[PATCH v2 1/1] virtio_balloon: pr_dev_info.report initialization cleanup

[PATCH v2 1/1] virtio_balloon: pr_dev_info.report initialization cleanup

[Dongli Zhang]

The virtio_balloon vb->pr_dev_info is used as argument for
page_reporting_register() only when the VIRTIO_BALLOON_F_REPORTING feature
is available. There is no need to initialize vb->pr_dev_info.report if this
feature is unavailable.

Similarly, the Hyper-V balloon driver sets dm_device.pr_dev_info.report
only when the corresponding feature is present. If
page_reporting_register() fails, it even resets pr_dev_info.report back to
NULL.

No functional change. Only for cleanup.

Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
---
Changed since v1:
  - Add commit message to explain why we would want to do that.

 drivers/virtio/virtio_balloon.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index 74fe59f5a78c..0c39f2415324 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -1034,7 +1034,6 @@ static int virtballoon_probe(struct virtio_device *vdev)
 				 poison_val, &poison_val);
 	}
 
-	vb->pr_dev_info.report = virtballoon_free_page_report;
 	if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_REPORTING)) {
 		unsigned int capacity;
 
@@ -1044,6 +1043,8 @@ static int virtballoon_probe(struct virtio_device *vdev)
 			goto out_unregister_oom;
 		}
 
+		vb->pr_dev_info.report = virtballoon_free_page_report;
+
 		/*
 		 * The default page reporting order is @pageblock_order, which
 		 * corresponds to 512MB in size on ARM64 when 64KB base page
-- 
2.39.3

Re: [PATCH v2 1/1] virtio_balloon: pr_dev_info.report initialization cleanup

[David Hildenbrand (Red Hat)]

On 12/20/25 01:30, Dongli Zhang wrote:
> The virtio_balloon vb->pr_dev_info is used as argument for
> page_reporting_register() only when the VIRTIO_BALLOON_F_REPORTING feature
> is available. There is no need to initialize vb->pr_dev_info.report if this
> feature is unavailable.
> 
> Similarly, the Hyper-V balloon driver sets dm_device.pr_dev_info.report
> only when the corresponding feature is present. If
> page_reporting_register() fails, it even resets pr_dev_info.report back to
> NULL.
> 
> No functional change. Only for cleanup.
> 
> Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
> ---
> Changed since v1:
>    - Add commit message to explain why we would want to do that.
> 
>   drivers/virtio/virtio_balloon.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
> index 74fe59f5a78c..0c39f2415324 100644
> --- a/drivers/virtio/virtio_balloon.c
> +++ b/drivers/virtio/virtio_balloon.c
> @@ -1034,7 +1034,6 @@ static int virtballoon_probe(struct virtio_device *vdev)
>   				 poison_val, &poison_val);
>   	}
>   
> -	vb->pr_dev_info.report = virtballoon_free_page_report;
>   	if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_REPORTING)) {
>   		unsigned int capacity;
>   
> @@ -1044,6 +1043,8 @@ static int virtballoon_probe(struct virtio_device *vdev)
>   			goto out_unregister_oom;
>   		}
>   
> +		vb->pr_dev_info.report = virtballoon_free_page_report;
> +
>   		/*
>   		 * The default page reporting order is @pageblock_order, which
>   		 * corresponds to 512MB in size on ARM64 when 64KB base page

Acked-by: David Hildenbrand (Red Hat) <david@kernel.org>

-- 
Cheers

David