Re: [PATCH 09/13] vfio/mdev: consolidate all the device_api sysfs into the core code

Kirti Wankhede <kwankhede@xxxxxxxxxx> · Thu, 16 Jun 2022 01:54:22 +0530

On 6/14/2022 10:24 AM, Christoph Hellwig wrote:
From: Jason Gunthorpe <jgg@xxxxxxxxxx>

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@xxxxxxxxxx>
Signed-off-by: Christoph Hellwig <hch@xxxxxx>

Reviewed-by: Kirti Wankhede <kwankhede@xxxxxxxxxx>

---
  .../driver-api/vfio-mediated-device.rst       |  2 +-
  drivers/gpu/drm/i915/gvt/kvmgt.c              |  9 +----
  drivers/s390/cio/vfio_ccw_ops.c               | 11 ++----
  drivers/s390/crypto/vfio_ap_ops.c             | 10 +-----
  drivers/vfio/mdev/mdev_driver.c               |  4 ++-
  drivers/vfio/mdev/mdev_sysfs.c                | 35 +++++++++++++------
  include/linux/mdev.h                          |  7 ++--
  samples/vfio-mdev/mbochs.c                    |  9 +----
  samples/vfio-mdev/mdpy.c                      |  9 +----
  samples/vfio-mdev/mtty.c                      | 10 +-----
  10 files changed, 38 insertions(+), 68 deletions(-)

diff --git a/Documentation/driver-api/vfio-mediated-device.rst b/Documentation/driver-api/vfio-mediated-device.rst
index 27247b3bdcb57..e9913bfb4393b 100644
--- a/Documentation/driver-api/vfio-mediated-device.rst
+++ b/Documentation/driver-api/vfio-mediated-device.rst
@@ -204,7 +204,7 @@ Directories and files under the sysfs for Each Physical Device
  
  * device_api
  
-  This attribute should show which device API is being created, for example,
+  This attribute shows which device API is being created, for example,
    "vfio-pci" for a PCI device.
  
  * available_instances
diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
index 136f9c0df48b9..44a418d897377 100644
--- a/drivers/gpu/drm/i915/gvt/kvmgt.c
+++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
@@ -123,12 +123,6 @@ static ssize_t available_instances_show(struct mdev_type *mtype,
  	return sprintf(buf, "%u\n", type->avail_instance);
  }
  
-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)
  {
@@ -151,13 +145,11 @@ static ssize_t name_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 MDEV_TYPE_ATTR_RO(name);
  
  static const struct attribute *gvt_type_attrs[] = {
  	&mdev_type_attr_available_instances.attr,
-	&mdev_type_attr_device_api.attr,
  	&mdev_type_attr_description.attr,
  	&mdev_type_attr_name.attr,
  	NULL,
@@ -1587,6 +1579,7 @@ static void intel_vgpu_remove(struct mdev_device *mdev)
  }
  
  static struct mdev_driver intel_vgpu_mdev_driver = {
+	.device_api	= VFIO_DEVICE_API_PCI_STRING,
  	.driver = {
  		.name		= "intel_vgpu_mdev",
  		.owner		= THIS_MODULE,
diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
index 43d53736dfe3c..730d87a96a305 100644
--- a/drivers/s390/cio/vfio_ccw_ops.c
+++ b/drivers/s390/cio/vfio_ccw_ops.c
@@ -77,13 +77,6 @@ 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)
@@ -96,7 +89,6 @@ static MDEV_TYPE_ATTR_RO(available_instances);
  
  static const struct attribute *mdev_types_attrs[] = {
  	&mdev_type_attr_name.attr,
-	&mdev_type_attr_device_api.attr,
  	&mdev_type_attr_available_instances.attr,
  	NULL,
  };
@@ -636,6 +628,7 @@ static const struct vfio_device_ops vfio_ccw_dev_ops = {
  };
  
