Merge tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Don't destroy user event fields when removal fails

   User event fields are destroyed before the event is removed from
   visibility. But that can fail leaving the still visible event with no
   fields. Move the destroying of the fields to after the event is
   successfully removed from visibility.

 - Initialize function graph state is fork before calling
   copy_exec_state()

   For non-CLONE_VM forks, copy_exec_state() allocates a new
   task_exec_state. If that allocation fails, ftrace_graph_exit_task()
   will free the tasks ret_stack pointer. Since that pointer is still
   using the parent's ret_stack, it mistakenly frees the parent's
   pointer too.

   Call ftrace_graph_init() on the task first which will NULL out the
   new tasks's ret_stack and if the copy fails, it will not free
   anything.

 - Remove FGRAPH_MAX_INDEX

   The macro FGRAPH_MAX_INDEX was added but never used. Remove it.

 - Save ent_size in function graph printing of nested functions

   The function graph tracer needs to look at the next event to see if
   the next event is the return of the current function entry. If it is,
   it prints a single line:

	ktime_get();

   Otherwise it prints it like a nested function:

	tick_nohz_irq_exit() {
	    ktime_get();
	    kcpustat_irq_exit();
	}

   In order to look at the next event, it must save the current event so
   that it has the information to print from it. It saves the event in
   the iterator descriptor called "ent". What it doesn't save is the
   ent_size of the event which is now used to know if the function graph
   arguments are to be printed. The peek doesn't save the size so the
   size used happens to be that of the size of the last event that was
   seen.

   Save the entry event size in the iterator descriptor so that the
   correct size is used.

 - Fix several errors with freeing data in the histogram code

   The histogram code had a lot of leaked or or incorrect accounting
   when failures happen. Correct them.

 - Fix histogram regression of .percent and .graph modifiers

   Up until 6.3 histogram values could have "percent" or "graph"
   modifiers that changed how they were printed. But a change that added
   restricting histograms values from being strings, stack traces and
   other modifiers inadvertently prevented them from using the percent
   and graph modifiers, which were legal use cases for values.

   Put back the percent and graph modifiers.

 - Fix various typos in the comments

 - Set the trace_clock before initializing a histogram with clock
   argument

   The histogram API allows the user to specific which trace clock to
   use via a "clock=" string. The histogram is set up first before the
   clock is checked. If the passed in clock is not valid, it exits
   without fully fixing up the histogram leaving it on the list and a
   use-after-free can trigger.

   Update the clock argument first and if it fails then exit gracefully
   before the histogram trigger is placed on any lists.

 - Restore :mod: trailer after parsing in ftrace_set_clr_event

   The function ftrace_set_clr_event() modifies the parse string and
   needs to put it back to what was passed in. It searches for ":mod:"
   via a strsep() but fails to put back the first ':' in the string.

   Add back the ':' in the passed in string.

 - Take trace_array reference when opening a tracer options file

   The options files are dynamically created and some tracers add their
   own options. When a tracer adds their own list of options, the
   trace_array holding them has an array to hold the list of options for
   each tracer. This array increases in size via a krealloc(), and the
   new entry gets a newly allocated array to hold the options of the new
   tracer being added.

   The element in each entry of the tracer's option array holds a
   pointer back to the trace_array, a pointer to the tracer it is
   associated to, a pointer to the flags of the option.

   The issue is that these arrays are freed when the trace_array is
   freed when its instance it represents is removed from the instances
   directory. There's a race that an open of one of these options files
   can happen when the instance is being removed.

   Add a new helper function to be called by the open function of the
   options file to iterate all existing trace_arrays under a lock and
   find the one that has the given option element in one of it's tracer
   arrays. If found, then update the associated trace_array's reference
   counter to keep it from being freed. If not found, have the open call
   return -ENODEV.

 - Disable interrupts when acquiring the lock in rb_wake_up_waiters()

   The function rb_wake_up_waiters() assumes it will be called in
   interrupt context and does not disable irqs when taking
   cpu_buffer->reader_lock, which can be called in hard interrupt
   context. The issue is in PREEMPT_RT, this function is called in
   thread context leaving this lock open to a deadlock.

   Take the lock with interrupts disabled.

