/* * 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; extern struct lock_class_key reservation_seqcount_class; extern const char reservation_seqcount_string[]; /** * struct reservation_object_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 reservation_object_list { struct rcu_head rcu; u32 shared_count, shared_max; struct dma_fence __rcu *shared[]; }; /** * struct reservation_object - 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 reservation_object { struct ww_mutex lock; seqcount_t seq; struct dma_fence __rcu *fence_excl; struct reservation_object_list __rcu *fence; }; #define reservation_object_held(obj) lockdep_is_held(&(obj)->lock.base) #define reservation_object_assert_held(obj) \ lockdep_assert_held(&(obj)->lock.base) /** * reservation_object_init - initialize a reservation object * @obj: the reservation object */ static inline void reservation_object_init(struct reservation_object *obj) { ww_mutex_init(&obj->lock, &reservation_ww_class); __seqcount_init(&obj->seq, reservation_seqcount_string, &reservation_seqcount_class); RCU_INIT_POINTER(obj->fence, NULL); RCU_INIT_POINTER(obj->fence_excl, NULL); } /** * reservation_object_fini - destroys a reservation object * @obj: the reservation object */ static inline void reservation_object_fini(struct reservation_object *obj) { int i; struct reservation_object_list *fobj; struct dma_fence *excl; /* * This object should be dead and all references must have * been released to it, so no need to be protected with rcu. */ excl = rcu_dereference_protected(obj->fence_excl, 1); if (excl) dma_fence_put(excl); fobj = rcu_dereference_protected(obj->fence, 1); if (fobj) { for (i = 0; i < fobj->shared_count; ++i) dma_fence_put(rcu_dereference_protected(fobj->shared[i], 1)); kfree(fobj); } ww_mutex_destroy(&obj->lock); } /** * reservation_object_get_list - get the reservation object's * shared fence list, with update-side lock held * @obj: the reservation object * * Returns the shared fence list. Does NOT take references to * the fence. The obj->lock must be held. */ static inline struct reservation_object_list * reservation_object_get_list(struct reservation_object *obj) { return rcu_dereference_protected(obj->fence, reservation_object_held(obj)); } /** * reservation_object_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 reservation_object_lock(struct reservation_object *obj, struct ww_acquire_ctx *ctx) { return ww_mutex_lock(&obj->lock, ctx); } /** * reservation_object_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 reservation_object_lock_interruptible(struct reservation_object *obj, struct ww_acquire_ctx *ctx) { return ww_mutex_lock_interruptible(&obj->lock, ctx); } /** * reservation_object_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 reservation_object_trylock(struct reservation_object *obj) { return ww_mutex_trylock(&obj->lock); } /** * reservation_object_unlock - unlock the reservation object * @obj: the reservation object * * Unlocks the reservation object following exclusive access. */ static inline void reservation_object_unlock(struct reservation_object *obj) { #ifdef CONFIG_DEBUG_MUTEXES /* Test shared fence slot reservation */ if (obj->fence) obj->fence->shared_max = obj->fence->shared_count; #endif ww_mutex_unlock(&obj->lock); } /** * reservation_object_get_excl - get the reservation object's * exclusive fence, with update-side lock held * @obj: the reservation object * * Returns the exclusive fence (if any). Does NOT take a * reference. The obj->lock must be held. * * RETURNS * The exclusive fence or NULL */ static inline struct dma_fence * reservation_object_get_excl(struct reservation_object *obj) { return rcu_dereference_protected(obj->fence_excl, reservation_object_held(obj)); } /** * reservation_object_get_excl_rcu - 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 * reservation_object_get_excl_rcu(struct reservation_object *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; } int reservation_object_reserve_shared(struct reservation_object *obj, unsigned int num_fences); void reservation_object_add_shared_fence(struct reservation_object *obj, struct dma_fence *fence); void reservation_object_add_excl_fence(struct reservation_object *obj, struct dma_fence *fence); int reservation_object_get_fences_rcu(struct reservation_object *obj, struct dma_fence **pfence_excl, unsigned *pshared_count, struct dma_fence ***pshared); int reservation_object_copy_fences(struct reservation_object *dst, struct reservation_object *src); long reservation_object_wait_timeout_rcu(struct reservation_object *obj, bool wait_all, bool intr, unsigned long timeout); bool reservation_object_test_signaled_rcu(struct reservation_object *obj, bool test_all); #endif /* _LINUX_RESERVATION_H */