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

commit 8d6712c upstream.

When virtqueue_resize() 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 the recycle really occurs.

Cc: <stable@vger.kernel.org> # v6.11+
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/net/virtio_net.c

@@ -3165,7 +3165,7 @@ static int virtnet_rx_resize(struct virtnet_info *vi,
 
 	virtnet_rx_pause(vi, rq);
 
-	err = virtqueue_resize(rq->vq, ring_num, virtnet_rq_unmap_free_buf);
+	err = virtqueue_resize(rq->vq, ring_num, virtnet_rq_unmap_free_buf, NULL);
 	if (err)
 		netdev_err(vi->dev, "resize rx fail: rx queue index: %d err: %d\n", qindex, err);
 
@@ -3228,7 +3228,7 @@ static int virtnet_tx_resize(struct virtnet_info *vi, struct send_queue *sq,
 
 	virtnet_tx_pause(vi, sq);
 
-	err = virtqueue_resize(sq->vq, ring_num, virtnet_sq_free_unused_buf);
+	err = virtqueue_resize(sq->vq, ring_num, virtnet_sq_free_unused_buf, NULL);
 	if (err)
 		netdev_err(vi->dev, "resize tx fail: tx queue index: %d err: %d\n", qindex, err);
 

drivers/virtio/virtio_ring.c

@@ -2716,6 +2716,7 @@ EXPORT_SYMBOL_GPL(vring_create_virtqueue_dma);
  * @_vq: the struct virtqueue we're talking about.
  * @num: new ring num
  * @recycle: callback to recycle unused buffers
+ * @recycle_done: callback to be invoked when recycle for all unused buffers done
  *
  * When it is really necessary to create a new vring, it will set the current vq
  * into the reset state. Then call the passed callback to recycle the buffer
@@ -2736,7 +2737,8 @@ EXPORT_SYMBOL_GPL(vring_create_virtqueue_dma);
  *
  */
 int virtqueue_resize(struct virtqueue *_vq, u32 num,
-		     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;
@@ -2753,6 +2755,8 @@ int virtqueue_resize(struct virtqueue *_vq, u32 num,
 	err = virtqueue_disable_and_recycle(_vq, recycle);
 	if (err)
 		return err;
+	if (recycle_done)
+		recycle_done(_vq);
 
 	if (vq->packed_ring)
 		err = virtqueue_resize_packed(_vq, num);

include/linux/virtio.h

@@ -100,7 +100,8 @@ dma_addr_t virtqueue_get_avail_addr(const struct virtqueue *vq);
 dma_addr_t virtqueue_get_used_addr(const struct virtqueue *vq);
 
 int virtqueue_resize(struct virtqueue *vq, u32 num,
-		     void (*recycle)(struct virtqueue *vq, void *buf));
+		     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));