[mirror_ubuntu-bionic-kernel.git] / drivers / dma-buf / reservation.c

/*
 * Copyright (C) 2012-2014 Canonical Ltd (Maarten Lankhorst)
 *
 * 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.
 *
 **************************************************************************/
/*
 * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
 */

#include <linux/reservation.h>
#include <linux/export.h>

/**
 * DOC: Reservation Object Overview
 *
 * The reservation object provides a mechanism to manage shared and
 * exclusive fences associated with a buffer.  A reservation object
 * can have attached one exclusive fence (normally associated with
 * write operations) or N shared fences (read operations).  The RCU
 * mechanism is used to protect read access to fences from locked
 * write-side updates.
 */

DEFINE_WW_CLASS(reservation_ww_class);
EXPORT_SYMBOL(reservation_ww_class);

struct lock_class_key reservation_seqcount_class;
EXPORT_SYMBOL(reservation_seqcount_class);

const char reservation_seqcount_string[] = "reservation_seqcount";
EXPORT_SYMBOL(reservation_seqcount_string);

/**
 * reservation_object_reserve_shared - Reserve space to add a shared
 * fence to a reservation_object.
 * @obj: reservation object
 *
 * Should be called before reservation_object_add_shared_fence().  Must
 * be called with obj->lock held.
 *
 * RETURNS
 * Zero for success, or -errno
 */
int reservation_object_reserve_shared(struct reservation_object *obj)
{
	struct reservation_object_list *fobj, *old;
	u32 max;

	old = reservation_object_get_list(obj);

	if (old && old->shared_max) {
		if (old->shared_count < old->shared_max) {
			/* perform an in-place update */
			kfree(obj->staged);
			obj->staged = NULL;
			return 0;
		} else
			max = old->shared_max * 2;
	} else
		max = 4;

	/*
	 * resize obj->staged or allocate if it doesn't exist,
	 * noop if already correct size
	 */
	fobj = krealloc(obj->staged, offsetof(typeof(*fobj), shared[max]),
			GFP_KERNEL);
	if (!fobj)
		return -ENOMEM;

	obj->staged = fobj;
	fobj->shared_max = max;
	return 0;
}
EXPORT_SYMBOL(reservation_object_reserve_shared);

static void
reservation_object_add_shared_inplace(struct reservation_object *obj,
				      struct reservation_object_list *fobj,
				      struct dma_fence *fence)
{
	u32 i;

	dma_fence_get(fence);

	preempt_disable();
	write_seqcount_begin(&obj->seq);

	for (i = 0; i < fobj->shared_count; ++i) {
		struct dma_fence *old_fence;

		old_fence = rcu_dereference_protected(fobj->shared[i],
						reservation_object_held(obj));

		if (old_fence->context == fence->context) {
			/* memory barrier is added by write_seqcount_begin */
			RCU_INIT_POINTER(fobj->shared[i], fence);
			write_seqcount_end(&obj->seq);
			preempt_enable();

			dma_fence_put(old_fence);
			return;
		}
	}

	/*
	 * memory barrier is added by write_seqcount_begin,
	 * fobj->shared_count is protected by this lock too
	 */
	RCU_INIT_POINTER(fobj->shared[fobj->shared_count], fence);
	fobj->shared_count++;

	write_seqcount_end(&obj->seq);
	preempt_enable();
}

static void
reservation_object_add_shared_replace(struct reservation_object *obj,
				      struct reservation_object_list *old,
				      struct reservation_object_list *fobj,
				      struct dma_fence *fence)
{
	unsigned i;
	struct dma_fence *old_fence = NULL;

	dma_fence_get(fence);

	if (!old) {
		RCU_INIT_POINTER(fobj->shared[0], fence);
		fobj->shared_count = 1;
		goto done;
	}