 - Use rcu_assign_pointer() for tmp_ops filter hash

   The tmp_ops used in update_ftrace_direct_mod() assigns its
   filter_hash field directly, but that field is annotated as __rcu and
   sparse complains. Assign it with rcu_assign_pointer()

 - Fix use-after-free in enable_trigger_private_data_free()

   The trace_event_call is accessed through the event_trigger_data's
   trace_event_file pointer to put the trace_event_call on freeing. The
   issue is that the trace_event_file data may have been freed already
   causing a use-after-free. Add a field to the event_trigger_data that
   points directly to the trace_event_call so that it can decrement its
   reference directly without needing to go through the
   trace_event_file.

 - Fix accounting of buffer data remote headers

   trace_buffer_desc_size() and trace_remote_alloc_buffer() undercount
   the number of pages is needed for the asked for size as it doesn't
   take into account the meta data on each page. Add a helper function
   to do the calculation properly and use that in these functions.

 - Catch nr_page_va overflow in ring_buffer_desc sizing

   The number of pages per remote ring buffer is capped by
   ring_buffer_desc::nr_page_va (32 bits). A buffer_size large enough to
   overflow that field would silently allocate a descriptor smaller than
   what was asked for.

 - Do not resize the subbuf order if any per_cpu buffer is disabled

   The mmapping of ring buffers disables resizing the subbuffers, but it
   is done per-cpu whereas the subbuf size change is done for all the
   per_cpu buffers under the buffer->mutex. It could change the size of
   some while the mapping is happening on others. Have the resize of the
   subbuf order check all the per_cpu buffers under the lock to see if
   any of them is disabled before starting and causing an inconsistency
   between buffers that are being mapped.

* tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (25 commits)
  ring-buffer: Check resize_disabled before publishing the new subbuf order
  tracing/remotes: Catch nr_page_va overflow in ring_buffer_desc sizing
  tracing/remotes: Account for ring buffer page header in size calculation
  tracing: Don't dereference trace_event_file in deferred trigger free
  ftrace: Use rcu_assign_pointer() for tmp_ops filter hash
  ring-buffer: Acquire the lock with irqsave in rb_wake_up_waiters()
  tracing: Take trace_array reference when opening a tracer options file
  tracing: Fix ring_buffer_read_page_size() kernel-doc
  tracing: Restore :mod: trailer after parsing in ftrace_set_clr_event()
  tracing: Fix memory corruption from a "STACKTRACE" histogram key
  tracing: Fix memory corruption from the histogram stacktrace modifier
  tracing: Undo the registration when enabling the histogram trigger fails
  tracing: Take the reference before publishing the named histogram trigger
  tracing: Set the trace clock before registering the histogram trigger
  tracing: Fix typo "preceeded" in comment
  tracing: Fix typo "availabe" in comment
  tracing: Let histogram values keep the percent and graph modifiers
  tracing: Keep the entry count when the histogram stats allocation fails
  tracing: Free histogram the field rejected for a bad modifier
  tracing: Free histogram the var ref when its initialization fails
  ...

