Re: [PATCH 07/12] iommu/vt-d: Acquiring lock in pasid manipulation helpers

Baolu Lu
2022-06-01T10:48:35Z

On 2022/6/1 17:18, Tian, Kevin wrote:
>> From: Lu Baolu <baolu.lu@linux.intel.com>
>> Sent: Friday, May 27, 2022 2:30 PM
>>
>> The iommu->lock is used to protect the per-IOMMU pasid directory table
>> and pasid table. Move the spinlock acquisition/release into the helpers
>> to make the code self-contained.
>>
>> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
>
> Reviewed-by: Kevin Tian <kevin.tian@intel.com>, with one nit
>
>>
>> - /* Caller must ensure PASID entry is not in use. */
>> - if (pasid_pte_is_present(pte))
>> - return -EBUSY;
>> + spin_lock(&iommu->lock);
>> + pte = get_non_present_pasid_entry(dev, pasid);
>> + if (!pte) {
>> + spin_unlock(&iommu->lock);
>> + return -ENODEV;
>> + }
>
> I don't think above is a good abstraction and it changes the error
> code for an present entry from -EBUSY to -ENODEV.

Sure. I will roll it back to -EBUSY. I added this helper because the
same code appears at least three times in this file.

Best regards,
baolu