linux-kernel - Re: [PATCH v9 13/14] iommu: Improve iopf_queue_remove

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Message-ID: <91c2add2-3015-4935-9dd5-d4e42aff473a@linux.intel.com>
Date: Tue, 9 Jan 2024 11:36:19 +0800
From: Baolu Lu <baolu.lu@...ux.intel.com>
To: Jason Gunthorpe <jgg@...pe.ca>
Cc: baolu.lu@...ux.intel.com, Joerg Roedel <joro@...tes.org>,
 Will Deacon <will@...nel.org>, Robin Murphy <robin.murphy@....com>,
 Kevin Tian <kevin.tian@...el.com>,
 Jean-Philippe Brucker <jean-philippe@...aro.org>,
 Nicolin Chen <nicolinc@...dia.com>, Yi Liu <yi.l.liu@...el.com>,
 Jacob Pan <jacob.jun.pan@...ux.intel.com>,
 Longfang Liu <liulongfang@...wei.com>, Yan Zhao <yan.y.zhao@...el.com>,
 iommu@...ts.linux.dev, kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v9 13/14] iommu: Improve iopf_queue_remove_device()

On 1/6/24 12:25 AM, Jason Gunthorpe wrote:
> On Wed, Dec 20, 2023 at 09:23:31AM +0800, Lu Baolu wrote:
>> -int iopf_queue_remove_device(struct iopf_queue *queue, struct device *dev)
>> +void iopf_queue_remove_device(struct iopf_queue *queue, struct device *dev)
>>   {
>> -	int ret = 0;
>>   	struct iopf_fault *iopf, *next;
>> +	struct iommu_page_response resp;
>>   	struct dev_iommu *param = dev->iommu;
>>   	struct iommu_fault_param *fault_param;
>> +	const struct iommu_ops *ops = dev_iommu_ops(dev);
>>   
>>   	mutex_lock(&queue->lock);
>>   	mutex_lock(&param->lock);
>>   	fault_param = rcu_dereference_check(param->fault_param,
>>   					    lockdep_is_held(&param->lock));
>> -	if (!fault_param) {
>> -		ret = -ENODEV;
>> -		goto unlock;
>> -	}
>> -
>> -	if (fault_param->queue != queue) {
>> -		ret = -EINVAL;
>> -		goto unlock;
>> -	}
>>   
>> -	if (!list_empty(&fault_param->faults)) {
>> -		ret = -EBUSY;
>> +	if (WARN_ON(!fault_param || fault_param->queue != queue))
>>   		goto unlock;
>> -	}
>> -
>> -	list_del(&fault_param->queue_list);
>>   
>> -	/* Just in case some faults are still stuck */
>> +	mutex_lock(&fault_param->lock);
>>   	list_for_each_entry_safe(iopf, next, &fault_param->partial, list)
>>   		kfree(iopf);
>>   
>> +	list_for_each_entry_safe(iopf, next, &fault_param->faults, list) {
>> +		memset(&resp, 0, sizeof(struct iommu_page_response));
>> +		resp.pasid = iopf->fault.prm.pasid;
>> +		resp.grpid = iopf->fault.prm.grpid;
>> +		resp.code = IOMMU_PAGE_RESP_INVALID;
> 
> I would probably move the resp and iopf variables into here:
> 
> 		struct iopf_fault *iopf = &group->last_fault;
> 		struct iommu_page_response resp = {
> 			.pasid = iopf->fault.prm.pasid,
> 			.grpid = iopf->fault.prm.grpid,
> 			.code = IOMMU_PAGE_RESP_INVALID
> 		};
> 
> (and call the other one partial_iopf)

Yours looks better. Done.

> 
> But this looks fine either way
> 
> Reviewed-by: Jason Gunthorpe <jgg@...dia.com>

Thank you very much!

Best regards,
baolu