Hi Kevin, On Tue, 11 Apr 2023 08:02:55 +0000, "Tian, Kevin" <kevin.tian@xxxxxxxxx> wrote: > > From: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx> > > Sent: Saturday, April 8, 2023 2:06 AM > > @@ -28,8 +26,8 @@ static int iommu_sva_alloc_pasid(struct mm_struct > > *mm, ioasid_t min, ioasid_t ma > > goto out; > > } > > > > - ret = ida_alloc_range(&iommu_global_pasid_ida, min, max, > > GFP_KERNEL); > > - if (ret < min) > > + ret = iommu_alloc_global_pasid(min, max); > > I wonder whether this can take a device pointer so dev->iommu->max_pasids > is enforced inside the alloc function. > > and do we even need the min/max parameters? With special pasids reserved > then what driver needs is just to get a free pasid from the global space > within dev->iommu->max_pasids constraint... > > iommu_sva_alloc_pasid() can be reworked to avoid min/max by taking a > device pointer too. I think that will work too albeit a philosophical change. It probably should be called iommu_alloc_dev_global_pasid(dev). But I feel the current approach is more flexible in that device drivers can control the range if for some reason it does not want go max_pasid. Thanks, Jacob
