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path: root/drivers/net/ifb.c
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2011-11-17net: remove NETIF_F_NO_CSUM feature bitMichał Mirosław1-1/+1
Only distinct use is checking if NETIF_F_NOCACHE_COPY should be enabled by default. The check heuristics is altered a bit here, so it hits other people than before. The default shouldn't be trusted for performance-critical cases anyway. For all other uses NETIF_F_NO_CSUM is equivalent to NETIF_F_HW_CSUM. Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-07-28net: Audit drivers to identify those needing IFF_TX_SKB_SHARING clearedNeil Horman1-1/+1
After the last patch, We are left in a state in which only drivers calling ether_setup have IFF_TX_SKB_SHARING set (we assume that drivers touching real hardware call ether_setup for their net_devices and don't hold any state in their skbs. There are a handful of drivers that violate this assumption of course, and need to be fixed up. This patch identifies those drivers, and marks them as not being able to support the safe transmission of skbs by clearning the IFF_TX_SKB_SHARING flag in priv_flags Signed-off-by: Neil Horman <nhorman@tuxdriver.com> CC: Karsten Keil <isdn@linux-pingi.de> CC: "David S. Miller" <davem@davemloft.net> CC: Jay Vosburgh <fubar@us.ibm.com> CC: Andy Gospodarek <andy@greyhouse.net> CC: Patrick McHardy <kaber@trash.net> CC: Krzysztof Halasa <khc@pm.waw.pl> CC: "John W. Linville" <linville@tuxdriver.com> CC: Greg Kroah-Hartman <gregkh@suse.de> CC: Marcel Holtmann <marcel@holtmann.org> CC: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-06-22ifb: convert to 64 bit statsstephen hemminger1-9/+47
Convert input functional block device to use 64 bit stats. Signed-off-by: Stephen Hemminger <shemminger@vyatta.com> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Acked-by: Jamal Hadi Salim <hadi@cyberus.ca> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-06-07net: remove interrupt.h inclusion from netdevice.hAlexey Dobriyan1-0/+1
* remove interrupt.g inclusion from netdevice.h -- not needed * fixup fallout, add interrupt.h and hardirq.h back where needed. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-05-05net: call dev_alloc_name from register_netdeviceJiri Pirko1-4/+0
Force dev_alloc_name() to be called from register_netdevice() by dev_get_valid_name(). That allows to remove multiple explicit dev_alloc_name() calls. The possibility to call dev_alloc_name in advance remains. This also fixes veth creation regresion caused by 84c49d8c3e4abefb0a41a77b25aa37ebe8d6b743 Signed-off-by: Jiri Pirko <jpirko@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-01-03ifb: add performance flagsEric Dumazet1-0/+7
Le lundi 03 janvier 2011 à 11:40 -0800, David Miller a écrit : > From: Jarek Poplawski <jarkao2@gmail.com> > Date: Mon, 3 Jan 2011 20:37:03 +0100 > > > On Sun, Jan 02, 2011 at 09:24:36PM +0100, Eric Dumazet wrote: > >> Le mercredi 29 décembre 2010 ?? 00:07 +0100, Jarek Poplawski a écrit : > >> > >> > Ingress is before vlans handler so these features and the > >> > NETIF_F_HW_VLAN_TX flag seem useful for ifb considering > >> > dev_hard_start_xmit() checks. > >> > >> OK, here is v2 of the patch then, thanks everybody. > >> > >> > >> [PATCH v2 net-next-2.6] ifb: add performance flags > >> > >> IFB can use the full set of features flags (NETIF_F_SG | > >> NETIF_F_FRAGLIST | NETIF_F_TSO | NETIF_F_NO_CSUM | NETIF_F_HIGHDMA) to > >> avoid unnecessary split of some packets (GRO for example) > >> > >> Changli suggested to also set vlan_features, > > > > He also suggested more GSO flags of which especially NETIF_F_TSO6 > > seems interesting (wrt GRO)? > > I think at least TSO6 would very much be appropriate here. Yes, why not, I am only wondering why loopback / dummy (and others ?) only set NETIF_F_TSO :) Since I want to play with ECN, I might also add NETIF_F_TSO_ECN ;) For other flags, I really doubt it can matter on ifb ? [PATCH v3 net-next-2.6] ifb: add performance flags IFB can use the full set of features flags (NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_TSO | NETIF_F_NO_CSUM | NETIF_F_HIGHDMA) to avoid unnecessary split of some packets (GRO for example) Changli suggested to also set vlan_features, NETIF_F_TSO6, NETIF_F_TSO_ECN. Jarek suggested to add NETIF_F_HW_VLAN_TX as well. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Cc: Changli Gao <xiaosuo@gmail.com> Cc: Jarek Poplawski <jarkao2@gmail.com> Cc: Pawel Staszewski <pstaszewski@itcare.pl> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-12-20ifb: use netif_receive_skb() instead of netif_rx()Eric Dumazet1-1/+1
