[PATCH v10 19/41] virtio_ring: packed: extract the logic of alloc state and extra

[Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>]

Separate the logic for alloc desc_state and desc_extra, which will
be called separately by subsequent patches.

Use struct vring_packed to pass desc_state, desc_extra.

Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
---
 drivers/virtio/virtio_ring.c | 48 +++++++++++++++++++++++++-----------
 1 file changed, 34 insertions(+), 14 deletions(-)

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 4b1a7a940012..33271535c839 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -1879,6 +1879,33 @@ static int vring_alloc_queue_packed(struct vring_virtqueue_packed *vring,
 	return -ENOMEM;
 }
 
+static int vring_alloc_state_extra_packed(struct vring_virtqueue_packed *vring)
+{
+	struct vring_desc_state_packed *state;
+	struct vring_desc_extra *extra;
+	u32 num = vring->vring.num;
+
+	state = kmalloc_array(num, sizeof(struct vring_desc_state_packed), GFP_KERNEL);
+	if (!state)
+		goto err_desc_state;
+
+	memset(state, 0, num * sizeof(struct vring_desc_state_packed));
+
+	extra = vring_alloc_desc_extra(num);
+	if (!extra)
+		goto err_desc_extra;
+
+	vring->desc_state = state;
+	vring->desc_extra = extra;
+
+	return 0;
+
+err_desc_extra:
+	kfree(state);
+err_desc_state:
+	return -ENOMEM;
+}
+
 static struct virtqueue *vring_create_virtqueue_packed(
 	unsigned int index,
 	unsigned int num,
@@ -1893,6 +1920,7 @@ static struct virtqueue *vring_create_virtqueue_packed(
 {
 	struct vring_virtqueue_packed vring = {};
 	struct vring_virtqueue *vq;
+	int err;
 
 	if (vring_alloc_queue_packed(&vring, vdev, num))
 		goto err_ring;
@@ -1929,21 +1957,15 @@ static struct virtqueue *vring_create_virtqueue_packed(
 	vq->packed.event_flags_shadow = 0;
 	vq->packed.avail_used_flags = 1 << VRING_PACKED_DESC_F_AVAIL;
 
-	vq->packed.desc_state = kmalloc_array(num,
-			sizeof(struct vring_desc_state_packed),
-			GFP_KERNEL);
-	if (!vq->packed.desc_state)
-		goto err_desc_state;
+	err = vring_alloc_state_extra_packed(&vring);
+	if (err)
+		goto err_state_extra;
 
-	memset(vq->packed.desc_state, 0,
-		num * sizeof(struct vring_desc_state_packed));
+	vq->packed.desc_state = vring.desc_state;
+	vq->packed.desc_extra = vring.desc_extra;
 
 	virtqueue_init(vq, num);
 
-	vq->packed.desc_extra = vring_alloc_desc_extra(num);
-	if (!vq->packed.desc_extra)
-		goto err_desc_extra;
-
 	/* No callback?  Tell other side not to bother us. */
 	if (!callback) {
 		vq->packed.event_flags_shadow = VRING_PACKED_EVENT_FLAG_DISABLE;
@@ -1956,9 +1978,7 @@ static struct virtqueue *vring_create_virtqueue_packed(
 	spin_unlock(&vdev->vqs_list_lock);
 	return &vq->vq;
 
-err_desc_extra:
-	kfree(vq->packed.desc_state);
-err_desc_state:
+err_state_extra:
 	kfree(vq);
 err_vq:
 	vring_free_packed(&vring, vdev);
-- 
2.31.0