[PATCH v2 5/9] vfio/mdev: Consolidate all the device_api sysfs into the core code

[Jason Gunthorpe <jgg@nvidia.com>]

Every driver just emits a static string, simply feed it through the ops
and provide a standard sysfs show function.

Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
---
 drivers/gpu/drm/i915/gvt/kvmgt.c  |  9 +--------
 drivers/s390/cio/vfio_ccw_ops.c   |  9 +--------
 drivers/s390/crypto/vfio_ap_ops.c |  9 +--------
 drivers/vfio/mdev/mdev_core.c     |  2 +-
 drivers/vfio/mdev/mdev_sysfs.c    | 27 ++++++++++++++++++++++++---
 include/linux/mdev.h              |  7 ++-----
 samples/vfio-mdev/mbochs.c        |  9 +--------
 samples/vfio-mdev/mdpy.c          |  9 +--------
 samples/vfio-mdev/mtty.c          | 10 +---------
 9 files changed, 33 insertions(+), 58 deletions(-)

diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
index 7efa386449d104..d198cc3d132277 100644
--- a/drivers/gpu/drm/i915/gvt/kvmgt.c
+++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
@@ -161,12 +161,6 @@ static ssize_t available_instances_show(struct mdev_type *mtype,
 	return sprintf(buf, "%u\n", num);
 }
 
-static ssize_t device_api_show(struct mdev_type *mtype,
-			       struct mdev_type_attribute *attr, char *buf)
-{
-	return sprintf(buf, "%s\n", VFIO_DEVICE_API_PCI_STRING);
-}
-
 static ssize_t description_show(struct mdev_type *mtype,
 				struct mdev_type_attribute *attr, char *buf)
 {
@@ -187,12 +181,10 @@ static ssize_t description_show(struct mdev_type *mtype,
 }
 
 static MDEV_TYPE_ATTR_RO(available_instances);
-static MDEV_TYPE_ATTR_RO(device_api);
 static MDEV_TYPE_ATTR_RO(description);
 
 static struct attribute *gvt_type_attrs[] = {
 	&mdev_type_attr_available_instances.attr,
-	&mdev_type_attr_device_api.attr,
 	&mdev_type_attr_description.attr,
 	NULL,
 };
@@ -1750,6 +1742,7 @@ static const struct attribute_group *intel_vgpu_groups[] = {
 
 static struct mdev_parent_ops intel_vgpu_ops = {
 	.mdev_attr_groups       = intel_vgpu_groups,
+	.device_api		= VFIO_DEVICE_API_PCI_STRING,
 	.create			= intel_vgpu_create,
 	.remove			= intel_vgpu_remove,
 
diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
index 6e70620d5dfbc8..18a48d1f1e8fff 100644
--- a/drivers/s390/cio/vfio_ccw_ops.c
+++ b/drivers/s390/cio/vfio_ccw_ops.c
@@ -70,13 +70,6 @@ static ssize_t name_show(struct mdev_type *mtype,
 }
 static MDEV_TYPE_ATTR_RO(name);
 
-static ssize_t device_api_show(struct mdev_type *mtype,
-			       struct mdev_type_attribute *attr, char *buf)
-{
-	return sprintf(buf, "%s\n", VFIO_DEVICE_API_CCW_STRING);
-}
-static MDEV_TYPE_ATTR_RO(device_api);
-
 static ssize_t available_instances_show(struct mdev_type *mtype,
 					struct mdev_type_attribute *attr,
 					char *buf)
@@ -90,7 +83,6 @@ static MDEV_TYPE_ATTR_RO(available_instances);
 
 static struct attribute *mdev_types_attrs[] = {
 	&mdev_type_attr_name.attr,
-	&mdev_type_attr_device_api.attr,
 	&mdev_type_attr_available_instances.attr,
 	NULL,
 };
@@ -640,6 +632,7 @@ struct mdev_driver vfio_ccw_mdev_driver = {
 static const struct mdev_parent_ops vfio_ccw_mdev_ops = {
 	.owner			= THIS_MODULE,
 	.device_driver		= &vfio_ccw_mdev_driver,
+	.device_api		= VFIO_DEVICE_API_CCW_STRING,
 	.supported_type_groups  = mdev_type_groups,
 };
 
diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index 54bb0c22e8020e..005c2a2b14af3f 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -400,17 +400,9 @@ static ssize_t available_instances_show(struct mdev_type *mtype,
 
 static MDEV_TYPE_ATTR_RO(available_instances);
 
