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[PATCH v5 5/8] iommufd/vdevice: Remove struct device reference from struct vdevice

Xu Yilun posted 8 patches 6 months, 4 weeks ago
There is a newer version of this series
[PATCH v5 5/8] iommufd/vdevice: Remove struct device reference from struct vdevice
Posted by Xu Yilun 6 months, 4 weeks ago 
Remove struct device *dev from struct vdevice.

The dev pointer is the Plan B for vdevice to reference the physical
device. As now vdev->idev is added without refcounting concern, just
use vdev->idev->dev when needed.

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Xu Yilun <yilun.xu@linux.intel.com>
---
 drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.c | 2 +-
 drivers/iommu/iommufd/driver.c                 | 4 ++--
 drivers/iommu/iommufd/viommu.c                 | 3 ---
 include/linux/iommufd.h                        | 1 -
 4 files changed, 3 insertions(+), 7 deletions(-)

diff --git a/drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.c b/drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.c
index eb90af5093d8..8a515987b948 100644
--- a/drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.c
+++ b/drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.c
@@ -1218,7 +1218,7 @@ static void tegra241_vintf_destroy_vsid(struct iommufd_vdevice *vdev)
 
 static int tegra241_vintf_init_vsid(struct iommufd_vdevice *vdev)
 {
-	struct arm_smmu_master *master = dev_iommu_priv_get(vdev->dev);
+	struct arm_smmu_master *master = dev_iommu_priv_get(vdev->idev->dev);
 	struct tegra241_vintf *vintf = viommu_to_vintf(vdev->viommu);
 	struct tegra241_vintf_sid *vsid = vdev_to_vsid(vdev);
 	struct arm_smmu_stream *stream = &master->streams[0];
diff --git a/drivers/iommu/iommufd/driver.c b/drivers/iommu/iommufd/driver.c
index e4eae20bcd4e..df25db6d2eaf 100644
--- a/drivers/iommu/iommufd/driver.c
+++ b/drivers/iommu/iommufd/driver.c
@@ -92,7 +92,7 @@ struct device *iommufd_viommu_find_dev(struct iommufd_viommu *viommu,
 	lockdep_assert_held(&viommu->vdevs.xa_lock);
 
 	vdev = xa_load(&viommu->vdevs, vdev_id);
-	return vdev ? vdev->dev : NULL;
+	return vdev ? vdev->idev->dev : NULL;
 }
 EXPORT_SYMBOL_NS_GPL(iommufd_viommu_find_dev, "IOMMUFD");
 
@@ -109,7 +109,7 @@ int iommufd_viommu_get_vdev_id(struct iommufd_viommu *viommu,
 
 	xa_lock(&viommu->vdevs);
 	xa_for_each(&viommu->vdevs, index, vdev) {
-		if (vdev->dev == dev) {
+		if (vdev->idev->dev == dev) {
 			*vdev_id = vdev->virt_id;
 			rc = 0;
 			break;
diff --git a/drivers/iommu/iommufd/viommu.c b/drivers/iommu/iommufd/viommu.c
index ecbae5091ffe..6cf0bd5d8f08 100644
--- a/drivers/iommu/iommufd/viommu.c
+++ b/drivers/iommu/iommufd/viommu.c
@@ -125,7 +125,6 @@ void iommufd_vdevice_abort(struct iommufd_object *obj)
 	xa_cmpxchg(&viommu->vdevs, vdev->virt_id, vdev, NULL, GFP_KERNEL);
 	refcount_dec(&viommu->obj.users);
 	idev->vdev = NULL;
-	put_device(vdev->dev);
 }
 
 void iommufd_vdevice_destroy(struct iommufd_object *obj)
@@ -203,8 +202,6 @@ int iommufd_vdevice_alloc_ioctl(struct iommufd_ucmd *ucmd)
 	}
 
 	vdev->virt_id = virt_id;
-	vdev->dev = idev->dev;
-	get_device(idev->dev);
 	vdev->viommu = viommu;
 	refcount_inc(&viommu->obj.users);
 	/*
diff --git a/include/linux/iommufd.h b/include/linux/iommufd.h
index b88911026bc4..ecb0c8abd251 100644
--- a/include/linux/iommufd.h
+++ b/include/linux/iommufd.h
@@ -109,7 +109,6 @@ struct iommufd_vdevice {
 	struct iommufd_object obj;
 	struct iommufd_viommu *viommu;
 	struct iommufd_device *idev;
-	struct device *dev;
 
