net: add skb_queue_purge_reason and __skb_queue_purge_reason

skb_queue_purge() and __skb_queue_purge() become wrappers
around the new generic functions.

New SKB_DROP_REASON_QUEUE_PURGE drop reason is added,
but users can start adding more specific reasons.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/skbuff.h

@@ -3149,20 +3149,35 @@ static inline int skb_orphan_frags_rx(struct sk_buff *skb, gfp_t gfp_mask)
 }
 
 /**
- *	__skb_queue_purge - empty a list
+ *	__skb_queue_purge_reason - empty a list
  *	@list: list to empty
+ *	@reason: drop reason
  *
  *	Delete all buffers on an &sk_buff list. Each buffer is removed from
  *	the list and one reference dropped. This function does not take the
  *	list lock and the caller must hold the relevant locks to use it.
  */
-static inline void __skb_queue_purge(struct sk_buff_head *list)
+static inline void __skb_queue_purge_reason(struct sk_buff_head *list,
+					    enum skb_drop_reason reason)
 {
 	struct sk_buff *skb;
+
 	while ((skb = __skb_dequeue(list)) != NULL)
-		kfree_skb(skb);
+		kfree_skb_reason(skb, reason);
+}
+
+static inline void __skb_queue_purge(struct sk_buff_head *list)
+{
+	__skb_queue_purge_reason(list, SKB_DROP_REASON_QUEUE_PURGE);
+}
+
+void skb_queue_purge_reason(struct sk_buff_head *list,
+			    enum skb_drop_reason reason);
+
+static inline void skb_queue_purge(struct sk_buff_head *list)
+{
+	skb_queue_purge_reason(list, SKB_DROP_REASON_QUEUE_PURGE);
 }
-void skb_queue_purge(struct sk_buff_head *list);
 
 unsigned int skb_rbtree_purge(struct rb_root *root);
 

include/net/dropreason-core.h

@@ -79,6 +79,7 @@
 	FN(IPV6_NDISC_BAD_CODE)		\
 	FN(IPV6_NDISC_BAD_OPTIONS)	\
 	FN(IPV6_NDISC_NS_OTHERHOST)	\
+	FN(QUEUE_PURGE)			\
 	FNe(MAX)
 
 /**
@@ -342,6 +343,8 @@ enum skb_drop_reason {
 	 * for another host.
 	 */
 	SKB_DROP_REASON_IPV6_NDISC_NS_OTHERHOST,
+	/** @SKB_DROP_REASON_QUEUE_PURGE: bulk free. */
+	SKB_DROP_REASON_QUEUE_PURGE,
 	/**
 	 * @SKB_DROP_REASON_MAX: the maximum of core drop reasons, which
 	 * shouldn't be used as a real 'reason' - only for tracing code gen

net/core/skbuff.c

@@ -3701,20 +3701,23 @@ struct sk_buff *skb_dequeue_tail(struct sk_buff_head *list)
 EXPORT_SYMBOL(skb_dequeue_tail);
 
 /**
- *	skb_queue_purge - empty a list
+ *	skb_queue_purge_reason - empty a list
  *	@list: list to empty
+ *	@reason: drop reason
  *
  *	Delete all buffers on an &sk_buff list. Each buffer is removed from
  *	the list and one reference dropped. This function takes the list
  *	lock and is atomic with respect to other list locking functions.
  */
-void skb_queue_purge(struct sk_buff_head *list)
+void skb_queue_purge_reason(struct sk_buff_head *list,
+			    enum skb_drop_reason reason)
 {
 	struct sk_buff *skb;
+
 	while ((skb = skb_dequeue(list)) != NULL)
-		kfree_skb(skb);
+		kfree_skb_reason(skb, reason);
 }
-EXPORT_SYMBOL(skb_queue_purge);
+EXPORT_SYMBOL(skb_queue_purge_reason);
 
 /**
  *	skb_rbtree_purge - empty a skb rbtree