On Thu, 25 Sep 2025 18:37:01 +0800 Jason Wang <[email protected]> wrote:
> Use u16 for last_used_idx in virtqueue_poll_split() to align with the > spec. If you care about performance you should pretty much never use 'u16' for function parameters, return values or any arithmetic. Just because the domain of the variable is [0..65535] doesn't mean that 'unsigned int' isn't the correct type. > > Acked-by: Eugenio Pérez <[email protected]> > Reviewed-by: Xuan Zhuo <[email protected]> > Signed-off-by: Jason Wang <[email protected]> > --- > drivers/virtio/virtio_ring.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c > index 58c03a8aab85..4679a027dc53 100644 > --- a/drivers/virtio/virtio_ring.c > +++ b/drivers/virtio/virtio_ring.c > @@ -806,7 +806,7 @@ static void detach_buf_split(struct vring_virtqueue *vq, > unsigned int head, > } > > static bool virtqueue_poll_split(const struct vring_virtqueue *vq, > - unsigned int last_used_idx) > + u16 last_used_idx) > { > return (u16)last_used_idx != virtio16_to_cpu(vq->vq.vdev, You can't want that (u16) cast now, I doubt it was ever needed. Note that the compiler promotes the value to 'signed int', so the LHS of the comparison is actually (int)(u16)last_used_idx. David > vq->split.vring.used->idx);
