On Tue, May 25, 2021 at 10:23:39AM +0800, Jason Wang wrote: > > 在 2021/5/20 下午10:13, Stefan Hajnoczi 写道: > > Add an API to check whether there are pending used buffers. There is > > already a similar API called virtqueue_poll() but it only works together > > with virtqueue_enable_cb_prepare(). The patches that follow add blk-mq > > ->poll() support to virtio_blk and they need to check for used buffers > > without re-enabling virtqueue callbacks, so introduce an API for it. > > > > Signed-off-by: Stefan Hajnoczi <[email protected]> > > > Typo in the subject.
Thanks, will fix.
> > +/**
> > + * virtqueue_more_used - check if there are used buffers pending
> > + * @_vq: the struct virtqueue we're talking about.
> > + *
> > + * Returns true if there are used buffers, false otherwise. May be called
> > at
> > + * the same time as other virtqueue operations, but actually calling
> > + * virtqueue_get_buf() requires serialization so be mindful of the race
> > between
> > + * calling virtqueue_more_used() and virtqueue_get_buf().
> > + */
> > +bool virtqueue_more_used(const struct virtqueue *_vq)
> > +{
> > + struct vring_virtqueue *vq = to_vvq(_vq);
> > +
> > + return more_used(vq);
> > +}
> > +EXPORT_SYMBOL_GPL(virtqueue_more_used);
>
>
> It's worth to mention that the function is not serialized (no barriers).
Thanks, will fix.
Stefan
signature.asc
Description: PGP signature
_______________________________________________ Virtualization mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/virtualization