6 files changed, 691 insertions, 0 deletions

diff --git a/drivers/vfio/mdev/Kconfig b/drivers/vfio/mdev/Kconfig
new file mode 100644
index 000000000..e5fb84e07
--- /dev/null
+++ b/drivers/vfio/mdev/Kconfig
@@ -0,0 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+config VFIO_MDEV
+	tristate
diff --git a/drivers/vfio/mdev/Makefile b/drivers/vfio/mdev/Makefile
new file mode 100644
index 000000000..7c236ba1b
--- /dev/null
+++ b/drivers/vfio/mdev/Makefile
@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+mdev-y := mdev_core.o mdev_sysfs.o mdev_driver.o
+
+obj-$(CONFIG_VFIO_MDEV) += mdev.o
diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c
new file mode 100644
index 000000000..3b4aa0632
--- /dev/null
+++ b/drivers/vfio/mdev/mdev_core.c
@@ -0,0 +1,275 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Mediated device Core Driver
+ *
+ * Copyright (c) 2016, NVIDIA CORPORATION. All rights reserved.
+ *     Author: Neo Jia <cjia@nvidia.com>
+ *             Kirti Wankhede <kwankhede@nvidia.com>
+ */
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/sysfs.h>
+#include <linux/mdev.h>
+
+#include "mdev_private.h"
+
+#define DRIVER_VERSION		"0.1"
+#define DRIVER_AUTHOR		"NVIDIA Corporation"
+#define DRIVER_DESC		"Mediated device Core Driver"
+
+static struct class_compat *mdev_bus_compat_class;
+
+static LIST_HEAD(mdev_list);
+static DEFINE_MUTEX(mdev_list_lock);
+
+/* Caller must hold parent unreg_sem read or write lock */
+static void mdev_device_remove_common(struct mdev_device *mdev)
+{
+	struct mdev_parent *parent = mdev->type->parent;
+
+	mdev_remove_sysfs_files(mdev);
+	device_del(&mdev->dev);
+	lockdep_assert_held(&parent->unreg_sem);
+	/* Balances with device_initialize() */
+	put_device(&mdev->dev);
+}
+
+static int mdev_device_remove_cb(struct device *dev, void *data)
+{
+	if (dev->bus == &mdev_bus_type)
+		mdev_device_remove_common(to_mdev_device(dev));
+	return 0;
+}
+
+/*
+ * mdev_register_parent: Register a device as parent for mdevs
+ * @parent: parent structure registered
+ * @dev: device structure representing parent device.
+ * @mdev_driver: Device driver to bind to the newly created mdev
+ * @types: Array of supported mdev types
+ * @nr_types: Number of entries in @types
+ *
+ * Registers the @parent stucture as a parent for mdev types and thus mdev
+ * devices.  The caller needs to hold a reference on @dev that must not be
+ * released until after the call to mdev_unregister_parent().
+ *
+ * Returns a negative value on error, otherwise 0.
+ */
+int mdev_register_parent(struct mdev_parent *parent, struct device *dev,
+		struct mdev_driver *mdev_driver, struct mdev_type **types,
+		unsigned int nr_types)
+{
+	char *env_string = "MDEV_STATE=registered";
+	char *envp[] = { env_string, NULL };
+	int ret;
+
+	memset(parent, 0, sizeof(*parent));
+	init_rwsem(&parent->unreg_sem);
+	parent->dev = dev;
+	parent->mdev_driver = mdev_driver;
+	parent->types = types;
+	parent->nr_types = nr_types;
+	atomic_set(&parent->available_instances, mdev_driver->max_instances);
+
+	ret = parent_create_sysfs_files(parent);
+	if (ret)
+		return ret;
+
+	ret = class_compat_create_link(mdev_bus_compat_class, dev);
+	if (ret)
+		dev_warn(dev, "Failed to create compatibility class link\n");
+
+	dev_info(dev, "MDEV: Registered\n");
+	kobject_uevent_env(&dev->kobj, KOBJ_CHANGE, envp);
+	return 0;
+}
+EXPORT_SYMBOL(mdev_register_parent);
+
+/*
+ * mdev_unregister_parent : Unregister a parent device
+ * @parent: parent structure to unregister
+ */
+void mdev_unregister_parent(struct mdev_parent *parent)
+{
