Re: [PATCH 11/24] drm/doc: Document drm_file.[hc]

Sean Paul
2017-03-13T17:53:32Z

On Wed, Mar 08, 2017 at 03:12:44PM +0100, Daniel Vetter wrote:
> Well, mostly drm_file.h, and clean up all related things:
>
> - I didnt' figure out the difference between preclose and postclose.
> The existing explanation in drm-internals.rst didn't convince me,
> since it's also really outdated - we clean up pending DRM events in
> the core nowadays. I put a FIXME in for the future.
>
> - Another FIXME is to have a macro for default fops.
>
> - Lots of links all around, main areas are to tie the overview in
> drm_file.c more into the callbacks in struct drm_device, and the
> other is to link render/primary node code to the right sections in
> drm-uapi.rst.
>
> - Also moved the open/close stuff to drm_drv.h from drm-internals.rst,
> seems like the better place for that information. Since that section
> was rather outdated this amounted to full-on rewrite.
>
> A big missing piece here is some overview graph, but I think better to
> wait with that one until drm_device and drm_driver are also fully
> documented.
>
> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>

Overall, awesome patch, really does a good job explaining the parameters and how
they interact with each other (bonus points for the lock breadcrumbs). I just
have a few optional nits and some spelling errors.

Reviewed-by: Sean Paul <seanpaul@chromium.org>

> ---
> Documentation/gpu/drm-internals.rst | 52 +------
> Documentation/gpu/drm-uapi.rst | 4 +
> drivers/gpu/drm/drm_file.c | 66 +++++----
> include/drm/drm_drv.h | 81 ++++++++++-
> include/drm/drm_file.h | 267 ++++++++++++++++++++++++++++++++----
> 5 files changed, 356 insertions(+), 114 deletions(-)
>
> diff --git a/Documentation/gpu/drm-internals.rst b/Documentation/gpu/drm-internals.rst
> index ea329b71c459..7a2fe4a02212 100644
> --- a/Documentation/gpu/drm-internals.rst
> +++ b/Documentation/gpu/drm-internals.rst
> @@ -246,61 +246,15 @@ drivers.
> Open/Close, File Operations and IOCTLs
> ======================================
>
> -Open and Close
> ---------------
> -
> -Open and close handlers. None of those methods are mandatory::
> -
> - int (*firstopen) (struct drm_device *);
> - void (*lastclose) (struct drm_device *);
> - int (*open) (struct drm_device *, struct drm_file *);
> - void (*preclose) (struct drm_device *, struct drm_file *);
> - void (*postclose) (struct drm_device *, struct drm_file *);
> -
> -The firstopen method is called by the DRM core for legacy UMS (User Mode
> -Setting) drivers only when an application opens a device that has no
> -other opened file handle. UMS drivers can implement it to acquire device
> -resources. KMS drivers can't use the method and must acquire resources
> -in the load method instead.
> -
> -Similarly the lastclose method is called when the last application
> -holding a file handle opened on the device closes it, for both UMS and
> -KMS drivers. Additionally, the method is also called at module unload
> -time or, for hot-pluggable devices, when the device is unplugged. The
> -firstopen and lastclose calls can thus be unbalanced.
> -
> -The open method is called every time the device is opened by an
> -application. Drivers can allocate per-file private data in this method
> -and store them in the struct :c:type:`struct drm_file
> -<drm_file>` driver_priv field. Note that the open method is
> -called before firstopen.
> -
> -The close operation is split into preclose and postclose methods.
> -Drivers must stop and cleanup all per-file operations in the preclose
> -method. For instance pending vertical blanking and page flip events must
> -be cancelled. No per-file operation is allowed on the file handle after
