Re: [PATCHv2 4/4] staging: android: ion: Add ioctl to query available heaps

[Greg Kroah-Hartman]

On Thu, Sep 01, 2016 at 03:40:44PM -0700, Laura Abbott wrote:
> 
> Ion clients currently lack a good method to determine what
> heaps are available and what ids they map to. This leads
> to tight coupling between user and kernel space and headaches.
> Add a query ioctl to let userspace know the availability of
> heaps.
> 
> Signed-off-by: Laura Abbott <labbott@xxxxxxxxxx>
> ---
>  drivers/staging/android/ion/ion-ioctl.c | 11 +++++++++
>  drivers/staging/android/ion/ion.c       | 44 +++++++++++++++++++++++++++++++++
>  drivers/staging/android/ion/ion_priv.h  |  3 +++
>  drivers/staging/android/uapi/ion.h      | 39 +++++++++++++++++++++++++++++
>  4 files changed, 97 insertions(+)
> 
> diff --git a/drivers/staging/android/ion/ion-ioctl.c b/drivers/staging/android/ion/ion-ioctl.c
> index 53b9520..e76d517 100644
> --- a/drivers/staging/android/ion/ion-ioctl.c
> +++ b/drivers/staging/android/ion/ion-ioctl.c
> @@ -28,6 +28,7 @@ union ion_ioctl_arg {
>  	struct ion_handle_data handle;
>  	struct ion_custom_data custom;
>  	struct ion_abi_version abi_version;
> +	struct ion_heap_query query;
>  };
>  
>  static int validate_ioctl_arg(unsigned int cmd, union ion_ioctl_arg *arg)
> @@ -38,6 +39,11 @@ static int validate_ioctl_arg(unsigned int cmd, union ion_ioctl_arg *arg)
>  	case ION_IOC_ABI_VERSION:
>  		ret = arg->abi_version.reserved != 0;
>  		break;
> +	case ION_IOC_HEAP_QUERY:
> +		ret = arg->query.reserved0 != 0;
> +		ret |= arg->query.reserved1 != 0;
> +		ret |= arg->query.reserved2 != 0;
> +		break;
>  	default:
>  		break;
>  	}
> @@ -162,6 +168,11 @@ long ion_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
>  		data.abi_version.abi_version = ION_ABI_VERSION;
>  		break;
>  	}
> +	case ION_IOC_HEAP_QUERY:
> +	{
> +		ret = ion_query_heaps(client, &data.query);
> +		break;
> +	}

Minor nit, the { } aren't needed here.  Yeah, I know the other cases
have them, but they aren't all needed there either, no need to keep
copying bad code style :)



>  	default:
>  		return -ENOTTY;
>  	}
> diff --git a/drivers/staging/android/ion/ion.c b/drivers/staging/android/ion/ion.c
> index 975b48f..91b765c 100644
> --- a/drivers/staging/android/ion/ion.c
> +++ b/drivers/staging/android/ion/ion.c
> @@ -1174,6 +1174,49 @@ int ion_sync_for_device(struct ion_client *client, int fd)
>  	return 0;
>  }
>  
> +int ion_query_heaps(struct ion_client *client, struct ion_heap_query *query)
> +{
> +	struct ion_device *dev = client->dev;
> +	struct ion_heap_data __user *buffer =
> +		(struct ion_heap_data __user *)query->heaps;

Shouldn't query be marked as __user instead of having this cast?

> +	int ret = -EINVAL, cnt = 0, max_cnt;
> +	struct ion_heap *heap;
> +	struct ion_heap_data hdata;
> +
> +	memset(&hdata, 0, sizeof(hdata));
> +
> +	down_read(&dev->lock);
> +	if (!buffer) {
> +		query->cnt = dev->heap_cnt;

Wait, query is __user?

I think the mixing of user/kernel pointers here isn't quite right, or I
just really can't figure it out...

And kbuild didn't seem to like this patch either :(

But your first 2 patches are great, I'll queue them up later today.

thanks,

greg k-h