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net: sched: remove qdisc->empty for lockless qdisc

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As MISSED and DRAINING state are used to indicate a non-empty
qdisc, qdisc->empty is not longer needed, so remove it.

Acked-by: Jakub Kicinski <kuba@kernel.org>
Tested-by: Vladimir Oltean <vladimir.oltean@nxp.com> # flexcan
Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Yunsheng Lin 2021-06-22 14:49:57 +08:00 committed by David S. Miller
parent c4fef01ba4
commit d3e0f57501
2 changed files with 3 additions and 13 deletions
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13
include/net/sch_generic.h
View File

@ -117,8 +117,6 @@ struct Qdisc {
spinlock_t busylock ____cacheline_aligned_in_smp;
spinlock_t seqlock;
/* for NOLOCK qdisc, true if there are no enqueued skbs */
bool empty;
struct rcu_head rcu;
/* private data */
@ -165,7 +163,7 @@ static inline bool qdisc_is_percpu_stats(const struct Qdisc *q)
static inline bool qdisc_is_empty(const struct Qdisc *qdisc)
{
if (qdisc_is_percpu_stats(qdisc))
return READ_ONCE(qdisc->empty);
return nolock_qdisc_is_empty(qdisc);
return !READ_ONCE(qdisc->q.qlen);
}
@ -173,7 +171,7 @@ static inline bool qdisc_run_begin(struct Qdisc *qdisc)
{
if (qdisc->flags & TCQ_F_NOLOCK) {
if (spin_trylock(&qdisc->seqlock))
goto nolock_empty;
return true;
/* If the MISSED flag is set, it means other thread has
* set the MISSED flag before second spin_trylock(), so
@ -195,12 +193,7 @@ static inline bool qdisc_run_begin(struct Qdisc *qdisc)
/* Retry again in case other CPU may not see the new flag
* after it releases the lock at the end of qdisc_run_end().
*/
if (!spin_trylock(&qdisc->seqlock))
return false;
nolock_empty:
WRITE_ONCE(qdisc->empty, false);
return true;
return spin_trylock(&qdisc->seqlock);
} else if (qdisc_is_running(qdisc)) {
return false;
}

3
net/sched/sch_generic.c
View File

@ -725,8 +725,6 @@ retry:
need_retry = false;
goto retry;
} else {
WRITE_ONCE(qdisc->empty, true);
}
return skb;
@ -927,7 +925,6 @@ struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
sch->enqueue = ops->enqueue;
sch->dequeue = ops->dequeue;
sch->dev_queue = dev_queue;
sch->empty = true;
dev_hold(dev);
refcount_set(&sch->refcnt, 1);