ipv6: mcast: Simplify mld_clear_{report|query}()

Use __skb_queue_purge() instead of re-implementing it. Note that it uses
kfree_skb_reason() instead of kfree_skb() internally, and pass
SKB_DROP_REASON_QUEUE_PURGE drop reason to the kfree_skb tracepoint.

Signed-off-by: Yue Haibing <[email protected]>
Reviewed-by: Hangbin Liu <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

Author: Yue Haibing

net/ipv6/mcast.c

@@ -845,21 +845,15 @@ static void mld_clear_delrec(struct inet6_dev *idev)
 
 static void mld_clear_query(struct inet6_dev *idev)
 {
-	struct sk_buff *skb;
-
 	spin_lock_bh(&idev->mc_query_lock);
-	while ((skb = __skb_dequeue(&idev->mc_query_queue)))
-		kfree_skb(skb);
+	__skb_queue_purge(&idev->mc_query_queue);
 	spin_unlock_bh(&idev->mc_query_lock);
 }
 
 static void mld_clear_report(struct inet6_dev *idev)
 {
-	struct sk_buff *skb;
-
 	spin_lock_bh(&idev->mc_report_lock);
-	while ((skb = __skb_dequeue(&idev->mc_report_queue)))
-		kfree_skb(skb);
+	__skb_queue_purge(&idev->mc_report_queue);
 	spin_unlock_bh(&idev->mc_report_lock);
 }