[PATCH 16/16] drm: document drm_auth.c
Daniel Vetter
daniel.vetter at ffwll.ch
Fri Jun 17 07:33:34 UTC 2016
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).
Cc: Chris Wilson <chris at chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
---
Documentation/DocBook/gpu.tmpl | 6 ++++
drivers/gpu/drm/drm_auth.c | 69 +++++++++++++++++++++----------------
drivers/gpu/drm/drm_crtc.c | 1 +
drivers/gpu/drm/drm_ioctl.c | 1 +
drivers/gpu/drm/i915/i915_drv.h | 1 +
drivers/gpu/drm/vmwgfx/vmwgfx_drv.h | 1 +
include/drm/drmP.h | 30 +---------------
include/drm/drm_auth.h | 59 +++++++++++++++++++++++++++++++
include/drm/drm_legacy.h | 2 ++
9 files changed, 112 insertions(+), 58 deletions(-)
create mode 100644 include/drm/drm_auth.h
diff --git a/Documentation/DocBook/gpu.tmpl b/Documentation/DocBook/gpu.tmpl
index 94c6bdee8080..b7f6316b7bee 100644
--- a/Documentation/DocBook/gpu.tmpl
+++ b/Documentation/DocBook/gpu.tmpl
@@ -3103,6 +3103,12 @@ int num_ioctls;</synopsis>
!Pdrivers/gpu/drm/drm_vma_manager.c getunique and setversion story
</sect1>
<sect1>
+ <title>Primary Nodes, DRM Master and Authentication</title>
+!Pdrivers/gpu/drm_auth.c master and authentication
+!Edrivers/gpu/drm_auth.c
+!Einclude/drm/drm_auth.h
+ </sect1>
+ <sect1>
<title>Render nodes</title>
<para>
DRM core provides multiple character-devices for user-space to use.
diff --git a/drivers/gpu/drm/drm_auth.c b/drivers/gpu/drm/drm_auth.c
index b4dfa8ab20d7..3774b9964dbe 100644
--- a/drivers/gpu/drm/drm_auth.c
+++ b/drivers/gpu/drm/drm_auth.c
@@ -32,18 +32,27 @@
#include "drm_internal.h"
#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
+ *
+ * struct &drm_master is used to track groups of clients with open
+ * primary/legacy device nodes. For every struct &drm_file which 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_master. All other clients have just a pointer to the
+ * &drm_master they are associated with.
*
- * 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.
+ * 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().
*
- * Returns: 0 on success, negative error code on failure.
+ * 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 +73,6 @@ 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 +125,6 @@ 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;
@@ -288,12 +277,28 @@ out:
mutex_unlock(&dev->master_mutex);
}
+/**
+ * drm_is_current_master - checks whether this master is the current one
+ * @fpriv: DRM file private
+ *
+ * Checks whether @fpriv is a master and that it is the 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.
+ */
struct drm_master *drm_master_get(struct drm_master *master)
{
kref_get(&master->refcount);
@@ -316,6 +321,12 @@ 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);
diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index 81083f98d155..871af372662d 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -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"
diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
index a0c1d172954d..88796a383e40 100644
--- a/drivers/gpu/drm/drm_ioctl.c
+++ b/drivers/gpu/drm/drm_ioctl.c
@@ -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"
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 9fa9698fe247..0f8632c93e95 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -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"
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h
index 1980e2a28265..9a90f824814e 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h
@@ -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>
diff --git a/include/drm/drmP.h b/include/drm/drmP.h
index 761b20332321..d22ba6bf2299 100644
--- a/include/drm/drmP.h
+++ b/include/drm/drmP.h
@@ -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)
@@ -1008,11 +985,6 @@ static inline wait_queue_head_t *drm_crtc_vblank_waitqueue(struct drm_crtc *crtc
return &crtc->dev->vblank[drm_crtc_index(crtc)].queue;
}
-/* 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);
diff --git a/include/drm/drm_auth.h b/include/drm/drm_auth.h
new file mode 100644
index 000000000000..610223b0481b
--- /dev/null
+++ b/include/drm/drm_auth.h
@@ -0,0 +1,59 @@
+/*
+ * Internal Header for the Direct Rendering Manager
+ *
+ * Copyright 2016 Intel Corporation
+ *
+ * Author: Daniel Vetter <daniel.vetter at 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
diff --git a/include/drm/drm_legacy.h b/include/drm/drm_legacy.h
index a5ef2c7e40f8..cf0e7d89bcdf 100644
--- a/include/drm/drm_legacy.h
+++ b/include/drm/drm_legacy.h
@@ -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
*
--
2.8.1
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