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authorJohn Fastabend <john.fastabend@gmail.com>2014-09-12 20:05:27 -0700
committerDavid S. Miller <davem@davemloft.net>2014-09-13 12:30:25 -0400
commit25d8c0d55f241ce2d360df1bea48e23a55836ee6 (patch)
treec0aca67607e7ce560a4a2cebef5fb6d55adf4112 /net/sched/sch_atm.c
parentnet: qdisc: use rcu prefix and silence sparse warnings (diff)
downloadlinux-dev-25d8c0d55f241ce2d360df1bea48e23a55836ee6.tar.xz
linux-dev-25d8c0d55f241ce2d360df1bea48e23a55836ee6.zip
net: rcu-ify tcf_proto
rcu'ify tcf_proto this allows calling tc_classify() without holding any locks. Updaters are protected by RTNL. This patch prepares the core net_sched infrastracture for running the classifier/action chains without holding the qdisc lock however it does nothing to ensure cls_xxx and act_xxx types also work without locking. Additional patches are required to address the fall out. Signed-off-by: John Fastabend <john.r.fastabend@intel.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sched/sch_atm.c')
-rw-r--r--net/sched/sch_atm.c20
1 files changed, 11 insertions, 9 deletions
diff --git a/net/sched/sch_atm.c b/net/sched/sch_atm.c
index 8449b337f9e3..c398f9c3dbdd 100644
--- a/net/sched/sch_atm.c
+++ b/net/sched/sch_atm.c
@@ -41,7 +41,7 @@
struct atm_flow_data {
struct Qdisc *q; /* FIFO, TBF, etc. */
- struct tcf_proto *filter_list;
+ struct tcf_proto __rcu *filter_list;
struct atm_vcc *vcc; /* VCC; NULL if VCC is closed */
void (*old_pop)(struct atm_vcc *vcc,
struct sk_buff *skb); /* chaining */
@@ -273,7 +273,7 @@ static int atm_tc_change(struct Qdisc *sch, u32 classid, u32 parent,
error = -ENOBUFS;
goto err_out;
}
- flow->filter_list = NULL;
+ RCU_INIT_POINTER(flow->filter_list, NULL);
flow->q = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops, classid);
if (!flow->q)
flow->q = &noop_qdisc;
@@ -311,7 +311,7 @@ static int atm_tc_delete(struct Qdisc *sch, unsigned long arg)
pr_debug("atm_tc_delete(sch %p,[qdisc %p],flow %p)\n", sch, p, flow);
if (list_empty(&flow->list))
return -EINVAL;
- if (flow->filter_list || flow == &p->link)
+ if (rcu_access_pointer(flow->filter_list) || flow == &p->link)
return -EBUSY;
/*
* Reference count must be 2: one for "keepalive" (set at class
@@ -345,7 +345,8 @@ static void atm_tc_walk(struct Qdisc *sch, struct qdisc_walker *walker)
}
}
-static struct tcf_proto **atm_tc_find_tcf(struct Qdisc *sch, unsigned long cl)
+static struct tcf_proto __rcu **atm_tc_find_tcf(struct Qdisc *sch,
+ unsigned long cl)
{
struct atm_qdisc_data *p = qdisc_priv(sch);
struct atm_flow_data *flow = (struct atm_flow_data *)cl;
@@ -369,11 +370,12 @@ static int atm_tc_enqueue(struct sk_buff *skb, struct Qdisc *sch)
flow = NULL;
if (TC_H_MAJ(skb->priority) != sch->handle ||
!(flow = (struct atm_flow_data *)atm_tc_get(sch, skb->priority))) {
+ struct tcf_proto *fl;
+
list_for_each_entry(flow, &p->flows, list) {
- if (flow->filter_list) {
- result = tc_classify_compat(skb,
- flow->filter_list,
- &res);
+ fl = rcu_dereference_bh(flow->filter_list);
+ if (fl) {
+ result = tc_classify_compat(skb, fl, &res);
if (result < 0)
continue;
flow = (struct atm_flow_data *)res.class;
@@ -544,7 +546,7 @@ static int atm_tc_init(struct Qdisc *sch, struct nlattr *opt)
if (!p->link.q)
p->link.q = &noop_qdisc;
pr_debug("atm_tc_init: link (%p) qdisc %p\n", &p->link, p->link.q);
- p->link.filter_list = NULL;
+ RCU_INIT_POINTER(p->link.filter_list, NULL);
p->link.vcc = NULL;
p->link.sock = NULL;
p->link.classid = sch->handle;