+	char *env_string = "MDEV_STATE=unregistered";
+	char *envp[] = { env_string, NULL };
+
+	dev_info(parent->dev, "MDEV: Unregistering\n");
+
+	down_write(&parent->unreg_sem);
+	class_compat_remove_link(mdev_bus_compat_class, parent->dev);
+	device_for_each_child(parent->dev, NULL, mdev_device_remove_cb);
+	parent_remove_sysfs_files(parent);
+	up_write(&parent->unreg_sem);
+
+	kobject_uevent_env(&parent->dev->kobj, KOBJ_CHANGE, envp);
+}
+EXPORT_SYMBOL(mdev_unregister_parent);
+
+static void mdev_device_release(struct device *dev)
+{
+	struct mdev_device *mdev = to_mdev_device(dev);
+	struct mdev_parent *parent = mdev->type->parent;
+
+	mutex_lock(&mdev_list_lock);
+	list_del(&mdev->next);
+	if (!parent->mdev_driver->get_available)
+		atomic_inc(&parent->available_instances);
+	mutex_unlock(&mdev_list_lock);
+
+	/* Pairs with the get in mdev_device_create() */
+	kobject_put(&mdev->type->kobj);
+
+	dev_dbg(&mdev->dev, "MDEV: destroying\n");
+	kfree(mdev);
+}
+
+int mdev_device_create(struct mdev_type *type, const guid_t *uuid)
+{
+	int ret;
+	struct mdev_device *mdev, *tmp;
+	struct mdev_parent *parent = type->parent;
+	struct mdev_driver *drv = parent->mdev_driver;
+
+	mutex_lock(&mdev_list_lock);
+
+	/* Check for duplicate */
+	list_for_each_entry(tmp, &mdev_list, next) {
+		if (guid_equal(&tmp->uuid, uuid)) {
+			mutex_unlock(&mdev_list_lock);
+			return -EEXIST;
+		}
+	}
+
+	if (!drv->get_available) {
+		/*
+		 * Note: that non-atomic read and dec is fine here because
+		 * all modifications are under mdev_list_lock.
+		 */
+		if (!atomic_read(&parent->available_instances)) {
+			mutex_unlock(&mdev_list_lock);
+			return -EUSERS;
+		}
+		atomic_dec(&parent->available_instances);
+	}
+
+	mdev = kzalloc_obj(*mdev);
+	if (!mdev) {
+		mutex_unlock(&mdev_list_lock);
+		return -ENOMEM;
+	}
+
+	device_initialize(&mdev->dev);
+	mdev->dev.parent  = parent->dev;
+	mdev->dev.bus = &mdev_bus_type;
+	mdev->dev.release = mdev_device_release;
+	mdev->dev.groups = mdev_device_groups;
+	mdev->type = type;
+	/* Pairs with the put in mdev_device_release() */
+	kobject_get(&type->kobj);
+
+	guid_copy(&mdev->uuid, uuid);
+	list_add(&mdev->next, &mdev_list);
+	mutex_unlock(&mdev_list_lock);
+
+	ret = dev_set_name(&mdev->dev, "%pUl", uuid);
+	if (ret)
+		goto out_put_device;
+
+	/* Check if parent unregistration has started */
+	if (!down_read_trylock(&parent->unreg_sem)) {
+		ret = -ENODEV;
+		goto out_put_device;
+	}
+
+	ret = device_add(&mdev->dev);
+	if (ret)
+		goto out_unlock;
+
+	ret = device_driver_attach(&drv->driver, &mdev->dev);
+	if (ret)
+		goto out_del;
+
+	ret = mdev_create_sysfs_files(mdev);
+	if (ret)
+		goto out_del;
+
+	mdev->active = true;
+	dev_dbg(&mdev->dev, "MDEV: created\n");
+	up_read(&parent->unreg_sem);
+
+	return 0;
+
+out_del:
+	device_del(&mdev->dev);
+out_unlock:
+	up_read(&parent->unreg_sem);
+out_put_device:
+	put_device(&mdev->dev);
+	return ret;
+}
+
+int mdev_device_remove(struct mdev_device *mdev)
+{
+	struct mdev_device *tmp;
+	struct mdev_parent *parent = mdev->type->parent;
+
+	mutex_lock(&mdev_list_lock);
+	list_for_each_entry(tmp, &mdev_list, next) {
+		if (tmp == mdev)
+			break;
+	}
+
+	if (tmp != mdev) {
+		mutex_unlock(&mdev_list_lock);
+		return -ENODEV;
+	}
+
+	if (!mdev->active) {
+		mutex_unlock(&mdev_list_lock);
+		return -EAGAIN;
+	}
+
+	mdev->active = false;
+	mutex_unlock(&mdev_list_lock);
+
+	/* Check if parent unregistration has started */
+	if (!down_read_trylock(&parent->unreg_sem))
+		return -ENODEV;
+
+	mdev_device_remove_common(mdev);
+	up_read(&parent->unreg_sem);
+	return 0;
