[PATCH v9 06/32] virtio_ring: split: extract the logic of alloc queue

[Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>]

Separate the logic of split to create vring queue.

This feature is required for subsequent virtuqueue reset vring.

Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
---
 drivers/virtio/virtio_ring.c | 53 ++++++++++++++++++++++++------------
 1 file changed, 36 insertions(+), 17 deletions(-)

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 33fddfb907a6..72d5ae063fa0 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -915,23 +915,15 @@ static void *virtqueue_detach_unused_buf_split(struct virtqueue *_vq)
 	return NULL;
 }
 
-static struct virtqueue *vring_create_virtqueue_split(
-	unsigned int index,
-	unsigned int num,
-	unsigned int vring_align,
-	struct virtio_device *vdev,
-	bool weak_barriers,
-	bool may_reduce_num,
-	bool context,
-	bool (*notify)(struct virtqueue *),
-	void (*callback)(struct virtqueue *),
-	const char *name)
+static void *vring_alloc_queue_split(struct virtio_device *vdev,
+				     dma_addr_t *dma_addr,
+				     u32 *n,
+				     unsigned int vring_align,
+				     bool weak_barriers,
+				     bool may_reduce_num)
 {
-	struct virtqueue *vq;
 	void *queue = NULL;
-	dma_addr_t dma_addr;
-	size_t queue_size_in_bytes;
-	struct vring vring;
+	u32 num = *n;
 
 	/* We assume num is a power of 2. */
 	if (num & (num - 1)) {
@@ -942,7 +934,7 @@ static struct virtqueue *vring_create_virtqueue_split(
 	/* TODO: allocate each queue chunk individually */
 	for (; num && vring_size(num, vring_align) > PAGE_SIZE; num /= 2) {
 		queue = vring_alloc_queue(vdev, vring_size(num, vring_align),
-					  &dma_addr,
+					  dma_addr,
 					  GFP_KERNEL|__GFP_NOWARN|__GFP_ZERO);
 		if (queue)
 			break;
@@ -956,11 +948,38 @@ static struct virtqueue *vring_create_virtqueue_split(
 	if (!queue) {
 		/* Try to get a single page. You are my only hope! */
 		queue = vring_alloc_queue(vdev, vring_size(num, vring_align),
-					  &dma_addr, GFP_KERNEL|__GFP_ZERO);
+					  dma_addr, GFP_KERNEL|__GFP_ZERO);
 	}
 	if (!queue)
 		return NULL;
 
+	*n = num;
+	return queue;
+}
+
+static struct virtqueue *vring_create_virtqueue_split(
+	unsigned int index,
+	unsigned int num,
+	unsigned int vring_align,
+	struct virtio_device *vdev,
+	bool weak_barriers,
+	bool may_reduce_num,
+	bool context,
+	bool (*notify)(struct virtqueue *),
+	void (*callback)(struct virtqueue *),
+	const char *name)
+{
+	size_t queue_size_in_bytes;
+	struct virtqueue *vq;
+	dma_addr_t dma_addr;
+	struct vring vring;
+	void *queue;
+
+	queue = vring_alloc_queue_split(vdev, &dma_addr, &num, vring_align,
+					weak_barriers, may_reduce_num);
+	if (!queue)
+		return NULL;
+
 	queue_size_in_bytes = vring_size(num, vring_align);
 	vring_init(&vring, num, queue, vring_align);
 
-- 
2.31.0