virtio_ring: split: extract the logic of alloc queue

Separate the logic of split to create vring queue.

This feature is required for subsequent virtuqueue reset vring.

Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20220801063902.129329-11-xuanzhuo@linux.alibaba.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 71cc776..5597a9b 100644 (file)
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -948,29 +948,19 @@ static void vring_free_split(struct vring_virtqueue_split *vring_split,
        kfree(vring_split->desc_extra);
 }
 
-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 int vring_alloc_queue_split(struct vring_virtqueue_split *vring_split,
+                                  struct virtio_device *vdev,
+                                  u32 num,
+                                  unsigned int vring_align,
+                                  bool may_reduce_num)
 {
-       struct vring_virtqueue_split vring_split = {};
-       struct virtqueue *vq;
        void *queue = NULL;
        dma_addr_t dma_addr;
-       size_t queue_size_in_bytes;
-       struct vring vring;
 
        /* We assume num is a power of 2. */
        if (num & (num - 1)) {
                dev_warn(&vdev->dev, "Bad virtqueue length %u\n", num);
-               return NULL;
+               return -EINVAL;
        }
 
        /* TODO: allocate each queue chunk individually */
@@ -981,11 +971,11 @@ static struct virtqueue *vring_create_virtqueue_split(
                if (queue)
                        break;
                if (!may_reduce_num)
-                       return NULL;
+                       return -ENOMEM;
        }
 
        if (!num)
-               return NULL;
+               return -ENOMEM;
 
        if (!queue) {
                /* Try to get a single page. You are my only hope! */
@@ -993,21 +983,46 @@ static struct virtqueue *vring_create_virtqueue_split(
                                          &dma_addr, GFP_KERNEL|__GFP_ZERO);
        }
        if (!queue)
-               return NULL;
+               return -ENOMEM;
+
+       vring_init(&vring_split->vring, num, queue, vring_align);
 
-       queue_size_in_bytes = vring_size(num, vring_align);
-       vring_init(&vring_split.vring, num, queue, vring_align);
+       vring_split->queue_dma_addr = dma_addr;
+       vring_split->queue_size_in_bytes = vring_size(num, vring_align);
+
+       return 0;
+}
+
+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)
+{
+       struct vring_virtqueue_split vring_split = {};
+       struct virtqueue *vq;
+       int err;
+
+       err = vring_alloc_queue_split(&vring_split, vdev, num, vring_align,
+                                     may_reduce_num);
+       if (err)
+               return NULL;
 
        vq = __vring_new_virtqueue(index, &vring_split, vdev, weak_barriers,
                                   context, notify, callback, name);
        if (!vq) {
-               vring_free_queue(vdev, queue_size_in_bytes, queue,
-                                dma_addr);
+               vring_free_split(&vring_split, vdev);
                return NULL;
        }
 
-       to_vvq(vq)->split.queue_dma_addr = dma_addr;
-       to_vvq(vq)->split.queue_size_in_bytes = queue_size_in_bytes;
+       to_vvq(vq)->split.queue_dma_addr = vring_split.queue_dma_addr;
+       to_vvq(vq)->split.queue_size_in_bytes = vring_split.queue_size_in_bytes;
        to_vvq(vq)->we_own_ring = true;
 
        return vq;