drm: Extract drm_property.[hc]

This just contains the base property classes and all the code to
handle blobs. I think for any kind of standardized/shared properties
it's better to have separate files - this is fairly big already as-is.

v2: resurrect misplaced hunk (Daniel Stone)

Cc: Daniel Stone <daniel@fooishbar.org>
Reviewed-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20160829082757.17913-7-daniel.vetter@ffwll.ch

1 files changed, 953 insertions, 0 deletions

diff --git a/drivers/gpu/drm/drm_property.c b/drivers/gpu/drm/drm_property.c
new file mode 100644
index 000000000000..162cc9032ae5
--- /dev/null
+++ b/drivers/gpu/drm/drm_property.c
@@ -0,0 +1,953 @@
+/*
+ * Copyright (c) 2016 Intel Corporation
+ *
+ * Permission to use, copy, modify, distribute, and sell this software and its
+ * documentation for any purpose is hereby granted without fee, provided that
+ * the above copyright notice appear in all copies and that both that copyright
+ * notice and this permission notice appear in supporting documentation, and
+ * that the name of the copyright holders not be used in advertising or
+ * publicity pertaining to distribution of the software without specific,
+ * written prior permission.  The copyright holders make no representations
+ * about the suitability of this software for any purpose.  It is provided "as
+ * is" without express or implied warranty.
+ *
+ * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
+ * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
+ * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
+ * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
+ * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
+ * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
+ * OF THIS SOFTWARE.
+ */
+
+#include <linux/export.h>
+#include <drm/drmP.h>
+#include <drm/drm_property.h>
+
+#include "drm_crtc_internal.h"
+
+static bool drm_property_type_valid(struct drm_property *property)
+{
+	if (property->flags & DRM_MODE_PROP_EXTENDED_TYPE)
+		return !(property->flags & DRM_MODE_PROP_LEGACY_TYPE);
+	return !!(property->flags & DRM_MODE_PROP_LEGACY_TYPE);
+}
+
+/**
+ * drm_property_create - create a new property type
+ * @dev: drm device
+ * @flags: flags specifying the property type
+ * @name: name of the property
+ * @num_values: number of pre-defined values
+ *
+ * This creates a new generic drm property which can then be attached to a drm
+ * object with drm_object_attach_property. The returned property object must be
+ * freed with drm_property_destroy.
+ *
+ * Note that the DRM core keeps a per-device list of properties and that, if
+ * drm_mode_config_cleanup() is called, it will destroy all properties created
+ * by the driver.
+ *
+ * Returns:
+ * A pointer to the newly created property on success, NULL on failure.
+ */
+struct drm_property *drm_property_create(struct drm_device *dev, int flags,
+					 const char *name, int num_values)
+{
+	struct drm_property *property = NULL;
+	int ret;
+
+	property = kzalloc(sizeof(struct drm_property), GFP_KERNEL);
+	if (!property)
+		return NULL;
+
+	property->dev = dev;
+
+	if (num_values) {
+		property->values = kcalloc(num_values, sizeof(uint64_t),
+					   GFP_KERNEL);
+		if (!property->values)
+			goto fail;
+	}
+
+	ret = drm_mode_object_get(dev, &property->base, DRM_MODE_OBJECT_PROPERTY);
+	if (ret)
+		goto fail;
+
+	property->flags = flags;
+	property->num_values = num_values;
+	INIT_LIST_HEAD(&property->enum_list);
+
+	if (name) {
+		strncpy(property->name, name, DRM_PROP_NAME_LEN);
+		property->name[DRM_PROP_NAME_LEN-1] = '\0';
+	}
+
+	list_add_tail(&property->head, &dev->mode_config.property_list);
+
+	WARN_ON(!drm_property_type_valid(property));
+
+	return property;
+fail:
+	kfree(property->values);
+	kfree(property);
+	return NULL;
+}
+EXPORT_SYMBOL(drm_property_create);
+
+/**
+ * drm_property_create_enum - create a new enumeration property type
+ * @dev: drm device
+ * @flags: flags specifying the property type
+ * @name: name of the property
+ * @props: enumeration lists with property values
+ * @num_values: number of pre-defined values
+ *
+ * This creates a new generic drm property which can then be attached to a drm
+ * object with drm_object_attach_property. The returned property object must be
+ * freed with drm_property_destroy.
