec_and_test(&tfile->count))
> >>- __tun_detach(tun);
> >>- }
> >>+ tun_detach_all(dev);
> >> }
> >>
> >> /* Net device open. */
> >>@@ -360,10 +434,10 @@ static int tun_net_close(struct net_device *dev)
> >> /* Net device start xmit */
> >> static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
> >> {
> >>- struct tun_struct *tun = netdev_priv(dev);
> >>- struct tun_file *tfile = tun->tfile;
> >>+ struct tun_file *tfile = NULL;
> >>
> >>- tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
> >>+ rcu_read_lock();
> >>+ tfile = tun_get_queue(dev, skb);
> >>
> >> /* Drop packet if interface is not attached */
> >> if (!tfile)
> >>@@ -381,7 +455,8 @@ static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
> >>
> >> if (skb_queue_len(&tfile->socket.sk->sk_receive_queue)
> >> >= dev->tx_queue_len) {
> >>- if (!(tun->flags& TUN_ONE_QUEUE)) {
> >>+ if (!(tfile->flags& TUN_ONE_QUEUE)&&
> >Which patch moved flags from tun to tfile?
>
> Patch 1 cache the tun->flags in tfile, but it seems this may let the
> flags out of sync. So we'd better to use the one in tun_struct.
> >
> >>+ !(tfile->flags& TUN_TAP_MQ)) {
> >> /* Normal queueing mode. */
> >> /* Packet scheduler handles dropping of further packets. */
> >> netif_stop_queue(dev);
> >>@@ -390,7 +465,7 @@ static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
> >> * error is more appropriate. */
> >> dev->stats.tx_fifo_errors++;
> >> } else {
> >>- /* Single queue mode.
> >>+ /* Single queue mode or multi queue mode.
> >> * Driver handles dropping of all packets itself. */
> >Please don't do this. Stop the queue on overrun as appropriate.
> >ONE_QUEUE is a legacy hack.
> >
> >BTW we really should stop queue before we start dropping packets,
> >but that can be a separate patch.
>
> The problem here is the using of NETIF_F_LLTX. Kernel could only see
> one queue even for a multiqueue tun/tap. If we use
> netif_stop_queue(), all other queues would be stopped also.
Another reason not to use LLTX?
> >> goto drop;
> >> }
> >>@@ -408,9 +483,11 @@ static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
> >> kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
> >> wake_up_interruptible_poll(&tfile->wq.wait, POLLIN |
> >> POLLRDNORM | POLLRDBAND);
> >>+ rcu_read_unlock();
> >> return NETDEV_TX_OK;
> >>
> >> drop:
> >>+ rcu_read_unlock();
> >> dev->stats.tx_dropped++;
> >> kfree_skb(skb);
> >> return NETDEV_TX_OK;
> >>@@ -527,16 +604,22 @@ static void tun_net_init(struct net_device *dev)
> >> static unsigned int tun_chr_poll(struct file *file, poll_table * wait)
> >> {
> >> struct tun_file *tfile = file->private_data;
> >>- struct tun_struct *tun = __tun_get(tfile);
> >>+ struct tun_struct *tun = NULL;
> >> struct sock *sk;
> >> unsigned int mask = 0;
> >>
> >>- if (!tun)
> >>+ if (!tfile)
