[mirror_ubuntu-bionic-kernel.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
 * @staged: staged copy of shared fences for RCU updates
 */
struct reservation_object {
	struct ww_mutex lock;
	seqcount_t seq;

	struct dma_fence __rcu *fence_excl;
	struct reservation_object_list __rcu *fence;
	struct reservation_object_list *staged;
};

#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);
	obj->staged = 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);
	}
	kfree(obj->staged);

	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_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)
{
	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);
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);

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
	71	* @staged: staged copy of shared fences for RCU updates
	72	*/
786d7257 ML	73	struct reservation_object {
786d7257 ML	74	struct ww_mutex lock;
3c3b177a	75	seqcount_t seq;
0ba6b8fb	76
f54d1867	77	struct dma_fence __rcu *fence_excl;
3c3b177a	78	struct reservation_object_list __rcu *fence;
04a5faa8	79	struct reservation_object_list *staged;
786d7257 ML	80	};
786d7257 ML	81
3c3b177a	82	#define reservation_object_held(obj) lockdep_is_held(&(obj)->lock.base)
04a5faa8 ML	83	#define reservation_object_assert_held(obj) \
	84	lockdep_assert_held(&(obj)->lock.base)
	85
dad6c394 RC	86	/**
	87	* reservation_object_init - initialize a reservation object
	88	* @obj: the reservation object
	89	*/
786d7257 ML	90	static inline void
	91	reservation_object_init(struct reservation_object *obj)
	92	{
	93	ww_mutex_init(&obj->lock, &reservation_ww_class);
0ba6b8fb	94
3c3b177a ML	95	__seqcount_init(&obj->seq, reservation_seqcount_string, &reservation_seqcount_class);
	96	RCU_INIT_POINTER(obj->fence, NULL);
	97	RCU_INIT_POINTER(obj->fence_excl, NULL);
04a5faa8	98	obj->staged = NULL;
786d7257 ML	99	}
786d7257 ML	100
dad6c394 RC	101	/**
	102	* reservation_object_fini - destroys a reservation object
	103	* @obj: the reservation object
	104	*/
786d7257 ML	105	static inline void
	106	reservation_object_fini(struct reservation_object *obj)
	107	{
0ba6b8fb	108	int i;
04a5faa8	109	struct reservation_object_list *fobj;
f54d1867	110	struct dma_fence *excl;
0ba6b8fb	111
04a5faa8 ML	112	/*
04a5faa8 ML	113	* This object should be dead and all references must have
3c3b177a	114	* been released to it, so no need to be protected with rcu.
04a5faa8	115	*/
3c3b177a ML	116	excl = rcu_dereference_protected(obj->fence_excl, 1);
3c3b177a ML	117	if (excl)
f54d1867	118	dma_fence_put(excl);
04a5faa8	119
3c3b177a	120	fobj = rcu_dereference_protected(obj->fence, 1);
04a5faa8 ML	121	if (fobj) {
04a5faa8 ML	122	for (i = 0; i < fobj->shared_count; ++i)
f54d1867	123	dma_fence_put(rcu_dereference_protected(fobj->shared[i], 1));
04a5faa8 ML	124
	125	kfree(fobj);
	126	}
	127	kfree(obj->staged);
0ba6b8fb	128
786d7257 ML	129	ww_mutex_destroy(&obj->lock);
	130	}
	131
dad6c394 RC	132	/**
	133	* reservation_object_get_list - get the reservation object's
	134	* shared fence list, with update-side lock held
	135	* @obj: the reservation object
	136	*
	137	* Returns the shared fence list. Does NOT take references to
	138	* the fence. The obj->lock must be held.
	139	*/
04a5faa8 ML	140	static inline struct reservation_object_list *
	141	reservation_object_get_list(struct reservation_object *obj)
	142	{
3c3b177a ML	143	return rcu_dereference_protected(obj->fence,
3c3b177a ML	144	reservation_object_held(obj));
04a5faa8 ML	145	}
04a5faa8 ML	146
122020af CW	147	/**
