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>
diff --git a/net/sched/sch_htb.c b/net/sched/sch_htb.c
index aea942c..6d16b9b 100644
--- a/net/sched/sch_htb.c
+++ b/net/sched/sch_htb.c
@@ -103,7 +103,7 @@
u32 prio; /* these two are used only by leaves... */
int quantum; /* but stored for parent-to-leaf return */
- struct tcf_proto *filter_list; /* class attached filters */
+ struct tcf_proto __rcu *filter_list; /* class attached filters */
int filter_cnt;
int refcnt; /* usage count of this class */
@@ -153,7 +153,7 @@
int rate2quantum; /* quant = rate / rate2quantum */
/* filters for qdisc itself */
- struct tcf_proto *filter_list;
+ struct tcf_proto __rcu *filter_list;
#define HTB_WARN_TOOMANYEVENTS 0x1
unsigned int warned; /* only one warning */
@@ -223,9 +223,9 @@
if (cl->level == 0)
return cl;
/* Start with inner filter chain if a non-leaf class is selected */
- tcf = cl->filter_list;
+ tcf = rcu_dereference_bh(cl->filter_list);
} else {
- tcf = q->filter_list;
+ tcf = rcu_dereference_bh(q->filter_list);
}
*qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
@@ -251,7 +251,7 @@
return cl; /* we hit leaf; return it */
/* we have got inner class; apply inner filter chain */
- tcf = cl->filter_list;
+ tcf = rcu_dereference_bh(cl->filter_list);
}
/* classification failed; try to use default class */
cl = htb_find(TC_H_MAKE(TC_H_MAJ(sch->handle), q->defcls), sch);
@@ -1519,11 +1519,12 @@
return err;
}
-static struct tcf_proto **htb_find_tcf(struct Qdisc *sch, unsigned long arg)
+static struct tcf_proto __rcu **htb_find_tcf(struct Qdisc *sch,
+ unsigned long arg)
{
struct htb_sched *q = qdisc_priv(sch);
struct htb_class *cl = (struct htb_class *)arg;
- struct tcf_proto **fl = cl ? &cl->filter_list : &q->filter_list;
+ struct tcf_proto __rcu **fl = cl ? &cl->filter_list : &q->filter_list;
return fl;
}