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>

1 files changed, 13 insertions, 4 deletions

diff --git a/net/sched/sch_tbf.c b/net/sched/sch_tbf.c
index bb7783d584bb..a2f93c09f3cc 100644
--- a/net/sched/sch_tbf.c
+++ b/net/sched/sch_tbf.c
@@ -236,6 +236,7 @@ static int tbf_change(struct Qdisc* sch, struct nlattr *opt)
         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 @@ static int tbf_change(struct Qdisc* sch, struct nlattr *opt)
         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 @@ static int tbf_change(struct Qdisc* sch, struct nlattr *opt)
         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 @@ static int tbf_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
                 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);