| Message ID | 20200311062925.5163-1-masahiroy@kernel.org |
|---|---|
| State | Not Applicable |
| Delegated to: | David Miller |
| Headers | show |
| Series | net: drop_monitor: use IS_REACHABLE() to guard net_dm_hw_report() | expand |
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@canb.auug.org.au> > Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> 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?
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@canb.auug.org.au> > > Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> > > 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
On Wed, Mar 11, 2020 at 06:47:56AM -0400, Neil Horman wrote: > 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@canb.auug.org.au> > > > Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> > > > > 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. OK, but I don't want to block Masahiro. I think we can go with his patch and then I'll add the raw tracepoint in the next release.
On Wed, Mar 11, 2020 at 01:28:33PM +0200, Ido Schimmel wrote: > On Wed, Mar 11, 2020 at 06:47:56AM -0400, Neil Horman wrote: > > 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@canb.auug.org.au> > > > > Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> > > > > > > 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. > > OK, but I don't want to block Masahiro. I think we can go with his patch > and then I'll add the raw tracepoint in the next release. > Yeah, ok, I can agree with that Acked-by: Neil Horman <nhorman@tuxdriver.com>
On Thu, Mar 12, 2020 at 2:31 AM Neil Horman <nhorman@tuxdriver.com> wrote: > > On Wed, Mar 11, 2020 at 01:28:33PM +0200, Ido Schimmel wrote: > > On Wed, Mar 11, 2020 at 06:47:56AM -0400, Neil Horman wrote: > > > 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@canb.auug.org.au> > > > > > Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> > > > > > > > > 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. > > > > OK, but I don't want to block Masahiro. I think we can go with his patch > > and then I'll add the raw tracepoint in the next release. > > > Yeah, ok, I can agree with that > Acked-by: Neil Horman <nhorman@tuxdriver.com> Thanks, I will insert this patch before the kconfig change with your Ack.
diff --git a/include/net/drop_monitor.h b/include/net/drop_monitor.h index 2ab668461463..f68bc373544a 100644 --- a/include/net/drop_monitor.h +++ b/include/net/drop_monitor.h @@ -19,7 +19,7 @@ struct net_dm_hw_metadata { struct net_device *input_dev; }; -#if IS_ENABLED(CONFIG_NET_DROP_MONITOR) +#if IS_REACHABLE(CONFIG_NET_DROP_MONITOR) void net_dm_hw_report(struct sk_buff *skb, const struct net_dm_hw_metadata *hw_metadata); #else
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@canb.auug.org.au> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> --- This build error was reported in linux-next. https://lkml.org/lkml/2020/3/10/1936 If this patch is acceptable, I'd like to get Ack from the maintainers, and insert this patch before my Kconfig change. include/net/drop_monitor.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)