Re: [PATCH] net: drop_monitor: use IS_REACHABLE() to guard net_dm_hw_report()

[Neil Horman]

On Wed, Mar 11, 2020 at 11:31:43AM +0200, Ido Schimmel wrote:
> On Wed, Mar 11, 2020 at 03:29:25PM +0900, Masahiro Yamada wrote:
> > In net/Kconfig, NET_DEVLINK implies NET_DROP_MONITOR.
> > 
> > The original behavior of the 'imply' keyword prevents NET_DROP_MONITOR
> > from being 'm' when NET_DEVLINK=y.
> > 
> > With the planned Kconfig change that relaxes the 'imply', the
> > combination of NET_DEVLINK=y and NET_DROP_MONITOR=m would be allowed.
> > 
> > Use IS_REACHABLE() to avoid the vmlinux link error for this case.
> > 
> > Reported-by: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
> > Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>
> 
> Thanks, Masahiro.
> 
> Neil, Jiri, another option (long term) is to add a raw tracepoint (not
> part of ABI) in devlink and have drop monitor register its probe on it
> when monitoring.
> 
> Two advantages:
> 1. Consistent with what drop monitor is already doing with kfree_skb()
> tracepoint
> 2. We can remove 'imply NET_DROP_MONITOR' altogether
> 
> What do you think?
> 
Agreed, I think I like this implementation better.
Neil