> -returning from the preclose method.
> -
> -Finally the postclose method is called as the last step of the close
> -operation, right before calling the lastclose method if no other open
> -file handle exists for the device. Drivers that have allocated per-file
> -private data in the open method should free it here.
> -
> -The lastclose method should restore CRTC and plane properties to default
> -value, so that a subsequent open of the device will not inherit state
> -from the previous user. It can also be used to execute delayed power
> -switching state changes, e.g. in conjunction with the :ref:`vga_switcheroo`
> -infrastructure. Beyond that KMS drivers should not do any
> -further cleanup. Only legacy UMS drivers might need to clean up device
> -state so that the vga console or an independent fbdev driver could take
> -over.
> -
> File Operations
> ---------------
>
> .. kernel-doc:: drivers/gpu/drm/drm_file.c
> :doc: file operations
>
> +.. kernel-doc:: include/drm/drm_file.h
> + :internal:
> +
> .. kernel-doc:: drivers/gpu/drm/drm_file.c
> :export:
>
> diff --git a/Documentation/gpu/drm-uapi.rst b/Documentation/gpu/drm-uapi.rst
> index fcc228ef5bc4..352652810dab 100644
> --- a/Documentation/gpu/drm-uapi.rst
> +++ b/Documentation/gpu/drm-uapi.rst
> @@ -21,6 +21,8 @@ libdrm Device Lookup
> :doc: getunique and setversion story
>
>
> +.. _drm_primary_node:
> +
> Primary Nodes, DRM Master and Authentication
> ============================================
>
> @@ -103,6 +105,8 @@ is already rather painful for the DRM subsystem, with multiple different uAPIs
> for the same thing co-existing. If we add a few more complete mistakes into the
> mix every year it would be entirely unmanageable.
>
> +.. _drm_render_node:
> +
> Render nodes
> ============
>
> diff --git a/drivers/gpu/drm/drm_file.c b/drivers/gpu/drm/drm_file.c
> index d9e63d73d3ec..a8813a1115dc 100644
> --- a/drivers/gpu/drm/drm_file.c
> +++ b/drivers/gpu/drm/drm_file.c
> @@ -50,12 +50,14 @@ DEFINE_MUTEX(drm_global_mutex);
> *
> * Drivers must define the file operations structure that forms the DRM
> * userspace API entry point, even though most of those operations are
> - * implemented in the DRM core. The mandatory functions are drm_open(),
> + * implemented in the DRM core. The resulting &struct file_operations must be
> + * stored in the &drm_driver.fops field. The mandatory functions are drm_open(),
> * drm_read(), drm_ioctl() and drm_compat_ioctl() if CONFIG_COMPAT is enabled
> - * (note that drm_compat_ioctl will be NULL if CONFIG_COMPAT=n). Drivers which
> - * implement private ioctls that require 32/64 bit compatibility support must
> - * provide their own .compat_ioctl() handler that processes private ioctls and
> - * calls drm_compat_ioctl() for core ioctls.
> + * Note that drm_compat_ioctl will be NULL if CONFIG_COMPAT=n, so there's no
> + * need to sprinkle #ifdef into the code. Drivers which implement private ioctls
> + * that require 32/64 bit compatibility support must provide their own
> + * &file_operations.compat_ioctl handler that processes private ioctls and calls
> + * drm_compat_ioctl() for core ioctls.
> *
> * In addition drm_read() and drm_poll() provide support for DRM events. DRM
> * events are a generic and extensible means to send asynchronous events to
> @@ -63,10 +65,14 @@ DEFINE_MUTEX(drm_global_mutex);
> * page flip completions by the KMS API. But drivers can also use it for their
> * own needs, e.g. to signal completion of rendering.
> *
> + * For the driver-side event interface see drm_event_reserve_init() and
> + * drm_send_event() as the main starting points.
> + *
> * The memory mapping implementation will vary depending on how the driver
