vfio/mdev: Correct the function signatures for the mdev_type_attributes

The driver core standard is to pass in the properly typed object, the
properly typed attribute and the buffer data. It stems from the root
kobject method:

  ssize_t (*show)(struct kobject *kobj, struct kobj_attribute *attr,..)

Each subclass of kobject should provide their own function with the same
signature but more specific types, eg struct device uses:

  ssize_t (*show)(struct device *dev, struct device_attribute *attr,..)

In this case the existing signature is:

  ssize_t (*show)(struct kobject *kobj, struct device *dev,..)

Where kobj is a 'struct mdev_type *' and dev is 'mdev_type->parent->dev'.

Change the mdev_type related sysfs attribute functions to:

  ssize_t (*show)(struct mdev_type *mtype, struct mdev_type_attribute *attr,..)

In order to restore type safety and match the driver core standard

There are no current users of 'attr', but if it is ever needed it would be
hard to add in retroactively, so do it now.

Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Message-Id: <18-v2-d36939638fc6+d54-vfio2_jgg@nvidia.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

9 files changed, 90 insertions, 62 deletions

diff --git a/drivers/gpu/drm/i915/gvt/gvt.c b/drivers/gpu/drm/i915/gvt/gvt.c
index 4b47a18e9dfa..3703814a669b 100644
--- a/drivers/gpu/drm/i915/gvt/gvt.c
+++ b/drivers/gpu/drm/i915/gvt/gvt.c
@@ -54,14 +54,15 @@ intel_gvt_find_vgpu_type(struct intel_gvt *gvt, unsigned int type_group_id)
 	return &gvt->types[type_group_id];
 }
 
-static ssize_t available_instances_show(struct kobject *kobj,
-					struct device *dev, char *buf)
+static ssize_t available_instances_show(struct mdev_type *mtype,
+					struct mdev_type_attribute *attr,
+					char *buf)
 {
 	struct intel_vgpu_type *type;
 	unsigned int num = 0;
-	void *gvt = kdev_to_i915(dev)->gvt;
+	void *gvt = kdev_to_i915(mtype_get_parent_dev(mtype))->gvt;
 
-	type = intel_gvt_find_vgpu_type(gvt, mtype_get_type_group_id(kobj));
+	type = intel_gvt_find_vgpu_type(gvt, mtype_get_type_group_id(mtype));
 	if (!type)
 		num = 0;
 	else
@@ -70,19 +71,19 @@ static ssize_t available_instances_show(struct kobject *kobj,
 	return sprintf(buf, "%u\n", num);
 }
 
-static ssize_t device_api_show(struct kobject *kobj, struct device *dev,
-		char *buf)
+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 kobject *kobj, struct device *dev,
-		char *buf)
+static ssize_t description_show(struct mdev_type *mtype,
+				struct mdev_type_attribute *attr, char *buf)
 {
 	struct intel_vgpu_type *type;
-	void *gvt = kdev_to_i915(dev)->gvt;
+	void *gvt = kdev_to_i915(mtype_get_parent_dev(mtype))->gvt;
 
-	type = intel_gvt_find_vgpu_type(gvt, mtype_get_type_group_id(kobj));
+	type = intel_gvt_find_vgpu_type(gvt, mtype_get_type_group_id(mtype));
 	if (!type)
 		return 0;
 
diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
index 10407cf67583..491a64c61fff 100644
--- a/drivers/s390/cio/vfio_ccw_ops.c
+++ b/drivers/s390/cio/vfio_ccw_ops.c
@@ -71,23 +71,26 @@ static int vfio_ccw_mdev_notifier(struct notifier_block *nb,
 	return NOTIFY_DONE;
 }
 
-static ssize_t name_show(struct kobject *kobj, struct device *dev, char *buf)
+static ssize_t name_show(struct mdev_type *mtype,
+			 struct mdev_type_attribute *attr, char *buf)
 {
 	return sprintf(buf, "I/O subchannel (Non-QDIO)\n");
 }
 static MDEV_TYPE_ATTR_RO(name);
 
