Commit graph

94 commits

Author SHA1 Message Date
Jarek Poplawski
f7a54c13c7 pkt_sched: Use rcu_assign_pointer() to change dev_queue->qdisc
These pointers are RCU protected, so proper primitives should be used.

Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-08-27 02:22:07 -07:00
Jarek Poplawski
f6e0b239a2 pkt_sched: Fix qdisc list locking
Since some qdiscs call qdisc_tree_decrease_qlen() (so qdisc_lookup())
without rtnl_lock(), adding and deleting from a qdisc list needs
additional locking. This patch adds global spinlock qdisc_list_lock
and wrapper functions for modifying the list. It is considered as a
temporary solution until hfsc_dequeue(), netem_dequeue() and
tbf_dequeue() (or qdisc_tree_decrease_qlen()) are redone.

With feedback from Herbert Xu and David S. Miller.

Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-08-22 03:31:39 -07:00
David S. Miller
4d8863a29c pkt_sched: Don't hold qdisc lock over qdisc_destroy().
Based upon reports by Denys Fedoryshchenko, and feedback
and help from Jarek Poplawski and Herbert Xu.

We always either:

1) Never made an external reference to this qdisc.

or

2) Did a dev_deactivate() which purged all asynchronous
   references.

So do not lock the qdisc when we call qdisc_destroy(),
it's illegal anyways as when we drop the lock this is
free'd memory.

Signed-off-by: David S. Miller <davem@davemloft.net>
2008-08-18 21:06:19 -07:00
David S. Miller
1e0d5a5747 pkt_sched: No longer destroy qdiscs from RCU.
We can now kill them synchronously with all of the
previous dev_deactivate() cures.

This makes netdev destruction and shutdown saner as
the qdiscs hold references to the device.

Signed-off-by: David S. Miller <davem@davemloft.net>
2008-08-17 22:31:26 -07:00
David S. Miller
4335cd2da1 pkt_sched: Simplify dev_deactivate() polling loop.
The condition under which the previous qdisc has no more references
after we've attached &noop_qdisc is that both RUNNING and SCHED
are both seen clear while holding the root lock.

So just make specifically that check in the polling loop, instead
of this overly complex "check without then check with lock held"
sequence.

Signed-off-by: David S. Miller <davem@davemloft.net>
2008-08-17 21:58:07 -07:00
David S. Miller
a9312ae893 pkt_sched: Add 'deactivated' state.
This new state lets dev_deactivate() mark a qdisc as having been
deactivated.

dev_queue_xmit() and ing_filter() check for this bit and do not
try to process the qdisc if the bit is set.

dev_deactivate() polls the qdisc after setting the bit, waiting
for both __QDISC_STATE_RUNNING and __QDISC_STATE_SCHED to clear.

This isn't perfect yet, but subsequent changesets will make it so.
This part is just one piece of the puzzle.

Signed-off-by: David S. Miller <davem@davemloft.net>
2008-08-17 21:51:03 -07:00
David S. Miller
b9a3b1102b pkt_sched: Fix queue quiescence testing in dev_deactivate().
Based upon discussions with Jarek P. and Herbert Xu.

First, we're testing the wrong qdisc.  We just reset the device
queue qdiscs to &noop_qdisc and checking it's state is completely
pointless here.

We want to wait until the previous qdisc that was sitting at
the ->qdisc pointer is not busy any more.  And that would be
->qdisc_sleeping.

Because of how we propagate the samples qdisc pointer down into
qdisc_run and friends via per-cpu ->output_queue and netif_schedule,
we have to wait also for the __QDISC_STATE_SCHED bit to clear as
well.

Signed-off-by: David S. Miller <davem@davemloft.net>
2008-08-13 15:18:38 -07:00
David S. Miller
5fb662297b pkt_sched: Use qdisc_lock() on already sampled root qdisc.
Based upon a bug report by Jeff Kirsher.

Don't use qdisc_root_lock() in these cases as the root
qdisc could have been changed, and we'd thus lock the
wrong object.

Tested by Emil S Tantilov who confirms that this seems
to fix the problem.

Signed-off-by: David S. Miller <davem@davemloft.net>
2008-08-02 20:02:43 -07:00
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
8d50b53d66 pkt_sched: Fix OOPS on ingress qdisc add.
Bug report from Steven Jan Springl:

	Issuing the following command causes a kernel oops:
		tc qdisc add dev eth0 handle ffff: ingress

The problem mostly stems from all of the special case handling of
ingress qdiscs.

