[PATCH net,stable v3] vhost: fix a few skb leaks

[wexu]

From: Wei Xu <wexu@xxxxxxxxxx>

Matthew found a roughly 40% tcp throughput regression with commit
c67df11f(vhost_net: try batch dequing from skb array) as discussed
in the following thread:
https://www.mail-archive.com/netdev@xxxxxxxxxxxxxxx/msg187936.html

This is v3.

v3:
- move freeing skb from vhost to tun/tap recvmsg() to not
  confuse the callers.

v2:
- add Matthew as the reporter, thanks matthew.
- moving zero headcount check ahead instead of defer consuming skb
  due to jason and mst's comment.
- add freeing skb in favor of recvmsg() fails.

Wei Xu (3):
  vhost: fix skb leak in handle_rx()
  tun: free skb in early errors
  tap: free skb if flags error

 drivers/net/tap.c   |  6 +++++-
 drivers/net/tun.c   | 14 +++++++++++---
 drivers/vhost/net.c | 20 ++++++++++----------
 3 files changed, 26 insertions(+), 14 deletions(-)

-- 
1.8.3.1