Re: [RFC PATCH 16/27] virtio: Expose virtqueue_alloc_element

[Eugenio Perez Martin]

On Tue, Dec 8, 2020 at 9:26 AM Stefan Hajnoczi <stefanha@gmail.com> wrote:
>
> On Fri, Nov 20, 2020 at 07:50:54PM +0100, Eugenio Pérez wrote:
> > Specify VirtQueueElement * as return type makes no harm at this moment.
>
> The reason for the void * return type is that C implicitly converts void
> pointers to pointers of any type. The function takes a size_t sz
> argument so it can allocate a object of user-defined size. The idea is
> that the user's struct embeds a VirtQueueElement field. Changing the
> return type to VirtQueueElement * means that callers may need to
> explicitly cast to the user's struct type.
>
> It's a question of coding style but I think the void * return type
> communicates what is going on better than VirtQueueElement *.

Right, what I meant with that is that nobody uses that feature, but I
just re-check and I saw that contrib/vhost-user-blk actually uses it
(not checked for more uses). I think it is better just to drop this
commit.

Thanks!