> >> return POLLERR;
> >>
> >>- sk = tfile->socket.sk;
> >>+ rcu_read_lock();
> >>+ tun = rcu_dereference(tfile->tun);
> >>+ if (!tun) {
> >>+ rcu_read_unlock();
> >>+ return POLLERR;
> >>+ }
> >>+ rcu_read_unlock();
> >>
> >>- tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
> >>+ sk =&tfile->sk;
> >>
> >> poll_wait(file,&tfile->wq.wait, wait);
> >>
> >>@@ -548,10 +631,12 @@ static unsigned int tun_chr_poll(struct file *file, poll_table * wait)
> >> sock_writeable(sk)))
> >> mask |= POLLOUT | POLLWRNORM;
> >>
> >>- if (tun->dev->reg_state != NETREG_REGISTERED)
> >>+ rcu_read_lock();
> >>+ tun = rcu_dereference(tfile->tun);
> >>+ if (!tun || tun->dev->reg_state != NETREG_REGISTERED)
> >> mask = POLLERR;
> >>+ rcu_read_unlock();
> >>
> >>- tun_put(tun);
> >> return mask;
> >> }
> >>
> >>@@ -708,9 +793,12 @@ static ssize_t tun_get_user(struct tun_file *tfile,
> >> skb_shinfo(skb)->gso_segs = 0;
> >> }
> >>
> >>- tun = __tun_get(tfile);
> >>- if (!tun)
> >>+ rcu_read_lock();
> >>+ tun = rcu_dereference(tfile->tun);
> >>+ if (!tun) {
> >>+ rcu_read_unlock();
> >> return -EBADFD;
> >>+ }
> >>
> >> switch (tfile->flags& TUN_TYPE_MASK) {
> >> case TUN_TUN_DEV:
> >>@@ -720,26 +808,30 @@ static ssize_t tun_get_user(struct tun_file *tfile,
> >> skb->protocol = eth_type_trans(skb, tun->dev);
> >> break;
> >> }
> >>-
> >>- netif_rx_ni(skb);
> >> tun->dev->stats.rx_packets++;
> >> tun->dev->stats.rx_bytes += len;
> >>- tun_put(tun);
> >>+ rcu_read_unlock();
> >>+
> >>+ netif_rx_ni(skb);
> >>+
> >> return count;
> >>
> >> err_free:
> >> count = -EINVAL;
> >> kfree_skb(skb);
> >> err:
> >>- tun = __tun_get(tfile);
> >>- if (!tun)
> >>+ rcu_read_lock();
> >>+ tun = rcu_dereference(tfile->tun);
> >>+ if (!tun) {
> >>+ rcu_read_unlock();
> >> return -EBADFD;
> >>+ }
> >>
> >> if (drop)
> >> tun->dev->stats.rx_dropped++;
> >> if (error)
> >> tun->dev->stats.rx_frame_errors++;
> >>- tun_put(tun);
> >>+ rcu_read_unlock();
> >> return count;
> >> }
> >>
> >>@@ -833,12 +925,13 @@ static ssize_t tun_put_user(struct tun_file *tfile,
> >> skb_copy_datagram_const_iovec(skb, 0, iv, total, len);
> >> total += skb->len;
> >>
> >>- tun = __tun_get(tfile);
> >>+ rcu_read_lock();
> >>+ tun = rcu_dereference(tfile->tun);
> >> if (tun) {
> >> tun->dev->stats.tx_packets++;
> >> tun->dev->stats.tx_bytes += len;
> >>- tun_put(tun);
> >> }
> >>+ rcu_read_unlock();
> >>
> >> return total;
> >> }
> >>@@ -869,28 +962,31 @@ static ssize_t tun_do_read(struct tun_file *tfile,
> >> break;
> >> }
> >>
> >>- tun = __tun_get(tfile);
> >>+ rcu_read_lock();
> >>+ tun = rcu_dereference(tfile->tun);
> >> if (!tun) {
> >>- ret = -EIO;
> >>+ ret = -EBADFD;
> >BADFD is for when you get passed something like -1 fd.
> >Here fd is OK, it's just in a bad state so you can not do IO.
> >
>
> Sure.