	/*
	 * no need to bump fence refcounts, rcu_read access
	 * requires the use of kref_get_unless_zero, and the
	 * references from the old struct are carried over to
	 * the new.
	 */
	fobj->shared_count = old->shared_count;

	for (i = 0; i < old->shared_count; ++i) {
		struct dma_fence *check;

		check = rcu_dereference_protected(old->shared[i],
						reservation_object_held(obj));

		if (!old_fence && check->context == fence->context) {
			old_fence = check;
			RCU_INIT_POINTER(fobj->shared[i], fence);
		} else
			RCU_INIT_POINTER(fobj->shared[i], check);
	}
	if (!old_fence) {
		RCU_INIT_POINTER(fobj->shared[fobj->shared_count], fence);
		fobj->shared_count++;
	}

done:
	preempt_disable();
	write_seqcount_begin(&obj->seq);
	/*
	 * RCU_INIT_POINTER can be used here,
	 * seqcount provides the necessary barriers
	 */
	RCU_INIT_POINTER(obj->fence, fobj);
	write_seqcount_end(&obj->seq);
	preempt_enable();

	if (old)
		kfree_rcu(old, rcu);

	dma_fence_put(old_fence);
}

/**
 * reservation_object_add_shared_fence - Add a fence to a shared slot
 * @obj: the reservation object
 * @fence: the shared fence to add
 *
 * Add a fence to a shared slot, obj->lock must be held, and
 * reservation_object_reserve_shared() has been called.
 */
void reservation_object_add_shared_fence(struct reservation_object *obj,
					 struct dma_fence *fence)
{
	struct reservation_object_list *old, *fobj = obj->staged;

	old = reservation_object_get_list(obj);
	obj->staged = NULL;

	if (!fobj) {
		BUG_ON(old->shared_count >= old->shared_max);
		reservation_object_add_shared_inplace(obj, old, fence);
	} else
		reservation_object_add_shared_replace(obj, old, fobj, fence);
}
EXPORT_SYMBOL(reservation_object_add_shared_fence);

/**
 * reservation_object_add_excl_fence - Add an exclusive fence.
 * @obj: the reservation object
 * @fence: the shared fence to add
 *
 * Add a fence to the exclusive slot.  The obj->lock must be held.
 */
void reservation_object_add_excl_fence(struct reservation_object *obj,
				       struct dma_fence *fence)
{
	struct dma_fence *old_fence = reservation_object_get_excl(obj);
	struct reservation_object_list *old;
	u32 i = 0;

	old = reservation_object_get_list(obj);
	if (old)
		i = old->shared_count;

	if (fence)
		dma_fence_get(fence);

	preempt_disable();
	write_seqcount_begin(&obj->seq);
	/* write_seqcount_begin provides the necessary memory barrier */
	RCU_INIT_POINTER(obj->fence_excl, fence);
	if (old)
		old->shared_count = 0;
	write_seqcount_end(&obj->seq);
	preempt_enable();

	/* inplace update, no shared fences */
	while (i--)
		dma_fence_put(rcu_dereference_protected(old->shared[i],
						reservation_object_held(obj)));

	dma_fence_put(old_fence);
}
EXPORT_SYMBOL(reservation_object_add_excl_fence);

/**
 * reservation_object_get_fences_rcu - Get an object's shared and exclusive
 * fences without update side lock held
 * @obj: the reservation object
 * @pfence_excl: the returned exclusive fence (or NULL)
 * @pshared_count: the number of shared fences returned
 * @pshared: the array of shared fence ptrs returned (array is krealloc'd to
 * the required size, and must be freed by caller)
 *
 * RETURNS
 * Zero or -errno
 */
int reservation_object_get_fences_rcu(struct reservation_object *obj,
				      struct dma_fence **pfence_excl,
				      unsigned *pshared_count,
				      struct dma_fence ***pshared)
{
	struct dma_fence **shared = NULL;
	struct dma_fence *fence_excl;
	unsigned int shared_count;
	int ret = 1;

	do {
		struct reservation_object_list *fobj;
		unsigned seq;
		unsigned int i;

		shared_count = i = 0;

		rcu_read_lock();
		seq = read_seqcount_begin(&obj->seq);

		fence_excl = rcu_dereference(obj->fence_excl);
		if (fence_excl && !dma_fence_get_rcu(fence_excl))
			goto unlock;

		fobj = rcu_dereference(obj->fence);
		if (fobj) {
			struct dma_fence **nshared;
			size_t sz = sizeof(*shared) * fobj->shared_max;

