Re: [PATCH] iommu: fix return error code in iommu_probe_device()

[Will Deacon]

On Tue, Nov 17, 2020 at 07:11:28PM +0800, Yang Yingliang wrote:
> On 2020/11/17 17:40, Lu Baolu wrote:
> > On 2020/11/17 10:52, Yang Yingliang wrote:
> > > If iommu_group_get() failed, it need return error code
> > > in iommu_probe_device().
> > > 
> > > Fixes: cf193888bfbd ("iommu: Move new probe_device path...")
> > > Reported-by: Hulk Robot <hulkci@xxxxxxxxxx>
> > > Signed-off-by: Yang Yingliang <yangyingliang@xxxxxxxxxx>
> > > ---
> > >   drivers/iommu/iommu.c | 4 +++-
> > >   1 file changed, 3 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
> > > index b53446bb8c6b..6f4a32df90f6 100644
> > > --- a/drivers/iommu/iommu.c
> > > +++ b/drivers/iommu/iommu.c
> > > @@ -253,8 +253,10 @@ int iommu_probe_device(struct device *dev)
> > >           goto err_out;
> > >         group = iommu_group_get(dev);
> > > -    if (!group)
> > > +    if (!group) {
> > > +        ret = -ENODEV;
> > 
> > Can you please explain why you use -ENODEV here?
> 
> Before 79659190ee97 ("iommu: Don't take group reference in
> iommu_alloc_default_domain()"), in
> 
> iommu_alloc_default_domain(), if group is NULL, it will return -ENODEV.

Hmm. While I think the patch is ok, I'm not sure it qualifies as a fix.
Has iommu_probe_device() ever propagated this error? The commit you
identify in the 'Fixes:' tag doesn't seem to change this afaict.

Will