[ Upstream commit 1394c1dec1c619a46867ed32791a29695372bff8 ] If we're fragmenting on local output, the original packet may contain ext data for the MCTP flows. We'll want this in the resulting fragment skbs too. So, do a skb_ext_copy() in the fragmentation path, and implement the MCTP-specific parts of an ext copy operation. Fixes: 67737c457281 ("mctp: Pass flow data & flow release events to drivers") Reported-by: Jian Zhang <zhangjian.3032@bytedance.com> Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au> Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>