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drm: document drm_auth.c

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Also extract drm_auth.h for nicer grouping.

v2: Nuke the other comments since they don't really explain a lot, and
within the drm core we generally only document functions exported to
drivers: The main audience for these docs are driver writers.

v3: Limit the exposure of drm_master internals by only including
drm_auth.h where it is neede (Chris).

v4: Spelling polish (Emil).

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
This commit is contained in:
Daniel Vetter 2016-06-21 10:54:22 +02:00
parent 0aae5920a8
commit 3b96a0b140
9 changed files with 119 additions and 57 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
Documentation/gpu/drm-uapi.rst
View File

@ -20,6 +20,19 @@ libdrm Device Lookup
.. kernel-doc:: drivers/gpu/drm/drm_ioctl.c
:doc: getunique and setversion story
Primary Nodes, DRM Master and Authentication
============================================
.. kernel-doc:: drivers/gpu/drm/drm_auth.c
:doc: master and authentication
.. kernel-doc:: drivers/gpu/drm/drm_auth.c
:export:
.. kernel-doc:: include/drm/drm_auth.h
:internal:
Render nodes
============

68
drivers/gpu/drm/drm_auth.c
View File

@ -33,17 +33,27 @@
#include "drm_legacy.h"
/**
* drm_getmagic - Get unique magic of a client
* @dev: DRM device to operate on
* @data: ioctl data containing the drm_auth object
* @file_priv: DRM file that performs the operation
* DOC: master and authentication
*
* This looks up the unique magic of the passed client and returns it. If the
* client did not have a magic assigned, yet, a new one is registered. The magic
* is stored in the passed drm_auth object.
* struct &drm_master is used to track groups of clients with open
* primary/legacy device nodes. For every struct &drm_file which has had at
* least once successfully became the device master (either through the
* SET_MASTER IOCTL, or implicitly through opening the primary device node when
* no one else is the current master that time) there exists one &drm_master.
* This is noted in the is_master member of &drm_file. All other clients have
* just a pointer to the &drm_master they are associated with.
*
* Returns: 0 on success, negative error code on failure.
* In addition only one &drm_master can be the current master for a &drm_device.
* It can be switched through the DROP_MASTER and SET_MASTER IOCTL, or
* implicitly through closing/openeing the primary device node. See also
* drm_is_current_master().
*
* Clients can authenticate against the current master (if it matches their own)
* using the GETMAGIC and AUTHMAGIC IOCTLs. Together with exchanging masters,
* this allows controlled access to the device for an entire group of mutually
* trusted clients.
*/
int drm_getmagic(struct drm_device *dev, void *data, struct drm_file *file_priv)
{
struct drm_auth *auth = data;
@ -64,16 +74,6 @@ int drm_getmagic(struct drm_device *dev, void *data, struct drm_file *file_priv)
return ret < 0 ? ret : 0;
}
/**
* drm_authmagic - Authenticate client with a magic
* @dev: DRM device to operate on
* @data: ioctl data containing the drm_auth object
* @file_priv: DRM file that performs the operation
*
* This looks up a DRM client by the passed magic and authenticates it.
*
* Returns: 0 on success, negative error code on failure.
*/
int drm_authmagic(struct drm_device *dev, void *data,
struct drm_file *file_priv)
{
@ -126,16 +126,6 @@ static int drm_set_master(struct drm_device *dev, struct drm_file *fpriv,
return ret;
}
/*
* drm_new_set_master - Allocate a new master object and become master for the
* associated master realm.
*
* @dev: The associated device.
* @fpriv: File private identifying the client.
*
* This function must be called with dev::master_mutex held.
* Returns negative error code on failure. Zero on success.
*/
static int drm_new_set_master(struct drm_device *dev, struct drm_file *fpriv)
{
struct drm_master *old_master;
@ -286,12 +276,28 @@ out:
mutex_unlock(&dev->master_mutex);
}
/**
* drm_is_current_master - checks whether @priv is the current master
* @fpriv: DRM file private
*
* Checks whether @fpriv is current master on its device. This decides whether a
* client is allowed to run DRM_MASTER IOCTLs.
*
* Most of the modern IOCTL which require DRM_MASTER are for kernel modesetting
* - the current master is assumed to own the non-shareable display hardware.
*/
bool drm_is_current_master(struct drm_file *fpriv)
{
return fpriv->is_master && fpriv->master == fpriv->minor->dev->master;
}
EXPORT_SYMBOL(drm_is_current_master);
/**
* drm_master_get - reference a master pointer
* @master: struct &drm_master
*
* Increments the reference count of @master and returns a pointer to @master.
*/
struct drm_master *drm_master_get(struct drm_master *master)
{
kref_get(&master->refcount);
@ -314,6 +320,12 @@ static void drm_master_destroy(struct kref *kref)
kfree(master);
}
/**
* drm_master_put - unreference and clear a master pointer
* @master: pointer to a pointer of struct &drm_master
*
* This decrements the &drm_master behind @master and sets it to NULL.
*/
void drm_master_put(struct drm_master **master)
{
kref_put(&(*master)->refcount, drm_master_destroy);

