[linux-2.6-block.git] / include / linux / reservation.h

/*
 * 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;
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. 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 *
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 */
Commit	Line	Data
786d7257 ML	1	/*
	2	* Header file for reservations for dma-buf and ttm
	3	*
	4	* Copyright(C) 2011 Linaro Limited. All rights reserved.
	5	* Copyright (C) 2012-2013 Canonical Ltd
	6	* Copyright (C) 2012 Texas Instruments
	7	*
	8	* Authors:
0ba6b8fb	9	* Rob Clark <robdclark@gmail.com>
786d7257 ML	10	* Maarten Lankhorst <maarten.lankhorst@canonical.com>
	11	* Thomas Hellstrom <thellstrom-at-vmware-dot-com>
	12	*
	13	* Based on bo.c which bears the following copyright notice,
	14	* but is dual licensed:
	15	*
	16	* Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
	17	* All Rights Reserved.
	18	*
	19	* Permission is hereby granted, free of charge, to any person obtaining a
	20	* copy of this software and associated documentation files (the
	21	* "Software"), to deal in the Software without restriction, including
	22	* without limitation the rights to use, copy, modify, merge, publish,
	23	* distribute, sub license, and/or sell copies of the Software, and to
	24	* permit persons to whom the Software is furnished to do so, subject to
	25	* the following conditions:
	26	*
	27	* The above copyright notice and this permission notice (including the
	28	* next paragraph) shall be included in all copies or substantial portions
	29	* of the Software.
	30	*
	31	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	32	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	33	* FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
	34	* THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
	35	* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
	36	* OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
	37	* USE OR OTHER DEALINGS IN THE SOFTWARE.
	38	*/
	39	#ifndef _LINUX_RESERVATION_H
	40	#define _LINUX_RESERVATION_H
	41
1b375dc3	42	#include <linux/ww_mutex.h>
f54d1867	43	#include <linux/dma-fence.h>
0ba6b8fb	44	#include <linux/slab.h>
3c3b177a ML	45	#include <linux/seqlock.h>
3c3b177a ML	46	#include <linux/rcupdate.h>
786d7257 ML	47
786d7257 ML	48	extern struct ww_class reservation_ww_class;
3c3b177a ML	49	extern struct lock_class_key reservation_seqcount_class;
3c3b177a ML	50	extern const char reservation_seqcount_string[];
786d7257	51
dad6c394 RC	52	/**
	53	* struct reservation_object_list - a list of shared fences
	54	* @rcu: for internal use
	55	* @shared_count: table of shared fences
	56	* @shared_max: for growing shared fence table
	57	* @shared: shared fence table
	58	*/
04a5faa8	59	struct reservation_object_list {
3c3b177a	60	struct rcu_head rcu;
04a5faa8	61	u32 shared_count, shared_max;
f54d1867	62	struct dma_fence __rcu *shared[];
04a5faa8 ML	63	};
04a5faa8 ML	64
dad6c394 RC	65	/**
	66	* struct reservation_object - a reservation object manages fences for a buffer
	67	* @lock: update side lock
	68	* @seq: sequence count for managing RCU read-side synchronization
	69	* @fence_excl: the exclusive fence, if there is one currently
	70	* @fence: list of current shared fences
dad6c394	71	*/
786d7257 ML	72	struct reservation_object {
786d7257 ML	73	struct ww_mutex lock;
3c3b177a	74	seqcount_t seq;
0ba6b8fb	75
f54d1867	76	struct dma_fence __rcu *fence_excl;
3c3b177a	77	struct reservation_object_list __rcu *fence;
786d7257 ML	78	};
786d7257 ML	79
3c3b177a	80	#define reservation_object_held(obj) lockdep_is_held(&(obj)->lock.base)
04a5faa8 ML	81	#define reservation_object_assert_held(obj) \
	82	lockdep_assert_held(&(obj)->lock.base)
	83
dad6c394 RC	84	/**
	85	* reservation_object_init - initialize a reservation object
	86	* @obj: the reservation object
	87	*/
786d7257 ML	88	static inline void
	89	reservation_object_init(struct reservation_object *obj)
	90	{
	91	ww_mutex_init(&obj->lock, &reservation_ww_class);
0ba6b8fb	92
3c3b177a ML	93	__seqcount_init(&obj->seq, reservation_seqcount_string, &reservation_seqcount_class);
	94	RCU_INIT_POINTER(obj->fence, NULL);
	95	RCU_INIT_POINTER(obj->fence_excl, NULL);
786d7257 ML	96	}
786d7257 ML	97
dad6c394 RC	98	/**
	99	* reservation_object_fini - destroys a reservation object
	100	* @obj: the reservation object
	101	*/
786d7257 ML	102	static inline void
	103	reservation_object_fini(struct reservation_object *obj)
	104	{
0ba6b8fb	105	int i;
04a5faa8	106	struct reservation_object_list *fobj;
f54d1867	107	struct dma_fence *excl;
0ba6b8fb	108
04a5faa8 ML	109	/*
04a5faa8 ML	110	* This object should be dead and all references must have
3c3b177a	111	* been released to it, so no need to be protected with rcu.
