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293 lines
9.1 KiB
293 lines
9.1 KiB
/* |
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* Header file for reservations for dma-buf and ttm |
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* |
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* Copyright(C) 2011 Linaro Limited. All rights reserved. |
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* Copyright (C) 2012-2013 Canonical Ltd |
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* Copyright (C) 2012 Texas Instruments |
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* |
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* Authors: |
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* Rob Clark <[email protected]> |
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* Maarten Lankhorst <[email protected]> |
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* Thomas Hellstrom <thellstrom-at-vmware-dot-com> |
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* |
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* Based on bo.c which bears the following copyright notice, |
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* but is dual licensed: |
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* |
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* Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA |
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* All Rights Reserved. |
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* |
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* Permission is hereby granted, free of charge, to any person obtaining a |
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* copy of this software and associated documentation files (the |
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* "Software"), to deal in the Software without restriction, including |
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* without limitation the rights to use, copy, modify, merge, publish, |
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* distribute, sub license, and/or sell copies of the Software, and to |
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* permit persons to whom the Software is furnished to do so, subject to |
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* the following conditions: |
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* |
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* The above copyright notice and this permission notice (including the |
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* next paragraph) shall be included in all copies or substantial portions |
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* of the Software. |
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* |
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
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* FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL |
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* THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, |
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* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR |
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* OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE |
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* USE OR OTHER DEALINGS IN THE SOFTWARE. |
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*/ |
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#ifndef _LINUX_RESERVATION_H |
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#define _LINUX_RESERVATION_H |
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#include <linux/ww_mutex.h> |
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#include <linux/dma-fence.h> |
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#include <linux/slab.h> |
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#include <linux/seqlock.h> |
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#include <linux/rcupdate.h> |
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extern struct ww_class reservation_ww_class; |
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/** |
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* struct dma_resv_list - a list of shared fences |
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* @rcu: for internal use |
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* @shared_count: table of shared fences |
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* @shared_max: for growing shared fence table |
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* @shared: shared fence table |
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*/ |
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struct dma_resv_list { |
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struct rcu_head rcu; |
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u32 shared_count, shared_max; |
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struct dma_fence __rcu *shared[]; |
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}; |
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/** |
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* struct dma_resv - a reservation object manages fences for a buffer |
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* @lock: update side lock |
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* @seq: sequence count for managing RCU read-side synchronization |
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* @fence_excl: the exclusive fence, if there is one currently |
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* @fence: list of current shared fences |
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*/ |
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struct dma_resv { |
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struct ww_mutex lock; |
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seqcount_ww_mutex_t seq; |
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struct dma_fence __rcu *fence_excl; |
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struct dma_resv_list __rcu *fence; |
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}; |
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#define dma_resv_held(obj) lockdep_is_held(&(obj)->lock.base) |
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#define dma_resv_assert_held(obj) lockdep_assert_held(&(obj)->lock.base) |
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/** |
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* dma_resv_get_list - get the reservation object's |
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* shared fence list, with update-side lock held |
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* @obj: the reservation object |
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* |
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* Returns the shared fence list. Does NOT take references to |
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* the fence. The obj->lock must be held. |
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*/ |
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static inline struct dma_resv_list *dma_resv_get_list(struct dma_resv *obj) |
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{ |
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return rcu_dereference_protected(obj->fence, |
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dma_resv_held(obj)); |
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} |
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/** |
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* dma_resv_lock - lock the reservation object |
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* @obj: the reservation object |
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* @ctx: the locking context |
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* |
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* Locks the reservation object for exclusive access and modification. Note, |
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* that the lock is only against other writers, readers will run concurrently |
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* with a writer under RCU. The seqlock is used to notify readers if they |
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* overlap with a writer. |
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* |
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* As the reservation object may be locked by multiple parties in an |
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* undefined order, a #ww_acquire_ctx is passed to unwind if a cycle |
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* is detected. See ww_mutex_lock() and ww_acquire_init(). A reservation |
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* object may be locked by itself by passing NULL as @ctx. |
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*/ |
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static inline int dma_resv_lock(struct dma_resv *obj, |
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struct ww_acquire_ctx *ctx) |
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{ |
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return ww_mutex_lock(&obj->lock, ctx); |
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} |
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/** |
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* dma_resv_lock_interruptible - lock the reservation object |
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* @obj: the reservation object |
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* @ctx: the locking context |
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* |
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* Locks the reservation object interruptible for exclusive access and |
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* modification. Note, that the lock is only against other writers, readers |
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* will run concurrently with a writer under RCU. The seqlock is used to |
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* notify readers if they overlap with a writer. |
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* |
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* As the reservation object may be locked by multiple parties in an |
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* undefined order, a #ww_acquire_ctx is passed to unwind if a cycle |
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* is detected. See ww_mutex_lock() and ww_acquire_init(). A reservation |
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* object may be locked by itself by passing NULL as @ctx. |
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*/ |
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static inline int dma_resv_lock_interruptible(struct dma_resv *obj, |
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struct ww_acquire_ctx *ctx) |
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{ |
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return ww_mutex_lock_interruptible(&obj->lock, ctx); |
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} |
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/** |
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* dma_resv_lock_slow - slowpath lock the reservation object |
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* @obj: the reservation object |
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* @ctx: the locking context |