+ *
+ * Userspace is only allowed to set one of the predefined values for enumeration
+ * properties.
+ *
+ * Returns:
+ * A pointer to the newly created property on success, NULL on failure.
+ */
+struct drm_property *drm_property_create_enum(struct drm_device *dev, int flags,
+					 const char *name,
+					 const struct drm_prop_enum_list *props,
+					 int num_values)
+{
+	struct drm_property *property;
+	int i, ret;
+
+	flags |= DRM_MODE_PROP_ENUM;
+
+	property = drm_property_create(dev, flags, name, num_values);
+	if (!property)
+		return NULL;
+
+	for (i = 0; i < num_values; i++) {
+		ret = drm_property_add_enum(property, i,
+				      props[i].type,
+				      props[i].name);
+		if (ret) {
+			drm_property_destroy(dev, property);
+			return NULL;
+		}
+	}
+
+	return property;
+}
+EXPORT_SYMBOL(drm_property_create_enum);
+
+/**
+ * drm_property_create_bitmask - create a new bitmask property type
+ * @dev: drm device
+ * @flags: flags specifying the property type
+ * @name: name of the property
+ * @props: enumeration lists with property bitflags
+ * @num_props: size of the @props array
+ * @supported_bits: bitmask of all supported enumeration values
+ *
+ * This creates a new bitmask drm property which can then be attached to a drm
+ * object with drm_object_attach_property. The returned property object must be
+ * freed with drm_property_destroy.
+ *
+ * Compared to plain enumeration properties userspace is allowed to set any
+ * or'ed together combination of the predefined property bitflag values
+ *
+ * Returns:
+ * A pointer to the newly created property on success, NULL on failure.
+ */
+struct drm_property *drm_property_create_bitmask(struct drm_device *dev,
+					 int flags, const char *name,
+					 const struct drm_prop_enum_list *props,
+					 int num_props,
+					 uint64_t supported_bits)
+{
+	struct drm_property *property;
+	int i, ret, index = 0;
+	int num_values = hweight64(supported_bits);
+
+	flags |= DRM_MODE_PROP_BITMASK;
+
+	property = drm_property_create(dev, flags, name, num_values);
+	if (!property)
+		return NULL;
+	for (i = 0; i < num_props; i++) {
+		if (!(supported_bits & (1ULL << props[i].type)))
+			continue;
+
+		if (WARN_ON(index >= num_values)) {
+			drm_property_destroy(dev, property);
+			return NULL;
+		}
+
+		ret = drm_property_add_enum(property, index++,
+				      props[i].type,
+				      props[i].name);
+		if (ret) {
+			drm_property_destroy(dev, property);
+			return NULL;
+		}
+	}
+
+	return property;
+}
+EXPORT_SYMBOL(drm_property_create_bitmask);
+
+static struct drm_property *property_create_range(struct drm_device *dev,
+					 int flags, const char *name,
+					 uint64_t min, uint64_t max)
+{
+	struct drm_property *property;
+
+	property = drm_property_create(dev, flags, name, 2);
+	if (!property)
+		return NULL;
+
+	property->values[0] = min;
+	property->values[1] = max;
+
+	return property;
+}
+
+/**
+ * drm_property_create_range - create a new unsigned ranged property type
+ * @dev: drm device
+ * @flags: flags specifying the property type
+ * @name: name of the property
+ * @min: minimum value of the property
+ * @max: maximum value of the property
+ *
+ * This creates a new generic drm property which can then be attached to a drm
+ * object with drm_object_attach_property. The returned property object must be
+ * freed with drm_property_destroy.
+ *
+ * Userspace is allowed to set any unsigned integer value in the (min, max)
+ * range inclusive.
+ *
+ * Returns:
+ * A pointer to the newly created property on success, NULL on failure.
