[PATCH V4 02/10] iommufd: Move igroup allocation to a function

Jacob Pan
2026-04-14T21:14:16Z

From: Jason Gunthorpe <jgg@nvidia.com>

So it can be reused in the next patch which allows binding to noiommu
device.

Reviewed-by: Samiullah Khawaja <skhawaja@google.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Jacob Pan <jacob.pan@linux.microsoft.com>

---
v3:
- Moved null group check out to the next patch (Mostafa)
---
drivers/iommu/iommufd/device.c | 43 +++++++++++++++++++++-------------
1 file changed, 27 insertions(+), 16 deletions(-)

diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c
index 344d620cdecc..2f30ea069f66 100644
--- a/drivers/iommu/iommufd/device.c
+++ b/drivers/iommu/iommufd/device.c
@@ -56,6 +56,30 @@ static bool iommufd_group_try_get(struct iommufd_group *igroup,
return kref_get_unless_zero(&igroup->ref);
}

+static struct iommufd_group *iommufd_alloc_group(struct iommufd_ctx *ictx,
+ struct iommu_group *group)
+{
+ struct iommufd_group *new_igroup;
+
+ new_igroup = kzalloc(sizeof(*new_igroup), GFP_KERNEL);
+ if (!new_igroup)
+ return ERR_PTR(-ENOMEM);
+
+ kref_init(&new_igroup->ref);
+ mutex_init(&new_igroup->lock);
+ xa_init(&new_igroup->pasid_attach);
+ new_igroup->sw_msi_start = PHYS_ADDR_MAX;
+ /* group reference moves into new_igroup */
+ new_igroup->group = group;
+
+ /*
+ * The ictx is not additionally refcounted here becase all objects using
+ * an igroup must put it before their destroy completes.
+ */
+ new_igroup->ictx = ictx;
+ return new_igroup;
+}
+
/*
* iommufd needs to store some more data for each iommu_group, we keep a
* parallel xarray indexed by iommu_group id to hold this instead of putting it
@@ -87,25 +111,12 @@ static struct iommufd_group *iommufd_get_group(struct iommufd_ctx *ictx,
}
xa_unlock(&ictx->groups);

- new_igroup = kzalloc_obj(*new_igroup);
- if (!new_igroup) {
+ new_igroup = iommufd_alloc_group(ictx, group);
+ if (IS_ERR(new_igroup)) {
iommu_group_put(group);
- return ERR_PTR(-ENOMEM);
+ return new_igroup;
}

- kref_init(&new_igroup->ref);
- mutex_init(&new_igroup->lock);
- xa_init(&new_igroup->pasid_attach);
- new_igroup->sw_msi_start = PHYS_ADDR_MAX;
- /* group reference moves into new_igroup */
- new_igroup->group = group;
-
- /*
- * The ictx is not additionally refcounted here becase all objects using
- * an igroup must put it before their destroy completes.
- */
- new_igroup->ictx = ictx;
-
/*
* We dropped the lock so igroup is invalid. NULL is a safe and likely
* value to assume for the xa_cmpxchg algorithm.
--
2.34.1