Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 915 insertions, 0 deletions

diff --git a/drivers/media/mc/mc-device.c b/drivers/media/mc/mc-device.c
new file mode 100644
index 000000000..f8ea7cfe1
--- /dev/null
+++ b/drivers/media/mc/mc-device.c
@@ -0,0 +1,915 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Media device
+ *
+ * Copyright (C) 2010 Nokia Corporation
+ *
+ * Contacts: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
+ *	     Sakari Ailus <sakari.ailus@iki.fi>
+ */
+
+#include <linux/compat.h>
+#include <linux/export.h>
+#include <linux/idr.h>
+#include <linux/ioctl.h>
+#include <linux/media.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/pci.h>
+#include <linux/usb.h>
+#include <linux/version.h>
+
+#include <media/media-device.h>
+#include <media/media-devnode.h>
+#include <media/media-entity.h>
+#include <media/media-request.h>
+
+#ifdef CONFIG_MEDIA_CONTROLLER
+
+/*
+ * Legacy defines from linux/media.h. This is the only place we need this
+ * so we just define it here. The media.h header doesn't expose it to the
+ * kernel to prevent it from being used by drivers, but here (and only here!)
+ * we need it to handle the legacy behavior.
+ */
+#define MEDIA_ENT_SUBTYPE_MASK			0x0000ffff
+#define MEDIA_ENT_T_DEVNODE_UNKNOWN		(MEDIA_ENT_F_OLD_BASE | \
+						 MEDIA_ENT_SUBTYPE_MASK)
+
+/* -----------------------------------------------------------------------------
+ * Userspace API
+ */
+
+static inline void __user *media_get_uptr(__u64 arg)
+{
+	return (void __user *)(uintptr_t)arg;
+}
+
+static int media_device_open(struct file *filp)
+{
+	return 0;
+}
+
+static int media_device_close(struct file *filp)
+{
+	return 0;
+}
+
+static long media_device_get_info(struct media_device *dev, void *arg)
+{
+	struct media_device_info *info = arg;
+
+	memset(info, 0, sizeof(*info));
+
+	if (dev->driver_name[0])
+		strscpy(info->driver, dev->driver_name, sizeof(info->driver));
+	else
+		strscpy(info->driver, dev->dev->driver->name,
+			sizeof(info->driver));
+
+	strscpy(info->model, dev->model, sizeof(info->model));
+	strscpy(info->serial, dev->serial, sizeof(info->serial));
+	strscpy(info->bus_info, dev->bus_info, sizeof(info->bus_info));
+
+	info->media_version = LINUX_VERSION_CODE;
+	info->driver_version = info->media_version;
+	info->hw_revision = dev->hw_revision;
+
+	return 0;
+}
+
+static struct media_entity *find_entity(struct media_device *mdev, u32 id)
+{
+	struct media_entity *entity;
+	int next = id & MEDIA_ENT_ID_FLAG_NEXT;
+
+	id &= ~MEDIA_ENT_ID_FLAG_NEXT;
+
+	media_device_for_each_entity(entity, mdev) {
+		if (((media_entity_id(entity) == id) && !next) ||
+		    ((media_entity_id(entity) > id) && next)) {
+			return entity;
+		}
+	}
+
+	return NULL;
+}
+
+static long media_device_enum_entities(struct media_device *mdev, void *arg)
+{
+	struct media_entity_desc *entd = arg;
+	struct media_entity *ent;
+
+	ent = find_entity(mdev, entd->id);
+	if (ent == NULL)
+		return -EINVAL;
+
+	memset(entd, 0, sizeof(*entd));
+
+	entd->id = media_entity_id(ent);
+	if (ent->name)
+		strscpy(entd->name, ent->name, sizeof(entd->name));
+	entd->type = ent->function;
+	entd->revision = 0;		/* Unused */
+	entd->flags = ent->flags;
+	entd->group_id = 0;		/* Unused */
+	entd->pads = ent->num_pads;
+	entd->links = ent->num_links - ent->num_backlinks;
+
+	/*
+	 * Workaround for a bug at media-ctl <= v1.10 that makes it to
+	 * do the wrong thing if the entity function doesn't belong to
+	 * either MEDIA_ENT_F_OLD_BASE or MEDIA_ENT_F_OLD_SUBDEV_BASE
+	 * Ranges.
