Re: [PATCH v2] kcov, usbip: collect coverage from vhci_rx_loop

[Shuah Khan]

On 10/16/20 8:18 AM, Andrey Konovalov wrote:
> On Tue, Oct 13, 2020 at 7:28 PM Shuah Khan <skhan@xxxxxxxxxxxxxxxxxxx> wrote:
> > On 10/12/20 11:10 AM, Andrey Konovalov wrote:
> > > From: Nazime Hande Harputluoglu <handeharputlu@xxxxxxxxxx>
> > >
> > > Add kcov_remote_start()/kcov_remote_stop() annotations to the
> > > vhci_rx_loop() function, which is responsible for parsing USB/IP packets
> > > coming into USB/IP client.
> > >
> > > Since vhci_rx_loop() threads are spawned per vhci_hcd device instance, the
> > > common kcov handle is used for kcov_remote_start()/stop() annotations
> > > (see Documentation/dev-tools/kcov.rst for details). As the result kcov
> > > can now be used to collect coverage from vhci_rx_loop() threads.
> > >
> > > Signed-off-by: Nazime Hande Harputluoglu <handeharputlu@xxxxxxxxxx>
> > > ---
> > >
> > > Changes v1->v2:
> > > - Fix spacing issues.
> > > - Add ifdef CONFIG_KCOV around kcov_handle in usbip_device struct.
> >
> > Does this compile without CONFIG_KCOV?
> >
> > > ---
> > >    drivers/usb/usbip/usbip_common.h |  4 ++++
> > >    drivers/usb/usbip/vhci_rx.c      |  3 +++
> > >    drivers/usb/usbip/vhci_sysfs.c   | 12 +++++++-----
> > >    3 files changed, 14 insertions(+), 5 deletions(-)
> > >
> > > diff --git a/drivers/usb/usbip/usbip_common.h b/drivers/usb/usbip/usbip_common.h
> > > index 8be857a4fa13..0906182011d6 100644
> > > --- a/drivers/usb/usbip/usbip_common.h
> > > +++ b/drivers/usb/usbip/usbip_common.h
> > > @@ -277,6 +277,10 @@ struct usbip_device {
> > >                void (*reset)(struct usbip_device *);
> > >                void (*unusable)(struct usbip_device *);
> > >        } eh_ops;
> > > +
> > > +#ifdef CONFIG_KCOV
> > > +     u64 kcov_handle;
> > > +#endif
>
> Hi Shuah,
>
> We could have this field always defined, which allows us to not check
> CONFIG_KCOV in the places where it's used (this is what we do for
> vhost; the kcov functions will be optimized away). Or we could keep
> the ifdef CONFIG_KCOV check here, and then add the same checks to
> other places.
>
> What would be your preference here?

Let's keep it in ifdef CONFIG_KCOV and add checks to keep this
limited to just the kcov case.

thanks,
-- Shuah