1
drivers/gpu/drm/drm_crtc.c
View File

@ -39,6 +39,7 @@
#include <drm/drm_fourcc.h>
#include <drm/drm_modeset_lock.h>
#include <drm/drm_atomic.h>
#include <drm/drm_auth.h>
#include "drm_crtc_internal.h"
#include "drm_internal.h"

1
drivers/gpu/drm/drm_ioctl.c
View File

@ -30,6 +30,7 @@
#include <drm/drmP.h>
#include <drm/drm_core.h>
#include <drm/drm_auth.h>
#include "drm_legacy.h"
#include "drm_internal.h"
#include "drm_crtc_internal.h"

1
drivers/gpu/drm/i915/i915_drv.h
View File

@ -47,6 +47,7 @@
#include <drm/intel-gtt.h>
#include <drm/drm_legacy.h> /* for struct drm_dma_handle */
#include <drm/drm_gem.h>
#include <drm/drm_auth.h>
#include "i915_params.h"
#include "i915_reg.h"

1
drivers/gpu/drm/vmwgfx/vmwgfx_drv.h
View File

@ -32,6 +32,7 @@
#include <drm/drmP.h>
#include <drm/vmwgfx_drm.h>
#include <drm/drm_hashtab.h>
#include <drm/drm_auth.h>
#include <linux/suspend.h>
#include <drm/ttm/ttm_bo_driver.h>
#include <drm/ttm/ttm_object.h>

30
include/drm/drmP.h
View File

@ -86,6 +86,7 @@ struct drm_local_map;
struct drm_device_dma;
struct drm_dma_handle;
struct drm_gem_object;
struct drm_master;
struct device_node;
struct videomode;
@ -373,30 +374,6 @@ struct drm_lock_data {
int idle_has_lock;
};
/**
* struct drm_master - drm master structure
*
* @refcount: Refcount for this master object.
* @dev: Link back to the DRM device
* @unique: Unique identifier: e.g. busid. Protected by drm_global_mutex.
* @unique_len: Length of unique field. Protected by drm_global_mutex.
* @magic_map: Map of used authentication tokens. Protected by struct_mutex.
* @lock: DRI lock information.
* @driver_priv: Pointer to driver-private information.
*
* Note that master structures are only relevant for the legacy/primary device
* nodes, hence there can only be one per device, not one per drm_minor.
*/
struct drm_master {
struct kref refcount;
struct drm_device *dev;
char *unique;
int unique_len;
struct idr magic_map;
struct drm_lock_data lock;
void *driver_priv;
};
/* Flags and return codes for get_vblank_timestamp() driver function. */
#define DRM_CALLED_FROM_VBLIRQ 1
#define DRM_VBLANKTIME_SCANOUTPOS_METHOD (1 << 0)
@ -1012,11 +989,6 @@ static inline wait_queue_head_t *drm_crtc_vblank_waitqueue(struct drm_crtc *crtc
extern void drm_vblank_pre_modeset(struct drm_device *dev, unsigned int pipe);
extern void drm_vblank_post_modeset(struct drm_device *dev, unsigned int pipe);
/* drm_auth.c */
struct drm_master *drm_master_get(struct drm_master *master);
void drm_master_put(struct drm_master **master);
bool drm_is_current_master(struct drm_file *fpriv);
/* drm_drv.c */
void drm_put_dev(struct drm_device *dev);
void drm_unplug_dev(struct drm_device *dev);

59
include/drm/drm_auth.h Normal file
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@ -0,0 +1,59 @@
/*
* Internal Header for the Direct Rendering Manager
*
* Copyright 2016 Intel Corporation
*
* Author: Daniel Vetter <daniel.vetter@ffwll.ch>
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*/
#ifndef _DRM_AUTH_H_
#define _DRM_AUTH_H_
/**
* struct drm_master - drm master structure
*
* @refcount: Refcount for this master object.
* @dev: Link back to the DRM device
* @unique: Unique identifier: e.g. busid. Protected by drm_global_mutex.
* @unique_len: Length of unique field. Protected by drm_global_mutex.
* @magic_map: Map of used authentication tokens. Protected by struct_mutex.
* @lock: DRI lock information.
* @driver_priv: Pointer to driver-private information.
*
* Note that master structures are only relevant for the legacy/primary device
* nodes, hence there can only be one per device, not one per drm_minor.
*/
struct drm_master {
struct kref refcount;
struct drm_device *dev;
char *unique;
int unique_len;
struct idr magic_map;
struct drm_lock_data lock;
void *driver_priv;
};
struct drm_master *drm_master_get(struct drm_master *master);
void drm_master_put(struct drm_master **master);
bool drm_is_current_master(struct drm_file *fpriv);
#endif

2
include/drm/drm_legacy.h
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@ -1,6 +1,8 @@
#ifndef __DRM_DRM_LEGACY_H__
#define __DRM_DRM_LEGACY_H__
#include <drm/drm_auth.h>
/*
* Legacy driver interfaces for the Direct Rendering Manager
*