[PATCH] virtio_ring: reset IN_ORDER state in virtqueue_init()

[lirongqing <lirongqing@baidu.com>]

From: Li RongQing <lirongqing@baidu.com>

The IN_ORDER feature uses additional software state to track the next
available descriptor and in-flight descriptor batches.

virtqueue_init() resets the common virtqueue state, but free_head and
batch_last.id are initialized only when the virtqueue is created. When
an IN_ORDER virtqueue is reset, these fields can retain state from the
previous queue instance.

Reset free_head and invalidate batch_last when initializing an IN_ORDER
virtqueue. Keep this in virtqueue_init() so the state is initialized
consistently for both newly created and reset virtqueues.

Fixes: f6a15d854986 ("virtio_ring: add in order support")
Signed-off-by: Li RongQing <lirongqing@baidu.com>
---
 drivers/virtio/virtio_ring.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index db678f5..d0dc464 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -559,6 +559,11 @@ static void virtqueue_init(struct vring_virtqueue *vq, u32 num)
 	vq->in_use = false;
 	vq->last_add_time_valid = false;
 #endif
+
+	if (virtqueue_is_in_order(vq)) {
+		vq->free_head = 0;
+		vq->batch_last.id = UINT_MAX;
+	}
 }
 
 
-- 
2.9.4