207 lines
6.8 KiB
C
207 lines
6.8 KiB
C
/*
|
|
* 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
|
|
* @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_ */
|