Re: [PATCH net-next v2] netlink: add tracepoint at NL_SET_ERR_MSG

[Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>]

On Wed, Feb 03, 2021 at 10:48:16PM -0300, Marcelo Ricardo Leitner wrote:
> From: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
> 
> Often userspace won't request the extack information, or they don't log it
> because of log level or so, and even when they do, sometimes it's not
> enough to know exactly what caused the error.
> 
> Netlink extack is the standard way of reporting erros with descriptive
> error messages. With a trace point on it, we then can know exactly where
> the error happened, regardless of userspace app. Also, we can even see if
> the err msg was overwritten.
> 
> The wrapper do_trace_netlink_extack() is because trace points shouldn't be
> called from .h files, as trace points are not that small, and the function
> call to do_trace_netlink_extack() on the macros is not protected by
> tracepoint_enabled() because the macros are called from modules, and this
> would require exporting some trace structs. As this is error path, it's
> better to export just the wrapper instead.
> 
> v2: removed leftover tracepoint declaration

Whoops, missed a blank line here.
Please just let me know if I should send a new one.
Thanks.

> Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>