In ri_tasklet(), we run from softirq, so can directly handle packet through netif_receive_skb() instead of netif_rx(). There is no risk of recursion. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Acked-by: Changli Gao <xiaosuo@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-12-17ifb: fix a lockdep splatEric Dumazet1-1/+1
After recent ifb changes, we must use lockless __skb_dequeue() since lock is not anymore initialized. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Cc: Jamal Hadi Salim <hadi@cyberus.ca> Cc: Changli Gao <xiaosuo@gmail.com> Acked-by: Changli Gao <xiaosuo@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-12-11ifb: use the lockless variants of skb_queueChangli Gao1-8/+6
rq and tq are both protected by tx queue lock, so we can simply use the lockless variants of skb_queue. skb_queue_splice_tail_init() is used instead of the open coded and slow one. Signed-off-by: Changli Gao <xiaosuo@gmail.com> Signed-off-by: Jamal Hadi Salim <hadi@cyberus.ca> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-12-11ifb: remove unused macro TX_TIMEOUTChangli Gao1-2/+0
Signed-off-by: Changli Gao <xiaosuo@gmail.com> Signed-off-by: Jamal Hadi Salim <hadi@cyberus.ca> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-12-11ifb: remove the useless debug statsChangli Gao1-19/+0
These debug stats are not exported, and become useless. Signed-off-by: Changli Gao <xiaosuo@gmail.com> Signed-off-by: Jamal Hadi Salim <hadi@cyberus.ca> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-12-08ifb: goto resched directly if error happens and dp->tq isn't emptyChangli Gao1-0/+2
If we break the loop when there are still skbs in tq and no skb in rq, the skbs will be left in txq until new skbs are enqueued into rq. In rare cases, no new skb is queued, then these skbs will stay in rq forever. After this patch, if tq isn't empty when we break the loop, we goto resched directly. Signed-off-by: Changli Gao <xiaosuo@gmail.com> Signed-off-by: Jamal Hadi Salim <hadi@cyberus.ca> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-05-10net: trans_start cleanupsEric Dumazet1-1/+0
Now that core network takes care of trans_start updates, dont do it in drivers themselves, if possible. Drivers can avoid one cache miss (on dev->trans_start) in their start_xmit() handler. Exceptions are NETIF_F_LLTX drivers Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-11-21net: rename skb->iif to skb->skb_iifEric Dumazet1-3/+3
To help grep games, rename iif to skb_iif Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-11-02ifb: RCU locking avoids touching dev refcountEric Dumazet1-2/+4
Avoids touching dev refcount in hotpath Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-10-23ifb: should not use __dev_get_by_index() without locksEric Dumazet1-1/+2
At this point (ri_tasklet()), RTNL or dev_base_lock are not held, we must use dev_get_by_index() instead of __dev_get_by_index() Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-09-01netdev: convert pseudo drivers to netdev_tx_tStephen Hemminger1-5/+4
These are all drivers that don't touch real hardware. Signed-off-by: Stephen Hemminger <shemminger@vyatta.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-07-06net: convert remaining non-symbolic return values in ndo_start_xmit() functionsPatrick McHardy1-1/+1
This patch converts the remaining occurences of raw return values to their symbolic counterparts in ndo_start_xmit() functions that were missed by the previous automatic conversion. Additionally code that assumed the symbolic value of NETDEV_TX_OK to be zero is changed to explicitly use NETDEV_TX_OK. Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-05-19net: release dst entry in dev_hard_start_xmit()Eric Dumazet1-0/+1
One point of contention in high network loads is the dst_release() performed when a transmited skb is freed. This is because NIC tx completion calls dev_kree_skb() long after original call to dev_queue_xmit(skb). CPU cache is cold and the atomic op in dst_release() stalls. On SMP, this is quite visible if one CPU is 100% handling softirqs for a network device, since dst_clone() is done by other cpus, involving cache line ping pongs. It seems right place to release dst is in dev_hard_start_xmit(), for most devices but ones that are virtual, and some exceptions. David Miller suggested to define a new device flag, set in alloc_netdev_mq() (so that most devices set it at init time), and carefuly unset in devices which dont want a NULL skb->dst in their ndo_start_xmit(). List of devices that must clear this flag is : - loopback device, because it calls netif_rx() and quoting Patrick : "ip_route_input() doesn't accept loopback addresses, so loopback packets already need to have a dst_entry attached." - appletalk/ipddp.c : needs skb->dst in its xmit function - And all devices that call again dev_queue_xmit() from their xmit function (as some classifiers need skb->dst) : bonding, vlan, macvlan, eql, ifb, hdlc_fr Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-21netdev: add more functions to netdevice opsStephen Hemminger1-2/+2