+ */
+struct drm_property *drm_property_create_range(struct drm_device *dev, int flags,
+					 const char *name,
+					 uint64_t min, uint64_t max)
+{
+	return property_create_range(dev, DRM_MODE_PROP_RANGE | flags,
+			name, min, max);
+}
+EXPORT_SYMBOL(drm_property_create_range);
+
+/**
+ * drm_property_create_signed_range - create a new signed ranged property type
+ * @dev: drm device
+ * @flags: flags specifying the property type
+ * @name: name of the property
+ * @min: minimum value of the property
+ * @max: maximum value of the property
+ *
+ * This creates a new generic drm property which can then be attached to a drm
+ * object with drm_object_attach_property. The returned property object must be
+ * freed with drm_property_destroy.
+ *
+ * Userspace is allowed to set any signed integer value in the (min, max)
+ * range inclusive.
+ *
+ * Returns:
+ * A pointer to the newly created property on success, NULL on failure.
+ */
+struct drm_property *drm_property_create_signed_range(struct drm_device *dev,
+					 int flags, const char *name,
+					 int64_t min, int64_t max)
+{
+	return property_create_range(dev, DRM_MODE_PROP_SIGNED_RANGE | flags,
+			name, I642U64(min), I642U64(max));
+}
+EXPORT_SYMBOL(drm_property_create_signed_range);
+
+/**
+ * drm_property_create_object - create a new object property type
+ * @dev: drm device
+ * @flags: flags specifying the property type
+ * @name: name of the property
+ * @type: object type from DRM_MODE_OBJECT_* defines
+ *
+ * This creates a new generic drm property which can then be attached to a drm
+ * object with drm_object_attach_property. The returned property object must be
+ * freed with drm_property_destroy.
+ *
+ * Userspace is only allowed to set this to any property value of the given
+ * @type. Only useful for atomic properties, which is enforced.
+ *
+ * Returns:
+ * A pointer to the newly created property on success, NULL on failure.
+ */
+struct drm_property *drm_property_create_object(struct drm_device *dev,
+					 int flags, const char *name, uint32_t type)
+{
+	struct drm_property *property;
+
+	flags |= DRM_MODE_PROP_OBJECT;
+
+	if (WARN_ON(!(flags & DRM_MODE_PROP_ATOMIC)))
+		return NULL;
+
+	property = drm_property_create(dev, flags, name, 1);
+	if (!property)
+		return NULL;
+
+	property->values[0] = type;
+
+	return property;
+}
+EXPORT_SYMBOL(drm_property_create_object);
+
+/**
+ * drm_property_create_bool - create a new boolean property type
+ * @dev: drm device
+ * @flags: flags specifying the property type
+ * @name: name of the property
+ *
+ * This creates a new generic drm property which can then be attached to a drm
+ * object with drm_object_attach_property. The returned property object must be
+ * freed with drm_property_destroy.
+ *
+ * This is implemented as a ranged property with only {0, 1} as valid values.
+ *
+ * Returns:
+ * A pointer to the newly created property on success, NULL on failure.
+ */
+struct drm_property *drm_property_create_bool(struct drm_device *dev, int flags,
+					 const char *name)
+{
+	return drm_property_create_range(dev, flags, name, 0, 1);
+}
+EXPORT_SYMBOL(drm_property_create_bool);
+
+/**
+ * drm_property_add_enum - add a possible value to an enumeration property
+ * @property: enumeration property to change
+ * @index: index of the new enumeration
+ * @value: value of the new enumeration
+ * @name: symbolic name of the new enumeration
+ *
+ * This functions adds enumerations to a property.
+ *
+ * It's use is deprecated, drivers should use one of the more specific helpers
+ * to directly create the property with all enumerations already attached.
+ *
+ * Returns:
+ * Zero on success, error code on failure.