+	 *
+	 * Non-subdevices are expected to be at the MEDIA_ENT_F_OLD_BASE,
+	 * or, otherwise, will be silently ignored by media-ctl when
+	 * printing the graphviz diagram. So, map them into the devnode
+	 * old range.
+	 */
+	if (ent->function < MEDIA_ENT_F_OLD_BASE ||
+	    ent->function > MEDIA_ENT_F_TUNER) {
+		if (is_media_entity_v4l2_subdev(ent))
+			entd->type = MEDIA_ENT_F_V4L2_SUBDEV_UNKNOWN;
+		else if (ent->function != MEDIA_ENT_F_IO_V4L)
+			entd->type = MEDIA_ENT_T_DEVNODE_UNKNOWN;
+	}
+
+	memcpy(&entd->raw, &ent->info, sizeof(ent->info));
+
+	return 0;
+}
+
+static void media_device_kpad_to_upad(const struct media_pad *kpad,
+				      struct media_pad_desc *upad)
+{
+	upad->entity = media_entity_id(kpad->entity);
+	upad->index = kpad->index;
+	upad->flags = kpad->flags;
+}
+
+static long media_device_enum_links(struct media_device *mdev, void *arg)
+{
+	struct media_links_enum *links = arg;
+	struct media_entity *entity;
+
+	entity = find_entity(mdev, links->entity);
+	if (entity == NULL)
+		return -EINVAL;
+
+	if (links->pads) {
+		unsigned int p;
+
+		for (p = 0; p < entity->num_pads; p++) {
+			struct media_pad_desc pad;
+
+			memset(&pad, 0, sizeof(pad));
+			media_device_kpad_to_upad(&entity->pads[p], &pad);
+			if (copy_to_user(&links->pads[p], &pad, sizeof(pad)))
+				return -EFAULT;
+		}
+	}
+
+	if (links->links) {
+		struct media_link *link;
+		struct media_link_desc __user *ulink_desc = links->links;
+
+		list_for_each_entry(link, &entity->links, list) {
+			struct media_link_desc klink_desc;
+
+			/* Ignore backlinks. */
+			if (link->source->entity != entity)
+				continue;
+			memset(&klink_desc, 0, sizeof(klink_desc));
+			media_device_kpad_to_upad(link->source,
+						  &klink_desc.source);
+			media_device_kpad_to_upad(link->sink,
+						  &klink_desc.sink);
+			klink_desc.flags = link->flags;
+			if (copy_to_user(ulink_desc, &klink_desc,
+					 sizeof(*ulink_desc)))
+				return -EFAULT;
+			ulink_desc++;
+		}
+	}
+	memset(links->reserved, 0, sizeof(links->reserved));
+
+	return 0;
+}
+
+static long media_device_setup_link(struct media_device *mdev, void *arg)
+{
+	struct media_link_desc *linkd = arg;
+	struct media_link *link = NULL;
+	struct media_entity *source;
+	struct media_entity *sink;
+
+	/* Find the source and sink entities and link.
