Re: [PATCH v3 1/3] hw/virtio: Comment virtqueue_flush() must be called with RCU read lock

[Stefan Hajnoczi]

On Mon, Sep 27, 2021 at 01:29:46PM +0200, Cornelia Huck wrote:
> On Mon, Sep 27 2021, Philippe Mathieu-Daudé <philmd@redhat.com> wrote:
> 
> > On 9/27/21 12:18, Cornelia Huck wrote:
> >> On Mon, Sep 06 2021, Philippe Mathieu-Daudé <philmd@redhat.com> wrote:
> >> 
> >>> Reported-by: Stefano Garzarella <sgarzare@redhat.com>
> >>> Suggested-by: Stefan Hajnoczi <stefanha@redhat.com>
> >>> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> >>> ---
> >>>  include/hw/virtio/virtio.h | 7 +++++++
> >>>  hw/virtio/virtio.c         | 1 +
> >>>  2 files changed, 8 insertions(+)
> >>>
> >>> diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
> >>> index 8bab9cfb750..c1c5f6e53c8 100644
> >>> --- a/include/hw/virtio/virtio.h
> >>> +++ b/include/hw/virtio/virtio.h
> >>> @@ -186,6 +186,13 @@ void virtio_delete_queue(VirtQueue *vq);
> >>>  
> >>>  void virtqueue_push(VirtQueue *vq, const VirtQueueElement *elem,
> >>>                      unsigned int len);
> >>> +/**
> >>> + * virtqueue_flush:
> >>> + * @vq: The #VirtQueue
> >>> + * @count: Number of elements to flush
> >>> + *
> >>> + * Must be called within RCU critical section.
> >>> + */
> >> 
> >> Hm... do these doc comments belong into .h files, or rather into .c files?
> >
> > Maybe we should restart this old thread, vote(?) and settle on a style?
> >
> > https://lore.kernel.org/qemu-devel/349cd87b-0526-30b8-d9cd-0eee537ab5a4@redhat.com/
> 
> My vote would still go to putting this into .c files :) Not sure if we
> want to go through the hassle of a wholesale cleanup; but if others
> agree, we could at least start with putting new doc comments next to the
> implementation.

In the virtio.c/h case doc comments (and especially the RCU-related
ones) are in the .c file. The exception is that constants and structs
are documented in the header file.

I would follow that and avoid duplicating doc comments into the .h file.

Stefan

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