> * manages memory. Legacy drivers will use the deprecated drm_legacy_mmap()
> * function, modern drivers should use one of the provided memory-manager
> - * specific implementations. For GEM-based drivers this is drm_gem_mmap().
> + * specific implementations. For GEM-based drivers this is drm_gem_mmap(), and
> + * for drivers which use the CMA GEM helpers it's drm_gem_cma_mmap().
> *
> * No other file operations are supported by the DRM userspace API. Overall the
> * following is an example #file_operations structure::
> @@ -82,6 +88,9 @@ DEFINE_MUTEX(drm_global_mutex);
> * .llseek = no_llseek,
> * .mmap = drm_gem_mmap,
> * };
> + *
> + * FIXME: We should have a macro for this (and the CMA version) so that drivers
> + * don't have to repeat it all the time.
> */
>
> static int drm_open_helper(struct file *filp, struct drm_minor *minor);
> @@ -111,9 +120,9 @@ static int drm_setup(struct drm_device * dev)
> * @inode: device inode
> * @filp: file pointer.
> *
> - * This function must be used by drivers as their .open() #file_operations
> - * method. It looks up the correct DRM device and instantiates all the per-file
> - * resources for it.
> + * This function must be used by drivers as their &file_operations.open method.
> + * It looks up the correct DRM device and instantiates all the per-file
> + * resources for it. It also calls the &drm_driver.open driver callback.
> *
> * RETURNS:
> *
> @@ -298,11 +307,6 @@ static void drm_events_release(struct drm_file *file_priv)
> spin_unlock_irqrestore(&dev->event_lock, flags);
> }
>
> -/*
> - * drm_legacy_dev_reinit
> - *
> - * Reinitializes a legacy/ums drm device in it's lastclose function.
> - */
> static void drm_legacy_dev_reinit(struct drm_device *dev)
> {
> if (dev->irq_enabled)
> @@ -327,15 +331,6 @@ static void drm_legacy_dev_reinit(struct drm_device *dev)
> DRM_DEBUG("lastclose completed\n");
> }
>
> -/*
> - * Take down the DRM device.
> - *
> - * \param dev DRM device structure.
> - *
> - * Frees every resource in \p dev.
> - *
> - * \sa drm_device
> - */
> void drm_lastclose(struct drm_device * dev)
> {
> DRM_DEBUG("\n");
> @@ -353,9 +348,11 @@ void drm_lastclose(struct drm_device * dev)
> * @inode: device inode
> * @filp: file pointer.
> *
> - * This function must be used by drivers as their .release() #file_operations
> - * method. It frees any resources associated with the open file, and if this is
> - * the last open file for the DRM device also proceeds to call drm_lastclose().
> + * This function must be used by drivers as their &file_operations.release
> + * method. It frees any resources associated with the open file, and calls the
> + * &drm_driver.preclose and &drm_driver.lastclose driver callbacks. If this is
> + * the last open file for the DRM device also proceeds to call the
> + * &drm_driver.lastclose driver callback.
> *
> * RETURNS:
> *
> @@ -443,13 +440,13 @@ EXPORT_SYMBOL(drm_release);
> * @count: count in bytes to read
> * @offset: offset to read
> *
> - * This function must be used by drivers as their .read() #file_operations
> + * This function must be used by drivers as their &file_operations.read
> * method iff they use DRM events for asynchronous signalling to userspace.
> * Since events are used by the KMS API for vblank and page flip completion this
> * means all modern display drivers must use it.
> *
> - * @offset is ignore, DRM events are read like a pipe. Therefore drivers also
> - * must set the .llseek() #file_operation to no_llseek(). Polling support is
> + * @offset is ignored, DRM events are read like a pipe. Therefore drivers also
> + * must set the &file_operation.llseek to no_llseek(). Polling support is

