[SRU][O][PATCH 2/3] virtio_ring: add a func argument 'recycle_done' to virtqueue_resize()

[Koichiro Den]

BugLink: https://bugs.launchpad.net/bugs/2089684

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 at vger.kernel.org> # v6.11+
Signed-off-by: Koichiro Den <koichiro.den at canonical.com>
Acked-by: Jason Wang <jasowang at redhat.com>
Reviewed-by: Xuan Zhuo <xuanzhuo at linux.alibaba.com>
Signed-off-by: Paolo Abeni <pabeni at redhat.com>
(cherry picked from commit 8d6712c892019b9b9dc5c7039edd3c9d770b510b linux-next)
Signed-off-by: Koichiro Den <koichiro.den at canonical.com>
---
 drivers/net/virtio_net.c     | 4 ++--
 drivers/virtio/virtio_ring.c | 6 +++++-
 include/linux/virtio.h       | 3 ++-
 3 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index ff47688a80cd..905e84b10abe 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -3139,7 +3139,7 @@ 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);
 
@@ -3202,7 +3202,7 @@ 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);
 
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index be7309b1e860..847b675be7dd 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/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);
diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index 306137a15d07..73c8922e69e0 100644
--- a/include/linux/virtio.h
+++ b/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));
 
-- 
2.43.0