[PATCH 02/11] iommufd: Move igroup allocation to a function

[Jacob Pan <jacob.pan@linux.microsoft.com>]

From: Jason Gunthorpe <jgg@nvidia.com>

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

Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Jacob Pan <jacob.pan@linux.microsoft.com>
---
 drivers/iommu/iommufd/device.c | 48 +++++++++++++++++++++-------------
 1 file changed, 30 insertions(+), 18 deletions(-)

diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c
index 344d620cdecc..54d73016468f 100644
--- a/drivers/iommu/iommufd/device.c
+++ b/drivers/iommu/iommufd/device.c
@@ -30,8 +30,9 @@ static void iommufd_group_release(struct kref *kref)
 
 	WARN_ON(!xa_empty(&igroup->pasid_attach));
 
-	xa_cmpxchg(&igroup->ictx->groups, iommu_group_id(igroup->group), igroup,
-		   NULL, GFP_KERNEL);
+	if (igroup->group)
+		xa_cmpxchg(&igroup->ictx->groups, iommu_group_id(igroup->group),
+			   igroup, NULL, GFP_KERNEL);
 	iommu_group_put(igroup->group);
 	mutex_destroy(&igroup->lock);
 	kfree(igroup);
@@ -56,6 +57,30 @@ 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 +112,12 @@ 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