static void *vring_get_buf(struct virtqueue *_vq, unsigned int *len)
{
struct vring_virtqueue *vq = to_vvq(_vq);
void *ret;
struct vring_used_elem *u;
unsigned int i;
if (!more_used(vq)) {
DPrintf(4, ("No more buffers in queue: last_used_idx %d vring.used->idx %d\n",
vq->last_used_idx,
vq->vring.used->idx));
return NULL;
}
/* Only get used array entries after they have been exposed by host. */
rmb();
u = &vq->vring.used->ring[vq->last_used_idx % vq->vring.num];
i = u->id;
*len = u->len;
DPrintf(4, ("%s>>> id %d, len %d\n", __FUNCTION__, i, *len) );
if (i >= vq->vring.num) {
DPrintf(0, ("id %u out of range\n", i) );
return NULL;
}
if (!vq->data[i]) {
DPrintf(0, ("id %u is not a head!\n", i) );
return NULL;
}
/* detach_buf clears data, so grab it now. */
ret = vq->data[i];
detach_buf(vq, i);
++vq->last_used_idx;
if (!(vq->vring.avail->flags & VRING_AVAIL_F_NO_INTERRUPT)) {
*vq->vring.vring_last_used_ptr = vq->last_used_idx;
mb();
}
return ret;
}
static bool vring_enable_cb(struct virtqueue *_vq)
{
struct vring_virtqueue *vq = to_vvq(_vq);
START_USE(vq);
/* We optimistically turn back on interrupts, then check if there was
* more to do. */
vq->vring.avail->flags &= ~VRING_AVAIL_F_NO_INTERRUPT;
mb();
if (unlikely(more_used(vq))) {
END_USE(vq);
return false;
}
END_USE(vq);
return true;
}
irqreturn_t vring_interrupt(int irq, void *_vq)
{
struct vring_virtqueue *vq = to_vvq(_vq);
if (!more_used(vq)) {
pr_debug("virtqueue interrupt with no work for %p\n", vq);
return IRQ_NONE;
}
if (unlikely(vq->broken))
return IRQ_HANDLED;
pr_debug("virtqueue callback for %p (%p)\n", vq, vq->vq.callback);
if (vq->vq.callback)
vq->vq.callback(&vq->vq);
return IRQ_HANDLED;
}
static bool vring_restart(struct virtqueue *_vq)
{
struct vring_virtqueue *vq = to_vvq(_vq);
DPrintf(6, ("%s\n", __FUNCTION__) );
//BUG_ON(!(vq->vring.avail->flags & VRING_AVAIL_F_NO_INTERRUPT));
/* We optimistically turn back on interrupts, then check if there was
* more to do. */
vring_enable_interrupts(_vq);
if (more_used(vq)) {
vring_disable_interrupts(_vq);
return 0;
}
return 1;
}
void *virtqueue_get_buf(struct virtqueue *_vq, unsigned int *len)
{
struct vring_virtqueue *vq = to_vvq(_vq);
void *ret;
unsigned int i;
START_USE(vq);
if (unlikely(vq->broken)) {
END_USE(vq);
return NULL;
}
if (!more_used(vq)) {
pr_debug("No more buffers in queue\n");
END_USE(vq);
return NULL;
}
/* Only get used array entries after they have been exposed by host. */
virtio_rmb();
i = vq->vring.used->ring[vq->last_used_idx%vq->vring.num].id;
*len = vq->vring.used->ring[vq->last_used_idx%vq->vring.num].len;
if (unlikely(i >= vq->vring.num)) {
BAD_RING(vq, "id %u out of range\n", i);
return NULL;
}
if (unlikely(!vq->data[i])) {
BAD_RING(vq, "id %u is not a head!\n", i);
return NULL;
}
/* detach_buf clears data, so grab it now. */
ret = vq->data[i];
detach_buf(vq, i);
vq->last_used_idx++;
END_USE(vq);
return ret;
}