Am Freitag, 30. Mai 2008 schrieb Rusty Russell:
> It turns out that life is simpler if the host similarly ignores
> callback suppression when the ring is completely empty: the network
> driver wants to free up old packets in a timely manner, and otherwise
> has to use a timer to poll.
>
> We have to remove the code which ignores interrupts when the driver
> has disabled them (again, it had no locking and hence was unreliable
> anyway).
>
> Signed-off-by: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
> ---
> drivers/virtio/virtio_ring.c | 7 -------
> include/linux/virtio_config.h | 4 ++++
> 2 files changed, 4 insertions(+), 7 deletions(-)
>
> diff -r 95a02f0e0e21 drivers/virtio/virtio_ring.c
> --- a/drivers/virtio/virtio_ring.c Tue May 27 12:45:17 2008 +1000
> +++ b/drivers/virtio/virtio_ring.c Tue May 27 15:53:41 2008 +1000
> @@ -253,13 +253,6 @@ irqreturn_t vring_interrupt(int irq, voi
> if (unlikely(vq->broken))
> return IRQ_HANDLED;
>
> - /* Other side may have missed us turning off the interrupt,
> - * but we should preserve disable semantic for virtio users. */
> - if (unlikely(vq->vring.avail->flags & VRING_AVAIL_F_NO_INTERRUPT)) {
> - pr_debug("virtqueue interrupt after disable for %p\n", vq);
> - return IRQ_HANDLED;
> - }
> -
> pr_debug("virtqueue callback for %p (%p)\n", vq, vq->vq.callback);
> if (vq->vq.callback)
> vq->vq.callback(&vq->vq);
that part makes sense.
> diff -r 95a02f0e0e21 include/linux/virtio_config.h
> --- a/include/linux/virtio_config.h Tue May 27 12:45:17 2008 +1000
> +++ b/include/linux/virtio_config.h Tue May 27 15:53:41 2008 +1000
> @@ -14,6 +14,10 @@
> #define VIRTIO_CONFIG_S_DRIVER_OK 4
> /* We've given up on this device. */
> #define VIRTIO_CONFIG_S_FAILED 0x80
> +
> +/* Do we get callbacks when the ring is completely used, even if we've
> + * suppressed them? */
> +#define VIRTIO_F_NOTIFY_ON_EMPTY 24
24?
Does that mean the first 24 bits are driver owned and 24-31 are for the
common virtio code?
Christian
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