+ */
+int drm_property_add_enum(struct drm_property *property, int index,
+			  uint64_t value, const char *name)
+{
+	struct drm_property_enum *prop_enum;
+
+	if (!(drm_property_type_is(property, DRM_MODE_PROP_ENUM) ||
+			drm_property_type_is(property, DRM_MODE_PROP_BITMASK)))
+		return -EINVAL;
+
+	/*
+	 * Bitmask enum properties have the additional constraint of values
+	 * from 0 to 63
+	 */
+	if (drm_property_type_is(property, DRM_MODE_PROP_BITMASK) &&
+			(value > 63))
+		return -EINVAL;
+
+	if (!list_empty(&property->enum_list)) {
+		list_for_each_entry(prop_enum, &property->enum_list, head) {
+			if (prop_enum->value == value) {
+				strncpy(prop_enum->name, name, DRM_PROP_NAME_LEN);
+				prop_enum->name[DRM_PROP_NAME_LEN-1] = '\0';
+				return 0;
+			}
+		}
+	}
+
+	prop_enum = kzalloc(sizeof(struct drm_property_enum), GFP_KERNEL);
+	if (!prop_enum)
+		return -ENOMEM;
+
+	strncpy(prop_enum->name, name, DRM_PROP_NAME_LEN);
+	prop_enum->name[DRM_PROP_NAME_LEN-1] = '\0';
+	prop_enum->value = value;
+
+	property->values[index] = value;
+	list_add_tail(&prop_enum->head, &property->enum_list);
+	return 0;
+}
+EXPORT_SYMBOL(drm_property_add_enum);
+
+/**
+ * drm_property_destroy - destroy a drm property
+ * @dev: drm device
+ * @property: property to destry
+ *
+ * This function frees a property including any attached resources like
+ * enumeration values.
+ */
+void drm_property_destroy(struct drm_device *dev, struct drm_property *property)
+{
+	struct drm_property_enum *prop_enum, *pt;
+
+	list_for_each_entry_safe(prop_enum, pt, &property->enum_list, head) {
+		list_del(&prop_enum->head);
+		kfree(prop_enum);
+	}
+
+	if (property->num_values)
+		kfree(property->values);
+	drm_mode_object_unregister(dev, &property->base);
+	list_del(&property->head);
+	kfree(property);
+}
+EXPORT_SYMBOL(drm_property_destroy);
+
+/**
+ * drm_mode_getproperty_ioctl - get the property metadata
+ * @dev: DRM device
+ * @data: ioctl data
+ * @file_priv: DRM file info
+ *
+ * This function retrieves the metadata for a given property, like the different
+ * possible values for an enum property or the limits for a range property.
+ *
+ * Blob properties are special
+ *
+ * Called by the user via ioctl.
+ *
+ * Returns:
+ * Zero on success, negative errno on failure.
+ */
+int drm_mode_getproperty_ioctl(struct drm_device *dev,
+			       void *data, struct drm_file *file_priv)
+{
+	struct drm_mode_get_property *out_resp = data;
+	struct drm_property *property;
+	int enum_count = 0;
+	int value_count = 0;
+	int ret = 0, i;
+	int copied;
+	struct drm_property_enum *prop_enum;
+	struct drm_mode_property_enum __user *enum_ptr;
+	uint64_t __user *values_ptr;
+
+	if (!drm_core_check_feature(dev, DRIVER_MODESET))
+		return -EINVAL;
+
+	drm_modeset_lock_all(dev);
+	property = drm_property_find(dev, out_resp->prop_id);
+	if (!property) {
+		ret = -ENOENT;
+		goto done;
+	}
+
+	if (drm_property_type_is(property, DRM_MODE_PROP_ENUM) ||
+			drm_property_type_is(property, DRM_MODE_PROP_BITMASK)) {
+		list_for_each_entry(prop_enum, &property->enum_list, head)
+			enum_count++;
+	}
+
+	value_count = property->num_values;
+
+	strncpy(out_resp->name, property->name, DRM_PROP_NAME_LEN);
+	out_resp->name[DRM_PROP_NAME_LEN-1] = 0;
+	out_resp->flags = property->flags;
+
+	if ((out_resp->count_values >= value_count) && value_count) {
+		values_ptr = (uint64_t __user *)(unsigned long)out_resp->values_ptr;
+		for (i = 0; i < value_count; i++) {
+			if (copy_to_user(values_ptr + i, &property->values[i], sizeof(uint64_t))) {
+				ret = -EFAULT;
+				goto done;
+			}
+		}
+	}
+	out_resp->count_values = value_count;
+
+	if (drm_property_type_is(property, DRM_MODE_PROP_ENUM) ||
+			drm_property_type_is(property, DRM_MODE_PROP_BITMASK)) {
+		if ((out_resp->count_enum_blobs >= enum_count) && enum_count) {
+			copied = 0;
+			enum_ptr = (struct drm_mode_property_enum __user *)(unsigned long)out_resp->enum_blob_ptr;
+			list_for_each_entry(prop_enum, &property->enum_list, head) {
+
+				if (copy_to_user(&enum_ptr[copied].value, &prop_enum->value, sizeof(uint64_t))) {
+					ret = -EFAULT;
+					goto done;
+				}
+
+				if (copy_to_user(&enum_ptr[copied].name,
+						 &prop_enum->name, DRM_PROP_NAME_LEN)) {
+					ret = -EFAULT;
+					goto done;
+				}
+				copied++;
+			}
+		}
+		out_resp->count_enum_blobs = enum_count;
+	}
+
+	/*
+	 * NOTE: The idea seems to have been to use this to read all the blob
+	 * property values. But nothing ever added them to the corresponding
+	 * list, userspace always used the special-purpose get_blob ioctl to
+	 * read the value for a blob property. It also doesn't make a lot of
+	 * sense to return values here when everything else is just metadata for
+	 * the property itself.
