pkt_sched: remove unnecessary xchg() in packet classifiers
The use of xchg() hasn't been necessary since 2.2.something when proper
locking was added to packet schedulers. In the case of classifiers they
mostly weren't even necessary before that since they're mainly used
to assign a NULL pointer to the filter root in the ->destroy path;
the root is destroyed immediately after that.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/cls_u32.c b/net/sched/cls_u32.c
index 246f906..05d1780 100644
--- a/net/sched/cls_u32.c
+++ b/net/sched/cls_u32.c
@@ -387,7 +387,7 @@
static void u32_destroy(struct tcf_proto *tp)
{
struct tc_u_common *tp_c = tp->data;
- struct tc_u_hnode *root_ht = xchg(&tp->root, NULL);
+ struct tc_u_hnode *root_ht = tp->root;
WARN_ON(root_ht == NULL);
@@ -479,7 +479,7 @@
err = -EINVAL;
if (tb[TCA_U32_LINK]) {
u32 handle = nla_get_u32(tb[TCA_U32_LINK]);
- struct tc_u_hnode *ht_down = NULL;
+ struct tc_u_hnode *ht_down = NULL, *ht_old;
if (TC_U32_KEY(handle))
goto errout;
@@ -493,11 +493,12 @@
}
tcf_tree_lock(tp);
- ht_down = xchg(&n->ht_down, ht_down);
+ ht_old = n->ht_down;
+ n->ht_down = ht_down;
tcf_tree_unlock(tp);
- if (ht_down)
- ht_down->refcnt--;
+ if (ht_old)
+ ht_old->refcnt--;
}
if (tb[TCA_U32_CLASSID]) {
n->res.classid = nla_get_u32(tb[TCA_U32_CLASSID]);
