Messages in this thread | | | From | Thomas Gleixner <> | Subject | Re: [PATCH v2 05/11] iommu/sva: Assign a PASID to mm on PASID allocation and free it on mm exit | Date | Mon, 24 Jan 2022 21:21:24 +0100 |
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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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