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294 lines
9.1 KiB
294 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 <robdclark@gmail.com>
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* Maarten Lankhorst <maarten.lankhorst@canonical.com>
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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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