OSCL-LXR linux-6.0.1/​drivers/​gpu/​drm/​drm_property.c	Source navigation Diff markup Identifier search General search
	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 /*
  * 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 <linux/uaccess.h>
 
 #include <drm/drm_crtc.h>
 #include <drm/drm_drv.h>
 #include <drm/drm_file.h>
 #include <drm/drm_framebuffer.h>
 #include <drm/drm_property.h>
 
 #include "drm_crtc_internal.h"
 
 /**
  * DOC: overview
  *
  * Properties as represented by &drm_property are used to extend the modeset
  * interface exposed to userspace. For the atomic modeset IOCTL properties are
  * even the only way to transport metadata about the desired new modeset
  * configuration from userspace to the kernel. Properties have a well-defined
  * value range, which is enforced by the drm core. See the documentation of the
  * flags member of &struct drm_property for an overview of the different
  * property types and ranges.
  *
  * Properties don't store the current value directly, but need to be
  * instantiated by attaching them to a &drm_mode_object with
  * drm_object_attach_property().
  *
  * Property values are only 64bit. To support bigger piles of data (like gamma
  * tables, color correction matrices or large structures) a property can instead
  * point at a &drm_property_blob with that additional data.
  *
  * Properties are defined by their symbolic name, userspace must keep a
  * per-object mapping from those names to the property ID used in the atomic
  * IOCTL and in the get/set property IOCTL.
  */
 
 static bool drm_property_flags_valid(u32 flags)
 {
     u32 legacy_type = flags & DRM_MODE_PROP_LEGACY_TYPE;
     u32 ext_type = flags & DRM_MODE_PROP_EXTENDED_TYPE;
 
     /* Reject undefined/deprecated flags */
     if (flags & ~(DRM_MODE_PROP_LEGACY_TYPE |
               DRM_MODE_PROP_EXTENDED_TYPE |
               DRM_MODE_PROP_IMMUTABLE |
               DRM_MODE_PROP_ATOMIC))
         return false;
 
     /* We want either a legacy type or an extended type, but not both */
     if (!legacy_type == !ext_type)
         return false;
 
     /* Only one legacy type at a time please */
     if (legacy_type && !is_power_of_2(legacy_type))
         return false;
 
     return true;
 }
 
 /**
  * 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(), which is done automatically when
  * calling drm_mode_config_cleanup().
  *
  * Returns:
  * A pointer to the newly created property on success, NULL on failure.
  */
 struct drm_property *drm_property_create(struct drm_device *dev,
                      u32 flags, const char *name,
                      int num_values)
 {
     struct drm_property *property = NULL;
     int ret;
 
     if (WARN_ON(!drm_property_flags_valid(flags)))
         return NULL;
 
     if (WARN_ON(strlen(name) >= DRM_PROP_NAME_LEN))
         return NULL;
 
     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_add(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);
 
     strscpy_pad(property->name, name, DRM_PROP_NAME_LEN);
 
     list_add_tail(&property->head, &dev->mode_config.property_list);
 
     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(), which is done automatically when
  * calling drm_mode_config_cleanup().
  *
  * 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,
                           u32 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,
                         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(), which is done automatically when
  * calling drm_mode_config_cleanup().
  *
  * 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,
                          u32 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;
     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;
 
         ret = drm_property_add_enum(property,
                         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,
                           u32 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(), which is done automatically when
  * calling drm_mode_config_cleanup().
  *
  * 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,
                            u32 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(), which is done automatically when
  * calling drm_mode_config_cleanup().
  *
  * 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,
                               u32 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(), which is done automatically when
  * calling drm_mode_config_cleanup().
  *
  * 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,
                         u32 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(), which is done automatically when
  * calling drm_mode_config_cleanup().
  *
  * 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,
                           u32 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
  * @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,
               uint64_t value, const char *name)
 {
     struct drm_property_enum *prop_enum;
     int index = 0;
 
     if (WARN_ON(strlen(name) >= DRM_PROP_NAME_LEN))
         return -EINVAL;
 
     if (WARN_ON(!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 (WARN_ON(drm_property_type_is(property, DRM_MODE_PROP_BITMASK) &&
             value > 63))
         return -EINVAL;
 
     list_for_each_entry(prop_enum, &property->enum_list, head) {
         if (WARN_ON(prop_enum->value == value))
             return -EINVAL;
         index++;
     }
 
     if (WARN_ON(index >= property->num_values))
         return -EINVAL;
 
     prop_enum = kzalloc(sizeof(struct drm_property_enum), GFP_KERNEL);
     if (!prop_enum)
         return -ENOMEM;
 
     strscpy_pad(prop_enum->name, name, DRM_PROP_NAME_LEN);
     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 destroy
  *
  * 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);
 
 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 i, 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 -EOPNOTSUPP;
 
     property = drm_property_find(dev, file_priv, out_resp->prop_id);
     if (!property)
         return -ENOENT;
 
     strscpy_pad(out_resp->name, property->name, DRM_PROP_NAME_LEN);
     out_resp->flags = property->flags;
 
     value_count = property->num_values;
     values_ptr = u64_to_user_ptr(out_resp->values_ptr);
 
     for (i = 0; i < value_count; i++) {
         if (i < out_resp->count_values &&
             put_user(property->values[i], values_ptr + i)) {
             return -EFAULT;
         }
     }
     out_resp->count_values = value_count;
 
     copied = 0;
     enum_ptr = u64_to_user_ptr(out_resp->enum_blob_ptr);
 