+	 */
+	source = find_entity(mdev, linkd->source.entity);
+	sink = find_entity(mdev, linkd->sink.entity);
+
+	if (source == NULL || sink == NULL)
+		return -EINVAL;
+
+	if (linkd->source.index >= source->num_pads ||
+	    linkd->sink.index >= sink->num_pads)
+		return -EINVAL;
+
+	link = media_entity_find_link(&source->pads[linkd->source.index],
+				      &sink->pads[linkd->sink.index]);
+	if (link == NULL)
+		return -EINVAL;
+
+	memset(linkd->reserved, 0, sizeof(linkd->reserved));
+
+	/* Setup the link on both entities. */
+	return __media_entity_setup_link(link, linkd->flags);
+}
+
+static long media_device_get_topology(struct media_device *mdev, void *arg)
+{
+	struct media_v2_topology *topo = arg;
+	struct media_entity *entity;
+	struct media_interface *intf;
+	struct media_pad *pad;
+	struct media_link *link;
+	struct media_v2_entity kentity, __user *uentity;
+	struct media_v2_interface kintf, __user *uintf;
+	struct media_v2_pad kpad, __user *upad;
+	struct media_v2_link klink, __user *ulink;
+	unsigned int i;
+	int ret = 0;
+
+	topo->topology_version = mdev->topology_version;
+
+	/* Get entities and number of entities */
+	i = 0;
+	uentity = media_get_uptr(topo->ptr_entities);
+	media_device_for_each_entity(entity, mdev) {
+		i++;
+		if (ret || !uentity)
+			continue;
+
+		if (i > topo->num_entities) {
+			ret = -ENOSPC;
+			continue;
+		}
+
+		/* Copy fields to userspace struct if not error */
+		memset(&kentity, 0, sizeof(kentity));
+		kentity.id = entity->graph_obj.id;
+		kentity.function = entity->function;
+		kentity.flags = entity->flags;
+		strscpy(kentity.name, entity->name,
+			sizeof(kentity.name));
+
+		if (copy_to_user(uentity, &kentity, sizeof(kentity)))
+			ret = -EFAULT;
+		uentity++;
+	}
+	topo->num_entities = i;
+	topo->reserved1 = 0;
+
+	/* Get interfaces and number of interfaces */
+	i = 0;
+	uintf = media_get_uptr(topo->ptr_interfaces);
+	media_device_for_each_intf(intf, mdev) {
+		i++;
+		if (ret || !uintf)
+			continue;
+
+		if (i > topo->num_interfaces) {
+			ret = -ENOSPC;
+			continue;
+		}
+
+		memset(&kintf, 0, sizeof(kintf));
+
+		/* Copy intf fields to userspace struct */
+		kintf.id = intf->graph_obj.id;
+		kintf.intf_type = intf->type;
+		kintf.flags = intf->flags;
+
+		if (media_type(&intf->graph_obj) == MEDIA_GRAPH_INTF_DEVNODE) {
+			struct media_intf_devnode *devnode;
+
+			devnode = intf_to_devnode(intf);
+
+			kintf.devnode.major = devnode->major;
+			kintf.devnode.minor = devnode->minor;
+		}
+
+		if (copy_to_user(uintf, &kintf, sizeof(kintf)))
+			ret = -EFAULT;
+		uintf++;
+	}
+	topo->num_interfaces = i;
+	topo->reserved2 = 0;
+
+	/* Get pads and number of pads */
+	i = 0;
+	upad = media_get_uptr(topo->ptr_pads);
+	media_device_for_each_pad(pad, mdev) {
+		i++;
+		if (ret || !upad)
+			continue;
+
+		if (i > topo->num_pads) {
+			ret = -ENOSPC;
+			continue;
+		}
+
+		memset(&kpad, 0, sizeof(kpad));
+
+		/* Copy pad fields to userspace struct */
+		kpad.id = pad->graph_obj.id;
+		kpad.entity_id = pad->entity->graph_obj.id;
+		kpad.flags = pad->flags;
+		kpad.index = pad->index;
+
+		if (copy_to_user(upad, &kpad, sizeof(kpad)))
+			ret = -EFAULT;
+		upad++;
+	}
+	topo->num_pads = i;