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* |
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* Acquires the reservation object after a die case. This function |
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* will sleep until the lock becomes available. See dma_resv_lock() as |
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* well. |
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*/ |
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static inline void dma_resv_lock_slow(struct dma_resv *obj, |
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struct ww_acquire_ctx *ctx) |
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{ |
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ww_mutex_lock_slow(&obj->lock, ctx); |
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} |
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/** |
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* dma_resv_lock_slow_interruptible - slowpath lock the reservation |
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* object, interruptible |
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* @obj: the reservation object |
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* @ctx: the locking context |
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* |
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* Acquires the reservation object interruptible after a die case. This function |
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* will sleep until the lock becomes available. See |
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* dma_resv_lock_interruptible() as well. |
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*/ |
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static inline int dma_resv_lock_slow_interruptible(struct dma_resv *obj, |
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struct ww_acquire_ctx *ctx) |
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{ |
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return ww_mutex_lock_slow_interruptible(&obj->lock, ctx); |
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} |
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/** |
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* dma_resv_trylock - trylock the reservation object |
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* @obj: the reservation object |
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* |
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* Tries to lock the reservation object for exclusive access and modification. |
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* Note, that the lock is only against other writers, readers will run |
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* concurrently with a writer under RCU. The seqlock is used to notify readers |
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* if they overlap with a writer. |
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* |
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* Also note that since no context is provided, no deadlock protection is |
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* possible. |
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* |
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* Returns true if the lock was acquired, false otherwise. |
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*/ |
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static inline bool __must_check dma_resv_trylock(struct dma_resv *obj) |
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{ |
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return ww_mutex_trylock(&obj->lock); |
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} |
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/** |
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* dma_resv_is_locked - is the reservation object locked |
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* @obj: the reservation object |
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* |
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* Returns true if the mutex is locked, false if unlocked. |
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*/ |
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static inline bool dma_resv_is_locked(struct dma_resv *obj) |
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{ |
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return ww_mutex_is_locked(&obj->lock); |
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} |
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/** |
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* dma_resv_locking_ctx - returns the context used to lock the object |
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* @obj: the reservation object |
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* |
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* Returns the context used to lock a reservation object or NULL if no context |
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* was used or the object is not locked at all. |
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*/ |
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static inline struct ww_acquire_ctx *dma_resv_locking_ctx(struct dma_resv *obj) |
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{ |
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return READ_ONCE(obj->lock.ctx); |
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} |
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/** |
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* dma_resv_unlock - unlock the reservation object |
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* @obj: the reservation object |
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* |
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* Unlocks the reservation object following exclusive access. |
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*/ |
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static inline void dma_resv_unlock(struct dma_resv *obj) |
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{ |
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#ifdef CONFIG_DEBUG_MUTEXES |
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/* Test shared fence slot reservation */ |
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if (rcu_access_pointer(obj->fence)) { |
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struct dma_resv_list *fence = dma_resv_get_list(obj); |
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fence->shared_max = fence->shared_count; |
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} |
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#endif |
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ww_mutex_unlock(&obj->lock); |
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} |
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/** |
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* dma_resv_get_excl - get the reservation object's |
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* exclusive fence, with update-side lock held |
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* @obj: the reservation object |
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* |
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* Returns the exclusive fence (if any). Does NOT take a |
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* reference. Writers must hold obj->lock, readers may only |
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* hold a RCU read side lock. |
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* |
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* RETURNS |
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* The exclusive fence or NULL |
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*/ |
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static inline struct dma_fence * |
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dma_resv_get_excl(struct dma_resv *obj) |
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{ |
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return rcu_dereference_protected(obj->fence_excl, |
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dma_resv_held(obj)); |
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} |
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/** |
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* dma_resv_get_excl_rcu - get the reservation object's |
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* exclusive fence, without lock held. |
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* @obj: the reservation object |
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* |
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* If there is an exclusive fence, this atomically increments it's |
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* reference count and returns it. |
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* |
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* RETURNS |
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* The exclusive fence or NULL if none |
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*/ |
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static inline struct dma_fence * |
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dma_resv_get_excl_rcu(struct dma_resv *obj) |
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{ |
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struct dma_fence *fence; |
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if (!rcu_access_pointer(obj->fence_excl)) |
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return NULL; |
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rcu_read_lock(); |
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fence = dma_fence_get_rcu_safe(&obj->fence_excl); |
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rcu_read_unlock(); |
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return fence; |
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} |
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void dma_resv_init(struct dma_resv *obj); |
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void dma_resv_fini(struct dma_resv *obj); |
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int dma_resv_reserve_shared(struct dma_resv *obj, unsigned int num_fences); |
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void dma_resv_add_shared_fence(struct dma_resv *obj, struct dma_fence *fence); |
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void dma_resv_add_excl_fence(struct dma_resv *obj, struct dma_fence *fence); |
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int dma_resv_get_fences_rcu(struct dma_resv *obj, |
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struct dma_fence **pfence_excl, |
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unsigned *pshared_count, |
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struct dma_fence ***pshared); |
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int dma_resv_copy_fences(struct dma_resv *dst, struct dma_resv *src); |
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long dma_resv_wait_timeout_rcu(struct dma_resv *obj, bool wait_all, bool intr, |
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unsigned long timeout); |
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bool dma_resv_test_signaled_rcu(struct dma_resv *obj, bool test_all); |
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#endif /* _LINUX_RESERVATION_H */
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