linux-kernel - Re: [PATCH v2 1/2] iommu/vt-d: Handle the failure case of dmar_reenable

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Date:   Fri, 2 Jun 2023 10:27:39 +0100
From:   Robin Murphy <robin.murphy@....com>
To:     Yanfei Xu <yanfei.xu@...el.com>, dwmw2@...radead.org,
        baolu.lu@...ux.intel.com, joro@...tes.org, will@...nel.org
Cc:     iommu@...ts.linux.dev, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 1/2] iommu/vt-d: Handle the failure case of
 dmar_reenable_qi()

On 2023-06-02 03:05, Yanfei Xu wrote:
> dmar_reenable_qi() may not succeed. Check and return when it fails.
> 
> Signed-off-by: Yanfei Xu <yanfei.xu@...el.com>
> ---
>   drivers/iommu/intel/iommu.c | 8 ++++++--
>   1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
> index 8096273b034c..e9188d045609 100644
> --- a/drivers/iommu/intel/iommu.c
> +++ b/drivers/iommu/intel/iommu.c
> @@ -2967,10 +2967,14 @@ static int init_iommu_hw(void)
>   {
>   	struct dmar_drhd_unit *drhd;
>   	struct intel_iommu *iommu = NULL;
> +	int ret;
>   
> -	for_each_active_iommu(iommu, drhd)
> +	for_each_active_iommu(iommu, drhd) {
>   		if (iommu->qi)
> -			dmar_reenable_qi(iommu);
> +			ret = dmar_reenable_qi(iommu);
> +		if (ret)

Nit: either this should be inside the previous condition, or you need to 
initialise ret to 0.

Thanks,
Robin.

> +			return ret;
> +	}
>   
>   	for_each_iommu(iommu, drhd) {
>   		if (drhd->ignored) {