04a5faa8	112	*/
3c3b177a ML	113	excl = rcu_dereference_protected(obj->fence_excl, 1);
3c3b177a ML	114	if (excl)
f54d1867	115	dma_fence_put(excl);
04a5faa8	116
3c3b177a	117	fobj = rcu_dereference_protected(obj->fence, 1);
04a5faa8 ML	118	if (fobj) {
04a5faa8 ML	119	for (i = 0; i < fobj->shared_count; ++i)
f54d1867	120	dma_fence_put(rcu_dereference_protected(fobj->shared[i], 1));
04a5faa8 ML	121
	122	kfree(fobj);
	123	}
0ba6b8fb	124
786d7257 ML	125	ww_mutex_destroy(&obj->lock);
	126	}
	127
dad6c394 RC	128	/**
	129	* reservation_object_get_list - get the reservation object's
	130	* shared fence list, with update-side lock held
	131	* @obj: the reservation object
	132	*
	133	* Returns the shared fence list. Does NOT take references to
	134	* the fence. The obj->lock must be held.
	135	*/
04a5faa8 ML	136	static inline struct reservation_object_list *
	137	reservation_object_get_list(struct reservation_object *obj)
	138	{
3c3b177a ML	139	return rcu_dereference_protected(obj->fence,
3c3b177a ML	140	reservation_object_held(obj));
04a5faa8 ML	141	}
04a5faa8 ML	142
122020af CW	143	/**
	144	* reservation_object_lock - lock the reservation object
	145	* @obj: the reservation object
	146	* @ctx: the locking context
	147	*
	148	* Locks the reservation object for exclusive access and modification. Note,
	149	* that the lock is only against other writers, readers will run concurrently
	150	* with a writer under RCU. The seqlock is used to notify readers if they
	151	* overlap with a writer.
	152	*
	153	* As the reservation object may be locked by multiple parties in an
	154	* undefined order, a #ww_acquire_ctx is passed to unwind if a cycle
	155	* is detected. See ww_mutex_lock() and ww_acquire_init(). A reservation
	156	* object may be locked by itself by passing NULL as @ctx.
	157	*/
	158	static inline int
	159	reservation_object_lock(struct reservation_object *obj,
	160	struct ww_acquire_ctx *ctx)
	161	{
	162	return ww_mutex_lock(&obj->lock, ctx);
	163	}
	164
5d276a1a CK	165	/**
	166	* reservation_object_lock_interruptible - lock the reservation object
	167	* @obj: the reservation object
	168	* @ctx: the locking context
	169	*
	170	* Locks the reservation object interruptible for exclusive access and
	171	* modification. Note, that the lock is only against other writers, readers
	172	* will run concurrently with a writer under RCU. The seqlock is used to
	173	* notify readers if they overlap with a writer.
	174	*
	175	* As the reservation object may be locked by multiple parties in an
	176	* undefined order, a #ww_acquire_ctx is passed to unwind if a cycle
	177	* is detected. See ww_mutex_lock() and ww_acquire_init(). A reservation
	178	* object may be locked by itself by passing NULL as @ctx.
	179	*/
	180	static inline int
	181	reservation_object_lock_interruptible(struct reservation_object *obj,
	182	struct ww_acquire_ctx *ctx)
	183	{
	184	return ww_mutex_lock_interruptible(&obj->lock, ctx);
	185	}
	186
	187
2955b73d CW	188	/**
	189	* reservation_object_trylock - trylock the reservation object
	190	* @obj: the reservation object
	191	*
	192	* Tries to lock the reservation object for exclusive access and modification.
