Re: [PATCH v2 05/12] iommu: Change the return value of dev_iommu_get()

[Baolu Lu]

On 8/4/23 11:55 AM, Tian, Kevin wrote:
> > From: Baolu Lu<baolu.lu@xxxxxxxxxxxxxxx>
> > Sent: Friday, August 4, 2023 11:10 AM
> >
> > On 2023/8/3 15:59, Tian, Kevin wrote:
> > > > From: Lu Baolu<baolu.lu@xxxxxxxxxxxxxxx>
> > > > Sent: Thursday, July 27, 2023 1:49 PM
> > > >
> > > > Make dev_iommu_get() return 0 for success and error numbers for failure.
> > > > This will make the code neat and readable. No functionality changes.
> > > >
> > > > Reviewed-by: Jacob Pan<jacob.jun.pan@xxxxxxxxxxxxxxx>
> > > > Signed-off-by: Lu Baolu<baolu.lu@xxxxxxxxxxxxxxx>
> > > > ---
> > > >    drivers/iommu/iommu.c | 19 +++++++++++--------
> > > >    1 file changed, 11 insertions(+), 8 deletions(-)
> > > >
> > > > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
> > > > index 00309f66153b..4ba3bb692993 100644
> > > > --- a/drivers/iommu/iommu.c
> > > > +++ b/drivers/iommu/iommu.c
> > > > @@ -290,20 +290,20 @@ void iommu_device_unregister(struct
> > > > iommu_device *iommu)
> > > >    }
> > > >    EXPORT_SYMBOL_GPL(iommu_device_unregister);
> > > >
> > > > -static struct dev_iommu *dev_iommu_get(struct device *dev)
> > > > +static int dev_iommu_get(struct device *dev)
> > > >    {
> > > >    	struct dev_iommu *param = dev->iommu;
> > > >
> > > >    	if (param)
> > > > -		return param;
> > > > +		return 0;
> > > >
> > > >    	param = kzalloc(sizeof(*param), GFP_KERNEL);
> > > >    	if (!param)
> > > > -		return NULL;
> > > > +		return -ENOMEM;
> > > >
> > > >    	mutex_init(&param->lock);
> > > >    	dev->iommu = param;
> > > > -	return param;
> > > > +	return 0;
> > > >    }
> > > Jason's series [1] has been queued. Time to refine according to
> > > the discussion in [2].
> > >
> > > [1]https://lore.kernel.org/linux-iommu/ZLFYXlSBZrlxFpHM@xxxxxxxxxx/
> > > [2]https://lore.kernel.org/linux-iommu/c815fa2b-00df-91e1-8353-
> > 8258773957e4@xxxxxxxxxxxxxxx/
> >
> > I'm not sure I understand your point here. This only changes the return
> > value of dev_iommu_get() to make the code more concise.
> I thought the purpose of this patch was to prepare for next patch which
> moves dev->fault_param initialization to dev_iommu_get().

Yes.

> with Jason's rework IMHO that initialization more fits in iommu_init_device().
>
> that's my real point. If you still want to clean up dev_iommu_get() it's fine
> but then it may not belong to this series. 😊

Ah, I see. Let me make a choice in the next version.

Best regards,
baolu