			nshared = krealloc(shared, sz,
					   GFP_NOWAIT | __GFP_NOWARN);
			if (!nshared) {
				rcu_read_unlock();
				nshared = krealloc(shared, sz, GFP_KERNEL);
				if (nshared) {
					shared = nshared;
					continue;
				}

				ret = -ENOMEM;
				break;
			}
			shared = nshared;
			shared_count = fobj->shared_count;

			for (i = 0; i < shared_count; ++i) {
				shared[i] = rcu_dereference(fobj->shared[i]);
				if (!dma_fence_get_rcu(shared[i]))
					break;
			}
		}

		if (i != shared_count || read_seqcount_retry(&obj->seq, seq)) {
			while (i--)
				dma_fence_put(shared[i]);
			dma_fence_put(fence_excl);
			goto unlock;
		}

		ret = 0;
unlock:
		rcu_read_unlock();
	} while (ret);

	if (!shared_count) {
		kfree(shared);
		shared = NULL;
	}

	*pshared_count = shared_count;
	*pshared = shared;
	*pfence_excl = fence_excl;

	return ret;
}
EXPORT_SYMBOL_GPL(reservation_object_get_fences_rcu);

/**
 * reservation_object_wait_timeout_rcu - Wait on reservation's objects
 * shared and/or exclusive fences.
 * @obj: the reservation object
 * @wait_all: if true, wait on all fences, else wait on just exclusive fence
 * @intr: if true, do interruptible wait
 * @timeout: timeout value in jiffies or zero to return immediately
 *
 * RETURNS
 * Returns -ERESTARTSYS if interrupted, 0 if the wait timed out, or
 * greater than zer on success.
 */
long reservation_object_wait_timeout_rcu(struct reservation_object *obj,
					 bool wait_all, bool intr,
					 unsigned long timeout)
{
	struct dma_fence *fence;
	unsigned seq, shared_count, i = 0;
	long ret = timeout ? timeout : 1;

retry:
	fence = NULL;
	shared_count = 0;
	seq = read_seqcount_begin(&obj->seq);
	rcu_read_lock();

	if (wait_all) {
		struct reservation_object_list *fobj =
						rcu_dereference(obj->fence);

		if (fobj)
			shared_count = fobj->shared_count;

		for (i = 0; i < shared_count; ++i) {
			struct dma_fence *lfence = rcu_dereference(fobj->shared[i]);

			if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT,
				     &lfence->flags))
				continue;

			if (!dma_fence_get_rcu(lfence))
				goto unlock_retry;

			if (dma_fence_is_signaled(lfence)) {
				dma_fence_put(lfence);
				continue;
			}

			fence = lfence;
			break;
		}
	}

	if (!shared_count) {
		struct dma_fence *fence_excl = rcu_dereference(obj->fence_excl);

		if (fence_excl &&
		    !test_bit(DMA_FENCE_FLAG_SIGNALED_BIT,
			      &fence_excl->flags)) {
			if (!dma_fence_get_rcu(fence_excl))
				goto unlock_retry;

			if (dma_fence_is_signaled(fence_excl))
				dma_fence_put(fence_excl);
			else
				fence = fence_excl;
		}
	}

	rcu_read_unlock();
	if (fence) {
		if (read_seqcount_retry(&obj->seq, seq)) {
			dma_fence_put(fence);
			goto retry;
		}

		ret = dma_fence_wait_timeout(fence, intr, ret);
		dma_fence_put(fence);
		if (ret > 0 && wait_all && (i + 1 < shared_count))
			goto retry;
	}
	return ret;

unlock_retry:
	rcu_read_unlock();
	goto retry;
}
EXPORT_SYMBOL_GPL(reservation_object_wait_timeout_rcu);


static inline int
reservation_object_test_signaled_single(struct dma_fence *passed_fence)
{
	struct dma_fence *fence, *lfence = passed_fence;
	int ret = 1;

	if (!test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &lfence->flags)) {
		fence = dma_fence_get_rcu(lfence);
		if (!fence)
			return -1;