+	topo->reserved3 = 0;
+
+	/* Get links and number of links */
+	i = 0;
+	ulink = media_get_uptr(topo->ptr_links);
+	media_device_for_each_link(link, mdev) {
+		if (link->is_backlink)
+			continue;
+
+		i++;
+
+		if (ret || !ulink)
+			continue;
+
+		if (i > topo->num_links) {
+			ret = -ENOSPC;
+			continue;
+		}
+
+		memset(&klink, 0, sizeof(klink));
+
+		/* Copy link fields to userspace struct */
+		klink.id = link->graph_obj.id;
+		klink.source_id = link->gobj0->id;
+		klink.sink_id = link->gobj1->id;
+		klink.flags = link->flags;
+
+		if (copy_to_user(ulink, &klink, sizeof(klink)))
+			ret = -EFAULT;
+		ulink++;
+	}
+	topo->num_links = i;
+	topo->reserved4 = 0;
+
+	return ret;
+}
+
+static long media_device_request_alloc(struct media_device *mdev, void *arg)
+{
+	int *alloc_fd = arg;
+
+	if (!mdev->ops || !mdev->ops->req_validate || !mdev->ops->req_queue)
+		return -ENOTTY;
+
+	return media_request_alloc(mdev, alloc_fd);
+}
+
+static long copy_arg_from_user(void *karg, void __user *uarg, unsigned int cmd)
+{
+	if ((_IOC_DIR(cmd) & _IOC_WRITE) &&
+	    copy_from_user(karg, uarg, _IOC_SIZE(cmd)))
+		return -EFAULT;
+
+	return 0;
+}
+
+static long copy_arg_to_user(void __user *uarg, void *karg, unsigned int cmd)
+{
+	if ((_IOC_DIR(cmd) & _IOC_READ) &&
+	    copy_to_user(uarg, karg, _IOC_SIZE(cmd)))
+		return -EFAULT;
+
+	return 0;
+}
+
+/* Do acquire the graph mutex */
+#define MEDIA_IOC_FL_GRAPH_MUTEX	BIT(0)
+
+#define MEDIA_IOC_ARG(__cmd, func, fl, from_user, to_user)		\
+	[_IOC_NR(MEDIA_IOC_##__cmd)] = {				\
+		.cmd = MEDIA_IOC_##__cmd,				\
+		.fn = func,						\
+		.flags = fl,						\
+		.arg_from_user = from_user,				\
+		.arg_to_user = to_user,					\
+	}
+
+#define MEDIA_IOC(__cmd, func, fl)					\
+	MEDIA_IOC_ARG(__cmd, func, fl, copy_arg_from_user, copy_arg_to_user)
+
+/* the table is indexed by _IOC_NR(cmd) */
+struct media_ioctl_info {
+	unsigned int cmd;
+	unsigned short flags;
+	long (*fn)(struct media_device *dev, void *arg);
+	long (*arg_from_user)(void *karg, void __user *uarg, unsigned int cmd);
+	long (*arg_to_user)(void __user *uarg, void *karg, unsigned int cmd);
+};
+
+static const struct media_ioctl_info ioctl_info[] = {
+	MEDIA_IOC(DEVICE_INFO, media_device_get_info, MEDIA_IOC_FL_GRAPH_MUTEX),
+	MEDIA_IOC(ENUM_ENTITIES, media_device_enum_entities, MEDIA_IOC_FL_GRAPH_MUTEX),
+	MEDIA_IOC(ENUM_LINKS, media_device_enum_links, MEDIA_IOC_FL_GRAPH_MUTEX),
+	MEDIA_IOC(SETUP_LINK, media_device_setup_link, MEDIA_IOC_FL_GRAPH_MUTEX),
+	MEDIA_IOC(G_TOPOLOGY, media_device_get_topology, MEDIA_IOC_FL_GRAPH_MUTEX),
+	MEDIA_IOC(REQUEST_ALLOC, media_device_request_alloc, 0),
+};
+
+static long media_device_ioctl(struct file *filp, unsigned int cmd,
+			       unsigned long __arg)
+{
+	struct media_devnode *devnode = media_devnode_data(filp);
+	struct media_device *dev = devnode->media_dev;
+	const struct media_ioctl_info *info;
+	void __user *arg = (void __user *)__arg;
+	char __karg[256], *karg = __karg;
+	long ret;
+
+	if (_IOC_NR(cmd) >= ARRAY_SIZE(ioctl_info)
+	    || ioctl_info[_IOC_NR(cmd)].cmd != cmd)
+		return -ENOIOCTLCMD;
+
+	info = &ioctl_info[_IOC_NR(cmd)];
+
+	if (_IOC_SIZE(info->cmd) > sizeof(__karg)) {
