Re: [PATCH v9 07/32] virtio_ring: split: extract the logic of alloc state and extra

[Jason Wang]

在 2022/4/6 上午11:43, Xuan Zhuo 写道:
Separate the logic of creating desc_state, desc_extra, and subsequent
patches will call it independently.
Signed-off-by: Xuan Zhuo <xuanz...@linux.alibaba.com>
---
  drivers/virtio/virtio_ring.c | 53 ++++++++++++++++++++++++++----------
  1 file changed, 38 insertions(+), 15 deletions(-)

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 72d5ae063fa0..6de67439cb57 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -198,6 +198,7 @@ struct vring_virtqueue {
  #endif
  };
  
+static struct vring_desc_extra *vring_alloc_desc_extra(unsigned int num);
  
  /*
   * Helpers.
@@ -915,6 +916,33 @@ static void *virtqueue_detach_unused_buf_split(struct 
virtqueue *_vq)
        return NULL;
  }
  
+static int vring_alloc_state_extra_split(u32 num,
+                                        struct vring_desc_state_split 
**desc_state,
+                                        struct vring_desc_extra **desc_extra)
+{
+       struct vring_desc_state_split *state;
+       struct vring_desc_extra *extra;
+
+       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));
+
+       *desc_state = state;
+       *desc_extra = extra;
+       return 0;
+
+err_extra:
+       kfree(state);
+err_state:
+       return -ENOMEM;
+}
+
  static void *vring_alloc_queue_split(struct virtio_device *vdev,
                                     dma_addr_t *dma_addr,
                                     u32 *n,
@@ -2196,7 +2224,10 @@ struct virtqueue *__vring_new_virtqueue(unsigned int 
index,
                                        void (*callback)(struct virtqueue *),
                                        const char *name)
  {
+       struct vring_desc_state_split *state;
+       struct vring_desc_extra *extra;
        struct vring_virtqueue *vq;
+       int err;
  
  	if (virtio_has_feature(vdev, VIRTIO_F_RING_PACKED))
                return NULL;
@@ -2246,30 +2277,22 @@ 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;
+       err = vring_alloc_state_extra_split(vring.num, &state, &extra);


Nit: we can pass e.g &vq->split.desc_state here to avoid extra temp 
variable and assignment.

Other looks good.

Thanks


+       if (err) {
+               kfree(vq);
+               return NULL;
+       }
  
-	vq->split.desc_extra = vring_alloc_desc_extra(vring.num);
-       if (!vq->split.desc_extra)
-               goto err_extra;
+       vq->split.desc_state = state;
+       vq->split.desc_extra = extra;
  
  	/* Put everything in free lists. */
        vq->free_head = 0;
-       memset(vq->split.desc_state, 0, vring.num *
-                       sizeof(struct vring_desc_state_split));
  
  	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);
  


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