-static ssize_t device_api_show(struct mdev_type *mtype,
-			       struct mdev_type_attribute *attr, char *buf)
-{
-	return sprintf(buf, "%s\n", VFIO_DEVICE_API_AP_STRING);
-}
-
-static MDEV_TYPE_ATTR_RO(device_api);
 
 static struct attribute *vfio_ap_mdev_type_attrs[] = {
 	&mdev_type_attr_name.attr,
-	&mdev_type_attr_device_api.attr,
 	&mdev_type_attr_available_instances.attr,
 	NULL,
 };
@@ -1399,6 +1391,7 @@ static struct mdev_driver vfio_ap_matrix_driver = {
 static const struct mdev_parent_ops vfio_ap_matrix_ops = {
 	.owner			= THIS_MODULE,
 	.device_driver		= &vfio_ap_matrix_driver,
+	.device_api		= VFIO_DEVICE_API_AP_STRING,
 	.supported_type_groups	= vfio_ap_mdev_type_groups,
 };
 
diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c
index b314101237fe22..c3018e8e6d3258 100644
--- a/drivers/vfio/mdev/mdev_core.c
+++ b/drivers/vfio/mdev/mdev_core.c
@@ -129,7 +129,7 @@ int mdev_register_device(struct device *dev, const struct mdev_parent_ops *ops)
 	char *envp[] = { env_string, NULL };
 
 	/* check for mandatory ops */
-	if (!ops || !ops->supported_type_groups)
+	if (!ops || !ops->supported_type_groups || !ops->device_api)
 		return -EINVAL;
 	if (!ops->device_driver && (!ops->create || !ops->remove))
 		return -EINVAL;
diff --git a/drivers/vfio/mdev/mdev_sysfs.c b/drivers/vfio/mdev/mdev_sysfs.c
index f5cf1931c54e48..d4b99440d19e9a 100644
--- a/drivers/vfio/mdev/mdev_sysfs.c
+++ b/drivers/vfio/mdev/mdev_sysfs.c
@@ -74,9 +74,30 @@ static ssize_t create_store(struct mdev_type *mtype,
 
 	return count;
 }
-
 static MDEV_TYPE_ATTR_WO(create);
 
+static ssize_t device_api_show(struct mdev_type *mtype,
+			       struct mdev_type_attribute *attr, char *buf)
+{
+	return sysfs_emit(buf, "%s\n", mtype->parent->ops->device_api);
+}
+static MDEV_TYPE_ATTR_RO(device_api);
+
+static struct attribute *mdev_types_std_attrs[] = {
+	&mdev_type_attr_create.attr,
+	&mdev_type_attr_device_api.attr,
+	NULL,
+};
+
+static struct attribute_group mdev_type_std_group = {
+	.attrs = mdev_types_std_attrs,
+};
+
+static const struct attribute_group *mdev_type_groups[] = {
+	&mdev_type_std_group,
+	NULL,
+};
+
 static void mdev_type_release(struct kobject *kobj)
 {
 	struct mdev_type *type = to_mdev_type(kobj);
@@ -123,7 +144,7 @@ static struct mdev_type *add_mdev_supported_type(struct mdev_parent *parent,
 		return ERR_PTR(ret);
 	}
 
-	ret = sysfs_create_file(&type->kobj, &mdev_type_attr_create.attr);
+	ret = sysfs_create_groups(&type->kobj, mdev_type_groups);
 	if (ret)
 		goto attr_create_failed;
 
@@ -144,7 +165,7 @@ static struct mdev_type *add_mdev_supported_type(struct mdev_parent *parent,
 attrs_failed:
 	kobject_put(type->devices_kobj);
 attr_devices_failed:
-	sysfs_remove_file(&type->kobj, &mdev_type_attr_create.attr);
+	sysfs_remove_groups(&type->kobj, mdev_type_groups);
 attr_create_failed:
 	kobject_del(&type->kobj);
 	kobject_put(&type->kobj);
diff --git a/include/linux/mdev.h b/include/linux/mdev.h
index 68427e8fadebd6..7f1db354f45f14 100644
--- a/include/linux/mdev.h
+++ b/include/linux/mdev.h
@@ -56,6 +56,7 @@ struct device *mtype_get_parent_dev(struct mdev_type *mtype);
  *
  * @owner:		The module owner.
  * @device_driver:	Which device driver to probe() on newly created devices
+ * @device_api:		String to return for the device_api sysfs
  * @dev_attr_groups:	Attributes of the parent device.
  * @mdev_attr_groups:	Attributes of the mediated device.
  * @supported_type_groups: Attributes to define supported types. It is mandatory
@@ -100,6 +101,7 @@ struct device *mtype_get_parent_dev(struct mdev_type *mtype);
 struct mdev_parent_ops {
 	struct module   *owner;
 	struct mdev_driver *device_driver;
+	const char *device_api;
 	const struct attribute_group **dev_attr_groups;
 	const struct attribute_group **mdev_attr_groups;
 	struct attribute_group **supported_type_groups;
@@ -128,11 +130,6 @@ struct mdev_type_attribute {
 			 size_t count);
 };
 