This patch moves neigh_setup and hard_start_xmit into the network device ops structure. For bisection, fix all the previously converted drivers as well. Bonding driver took the biggest hit on this. Added a prefetch of the hard_start_xmit in the fast path to try and reduce any impact this would have. Signed-off-by: Stephen Hemminger <shemminger@vyatta.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-20ifb: convert to net_device_opsStephen Hemminger1-3/+8
Convert to new network device ops interface. Signed-off-by: Stephen Hemminger <shemminger@vyatta.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-08-01netdev: Fix lockdep warnings in multiqueue configurations.David S. Miller1-5/+7
When support for multiple TX queues were added, the netif_tx_lock() routines we converted to iterate over all TX queues and grab each queue's spinlock. This causes heartburn for lockdep and it's not a healthy thing to do with lots of TX queues anyways. So modify this to use a top-level lock and a "frozen" state for the individual TX queues. Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-18pkt_sched: Kill netdev_queue lock.David S. Miller1-20/+0
We can simply use the qdisc->q.lock for all of the qdisc tree synchronization. Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-18netdev: Allocate multiple queues for TX.David S. Miller1-3/+9
alloc_netdev_mq() now allocates an array of netdev_queue structures for TX, based upon the queue_count argument. Furthermore, all accesses to the TX queues are now vectored through the netdev_get_tx_queue() and netdev_for_each_tx_queue() interfaces. This makes it easy to grep the tree for all things that want to get to a TX queue of a net device. Problem spots which are not really multiqueue aware yet, and only work with one queue, can easily be spotted by grepping for all netdev_get_tx_queue() calls that pass in a zero index. Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-09netdev: The ingress_lock member is no longer needed.David S. Miller1-4/+4
Every qdisc is assosciated with a queue, and in the case of ingress qdiscs that will now be netdev->rx_queue so using that queue's lock is the thing to do. Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-09netdev: Move queue_lock into struct netdev_queue.David S. Miller1-4/+4
The lock is now an attribute of the device queue. One thing to notice is that "suspicious" places emerge which will need specific training about multiple queue handling. They are so marked with explicit "netdev->rx_queue" and "netdev->tx_queue" references. Signed-off-by: David S. Miller <davem@davemloft.net>
2008-03-21[NET] ifb: set separate lockdep classes for queue locksJarek Poplawski1-0/+15
[ 10.536424] ======================================================= [ 10.536424] [ INFO: possible circular locking dependency detected ] [ 10.536424] 2.6.25-rc3-devel #3 [ 10.536424] ------------------------------------------------------- [ 10.536424] swapper/0 is trying to acquire lock: [ 10.536424] (&dev->queue_lock){-+..}, at: [<c0299b4a>] dev_queue_xmit+0x175/0x2f3 [ 10.536424] [ 10.536424] but task is already holding lock: [ 10.536424] (&p->tcfc_lock){-+..}, at: [<f8a67154>] tcf_mirred+0x20/0x178 [act_mirred] [ 10.536424] [ 10.536424] which lock already depends on the new lock. lockdep warns of locking order while using ifb with sch_ingress and act_mirred: ingress_lock, tcfc_lock, queue_lock (usually queue_lock is at the beginning). This patch is only to tell lockdep that ifb is a different device (e.g. from eth) and has its own pair of queue locks. (This warning is a false-positive in common scenario of using ifb; yet there are possible situations, when this order could be dangerous; lockdep should warn in such a case.) (With suggestions by David S. Miller) Reported-and-tested-by: Denys Fedoryshchenko <denys@visp.net.lb> Signed-off-by: Jarek Poplawski <jarkao2@gmail.com> Acked-by: Jamal Hadi Salim <hadi@cyberus.ca> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-11[NET] drivers/net: statistics cleanup #1 -- save memory and shrink codeJeff Garzik1-18/+2