+		karg = kmalloc(_IOC_SIZE(info->cmd), GFP_KERNEL);
+		if (!karg)
+			return -ENOMEM;
+	}
+
+	if (info->arg_from_user) {
+		ret = info->arg_from_user(karg, arg, cmd);
+		if (ret)
+			goto out_free;
+	}
+
+	if (info->flags & MEDIA_IOC_FL_GRAPH_MUTEX)
+		mutex_lock(&dev->graph_mutex);
+
+	ret = info->fn(dev, karg);
+
+	if (info->flags & MEDIA_IOC_FL_GRAPH_MUTEX)
+		mutex_unlock(&dev->graph_mutex);
+
+	if (!ret && info->arg_to_user)
+		ret = info->arg_to_user(arg, karg, cmd);
+
+out_free:
+	if (karg != __karg)
+		kfree(karg);
+
+	return ret;
+}
+
+#ifdef CONFIG_COMPAT
+
+struct media_links_enum32 {
+	__u32 entity;
+	compat_uptr_t pads; /* struct media_pad_desc * */
+	compat_uptr_t links; /* struct media_link_desc * */
+	__u32 reserved[4];
+};
+
+static long media_device_enum_links32(struct media_device *mdev,
+				      struct media_links_enum32 __user *ulinks)
+{
+	struct media_links_enum links;
+	compat_uptr_t pads_ptr, links_ptr;
+	int ret;
+
+	memset(&links, 0, sizeof(links));
+
+	if (get_user(links.entity, &ulinks->entity)
+	    || get_user(pads_ptr, &ulinks->pads)
+	    || get_user(links_ptr, &ulinks->links))
+		return -EFAULT;
+
+	links.pads = compat_ptr(pads_ptr);
+	links.links = compat_ptr(links_ptr);
+
+	ret = media_device_enum_links(mdev, &links);
+	if (ret)
+		return ret;
+
+	if (copy_to_user(ulinks->reserved, links.reserved,
+			 sizeof(ulinks->reserved)))
+		return -EFAULT;
+	return 0;
+}
+
+#define MEDIA_IOC_ENUM_LINKS32		_IOWR('|', 0x02, struct media_links_enum32)
+
+static long media_device_compat_ioctl(struct file *filp, unsigned int cmd,
+				      unsigned long arg)
+{
+	struct media_devnode *devnode = media_devnode_data(filp);
+	struct media_device *dev = devnode->media_dev;
+	long ret;
+
+	switch (cmd) {
+	case MEDIA_IOC_ENUM_LINKS32:
+		mutex_lock(&dev->graph_mutex);
+		ret = media_device_enum_links32(dev,
+				(struct media_links_enum32 __user *)arg);
+		mutex_unlock(&dev->graph_mutex);
+		break;
+
+	default:
+		return media_device_ioctl(filp, cmd, arg);
+	}
+
+	return ret;
+}
+#endif /* CONFIG_COMPAT */
+
+static const struct media_file_operations media_device_fops = {
+	.owner = THIS_MODULE,
+	.open = media_device_open,
+	.ioctl = media_device_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl = media_device_compat_ioctl,
+#endif /* CONFIG_COMPAT */
+	.release = media_device_close,
+};
+
+/* -----------------------------------------------------------------------------
+ * sysfs
+ */
+
+static ssize_t model_show(struct device *cd,
+			  struct device_attribute *attr, char *buf)
+{
+	struct media_devnode *devnode = to_media_devnode(cd);
+	struct media_device *mdev = devnode->media_dev;
+
+	return sprintf(buf, "%.*s\n", (int)sizeof(mdev->model), mdev->model);
+}
+
+static DEVICE_ATTR_RO(model);
+
+/* -----------------------------------------------------------------------------
+ * Registration/unregistration
+ */
+
+static void media_device_release(struct media_devnode *devnode)
+{
+	dev_dbg(devnode->parent, "Media device released\n");
+}
+
+static void __media_device_unregister_entity(struct media_entity *entity)
+{
+	struct media_device *mdev = entity->graph_obj.mdev;
+	struct media_link *link, *tmp;
