linux-stable.git/net/sched/cls_basic.c, branch linux-3.18.y

net: sched: do not use tcf_proto 'tp' argument from call_rcu

2014-10-06T22:02:33+00:00

Using the tcf_proto pointer 'tp' from inside the classifiers callback
is not valid because it may have been cleaned up by another call_rcu
occuring on another CPU.

'tp' is currently being used by tcf_unbind_filter() in this patch we
move instances of tcf_unbind_filter outside of the call_rcu() context.
This is safe to do because any running schedulers will either read the
valid class field or it will be zeroed.

And all schedulers today when the class is 0 do a lookup using the
same call used by the tcf_exts_bind(). So even if we have a running
classifier hit the null class pointer it will do a lookup and get
to the same result. This is particularly fragile at the moment because
the only way to verify this is to audit the schedulers call sites.

Reported-by: Cong Wang 
Signed-off-by: John Fastabend 
Acked-by: Cong Wang 
Signed-off-by: David S. Miller

net: sched: remove tcf_proto from ematch calls

2014-10-06T22:02:32+00:00

This removes the tcf_proto argument from the ematch code paths that
only need it to reference the net namespace. This allows simplifying
qdisc code paths especially when we need to tear down the ematch
from an RCU callback. In this case we can not guarentee that the
tcf_proto structure is still valid.

Signed-off-by: John Fastabend 
Acked-by: Cong Wang 
Signed-off-by: David S. Miller

net_sched: remove the first parameter from tcf_exts_destroy()

2014-09-28T21:29:01+00:00

Cc: Jamal Hadi Salim 
Signed-off-by: Cong Wang 
Acked-by: Jamal Hadi Salim 
Signed-off-by: David S. Miller

net: sched: cls_basic use RCU

2014-09-13T16:30:25+00:00

Enable basic classifier for RCU.

Dereferencing tp->root may look a bit strange here but it is needed
by my accounting because it is allocated at init time and needs to
be kfree'd at destroy time. However because it may be referenced in
the classify() path we must wait an RCU grace period before free'ing
it. We use kfree_rcu() and rcu_ APIs to enforce this. This pattern
is used in all the classifiers.

Also the hgenerator can be incremented without concern because it
is always incremented under RTNL.

Signed-off-by: John Fastabend 
Acked-by: Eric Dumazet 
Signed-off-by: David S. Miller

sched, cls: check if we could overwrite actions when changing a filter

2014-04-28T03:42:39+00:00

When actions are attached to a filter, they are a part of the filter
itself, so when changing a filter we should allow to overwrite the actions
inside as well.

In my specific case, when I tried to _append_ a new action to an existing
filter which already has an action, I got EEXIST since kernel refused
to overwrite the existing one in kernel.

This patch checks if we are changing the filter checking NLM_F_CREATE flag
(Sigh, filters don't use NLM_F_REPLACE...) and then passes the boolean down
to actions. This fixes the problem above.

Cc: Jamal Hadi Salim 
Cc: David S. Miller 
Signed-off-by: Cong Wang 
Signed-off-by: Cong Wang 
Signed-off-by: Jamal Hadi Salim 
Signed-off-by: David S. Miller

net_sched: avoid casting void pointer

2014-01-13T19:50:15+00:00

tp->root is a void* pointer, no need to cast it.

Cc: Jamal Hadi Salim 
Cc: David S. Miller 
Signed-off-by: Cong Wang 
Acked-by: Jamal Hadi Salim 
Signed-off-by: David S. Miller

net_sched: add struct net pointer to tcf_proto_ops->dump

2014-01-13T19:50:14+00:00

It will be needed by the next patch.

Cc: Jamal Hadi Salim 
Cc: David S. Miller 
Signed-off-by: Cong Wang 
Signed-off-by: Jamal Hadi Salim 
Signed-off-by: David S. Miller

net_sched: cls: refactor out struct tcf_ext_map

2013-12-18T17:52:07+00:00

These information can be saved in tcf_exts, and this will
simplify the code.

Cc: Jamal Hadi Salim 
Cc: David S. Miller 
Signed-off-by: Cong Wang 
Signed-off-by: Jamal Hadi Salim 
Signed-off-by: David S. Miller

net_sched: act: use standard struct list_head

2013-12-18T17:52:07+00:00

Currently actions are chained by a singly linked list,
therefore it is a bit hard to add and remove a specific
entry. Convert it to struct list_head so that in the
latter patch we can remove an action without finding
its head.

Cc: Jamal Hadi Salim 
Cc: David S. Miller 
Signed-off-by: Cong Wang 
Signed-off-by: Jamal Hadi Salim 
Signed-off-by: David S. Miller

qdisc: basic classifier - remove unnecessary initialization

2013-09-30T19:47:43+00:00

err is set once, then first code resets it.
  err = tcf_exts_validate(...)

Signed-off-by: Stephen Hemminger 
Acked-by: Jamal Hadi Salim 
Signed-off-by: David S. Miller