nit: double space before 'to'

> * provided by drm_poll().
> *
> * This function will only ever read a full event. Therefore userspace must
> @@ -537,10 +534,10 @@ EXPORT_SYMBOL(drm_read);
> * @filp: file pointer
> * @wait: poll waiter table
> *
> - * This function must be used by drivers as their .read() #file_operations
> - * method iff they use DRM events for asynchronous signalling to userspace.
> - * Since events are used by the KMS API for vblank and page flip completion this
> - * means all modern display drivers must use it.
> + * This function must be used by drivers as their &file_operations.read method
> + * iff they use DRM events for asynchronous signalling to userspace. Since
> + * events are used by the KMS API for vblank and page flip completion this means
> + * all modern display drivers must use it.
> *
> * See also drm_read().
> *
> @@ -650,7 +647,8 @@ EXPORT_SYMBOL(drm_event_reserve_init);
> * @p: tracking structure for the pending event
> *
> * This function frees the event @p initialized with drm_event_reserve_init()
> - * and releases any allocated space.
> + * and releases any allocated space. It is used to cancel an event when the
> + * nonblocking operation could not be submitted and needed to be aborted.
> */
> void drm_event_cancel_free(struct drm_device *dev,
> struct drm_pending_event *p)
> diff --git a/include/drm/drm_drv.h b/include/drm/drm_drv.h
> index 4321d012c4ba..8f900fb30275 100644
> --- a/include/drm/drm_drv.h
> +++ b/include/drm/drm_drv.h
> @@ -64,7 +64,6 @@ struct drm_mode_create_dumb;
> * structure for GEM drivers.
> */
> struct drm_driver {
> -
> /**
> * @load:
> *
> @@ -76,14 +75,94 @@ struct drm_driver {
> * See drm_dev_init() and drm_dev_register() for proper and
> * race-free way to set up a &struct drm_device.
> *
> + * This is deprecated, do not use!
> + *
> * Returns:
> *
> * Zero on success, non-zero value on failure.
> */
> int (*load) (struct drm_device *, unsigned long flags);
> +
> + /**
> + * @open:
> + *
> + * Driver callback when a new &struct drm_file is opened. Useful for
> + * setting up driver-private data structures like buffer allocators,
> + * execution contexts or similar things. Such driver-private resources
> + * must be released again in @postclose.
> + *
> + * Since the display/modeset side of DRM can only be owned by exactly
> + * one &struct drm_file (see &drm_file.is_master and &drm_device.master)
> + * there should never be a need to set up any modeset related resources
> + * in this callback. Doing so would be a driver design bug.
> + *
> + * Returns:
> + *
> + * 0 on success, a negative error code on failure, which will be
> + * promoted to userspace as the result of the open() system call.
> + */
> int (*open) (struct drm_device *, struct drm_file *);
> +
> + /**
> + * @preclose:
> + *
> + * One of the driver callbacks when a new &struct drm_file is closed.
> + * Useful for tearing down driver-private data structures allocated in
> + * @open like buffer allocators, execution contexts or similar things.
> + *
> + * Since the display/modeset side of DRM can only be owned by exactly
> + * one &struct drm_file (see &drm_file.is_master and &drm_device.master)
> + * there should never be a need to tear down any modeset related
> + * resources in this callback. Doing so would be a driver design bug.
> + *
> + * FIXME: It is not really clear why there's both @preclose and
> + * @postclose. Without a really good reason, use @postclose only.
> + */
> void (*preclose) (struct drm_device *, struct drm_file *file_priv);
> +
> + /**
> + * @postclose:
> + *
> + * One of the driver callbacks when a new &struct drm_file is closed.
> + * Useful for tearing down driver-private data structures allocated in
> + * @open like buffer allocators, execution contexts or similar things.
> + *
> + * Since the display/modeset side of DRM can only be owned by exactly
> + * one &struct drm_file (see &drm_file.is_master and &drm_device.master)
> + * there should never be a need to tear down any modeset related
> + * resources in this callback. Doing so would be a driver design bug.
> + *
> + * FIXME: It is not really clear why there's both @preclose and
> + * @postclose. Without a really good reason, use @postclose only.
> + */
> void (*postclose) (struct drm_device *, struct drm_file *);
> +
> + /**
> + * @lastclose:
> + *
> + * Called when the last &struct drm_file has been closed and there's
> + * currently no userspace client for the &struct drm_device.
> + *
> + * Modern drivers should only use this to force-restore the fbdev
> + * framebuffer using drm_fb_helper_restore_fbdev_mode_unlocked().
> + * Anything else would indicate there's something seriously wrong.
> + * Modern drivers can also use this to execute delayed power switching
> + * state changes, e.g. in conjunction with the :ref:`vga_switcheroo`
> + * infrastructure.
> + *
> + * This is called after @preclose and @postclose have been called.
> + *
> + * NOTE:
> + *
> + * All legacy drivers use this callback to de-initialize the hardware.
> + * This is purely because of the shadow-attach model, where the DRM
> + * kernel driver does not really own the hardware. Instead ownershipe is
> + * handled with the help of userspace through an inheritedly racy dance
> + * to set/unset the VT into raw mode.
> + *
> + * Legacy drivers initialize the hardware in the @firstopen callback,
> + * which isn't even called for modern drivers.
> + */
> void (*lastclose) (struct drm_device *);
>
> /**
> diff --git a/include/drm/drm_file.h b/include/drm/drm_file.h
> index 4e347399a7bd..67244f2c0c54 100644
> --- a/include/drm/drm_file.h
> +++ b/include/drm/drm_file.h
> @@ -45,6 +45,7 @@ struct drm_device;
> * FIXME: Not sure we want to have drm_minor here in the end, but to avoid
> * header include loops we need it here for now.
> */
> +
> enum drm_minor_type {
> DRM_MINOR_PRIMARY,
> DRM_MINOR_CONTROL,
> @@ -52,12 +53,19 @@ enum drm_minor_type {
> };
>
> /**
> - * DRM minor structure. This structure represents a drm minor number.
> + * struct drm_minor - DRM device minor structure
> + *
> + * This structure represents a DRM minor number for device nodes in /dev.
> + * Entirely opaque to drivers and should never be inspected directly by drivers.
> + * Drivers instead should only interact with &struct drm_file and of course
> + * &struct drm_device, which is also where driver-private data and resources can
> + * be attached to.
> */
> struct drm_minor {
> - int index; /**< Minor device number */
> - int type; /**< Control or render */
> - struct device *kdev; /**< Linux device */
> + /* private: */