+	struct media_interface *intf;
+	struct media_pad *iter;
+
+	ida_free(&mdev->entity_internal_idx, entity->internal_idx);
+
+	/* Remove all interface links pointing to this entity */
+	list_for_each_entry(intf, &mdev->interfaces, graph_obj.list) {
+		list_for_each_entry_safe(link, tmp, &intf->links, list) {
+			if (link->entity == entity)
+				__media_remove_intf_link(link);
+		}
+	}
+
+	/* Remove all data links that belong to this entity */
+	__media_entity_remove_links(entity);
+
+	/* Remove all pads that belong to this entity */
+	media_entity_for_each_pad(entity, iter)
+		media_gobj_destroy(&iter->graph_obj);
+
+	/* Remove the entity */
+	media_gobj_destroy(&entity->graph_obj);
+
+	/* invoke entity_notify callbacks to handle entity removal?? */
+}
+
+int __must_check media_device_register_entity(struct media_device *mdev,
+					      struct media_entity *entity)
+{
+	struct media_entity_notify *notify, *next;
+	struct media_pad *iter;
+	int ret;
+
+	if (entity->function == MEDIA_ENT_F_V4L2_SUBDEV_UNKNOWN ||
+	    entity->function == MEDIA_ENT_F_UNKNOWN)
+		dev_warn(mdev->dev,
+			 "Entity type for entity %s was not initialized!\n",
+			 entity->name);
+
+	/* Warn if we apparently re-register an entity */
+	WARN_ON(entity->graph_obj.mdev != NULL);
+	entity->graph_obj.mdev = mdev;
+	INIT_LIST_HEAD(&entity->links);
+	entity->num_links = 0;
+	entity->num_backlinks = 0;
+
+	ret = ida_alloc_min(&mdev->entity_internal_idx, 1, GFP_KERNEL);
+	if (ret < 0)
+		return ret;
+	entity->internal_idx = ret;
+
+	mutex_lock(&mdev->graph_mutex);
+	mdev->entity_internal_idx_max =
+		max(mdev->entity_internal_idx_max, entity->internal_idx);
+
+	/* Initialize media_gobj embedded at the entity */
+	media_gobj_create(mdev, MEDIA_GRAPH_ENTITY, &entity->graph_obj);
+
+	/* Initialize objects at the pads */
+	media_entity_for_each_pad(entity, iter)
+		media_gobj_create(mdev, MEDIA_GRAPH_PAD, &iter->graph_obj);
+
+	/* invoke entity_notify callbacks */
+	list_for_each_entry_safe(notify, next, &mdev->entity_notify, list)
+		notify->notify(entity, notify->notify_data);
+
+	if (mdev->entity_internal_idx_max
+	    >= mdev->pm_count_walk.ent_enum.idx_max) {
+		struct media_graph new = { .top = 0 };
+
+		/*
+		 * Initialise the new graph walk before cleaning up
+		 * the old one in order not to spoil the graph walk
+		 * object of the media device if graph walk init fails.
+		 */
+		ret = media_graph_walk_init(&new, mdev);
+		if (ret) {
+			__media_device_unregister_entity(entity);
+			mutex_unlock(&mdev->graph_mutex);
+			return ret;
+		}
+		media_graph_walk_cleanup(&mdev->pm_count_walk);
+		mdev->pm_count_walk = new;
+	}
+	mutex_unlock(&mdev->graph_mutex);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(media_device_register_entity);
+
+void media_device_unregister_entity(struct media_entity *entity)
+{
+	struct media_device *mdev = entity->graph_obj.mdev;
+
+	if (mdev == NULL)
+		return;
+
+	mutex_lock(&mdev->graph_mutex);
+	__media_device_unregister_entity(entity);
+	mutex_unlock(&mdev->graph_mutex);
+}
+EXPORT_SYMBOL_GPL(media_device_unregister_entity);
+
+#ifdef CONFIG_DEBUG_FS
+/*
+ * Log the state of media requests. Very useful for debugging.
