linux-kernel - [RFC PATCH 16/16] virtio_ring: virtqueue_resize() no longer call recycle() directly

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Date:   Sun, 24 Apr 2022 10:40:44 +0800
From:   Xuan Zhuo <xuanzhuo@...ux.alibaba.com>
To:     linux-kernel@...r.kernel.org
Cc:     "Michael S. Tsirkin" <mst@...hat.com>,
        Jason Wang <jasowang@...hat.com>,
        virtualization@...ts.linux-foundation.org
Subject: [RFC PATCH 16/16] virtio_ring: virtqueue_resize() no longer call recycle() directly

virtqueue_resize() no longer calls the recycle callback to release the
buffer. These bufs are reused by virtqueue_resize_* first, and if they
cannot be used, the buffers that cannot be reused will be released

Signed-off-by: Xuan Zhuo <xuanzhuo@...ux.alibaba.com>
---
 drivers/virtio/virtio_ring.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 730c8dded4c7..51dab35a54c9 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -2895,7 +2895,6 @@ int virtqueue_resize(struct virtqueue *_vq, u32 num,
 	struct vring_virtqueue *vq = to_vvq(_vq);
 	struct virtio_device *vdev = vq->vq.vdev;
 	bool packed;
-	void *buf;
 	int err;
 
 	if (!vq->we_own_ring)
@@ -2922,16 +2921,19 @@ int virtqueue_resize(struct virtqueue *_vq, u32 num,
 	if (err)
 		return err;
 
-	while ((buf = virtqueue_detach_unused_buf(_vq)) != NULL)
-		recycle(_vq, buf);
-
 	if (packed)
 		err = virtqueue_resize_packed(_vq, num, recycle);
 	else
 		err = virtqueue_resize_split(_vq, num, recycle);
 
-	if (vdev->config->enable_reset_vq(_vq))
+	if (vdev->config->enable_reset_vq(_vq)) {
 		return -EBUSY;
+	} else if (!err) {
+		num = packed ? vq->packed.vring.num : vq->split.vring.num;
+
+		if (num != vq->vq.num_free)
+			virtqueue_kick(_vq);
+	}
 
 	return err;
 }
-- 
2.31.0