-static ssize_t device_api_show(struct kobject *kobj, struct device *dev,
-			       char *buf)
+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 kobject *kobj,
-					struct device *dev, char *buf)
+static ssize_t available_instances_show(struct mdev_type *mtype,
+					struct mdev_type_attribute *attr,
+					char *buf)
 {
-	struct vfio_ccw_private *private = dev_get_drvdata(dev);
+	struct vfio_ccw_private *private =
+		dev_get_drvdata(mtype_get_parent_dev(mtype));
 
 	return sprintf(buf, "%d\n", atomic_read(&private->avail));
 }
diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index d319152dd484..0ce00c9311d3 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -366,15 +366,17 @@ static int vfio_ap_mdev_remove(struct mdev_device *mdev)
 	return 0;
 }
 
-static ssize_t name_show(struct kobject *kobj, struct device *dev, char *buf)
+static ssize_t name_show(struct mdev_type *mtype,
+			 struct mdev_type_attribute *attr, char *buf)
 {
 	return sprintf(buf, "%s\n", VFIO_AP_MDEV_NAME_HWVIRT);
 }
 
 static MDEV_TYPE_ATTR_RO(name);
 
-static ssize_t available_instances_show(struct kobject *kobj,
-					struct device *dev, char *buf)
+static ssize_t available_instances_show(struct mdev_type *mtype,
+					struct mdev_type_attribute *attr,
+					char *buf)
 {
 	return sprintf(buf, "%d\n",
 		       atomic_read(&matrix_dev->available_instances));
@@ -382,8 +384,8 @@ static ssize_t available_instances_show(struct kobject *kobj,
 
 static MDEV_TYPE_ATTR_RO(available_instances);
 
-static ssize_t device_api_show(struct kobject *kobj, struct device *dev,
-			       char *buf)
+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);
 }
diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c
index 10eff33ce1f2..2a85d6fcb7dd 100644
--- a/drivers/vfio/mdev/mdev_core.c
+++ b/drivers/vfio/mdev/mdev_core.c
@@ -47,12 +47,22 @@ EXPORT_SYMBOL(mdev_get_type_group_id);
  * Used in mdev_type_attribute sysfs functions to return the index in the
  * supported_type_groups that the sysfs is called from.
  */
-unsigned int mtype_get_type_group_id(struct kobject *mtype_kobj)
+unsigned int mtype_get_type_group_id(struct mdev_type *mtype)
 {
-	return container_of(mtype_kobj, struct mdev_type, kobj)->type_group_id;
+	return mtype->type_group_id;
 }
 EXPORT_SYMBOL(mtype_get_type_group_id);
 
+/*
+ * Used in mdev_type_attribute sysfs functions to return the parent struct
+ * device
+ */
+struct device *mtype_get_parent_dev(struct mdev_type *mtype)
+{
+	return mtype->parent->dev;
+}
+EXPORT_SYMBOL(mtype_get_parent_dev);
+
 /* Should be called holding parent_list_lock */
 static struct mdev_parent *__find_parent_device(struct device *dev)
 {
diff --git a/drivers/vfio/mdev/mdev_sysfs.c b/drivers/vfio/mdev/mdev_sysfs.c
index 712fbc78b12e..f5cf1931c54e 100644
--- a/drivers/vfio/mdev/mdev_sysfs.c
+++ b/drivers/vfio/mdev/mdev_sysfs.c
@@ -26,7 +26,7 @@ static ssize_t mdev_type_attr_show(struct kobject *kobj,
 	ssize_t ret = -EIO;
 
 	if (attr->show)
-		ret = attr->show(kobj, type->parent->dev, buf);
+		ret = attr->show(type, attr, buf);
 	return ret;
 }
 
@@ -39,7 +39,7 @@ static ssize_t mdev_type_attr_store(struct kobject *kobj,
 	ssize_t ret = -EIO;
 
 	if (attr->store)
-		ret = attr->store(&type->kobj, type->parent->dev, buf, count);
+		ret = attr->store(type, attr, buf, count);
 	return ret;
 }
 
@@ -48,8 +48,9 @@ static const struct sysfs_ops mdev_type_sysfs_ops = {
 	.store = mdev_type_attr_store,
 };
 