Same comment here re: the private comment. I don't think it adds anything beyond
what you've already said in the overview.

> + int index; /* Minor device number */
> + int type; /* Control or render */
> + struct device *kdev; /* Linux device */
> struct drm_device *dev;
>
> struct dentry *debugfs_root;
> @@ -66,89 +74,288 @@ struct drm_minor {
> struct mutex debugfs_lock; /* Protects debugfs_list. */
> };
>
> -/* Event queued up for userspace to read */
> +/**
> + * struct drm_pending_event - Event queued up for userspace to read
> + *
> + * This represents a DRM event. Drivers can use this as a generic completion
> + * mechanism, which supports kernel-internal &struct completion, &struct dma_fence
> + * and also the DRM-specific &struct drm_event delivery mechanism.
> + */
> struct drm_pending_event {
> + /**
> + * @completion:
> + *
> + * Optional pointer to a kernel internal completion signalled when
> + * drm_send_event() is called, useful to internally synchronize with
> + * nonblcoking operations.

nonblocking

> + */
> struct completion *completion;
> +
> + /**
> + * @completion_release:
> + *
> + * Optional callback currently only used by the atomic modeset helpers
> + * to clean up the reference count for the structure @completion is
> + * stored in.
> + */
> void (*completion_release)(struct completion *completion);
> +
> + /**
> + * @event:
> + *
> + * Pointer to the actual event that should be sent to userspace to be
> + * read using drm_read(). Can be optional, since nowadays events are
> + * also used to signal kernel internal threads with @completion or DMA
> + * transactions using @fence.
> + */
> struct drm_event *event;
> +
> + /**
> + * @fence:
> + *
> + * Optional DMA fence to unblock other hardware transactions which
> + * depend upon the nonblocking DRM operation this event represents.
> + */
> struct dma_fence *fence;
> +
> + /**
> + * @file_priv:
> + *
> + * &struct drm_file where @event should be delivered to. Only set when
> + * @event is set.
> + */
> + struct drm_file *file_priv;
> +
> + /**
> + * @link:
> + *
> + * Double-linked list to keep track of this event. Can be used by the
> + * driver up to the point when it calls drm_send_event(), after that
> + * this list entry is owned by the core for its own book-keeping.
> + */
> struct list_head link;
> +
> + /**
> + * @pending_link:
> + *
> + * Entry on &drm_file.pending_event_list, to keep track of all pending
> + * events for @file_priv, to allow correct unwinding of them when
> + * userspace closes the file before the event is delivered.
> + */
> struct list_head pending_link;
> - struct drm_file *file_priv;
> };
>
> -/** File private data */
> +/**
> + * struct drm_file - DRM file private data
> + *
> + * This structure tracks per open file descriptor DRM state.

