On Fri, Dec 17 2021 at 22:01, Fenghua Yu wrote:
> diff --git a/drivers/iommu/iommu-sva-lib.c b/drivers/iommu/iommu-sva-lib.c
> index bd41405d34e9..ee2294e02716 100644
> --- a/drivers/iommu/iommu-sva-lib.c
> +++ b/drivers/iommu/iommu-sva-lib.c
> @@ -18,8 +18,7 @@ static DECLARE_IOASID_SET(iommu_sva_pasid);
> *
> * Try to allocate a PASID for this mm, or take a reference to the existing
> one
> * provided it fits within the [@min, @max] range. On success the PASID is
> - * available in mm->pasid, and must be released with iommu_sva_free_pasid().
> - * @min must be greater than 0, because 0 indicates an unused mm->pasid.
> + * available in mm->pasid and will be available for the lifetime of the mm.
> *
> * Returns 0 on success and < 0 on error.
> */
> @@ -33,38 +32,24 @@ int iommu_sva_alloc_pasid(struct mm_struct *mm, ioasid_t
> min, ioasid_t max)
> return -EINVAL;
>
> mutex_lock(&iommu_sva_lock);
> - if (mm->pasid) {
> - if (mm->pasid >= min && mm->pasid <= max)
> - ioasid_get(mm->pasid);
> - else
> + /* Is a PASID already associated with this mm? */
> + if (pasid_valid(mm->pasid)) {
> + if (mm->pasid < min || mm->pasid >= max)
> ret = -EOVERFLOW;
> - } else {
> - pasid = ioasid_alloc(&iommu_sva_pasid, min, max, mm);
> - if (pasid == INVALID_IOASID)
> - ret = -ENOMEM;
> - else
> - mm->pasid = pasid;
> + goto out;
> }
> +
> + pasid = ioasid_alloc(&iommu_sva_pasid, min, max, mm);
> + if (!pasid_valid(pasid))
> + ret = -ENOMEM;
> + else
> + mm_pasid_get(mm, pasid);
Hrm. This is odd.
> +/* Associate a PASID with an mm_struct: */
> +static inline void mm_pasid_get(struct mm_struct *mm, u32 pasid)
> +{
> + mm->pasid = pasid;
> +}
This does not get anything. It sets the allocated PASID in the mm. The
refcount on the PASID was already taken by the allocation. So this
should be mm_pasid_set() or mm_pasid_install(), right?
Thanks,
tglx
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