+}
+
+static int __init mdev_init(void)
+{
+	int ret;
+
+	ret = bus_register(&mdev_bus_type);
+	if (ret)
+		return ret;
+
+	mdev_bus_compat_class = class_compat_register("mdev_bus");
+	if (!mdev_bus_compat_class) {
+		bus_unregister(&mdev_bus_type);
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+static void __exit mdev_exit(void)
+{
+	class_compat_unregister(mdev_bus_compat_class);
+	bus_unregister(&mdev_bus_type);
+}
+
+subsys_initcall(mdev_init)
+module_exit(mdev_exit)
+
+MODULE_VERSION(DRIVER_VERSION);
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR(DRIVER_AUTHOR);
+MODULE_DESCRIPTION(DRIVER_DESC);
diff --git a/drivers/vfio/mdev/mdev_driver.c b/drivers/vfio/mdev/mdev_driver.c
new file mode 100644
index 000000000..ad5b83480
--- /dev/null
+++ b/drivers/vfio/mdev/mdev_driver.c
@@ -0,0 +1,75 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * MDEV driver
+ *
+ * Copyright (c) 2016, NVIDIA CORPORATION. All rights reserved.
+ *     Author: Neo Jia <cjia@nvidia.com>
+ *             Kirti Wankhede <kwankhede@nvidia.com>
+ */
+
+#include <linux/iommu.h>
+#include <linux/mdev.h>
+
+#include "mdev_private.h"
+
+static int mdev_probe(struct device *dev)
+{
+	struct mdev_driver *drv =
+		container_of(dev->driver, struct mdev_driver, driver);
+
+	if (!drv->probe)
+		return 0;
+	return drv->probe(to_mdev_device(dev));
+}
+
+static void mdev_remove(struct device *dev)
+{
+	struct mdev_driver *drv =
+		container_of(dev->driver, struct mdev_driver, driver);
+
+	if (drv->remove)
+		drv->remove(to_mdev_device(dev));
+}
+
+static int mdev_match(struct device *dev, const struct device_driver *drv)
+{
+	/*
+	 * No drivers automatically match. Drivers are only bound by explicit
+	 * device_driver_attach()
+	 */
+	return 0;
+}
+
+const struct bus_type mdev_bus_type = {
+	.name		= "mdev",
+	.probe		= mdev_probe,
+	.remove		= mdev_remove,
+	.match		= mdev_match,
+};
+
+/**
+ * mdev_register_driver - register a new MDEV driver
+ * @drv: the driver to register
+ *
+ * Returns a negative value on error, otherwise 0.
+ **/
+int mdev_register_driver(struct mdev_driver *drv)
+{
+	if (!drv->device_api)
+		return -EINVAL;
+
+	/* initialize common driver fields */
+	drv->driver.bus = &mdev_bus_type;
+	return driver_register(&drv->driver);
+}
+EXPORT_SYMBOL(mdev_register_driver);
+
+/*
+ * mdev_unregister_driver - unregister MDEV driver
+ * @drv: the driver to unregister
+ */
+void mdev_unregister_driver(struct mdev_driver *drv)
+{
+	driver_unregister(&drv->driver);
+}
+EXPORT_SYMBOL(mdev_unregister_driver);
diff --git a/drivers/vfio/mdev/mdev_private.h b/drivers/vfio/mdev/mdev_private.h
new file mode 100644
index 000000000..5f61acd0f
--- /dev/null
+++ b/drivers/vfio/mdev/mdev_private.h
@@ -0,0 +1,30 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Mediated device internal definitions
+ *
+ * Copyright (c) 2016, NVIDIA CORPORATION. All rights reserved.
+ *     Author: Neo Jia <cjia@nvidia.com>
+ *             Kirti Wankhede <kwankhede@nvidia.com>
+ */
+
+#ifndef MDEV_PRIVATE_H
+#define MDEV_PRIVATE_H
+
+extern const struct bus_type mdev_bus_type;
+extern const struct attribute_group *mdev_device_groups[];
+
+#define to_mdev_type_attr(_attr)	\
+	container_of(_attr, struct mdev_type_attribute, attr)
+#define to_mdev_type(_kobj)		\
+	container_of(_kobj, struct mdev_type, kobj)
+
+int  parent_create_sysfs_files(struct mdev_parent *parent);
+void parent_remove_sysfs_files(struct mdev_parent *parent);
+
+int  mdev_create_sysfs_files(struct mdev_device *mdev);
+void mdev_remove_sysfs_files(struct mdev_device *mdev);
+
