From: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Date: Thu, 10 Aug 2023 12:30:54 +0000 (+0800)
Subject: virtio_ring: introduce virtqueue_reset()
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=ba3e0c47c070c4cf010be9fb1e4eb669c744af11;p=linux.git

virtio_ring: introduce virtqueue_reset()

Introduce virtqueue_reset() to release all buffer inside vq.

Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20230810123057.43407-10-xuanzhuo@linux.alibaba.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 23172d98e48e5..639c20b19e066 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -2812,6 +2812,39 @@ int virtqueue_set_dma_premapped(struct virtqueue *_vq)
 }
 EXPORT_SYMBOL_GPL(virtqueue_set_dma_premapped);
 
+/**
+ * virtqueue_reset - detach and recycle all unused buffers
+ * @_vq: the struct virtqueue we're talking about.
+ * @recycle: callback to recycle unused buffers
+ *
+ * Caller must ensure we don't call this with other virtqueue operations
+ * at the same time (except where noted).
+ *
+ * Returns zero or a negative error.
+ * 0: success.
+ * -EBUSY: Failed to sync with device, vq may not work properly
+ * -ENOENT: Transport or device not supported
+ * -EPERM: Operation not permitted
+ */
+int virtqueue_reset(struct virtqueue *_vq,
+		    void (*recycle)(struct virtqueue *vq, void *buf))
+{
+	struct vring_virtqueue *vq = to_vvq(_vq);
+	int err;
+
+	err = virtqueue_disable_and_recycle(_vq, recycle);
+	if (err)
+		return err;
+
+	if (vq->packed_ring)
+		virtqueue_reinit_packed(vq);
+	else
+		virtqueue_reinit_split(vq);
+
+	return virtqueue_enable_after_reset(_vq);
+}
+EXPORT_SYMBOL_GPL(virtqueue_reset);
+
 /* Only available for split ring */
 struct virtqueue *vring_new_virtqueue(unsigned int index,
 				      unsigned int num,
diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index bd55a05eec04f..49a640e0a6f4d 100644
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h
@@ -99,6 +99,8 @@ 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));
+int virtqueue_reset(struct virtqueue *vq,
+		    void (*recycle)(struct virtqueue *vq, void *buf));
 
 /**
  * struct virtio_device - representation of a device using virtio