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Date:   Fri, 2 Jun 2023 18:06:49 +0800
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Subject: Re: [PATCH v2 1/2] iommu/vt-d: Handle the failure case of
 dmar_reenable_qi()
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To:     Robin Murphy <robin.murphy@arm.com>, <dwmw2@infradead.org>,
        <baolu.lu@linux.intel.com>, <joro@8bytes.org>, <will@kernel.org>
CC:     <iommu@lists.linux.dev>, <linux-kernel@vger.kernel.org>
References: <20230602020520.224465-1-yanfei.xu@intel.com>
 <20230602020520.224465-2-yanfei.xu@intel.com>
 <88a9afd9-eb2d-55b0-e65e-dec209a5bba3@arm.com>
From:   Yanfei Xu <yanfei.xu@intel.com>
In-Reply-To: <88a9afd9-eb2d-55b0-e65e-dec209a5bba3@arm.com>
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On 6/2/2023 5:27 PM, Robin Murphy wrote:
> 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@intel.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.
>
Oh, you are right. Will correct it.

Thanks,
Yanfei

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