 	/*
 	 * Virtual device ID per vIOMMU, e.g. vSID of ARM SMMUv3, vDeviceID of
-- 
2.25.1
Re: [PATCH v5 5/8] iommufd/vdevice: Remove struct device reference from struct vdevice
Posted by kernel test robot 6 months, 4 weeks ago 
Hi Xu,

kernel test robot noticed the following build errors:

[auto build test ERROR on 601b1d0d9395c711383452bd0d47037afbbb4bcf]

url:    https://github.com/intel-lab-lkp/linux/commits/Xu-Yilun/iommufd-viommu-Roll-back-to-use-iommufd_object_alloc-for-vdevice/20250715-144326
base:   601b1d0d9395c711383452bd0d47037afbbb4bcf
patch link:    https://lore.kernel.org/r/20250715063245.1799534-6-yilun.xu%40linux.intel.com
patch subject: [PATCH v5 5/8] iommufd/vdevice: Remove struct device reference from struct vdevice
config: arm64-allmodconfig (https://download.01.org/0day-ci/archive/20250716/202507160404.4hMp40iv-lkp@intel.com/config)
compiler: clang version 19.1.7 (https://github.com/llvm/llvm-project cd708029e0b2869e80abe31ddb175f7c35361f90)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250716/202507160404.4hMp40iv-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202507160404.4hMp40iv-lkp@intel.com/

All errors (new ones prefixed by >>):

>> drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.c:1221:64: error: incomplete definition of type 'struct iommufd_device'
    1221 |         struct arm_smmu_master *master = dev_iommu_priv_get(vdev->idev->dev);
         |                                                             ~~~~~~~~~~^
   include/linux/iommufd.h:24:8: note: forward declaration of 'struct iommufd_device'
      24 | struct iommufd_device;
         |        ^
   1 error generated.


vim +1221 drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.c

  1218	
  1219	static int tegra241_vintf_init_vsid(struct iommufd_vdevice *vdev)
  1220	{
> 1221		struct arm_smmu_master *master = dev_iommu_priv_get(vdev->idev->dev);
  1222		struct tegra241_vintf *vintf = viommu_to_vintf(vdev->viommu);
  1223		struct tegra241_vintf_sid *vsid = vdev_to_vsid(vdev);
  1224		struct arm_smmu_stream *stream = &master->streams[0];
  1225		u64 virt_sid = vdev->virt_id;
  1226		int sidx;
  1227	
  1228		if (virt_sid > UINT_MAX)
  1229			return -EINVAL;
  1230	
  1231		WARN_ON_ONCE(master->num_streams != 1);
  1232	
  1233		/* Find an empty pair of SID_REPLACE and SID_MATCH */
  1234		sidx = ida_alloc_max(&vintf->sids, vintf->cmdqv->num_sids_per_vintf - 1,
  1235				     GFP_KERNEL);
  1236		if (sidx < 0)
  1237			return sidx;
  1238	
  1239		writel(stream->id, REG_VINTF(vintf, SID_REPLACE(sidx)));
  1240		writel(virt_sid << 1 | 0x1, REG_VINTF(vintf, SID_MATCH(sidx)));
  1241		dev_dbg(vintf->cmdqv->dev,
  1242			"VINTF%u: allocated SID_REPLACE%d for pSID=%x, vSID=%x\n",
  1243			vintf->idx, sidx, stream->id, (u32)virt_sid);
  1244	
  1245		vsid->idx = sidx;
  1246		vsid->vintf = vintf;
  1247		vsid->sid = stream->id;
  1248	
  1249		vdev->destroy = &tegra241_vintf_destroy_vsid;
  1250		return 0;
  1251	}
  1252	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
Re: [PATCH v5 5/8] iommufd/vdevice: Remove struct device reference from struct vdevice
Posted by Nicolin Chen 6 months, 4 weeks ago 
On Tue, Jul 15, 2025 at 02:32:42PM +0800, Xu Yilun wrote:
> diff --git a/drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.c b/drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.c
> index eb90af5093d8..8a515987b948 100644
> --- a/drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.c
> +++ b/drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.c
> @@ -1218,7 +1218,7 @@ static void tegra241_vintf_destroy_vsid(struct iommufd_vdevice *vdev)
>  
>  static int tegra241_vintf_init_vsid(struct iommufd_vdevice *vdev)
>  {
> -	struct arm_smmu_master *master = dev_iommu_priv_get(vdev->dev);
> +	struct arm_smmu_master *master = dev_iommu_priv_get(vdev->idev->dev);

