[PATCH v12 09/40] virtio_ring: split: extract the logic of alloc state and extra

Xuan Zhuo
Wed, 20 Jul 2022 03:04:05 -0000

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 at linux.alibaba.com>
---
 drivers/virtio/virtio_ring.c | 54 +++++++++++++++++++++++++-----------
 1 file changed, 38 insertions(+), 16 deletions(-)

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index c7971438bb2c..ef2077e8b38d 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -204,6 +204,7 @@ struct vring_virtqueue {
 #endif
 };

+static struct vring_desc_extra *vring_alloc_desc_extra(unsigned int num);

 /*
  * Helpers.
@@ -939,6 +940,32 @@ static void *virtqueue_detach_unused_buf_split(struct
virtqueue *_vq)
 	return NULL;
 }

+static int vring_alloc_state_extra_split(struct vring_virtqueue_split
*vring_split)
+{
+	struct vring_desc_state_split *state;
+	struct vring_desc_extra *extra;
+	u32 num = vring_split->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_split->desc_state = state;
+	vring_split->desc_extra = extra;
+	return 0;
+
+err_extra:
+	kfree(state);
+err_state:
+	return -ENOMEM;
+}
+
 static void vring_free_split(struct vring_virtqueue_split *vring_split,
 			     struct virtio_device *vdev)
 {
@@ -2233,7 +2260,9 @@ struct virtqueue *__vring_new_virtqueue(unsigned int
index,
 					void (*callback)(struct virtqueue *),
 					const char *name)
 {
+	struct vring_virtqueue_split vring_split = {};
 	struct vring_virtqueue *vq;
+	int err;

 	if (virtio_has_feature(vdev, VIRTIO_F_RING_PACKED))
 		return NULL;
@@ -2274,30 +2303,23 @@ 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_split.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_split);
+	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_split.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