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

Tian, Kevin
2022-06-01T09:18:23Z

> 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.