+	 */
+	if (drm_property_type_is(property, DRM_MODE_PROP_BLOB))
+		out_resp->count_enum_blobs = 0;
+done:
+	drm_modeset_unlock_all(dev);
+	return ret;
+}
+
+static void drm_property_free_blob(struct kref *kref)
+{
+	struct drm_property_blob *blob =
+		container_of(kref, struct drm_property_blob, base.refcount);
+
+	mutex_lock(&blob->dev->mode_config.blob_lock);
+	list_del(&blob->head_global);
+	mutex_unlock(&blob->dev->mode_config.blob_lock);
+
+	drm_mode_object_unregister(blob->dev, &blob->base);
+
+	kfree(blob);
+}
+
+/**
+ * drm_property_create_blob - Create new blob property
+ *
+ * Creates a new blob property for a specified DRM device, optionally
+ * copying data.
+ *
+ * @dev: DRM device to create property for
+ * @length: Length to allocate for blob data
+ * @data: If specified, copies data into blob
+ *
+ * Returns:
+ * New blob property with a single reference on success, or an ERR_PTR
+ * value on failure.
+ */
+struct drm_property_blob *
+drm_property_create_blob(struct drm_device *dev, size_t length,
+			 const void *data)
+{
+	struct drm_property_blob *blob;
+	int ret;
+
+	if (!length || length > ULONG_MAX - sizeof(struct drm_property_blob))
+		return ERR_PTR(-EINVAL);
+
+	blob = kzalloc(sizeof(struct drm_property_blob)+length, GFP_KERNEL);
+	if (!blob)
+		return ERR_PTR(-ENOMEM);
+
+	/* This must be explicitly initialised, so we can safely call list_del
+	 * on it in the removal handler, even if it isn't in a file list. */
+	INIT_LIST_HEAD(&blob->head_file);
+	blob->length = length;
+	blob->dev = dev;
+
+	if (data)
+		memcpy(blob->data, data, length);
+
+	ret = drm_mode_object_get_reg(dev, &blob->base, DRM_MODE_OBJECT_BLOB,
+				      true, drm_property_free_blob);
+	if (ret) {
+		kfree(blob);
+		return ERR_PTR(-EINVAL);
+	}
+
+	mutex_lock(&dev->mode_config.blob_lock);
+	list_add_tail(&blob->head_global,
+	              &dev->mode_config.property_blob_list);
+	mutex_unlock(&dev->mode_config.blob_lock);
+
+	return blob;
+}
+EXPORT_SYMBOL(drm_property_create_blob);
+
+/**
+ * drm_property_unreference_blob - Unreference a blob property
+ *
+ * Drop a reference on a blob property. May free the object.
