Commit Graph

45 Commits

Author SHA1 Message Date
Michał Mirosław
34324dc2bf net: remove NETIF_F_NO_CSUM feature bit
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>
2011-11-16 17:43:12 -05:00
Neil Horman
550fd08c2c net: Audit drivers to identify those needing IFF_TX_SKB_SHARING cleared
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>
2011-07-27 22:39:30 -07:00
stephen hemminger
3b0c9cbb6e ifb: convert to 64 bit stats
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>
2011-06-21 15:55:09 -07:00
Alexey Dobriyan
a6b7a40786 net: remove interrupt.h inclusion from netdevice.h
* 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>
2011-06-06 22:55:11 -07:00
Jiri Pirko
1c5cae815d net: call dev_alloc_name from register_netdevice
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
84c49d8c3e

Signed-off-by: Jiri Pirko <jpirko@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2011-05-05 10:57:45 -07:00
Eric Dumazet
39980292fd ifb: add performance flags
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>
2011-01-03 12:43:10 -08:00
Eric Dumazet
1a75972c61 ifb: use netif_receive_skb() instead of netif_rx()
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>
2010-12-19 21:44:30 -08:00
Eric Dumazet
7edc3453e5 ifb: fix a lockdep splat
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>
2010-12-16 14:54:52 -08:00
Changli Gao
957fca95e3 ifb: use the lockless variants of skb_queue
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>
2010-12-10 14:34:34 -08:00
Changli Gao
c6350362cb ifb: remove unused macro TX_TIMEOUT
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>
2010-12-10 14:34:34 -08:00
Changli Gao
e1f9150502 ifb: remove the useless debug stats
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>
2010-12-10 14:34:33 -08:00
Changli Gao
75c1c82566 ifb: goto resched directly if error happens and dp->tq isn't empty
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>
2010-12-08 09:45:34 -08:00
Eric Dumazet
1ae5dc342a net: trans_start cleanups
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>
2010-05-10 05:01:31 -07:00
Eric Dumazet
8964be4a9a net: rename skb->iif to skb->skb_iif
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>
2009-11-20 15:35:04 -08:00
Eric Dumazet
05e8689c9a ifb: RCU locking avoids touching dev refcount
Avoids touching dev refcount in hotpath

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-11-01 23:55:12 -08:00
Eric Dumazet
db51914424 ifb: should not use __dev_get_by_index() without locks
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>
2009-10-22 21:54:19 -07:00
Stephen Hemminger
424efe9caf netdev: convert pseudo drivers to netdev_tx_t
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>
2009-09-01 01:13:40 -07:00
Patrick McHardy
ec634fe328 net: convert remaining non-symbolic return values in ndo_start_xmit() functions
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>
2009-07-05 19:23:38 -07:00
Eric Dumazet
93f154b594 net: release dst entry in dev_hard_start_xmit()
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>
2009-05-18 22:19:19 -07:00
Stephen Hemminger
008298231a netdev: add more functions to netdevice ops
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>
2008-11-20 20:14:53 -08:00
Stephen Hemminger
8dfcdf342d ifb: convert to net_device_ops
Convert to new network device ops interface.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-19 22:42:38 -08:00
David S. Miller
c3f26a269c netdev: Fix lockdep warnings in multiqueue configurations.
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>
2008-07-31 16:58:50 -07:00
David S. Miller
8387400092 pkt_sched: Kill netdev_queue lock.
We can simply use the qdisc->q.lock for all of the
qdisc tree synchronization.

Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-17 19:21:30 -07:00
David S. Miller
e8a0464cc9 netdev: Allocate multiple queues for TX.
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>
2008-07-17 19:21:00 -07:00
David S. Miller
555353cfa1 netdev: The ingress_lock member is no longer needed.
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>
2008-07-08 17:33:13 -07:00
David S. Miller
dc2b48475a netdev: Move queue_lock into struct netdev_queue.
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>
2008-07-08 17:18:23 -07:00
Jarek Poplawski
94833dfb8c [NET] ifb: set separate lockdep classes for queue locks
[   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>
2008-03-20 17:05:13 -07:00
Jeff Garzik
09f75cd7bf [NET] drivers/net: statistics cleanup #1 -- save memory and shrink code
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>
2007-10-10 16:51:16 -07:00
Ralf Baechle
10d024c1b2 [NET]: Nuke SET_MODULE_OWNER macro.
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>
2007-10-10 16:51:13 -07:00
Eric W. Biederman
881d966b48 [NET]: Make the device list and device lookups per namespace.
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>
2007-10-10 16:49:10 -07:00
Patrick McHardy
0e06877c6f [RTNETLINK]: rtnl_link: allow specifying initial device address
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>
2007-07-11 19:45:36 -07:00
Patrick McHardy
2d85cba2b2 [RTNETLINK]: rtnl_link API simplification
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 19:45:33 -07:00
Patrick McHardy
9ba2cd6560 [IFB]: Use rtnl_link API
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-07-10 22:14:37 -07:00
Patrick McHardy
62b7ffcaaa [IFB]: Keep ifb devices on list
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>
2007-07-10 22:14:36 -07:00
Patrick McHardy
c01003c205 [IFB]: Fix crash on input device removal
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>
2007-03-29 11:46:52 -07:00
Linus Torvalds
bcdddfb66c Revert "net: ifb error path loop fix"
This reverts commit 0c0b3ae68e.

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>
2007-01-30 14:11:12 -08:00
Mariusz Kozlowski
0c0b3ae68e net: ifb error path loop fix
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>
2007-01-30 09:36:01 -05:00
dean gaudet
3136dcb3cd [NET]: ifb double-counts packets
Signed-off-by: dean gaudet <dean@arctic.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-01-03 18:38:08 -08:00
Zach Brown
8057de64fd [PATCH] pr_debug: ifb: replace missing comma to separate pr_debug arguments
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>
2006-10-03 08:04:19 -07:00
Jeff Garzik
6aa20a2235 drivers/net: Trim trailing whitespace
Signed-off-by: Jeff Garzik <jeff@garzik.org>
2006-09-13 13:24:59 -04:00
Nicolas Dichtel
4a9c74e583 [IFB] After ifb_init_one() failed, i is increased. Decrease
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>
2006-07-21 14:56:02 -07:00
Jörn Engel
6ab3d5624e Remove obsolete #include <linux/config.h>
Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
2006-06-30 19:25:36 +02:00
Herbert Xu
932ff279a4 [NET]: Add netif_tx_lock
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>
2006-06-17 21:30:14 -07:00
Richard Lucassen
35eaa31e5d [NET]: Increase default IFB device count.
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>
2006-02-23 16:23:51 -08:00
Jamal Hadi Salim
253af4235d [NET]: Add IFB (Intermediate Functional Block) network device.
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>
2006-01-09 14:16:23 -08:00