-#define MDEV_TYPE_ATTR(_name, _mode, _show, _store)		\
-struct mdev_type_attribute mdev_type_attr_##_name =		\
-	__ATTR(_name, _mode, _show, _store)
-#define MDEV_TYPE_ATTR_RW(_name) \
-	struct mdev_type_attribute mdev_type_attr_##_name = __ATTR_RW(_name)
 #define MDEV_TYPE_ATTR_RO(_name) \
 	struct mdev_type_attribute mdev_type_attr_##_name = __ATTR_RO(_name)
 #define MDEV_TYPE_ATTR_WO(_name) \
diff --git a/samples/vfio-mdev/mbochs.c b/samples/vfio-mdev/mbochs.c
index c313ab4d1f4e4e..abd889bc1f9dcf 100644
--- a/samples/vfio-mdev/mbochs.c
+++ b/samples/vfio-mdev/mbochs.c
@@ -1358,17 +1358,9 @@ static ssize_t available_instances_show(struct mdev_type *mtype,
 }
 static MDEV_TYPE_ATTR_RO(available_instances);
 
-static ssize_t device_api_show(struct mdev_type *mtype,
-			       struct mdev_type_attribute *attr, char *buf)
-{
-	return sprintf(buf, "%s\n", VFIO_DEVICE_API_PCI_STRING);
-}
-static MDEV_TYPE_ATTR_RO(device_api);
-
 static struct attribute *mdev_types_attrs[] = {
 	&mdev_type_attr_name.attr,
 	&mdev_type_attr_description.attr,
-	&mdev_type_attr_device_api.attr,
 	&mdev_type_attr_available_instances.attr,
 	NULL,
 };
@@ -1417,6 +1409,7 @@ static struct mdev_driver mbochs_driver = {
 static const struct mdev_parent_ops mdev_fops = {
 	.owner			= THIS_MODULE,
 	.device_driver		= &mbochs_driver,
+	.device_api		= VFIO_DEVICE_API_PCI_STRING,
 	.supported_type_groups	= mdev_type_groups,
 };
 
diff --git a/samples/vfio-mdev/mdpy.c b/samples/vfio-mdev/mdpy.c
index 8d1a80a0722aa9..b81d7848619cae 100644
--- a/samples/vfio-mdev/mdpy.c
+++ b/samples/vfio-mdev/mdpy.c
@@ -670,17 +670,9 @@ static ssize_t available_instances_show(struct mdev_type *mtype,
 }
 static MDEV_TYPE_ATTR_RO(available_instances);
 
-static ssize_t device_api_show(struct mdev_type *mtype,
-			       struct mdev_type_attribute *attr, char *buf)
-{
-	return sprintf(buf, "%s\n", VFIO_DEVICE_API_PCI_STRING);
-}
-static MDEV_TYPE_ATTR_RO(device_api);
-
 static struct attribute *mdev_types_attrs[] = {
 	&mdev_type_attr_name.attr,
 	&mdev_type_attr_description.attr,
-	&mdev_type_attr_device_api.attr,
 	&mdev_type_attr_available_instances.attr,
 	NULL,
 };
@@ -728,6 +720,7 @@ static struct mdev_driver mdpy_driver = {
 static const struct mdev_parent_ops mdev_fops = {
 	.owner			= THIS_MODULE,
 	.device_driver          = &mdpy_driver,
+	.device_api		= VFIO_DEVICE_API_PCI_STRING,
 	.supported_type_groups	= mdev_type_groups,
 };
 
diff --git a/samples/vfio-mdev/mtty.c b/samples/vfio-mdev/mtty.c
index 5983cdb16e3d1d..b473ecc7733f7d 100644
--- a/samples/vfio-mdev/mtty.c
+++ b/samples/vfio-mdev/mtty.c
@@ -1281,17 +1281,8 @@ static ssize_t available_instances_show(struct mdev_type *mtype,
 
 static MDEV_TYPE_ATTR_RO(available_instances);
 
-static ssize_t device_api_show(struct mdev_type *mtype,
-			       struct mdev_type_attribute *attr, char *buf)
-{
-	return sprintf(buf, "%s\n", VFIO_DEVICE_API_PCI_STRING);
-}
-
-static MDEV_TYPE_ATTR_RO(device_api);
-
 static struct attribute *mdev_types_attrs[] = {
 	&mdev_type_attr_name.attr,
-	&mdev_type_attr_device_api.attr,
 	&mdev_type_attr_available_instances.attr,
 	NULL,
 };
@@ -1333,6 +1324,7 @@ static struct mdev_driver mtty_driver = {
 static const struct mdev_parent_ops mdev_fops = {
 	.owner                  = THIS_MODULE,
 	.device_driver		= &mtty_driver,
+	.device_api		= VFIO_DEVICE_API_PCI_STRING,
 	.dev_attr_groups        = mtty_dev_groups,
 	.supported_type_groups  = mdev_type_groups,
 };
-- 
2.33.0