	193	* Note, that the lock is only against other writers, readers will run
	194	* concurrently with a writer under RCU. The seqlock is used to notify readers
	195	* if they overlap with a writer.
	196	*
	197	* Also note that since no context is provided, no deadlock protection is
	198	* possible.
	199	*
	200	* Returns true if the lock was acquired, false otherwise.
	201	*/
	202	static inline bool __must_check
	203	reservation_object_trylock(struct reservation_object *obj)
	204	{
	205	return ww_mutex_trylock(&obj->lock);
	206	}
	207
122020af CW	208	/**
	209	* reservation_object_unlock - unlock the reservation object
	210	* @obj: the reservation object
	211	*
	212	* Unlocks the reservation object following exclusive access.
	213	*/
	214	static inline void
	215	reservation_object_unlock(struct reservation_object *obj)
	216	{
99fe21a7 CK	217	#ifdef CONFIG_DEBUG_MUTEXES
	218	/* Test shared fence slot reservation */
	219	if (obj->fence)
	220	obj->fence->shared_max = obj->fence->shared_count;
	221	#endif
122020af CW	222	ww_mutex_unlock(&obj->lock);
	223	}
	224
dad6c394 RC	225	/**
	226	* reservation_object_get_excl - get the reservation object's
	227	* exclusive fence, with update-side lock held
	228	* @obj: the reservation object
	229	*
	230	* Returns the exclusive fence (if any). Does NOT take a
372c9329 LS	231	* reference. Writers must hold obj->lock, readers may only
372c9329 LS	232	* hold a RCU read side lock.
dad6c394 RC	233	*
	234	* RETURNS
	235	* The exclusive fence or NULL
	236	*/
f54d1867	237	static inline struct dma_fence *
04a5faa8 ML	238	reservation_object_get_excl(struct reservation_object *obj)
04a5faa8 ML	239	{
3c3b177a ML	240	return rcu_dereference_protected(obj->fence_excl,
3c3b177a ML	241	reservation_object_held(obj));
04a5faa8 ML	242	}
04a5faa8 ML	243
dad6c394 RC	244	/**
	245	* reservation_object_get_excl_rcu - get the reservation object's
	246	* exclusive fence, without lock held.
	247	* @obj: the reservation object
	248	*
	249	* If there is an exclusive fence, this atomically increments it's
	250	* reference count and returns it.
	251	*
	252	* RETURNS
	253	* The exclusive fence or NULL if none
	254	*/
f54d1867	255	static inline struct dma_fence *
824815c4 RC	256	reservation_object_get_excl_rcu(struct reservation_object *obj)
824815c4 RC	257	{
f54d1867	258	struct dma_fence *fence;
6bfec6d9 CW	259
	260	if (!rcu_access_pointer(obj->fence_excl))
	261	return NULL;
	262
824815c4	263	rcu_read_lock();
6bfec6d9	264	fence = dma_fence_get_rcu_safe(&obj->fence_excl);
824815c4	265	rcu_read_unlock();
6bfec6d9	266
824815c4 RC	267	return fence;
	268	}
	269
ca05359f CK	270	int reservation_object_reserve_shared(struct reservation_object *obj,
ca05359f CK	271	unsigned int num_fences);
04a5faa8	272	void reservation_object_add_shared_fence(struct reservation_object *obj,
f54d1867	273	struct dma_fence *fence);
04a5faa8 ML	274
04a5faa8 ML	275	void reservation_object_add_excl_fence(struct reservation_object *obj,
f54d1867	276	struct dma_fence *fence);
04a5faa8	277
3c3b177a	278	int reservation_object_get_fences_rcu(struct reservation_object *obj,
f54d1867	279	struct dma_fence **pfence_excl,
3c3b177a	280	unsigned *pshared_count,
f54d1867	281	struct dma_fence ***pshared);
3c3b177a	282
7faf952a CK	283	int reservation_object_copy_fences(struct reservation_object *dst,
	284	struct reservation_object *src);
	285
3c3b177a ML	286	long reservation_object_wait_timeout_rcu(struct reservation_object *obj,
	287	bool wait_all, bool intr,
	288	unsigned long timeout);
	289
	290	bool reservation_object_test_signaled_rcu(struct reservation_object *obj,
	291	bool test_all);
	292
786d7257	293	#endif /* _LINUX_RESERVATION_H */