[PATCH v10 11/41] virtio_ring: split: extract the logic of alloc state and extra

[Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>]

Separate the logic of creating desc_state, desc_extra, and subsequent
patches will call it independently.

Since only the structure vring is passed into __vring_new_virtqueue(),
when creating the function vring_alloc_state_extra_split(), we prefer to
use vring_virtqueue_split as a parameter, and it will be more convenient
to pass vring_virtqueue_split to some subsequent functions.

So a new vring_virtqueue_split variable is added in
__vring_new_virtqueue().

Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
---
 drivers/virtio/virtio_ring.c | 58 +++++++++++++++++++++++++-----------
 1 file changed, 40 insertions(+), 18 deletions(-)

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 7399af292dcb..ef775154536e 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -202,6 +202,7 @@ struct vring_virtqueue {
 #endif
 };
 
+static struct vring_desc_extra *vring_alloc_desc_extra(unsigned int num);
 
 /*
  * Helpers.
@@ -934,6 +935,32 @@ static void *virtqueue_detach_unused_buf_split(struct virtqueue *_vq)
 	return NULL;
 }
 
+static int vring_alloc_state_extra_split(struct vring_virtqueue_split *vring)
+{
+	struct vring_desc_state_split *state;
+	struct vring_desc_extra *extra;
+	u32 num = vring->vring.num;
+
+	state = kmalloc_array(num, sizeof(struct vring_desc_state_split), GFP_KERNEL);
+	if (!state)
+		goto err_state;
+
+	extra = vring_alloc_desc_extra(num);
+	if (!extra)
+		goto err_extra;
+
+	memset(state, 0, num * sizeof(struct vring_desc_state_split));
+
+	vring->desc_state = state;
+	vring->desc_extra = extra;
+	return 0;
+
+err_extra:
+	kfree(state);
+err_state:
+	return -ENOMEM;
+}
+
 static void vring_free_split(struct vring_virtqueue_split *vring,
 			     struct virtio_device *vdev)
 {
@@ -2194,7 +2221,7 @@ EXPORT_SYMBOL_GPL(vring_interrupt);
 
 /* Only available for split ring */
 struct virtqueue *__vring_new_virtqueue(unsigned int index,
-					struct vring vring,
+					struct vring _vring,
 					struct virtio_device *vdev,
 					bool weak_barriers,
 					bool context,
@@ -2202,7 +2229,9 @@ struct virtqueue *__vring_new_virtqueue(unsigned int index,
 					void (*callback)(struct virtqueue *),
 					const char *name)
 {
+	struct vring_virtqueue_split vring = {};
 	struct vring_virtqueue *vq;
+	int err;
 
 	if (virtio_has_feature(vdev, VIRTIO_F_RING_PACKED))
 		return NULL;
@@ -2226,7 +2255,7 @@ struct virtqueue *__vring_new_virtqueue(unsigned int index,
 	vq->split.queue_dma_addr = 0;
 	vq->split.queue_size_in_bytes = 0;
 
-	vq->split.vring = vring;
+	vq->split.vring = _vring;
 	vq->split.avail_flags_shadow = 0;
 	vq->split.avail_idx_shadow = 0;
 
@@ -2238,30 +2267,23 @@ struct virtqueue *__vring_new_virtqueue(unsigned int index,
 					vq->split.avail_flags_shadow);
 	}
 
-	vq->split.desc_state = kmalloc_array(vring.num,
-			sizeof(struct vring_desc_state_split), GFP_KERNEL);
-	if (!vq->split.desc_state)
-		goto err_state;
+	vring.vring = _vring;
 
-	vq->split.desc_extra = vring_alloc_desc_extra(vring.num);
-	if (!vq->split.desc_extra)
-		goto err_extra;
+	err = vring_alloc_state_extra_split(&vring);
+	if (err) {
+		kfree(vq);
+		return NULL;
+	}
 
-	memset(vq->split.desc_state, 0, vring.num *
-			sizeof(struct vring_desc_state_split));
+	vq->split.desc_state = vring.desc_state;
+	vq->split.desc_extra = vring.desc_extra;
 
-	virtqueue_init(vq, vq->split.vring.num);
+	virtqueue_init(vq, vring.vring.num);
 
 	spin_lock(&vdev->vqs_list_lock);
 	list_add_tail(&vq->vq.list, &vdev->vqs);
 	spin_unlock(&vdev->vqs_list_lock);
 	return &vq->vq;
-
-err_extra:
-	kfree(vq->split.desc_state);
-err_state:
-	kfree(vq);
-	return NULL;
 }
 EXPORT_SYMBOL_GPL(__vring_new_virtqueue);
 
-- 
2.31.0