drm_modeset_lock.h
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/*
* Copyright (C) 2014 Red Hat
* Author: Rob Clark <robdclark@gmail.com>
*
* 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 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
* THE COPYRIGHT HOLDER(S) OR AUTHOR(S) 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_MODESET_LOCK_H_
#define DRM_MODESET_LOCK_H_
#include <linux/ww_mutex.h>
struct drm_modeset_lock;
/**
* struct drm_modeset_acquire_ctx - locking context (see ww_acquire_ctx)
* @ww_ctx: base acquire ctx
* @contended: used internally for -EDEADLK handling
* @locked: list of held locks
* @trylock_only: trylock mode used in atomic contexts/panic notifiers
*
* Each thread competing for a set of locks must use one acquire
* ctx. And if any lock fxn returns -EDEADLK, it must backoff and
* retry.
*/
struct drm_modeset_acquire_ctx {
struct ww_acquire_ctx ww_ctx;
/*
* Contended lock: if a lock is contended you should only call
* drm_modeset_backoff() which drops locks and slow-locks the
* contended lock.
*/
struct drm_modeset_lock *contended;
/*
* list of held locks (drm_modeset_lock)
*/
struct list_head locked;
/*
* Trylock mode, use only for panic handlers!
*/
bool trylock_only;
};
/**
* struct drm_modeset_lock - used for locking modeset resources.
* @mutex: resource locking
* @head: used to hold it's place on state->locked list when
* part of an atomic update
*
* Used for locking CRTCs and other modeset resources.
*/
struct drm_modeset_lock {
/*
* modeset lock
*/
struct ww_mutex mutex;
/*
* Resources that are locked as part of an atomic update are added
* to a list (so we know what to unlock at the end).
*/
struct list_head head;
};
extern struct ww_class crtc_ww_class;
void drm_modeset_acquire_init(struct drm_modeset_acquire_ctx *ctx,
uint32_t flags);
void drm_modeset_acquire_fini(struct drm_modeset_acquire_ctx *ctx);
void drm_modeset_drop_locks(struct drm_modeset_acquire_ctx *ctx);
void drm_modeset_backoff(struct drm_modeset_acquire_ctx *ctx);
int drm_modeset_backoff_interruptible(struct drm_modeset_acquire_ctx *ctx);
/**
* drm_modeset_lock_init - initialize lock
* @lock: lock to init
*/
static inline void drm_modeset_lock_init(struct drm_modeset_lock *lock)
{
ww_mutex_init(&lock->mutex, &crtc_ww_class);
INIT_LIST_HEAD(&lock->head);
}
/**
* drm_modeset_lock_fini - cleanup lock
* @lock: lock to cleanup
*/
static inline void drm_modeset_lock_fini(struct drm_modeset_lock *lock)
{
WARN_ON(!list_empty(&lock->head));
}
/**
* drm_modeset_is_locked - equivalent to mutex_is_locked()
* @lock: lock to check
*/
static inline bool drm_modeset_is_locked(struct drm_modeset_lock *lock)
{
return ww_mutex_is_locked(&lock->mutex);
}
int drm_modeset_lock(struct drm_modeset_lock *lock,
struct drm_modeset_acquire_ctx *ctx);
int drm_modeset_lock_interruptible(struct drm_modeset_lock *lock,
struct drm_modeset_acquire_ctx *ctx);
void drm_modeset_unlock(struct drm_modeset_lock *lock);
struct drm_device;
struct drm_crtc;
struct drm_plane;
void drm_modeset_lock_all(struct drm_device *dev);
void drm_modeset_unlock_all(struct drm_device *dev);
void drm_modeset_lock_crtc(struct drm_crtc *crtc,
struct drm_plane *plane);
void drm_modeset_unlock_crtc(struct drm_crtc *crtc);
void drm_warn_on_modeset_not_all_locked(struct drm_device *dev);
struct drm_modeset_acquire_ctx *
drm_modeset_legacy_acquire_ctx(struct drm_crtc *crtc);
int drm_modeset_lock_all_ctx(struct drm_device *dev,
struct drm_modeset_acquire_ctx *ctx);
#endif /* DRM_MODESET_LOCK_H_ */