From c021eac4148c16bf53baa0dd14e8ebee6f39dab5 Mon Sep 17 00:00:00 2001 From: Shirley Ma Date: Mon, 18 Jan 2010 19:15:23 +0530 Subject: virtio: Add ability to detach unused buffers from vrings There's currently no way for a virtio driver to ask for unused buffers, so it has to keep a list itself to reclaim them at shutdown. This is redundant, since virtio_ring stores that information. So add a new hook to do this. Signed-off-by: Shirley Ma Signed-off-by: Amit Shah Signed-off-by: Rusty Russell --- drivers/virtio/virtio_ring.c | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) (limited to 'drivers/virtio/virtio_ring.c') diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index 827f7e04261..782b7292a3d 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -351,6 +351,30 @@ static bool vring_enable_cb(struct virtqueue *_vq) return true; } +static void *vring_detach_unused_buf(struct virtqueue *_vq) +{ + struct vring_virtqueue *vq = to_vvq(_vq); + unsigned int i; + void *buf; + + START_USE(vq); + + for (i = 0; i < vq->vring.num; i++) { + if (!vq->data[i]) + continue; + /* detach_buf clears data, so grab it now. */ + buf = vq->data[i]; + detach_buf(vq, i); + END_USE(vq); + return buf; + } + /* That should have freed everything. */ + BUG_ON(vq->num_free != vq->vring.num); + + END_USE(vq); + return NULL; +} + irqreturn_t vring_interrupt(int irq, void *_vq) { struct vring_virtqueue *vq = to_vvq(_vq); @@ -377,6 +401,7 @@ static struct virtqueue_ops vring_vq_ops = { .kick = vring_kick, .disable_cb = vring_disable_cb, .enable_cb = vring_enable_cb, + .detach_unused_buf = vring_detach_unused_buf, }; struct virtqueue *vring_new_virtqueue(unsigned int num, -- cgit v1.2.3-70-g09d2