Comment 10 for bug 1683305

Reviewed: https://review.opencontrail.org/31125
Committed: http://github.com/Juniper/contrail-vrouter/commit/fcf28b4ec975c4de18afc0b859c4ace5684d0eef
Submitter: Zuul (<email address hidden>)
Branch: R2.21.x

commit fcf28b4ec975c4de18afc0b859c4ace5684d0eef
Author: Anand H. Krishnan <email address hidden>
Date: Mon May 8 15:08:00 2017 +0530

A cloned skbuff should not be sent to napi_gro_receive

When skb_gro_receive merges skbs/fragments, it does not take
a reference to the underlying page, thus transferring the
original reference it had to the first packet of the packet
bundle. This will work fine for non-cloned packets.

However, for cloned packets, when the gro-ed packet is
eventually freed (because the original skb was not cloned and
hence reference was 1), the merged skb's frags also get freed
(put_page-ed) without taking into account the other references
that were held for the fragments (dataref). This will result in
bad page problems.

Hence, avoid GRO for cloned packets.

Change-Id: I867dc6eac82e1ebc7a0f496b928d66ff62409542
Closes-Bug: #1683305