+ *
+ * @blob: Pointer to blob property
+ */
+void drm_property_unreference_blob(struct drm_property_blob *blob)
+{
+	if (!blob)
+		return;
+
+	drm_mode_object_unreference(&blob->base);
+}
+EXPORT_SYMBOL(drm_property_unreference_blob);
+
+/**
+ * drm_property_destroy_user_blobs - destroy all blobs created by this client
+ * @dev:       DRM device
+ * @file_priv: destroy all blobs owned by this file handle
+ */
+void drm_property_destroy_user_blobs(struct drm_device *dev,
+				     struct drm_file *file_priv)
+{
+	struct drm_property_blob *blob, *bt;
+
+	/*
+	 * When the file gets released that means no one else can access the
+	 * blob list any more, so no need to grab dev->blob_lock.
+	 */
+	list_for_each_entry_safe(blob, bt, &file_priv->blobs, head_file) {
+		list_del_init(&blob->head_file);
+		drm_property_unreference_blob(blob);
+	}
+}
+
+/**
+ * drm_property_reference_blob - Take a reference on an existing property
+ *
+ * Take a new reference on an existing blob property.
+ *
+ * @blob: Pointer to blob property
+ */
+struct drm_property_blob *drm_property_reference_blob(struct drm_property_blob *blob)
+{
+	drm_mode_object_reference(&blob->base);
+	return blob;
+}
+EXPORT_SYMBOL(drm_property_reference_blob);
+
+/**
+ * drm_property_lookup_blob - look up a blob property and take a reference
+ * @dev: drm device
+ * @id: id of the blob property
+ *
+ * If successful, this takes an additional reference to the blob property.
+ * callers need to make sure to eventually unreference the returned property
+ * again, using @drm_property_unreference_blob.
+ */
+struct drm_property_blob *drm_property_lookup_blob(struct drm_device *dev,
+					           uint32_t id)
+{
+	struct drm_mode_object *obj;
+	struct drm_property_blob *blob = NULL;
+
+	obj = __drm_mode_object_find(dev, id, DRM_MODE_OBJECT_BLOB);
+	if (obj)
+		blob = obj_to_blob(obj);
+	return blob;
+}
+EXPORT_SYMBOL(drm_property_lookup_blob);
+
+/**
+ * drm_property_replace_global_blob - atomically replace existing blob property
+ * @dev: drm device
+ * @replace: location of blob property pointer to be replaced
+ * @length: length of data for new blob, or 0 for no data
+ * @data: content for new blob, or NULL for no data
+ * @obj_holds_id: optional object for property holding blob ID
+ * @prop_holds_id: optional property holding blob ID
+ * @return 0 on success or error on failure
+ *
+ * This function will atomically replace a global property in the blob list,
+ * optionally updating a property which holds the ID of that property. It is
+ * guaranteed to be atomic: no caller will be allowed to see intermediate
+ * results, and either the entire operation will succeed and clean up the
+ * previous property, or it will fail and the state will be unchanged.
+ *
+ * If length is 0 or data is NULL, no new blob will be created, and the holding
+ * property, if specified, will be set to 0.
+ *
+ * Access to the replace pointer is assumed to be protected by the caller, e.g.
+ * by holding the relevant modesetting object lock for its parent.
+ *
+ * For example, a drm_connector has a 'PATH' property, which contains the ID
+ * of a blob property with the value of the MST path information. Calling this
+ * function with replace pointing to the connector's path_blob_ptr, length and
+ * data set for the new path information, obj_holds_id set to the connector's
+ * base object, and prop_holds_id set to the path property name, will perform
+ * a completely atomic update. The access to path_blob_ptr is protected by the
+ * caller holding a lock on the connector.
+ */
+int drm_property_replace_global_blob(struct drm_device *dev,
+				     struct drm_property_blob **replace,
+				     size_t length,
+				     const void *data,
+				     struct drm_mode_object *obj_holds_id,
+				     struct drm_property *prop_holds_id)
+{
+	struct drm_property_blob *new_blob = NULL;
+	struct drm_property_blob *old_blob = NULL;
+	int ret;
+
+	WARN_ON(replace == NULL);
+
+	old_blob = *replace;
+
+	if (length && data) {
+		new_blob = drm_property_create_blob(dev, length, data);
+		if (IS_ERR(new_blob))
+			return PTR_ERR(new_blob);
+	}
+
+	/* This does not need to be synchronised with blob_lock, as the
+	 * get_properties ioctl locks all modesetting objects, and
+	 * obj_holds_id must be locked before calling here, so we cannot
+	 * have its value out of sync with the list membership modified
+	 * below under blob_lock. */
+	if (obj_holds_id) {
+		ret = drm_object_property_set_value(obj_holds_id,
+						    prop_holds_id,
+						    new_blob ?