-static ssize_t create_store(struct kobject *kobj, struct device *dev,
-			    const char *buf, size_t count)
+static ssize_t create_store(struct mdev_type *mtype,
+			    struct mdev_type_attribute *attr, const char *buf,
+			    size_t count)
 {
 	char *str;
 	guid_t uuid;
@@ -67,7 +68,7 @@ static ssize_t create_store(struct kobject *kobj, struct device *dev,
 	if (ret)
 		return ret;
 
-	ret = mdev_device_create(to_mdev_type(kobj), &uuid);
+	ret = mdev_device_create(mtype, &uuid);
 	if (ret)
 		return ret;
 
diff --git a/include/linux/mdev.h b/include/linux/mdev.h
index c3a800051d61..1fb34ea394ad 100644
--- a/include/linux/mdev.h
+++ b/include/linux/mdev.h
@@ -47,7 +47,8 @@ static inline struct device *mdev_get_iommu_device(struct mdev_device *mdev)
 }
 
 unsigned int mdev_get_type_group_id(struct mdev_device *mdev);
-unsigned int mtype_get_type_group_id(struct kobject *mtype_kobj);
+unsigned int mtype_get_type_group_id(struct mdev_type *mtype);
+struct device *mtype_get_parent_dev(struct mdev_type *mtype);
 
 /**
  * struct mdev_parent_ops - Structure to be registered for each parent device to
@@ -123,9 +124,11 @@ struct mdev_parent_ops {
 /* interface for exporting mdev supported type attributes */
 struct mdev_type_attribute {
 	struct attribute attr;
-	ssize_t (*show)(struct kobject *kobj, struct device *dev, char *buf);
-	ssize_t (*store)(struct kobject *kobj, struct device *dev,
-			 const char *buf, size_t count);
+	ssize_t (*show)(struct mdev_type *mtype,
+			struct mdev_type_attribute *attr, char *buf);
+	ssize_t (*store)(struct mdev_type *mtype,
+			 struct mdev_type_attribute *attr, const char *buf,
+			 size_t count);
 };
 
 #define MDEV_TYPE_ATTR(_name, _mode, _show, _store)		\
diff --git a/samples/vfio-mdev/mbochs.c b/samples/vfio-mdev/mbochs.c
index ac4d0dc24907..861c76914e76 100644
--- a/samples/vfio-mdev/mbochs.c
+++ b/samples/vfio-mdev/mbochs.c
@@ -1330,37 +1330,41 @@ static const struct attribute_group *mdev_dev_groups[] = {
 	NULL,
 };
 
-static ssize_t
-name_show(struct kobject *kobj, struct device *dev, char *buf)
+static ssize_t name_show(struct mdev_type *mtype,
+			 struct mdev_type_attribute *attr, char *buf)
 {
-	return sprintf(buf, "%s\n", kobj->name);
+	const struct mbochs_type *type =
+		&mbochs_types[mtype_get_type_group_id(mtype)];
+
+	return sprintf(buf, "%s\n", type->name);
 }
 static MDEV_TYPE_ATTR_RO(name);
 
-static ssize_t
-description_show(struct kobject *kobj, struct device *dev, char *buf)
+static ssize_t description_show(struct mdev_type *mtype,
+				struct mdev_type_attribute *attr, char *buf)
 {
 	const struct mbochs_type *type =
-		&mbochs_types[mtype_get_type_group_id(kobj)];
+		&mbochs_types[mtype_get_type_group_id(mtype)];
 
 	return sprintf(buf, "virtual display, %d MB video memory\n",
 		       type ? type->mbytes  : 0);
 }
 static MDEV_TYPE_ATTR_RO(description);
 
-static ssize_t
-available_instances_show(struct kobject *kobj, struct device *dev, char *buf)
+static ssize_t available_instances_show(struct mdev_type *mtype,
+					struct mdev_type_attribute *attr,
+					char *buf)
 {
 	const struct mbochs_type *type =
-		&mbochs_types[mtype_get_type_group_id(kobj)];
+		&mbochs_types[mtype_get_type_group_id(mtype)];
 	int count = (max_mbytes - mbochs_used_mbytes) / type->mbytes;
 
 	return sprintf(buf, "%d\n", count);
 }
 static MDEV_TYPE_ATTR_RO(available_instances);
 
