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

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>

diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
index 177f240d59d40e4c9d98718086feccec50472724..c99ffe9cc88f87f93b71577f6adc3ee961645a3b 100644 (file)
--- a/include/net/sch_generic.h
+++ b/include/net/sch_generic.h
@@ -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;
        }

diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index 9984ccc459467f5b9b53bc70c22f069e46b9ef6b..d9ac60ffe927c6a0ebced39a5375e8c4444ea3ca 100644 (file)
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -725,8 +725,6 @@ static struct sk_buff *pfifo_fast_dequeue(struct Qdisc *qdisc)
                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);