[PATCH 4.9 63/71] net: modify skb_rbtree_purge to return the truesize of all purged skbs.

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Peter Oskolkov <posk@xxxxxxxxxx>

Tested: see the next patch is the series.

Suggested-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Signed-off-by: Peter Oskolkov <posk@xxxxxxxxxx>
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Cc: Florian Westphal <fw@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
(cherry picked from commit 385114dec8a49b5e5945e77ba7de6356106713f4)
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 include/linux/skbuff.h |    2 +-
 net/core/skbuff.c      |    6 +++++-
 2 files changed, 6 insertions(+), 2 deletions(-)

--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -2418,7 +2418,7 @@ static inline void __skb_queue_purge(str
 		kfree_skb(skb);
 }
 
-void skb_rbtree_purge(struct rb_root *root);
+unsigned int skb_rbtree_purge(struct rb_root *root);
 
 void *netdev_alloc_frag(unsigned int fragsz);
 
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -2425,23 +2425,27 @@ EXPORT_SYMBOL(skb_queue_purge);
 /**
  *	skb_rbtree_purge - empty a skb rbtree
  *	@root: root of the rbtree to empty
+ *	Return value: the sum of truesizes of all purged skbs.
  *
  *	Delete all buffers on an &sk_buff rbtree. Each buffer is removed from
  *	the list and one reference dropped. This function does not take
  *	any lock. Synchronization should be handled by the caller (e.g., TCP
  *	out-of-order queue is protected by the socket lock).
  */
-void skb_rbtree_purge(struct rb_root *root)
+unsigned int skb_rbtree_purge(struct rb_root *root)
 {
 	struct rb_node *p = rb_first(root);
+	unsigned int sum = 0;
 
 	while (p) {
 		struct sk_buff *skb = rb_entry(p, struct sk_buff, rbnode);
 
 		p = rb_next(p);
 		rb_erase(&skb->rbnode, root);
+		sum += skb->truesize;
 		kfree_skb(skb);
 	}
+	return sum;
 }
 
 /**