mirror of https://github.com/Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
206 lines
6.8 KiB
206 lines
6.8 KiB
/* |
|
* Copyright (C) 2014 Red Hat |
|
* Author: Rob Clark <[email protected]> |
|
* |
|
* 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 |
|
* @interruptible: whether interruptible locking should be used. |
|
* |
|
* 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; |
|
|
|
/* Perform interruptible waits on this context. */ |
|
bool interruptible; |
|
}; |
|
|
|
/** |
|
* struct drm_modeset_lock - used for locking modeset resources. |
|
* @mutex: resource locking |
|
* @head: used to hold its place on &drm_atomi_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; |
|
}; |
|
|
|
#define DRM_MODESET_ACQUIRE_INTERRUPTIBLE BIT(0) |
|
|
|
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); |
|
int drm_modeset_backoff(struct drm_modeset_acquire_ctx *ctx); |
|
|
|
void drm_modeset_lock_init(struct drm_modeset_lock *lock); |
|
|
|
/** |
|
* 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); |
|
} |
|
|
|
/** |
|
* drm_modeset_lock_assert_held - equivalent to lockdep_assert_held() |
|
* @lock: lock to check |
|
*/ |
|
static inline void drm_modeset_lock_assert_held(struct drm_modeset_lock *lock) |
|
{ |
|
lockdep_assert_held(&lock->mutex.base); |
|
} |
|
|
|
int drm_modeset_lock(struct drm_modeset_lock *lock, |
|
struct drm_modeset_acquire_ctx *ctx); |
|
int __must_check drm_modeset_lock_single_interruptible(struct drm_modeset_lock *lock); |
|
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_warn_on_modeset_not_all_locked(struct drm_device *dev); |
|
|
|
int drm_modeset_lock_all_ctx(struct drm_device *dev, |
|
struct drm_modeset_acquire_ctx *ctx); |
|
|
|
/** |
|
* DRM_MODESET_LOCK_ALL_BEGIN - Helper to acquire modeset locks |
|
* @dev: drm device |
|
* @ctx: local modeset acquire context, will be dereferenced |
|
* @flags: DRM_MODESET_ACQUIRE_* flags to pass to drm_modeset_acquire_init() |
|
* @ret: local ret/err/etc variable to track error status |
|
* |
|
* Use these macros to simplify grabbing all modeset locks using a local |
|
* context. This has the advantage of reducing boilerplate, but also properly |
|
* checking return values where appropriate. |
|
* |
|
* Any code run between BEGIN and END will be holding the modeset locks. |
|
* |
|
* This must be paired with DRM_MODESET_LOCK_ALL_END(). We will jump back and |
|
* forth between the labels on deadlock and error conditions. |
|
* |
|
* Drivers can acquire additional modeset locks. If any lock acquisition |
|
* fails, the control flow needs to jump to DRM_MODESET_LOCK_ALL_END() with |
|
* the @ret parameter containing the return value of drm_modeset_lock(). |
|
* |
|
* Returns: |
|
* The only possible value of ret immediately after DRM_MODESET_LOCK_ALL_BEGIN() |
|
* is 0, so no error checking is necessary |
|
*/ |
|
#define DRM_MODESET_LOCK_ALL_BEGIN(dev, ctx, flags, ret) \ |
|
if (!drm_drv_uses_atomic_modeset(dev)) \ |
|
mutex_lock(&dev->mode_config.mutex); \ |
|
drm_modeset_acquire_init(&ctx, flags); \ |
|
modeset_lock_retry: \ |
|
ret = drm_modeset_lock_all_ctx(dev, &ctx); \ |
|
if (ret) \ |
|
goto modeset_lock_fail; |
|
|
|
/** |
|
* DRM_MODESET_LOCK_ALL_END - Helper to release and cleanup modeset locks |
|
* @dev: drm device |
|
* @ctx: local modeset acquire context, will be dereferenced |
|
* @ret: local ret/err/etc variable to track error status |
|
* |
|
* The other side of DRM_MODESET_LOCK_ALL_BEGIN(). It will bounce back to BEGIN |
|
* if ret is -EDEADLK. |
|
* |
|
* It's important that you use the same ret variable for begin and end so |
|
* deadlock conditions are properly handled. |
|
* |
|
* Returns: |
|
* ret will be untouched unless it is -EDEADLK on entry. That means that if you |
|
* successfully acquire the locks, ret will be whatever your code sets it to. If |
|
* there is a deadlock or other failure with acquire or backoff, ret will be set |
|
* to that failure. In both of these cases the code between BEGIN/END will not |
|
* be run, so the failure will reflect the inability to grab the locks. |
|
*/ |
|
#define DRM_MODESET_LOCK_ALL_END(dev, ctx, ret) \ |
|
modeset_lock_fail: \ |
|
if (ret == -EDEADLK) { \ |
|
ret = drm_modeset_backoff(&ctx); \ |
|
if (!ret) \ |
|
goto modeset_lock_retry; \ |
|
} \ |
|
drm_modeset_drop_locks(&ctx); \ |
|
drm_modeset_acquire_fini(&ctx); \ |
|
if (!drm_drv_uses_atomic_modeset(dev)) \ |
|
mutex_unlock(&dev->mode_config.mutex); |
|
|
|
#endif /* DRM_MODESET_LOCK_H_ */
|
|
|