+int mdev_device_create(struct mdev_type *kobj, const guid_t *uuid);
+int  mdev_device_remove(struct mdev_device *dev);
+
+#endif /* MDEV_PRIVATE_H */
diff --git a/drivers/vfio/mdev/mdev_sysfs.c b/drivers/vfio/mdev/mdev_sysfs.c
new file mode 100644
index 000000000..b2596020e
--- /dev/null
+++ b/drivers/vfio/mdev/mdev_sysfs.c
@@ -0,0 +1,302 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * File attributes for Mediated devices
+ *
+ * Copyright (c) 2016, NVIDIA CORPORATION. All rights reserved.
+ *     Author: Neo Jia <cjia@nvidia.com>
+ *             Kirti Wankhede <kwankhede@nvidia.com>
+ */
+
+#include <linux/sysfs.h>
+#include <linux/ctype.h>
+#include <linux/slab.h>
+#include <linux/mdev.h>
+
+#include "mdev_private.h"
+
+struct mdev_type_attribute {
+	struct attribute attr;
+	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_RO(_name) \
+	struct mdev_type_attribute mdev_type_attr_##_name = __ATTR_RO(_name)
+#define MDEV_TYPE_ATTR_WO(_name) \
+	struct mdev_type_attribute mdev_type_attr_##_name = __ATTR_WO(_name)
+
+static ssize_t mdev_type_attr_show(struct kobject *kobj,
+				     struct attribute *__attr, char *buf)
+{
+	struct mdev_type_attribute *attr = to_mdev_type_attr(__attr);
+	struct mdev_type *type = to_mdev_type(kobj);
+	ssize_t ret = -EIO;
+
+	if (attr->show)
+		ret = attr->show(type, attr, buf);
+	return ret;
+}
+
+static ssize_t mdev_type_attr_store(struct kobject *kobj,
+				      struct attribute *__attr,
+				      const char *buf, size_t count)
+{
+	struct mdev_type_attribute *attr = to_mdev_type_attr(__attr);
+	struct mdev_type *type = to_mdev_type(kobj);
+	ssize_t ret = -EIO;
+
+	if (attr->store)
+		ret = attr->store(type, attr, buf, count);
+	return ret;
+}
+
+static const struct sysfs_ops mdev_type_sysfs_ops = {
+	.show = mdev_type_attr_show,
+	.store = mdev_type_attr_store,
+};
+
+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;
+	int ret;
+
+	if ((count < UUID_STRING_LEN) || (count > UUID_STRING_LEN + 1))
+		return -EINVAL;
+
+	str = kstrndup(buf, count, GFP_KERNEL);
+	if (!str)
+		return -ENOMEM;
+
+	ret = guid_parse(str, &uuid);
+	kfree(str);
+	if (ret)
+		return ret;
+
+	ret = mdev_device_create(mtype, &uuid);
+	if (ret)
+		return ret;
+
+	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 ssize_t name_show(struct mdev_type *mtype,
+			 struct mdev_type_attribute *attr, char *buf)
+{
+	return sysfs_emit(buf, "%s\n",
+		mtype->pretty_name ? mtype->pretty_name : mtype->sysfs_name);
+}
+
+static MDEV_TYPE_ATTR_RO(name);
+
+static ssize_t available_instances_show(struct mdev_type *mtype,
+					struct mdev_type_attribute *attr,
+					char *buf)
+{
+	struct mdev_driver *drv = mtype->parent->mdev_driver;
+
+	if (drv->get_available)
+		return sysfs_emit(buf, "%u\n", drv->get_available(mtype));
+	return sysfs_emit(buf, "%u\n",
+			  atomic_read(&mtype->parent->available_instances));
+}
+static MDEV_TYPE_ATTR_RO(available_instances);
+
+static ssize_t description_show(struct mdev_type *mtype,
+				struct mdev_type_attribute *attr,
+				char *buf)
+{
+	return mtype->parent->mdev_driver->show_description(mtype, buf);
+}
+static MDEV_TYPE_ATTR_RO(description);
+
+static struct attribute *mdev_types_core_attrs[] = {
+	&mdev_type_attr_create.attr,
+	&mdev_type_attr_device_api.attr,
+	&mdev_type_attr_name.attr,
+	&mdev_type_attr_available_instances.attr,
+	&mdev_type_attr_description.attr,
+	NULL,
+};
+
+static umode_t mdev_types_core_is_visible(struct kobject *kobj,
+					  struct attribute *attr, int n)
+{
+	if (attr == &mdev_type_attr_description.attr &&
+	    !to_mdev_type(kobj)->parent->mdev_driver->show_description)