  struct mdev_driver vfio_ccw_mdev_driver = {
+	.device_api = VFIO_DEVICE_API_CCW_STRING,
  	.driver = {
  		.name = "vfio_ccw_mdev",
  		.owner = THIS_MODULE,
@@ -648,7 +641,7 @@ struct mdev_driver vfio_ccw_mdev_driver = {
  
  int vfio_ccw_mdev_reg(struct subchannel *sch)
  {
-	sprintf(sch->mdev_type.sysfs_name, "io");
+	strcat(sch->mdev_type.sysfs_name, "io");
  	sch->mdev_types[0] = &sch->mdev_type;
  	return mdev_register_parent(&sch->parent, &sch->dev,
  				    &vfio_ccw_mdev_driver, sch->mdev_types,
diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index ff25858b2ebbe..da21fd60877fb 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -529,17 +529,8 @@ 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_AP_STRING);
-}
-
-static MDEV_TYPE_ATTR_RO(device_api);
-
  static const 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,
  };
@@ -1454,6 +1445,7 @@ static const struct vfio_device_ops vfio_ap_matrix_dev_ops = {
  };
  
  static struct mdev_driver vfio_ap_matrix_driver = {
+	.device_api = VFIO_DEVICE_API_AP_STRING,
  	.driver = {
  		.name = "vfio_ap_mdev",
  		.owner = THIS_MODULE,
diff --git a/drivers/vfio/mdev/mdev_driver.c b/drivers/vfio/mdev/mdev_driver.c
index 5b3c94f4fb13d..60e8b9f6474e8 100644
--- a/drivers/vfio/mdev/mdev_driver.c
+++ b/drivers/vfio/mdev/mdev_driver.c
@@ -55,8 +55,10 @@ struct bus_type mdev_bus_type = {
   **/
  int mdev_register_driver(struct mdev_driver *drv)
  {
-	if (!drv->types_attrs)
+	if (!drv->types_attrs || !drv->device_api)
  		return -EINVAL;
+
+	/* initialize common driver fields */
  	drv->driver.bus = &mdev_bus_type;
  	return driver_register(&drv->driver);
  }
diff --git a/drivers/vfio/mdev/mdev_sysfs.c b/drivers/vfio/mdev/mdev_sysfs.c
index dd81b91afcf7d..20763f1aa9f5a 100644
--- a/drivers/vfio/mdev/mdev_sysfs.c
+++ b/drivers/vfio/mdev/mdev_sysfs.c
@@ -72,9 +72,30 @@ 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->mdev_driver->device_api);
+}
+static MDEV_TYPE_ATTR_RO(device_api);
+
+static struct attribute *mdev_types_core_attrs[] = {
+	&mdev_type_attr_create.attr,
+	&mdev_type_attr_device_api.attr,
+	NULL,
+};
+
+static struct attribute_group mdev_type_core_group = {
+	.attrs = mdev_types_core_attrs,
+};
+
+static const struct attribute_group *mdev_type_groups[] = {
+	&mdev_type_core_group,
+	NULL,
+};
+
  static void mdev_type_release(struct kobject *kobj)
  {
  	struct mdev_type *type = to_mdev_type(kobj);
@@ -84,8 +105,9 @@ static void mdev_type_release(struct kobject *kobj)
  }
  
  static struct kobj_type mdev_type_ktype = {
-	.sysfs_ops = &mdev_type_sysfs_ops,
-	.release = mdev_type_release,
+	.sysfs_ops	= &mdev_type_sysfs_ops,
+	.release	= mdev_type_release,
+	.default_groups	= mdev_type_groups,
  };
  
  int mdev_type_add(struct mdev_parent *parent, struct mdev_type *type)
@@ -100,10 +122,6 @@ int mdev_type_add(struct mdev_parent *parent, struct mdev_type *type)
  	if (ret)
  		return ret;
  
