Sometimes, gcc will optimize the function by spliting it to two or
more functions. In this case, kfree_skb() is splited to
kfree_skb and kfree_skb.part.0. However, the
function/tracepoint trace_kfree_skb() in it needs the return address
of kfree_skb().
This split makes the call chains becomes:
kfree_skb() -> kfree_skb.part.0 -> trace_kfree_skb()
which makes the return address that passed to trace_kfree_skb() be
kfree_skb().
Therefore, introduce '__fix_address', which is the combination of
'__noclone' and 'noinline', and apply it to kfree_skb() to
prevent to from being splited or made inline.
(Is it better to simply apply '__noclone oninline' to kfree_skb?
I'm thinking maybe other functions have the same problems)
Meanwhile, wrap 'skb_unref()' with 'unlikely()', as the compiler thinks
it is likely return true and splits kfree_skb().
Signed-off-by: Menglong Dong <imagedong@tencent.com>
Menglong Dong