Re: [PATCH 22/22] vfio: Remove the get_region_info op

[Pranjal Shrivastava <praan@google.com>]

On Thu, Oct 23, 2025 at 08:09:36PM -0300, Jason Gunthorpe wrote:
> No driver uses it now, all are using get_region_info_caps().
> 
> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
> ---
>  drivers/vfio/vfio_main.c | 50 +++++++++++++++++-----------------------
>  include/linux/vfio.h     |  2 --
>  2 files changed, 21 insertions(+), 31 deletions(-)
> 
> diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c
> index 82e7d79b1f9fe2..f911c1980c9420 100644
> --- a/drivers/vfio/vfio_main.c
> +++ b/drivers/vfio/vfio_main.c
> @@ -1263,48 +1263,40 @@ static long vfio_get_region_info(struct vfio_device *device,
>  				 struct vfio_region_info __user *arg)
>  {
>  	unsigned long minsz = offsetofend(struct vfio_region_info, offset);
> +	struct vfio_info_cap caps = { .buf = NULL, .size = 0 };
>  	struct vfio_region_info info = {};
>  	int ret;
>  
> +	if (unlikely(!device->ops->get_region_info_caps))
> +		return -EINVAL;
> +
>  	if (copy_from_user(&info, arg, minsz))
>  		return -EFAULT;
>  	if (info.argsz < minsz)
>  		return -EINVAL;
>  
> -	if (device->ops->get_region_info_caps) {
> -		struct vfio_info_cap caps = { .buf = NULL, .size = 0 };
> +	ret = device->ops->get_region_info_caps(device, &info, &caps);
> +	if (ret)
> +		return ret;

Shall we kfree(caps.buf); before returning?

> -		ret = device->ops->get_region_info_caps(device, &info, &caps);
> -		if (ret)
> -			return ret;
> -
> -		if (caps.size) {
> -			info.flags |= VFIO_REGION_INFO_FLAG_CAPS;
> -			if (info.argsz < sizeof(info) + caps.size) {
> -				info.argsz = sizeof(info) + caps.size;
> -				info.cap_offset = 0;
> -			} else {
> -				vfio_info_cap_shift(&caps, sizeof(info));
> -				if (copy_to_user(arg + 1, caps.buf,
> -						 caps.size)) {
> -					kfree(caps.buf);
> -					return -EFAULT;
> -				}
> -				info.cap_offset = sizeof(info);
> +	if (caps.size) {
> +		info.flags |= VFIO_REGION_INFO_FLAG_CAPS;
> +		if (info.argsz < sizeof(info) + caps.size) {
> +			info.argsz = sizeof(info) + caps.size;
> +			info.cap_offset = 0;
> +		} else {
> +			vfio_info_cap_shift(&caps, sizeof(info));
> +			if (copy_to_user(arg + 1, caps.buf, caps.size)) {
> +				kfree(caps.buf);
> +				return -EFAULT;
>  			}
> -			kfree(caps.buf);
> +			info.cap_offset = sizeof(info);
>  		}
> -
> -		if (copy_to_user(arg, &info, minsz))
> -			return -EFAULT;
> -	} else if (device->ops->get_region_info) {
> -		ret = device->ops->get_region_info(device, arg);
> -		if (ret)
> -			return ret;
> -	} else {
> -		return -EINVAL;
> +		kfree(caps.buf);
>  	}
>  
> +	if (copy_to_user(arg, &info, minsz))
> +		return -EFAULT;
>  	return 0;
>  }
>  
> diff --git a/include/linux/vfio.h b/include/linux/vfio.h
> index 6311ddc837701d..8e1ddb48b9b54e 100644
> --- a/include/linux/vfio.h
> +++ b/include/linux/vfio.h
> @@ -133,8 +133,6 @@ struct vfio_device_ops {
>  			 size_t count, loff_t *size);
>  	long	(*ioctl)(struct vfio_device *vdev, unsigned int cmd,
>  			 unsigned long arg);
> -	int	(*get_region_info)(struct vfio_device *vdev,
> -				   struct vfio_region_info __user *arg);
>  	int	(*get_region_info_caps)(struct vfio_device *vdev,
>  					struct vfio_region_info *info,
>  					struct vfio_info_cap *caps);

Thanks,
Praan