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 23172d98e48e54309b240e2287f7104877ea2866..639c20b19e0660debb6d10c43cdb5596fcf563d4 100644 (file)
--- 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 bd55a05eec04f7f383e284ef0173829010e32a88..49a640e0a6f4d7debfcb814752f7fd6ca5b3acee 100644 (file)
--- 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