nit: This structure tracks DRM state per open file descriptor.

> + */
> struct drm_file {
> + /**
> + * @authenticated:
> + *
> + * Whether the client is allowed to submit rendering, which for legacy
> + * nodes means it must be authenticated.
> + *
> + * See also the :ref:`section on primary nodes and authentication
> + * <drm_primary_node>`.
> + */
> +

nit: extra line

> unsigned authenticated :1;
> - /* true when the client has asked us to expose stereo 3D mode flags */
> +
> + /**
> + * @stereo_allowed:
> + *
> + * True when the client has asked us to expose stereo 3D mode flags.
> + */
> unsigned stereo_allowed :1;
> - /*
> - * true if client understands CRTC primary planes and cursor planes
> - * in the plane list
> +
> + /**
> + * @universal_planes:
> + *
> + * True if client understands CRTC primary planes and cursor planes
> + * in the plane list. Automatically set when @atomic is set.
> */
> unsigned universal_planes:1;
> - /* true if client understands atomic properties */
> +
> + /** @atomic: True if client understands atomic properties. */
> unsigned atomic:1;
> - /*
> - * This client is the creator of @master.
> - * Protected by struct drm_device::master_mutex.
> +
> + /**
> + * @is_master:
> + *
> + * This client is the creator of @master. Protected by struct

nit: double space before Protected

> + * &drm_device.master_mutex.
> + *
> + * See also the :ref:`section on primary nodes and authentication
> + * <drm_primary_node>`.
> */
> unsigned is_master:1;
>
> + /**
> + * @master:
> + *
> + * Master this node is currently associated with. Only relevant if
> + * drm_is_primary_client() returns true. Note that this only
> + * matches &drm_device.master if the master is the currently active one.
> + *
> + * See also @authentication and @is_master and the :ref:`section on
> + * primary nodes and authentication <drm_primary_node>`.
> + */
> + struct drm_master *master;
> +
> + /** @pid: Process that opened this file. */
> struct pid *pid;
> +
> + /** @magic: Authentication magic, see @authenticated. */
> drm_magic_t magic;
> +
> + /**
> + * @lhead:
> + *
> + * List of all open files of a DRM device, linked into
> + * &drm_device.filelist. Protected by &drm_device.filelist_mutex.
> + */
> struct list_head lhead;
> +
> +

