/* * Header file for reservations for dma-buf and ttm * * Copyright(C) 2011 Linaro Limited. All rights reserved. * Copyright (C) 2012-2013 Canonical Ltd * Copyright (C) 2012 Texas Instruments * * Authors: * Rob Clark * Maarten Lankhorst * Thomas Hellstrom * * Based on bo.c which bears the following copyright notice, * but is dual licensed: * * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA * All Rights Reserved. * * 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, sub license, 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 (including the * next paragraph) 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 NON-INFRINGEMENT. IN NO EVENT SHALL * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS 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 _LINUX_RESERVATION_H #define _LINUX_RESERVATION_H #include #include #include #include #include extern struct ww_class reservation_ww_class; /** * struct dma_resv_list - a list of shared fences * @rcu: for internal use * @shared_count: table of shared fences * @shared_max: for growing shared fence table * @shared: shared fence table */ struct dma_resv_list { struct rcu_head rcu; u32 shared_count, shared_max; struct dma_fence __rcu *shared[]; }; /** * struct dma_resv - a reservation object manages fences for a buffer * @lock: update side lock * @seq: sequence count for managing RCU read-side synchronization * @fence_excl: the exclusive fence, if there is one currently * @fence: list of current shared fences */ struct dma_resv { struct ww_mutex lock; seqcount_ww_mutex_t seq; struct dma_fence __rcu *fence_excl; struct dma_resv_list __rcu *fence; }; #define dma_resv_held(obj) lockdep_is_held(&(obj)->lock.base) #define dma_resv_assert_held(obj) lockdep_assert_held(&(obj)->lock.base) #ifdef CONFIG_DEBUG_MUTEXES void dma_resv_reset_shared_max(struct dma_resv *obj); #else static inline void dma_resv_reset_shared_max(struct dma_resv *obj) {} #endif /** * dma_resv_lock - lock the reservation object * @obj: the reservation object * @ctx: the locking context * * Locks the reservation object for exclusive access and modification. Note, * that the lock is only against other writers, readers will run concurrently * with a writer under RCU. The seqlock is used to notify readers if they * overlap with a writer. * * As the reservation object may be locked by multiple parties in an * undefined order, a #ww_acquire_ctx is passed to unwind if a cycle * is detected. See ww_mutex_lock() and ww_acquire_init(). A reservation * object may be locked by itself by passing NULL as @ctx. */ static inline int dma_resv_lock(struct dma_resv *obj, struct ww_acquire_ctx *ctx) { return ww_mutex_lock(&obj->lock, ctx); } /** * dma_resv_lock_interruptible - lock the reservation object * @obj: the reservation object * @ctx: the locking context * * Locks the reservation object interruptible for exclusive access and * modification. Note, that the lock is only against other writers, readers * will run concurrently with a writer under RCU. The seqlock is used to * notify readers if they overlap with a writer. * * As the reservation object may be locked by multiple parties in an * undefined order, a #ww_acquire_ctx is passed to unwind if a cycle * is detected. See ww_mutex_lock() and ww_acquire_init(). A reservation * object may be locked by itself by passing NULL as @ctx. */ static inline int dma_resv_lock_interruptible(struct dma_resv *obj, struct ww_acquire_ctx *ctx) { return ww_mutex_lock_interruptible(&obj->lock, ctx); } /** * dma_resv_lock_slow - slowpath lock the reservation object * @obj: the reservation object * @ctx: the locking context * * Acquires the reservation object after a die case. This function * will sleep until the lock becomes available. See dma_resv_lock() as * well. */ static inline void dma_resv_lock_slow(struct dma_resv *obj, struct ww_acquire_ctx *ctx) { ww_mutex_lock_slow(&obj->lock, ctx); } /** * dma_resv_lock_slow_interruptible - slowpath lock the reservation * object, interruptible * @obj: the reservation object * @ctx: the locking context * * Acquires the reservation object interruptible after a die case. This function * will sleep until the lock becomes available. See * dma_resv_lock_interruptible() as well. */ static inline int dma_resv_lock_slow_interruptible(struct dma_resv *obj, struct ww_acquire_ctx *ctx) { return ww_mutex_lock_slow_interruptible(&obj->lock, ctx); } /** * dma_resv_trylock - trylock the reservation object * @obj: the reservation object * * Tries to lock the reservation object for exclusive access and modification. * Note, that the lock is only against other writers, readers will run * concurrently with a writer under RCU. The seqlock is used to notify readers * if they overlap with a writer. * * Also note that since no context is provided, no deadlock protection is * possible. * * Returns true if the lock was acquired, false otherwise. */ static inline bool __must_check dma_resv_trylock(struct dma_resv *obj) { return ww_mutex_trylock(&obj->lock); } /** * dma_resv_is_locked - is the reservation object locked * @obj: the reservation object * * Returns true if the mutex is locked, false if unlocked. */ static inline bool dma_resv_is_locked(struct dma_resv *obj) { return ww_mutex_is_locked(&obj->lock); } /** * dma_resv_locking_ctx - returns the context used to lock the object * @obj: the reservation object * * Returns the context used to lock a reservation object or NULL if no context * was used or the object is not locked at all. */ static inline struct ww_acquire_ctx *dma_resv_locking_ctx(struct dma_resv *obj) { return READ_ONCE(obj->lock.ctx); } /** * dma_resv_unlock - unlock the reservation object * @obj: the reservation object * * Unlocks the reservation object following exclusive access. */ static inline void dma_resv_unlock(struct dma_resv *obj) { dma_resv_reset_shared_max(obj); ww_mutex_unlock(&obj->lock); } /** * dma_resv_excl_fence - return the object's exclusive fence * @obj: the reservation object * * Returns the exclusive fence (if any). Caller must either hold the objects * through dma_resv_lock() or the RCU read side lock through rcu_read_lock(), * or one of the variants of each * * RETURNS * The exclusive fence or NULL */ static inline struct dma_fence * dma_resv_excl_fence(struct dma_resv *obj) { return rcu_dereference_check(obj->fence_excl, dma_resv_held(obj)); } /** * dma_resv_get_excl_unlocked - get the reservation object's * exclusive fence, without lock held. * @obj: the reservation object * * If there is an exclusive fence, this atomically increments it's * reference count and returns it. * * RETURNS * The exclusive fence or NULL if none */ static inline struct dma_fence * dma_resv_get_excl_unlocked(struct dma_resv *obj) { struct dma_fence *fence; if (!rcu_access_pointer(obj->fence_excl)) return NULL; rcu_read_lock(); fence = dma_fence_get_rcu_safe(&obj->fence_excl); rcu_read_unlock(); return fence; } /** * dma_resv_shared_list - get the reservation object's shared fence list * @obj: the reservation object * * Returns the shared fence list. Caller must either hold the objects * through dma_resv_lock() or the RCU read side lock through rcu_read_lock(), * or one of the variants of each */ static inline struct dma_resv_list *dma_resv_shared_list(struct dma_resv *obj) { return rcu_dereference_check(obj->fence, dma_resv_held(obj)); } void dma_resv_init(struct dma_resv *obj); void dma_resv_fini(struct dma_resv *obj); int dma_resv_reserve_shared(struct dma_resv *obj, unsigned int num_fences); void dma_resv_add_shared_fence(struct dma_resv *obj, struct dma_fence *fence); void dma_resv_add_excl_fence(struct dma_resv *obj, struct dma_fence *fence); int dma_resv_get_fences(struct dma_resv *obj, struct dma_fence **pfence_excl, unsigned *pshared_count, struct dma_fence ***pshared); int dma_resv_copy_fences(struct dma_resv *dst, struct dma_resv *src); long dma_resv_wait_timeout(struct dma_resv *obj, bool wait_all, bool intr, unsigned long timeout); bool dma_resv_test_signaled(struct dma_resv *obj, bool test_all); #endif /* _LINUX_RESERVATION_H */