+		return 0;
+	return attr->mode;
+}
+
+static struct attribute_group mdev_type_core_group = {
+	.attrs = mdev_types_core_attrs,
+	.is_visible = mdev_types_core_is_visible,
+};
+
+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);
+
+	pr_debug("Releasing group %s\n", kobj->name);
+	/* Pairs with the get in mdev_type_add() */
+	put_device(type->parent->dev);
+}
+
+static const struct kobj_type mdev_type_ktype = {
+	.sysfs_ops	= &mdev_type_sysfs_ops,
+	.release	= mdev_type_release,
+	.default_groups	= mdev_type_groups,
+};
+
+static int mdev_type_add(struct mdev_parent *parent, struct mdev_type *type)
+{
+	int ret;
+
+	type->kobj.kset = parent->mdev_types_kset;
+	type->parent = parent;
+	/* Pairs with the put in mdev_type_release() */
+	get_device(parent->dev);
+
+	ret = kobject_init_and_add(&type->kobj, &mdev_type_ktype, NULL,
+				   "%s-%s", dev_driver_string(parent->dev),
+				   type->sysfs_name);
+	if (ret) {
+		kobject_put(&type->kobj);
+		return ret;
+	}
+
+	type->devices_kobj = kobject_create_and_add("devices", &type->kobj);
+	if (!type->devices_kobj) {
+		ret = -ENOMEM;
+		goto attr_devices_failed;
+	}
+
+	return 0;
+
+attr_devices_failed:
+	kobject_del(&type->kobj);
+	kobject_put(&type->kobj);
+	return ret;
+}
+
+static void mdev_type_remove(struct mdev_type *type)
+{
+	kobject_put(type->devices_kobj);
+	kobject_del(&type->kobj);
+	kobject_put(&type->kobj);
+}
+
+/* mdev sysfs functions */
+void parent_remove_sysfs_files(struct mdev_parent *parent)
+{
+	int i;
+
+	for (i = 0; i < parent->nr_types; i++)
+		mdev_type_remove(parent->types[i]);
+	kset_unregister(parent->mdev_types_kset);
+}
+
+int parent_create_sysfs_files(struct mdev_parent *parent)
+{
+	int ret, i;
+
+	parent->mdev_types_kset = kset_create_and_add("mdev_supported_types",
+					       NULL, &parent->dev->kobj);
+	if (!parent->mdev_types_kset)
+		return -ENOMEM;
+
+	for (i = 0; i < parent->nr_types; i++) {
+		ret = mdev_type_add(parent, parent->types[i]);
+		if (ret)
+			goto out_err;
+	}
+	return 0;
+
+out_err:
+	while (--i >= 0)
+		mdev_type_remove(parent->types[i]);
+	kset_unregister(parent->mdev_types_kset);
+	return ret;
+}
+
+static ssize_t remove_store(struct device *dev, struct device_attribute *attr,
+			    const char *buf, size_t count)
+{
+	struct mdev_device *mdev = to_mdev_device(dev);
+	unsigned long val;
+
+	if (kstrtoul(buf, 0, &val) < 0)
+		return -EINVAL;
+
+	if (val && device_remove_file_self(dev, attr)) {
+		int ret;
+
+		ret = mdev_device_remove(mdev);
+		if (ret)
+			return ret;
+	}
+
+	return count;
+}
+
+static DEVICE_ATTR_WO(remove);
+
+static struct attribute *mdev_device_attrs[] = {
+	&dev_attr_remove.attr,
+	NULL,
+};
+
+static const struct attribute_group mdev_device_group = {
+	.attrs = mdev_device_attrs,
+};
+
+const struct attribute_group *mdev_device_groups[] = {
+	&mdev_device_group,
+	NULL
+};
+
+int mdev_create_sysfs_files(struct mdev_device *mdev)
+{
+	struct mdev_type *type = mdev->type;
+	struct kobject *kobj = &mdev->dev.kobj;
+	int ret;
+
+	ret = sysfs_create_link(type->devices_kobj, kobj, dev_name(&mdev->dev));
+	if (ret)
+		return ret;
+
+	ret = sysfs_create_link(kobj, &type->kobj, "mdev_type");
+	if (ret)
+		goto type_link_failed;
+	return ret;
+
+type_link_failed:
+	sysfs_remove_link(mdev->type->devices_kobj, dev_name(&mdev->dev));
+	return ret;
+}
+
+void mdev_remove_sysfs_files(struct mdev_device *mdev)
+{
+	struct kobject *kobj = &mdev->dev.kobj;
+
+	sysfs_remove_link(kobj, "mdev_type");
+	sysfs_remove_link(mdev->type->devices_kobj, dev_name(&mdev->dev));
+}