Re: [PATCH] uacce: add print information if not enable sva

[Greg KH <gregkh@linuxfoundation.org>]

On Fri, Jun 04, 2021 at 03:46:09PM +0800, Kai Ye wrote:
> Add print information necessary if user not enable sva.
> 
> Signed-off-by: Kai Ye <yekai13@huawei.com>
> ---
>  drivers/misc/uacce/uacce.c | 11 +++++++++--
>  1 file changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/misc/uacce/uacce.c b/drivers/misc/uacce/uacce.c
> index bae18ef0..fe38af8 100644
> --- a/drivers/misc/uacce/uacce.c
> +++ b/drivers/misc/uacce/uacce.c
> @@ -387,15 +387,22 @@ static void uacce_release(struct device *dev)
>  
>  static unsigned int uacce_enable_sva(struct device *parent, unsigned int flags)
>  {
> +	int ret;
> +
>  	if (!(flags & UACCE_DEV_SVA))
>  		return flags;
>  
>  	flags &= ~UACCE_DEV_SVA;
>  
> -	if (iommu_dev_enable_feature(parent, IOMMU_DEV_FEAT_IOPF))
> +	ret = iommu_dev_enable_feature(parent, IOMMU_DEV_FEAT_IOPF);
> +	if (ret) {
> +		dev_err(parent, "failed to enable IOPF feature! ret = %d\n", ret);

Why is this needed?  Has this ever happened in real life such that the
log message is now required?



>  		return flags;
> +	}
>  
> -	if (iommu_dev_enable_feature(parent, IOMMU_DEV_FEAT_SVA)) {
> +	ret = iommu_dev_enable_feature(parent, IOMMU_DEV_FEAT_SVA);
> +	if (ret) {
> +		dev_err(parent, "failed to enable SVA feature! ret = %d\n", ret);

Same here, does this happen in real systems?

thanks,

greg k-h