We now have struct net_device_stats embedded in struct net_device, and the default ->get_stats() hook does the obvious thing for us. Run through drivers/net/* and remove the driver-local storage of statistics, and driver-local ->get_stats() hook where applicable. This was just the low-hanging fruit in drivers/net; plenty more drivers remain to be updated. [ Resolved conflicts with napi_struct changes and fix sunqe build regression... -DaveM ] Signed-off-by: Jeff Garzik <jeff@garzik.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-11[NET]: Nuke SET_MODULE_OWNER macro.Ralf Baechle1-1/+0
It's been a useless no-op for long enough in 2.6 so I figured it's time to remove it. The number of people that could object because they're maintaining unified 2.4 and 2.6 drivers is probably rather small. [ Handled drivers added by netdev tree and some missed IRDA cases... -DaveM ] Signed-off-by: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Jeff Garzik <jeff@garzik.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-11[NET]: Make the device list and device lookups per namespace.Eric W. Biederman1-1/+2
This patch makes most of the generic device layer network namespace safe. This patch makes dev_base_head a network namespace variable, and then it picks up a few associated variables. The functions: dev_getbyhwaddr dev_getfirsthwbytype dev_get_by_flags dev_get_by_name __dev_get_by_name dev_get_by_index __dev_get_by_index dev_ioctl dev_ethtool dev_load wireless_process_ioctl were modified to take a network namespace argument, and deal with it. vlan_ioctl_set and brioctl_set were modified so their hooks will receive a network namespace argument. So basically anthing in the core of the network stack that was affected to by the change of dev_base was modified to handle multiple network namespaces. The rest of the network stack was simply modified to explicitly use &init_net the initial network namespace. This can be fixed when those components of the network stack are modified to handle multiple network namespaces. For now the ifindex generator is left global. Fundametally ifindex numbers are per namespace, or else we will have corner case problems with migration when we get that far. At the same time there are assumptions in the network stack that the ifindex of a network device won't change. Making the ifindex number global seems a good compromise until the network stack can cope with ifindex changes when you change namespaces, and the like. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-07-12[RTNETLINK]: rtnl_link: allow specifying initial device addressPatrick McHardy1-0/+12
Drivers need to validate the initial addresses in their netlink attribute validation function or manually reject them if they can't support this. Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-07-12[RTNETLINK]: rtnl_link API simplificationPatrick McHardy1-52/+6
All drivers need to unregister their devices in the module unload function. While doing so they must hold the rtnl and atomically unregister the rtnl_link ops as well. This makes the rtnl_link_unregister function that takes the rtnl itself completely useless. Provide default newlink/dellink functions, make __rtnl_link_unregister and rtnl_link_unregister unregister all devices with matching rtnl_link_ops and change the existing users to take advantage of that. Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-07-11[IFB]: Use rtnl_link APIPatrick McHardy1-20/+60
Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-07-11[IFB]: Keep ifb devices on listPatrick McHardy1-15/+21
Use a list instead of an array to allow creating new devices. Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-03-29[IFB]: Fix crash on input device removalPatrick McHardy1-22/+13
The input_device pointer is not refcounted, which means the device may disappear while packets are queued, causing a crash when ifb passes packets with a stale skb->dev pointer to netif_rx(). Fix by storing the interface index instead and do a lookup where neccessary. Signed-off-by: Patrick McHardy <kaber@trash.net> Acked-by: Jamal Hadi Salim <hadi@cyberus.ca> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-01-31Revert "net: ifb error path loop fix"Linus Torvalds1-1/+2