-	ret = sysfs_create_file(&type->kobj, &mdev_type_attr_create.attr);
-	if (ret)
-		goto attr_create_failed;
-
  	type->devices_kobj = kobject_create_and_add("devices", &type->kobj);
  	if (!type->devices_kobj) {
  		ret = -ENOMEM;
@@ -118,8 +136,6 @@ int mdev_type_add(struct mdev_parent *parent, struct mdev_type *type)
  attrs_failed:
  	kobject_put(type->devices_kobj);
  attr_devices_failed:
-	sysfs_remove_file(&type->kobj, &mdev_type_attr_create.attr);
-attr_create_failed:
  	kobject_del(&type->kobj);
  	kobject_put(&type->kobj);
  	return ret;
@@ -130,7 +146,6 @@ void mdev_type_remove(struct mdev_type *type)
  	sysfs_remove_files(&type->kobj, type->parent->mdev_driver->types_attrs);
  
  	kobject_put(type->devices_kobj);
-	sysfs_remove_file(&type->kobj, &mdev_type_attr_create.attr);
  	kobject_del(&type->kobj);
  	kobject_put(&type->kobj);
  }
diff --git a/include/linux/mdev.h b/include/linux/mdev.h
index ecf964d34f2ca..81e11e18b3e41 100644
--- a/include/linux/mdev.h
+++ b/include/linux/mdev.h
@@ -61,11 +61,6 @@ 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) \
@@ -73,12 +68,14 @@ struct mdev_type_attribute mdev_type_attr_##_name =		\
  
  /**
   * struct mdev_driver - Mediated device driver
+ * @device_api:	String to return for the device_api sysfs
   * @probe: called when new device created
   * @remove: called when device removed
   * @types_attrs: attributes to the type kobjects.
   * @driver: device driver structure
   **/
  struct mdev_driver {
+	const char *device_api;
  	int (*probe)(struct mdev_device *dev);
  	void (*remove)(struct mdev_device *dev);
  	const struct attribute * const *types_attrs;
diff --git a/samples/vfio-mdev/mbochs.c b/samples/vfio-mdev/mbochs.c
index 1069f561cb012..199846f01de92 100644
--- a/samples/vfio-mdev/mbochs.c
+++ b/samples/vfio-mdev/mbochs.c
@@ -1367,17 +1367,9 @@ 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 const 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,
  };
@@ -1391,6 +1383,7 @@ static const struct vfio_device_ops mbochs_dev_ops = {
  };
  
  static struct mdev_driver mbochs_driver = {
+	.device_api = VFIO_DEVICE_API_PCI_STRING,
  	.driver = {
  		.name = "mbochs",
  		.owner = THIS_MODULE,
diff --git a/samples/vfio-mdev/mdpy.c b/samples/vfio-mdev/mdpy.c
index 40b1c8a58157c..401a9a622673c 100644
--- a/samples/vfio-mdev/mdpy.c
+++ b/samples/vfio-mdev/mdpy.c
@@ -678,17 +678,9 @@ 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 const 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,
  };
@@ -701,6 +693,7 @@ static const struct vfio_device_ops mdpy_dev_ops = {
  };
  
  static struct mdev_driver mdpy_driver = {
+	.device_api = VFIO_DEVICE_API_PCI_STRING,
  	.driver = {
  		.name = "mdpy",
  		.owner = THIS_MODULE,
diff --git a/samples/vfio-mdev/mtty.c b/samples/vfio-mdev/mtty.c
index 029a19ef8ce7b..2a470424628af 100644
--- a/samples/vfio-mdev/mtty.c
+++ b/samples/vfio-mdev/mtty.c
@@ -1268,17 +1268,8 @@ 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 const struct attribute *mdev_types_attrs[] = {
  	&mdev_type_attr_name.attr,
-	&mdev_type_attr_device_api.attr,
  	&mdev_type_attr_available_instances.attr,
  	NULL,
  };
@@ -1291,6 +1282,7 @@ static const struct vfio_device_ops mtty_dev_ops = {
  };
  
  static struct mdev_driver mtty_driver = {
+	.device_api = VFIO_DEVICE_API_PCI_STRING,
  	.driver = {
  		.name = "mtty",
  		.owner = THIS_MODULE,