     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++;
             if (out_resp->count_enum_blobs < enum_count)
                 continue;
 
             if (copy_to_user(&enum_ptr[copied].value,
                      &prop_enum->value, sizeof(uint64_t)))
                 return -EFAULT;
 
             if (copy_to_user(&enum_ptr[copied].name,
                      &prop_enum->name, DRM_PROP_NAME_LEN))
                 return -EFAULT;
             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;
 
     return 0;
 }
 
 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);
 
     kvfree(blob);
 }
 
 /**
  * drm_property_create_blob - Create new blob property
  * @dev: DRM device to create property for
  * @length: Length to allocate for blob data
  * @data: If specified, copies data into blob
  *
  * Creates a new blob property for a specified DRM device, optionally
  * copying data. Note that blob properties are meant to be invariant, hence the
  * data must be filled out before the blob is used as the value of any property.
  *
  * 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 > INT_MAX - sizeof(struct drm_property_blob))
         return ERR_PTR(-EINVAL);
 
     blob = kvzalloc(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->data = (void *)blob + sizeof(*blob);
     blob->length = length;
     blob->dev = dev;
 
     if (data)
         memcpy(blob->data, data, length);
 
     ret = __drm_mode_object_add(dev, &blob->base, DRM_MODE_OBJECT_BLOB,
                     true, drm_property_free_blob);
     if (ret) {
         kvfree(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_blob_put - release a blob property reference
  * @blob: DRM blob property
  *
  * Releases a reference to a blob property. May free the object.
  */
 void drm_property_blob_put(struct drm_property_blob *blob)
 {
     if (!blob)
         return;
 
     drm_mode_object_put(&blob->base);
 }
 EXPORT_SYMBOL(drm_property_blob_put);
 
 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_blob_put(blob);
     }
 }
 
 /**
  * drm_property_blob_get - acquire blob property reference
  * @blob: DRM blob property
  *
  * Acquires a reference to an existing blob property. Returns @blob, which
  * allows this to be used as a shorthand in assignments.
  */
 struct drm_property_blob *drm_property_blob_get(struct drm_property_blob *blob)
 {
     drm_mode_object_get(&blob->base);
     return blob;
 }
 EXPORT_SYMBOL(drm_property_blob_get);
 
 /**
  * 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 unreferenced the returned property
  * again, using drm_property_blob_put().
  *
  * Return:
  * NULL on failure, pointer to the blob on success.
  */
 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, NULL, 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 - 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 replace a global property in the blob list, optionally
  * updating a property which holds the ID of that property.
  *
  * 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);
     }
 
     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_blob_put(old_blob);
     *replace = new_blob;
 
     return 0;
 
 err_created:
     drm_property_blob_put(new_blob);
     return ret;
 }
 EXPORT_SYMBOL(drm_property_replace_global_blob);
 
 /**
  * drm_property_replace_blob - replace a blob property
  * @blob: a pointer to the member blob to be replaced
  * @new_blob: the new blob to replace with
  *
  * Return: true if the blob was in fact replaced.
  */
 bool drm_property_replace_blob(struct drm_property_blob **blob,
                    struct drm_property_blob *new_blob)
 {
     struct drm_property_blob *old_blob = *blob;
 
     if (old_blob == new_blob)
         return false;
 
     drm_property_blob_put(old_blob);
     if (new_blob)
         drm_property_blob_get(new_blob);
     *blob = new_blob;
     return true;
 }
 EXPORT_SYMBOL(drm_property_replace_blob);
 
 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;
 
     if (!drm_core_check_feature(dev, DRIVER_MODESET))
         return -EOPNOTSUPP;
 
     blob = drm_property_lookup_blob(dev, out_resp->blob_id);
     if (!blob)
         return -ENOENT;
 
     if (out_resp->length == blob->length) {
         if (copy_to_user(u64_to_user_ptr(out_resp->data),
                  blob->data,
                  blob->length)) {
             ret = -EFAULT;
             goto unref;
         }
     }
     out_resp->length = blob->length;
 unref:
     drm_property_blob_put(blob);
 
     return ret;
 }
 
 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;
     int ret = 0;
 
     if (!drm_core_check_feature(dev, DRIVER_MODESET))
         return -EOPNOTSUPP;
 
     blob = drm_property_create_blob(dev, out_resp->length, NULL);
     if (IS_ERR(blob))
         return PTR_ERR(blob);
 
     if (copy_from_user(blob->data,
                u64_to_user_ptr(out_resp->data),
                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_blob_put(blob);
     return ret;
 }
 
 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 -EOPNOTSUPP;
 
     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_blob_put(blob);
     drm_property_blob_put(blob);
 
     return 0;
 
 err:
     mutex_unlock(&dev->mode_config.blob_lock);
     drm_property_blob_put(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 its 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, NULL, 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_put(ref);
     } else if (drm_property_type_is(property, DRM_MODE_PROP_BLOB))
         drm_property_blob_put(obj_to_blob(ref));
 }

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