Hmm, this breaks :(

drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.c: In function 'tegra241_vintf_init_vsid':
drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.c:1230:71: error: invalid use of undefined type 'struct iommufd_device'
 1230 |         struct arm_smmu_master *master = dev_iommu_priv_get(vdev->idev->dev);

Unfortunately the iommufd_device structure is defined in the
private header that's not shared with any IOMMU driver.

So, we need in the driver.c a new helper that converts a vdev
pointer to dev. Something like:

diff --git a/drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.c b/drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.c
index ff6bbd2137146..fd6b083535271 100644
--- a/drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.c
+++ b/drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.c
@@ -1227,7 +1227,8 @@ static void tegra241_vintf_destroy_vsid(struct iommufd_vdevice *vdev)
 
 static int tegra241_vintf_init_vsid(struct iommufd_vdevice *vdev)
 {
-	struct arm_smmu_master *master = dev_iommu_priv_get(vdev->idev->dev);
+	struct device *dev = iommufd_vdevice_to_device(vdev);
+	struct arm_smmu_master *master = dev_iommu_priv_get(dev);
 	struct tegra241_vintf *vintf = viommu_to_vintf(vdev->viommu);
 	struct tegra241_vintf_sid *vsid = vdev_to_vsid(vdev);
 	struct arm_smmu_stream *stream = &master->streams[0];
diff --git a/drivers/iommu/iommufd/driver.c b/drivers/iommu/iommufd/driver.c
index df25db6d2eafc..6f1010da221c9 100644
--- a/drivers/iommu/iommufd/driver.c
+++ b/drivers/iommu/iommufd/driver.c
@@ -83,6 +83,12 @@ void _iommufd_destroy_mmap(struct iommufd_ctx *ictx,
 }
 EXPORT_SYMBOL_NS_GPL(_iommufd_destroy_mmap, "IOMMUFD");
 
+struct device *iommufd_vdevice_to_device(struct iommufd_vdevice *vdev)
+{
+	return vdev->idev->dev;
+}
+EXPORT_SYMBOL_NS_GPL(iommufd_vdevice_to_device, "IOMMUFD");
+
 /* Caller should xa_lock(&viommu->vdevs) to protect the return value */
 struct device *iommufd_viommu_find_dev(struct iommufd_viommu *viommu,
 				       unsigned long vdev_id)
@@ -92,7 +98,7 @@ struct device *iommufd_viommu_find_dev(struct iommufd_viommu *viommu,
 	lockdep_assert_held(&viommu->vdevs.xa_lock);
 
 	vdev = xa_load(&viommu->vdevs, vdev_id);
-	return vdev ? vdev->idev->dev : NULL;
+	return vdev ? iommufd_vdevice_to_device(vdev) : NULL;
 }
 EXPORT_SYMBOL_NS_GPL(iommufd_viommu_find_dev, "IOMMUFD");
 
