[PATCH v2 1/4] Defer skb allocation -- add destroy buffers function for virtio

[Shirley Ma <mashirle@xxxxxxxxxx>]

Signed-off-by: <xma@xxxxxxxxxx>
-------------

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index c708ecc..bb5eb7b 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -107,6 +107,16 @@ static struct page *get_a_page(struct virtnet_info *vi, gfp_t gfp_mask)
 	return p;
 }
 
+static void virtio_net_free_pages(void *buf)
+{
+	struct page *page, *next;
+
+	for (page = buf; page; page = next) {
+		next = (struct page *)page->private;
+		__free_pages(page, 0);
+	}
+}
+
 static void skb_xmit_done(struct virtqueue *svq)
 {
 	struct virtnet_info *vi = svq->vdev->priv;
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index fbd2ecd..db83465 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -334,6 +334,29 @@ static bool vring_enable_cb(struct virtqueue *_vq)
 	return true;
 }
 
+static int vring_destroy_bufs(struct virtqueue *_vq, void (*destroy)(void *))
+{
+	struct vring_virtqueue *vq = to_vvq(_vq);
+	void *buf;
+	unsigned int i;
+	int freed = 0;
+
+	START_USE(vq);
+
+	for (i = 0; i < vq->vring.num; i++) {
+		if (vq->data[i]) {
+			/* detach_buf clears data, so grab it now. */
+			buf = vq->data[i];
+			detach_buf(vq, i);
+			destroy(buf);
+			freed++;
+		}
+	}
+
+	END_USE(vq);
+	return freed;
+}
+
 irqreturn_t vring_interrupt(int irq, void *_vq)
 {
 	struct vring_virtqueue *vq = to_vvq(_vq);
@@ -360,6 +383,7 @@ static struct virtqueue_ops vring_vq_ops = {
 	.kick = vring_kick,
 	.disable_cb = vring_disable_cb,
 	.enable_cb = vring_enable_cb,
+	.destroy_bufs = vring_destroy_bufs,
 };
 
 struct virtqueue *vring_new_virtqueue(unsigned int num,
diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index 057a2e0..e6d7d77 100644
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h
@@ -71,6 +71,7 @@ struct virtqueue_ops {
 
 	void (*disable_cb)(struct virtqueue *vq);
 	bool (*enable_cb)(struct virtqueue *vq);
+	int (*destroy_bufs)(struct virtqueue *vq, void (*destory)(void *));
 };
 
 /**


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