> >>+ rcu_read_unlock();
> >> break;
> >> }
> >> if (tun->dev->reg_state != NETREG_REGISTERED) {
> >> ret = -EIO;
> >>- tun_put(tun);
> >>+ rcu_read_unlock();
> >> break;
> >> }
> >>- tun_put(tun);
> >>+ rcu_read_unlock();
> >>
> >> /* Nothing to read, let's sleep */
> >> schedule();
> >> continue;
> >> }
> >>
> >>- tun = __tun_get(tfile);
> >>+ rcu_read_lock();
> >>+ tun = rcu_dereference(tfile->tun);
> >> if (tun) {
> >> netif_wake_queue(tun->dev);
> >>- tun_put(tun);
> >> }
> >>+ rcu_read_unlock();
> >>
> >> ret = tun_put_user(tfile, skb, iv, len);
> >> kfree_skb(skb);
> >>@@ -1038,6 +1134,9 @@ static int tun_flags(struct tun_struct *tun)
> >> if (tun->flags& TUN_VNET_HDR)
> >> flags |= IFF_VNET_HDR;
> >>
> >>+ if (tun->flags& TUN_TAP_MQ)
> >>+ flags |= IFF_MULTI_QUEUE;
> >>+
> >> return flags;
> >> }
> >>
> >>@@ -1097,8 +1196,7 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
> >> err = tun_attach(tun, file);
> >> if (err< 0)
> >> return err;
> >>- }
> >>- else {
> >>+ } else {
> >> char *name;
> >> unsigned long flags = 0;
> >>
> >>@@ -1142,6 +1240,8 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
> >> dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
> >> TUN_USER_FEATURES;
> >> dev->features = dev->hw_features;
> >>+ if (ifr->ifr_flags& IFF_MULTI_QUEUE)
> >>+ dev->features |= NETIF_F_LLTX;
> >>
> >> err = register_netdevice(tun->dev);
> >> if (err< 0)
> >>@@ -1154,7 +1254,7 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
> >>
> >> err = tun_attach(tun, file);
> >> if (err< 0)
> >>- goto failed;
> >>+ goto err_free_dev;
> >> }
> >>
> >> tun_debug(KERN_INFO, tun, "tun_set_iff\n");
> >>@@ -1174,6 +1274,11 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
> >> else
> >> tun->flags&= ~TUN_VNET_HDR;
> >>
> >>+ if (ifr->ifr_flags& IFF_MULTI_QUEUE)
> >>+ tun->flags |= TUN_TAP_MQ;
> >>+ else
> >>+ tun->flags&= ~TUN_TAP_MQ;
> >>+
> >> /* Cache flags from tun device */
> >> tfile->flags = tun->flags;
> >> /* Make sure persistent devices do not get stuck in
> >>@@ -1187,7 +1292,6 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
> >>
> >> err_free_dev:
> >> free_netdev(dev);
> >>-failed:
> >> return err;
> >> }
> >>
> >>@@ -1264,38 +1368,40 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
> >> (unsigned int __user*)argp);
> >> }
> >>
> >>- rtnl_lock();
> >>-
> >>- tun = __tun_get(tfile);
> >>- if (cmd == TUNSETIFF&& !tun) {
> >>+ ret = 0;
> >>+ if (cmd == TUNSETIFF) {
> >>+ rtnl_lock();
> >> ifr.ifr_name[IFNAMSIZ-1] = '\0';
> >>-
> >> ret = tun_set_iff(tfile->net, file,&ifr);
> >>-
> >>+ rtnl_unlock();
> >> if (ret)
> >>- goto unlock;
> >>-
> >>+ return ret;
> >> if (copy_to_user(argp,&ifr, ifreq_len))
> >>- ret = -EFAULT;
> >>- goto unlock;
> >>+ return -EFAULT;
> >>+ return ret;
> >> }
> >>
> >>+ rtnl_lock();
> >>+
> >>+ rcu_read_lock();
> >>+
> >> ret = -EBADFD;
> >>+ tun = rcu_dereference(tfile->tun);
> >> if (!tun)
> >> goto unlock;
> >>+ else
> >>+ ret = 0;
> >>
> >>- tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %d\n", cmd);
> >>-
> >>- ret = 0;
> >> switch (cmd) {
> >> case TUNGETIFF:
> >> ret = tun_get_iff(current->nsproxy->net_ns, tun,&ifr);
