/* * 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/types.h> /* stackdepot.h is not self-contained */ #include <linux/stackdepot.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 * @stack_depot: used internally for contention debugging * @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 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 { … }; #define DRM_MODESET_ACQUIRE_INTERRUPTIBLE … 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) { … } /** * 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) { … } /** * 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) { … } 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) … /** * 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) … #endif /* DRM_MODESET_LOCK_H_ */
Codebase Browser
linux