Linux Virtualization - Oct 2019 - [PATCH RFC 3/3] vhost, kcov: collect coverage from vhost_worker

On Thu, Oct 17, 2019 at 09:00:18PM +0200, Andrey Konovalov
wrote:
> On Thu, Oct 17, 2019 at 8:18 PM Greg Kroah-Hartman
> <gregkh at linuxfoundation.org> wrote:
> >
> > On Thu, Oct 17, 2019 at 07:44:15PM +0200, Andrey Konovalov wrote:
> > > This patch adds kcov_remote_start/kcov_remote_stop annotations to
the
> > > vhost_worker function, which is responsible for processing vhost
works.
> > > Since vhost_worker is spawned when a vhost device instance is
created,
> > > the common kcov handle is used for kcov_remote_start/stop
annotations.
> > >
> > > Signed-off-by: Andrey Konovalov <andreyknvl at google.com>
> > > ---
> > >  drivers/vhost/vhost.c | 15 +++++++++++++++
> > >  drivers/vhost/vhost.h |  3 +++
> > >  2 files changed, 18 insertions(+)
> > >
> > > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
> > > index 36ca2cf419bf..71a349f6b352 100644
> > > --- a/drivers/vhost/vhost.c
> > > +++ b/drivers/vhost/vhost.c
> > > @@ -357,7 +357,13 @@ static int vhost_worker(void *data)
> > >               llist_for_each_entry_safe(work, work_next, node,
node) {
> > >                       clear_bit(VHOST_WORK_QUEUED,
&work->flags);
> > >                       __set_current_state(TASK_RUNNING);
> > > +#ifdef CONFIG_KCOV
> > > +                     kcov_remote_start(dev->kcov_handle);
> > > +#endif
> >
> > Shouldn't you hide these #ifdefs in a .h file?  This is not a
"normal"
> > kernel coding style at all.
> 
> Well, if it's acceptable to add a kcov_handle field into vhost_dev
> even when CONFIG_KCOV is not enabled, then we can get rid of those
> #ifdefs.
It should be, it's not a big deal and there's not a ton of those
structures around that one more field is going to hurt anything...

thanks,

greg k-h