> >>+ rcu_read_unlock();
> >> if (ret)
> >>- break;
> >>+ goto out;
> >>
> >> if (copy_to_user(argp,&ifr, ifreq_len))
> >> ret = -EFAULT;
> >>- break;
> >>+ goto out;
> >>
> >> case TUNSETNOCSUM:
> >> /* Disable/Enable checksum */
> >>@@ -1357,9 +1463,10 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
> >> /* Get hw address */
> >> memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
> >> ifr.ifr_hwaddr.sa_family = tun->dev->type;
> >>+ rcu_read_unlock();
> >> if (copy_to_user(argp,&ifr, ifreq_len))
> >> ret = -EFAULT;
> >>- break;
> >>+ goto out;
> >>
> >> case SIOCSIFHWADDR:
> >> /* Set hw address */
> >>@@ -1375,9 +1482,9 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
> >> }
> >>
> >> unlock:
> >>+ rcu_read_unlock();
> >>+out:
> >> rtnl_unlock();
> >>- if (tun)
> >>- tun_put(tun);
> >> return ret;
> >> }
> >>
> >>@@ -1517,6 +1624,11 @@ out:
> >> return ret;
> >> }
> >>
> >>+static void tun_sock_destruct(struct sock *sk)
> >>+{
> >>+ skb_queue_purge(&sk->sk_receive_queue);
> >>+}
> >>+
> >> static int tun_chr_open(struct inode *inode, struct file * file)
> >> {
> >> struct net *net = current->nsproxy->net_ns;
> >>@@ -1540,6 +1652,7 @@ static int tun_chr_open(struct inode *inode, struct file * file)
> >> sock_init_data(&tfile->socket,&tfile->sk);
> >>
> >> tfile->sk.sk_write_space = tun_sock_write_space;
> >>+ tfile->sk.sk_destruct = tun_sock_destruct;
> >> tfile->sk.sk_sndbuf = INT_MAX;
> >> file->private_data = tfile;
> >>
> >>@@ -1549,31 +1662,8 @@ static int tun_chr_open(struct inode *inode, struct file * file)
> >> static int tun_chr_close(struct inode *inode, struct file *file)
> >> {
> >> struct tun_file *tfile = file->private_data;
> >>- struct tun_struct *tun;
> >>-
> >>- tun = __tun_get(tfile);
> >>- if (tun) {
> >>- struct net_device *dev = tun->dev;
> >>-
> >>- tun_debug(KERN_INFO, tun, "tun_chr_close\n");
> >>-
> >>- __tun_detach(tun);
> >>-
> >>- /* If desirable, unregister the netdevice. */
> >>- if (!(tun->flags& TUN_PERSIST)) {
> >>- rtnl_lock();
> >>- if (dev->reg_state == NETREG_REGISTERED)
> >>- unregister_netdevice(dev);
> >>- rtnl_unlock();
> >>- }
> >>
> >>- /* drop the reference that netdevice holds */
> >>- sock_put(&tfile->sk);
> >>-
> >>- }
> >>-
> >>- /* drop the reference that file holds */
> >>- sock_put(&tfile->sk);
> >>+ tun_detach(tfile, true);
> >>
> >> return 0;
> >> }
> >>@@ -1700,14 +1790,17 @@ static void tun_cleanup(void)
> >> * holding a reference to the file for as long as the socket is in use. */
> >> struct socket *tun_get_socket(struct file *file)
> >> {
> >>- struct tun_struct *tun;
> >>+ struct tun_struct *tun = NULL;
> >> struct tun_file *tfile = file->private_data;
> >> if (file->f_op !=&tun_fops)
> >> return ERR_PTR(-EINVAL);
> >>- tun = tun_get(file);
> >>- if (!tun)
> >>+ rcu_read_lock();
> >>+ tun = rcu_dereference(tfile->tun);
> >>+ if (!tun) {
> >>+ rcu_read_unlock();
> >> return ERR_PTR(-EBADFD);
> >>- tun_put(tun);
> >>+ }
> >>+ rcu_read_unlock();
> >> return&tfile->socket;
> >> }
> >> EXPORT_SYMBOL_GPL(tun_get_socket);
--
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