netfilter: xt_quota: use per-rule spin lock

Use per-rule spin lock to improve the scalability.

Signed-off-by: Changli Gao <[e-mail]>
Signed-off-by: Patrick McHardy <[e-mail]>

net/netfilter/xt_quota.c

···
 #include <linux/netfilter/xt_quota.h>
 
 struct xt_quota_priv {
-	uint64_t quota;
+	spinlock_t	lock;
+	uint64_t	quota;
 };
 
 MODULE_LICENSE("GPL");
···
 MODULE_ALIAS("ipt_quota");
 MODULE_ALIAS("ip6t_quota");
 
-static DEFINE_SPINLOCK(quota_lock);
-
 static bool
 quota_mt(const struct sk_buff *skb, struct xt_action_param *par)
 {
···
 	struct xt_quota_priv *priv = q->master;
 	bool ret = q->flags & XT_QUOTA_INVERT;
 
-	spin_lock_bh(&quota_lock);
+	spin_lock_bh(&priv->lock);
 	if (priv->quota >= skb->len) {
 		priv->quota -= skb->len;
 		ret = !ret;
···
 	}
 	/* Copy quota back to matchinfo so that iptables can display it */
 	q->quota = priv->quota;
-	spin_unlock_bh(&quota_lock);
+	spin_unlock_bh(&priv->lock);
 
 	return ret;
 }
···
 	if (q->master == NULL)
 		return -ENOMEM;
 
+	spin_lock_init(&q->master->lock);
 	q->master->quota = q->quota;
 	return 0;
 }