+ */
+static int media_device_requests(struct seq_file *file, void *priv)
+{
+	struct media_device *dev = dev_get_drvdata(file->private);
+
+	seq_printf(file, "number of requests: %d\n",
+		   atomic_read(&dev->num_requests));
+	seq_printf(file, "number of request objects: %d\n",
+		   atomic_read(&dev->num_request_objects));
+
+	return 0;
+}
+#endif
+
+void media_device_init(struct media_device *mdev)
+{
+	INIT_LIST_HEAD(&mdev->entities);
+	INIT_LIST_HEAD(&mdev->interfaces);
+	INIT_LIST_HEAD(&mdev->pads);
+	INIT_LIST_HEAD(&mdev->links);
+	INIT_LIST_HEAD(&mdev->entity_notify);
+
+	mutex_init(&mdev->req_queue_mutex);
+	mutex_init(&mdev->graph_mutex);
+	ida_init(&mdev->entity_internal_idx);
+
+	atomic_set(&mdev->request_id, 0);
+
+	if (!*mdev->bus_info)
+		media_set_bus_info(mdev->bus_info, sizeof(mdev->bus_info),
+				   mdev->dev);
+
+	atomic_set(&mdev->num_requests, 0);
+	atomic_set(&mdev->num_request_objects, 0);
+
+	dev_dbg(mdev->dev, "Media device initialized\n");
+}
+EXPORT_SYMBOL_GPL(media_device_init);
+
+void media_device_cleanup(struct media_device *mdev)
+{
+	ida_destroy(&mdev->entity_internal_idx);
+	mdev->entity_internal_idx_max = 0;
+	media_graph_walk_cleanup(&mdev->pm_count_walk);
+	mutex_destroy(&mdev->graph_mutex);
+	mutex_destroy(&mdev->req_queue_mutex);
+}
+EXPORT_SYMBOL_GPL(media_device_cleanup);
+
+int __must_check __media_device_register(struct media_device *mdev,
+					 struct module *owner)
+{
+	struct media_devnode *devnode;
+	int ret;
+
+	devnode = kzalloc_obj(*devnode);
+	if (!devnode)
+		return -ENOMEM;
+
+	/* Register the device node. */
+	mdev->devnode = devnode;
+	devnode->fops = &media_device_fops;
+	devnode->parent = mdev->dev;
+	devnode->release = media_device_release;
+
+	/* Set version 0 to indicate user-space that the graph is static */
+	mdev->topology_version = 0;
+
+	ret = media_devnode_register(mdev, devnode, owner);
+	if (ret < 0) {
+		/* devnode free is handled in media_devnode_*() */
+		mdev->devnode = NULL;
+		return ret;
+	}
+
+	ret = device_create_file(&devnode->dev, &dev_attr_model);
+	if (ret < 0) {
+		/* devnode free is handled in media_devnode_*() */
+		mdev->devnode = NULL;
+		media_devnode_unregister_prepare(devnode);
+		media_devnode_unregister(devnode);
+		return ret;
+	}
+
+	dev_dbg(mdev->dev, "Media device registered\n");
+
+#ifdef CONFIG_DEBUG_FS
+	if (!media_debugfs_root)
+		media_debugfs_root = debugfs_create_dir("media", NULL);
+	mdev->media_dir = debugfs_create_dir(dev_name(&devnode->dev),
+					     media_debugfs_root);
+	debugfs_create_devm_seqfile(&devnode->dev, "requests",
+				    mdev->media_dir, media_device_requests);
+#endif
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(__media_device_register);
+
+void media_device_register_entity_notify(struct media_device *mdev,
+					struct media_entity_notify *nptr)
+{
+	mutex_lock(&mdev->graph_mutex);
+	list_add_tail(&nptr->list, &mdev->entity_notify);
+	mutex_unlock(&mdev->graph_mutex);
+}
+EXPORT_SYMBOL_GPL(media_device_register_entity_notify);
+
+/*
+ * Note: Should be called with mdev->lock held.
