pkt_sched: remove unnecessary xchg() in packet schedulers
The use of xchg() hasn't been necessary since 2.2.something when proper
locking was added to packet schedulers.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/sch_atm.c b/net/sched/sch_atm.c
index ca90f6e..2a8b83a 100644
--- a/net/sched/sch_atm.c
+++ b/net/sched/sch_atm.c
@@ -102,7 +102,8 @@
return -EINVAL;
if (!new)
new = &noop_qdisc;
- *old = xchg(&flow->q, new);
+ *old = flow->q;
+ flow->q = new;
if (*old)
qdisc_reset(*old);
return 0;
diff --git a/net/sched/sch_cbq.c b/net/sched/sch_cbq.c
index a99e37e..3a9569a 100644
--- a/net/sched/sch_cbq.c
+++ b/net/sched/sch_cbq.c
@@ -1635,7 +1635,8 @@
#endif
}
sch_tree_lock(sch);
- *old = xchg(&cl->q, new);
+ *old = cl->q;
+ cl->q = new;
qdisc_tree_decrease_qlen(*old, (*old)->q.qlen);
qdisc_reset(*old);
sch_tree_unlock(sch);
@@ -1776,8 +1777,8 @@
cbq_deactivate_class(cl);
if (rtab) {
- rtab = xchg(&cl->R_tab, rtab);
- qdisc_put_rtab(rtab);
+ qdisc_put_rtab(cl->R_tab);
+ cl->R_tab = rtab;
}
if (tb[TCA_CBQ_LSSOPT])
diff --git a/net/sched/sch_drr.c b/net/sched/sch_drr.c
index e71a5de..8d523d9 100644
--- a/net/sched/sch_drr.c
+++ b/net/sched/sch_drr.c
@@ -208,7 +208,8 @@
sch_tree_lock(sch);
drr_purge_queue(cl);
- *old = xchg(&cl->qdisc, new);
+ *old = cl->qdisc;
+ cl->qdisc = new;
sch_tree_unlock(sch);
return 0;
}
diff --git a/net/sched/sch_dsmark.c b/net/sched/sch_dsmark.c
index 3f9427a..d303daa 100644
--- a/net/sched/sch_dsmark.c
+++ b/net/sched/sch_dsmark.c
@@ -68,7 +68,8 @@
}
sch_tree_lock(sch);
- *old = xchg(&p->q, new);
+ *old = p->q;
+ p->q = new;
qdisc_tree_decrease_qlen(*old, (*old)->q.qlen);
qdisc_reset(*old);
sch_tree_unlock(sch);
diff --git a/net/sched/sch_hfsc.c b/net/sched/sch_hfsc.c
index 071c474..51dd3f4 100644
--- a/net/sched/sch_hfsc.c
+++ b/net/sched/sch_hfsc.c
@@ -1202,7 +1202,8 @@
sch_tree_lock(sch);
hfsc_purge_queue(sch, cl);
- *old = xchg(&cl->qdisc, new);
+ *old = cl->qdisc;
+ cl->qdisc = new;
sch_tree_unlock(sch);
return 0;
}
diff --git a/net/sched/sch_htb.c b/net/sched/sch_htb.c
index 83f5e69..3a119f5 100644
--- a/net/sched/sch_htb.c
+++ b/net/sched/sch_htb.c
@@ -1100,7 +1100,9 @@
== NULL)
return -ENOBUFS;
sch_tree_lock(sch);
- if ((*old = xchg(&cl->un.leaf.q, new)) != NULL) {
+ *old = cl->un.leaf.q;
+ cl->un.leaf.q = new;
+ if (*old != NULL) {
qdisc_tree_decrease_qlen(*old, (*old)->q.qlen);
qdisc_reset(*old);
}
diff --git a/net/sched/sch_multiq.c b/net/sched/sch_multiq.c
index f645ac5..7e15186 100644
--- a/net/sched/sch_multiq.c
+++ b/net/sched/sch_multiq.c
@@ -214,7 +214,8 @@
q->bands = qopt->bands;
for (i = q->bands; i < q->max_bands; i++) {
if (q->queues[i] != &noop_qdisc) {
- struct Qdisc *child = xchg(&q->queues[i], &noop_qdisc);
+ struct Qdisc *child = q->queues[i];
+ q->queues[i] = &noop_qdisc;
qdisc_tree_decrease_qlen(child, child->q.qlen);
qdisc_destroy(child);
}
@@ -224,7 +225,7 @@
for (i = 0; i < q->bands; i++) {
if (q->queues[i] == &noop_qdisc) {
- struct Qdisc *child;
+ struct Qdisc *child, *old;
child = qdisc_create_dflt(qdisc_dev(sch),
sch->dev_queue,
&pfifo_qdisc_ops,
@@ -232,12 +233,13 @@
i + 1));
if (child) {
sch_tree_lock(sch);
- child = xchg(&q->queues[i], child);
+ old = q->queues[i];
+ q->queues[i] = child;
- if (child != &noop_qdisc) {
- qdisc_tree_decrease_qlen(child,
- child->q.qlen);