@@ -109,7 +115,7 @@ int iommufd_viommu_get_vdev_id(struct iommufd_viommu *viommu,
 
 	xa_lock(&viommu->vdevs);
 	xa_for_each(&viommu->vdevs, index, vdev) {
-		if (vdev->idev->dev == dev) {
+		if (iommufd_vdevice_to_device(vdev) == dev) {
 			*vdev_id = vdev->virt_id;
 			rc = 0;
 			break;
diff --git a/include/linux/iommufd.h b/include/linux/iommufd.h
index 61410a78cbce7..ee88e90021870 100644
--- a/include/linux/iommufd.h
+++ b/include/linux/iommufd.h
@@ -266,6 +266,7 @@ int _iommufd_alloc_mmap(struct iommufd_ctx *ictx, struct iommufd_object *owner,
 			unsigned long *offset);
 void _iommufd_destroy_mmap(struct iommufd_ctx *ictx,
 			   struct iommufd_object *owner, unsigned long offset);
+struct device *iommufd_vdevice_to_device(struct iommufd_vdevice *vdev);
 struct device *iommufd_viommu_find_dev(struct iommufd_viommu *viommu,
 				       unsigned long vdev_id);
 int iommufd_viommu_get_vdev_id(struct iommufd_viommu *viommu,
@@ -300,6 +301,12 @@ static inline void _iommufd_destroy_mmap(struct iommufd_ctx *ictx,
 {
 }
 
+static inline struct device *
+iommufd_vdevice_to_device(struct iommufd_vdevice *vdev)
+{
+	return ERR_PTR(-ENODEV);
+}
+
 static inline struct device *
 iommufd_viommu_find_dev(struct iommufd_viommu *viommu, unsigned long vdev_id)
 {
Re: [PATCH v5 5/8] iommufd/vdevice: Remove struct device reference from struct vdevice
Posted by Xu Yilun 6 months, 4 weeks ago 
On Tue, Jul 15, 2025 at 11:56:31AM -0700, Nicolin Chen wrote:
> On Tue, Jul 15, 2025 at 02:32:42PM +0800, Xu Yilun wrote:
> > diff --git a/drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.c b/drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.c
> > index eb90af5093d8..8a515987b948 100644
> > --- a/drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.c
> > +++ b/drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.c
> > @@ -1218,7 +1218,7 @@ static void tegra241_vintf_destroy_vsid(struct iommufd_vdevice *vdev)
> >  
> >  static int tegra241_vintf_init_vsid(struct iommufd_vdevice *vdev)
> >  {
> > -	struct arm_smmu_master *master = dev_iommu_priv_get(vdev->dev);
> > +	struct arm_smmu_master *master = dev_iommu_priv_get(vdev->idev->dev);
> 
> Hmm, this breaks :(
> 
> drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.c: In function 'tegra241_vintf_init_vsid':
> drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.c:1230:71: error: invalid use of undefined type 'struct iommufd_device'
>  1230 |         struct arm_smmu_master *master = dev_iommu_priv_get(vdev->idev->dev);
> 
> Unfortunately the iommufd_device structure is defined in the
> private header that's not shared with any IOMMU driver.
> 
> So, we need in the driver.c a new helper that converts a vdev
> pointer to dev. Something like:
> 
> diff --git a/drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.c b/drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.c
> index ff6bbd2137146..fd6b083535271 100644
> --- a/drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.c
> +++ b/drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.c
> @@ -1227,7 +1227,8 @@ static void tegra241_vintf_destroy_vsid(struct iommufd_vdevice *vdev)
>  
>  static int tegra241_vintf_init_vsid(struct iommufd_vdevice *vdev)
>  {
> -	struct arm_smmu_master *master = dev_iommu_priv_get(vdev->idev->dev);
> +	struct device *dev = iommufd_vdevice_to_device(vdev);
> +	struct arm_smmu_master *master = dev_iommu_priv_get(dev);
>  	struct tegra241_vintf *vintf = viommu_to_vintf(vdev->viommu);
>  	struct tegra241_vintf_sid *vsid = vdev_to_vsid(vdev);
>  	struct arm_smmu_stream *stream = &master->streams[0];
> diff --git a/drivers/iommu/iommufd/driver.c b/drivers/iommu/iommufd/driver.c
> index df25db6d2eafc..6f1010da221c9 100644
> --- a/drivers/iommu/iommufd/driver.c
> +++ b/drivers/iommu/iommufd/driver.c
> @@ -83,6 +83,12 @@ void _iommufd_destroy_mmap(struct iommufd_ctx *ictx,
>  }
>  EXPORT_SYMBOL_NS_GPL(_iommufd_destroy_mmap, "IOMMUFD");
>  
> +struct device *iommufd_vdevice_to_device(struct iommufd_vdevice *vdev)
> +{
> +	return vdev->idev->dev;
> +}
> +EXPORT_SYMBOL_NS_GPL(iommufd_vdevice_to_device, "IOMMUFD");
> +
>  /* Caller should xa_lock(&viommu->vdevs) to protect the return value */
>  struct device *iommufd_viommu_find_dev(struct iommufd_viommu *viommu,
>  				       unsigned long vdev_id)
> @@ -92,7 +98,7 @@ struct device *iommufd_viommu_find_dev(struct iommufd_viommu *viommu,
>  	lockdep_assert_held(&viommu->vdevs.xa_lock);
>  
>  	vdev = xa_load(&viommu->vdevs, vdev_id);
> -	return vdev ? vdev->idev->dev : NULL;
> +	return vdev ? iommufd_vdevice_to_device(vdev) : NULL;
>  }
>  EXPORT_SYMBOL_NS_GPL(iommufd_viommu_find_dev, "IOMMUFD");
>  
> @@ -109,7 +115,7 @@ int iommufd_viommu_get_vdev_id(struct iommufd_viommu *viommu,
>  
>  	xa_lock(&viommu->vdevs);
>  	xa_for_each(&viommu->vdevs, index, vdev) {
> -		if (vdev->idev->dev == dev) {
> +		if (iommufd_vdevice_to_device(vdev) == dev) {
>  			*vdev_id = vdev->virt_id;
>  			rc = 0;
>  			break;
> diff --git a/include/linux/iommufd.h b/include/linux/iommufd.h
> index 61410a78cbce7..ee88e90021870 100644
> --- a/include/linux/iommufd.h
> +++ b/include/linux/iommufd.h
> @@ -266,6 +266,7 @@ int _iommufd_alloc_mmap(struct iommufd_ctx *ictx, struct iommufd_object *owner,
>  			unsigned long *offset);
>  void _iommufd_destroy_mmap(struct iommufd_ctx *ictx,
>  			   struct iommufd_object *owner, unsigned long offset);
> +struct device *iommufd_vdevice_to_device(struct iommufd_vdevice *vdev);
>  struct device *iommufd_viommu_find_dev(struct iommufd_viommu *viommu,
>  				       unsigned long vdev_id);
>  int iommufd_viommu_get_vdev_id(struct iommufd_viommu *viommu,
> @@ -300,6 +301,12 @@ static inline void _iommufd_destroy_mmap(struct iommufd_ctx *ictx,
>  {
>  }
>  
> +static inline struct device *
> +iommufd_vdevice_to_device(struct iommufd_vdevice *vdev)
> +{
> +	return ERR_PTR(-ENODEV);

