From b94c8afcba3ae6584653b98e315446ea83be6ea5 Mon Sep 17 00:00:00 2001 From: Patrick McHardy Date: Thu, 20 Nov 2008 04:11:36 -0800 Subject: 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 Signed-off-by: David S. Miller --- net/sched/sch_atm.c | 3 ++- net/sched/sch_cbq.c | 7 ++++--- net/sched/sch_drr.c | 3 ++- net/sched/sch_dsmark.c | 3 ++- net/sched/sch_hfsc.c | 3 ++- net/sched/sch_htb.c | 4 +++- net/sched/sch_multiq.c | 16 +++++++++------- net/sched/sch_netem.c | 5 ++--- net/sched/sch_prio.c | 16 +++++++++------- net/sched/sch_red.c | 6 ++++-- net/sched/sch_tbf.c | 17 +++++++++++++---- 11 files changed, 52 insertions(+), 31 deletions(-) (limited to 'net') diff --git a/net/sched/sch_atm.c b/net/sched/sch_atm.c index ca90f6e59aee..2a8b83af7c47 100644 --- a/net/sched/sch_atm.c +++ b/net/sched/sch_atm.c @@ -102,7 +102,8 @@ static int atm_tc_graft(struct Qdisc *sch, unsigned long arg, 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 a99e37e9e6f1..3a9569a3396c 100644 --- a/net/sched/sch_cbq.c +++ b/net/sched/sch_cbq.c @@ -1635,7 +1635,8 @@ static int cbq_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new, #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_change_class(struct Qdisc *sch, u32 classid, u32 parentid, struct nlattr **t 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 e71a5de23e23..8d523d9b636c 100644 --- a/net/sched/sch_drr.c +++ b/net/sched/sch_drr.c @@ -208,7 +208,8 @@ static int drr_graft_class(struct Qdisc *sch, unsigned long arg, 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 3f9427a4b757..d303daa45d49 100644 --- a/net/sched/sch_dsmark.c +++ b/net/sched/sch_dsmark.c @@ -68,7 +68,8 @@ static int dsmark_graft(struct Qdisc *sch, unsigned long arg, } 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 071c4749a12b..51dd3f401623 100644 --- a/net/sched/sch_hfsc.c +++ b/net/sched/sch_hfsc.c @@ -1202,7 +1202,8 @@ hfsc_graft_class(struct Qdisc *sch, unsigned long arg, struct Qdisc *new, 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 83f5e69243c1..3a119f576bb3 100644 --- a/net/sched/sch_htb.c +++ b/net/sched/sch_htb.c @@ -1100,7 +1100,9 @@ static int htb_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new, == 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 f645ac55a1a1..7e151861794b 100644 --- a/net/sched/sch_multiq.c +++ b/net/sched/sch_multiq.c @@ -214,7 +214,8 @@ static int multiq_tune(struct Qdisc *sch, struct nlattr *opt) 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 @@ static int multiq_tune(struct Qdisc *sch, struct nlattr *opt) 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 @@ static int multiq_tune(struct Qdisc *sch, struct nlattr *opt) 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 3cbc3ff7b5bc..f840d6b27c65 100644 --- a/net/sched/sch_netem.c +++ b/net/sched/sch_netem.c @@ -331,10 +331,9 @@ static int get_dist_table(struct Qdisc *sch, const struct nlattr *attr) 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 ea65a87ec22c..94cecef70145 100644 --- a/net/sched/sch_prio.c +++ b/net/sched/sch_prio.c @@ -187,7 +187,8 @@ static int prio_tune(struct Qdisc *sch, struct nlattr *opt) memcpy(q->prio2band, qopt->priomap, TC_PRIO_MAX+1); for (i=q->bands; iqueues[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 @@ static int prio_tune(struct Qdisc *sch, struct nlattr *opt) for (i=0; ibands; 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 6a0371c22643..2bdf241f6315 100644 --- a/net/sched/sch_red.c +++ b/net/sched/sch_red.c @@ -202,7 +202,8 @@ static int red_change(struct Qdisc *sch, struct nlattr *opt) 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 @@ static int red_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); 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); -- cgit v1.2.3-59-g8ed1b