- qdisc_destroy(child);
+ if (old != &noop_qdisc) {
+ qdisc_tree_decrease_qlen(old,
+ old->q.qlen);
+ qdisc_destroy(old);
}
sch_tree_unlock(sch);
}
diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c
index 3cbc3ff..f840d6b 100644
--- a/net/sched/sch_netem.c
+++ b/net/sched/sch_netem.c
@@ -331,10 +331,9 @@
root_lock = qdisc_root_sleeping_lock(sch);
spin_lock_bh(root_lock);
- d = xchg(&q->delay_dist, d);
+ kfree(q->delay_dist);
+ q->delay_dist = d;
spin_unlock_bh(root_lock);
-
- kfree(d);
return 0;
}
diff --git a/net/sched/sch_prio.c b/net/sched/sch_prio.c
index ea65a87..94cecef 100644
--- a/net/sched/sch_prio.c
+++ b/net/sched/sch_prio.c
@@ -187,7 +187,8 @@
memcpy(q->prio2band, qopt->priomap, TC_PRIO_MAX+1);
for (i=q->bands; i<TCQ_PRIO_BANDS; i++) {
- struct Qdisc *child = xchg(&q->queues[i], &noop_qdisc);
+ struct Qdisc *child = q->queues[i];
+ q->queues[i] = &noop_qdisc;
if (child != &noop_qdisc) {
qdisc_tree_decrease_qlen(child, child->q.qlen);
qdisc_destroy(child);
@@ -197,18 +198,19 @@
for (i=0; i<q->bands; i++) {
if (q->queues[i] == &noop_qdisc) {
- struct Qdisc *child;
+ struct Qdisc *child, *old;
child = qdisc_create_dflt(qdisc_dev(sch), sch->dev_queue,
&pfifo_qdisc_ops,
TC_H_MAKE(sch->handle, i + 1));
if (child) {
sch_tree_lock(sch);
- child = xchg(&q->queues[i], child);
+ old = q->queues[i];
+ q->queues[i] = child;
- if (child != &noop_qdisc) {
- qdisc_tree_decrease_qlen(child,
- child->q.qlen);
- qdisc_destroy(child);
+ if (old != &noop_qdisc) {
+ qdisc_tree_decrease_qlen(old,
+ old->q.qlen);
+ qdisc_destroy(old);
}
sch_tree_unlock(sch);
}
diff --git a/net/sched/sch_red.c b/net/sched/sch_red.c
index 6a0371c..2bdf241 100644
--- a/net/sched/sch_red.c
+++ b/net/sched/sch_red.c
@@ -202,7 +202,8 @@
q->limit = ctl->limit;
if (child) {
qdisc_tree_decrease_qlen(q->qdisc, q->qdisc->q.qlen);
- qdisc_destroy(xchg(&q->qdisc, child));
+ qdisc_destroy(q->qdisc);
+ q->qdisc = child;
}
red_set_parms(&q->parms, ctl->qth_min, ctl->qth_max, ctl->Wlog,
@@ -283,7 +284,8 @@
new = &noop_qdisc;
sch_tree_lock(sch);
- *old = xchg(&q->qdisc, new);
+ *old = q->qdisc;
+ q->qdisc = new;
qdisc_tree_decrease_qlen(*old, (*old)->q.qlen);
qdisc_reset(*old);
sch_tree_unlock(sch);
diff --git a/net/sched/sch_tbf.c b/net/sched/sch_tbf.c
index bb7783d..a2f93c0 100644
--- a/net/sched/sch_tbf.c
+++ b/net/sched/sch_tbf.c
@@ -236,6 +236,7 @@
struct tc_tbf_qopt *qopt;
struct qdisc_rate_table *rtab = NULL;
struct qdisc_rate_table *ptab = NULL;
+ struct qdisc_rate_table *tmp;
struct Qdisc *child = NULL;
int max_size,n;
@@ -284,7 +285,8 @@
sch_tree_lock(sch);
if (child) {
qdisc_tree_decrease_qlen(q->qdisc, q->qdisc->q.qlen);
- qdisc_destroy(xchg(&q->qdisc, child));
+ qdisc_destroy(q->qdisc);
+ q->qdisc = child;
}
q->limit = qopt->limit;
q->mtu = qopt->mtu;
@@ -292,8 +294,14 @@
q->buffer = qopt->buffer;
q->tokens = q->buffer;
q->ptokens = q->mtu;
- rtab = xchg(&q->R_tab, rtab);
- ptab = xchg(&q->P_tab, ptab);
+
+ tmp = q->R_tab;
+ q->R_tab = rtab;
+ rtab = tmp;
+
+ tmp = q->P_tab;
+ q->P_tab = ptab;
+ ptab = tmp;
sch_tree_unlock(sch);
err = 0;
done:
@@ -383,7 +391,8 @@
new = &noop_qdisc;
sch_tree_lock(sch);
- *old = xchg(&q->qdisc, new);
+ *old = q->qdisc;
+ q->qdisc = new;
qdisc_tree_decrease_qlen(*old, (*old)->q.qlen);
qdisc_reset(*old);
sch_tree_unlock(sch);