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Commit 806a8376 authored by Gao Feng's avatar Gao Feng Committed by David S. Miller
Browse files

pkt_sched: Remove useless qdisc_stab_lock 



The qdisc_stab_lock is used in qdisc_get_stab and qdisc_put_stab.
These two functions are invoked in qdisc_create, qdisc_change, and
qdisc_destroy which run fully under RTNL.

So it already makes sure only one could access the qdisc_stab_list at
the same time. Then it is unnecessary to use qdisc_stab_lock now.

Signed-off-by: default avatarGao Feng <fgao@ikuai8.com>
Acked-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 88c4845d

net/sched/sch_api.c

+0 −12
Original line number Diff line number Diff line
@@ -440,7 +440,6 @@ void qdisc_put_rtab(struct qdisc_rate_table *tab) 
EXPORT_SYMBOL(qdisc_put_rtab);



static LIST_HEAD(qdisc_stab_list);

static DEFINE_SPINLOCK(qdisc_stab_lock);



static const struct nla_policy stab_policy[TCA_STAB_MAX + 1] = {

	[TCA_STAB_BASE]	= { .len = sizeof(struct tc_sizespec) },
@@ -474,20 +473,15 @@ static struct qdisc_size_table *qdisc_get_stab(struct nlattr *opt) 
	if (tsize != s->tsize || (!tab && tsize > 0))

		return ERR_PTR(-EINVAL);



	spin_lock(&qdisc_stab_lock);



	list_for_each_entry(stab, &qdisc_stab_list, list) {

		if (memcmp(&stab->szopts, s, sizeof(*s)))

			continue;

		if (tsize > 0 && memcmp(stab->data, tab, tsize * sizeof(u16)))

			continue;

		stab->refcnt++;

		spin_unlock(&qdisc_stab_lock);

		return stab;

	}



	spin_unlock(&qdisc_stab_lock);



	stab = kmalloc(sizeof(*stab) + tsize * sizeof(u16), GFP_KERNEL);

	if (!stab)

		return ERR_PTR(-ENOMEM);
@@ -497,9 +491,7 @@ static struct qdisc_size_table *qdisc_get_stab(struct nlattr *opt) 
	if (tsize > 0)

		memcpy(stab->data, tab, tsize * sizeof(u16));



	spin_lock(&qdisc_stab_lock);

	list_add_tail(&stab->list, &qdisc_stab_list);

	spin_unlock(&qdisc_stab_lock);



	return stab;

}
@@ -514,14 +506,10 @@ void qdisc_put_stab(struct qdisc_size_table *tab) 
	if (!tab)

		return;



	spin_lock(&qdisc_stab_lock);



	if (--tab->refcnt == 0) {

		list_del(&tab->list);

		call_rcu_bh(&tab->rcu, stab_kfree_rcu);

	}



	spin_unlock(&qdisc_stab_lock);

}

EXPORT_SYMBOL(qdisc_put_stab);