I prefer return NULL, which is consistent with iommufd_viommu_find_dev().

Others good to me, and thanks for your fixing.

> +}
> +
>  static inline struct device *
>  iommufd_viommu_find_dev(struct iommufd_viommu *viommu, unsigned long vdev_id)
>  {
>
Re: [PATCH v5 5/8] iommufd/vdevice: Remove struct device reference from struct vdevice
Posted by Jason Gunthorpe 6 months, 4 weeks ago 
On Tue, Jul 15, 2025 at 02:32:42PM +0800, Xu Yilun wrote:
> Remove struct device *dev from struct vdevice.
> 
> The dev pointer is the Plan B for vdevice to reference the physical
> device. As now vdev->idev is added without refcounting concern, just
> use vdev->idev->dev when needed.
> 
> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
> Reviewed-by: Kevin Tian <kevin.tian@intel.com>
> Reviewed-by: Nicolin Chen <nicolinc@nvidia.com>
> Signed-off-by: Xu Yilun <yilun.xu@linux.intel.com>
> ---
>  drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.c | 2 +-
>  drivers/iommu/iommufd/driver.c                 | 4 ++--
>  drivers/iommu/iommufd/viommu.c                 | 3 ---
>  include/linux/iommufd.h                        | 1 -
>  4 files changed, 3 insertions(+), 7 deletions(-)

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>

Jason

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