+						        new_blob->base.id : 0);
+		if (ret != 0)
+			goto err_created;
+	}
+
+	drm_property_unreference_blob(old_blob);
+	*replace = new_blob;
+
+	return 0;
+
+err_created:
+	drm_property_unreference_blob(new_blob);
+	return ret;
+}
+EXPORT_SYMBOL(drm_property_replace_global_blob);
+
+/**
+ * drm_mode_getblob_ioctl - get the contents of a blob property value
+ * @dev: DRM device
+ * @data: ioctl data
+ * @file_priv: DRM file info
+ *
+ * This function retrieves the contents of a blob property. The value stored in
+ * an object's blob property is just a normal modeset object id.
+ *
+ * Called by the user via ioctl.
+ *
+ * Returns:
+ * Zero on success, negative errno on failure.
+ */
+int drm_mode_getblob_ioctl(struct drm_device *dev,
+			   void *data, struct drm_file *file_priv)
+{
+	struct drm_mode_get_blob *out_resp = data;
+	struct drm_property_blob *blob;
+	int ret = 0;
+	void __user *blob_ptr;
+
+	if (!drm_core_check_feature(dev, DRIVER_MODESET))
+		return -EINVAL;
+
+	blob = drm_property_lookup_blob(dev, out_resp->blob_id);
+	if (!blob)
+		return -ENOENT;
+
+	if (out_resp->length == blob->length) {
+		blob_ptr = (void __user *)(unsigned long)out_resp->data;
+		if (copy_to_user(blob_ptr, blob->data, blob->length)) {
+			ret = -EFAULT;
+			goto unref;
+		}
+	}
+	out_resp->length = blob->length;
+unref:
+	drm_property_unreference_blob(blob);
+
+	return ret;
+}
+
+/**
+ * drm_mode_createblob_ioctl - create a new blob property
+ * @dev: DRM device
+ * @data: ioctl data
+ * @file_priv: DRM file info
+ *
+ * This function creates a new blob property with user-defined values. In order
+ * to give us sensible validation and checking when creating, rather than at
+ * every potential use, we also require a type to be provided upfront.
+ *
+ * Called by the user via ioctl.
+ *
+ * Returns:
+ * Zero on success, negative errno on failure.
+ */
+int drm_mode_createblob_ioctl(struct drm_device *dev,
+			      void *data, struct drm_file *file_priv)
+{
+	struct drm_mode_create_blob *out_resp = data;
+	struct drm_property_blob *blob;
+	void __user *blob_ptr;
+	int ret = 0;
+
+	if (!drm_core_check_feature(dev, DRIVER_MODESET))
+		return -EINVAL;
+
+	blob = drm_property_create_blob(dev, out_resp->length, NULL);
+	if (IS_ERR(blob))
+		return PTR_ERR(blob);
+
+	blob_ptr = (void __user *)(unsigned long)out_resp->data;
+	if (copy_from_user(blob->data, blob_ptr, out_resp->length)) {
+		ret = -EFAULT;
+		goto out_blob;
+	}
+
+	/* Dropping the lock between create_blob and our access here is safe
+	 * as only the same file_priv can remove the blob; at this point, it is
+	 * not associated with any file_priv. */
+	mutex_lock(&dev->mode_config.blob_lock);
+	out_resp->blob_id = blob->base.id;
+	list_add_tail(&blob->head_file, &file_priv->blobs);
+	mutex_unlock(&dev->mode_config.blob_lock);
+
+	return 0;
+
+out_blob:
+	drm_property_unreference_blob(blob);
+	return ret;
+}
+
+/**
+ * drm_mode_destroyblob_ioctl - destroy a user blob property
+ * @dev: DRM device
+ * @data: ioctl data
+ * @file_priv: DRM file info
+ *
+ * Destroy an existing user-defined blob property.
+ *
+ * Called by the user via ioctl.
+ *
+ * Returns:
+ * Zero on success, negative errno on failure.
