[PATCH stable 4.4 03/11] net: modify skb_rbtree_purge to return the truesize of all purged skbs.

[Mao Wenan]

From: Peter Oskolkov <p...@google.com>

[ Upstream commit 385114dec8a49b5e5945e77ba7de6356106713f4 ]

Tested: see the next patch is the series.

Suggested-by: Eric Dumazet <eduma...@google.com>
Signed-off-by: Peter Oskolkov <p...@google.com>
Signed-off-by: Eric Dumazet <eduma...@google.com>
Cc: Florian Westphal <f...@strlen.de>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Mao Wenan <maowe...@huawei.com>
---
 include/linux/skbuff.h | 2 +-
 net/core/skbuff.c      | 6 +++++-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index a490dd7..8bfefdd 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -2273,7 +2273,7 @@ static inline void __skb_queue_purge(struct sk_buff_head 
*list)
                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);
 
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 8a57bba..49f73fb 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -2380,23 +2380,27 @@ 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;
 }
 
 /**
-- 
1.8.3.1