Re: [PATCH RFC 3/3] vhost, kcov: collect coverage from vhost_worker

[Greg Kroah-Hartman]

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
>  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 
> > > ---
> > >  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
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Re: [PATCH RFC 3/3] vhost, kcov: collect coverage from vhost_worker

[Greg Kroah-Hartman]

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 
> ---
>  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.

>   work->fn(work);
> +#ifdef CONFIG_KCOV
> + kcov_remote_stop();
> +#endif
>   if (need_resched())
>   schedule();
>   }
> @@ -546,6 +552,9 @@ long vhost_dev_set_owner(struct vhost_dev *dev)
>  
>   /* No owner, become one */
>   dev->mm = get_task_mm(current);
> +#ifdef CONFIG_KCOV
> + dev->kcov_handle = current->kcov_handle;
> +#endif
>   worker = kthread_create(vhost_worker, dev, "vhost-%d", current->pid);
>   if (IS_ERR(worker)) {
>   err = PTR_ERR(worker);
> @@ -571,6 +580,9 @@ long vhost_dev_set_owner(struct vhost_dev *dev)
>   if (dev->mm)
>   mmput(dev->mm);
>   dev->mm = NULL;
> +#ifdef CONFIG_KCOV
> + dev->kcov_handle = 0;
> +#endif
>  err_mm:
>   return err;
>  }
> @@ -682,6 +694,9 @@ void vhost_dev_cleanup(struct vhost_dev *dev)
>   if (dev->worker) {
>   kthread_stop(dev->worker);
>   dev->worker = NULL;
> +#ifdef CONFIG_KCOV
> + dev->kcov_handle = 0;
> +#endif
>   }
>   if (dev->mm)
>   mmput(dev->mm);
> diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
> index e9ed2722b633..010ca1ebcbd5 100644
> --- a/drivers/vhost/vhost.h
> +++ b/drivers/vhost/vhost.h
> @@ -173,6 +173,9 @@ struct vhost_dev {
>   int iov_limit;
>   int weight;
>   int byte_weight;
> +#ifdef CONFIG_KCOV
> + u64 kcov_handle;
> +#endif

Why is this a #ifdef at all here?

thanks,

greg k-h
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