[RFC 2/8] iommufd: replace attach_fn with a structure

[Yi Liu]

Most of the core logic before conducting the actual device attach/
replace operation can be shared with pasid attach/replace. Create
a new structure so more information (e.g. pasid) can be later added
along with the attach_fn.

Signed-off-by: Kevin Tian <kevin.tian@xxxxxxxxx>
Signed-off-by: Yi Liu <yi.l.liu@xxxxxxxxx>
---
 drivers/iommu/iommufd/device.c          | 35 ++++++++++++++++---------
 drivers/iommu/iommufd/iommufd_private.h |  8 ++++++
 2 files changed, 30 insertions(+), 13 deletions(-)

diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c
index 645ab5d290fe..4fa4153c5df7 100644
--- a/drivers/iommu/iommufd/device.c
+++ b/drivers/iommu/iommufd/device.c
@@ -597,8 +597,11 @@ iommufd_device_do_replace(struct iommufd_device *idev,
 	return ERR_PTR(rc);
 }
 
-typedef struct iommufd_hw_pagetable *(*attach_fn)(
-	struct iommufd_device *idev, struct iommufd_hw_pagetable *hwpt);
+static struct iommufd_hw_pagetable *do_attach(struct iommufd_device *idev,
+		struct iommufd_hw_pagetable *hwpt, struct attach_data *data)
+{
+	return data->attach_fn(idev, hwpt);
+}
 
 /*
  * When automatically managing the domains we search for a compatible domain in
@@ -608,7 +611,7 @@ typedef struct iommufd_hw_pagetable *(*attach_fn)(
 static struct iommufd_hw_pagetable *
 iommufd_device_auto_get_domain(struct iommufd_device *idev,
 			       struct iommufd_ioas *ioas, u32 *pt_id,
-			       attach_fn do_attach)
+			       struct attach_data *data)
 {
 	/*
 	 * iommufd_hw_pagetable_attach() is called by
@@ -617,7 +620,7 @@ iommufd_device_auto_get_domain(struct iommufd_device *idev,
 	 * to use the immediate_attach path as it supports drivers that can't
 	 * directly allocate a domain.
 	 */
-	bool immediate_attach = do_attach == iommufd_device_do_attach;
+	bool immediate_attach = data->attach_fn == iommufd_device_do_attach;
 	struct iommufd_hw_pagetable *destroy_hwpt;
 	struct iommufd_hw_pagetable *hwpt;
 
@@ -633,7 +636,7 @@ iommufd_device_auto_get_domain(struct iommufd_device *idev,
 
 		if (!iommufd_lock_obj(&hwpt->obj))
 			continue;
-		destroy_hwpt = (*do_attach)(idev, hwpt);
+		destroy_hwpt = do_attach(idev, hwpt, data);
 		if (IS_ERR(destroy_hwpt)) {
 			iommufd_put_object(&hwpt->obj);
 			/*
@@ -660,7 +663,7 @@ iommufd_device_auto_get_domain(struct iommufd_device *idev,
 	}
 
 	if (!immediate_attach) {
-		destroy_hwpt = (*do_attach)(idev, hwpt);
+		destroy_hwpt = do_attach(idev, hwpt, data);
 		if (IS_ERR(destroy_hwpt))
 			goto out_abort;
 	} else {
@@ -681,8 +684,8 @@ iommufd_device_auto_get_domain(struct iommufd_device *idev,
 	return destroy_hwpt;
 }
 
-static int iommufd_device_change_pt(struct iommufd_device *idev, u32 *pt_id,
-				    attach_fn do_attach)
+int iommufd_device_change_pt(struct iommufd_device *idev, u32 *pt_id,
+			     struct attach_data *data)
 {
 	struct iommufd_hw_pagetable *destroy_hwpt;
 	struct iommufd_object *pt_obj;
@@ -696,7 +699,7 @@ static int iommufd_device_change_pt(struct iommufd_device *idev, u32 *pt_id,
 		struct iommufd_hw_pagetable *hwpt =
 			container_of(pt_obj, struct iommufd_hw_pagetable, obj);
 
-		destroy_hwpt = (*do_attach)(idev, hwpt);
+		destroy_hwpt = do_attach(idev, hwpt, data);
 		if (IS_ERR(destroy_hwpt))
 			goto out_put_pt_obj;
 		break;
@@ -706,7 +709,7 @@ static int iommufd_device_change_pt(struct iommufd_device *idev, u32 *pt_id,
 			container_of(pt_obj, struct iommufd_ioas, obj);
 
 		destroy_hwpt = iommufd_device_auto_get_domain(idev, ioas, pt_id,
-							      do_attach);
+							      data);
 		if (IS_ERR(destroy_hwpt))
 			goto out_put_pt_obj;
 		break;
@@ -742,8 +745,11 @@ static int iommufd_device_change_pt(struct iommufd_device *idev, u32 *pt_id,
 int iommufd_device_attach(struct iommufd_device *idev, u32 *pt_id)
 {
 	int rc;
+	struct attach_data data = {
+		.attach_fn = &iommufd_device_do_attach,
+	};
 
-	rc = iommufd_device_change_pt(idev, pt_id, &iommufd_device_do_attach);
+	rc = iommufd_device_change_pt(idev, pt_id, &data);
 	if (rc)
 		return rc;
 
@@ -773,8 +779,11 @@ EXPORT_SYMBOL_NS_GPL(iommufd_device_attach, IOMMUFD);
  */
 int iommufd_device_replace(struct iommufd_device *idev, u32 *pt_id)
 {
-	return iommufd_device_change_pt(idev, pt_id,
-					&iommufd_device_do_replace);
+	struct attach_data data = {
+		.attach_fn = &iommufd_device_do_replace,
+	};
+
+	return iommufd_device_change_pt(idev, pt_id, &data);
 }
 EXPORT_SYMBOL_NS_GPL(iommufd_device_replace, IOMMUFD);
 
diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h
index 1bd412cff2d6..f1fe4120c3b1 100644
--- a/drivers/iommu/iommufd/iommufd_private.h
+++ b/drivers/iommu/iommufd/iommufd_private.h
@@ -353,6 +353,14 @@ int iommufd_get_hw_info(struct iommufd_ucmd *ucmd);
 int iommufd_set_dev_data(struct iommufd_ucmd *ucmd);
 int iommufd_unset_dev_data(struct iommufd_ucmd *ucmd);
 
+struct attach_data {
+	union {
+		struct iommufd_hw_pagetable *(*attach_fn)(
+				struct iommufd_device *idev,
+				struct iommufd_hw_pagetable *hwpt);
+	};
+};
+
 struct iommufd_access {
 	struct iommufd_object obj;
 	struct iommufd_ctx *ictx;
-- 
2.34.1