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- /*
- * 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 <robdclark@gmail.com>
- * Maarten Lankhorst <maarten.lankhorst@canonical.com>
- * Thomas Hellstrom <thellstrom-at-vmware-dot-com>
- *
- * 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 <linux/ww_mutex.h>
- #include <linux/dma-fence.h>
- #include <linux/slab.h>
- #include <linux/seqlock.h>
- #include <linux/rcupdate.h>
- 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)
- /**
- * dma_resv_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 dma_resv_list *dma_resv_get_list(struct dma_resv *obj)
- {
- return rcu_dereference_protected(obj->fence,
- dma_resv_held(obj));
- }
- /**
- * 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)
- {
- #ifdef CONFIG_DEBUG_MUTEXES
- /* Test shared fence slot reservation */
- if (rcu_access_pointer(obj->fence)) {
- struct dma_resv_list *fence = dma_resv_get_list(obj);
- fence->shared_max = fence->shared_count;
- }
- #endif
- ww_mutex_unlock(&obj->lock);
- }
- /**
- * dma_resv_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. Writers must hold obj->lock, readers may only
- * hold a RCU read side lock.
- *
- * RETURNS
- * The exclusive fence or NULL
- */
- static inline struct dma_fence *
- dma_resv_get_excl(struct dma_resv *obj)
- {
- return rcu_dereference_protected(obj->fence_excl,
- dma_resv_held(obj));
- }
- /**
- * dma_resv_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 *
- dma_resv_get_excl_rcu(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;
- }
- 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_rcu(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_rcu(struct dma_resv *obj, bool wait_all, bool intr,
- unsigned long timeout);
- bool dma_resv_test_signaled_rcu(struct dma_resv *obj, bool test_all);
- #endif /* _LINUX_RESERVATION_H */
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