-static ssize_t device_api_show(struct kobject *kobj, struct device *dev,
-			       char *buf)
+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);
 }
diff --git a/samples/vfio-mdev/mdpy.c b/samples/vfio-mdev/mdpy.c
index da88fd7dd423..885b88ea20e2 100644
--- a/samples/vfio-mdev/mdpy.c
+++ b/samples/vfio-mdev/mdpy.c
@@ -652,18 +652,21 @@ static const struct attribute_group *mdev_dev_groups[] = {
 	NULL,
 };
 
-static ssize_t
-name_show(struct kobject *kobj, struct device *dev, char *buf)
+static ssize_t name_show(struct mdev_type *mtype,
+			 struct mdev_type_attribute *attr, char *buf)
 {
-	return sprintf(buf, "%s\n", kobj->name);
+	const struct mdpy_type *type =
+		&mdpy_types[mtype_get_type_group_id(mtype)];
+
+	return sprintf(buf, "%s\n", type->name);
 }
 static MDEV_TYPE_ATTR_RO(name);
 
-static ssize_t
-description_show(struct kobject *kobj, struct device *dev, char *buf)
+static ssize_t description_show(struct mdev_type *mtype,
+				struct mdev_type_attribute *attr, char *buf)
 {
 	const struct mdpy_type *type =
-		&mdpy_types[mtype_get_type_group_id(kobj)];
+		&mdpy_types[mtype_get_type_group_id(mtype)];
 
 	return sprintf(buf, "virtual display, %dx%d framebuffer\n",
 		       type ? type->width  : 0,
@@ -671,15 +674,16 @@ description_show(struct kobject *kobj, struct device *dev, char *buf)
 }
 static MDEV_TYPE_ATTR_RO(description);
 
-static ssize_t
-available_instances_show(struct kobject *kobj, struct device *dev, char *buf)
+static ssize_t available_instances_show(struct mdev_type *mtype,
+					struct mdev_type_attribute *attr,
+					char *buf)
 {
 	return sprintf(buf, "%d\n", max_devices - mdpy_count);
 }
 static MDEV_TYPE_ATTR_RO(available_instances);
 
-static ssize_t device_api_show(struct kobject *kobj, struct device *dev,
-			       char *buf)
+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);
 }
diff --git a/samples/vfio-mdev/mtty.c b/samples/vfio-mdev/mtty.c
index f2e36c06ac6a..b9b24be4abda 100644
--- a/samples/vfio-mdev/mtty.c
+++ b/samples/vfio-mdev/mtty.c
@@ -1292,23 +1292,24 @@ static const struct attribute_group *mdev_dev_groups[] = {
 	NULL,
 };
 
-static ssize_t
-name_show(struct kobject *kobj, struct device *dev, char *buf)
+static ssize_t name_show(struct mdev_type *mtype,
+			 struct mdev_type_attribute *attr, char *buf)
 {
 	static const char *name_str[2] = { "Single port serial",
 					   "Dual port serial" };
 
 	return sysfs_emit(buf, "%s\n",
-			  name_str[mtype_get_type_group_id(kobj)]);
+			  name_str[mtype_get_type_group_id(mtype)]);
 }
 
 static MDEV_TYPE_ATTR_RO(name);
 
-static ssize_t
-available_instances_show(struct kobject *kobj, struct device *dev, char *buf)
+static ssize_t available_instances_show(struct mdev_type *mtype,
+					struct mdev_type_attribute *attr,
+					char *buf)
 {
 	struct mdev_state *mds;
-	unsigned int ports = mtype_get_type_group_id(kobj) + 1;
+	unsigned int ports = mtype_get_type_group_id(mtype) + 1;
 	int used = 0;
 
 	list_for_each_entry(mds, &mdev_devices_list, next)
@@ -1319,9 +1320,8 @@ available_instances_show(struct kobject *kobj, struct device *dev, char *buf)
 
 static MDEV_TYPE_ATTR_RO(available_instances);
 
-
-static ssize_t device_api_show(struct kobject *kobj, struct device *dev,
-			       char *buf)
+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);
 }