Re: [PATCH v2 03/10] iommu: Inline iommu_group_get_for_dev() into __iommu_probe_device()

From: Jason Gunthorpe <jgg@nvidia.com>
To: Baolu Lu <baolu.lu@linux.intel.com>
Cc: David Woodhouse <dwmw2@infradead.org>,
	iommu@lists.linux.dev, Joerg Roedel <joro@8bytes.org>,
	Len Brown <lenb@kernel.org>,
	linux-acpi@vger.kernel.org,
	"Rafael J. Wysocki" <rafael@kernel.org>,
	Robin Murphy <robin.murphy@arm.com>,
	Will Deacon <will@kernel.org>, Kevin Tian <kevin.tian@intel.com>,
	Nicolin Chen <nicolinc@nvidia.com>
Subject: Re: [PATCH v2 03/10] iommu: Inline iommu_group_get_for_dev() into __iommu_probe_device()
Date: Fri, 2 Jun 2023 14:17:54 -0300	[thread overview]
Message-ID: <ZHokQkog30XkravM@nvidia.com> (raw)
In-Reply-To: <6676d850-f633-bacd-445b-44cf045a699c@linux.intel.com>

On Sun, May 21, 2023 at 04:19:34PM +0800, Baolu Lu wrote:
> On 5/20/23 2:42 AM, Jason Gunthorpe wrote:
> > This is the only caller, and it doesn't need the generality of the
> > function. We already know there is no iommu_group, so it is simply two
> > function calls.
> > 
> > Moving it here allows the following patches to split the logic in these
> > functions.
> > 
> > Reviewed-by: Kevin Tian<kevin.tian@intel.com>
> > Signed-off-by: Jason Gunthorpe<jgg@nvidia.com>
> > ---
> >   drivers/iommu/iommu.c | 50 ++++++++-----------------------------------
> >   1 file changed, 9 insertions(+), 41 deletions(-)
> > 
> > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
> > index 35dadcc9999f8b..6177e01ced67ab 100644
> > --- a/drivers/iommu/iommu.c
> > +++ b/drivers/iommu/iommu.c
> > @@ -127,7 +127,6 @@ static int iommu_setup_default_domain(struct iommu_group *group,
> >   				      int target_type);
> >   static int iommu_create_device_direct_mappings(struct iommu_domain *domain,
> >   					       struct device *dev);
> > -static struct iommu_group *iommu_group_get_for_dev(struct device *dev);
> >   static ssize_t iommu_group_store_type(struct iommu_group *group,
> >   				      const char *buf, size_t count);
> > @@ -379,12 +378,18 @@ static int __iommu_probe_device(struct device *dev, struct list_head *group_list
> >   	if (ops->is_attach_deferred)
> >   		dev->iommu->attach_deferred = ops->is_attach_deferred(dev);
> > -	group = iommu_group_get_for_dev(dev);
> > +	group = ops->device_group(dev);
> > +	if (WARN_ON_ONCE(group == NULL))
> > +		group = ERR_PTR(-EINVAL);
> >   	if (IS_ERR(group)) {
> >   		ret = PTR_ERR(group);
> >   		goto out_release;
> >   	}
> > +	ret = iommu_group_add_device(group, dev);
> > +	if (ret)
> > +		goto err_put_group;
> > +
> >   	mutex_lock(&group->mutex);
> >   	if (group_list && !group->default_domain && list_empty(&group->entry))
> >   		list_add_tail(&group->entry, group_list);
> > @@ -396,6 +401,8 @@ static int __iommu_probe_device(struct device *dev, struct list_head *group_list
> >   	return 0;
> > +err_put_group:
> 
> nit: perhaps out_put_group?

err_ is the right label, this is not a success path.. Most of the
labels are err_ except for out_unlock which is sometimes a success and
out_module_put which has always been mislabeled..

Jason