		ret = !!dma_fence_is_signaled(fence);
		dma_fence_put(fence);
	}
	return ret;
}

/**
 * reservation_object_test_signaled_rcu - Test if a reservation object's
 * fences have been signaled.
 * @obj: the reservation object
 * @test_all: if true, test all fences, otherwise only test the exclusive
 * fence
 *
 * RETURNS
 * true if all fences signaled, else false
 */
bool reservation_object_test_signaled_rcu(struct reservation_object *obj,
					  bool test_all)
{
	unsigned seq, shared_count;
	int ret;

	rcu_read_lock();
retry:
	ret = true;
	shared_count = 0;
	seq = read_seqcount_begin(&obj->seq);

	if (test_all) {
		unsigned i;

		struct reservation_object_list *fobj =
						rcu_dereference(obj->fence);

		if (fobj)
			shared_count = fobj->shared_count;

		for (i = 0; i < shared_count; ++i) {
			struct dma_fence *fence = rcu_dereference(fobj->shared[i]);

			ret = reservation_object_test_signaled_single(fence);
			if (ret < 0)
				goto retry;
			else if (!ret)
				break;
		}

		if (read_seqcount_retry(&obj->seq, seq))
			goto retry;
	}

	if (!shared_count) {
		struct dma_fence *fence_excl = rcu_dereference(obj->fence_excl);

		if (fence_excl) {
			ret = reservation_object_test_signaled_single(
								fence_excl);
			if (ret < 0)
				goto retry;