nit: extra line

> + /** @minor: &struct drm_minor for this file. */
> struct drm_minor *minor;
> - unsigned long lock_count;
>
> - /** Mapping of mm object handles to object pointers. */
> + /**
> + * @object_idr:
> + *
> + * Mapping of mm object handles to object pointers. Used by the GEM
> + * subsystem. Protected by @table_lock.
> + */
> struct idr object_idr;
> - /** Lock for synchronization of access to object_idr. */
> +
> + /** @table_lock: Protects @object_idr. */
> spinlock_t table_lock;
>
> + /** @filp: Pointer to the core file structure. */
> struct file *filp;
> +
> + /**
> + * @driver_priv:
> + *
> + * Optional pointer for driver private data. Can be allocated in
> + * &drm_driver.open and should be freed in &drm_driver.postclose.
> + */
> void *driver_priv;
>
> - struct drm_master *master; /* master this node is currently associated with
> - N.B. not always dev->master */
> /**
> - * fbs - List of framebuffers associated with this file.
> + * @fbs:
> + *
> + * List of &struct drm_framebuffer associated with this file, using the
> + * &drm_framebuffer.filp_head entry.
> *
> - * Protected by fbs_lock. Note that the fbs list holds a reference on
> - * the fb object to prevent it from untimely disappearing.
> + * Protected by @fbs_lock. Note that the @fbs list holds a reference on
> + * the framebuffer object to prevent it from untimely disappearing.
> */
> struct list_head fbs;
> +
> + /** @fbs_lock: Protects @fbs. */
> struct mutex fbs_lock;
>
> - /** User-created blob properties; this retains a reference on the
> - * property. */
> + /**
> + * @blobs:
> + *
> + * User-created blob properties; this retains a reference on the
> + * property.
> + *
> + * Protected by @drm_mode_config.blob_lock;
> + */
> struct list_head blobs;
>
> + /** @event_wait: Waitqueue for new events added to @event_list. */
> wait_queue_head_t event_wait;
> +
> + /**
> + * @pending_event_list:
> + *
> + * List of pending &struct drm_pending_event, used to clean up pending
> + * events in case this file gets closed before the event is signalled.
> + * Uses the &drm_pending_event.pending_link entry.
> + *
> + * Protect by &drm_device.event_lock.
> + */
> struct list_head pending_event_list;
> +
> + /**
> + * @event_list:
> + *
> + * List of &struct drm_pending_event, ready for devlivery to userspace

Dat 'dev' muscle memory :-)

> + * through drm_read(). Uses the &drm_pending_event.link entry.
> + *
> + * Protect by &drm_device.event_lock.
> + */
> struct list_head event_list;
> +
> + /**
> + * @event_space:
> + *
> + * Available event space to prevent userspace from
> + * exhausting kernel memory. Currently limited to the fairly arbitrary
> + * value of 4KB.
> + */
> int event_space;
>
> + /** @event_read_lock: Serializes drm_read(). */
> struct mutex event_read_lock;
>
> + /**
> + * @prime:
> + *
> + * Per-file buffer caches used by the PRIME buffer sharing code.
> + */
> struct drm_prime_file_private prime;
> +
> + /* private: */
> + unsigned long lock_count; /* DRI1 legacy lock count */
> };
>
> +/**
> + * drm_is_primary_client - is this an open file of the primary node
> + * @file_priv: DRM file
> + *
> + * Returns true if this is an open file of the primary node, i.e.
> + * &drm_file.minor of @file_priv is a primary minor.
> + *
> + * See also the :ref:`section on primary nodes and authentication
> + * <drm_primary_node>`.
> + */
> +static inline bool drm_is_primary_client(const struct drm_file *file_priv)
> +{
> + return file_priv->minor->type == DRM_MINOR_PRIMARY;
> +}
> +
> +/**
> + * drm_is_render_client - is this an open file of the render node
> + * @file_priv: DRM file
> + *
> + * Returns true if this is an open file of the render node, i.e.
> + * &drm_file.minor of @file_priv is a render minor.
> + *
> + * See also the :ref:`section on render nodes <drm_render_node>`.
> + */
> static inline bool drm_is_render_client(const struct drm_file *file_priv)
> {
> return file_priv->minor->type == DRM_MINOR_RENDER;
> }
>
> +/**
> + * drm_is_control_client - is this an open file of the control node
> + * @file_priv: DRM file
> + *
> + * Control nodes are deprecated and in the process of getting removed from the
> + * DRM userspace API. Do not ever use!
> + */
> static inline bool drm_is_control_client(const struct drm_file *file_priv)
> {
> return file_priv->minor->type == DRM_MINOR_CONTROL;
> }
>
> -static inline bool drm_is_primary_client(const struct drm_file *file_priv)
> -{
> - return file_priv->minor->type == DRM_MINOR_PRIMARY;
> -}
> -
> int drm_open(struct inode *inode, struct file *filp);
> ssize_t drm_read(struct file *filp, char __user *buffer,
> size_t count, loff_t *offset);
> --
> 2.11.0
>
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
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