+ */
+static void __media_device_unregister_entity_notify(struct media_device *mdev,
+					struct media_entity_notify *nptr)
+{
+	list_del(&nptr->list);
+}
+
+void media_device_unregister_entity_notify(struct media_device *mdev,
+					struct media_entity_notify *nptr)
+{
+	mutex_lock(&mdev->graph_mutex);
+	__media_device_unregister_entity_notify(mdev, nptr);
+	mutex_unlock(&mdev->graph_mutex);
+}
+EXPORT_SYMBOL_GPL(media_device_unregister_entity_notify);
+
+void media_device_unregister(struct media_device *mdev)
+{
+	struct media_entity *entity;
+	struct media_entity *next;
+	struct media_interface *intf, *tmp_intf;
+	struct media_entity_notify *notify, *nextp;
+
+	if (mdev == NULL)
+		return;
+
+	mutex_lock(&mdev->graph_mutex);
+
+	/* Check if mdev was ever registered at all */
+	if (!media_devnode_is_registered(mdev->devnode)) {
+		mutex_unlock(&mdev->graph_mutex);
+		return;
+	}
+
+	/* Clear the devnode register bit to avoid races with media dev open */
+	media_devnode_unregister_prepare(mdev->devnode);
+
+	/* Remove all entities from the media device */
+	list_for_each_entry_safe(entity, next, &mdev->entities, graph_obj.list)
+		__media_device_unregister_entity(entity);
+
+	/* Remove all entity_notify callbacks from the media device */
+	list_for_each_entry_safe(notify, nextp, &mdev->entity_notify, list)
+		__media_device_unregister_entity_notify(mdev, notify);
+
+	/* Remove all interfaces from the media device */
+	list_for_each_entry_safe(intf, tmp_intf, &mdev->interfaces,
+				 graph_obj.list) {
+		/*
+		 * Unlink the interface, but don't free it here; the
+		 * module which created it is responsible for freeing
+		 * it
+		 */
+		__media_remove_intf_links(intf);
+		media_gobj_destroy(&intf->graph_obj);
+	}
+
+	mutex_unlock(&mdev->graph_mutex);
+
+	dev_dbg(mdev->dev, "Media device unregistered\n");
+
+	debugfs_remove_recursive(mdev->media_dir);
+	device_remove_file(&mdev->devnode->dev, &dev_attr_model);
+	media_devnode_unregister(mdev->devnode);
+	/* devnode free is handled in media_devnode_*() */
+	mdev->devnode = NULL;
+}
+EXPORT_SYMBOL_GPL(media_device_unregister);
+
+#if IS_ENABLED(CONFIG_PCI)
+void media_device_pci_init(struct media_device *mdev,
+			   struct pci_dev *pci_dev,
+			   const char *name)
+{
+	mdev->dev = &pci_dev->dev;
+
+	if (name)
+		strscpy(mdev->model, name, sizeof(mdev->model));
+	else
+		strscpy(mdev->model, pci_name(pci_dev), sizeof(mdev->model));
+
+	sprintf(mdev->bus_info, "PCI:%s", pci_name(pci_dev));
+
+	mdev->hw_revision = (pci_dev->subsystem_vendor << 16)
+			    | pci_dev->subsystem_device;
+
+	media_device_init(mdev);
+}
+EXPORT_SYMBOL_GPL(media_device_pci_init);
+#endif
+
+#if IS_ENABLED(CONFIG_USB)
+void __media_device_usb_init(struct media_device *mdev,
+			     struct usb_device *udev,
+			     const char *board_name,
+			     const char *driver_name)
+{
+	mdev->dev = &udev->dev;
+
+	if (driver_name)
+		strscpy(mdev->driver_name, driver_name,
+			sizeof(mdev->driver_name));
+
+	if (board_name)
+		strscpy(mdev->model, board_name, sizeof(mdev->model));
+	else if (udev->product)
+		strscpy(mdev->model, udev->product, sizeof(mdev->model));
+	else
+		strscpy(mdev->model, "unknown model", sizeof(mdev->model));
+	if (udev->serial)
+		strscpy(mdev->serial, udev->serial, sizeof(mdev->serial));
+	usb_make_path(udev, mdev->bus_info, sizeof(mdev->bus_info));
+	mdev->hw_revision = le16_to_cpu(udev->descriptor.bcdDevice);
+
+	media_device_init(mdev);
+}
+EXPORT_SYMBOL_GPL(__media_device_usb_init);
+#endif
+
+
+#endif /* CONFIG_MEDIA_CONTROLLER */