Re: [PATCH v9 04/11] iommu: Add sva iommu_domain support

[Baolu Lu]

On 2022/6/28 16:50, Tian, Kevin wrote:
> > > > +
> > > > +	mutex_lock(&group->mutex);
> > > > +	curr = xa_cmpxchg(&group->pasid_array, pasid, NULL, domain,
> > > > GFP_KERNEL);
> > > > +	if (curr)
> > > > +		goto out_unlock;
> > > Need check xa_is_err(old).
> > Either
> >
> > (1) old entry is a valid pointer, or
> return -EBUSY in this case
>
> > (2) xa_is_err(curr)
> return xa_err(cur)
>
> > are failure cases. Hence, "curr == NULL" is the only check we need. Did
> > I miss anything?
> But now you always return -EBUSY for all kinds of xa errors.

Fair enough. Updated like below.

        curr = xa_cmpxchg(&group->pasid_array, pasid, NULL, domain, 
GFP_KERNEL);
        if (curr) {
                ret = xa_err(curr) ? : -EBUSY;
                goto out_unlock;
        }

Best regards,
baolu