So, to fix this, do the grafting operation the same way we do for TX
qdiscs.  Which means that dev_activate() and dev_deactivate() now do
the "qdisc_sleeping <--> qdisc" transitions on dev->rx_queue too.

Future simplifications are possible now, mainly because it is
impossible for dev_queue->{qdisc,qdisc_sleeping} to be NULL.  There
are NULL checks all over to handle the ingress qdisc special case
that used to exist before this commit.

Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-30 02:44:25 -07:00
Ilpo Järvinen
547b792cac net: convert BUG_TRAP to generic WARN_ON
Removes legacy reinvent-the-wheel type thing. The generic
machinery integrates much better to automated debugging aids
such as kerneloops.org (and others), and is unambiguous due to
better naming. Non-intuively BUG_TRAP() is actually equal to
WARN_ON() rather than BUG_ON() though some might actually be
promoted to BUG_ON() but I left that to future.

I could make at least one BUILD_BUG_ON conversion.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-25 21:43:18 -07:00
David S. Miller
cffe1c5d7a pkt_sched: Fix locking in shutdown_scheduler_queue()
Qdisc locks need to be held with BH disabled.

Tested-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-25 01:25:04 -07:00
Arjan van de Ven
6579e57b31 net: Print the module name as part of the watchdog message
As suggested by Dave:

This patch adds a function to get the driver name from a struct net_device,
and consequently uses this in the watchdog timeout handler to print as 
part of the message. 

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-21 13:31:48 -07:00
David S. Miller
d3678b463d Revert "pkt_sched: Make default qdisc nonshared-multiqueue safe."
This reverts commit a0c80b80e0.

After discussions with Jamal and Herbert on netdev, we should
provide at least minimal prioritization at the qdisc level
even in multiqueue situations.

Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-21 10:10:50 -07:00
Daniel Lezcano
c3ee84163e pkt_sched: Remove unused variable skb in dev_deactivate_queue function.
Removed unused variable 'skb' in the dev_deactivate_queue function

Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-21 09:18:07 -07:00
David S. Miller
3a682fbd73 pkt_sched: Fix build with NET_SCHED disabled.
The stab bits can't be referenced uniless the full
packet scheduler layer is enabled.

Reported by Stephen Rothwell.

Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-20 18:13:01 -07:00
Jussi Kivilinna
175f9c1bba net_sched: Add size table for qdiscs
Add size table functions for qdiscs and calculate packet size in
qdisc_enqueue().

Based on patch by Patrick McHardy
 http://marc.info/?l=linux-netdev&m=115201979221729&w=2

Signed-off-by: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-20 00:08:47 -07:00
David S. Miller
30ee42be00 pkt_sched: Fix noqueue_qdisc initialization.
Like noop_qdisc, it needs a dummy backpointer and
explicit qdisc->q.lock initialization.

Based upon a report by Stephen Hemminger.

Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-18 23:00:11 -07:00
David S. Miller
3072367300 pkt_sched: Manage qdisc list inside of root qdisc.
Idea is from Patrick McHardy.

Instead of managing the list of qdiscs on the device level, manage it
in the root qdisc of a netdev_queue.  This solves all kinds of
visibility issues during qdisc destruction.

The way to iterate over all qdiscs of a netdev_queue is to visit
the netdev_queue->qdisc, and then traverse it's list.

The only special case is to ignore builting qdiscs at the root when
dumping or doing a qdisc_lookup().  That was not needed previously
because builtin qdiscs were not added to the device's qdisc_list.

Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-18 22:50:15 -07:00
David S. Miller
a0c80b80e0 pkt_sched: Make default qdisc nonshared-multiqueue safe.
Instead of 'pfifo_fast' we have just plain 'fifo_fast'.
No priority queues, just a straight FIFO.

This is necessary in order to legally have a seperate
qdisc per queue in multi-TX-queue setups, and thus get
full parallelization.

Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-17 19:21:33 -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
c7e4f3bbb4 pkt_sched: Kill qdisc_lock_tree and qdisc_unlock_tree.
No longer used.

Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-17 19:21:29 -07:00
David S. Miller
ead81cc5fc netdevice: Move qdisc_list back into net_device proper.
And give it it's own lock.

Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-17 19:21:26 -07:00
David S. Miller
17715e62a5 pkt_sched: Use per-queue locking in shutdown_scheduler_queue.
This eliminates another qdisc_lock_tree user.

Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-17 19:21:23 -07:00
David S. Miller
8a34c5dc3a pkt_sched: Perform bulk of qdisc destruction in RCU.
This allows less strict control of access to the qdisc attached to a
netdev_queue.  It is even allowed to enqueue into a qdisc which is
in the process of being destroyed.  The RCU handler will toss out
those packets.

We will need this to handle sharing of a qdisc amongst multiple
TX queues.  In such a setup the lock has to be shared, so will
be inside of the qdisc itself.  At which point the netdev_queue
lock cannot be used to hard synchronize access to the ->qdisc
pointer.

One operation we have to keep inside of qdisc_destroy() is the list
deletion.  It is the only piece of state visible after the RCU quiesce
period, so we have to undo it early and under the appropriate locking.

The operations in the RCU handler do not need any looking because the
qdisc tree is no longer visible to anything at that point.

Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-17 19:21:22 -07:00
David S. Miller
16361127eb pkt_sched: dev_init_scheduler() does not need to lock qdisc tree.
We are registering the device, there is no way anyone can get
at this object's qdiscs yet in any meaningful way.

Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-17 19:21:21 -07:00
David S. Miller
37437bb2e1 pkt_sched: Schedule qdiscs instead of netdev_queue.
When we have shared qdiscs, packets come out of the qdiscs
for multiple transmit queues.

Therefore it doesn't make any sense to schedule the transmit
queue when logically we cannot know ahead of time the TX
queue of the SKB that the qdisc->dequeue() will give us.

Just for sanity I added a BUG check to make sure we never
get into a state where the noop_qdisc is scheduled.

Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-17 19:21:20 -07:00
David S. Miller
7698b4fcab pkt_sched: Add and use qdisc_root() and qdisc_root_lock().
When code wants to lock the qdisc tree state, the logic
operation it's doing is locking the top-level qdisc that
sits of the root of the netdev_queue.

Add qdisc_root_lock() to represent this and convert the
easiest cases.

In order for this to work out in all cases, we have to
hook up the noop_qdisc to a dummy netdev_queue.

Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-17 19:21:19 -07:00
David S. Miller
e2627c8c22 pkt_sched: Make QDISC_RUNNING a qdisc state.
Currently it is associated with a netdev_queue, but when we have
qdisc sharing that no longer makes any sense.

Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-17 19:21:18 -07:00
David S. Miller
d3b753db7c pkt_sched: Move gso_skb into Qdisc.
We liberate any dangling gso_skb during qdisc destruction.

It really only matters for the root qdisc.  But when qdiscs
can be shared by multiple netdev_queue objects, we can't
have the gso_skb in the netdev_queue any more.

Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-17 19:21:18 -07:00
David S. Miller
fd2ea0a79f net: Use queue aware tests throughout.
This effectively "flips the switch" by making the core networking
and multiqueue-aware drivers use the new TX multiqueue structures.

Non-multiqueue drivers need no changes.  The interfaces they use such
as netif_stop_queue() degenerate into an operation on TX queue zero.
So everything "just works" for them.

Code that really wants to do "X" to all TX queues now invokes a
routine that does so, such as netif_tx_wake_all_queues(),
netif_tx_stop_all_queues(), etc.

pktgen and netpoll required a little bit more surgery than the others.

In particular the pktgen changes, whilst functional, could be largely
improved.  The initial check in pktgen_xmit() will sometimes check the
wrong queue, which is mostly harmless.  The thing to do is probably to
invoke fill_packet() earlier.

The bulk of the netpoll changes is to make the code operate solely on
the TX queue indicated by by the SKB queue mapping.

Setting of the SKB queue mapping is entirely confined inside of
net/core/dev.c:dev_pick_tx().  If we end up needing any kind of
special semantics (drops, for example) it will be implemented here.

Finally, we now have a "real_num_tx_queues" which is where the driver
indicates how many TX queues are actually active.

With IGB changes from Jeff Kirsher.

Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-17 19:21:07 -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
79d16385c7 netdev: Move atomic queue state bits into netdev_queue.
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-08 23:14:46 -07:00
David S. Miller
c773e847ea netdev: Move _xmit_lock and xmit_lock_owner into netdev_queue.
Accesses are mostly structured such that when there are multiple TX
queues the code transformations will be a little bit simpler.

Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-08 23:13:53 -07:00
David S. Miller
eb6aafe3f8 pkt_sched: Make qdisc_run take a netdev_queue.
This allows us to use this calling convention all the way down into
qdisc_restart().

Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-08 23:12:38 -07:00
David S. Miller
86d804e10a netdev: Make netif_schedule() routines work with netdev_queue objects.
Only plain netif_schedule() remains taking a net_device, mostly as a
compatability item while we transition the rest of these interfaces.

Everything else calls netif_schedule_queue() or __netif_schedule(),
both of which take a netdev_queue pointer.

Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-08 23:11:25 -07:00
David S. Miller
970565bbad netdev: Move gso_skb into netdev_queue.
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-08 23:10:33 -07:00
David S. Miller
68dfb42798 pkt_sched: Kill stats_lock member of struct Qdisc.
It is always equal to qdisc->dev_queue->lock

Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-08 22:57:31 -07:00
David S. Miller
b0e1e6462d netdev: Move rest of qdisc state into struct netdev_queue
Now qdisc, qdisc_sleeping, and qdisc_list also live there.

Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-08 17:42:10 -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
David S. Miller
5ce2d488fe pkt_sched: Remove 'dev' member of struct Qdisc.
It can be obtained via the netdev_queue.  So create a helper routine,
qdisc_dev(), to make the transformations nicer looking.

Now, qdisc_alloc() now no longer needs a net_device pointer argument.

Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-08 17:06:30 -07:00
David S. Miller
bb949fbd18 netdev: Create netdev_queue abstraction.
A netdev_queue is an entity managed by a qdisc.

Currently there is one RX and one TX queue, and a netdev_queue merely
contains a backpointer to the net_device.

The Qdisc struct is augmented with a netdev_queue pointer as well.

Eventually the 'dev' Qdisc member will go away and we will have the
resulting hierarchy:

	net_device --> netdev_queue --> Qdisc

Also, qdisc_alloc() and qdisc_create_dflt() now take a netdev_queue
pointer argument.

Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-08 16:55:56 -07:00
WANG Cong
01e123d79a pkt_sched: ERR_PTR() ususally encodes an negative errno, not positive.
Note, in the following patch, 'err' is initialized as:

int err = -ENOBUFS;

Signed-off-by: WANG Cong <wcong@critical-links.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-06-27 19:51:35 -07:00
Arjan van de Ven
b4192bbd85 net: Add a WARN_ON_ONCE() to the transmit timeout function
WARN_ON_ONCE() gives a stack trace including the full module list.
Having this in the kernel dump for the timeout case in the
generic netdev watchdog will help us see quicker which driver
is involved. It also allows us to collect statistics 
and patterns in terms of which drivers have this event occuring.

Suggested by Andrew Morton

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-05-02 16:21:07 -07:00
Herbert Xu
2ba2506ca7 [NET]: Add preemption point in qdisc_run
The qdisc_run loop is currently unbounded and runs entirely in a
softirq.  This is bad as it may create an unbounded softirq run.

This patch fixes this by calling need_resched and breaking out if
necessary.

It also adds a break out if the jiffies value changes since that would
indicate we've been transmitting for too long which starves other
softirqs.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-03-28 16:25:26 -07:00
Patrick McHardy
1e90474c37 [NET_SCHED]: Convert packet schedulers from rtnetlink to new netlink API
Convert packet schedulers to use the netlink API. Unfortunately a gradual
conversion is not possible without breaking compilation in the middle or
adding lots of casts, so this patch converts them all in one step. The
patch has been mostly generated automatically with some minor edits to
at least allow seperate conversion of classifiers and actions.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-01-28 15:11:10 -08:00
Patrick McHardy
62e3ba1b55 [NET_SCHED]: Move EXPORT_SYMBOL next to exported symbol
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-01-28 15:11:07 -08:00
Eric Dumazet
9a429c4983 [NET]: Add some acquires/releases sparse annotations.
Add __acquires() and __releases() annotations to suppress some sparse
warnings.

example of warnings :

net/ipv4/udp.c:1555:14: warning: context imbalance in 'udp_seq_start' - wrong
count at exit
net/ipv4/udp.c:1571:13: warning: context imbalance in 'udp_seq_stop' -
unexpected unlock

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-01-28 15:00:31 -08:00
Eric Dumazet
20fea08b5f [NET]: Move Qdisc_class_ops and Qdisc_ops in appropriate sections.
Qdisc_class_ops are const, and Qdisc_ops are mostly read.

Using "const" and "__read_mostly" qualifiers helps to reduce false
sharing.

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-01-28 14:53:58 -08:00