	148	* reservation_object_lock - lock the reservation object
	149	* @obj: the reservation object
	150	* @ctx: the locking context
	151	*
	152	* Locks the reservation object for exclusive access and modification. Note,
	153	* that the lock is only against other writers, readers will run concurrently
	154	* with a writer under RCU. The seqlock is used to notify readers if they
	155	* overlap with a writer.
	156	*
	157	* As the reservation object may be locked by multiple parties in an
	158	* undefined order, a #ww_acquire_ctx is passed to unwind if a cycle
	159	* is detected. See ww_mutex_lock() and ww_acquire_init(). A reservation
	160	* object may be locked by itself by passing NULL as @ctx.
	161	*/
	162	static inline int
	163	reservation_object_lock(struct reservation_object *obj,
	164	struct ww_acquire_ctx *ctx)
	165	{
	166	return ww_mutex_lock(&obj->lock, ctx);
	167	}
	168
	169	/**
	170	* reservation_object_unlock - unlock the reservation object
	171	* @obj: the reservation object
	172	*
	173	* Unlocks the reservation object following exclusive access.
	174	*/
	175	static inline void
	176	reservation_object_unlock(struct reservation_object *obj)
	177	{
	178	ww_mutex_unlock(&obj->lock);
	179	}
	180
dad6c394 RC	181	/**
	182	* reservation_object_get_excl - get the reservation object's
	183	* exclusive fence, with update-side lock held
	184	* @obj: the reservation object
	185	*
	186	* Returns the exclusive fence (if any). Does NOT take a
	187	* reference. The obj->lock must be held.
	188	*
	189	* RETURNS
	190	* The exclusive fence or NULL
	191	*/
f54d1867	192	static inline struct dma_fence *
04a5faa8 ML	193	reservation_object_get_excl(struct reservation_object *obj)
04a5faa8 ML	194	{
3c3b177a ML	195	return rcu_dereference_protected(obj->fence_excl,
3c3b177a ML	196	reservation_object_held(obj));
04a5faa8 ML	197	}
04a5faa8 ML	198
dad6c394 RC	199	/**
	200	* reservation_object_get_excl_rcu - get the reservation object's
	201	* exclusive fence, without lock held.
	202	* @obj: the reservation object
	203	*
	204	* If there is an exclusive fence, this atomically increments it's
	205	* reference count and returns it.
	206	*
	207	* RETURNS
	208	* The exclusive fence or NULL if none
	209	*/
f54d1867	210	static inline struct dma_fence *
824815c4 RC	211	reservation_object_get_excl_rcu(struct reservation_object *obj)
824815c4 RC	212	{
f54d1867	213	struct dma_fence *fence;
6bfec6d9 CW	214
	215	if (!rcu_access_pointer(obj->fence_excl))
	216	return NULL;
	217
824815c4	218	rcu_read_lock();
6bfec6d9	219	fence = dma_fence_get_rcu_safe(&obj->fence_excl);
824815c4	220	rcu_read_unlock();
6bfec6d9	221
824815c4 RC	222	return fence;
	223	}
	224
04a5faa8 ML	225	int reservation_object_reserve_shared(struct reservation_object *obj);
04a5faa8 ML	226	void reservation_object_add_shared_fence(struct reservation_object *obj,
f54d1867	227	struct dma_fence *fence);
04a5faa8 ML	228
04a5faa8 ML	229	void reservation_object_add_excl_fence(struct reservation_object *obj,
f54d1867	230	struct dma_fence *fence);
04a5faa8	231
3c3b177a	232	int reservation_object_get_fences_rcu(struct reservation_object *obj,
f54d1867	233	struct dma_fence **pfence_excl,
3c3b177a	234	unsigned *pshared_count,
f54d1867	235	struct dma_fence ***pshared);
3c3b177a ML	236
	237	long reservation_object_wait_timeout_rcu(struct reservation_object *obj,
	238	bool wait_all, bool intr,
	239	unsigned long timeout);
	240
	241	bool reservation_object_test_signaled_rcu(struct reservation_object *obj,
	242	bool test_all);
	243
786d7257	244	#endif /* _LINUX_RESERVATION_H */