Re: [PATCH v3 4/5] iommufd: Add replace support in iommufd_access_set_ioas()

[Nicolin Chen]

On Thu, Mar 02, 2023 at 08:23:54AM +0000, Tian, Kevin wrote:
> External email: Use caution opening links or attachments
> 
> 
> > From: Nicolin Chen <nicolinc@xxxxxxxxxx>
> > Sent: Saturday, February 25, 2023 9:52 AM
> >
> > +     /*
> > +      * Set ioas to NULL to block any further iommufd_access_pin_pages().
> > +      * iommufd_access_unpin_pages() can continue using access-
> > >ioas_unpin.
> > +      */
> > +     access->ioas = NULL;
> > +
> > +     mutex_unlock(&access->ioas_lock);
> > +     access->ops->unmap(access->data, 0, ULONG_MAX);
> > +     mutex_lock(&access->ioas_lock);
> 
> This should check whether @unmap is valid.

Will change to 
+	if (access->ops->unmap) {
+		mutex_unlock(&access->ioas_lock);
+		access->ops->unmap(access->data, 0, ULONG_MAX);
+		mutex_lock(&access->ioas_lock);
+	}

Thanks!
Nic