+ */
+int drm_mode_destroyblob_ioctl(struct drm_device *dev,
+			       void *data, struct drm_file *file_priv)
+{
+	struct drm_mode_destroy_blob *out_resp = data;
+	struct drm_property_blob *blob = NULL, *bt;
+	bool found = false;
+	int ret = 0;
+
+	if (!drm_core_check_feature(dev, DRIVER_MODESET))
+		return -EINVAL;
+
+	blob = drm_property_lookup_blob(dev, out_resp->blob_id);
+	if (!blob)
+		return -ENOENT;
+
+	mutex_lock(&dev->mode_config.blob_lock);
+	/* Ensure the property was actually created by this user. */
+	list_for_each_entry(bt, &file_priv->blobs, head_file) {
+		if (bt == blob) {
+			found = true;
+			break;
+		}
+	}
+
+	if (!found) {
+		ret = -EPERM;
+		goto err;
+	}
+
+	/* We must drop head_file here, because we may not be the last
+	 * reference on the blob. */
+	list_del_init(&blob->head_file);
+	mutex_unlock(&dev->mode_config.blob_lock);
+
+	/* One reference from lookup, and one from the filp. */
+	drm_property_unreference_blob(blob);
+	drm_property_unreference_blob(blob);
+
+	return 0;
+
+err:
+	mutex_unlock(&dev->mode_config.blob_lock);
+	drm_property_unreference_blob(blob);
+
+	return ret;
+}
+
+/* Some properties could refer to dynamic refcnt'd objects, or things that
+ * need special locking to handle lifetime issues (ie. to ensure the prop
+ * value doesn't become invalid part way through the property update due to
+ * race).  The value returned by reference via 'obj' should be passed back
+ * to drm_property_change_valid_put() after the property is set (and the
+ * object to which the property is attached has a chance to take it's own
+ * reference).
+ */
+bool drm_property_change_valid_get(struct drm_property *property,
+					 uint64_t value, struct drm_mode_object **ref)
+{
+	int i;
+
+	if (property->flags & DRM_MODE_PROP_IMMUTABLE)
+		return false;
+
+	*ref = NULL;
+
+	if (drm_property_type_is(property, DRM_MODE_PROP_RANGE)) {
+		if (value < property->values[0] || value > property->values[1])
+			return false;
+		return true;
+	} else if (drm_property_type_is(property, DRM_MODE_PROP_SIGNED_RANGE)) {
+		int64_t svalue = U642I64(value);
+
+		if (svalue < U642I64(property->values[0]) ||
+				svalue > U642I64(property->values[1]))
+			return false;
+		return true;
+	} else if (drm_property_type_is(property, DRM_MODE_PROP_BITMASK)) {
+		uint64_t valid_mask = 0;
+
+		for (i = 0; i < property->num_values; i++)
+			valid_mask |= (1ULL << property->values[i]);
+		return !(value & ~valid_mask);
+	} else if (drm_property_type_is(property, DRM_MODE_PROP_BLOB)) {
+		struct drm_property_blob *blob;
+
+		if (value == 0)
+			return true;
+
+		blob = drm_property_lookup_blob(property->dev, value);
+		if (blob) {
+			*ref = &blob->base;
+			return true;
+		} else {
+			return false;
+		}
+	} else if (drm_property_type_is(property, DRM_MODE_PROP_OBJECT)) {
+		/* a zero value for an object property translates to null: */
+		if (value == 0)
+			return true;
+
+		*ref = __drm_mode_object_find(property->dev, value,
+					      property->values[0]);
+		return *ref != NULL;
+	}
+
+	for (i = 0; i < property->num_values; i++)
+		if (property->values[i] == value)
+			return true;
+	return false;
+}
+
+void drm_property_change_valid_put(struct drm_property *property,
+		struct drm_mode_object *ref)
+{
+	if (!ref)
+		return;
+
+	if (drm_property_type_is(property, DRM_MODE_PROP_OBJECT)) {
+		drm_mode_object_unreference(ref);
+	} else if (drm_property_type_is(property, DRM_MODE_PROP_BLOB))
+		drm_property_unreference_blob(obj_to_blob(ref));
+}