This reverts commit 0c0b3ae68ec93b1db5c637d294647d1cca0df763. Quoth David: "Jeff, please revert It's wrong. We had a lengthy analysis of this piece of code several months ago, and it is correct. Consider, if we run the loop and we get an error the following happens: 1) attempt of ifb_init_one(i) fails, therefore we should not try to "ifb_free_one()" on "i" since it failed 2) the loop iteration first increments "i", then it check for error Therefore we must decrement "i" twice before the first free during the cleanup. One to "undo" the for() loop increment, and one to "skip" the ifb_init_one() case which failed." Reported-by: David Miller <davem@davemloft.net> Acked-by: Jeff Garzik <jgarzik@pobox.com> Cc: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-01-30net: ifb error path loop fixMariusz Kozlowski1-2/+1
On error we should start freeing resources at [i-1] not [i-2]. Signed-off-by: Mariusz Kozlowski <m.kozlowski@tuxland.pl> Cc: Jeff Garzik <jeff@garzik.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Jeff Garzik <jeff@garzik.org>
2007-01-04[NET]: ifb double-counts packetsdean gaudet1-2/+2
Signed-off-by: dean gaudet <dean@arctic.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2006-10-03[PATCH] pr_debug: ifb: replace missing comma to separate pr_debug argumentsZach Brown1-2/+2
ifb: replace missing comma to separate pr_debug arguments Signed-off-by: Zach Brown <zach.brown@oracle.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-13drivers/net: Trim trailing whitespaceJeff Garzik1-21/+21
Signed-off-by: Jeff Garzik <jeff@garzik.org>
2006-07-22[IFB] After ifb_init_one() failed, i is increased. DecreaseNicolas Dichtel1-0/+1
It before entering in the loop for freeing the other ifb devices. Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com> Acked-by: Jamal Hadi Salim <hadi@cyberus.ca> Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-30Remove obsolete #include <linux/config.h>Jörn Engel1-1/+0
Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de> Signed-off-by: Adrian Bunk <bunk@stusta.de>
2006-06-18[NET]: Add netif_tx_lockHerbert Xu1-5/+5
Various drivers use xmit_lock internally to synchronise with their transmission routines. They do so without setting xmit_lock_owner. This is fine as long as netpoll is not in use. With netpoll it is possible for deadlocks to occur if xmit_lock_owner isn't set. This is because if a printk occurs while xmit_lock is held and xmit_lock_owner is not set can cause netpoll to attempt to take xmit_lock recursively. While it is possible to resolve this by getting netpoll to use trylock, it is suboptimal because netpoll's sole objective is to maximise the chance of getting the printk out on the wire. So delaying or dropping the message is to be avoided as much as possible. So the only alternative is to always set xmit_lock_owner. The following patch does this by introducing the netif_tx_lock family of functions that take care of setting/unsetting xmit_lock_owner. I renamed xmit_lock to _xmit_lock to indicate that it should not be used directly. I didn't provide irq versions of the netif_tx_lock functions since xmit_lock is meant to be a BH-disabling lock. This is pretty much a straight text substitution except for a small bug fix in winbond. It currently uses netif_stop_queue/spin_unlock_wait to stop transmission. This is unsafe as an IRQ can potentially wake up the queue. So it is safer to use netif_tx_disable. The hamradio bits used spin_lock_irq but it is unnecessary as xmit_lock must never be taken in an IRQ handler. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2006-02-24[NET]: Increase default IFB device count.Richard Lucassen1-1/+1
The most usable number of ifb devices is 2. Change the default to 2. Signed-off-by: Richard Lucassen <spamtrap@lucassen.org> Signed-off-by: Jamal Hadi Salim <hadi@cyberus.ca> Signed-off-by: David S. Miller <davem@davemloft.net>
2006-01-10[NET]: Add IFB (Intermediate Functional Block) network device.Jamal Hadi Salim1-0/+294
A new device to do intermidiate functional block in a system shared manner. To use the new functionality, you need to turn on qos/classifier actions. The new functionality can be grouped as: 1) qdiscs/policies that are per device as opposed to system wide. ifb allows for a device which can be redirected to thus providing an impression of sharing. 2) Allows for queueing incoming traffic for shaping instead of dropping. Packets are redirected to this device using tc/action mirred redirect construct. If they are sent to it by plain routing instead then they will merely be dropped and the stats would indicate that. Signed-off-by: Jamal Hadi Salim <hadi@cyberus.ca> Signed-off-by: David S. Miller <davem@davemloft.net>