virtio_ring: add a func argument 'recycle_done' to virtqueue_reset()

When virtqueue_reset() has actually recycled all unused buffers,
additional work may be required in some cases. Relying solely on its
return status is fragile, so introduce a new function argument
'recycle_done', which is invoked when it really occurs.

Signed-off-by: Koichiro Den <koichiro.den@canonical.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Author: lkpdn

drivers/net/virtio_net.c

@@ -5711,7 +5711,7 @@ static int virtnet_rq_bind_xsk_pool(struct virtnet_info *vi, struct receive_queu
 
 	virtnet_rx_pause(vi, rq);
 
-	err = virtqueue_reset(rq->vq, virtnet_rq_unmap_free_buf);
+	err = virtqueue_reset(rq->vq, virtnet_rq_unmap_free_buf, NULL);
 	if (err) {
 		netdev_err(vi->dev, "reset rx fail: rx queue index: %d err: %d\n", qindex, err);
 
@@ -5740,7 +5740,7 @@ static int virtnet_sq_bind_xsk_pool(struct virtnet_info *vi,
 
 	virtnet_tx_pause(vi, sq);
 
-	err = virtqueue_reset(sq->vq, virtnet_sq_free_unused_buf);
+	err = virtqueue_reset(sq->vq, virtnet_sq_free_unused_buf, NULL);
 	if (err) {
 		netdev_err(vi->dev, "reset tx fail: tx queue index: %d err: %d\n", qindex, err);
 		pool = NULL;

drivers/virtio/virtio_ring.c

@@ -2827,6 +2827,7 @@ EXPORT_SYMBOL_GPL(virtqueue_resize);
  * virtqueue_reset - detach and recycle all unused buffers
  * @_vq: the struct virtqueue we're talking about.
  * @recycle: callback to recycle unused buffers
+ * @recycle_done: callback to be invoked when recycle for all unused buffers done
  *
  * Caller must ensure we don't call this with other virtqueue operations
  * at the same time (except where noted).
@@ -2838,14 +2839,17 @@ EXPORT_SYMBOL_GPL(virtqueue_resize);
  * -EPERM: Operation not permitted
  */
 int virtqueue_reset(struct virtqueue *_vq,
-		    void (*recycle)(struct virtqueue *vq, void *buf))
+		    void (*recycle)(struct virtqueue *vq, void *buf),
+		    void (*recycle_done)(struct virtqueue *vq))
 {
 	struct vring_virtqueue *vq = to_vvq(_vq);
 	int err;
 
 	err = virtqueue_disable_and_recycle(_vq, recycle);
 	if (err)
 		return err;
+	if (recycle_done)
+		recycle_done(_vq);
 
 	if (vq->packed_ring)
 		virtqueue_reinit_packed(vq);

include/linux/virtio.h

@@ -112,7 +112,8 @@ int virtqueue_resize(struct virtqueue *vq, u32 num,
 		     void (*recycle)(struct virtqueue *vq, void *buf),
 		     void (*recycle_done)(struct virtqueue *vq));
 int virtqueue_reset(struct virtqueue *vq,
-		    void (*recycle)(struct virtqueue *vq, void *buf));
+		    void (*recycle)(struct virtqueue *vq, void *buf),
+		    void (*recycle_done)(struct virtqueue *vq));
 
 struct virtio_admin_cmd {
 	__le16 opcode;