Virtualization - Nov 2016 - [PATCH] virtio_mmio: Set dev.release() to avoid warning

From: Yuan Liu <liuyuan at google.com>

Fix a warning thrown from virtio_mmio_remove():
Device 'virtio0' does not have a release() function

The fix is according to virtio_pci_probe() of
drivers/virtio/virtio_pci_common.c

Signed-off-by: Yuan Liu <liuyuan at google.com>
---
 drivers/virtio/virtio_mmio.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
index 48bfea9..d47a2fc 100644
--- a/drivers/virtio/virtio_mmio.c
+++ b/drivers/virtio/virtio_mmio.c
@@ -489,6 +489,7 @@ static const struct virtio_config_ops virtio_mmio_config_ops
= {
 };
 
 
+static void virtio_mmio_release_dev_empty(struct device *_d) {}
 
 /* Platform device */
 
@@ -511,6 +512,7 @@ static int virtio_mmio_probe(struct platform_device *pdev)
 		return  -ENOMEM;
 
 	vm_dev->vdev.dev.parent = &pdev->dev;
+	vm_dev->vdev.dev.release = virtio_mmio_release_dev_empty;
 	vm_dev->vdev.config = &virtio_mmio_config_ops;
 	vm_dev->pdev = pdev;
 	INIT_LIST_HEAD(&vm_dev->virtqueues);
-- 
2.8.0.rc3.226.g39d4020

On 2016?11?24? 08:31, Yuan Liu wrote:
> From: Yuan Liu <liuyuan at google.com>
>
> Fix a warning thrown from virtio_mmio_remove():
> Device 'virtio0' does not have a release() function
>
> The fix is according to virtio_pci_probe() of
> drivers/virtio/virtio_pci_common.c
>
> Signed-off-by: Yuan Liu <liuyuan at google.com>
> ---
>   drivers/virtio/virtio_mmio.c | 2 ++
>   1 file changed, 2 insertions(+)
>
> diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
> index 48bfea9..d47a2fc 100644
> --- a/drivers/virtio/virtio_mmio.c
> +++ b/drivers/virtio/virtio_mmio.c
> @@ -489,6 +489,7 @@ static const struct virtio_config_ops
virtio_mmio_config_ops = {
>   };
>   
>   
> +static void virtio_mmio_release_dev_empty(struct device *_d) {}
Do we need to free vm_dev here?
>   
>   /* Platform device */
>   
> @@ -511,6 +512,7 @@ static int virtio_mmio_probe(struct platform_device
*pdev)
>   		return  -ENOMEM;
>   
>   	vm_dev->vdev.dev.parent = &pdev->dev;
> +	vm_dev->vdev.dev.release = virtio_mmio_release_dev_empty;
>   	vm_dev->vdev.config = &virtio_mmio_config_ops;
>   	vm_dev->pdev = pdev;
>   	INIT_LIST_HEAD(&vm_dev->virtqueues);

I think not. In virtio_pci_common, vp_dev is allocated by kzalloc so a
kfree is needed. Here vm_dev is allocated by devm_kmalloc which is
"automatically freed on driver detach" from the comment
(drivers/base/devres.c:769).

On Thu, Nov 24, 2016 at 6:37 PM, Jason Wang <jasowang at redhat.com>
wrote:
>
>
> On 2016?11?24? 08:31, Yuan Liu wrote:
>
>> From: Yuan Liu <liuyuan at google.com>
>>
>> Fix a warning thrown from virtio_mmio_remove():
>> Device 'virtio0' does not have a release() function
>>
>> The fix is according to virtio_pci_probe() of
>> drivers/virtio/virtio_pci_common.c
>>
>> Signed-off-by: Yuan Liu <liuyuan at google.com>
>> ---
>>   drivers/virtio/virtio_mmio.c | 2 ++
>>   1 file changed, 2 insertions(+)
>>
>> diff --git a/drivers/virtio/virtio_mmio.c
b/drivers/virtio/virtio_mmio.c
>> index 48bfea9..d47a2fc 100644
>> --- a/drivers/virtio/virtio_mmio.c
>> +++ b/drivers/virtio/virtio_mmio.c
>> @@ -489,6 +489,7 @@ static const struct virtio_config_ops
>> virtio_mmio_config_ops = {
>>   };
>>     +static void virtio_mmio_release_dev_empty(struct device *_d) {}
>>
>
> Do we need to free vm_dev here?
>
>
>     /* Platform device */
>>   @@ -511,6 +512,7 @@ static int virtio_mmio_probe(struct
platform_device
>> *pdev)
>>                 return  -ENOMEM;
>>         vm_dev->vdev.dev.parent = &pdev->dev;
>> +       vm_dev->vdev.dev.release = virtio_mmio_release_dev_empty;
>>         vm_dev->vdev.config = &virtio_mmio_config_ops;
>>         vm_dev->pdev = pdev;
>>         INIT_LIST_HEAD(&vm_dev->virtqueues);
>>
>
>
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