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path: root/drivers/net/ifb.c
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2006-06-17[NET]: Add netif_tx_lockHerbert Xu
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>
2006-02-23[NET]: Increase default IFB device count.Richard Lucassen
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>
2006-01-09[NET]: Add IFB (Intermediate Functional Block) network device.Jamal Hadi Salim
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>