			if (read_seqcount_retry(&obj->seq, seq))
				goto retry;
		}
	}

	rcu_read_unlock();
	return ret;
}
EXPORT_SYMBOL_GPL(reservation_object_test_signaled_rcu);
Commit	Line	Data
786d7257	1	/*
04a5faa8	2	* Copyright (C) 2012-2014 Canonical Ltd (Maarten Lankhorst)
786d7257 ML	3	*
	4	* Based on bo.c which bears the following copyright notice,
	5	* but is dual licensed:
	6	*
	7	* Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
	8	* All Rights Reserved.
	9	*
	10	* Permission is hereby granted, free of charge, to any person obtaining a
	11	* copy of this software and associated documentation files (the
	12	* "Software"), to deal in the Software without restriction, including
	13	* without limitation the rights to use, copy, modify, merge, publish,
	14	* distribute, sub license, and/or sell copies of the Software, and to
	15	* permit persons to whom the Software is furnished to do so, subject to
	16	* the following conditions:
	17	*
	18	* The above copyright notice and this permission notice (including the
	19	* next paragraph) shall be included in all copies or substantial portions
	20	* of the Software.
	21	*
	22	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	23	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	24	* FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
	25	* THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
	26	* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
	27	* OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
	28	* USE OR OTHER DEALINGS IN THE SOFTWARE.
	29	*
	30	**************************************************************************/
	31	/*
	32	* Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
	33	*/
	34
	35	#include <linux/reservation.h>
	36	#include <linux/export.h>
	37
dad6c394 RC	38	/**
	39	* DOC: Reservation Object Overview
	40	*
	41	* The reservation object provides a mechanism to manage shared and
	42	* exclusive fences associated with a buffer. A reservation object
	43	* can have attached one exclusive fence (normally associated with
	44	* write operations) or N shared fences (read operations). The RCU
	45	* mechanism is used to protect read access to fences from locked
	46	* write-side updates.
	47	*/
	48
786d7257 ML	49	DEFINE_WW_CLASS(reservation_ww_class);
786d7257 ML	50	EXPORT_SYMBOL(reservation_ww_class);
04a5faa8	51
3c3b177a ML	52	struct lock_class_key reservation_seqcount_class;
	53	EXPORT_SYMBOL(reservation_seqcount_class);
	54
	55	const char reservation_seqcount_string[] = "reservation_seqcount";
	56	EXPORT_SYMBOL(reservation_seqcount_string);
dad6c394 RC	57
	58	/**
	59	* reservation_object_reserve_shared - Reserve space to add a shared
	60	* fence to a reservation_object.
	61	* @obj: reservation object
	62	*
	63	* Should be called before reservation_object_add_shared_fence(). Must
	64	* be called with obj->lock held.
	65	*
	66	* RETURNS
	67	* Zero for success, or -errno
04a5faa8 ML	68	*/
	69	int reservation_object_reserve_shared(struct reservation_object *obj)
	70	{
	71	struct reservation_object_list fobj, old;
	72	u32 max;
	73
	74	old = reservation_object_get_list(obj);
	75
	76	if (old && old->shared_max) {
	77	if (old->shared_count < old->shared_max) {
	78	/* perform an in-place update */
	79	kfree(obj->staged);
	80	obj->staged = NULL;
	81	return 0;
	82	} else
	83	max = old->shared_max * 2;
	84	} else
	85	max = 4;
	86
	87	/*
	88	* resize obj->staged or allocate if it doesn't exist,
	89	* noop if already correct size
	90	*/
	91	fobj = krealloc(obj->staged, offsetof(typeof(*fobj), shared[max]),
	92	GFP_KERNEL);
	93	if (!fobj)
	94	return -ENOMEM;
	95
	96	obj->staged = fobj;
	97	fobj->shared_max = max;
	98	return 0;
	99	}
	100	EXPORT_SYMBOL(reservation_object_reserve_shared);
	101
	102	static void
	103	reservation_object_add_shared_inplace(struct reservation_object *obj,
	104	struct reservation_object_list *fobj,
f54d1867	105	struct dma_fence *fence)
04a5faa8 ML	106	{
	107	u32 i;
	108
f54d1867	109	dma_fence_get(fence);
3c3b177a ML	110
	111	preempt_disable();
	112	write_seqcount_begin(&obj->seq);
	113
04a5faa8	114	for (i = 0; i < fobj->shared_count; ++i) {
f54d1867	115	struct dma_fence *old_fence;
04a5faa8	116
3c3b177a ML	117	old_fence = rcu_dereference_protected(fobj->shared[i],
3c3b177a ML	118	reservation_object_held(obj));
04a5faa8	119
3c3b177a ML	120	if (old_fence->context == fence->context) {
	121	/* memory barrier is added by write_seqcount_begin */
	122	RCU_INIT_POINTER(fobj->shared[i], fence);
	123	write_seqcount_end(&obj->seq);
	124	preempt_enable();
04a5faa8	125
f54d1867	126	dma_fence_put(old_fence);
04a5faa8 ML	127	return;
	128	}
	129	}
	130
04a5faa8	131	/*
3c3b177a ML	132	* memory barrier is added by write_seqcount_begin,
3c3b177a ML	133	* fobj->shared_count is protected by this lock too
04a5faa8	134	*/
3c3b177a	135	RCU_INIT_POINTER(fobj->shared[fobj->shared_count], fence);
04a5faa8	136	fobj->shared_count++;
3c3b177a ML	137
	138	write_seqcount_end(&obj->seq);
	139	preempt_enable();
04a5faa8 ML	140	}
	141
	142	static void
	143	reservation_object_add_shared_replace(struct reservation_object *obj,
	144	struct reservation_object_list *old,
	145	struct reservation_object_list *fobj,
f54d1867	146	struct dma_fence *fence)
04a5faa8 ML	147	{
04a5faa8 ML	148	unsigned i;
f54d1867	149	struct dma_fence *old_fence = NULL;
04a5faa8	150
f54d1867	151	dma_fence_get(fence);
04a5faa8 ML	152
04a5faa8 ML	153	if (!old) {
3c3b177a	154	RCU_INIT_POINTER(fobj->shared[0], fence);
04a5faa8 ML	155	fobj->shared_count = 1;
	156	goto done;
	157	}
	158
	159	/*
	160	* no need to bump fence refcounts, rcu_read access
	161	* requires the use of kref_get_unless_zero, and the
	162	* references from the old struct are carried over to
	163	* the new.
	164	*/
	165	fobj->shared_count = old->shared_count;
	166
	167	for (i = 0; i < old->shared_count; ++i) {
f54d1867	168	struct dma_fence *check;
3c3b177a ML	169
	170	check = rcu_dereference_protected(old->shared[i],
	171	reservation_object_held(obj));
	172
	173	if (!old_fence && check->context == fence->context) {
	174	old_fence = check;
	175	RCU_INIT_POINTER(fobj->shared[i], fence);
04a5faa8	176	} else
3c3b177a ML	177	RCU_INIT_POINTER(fobj->shared[i], check);
	178	}
	179	if (!old_fence) {
	180	RCU_INIT_POINTER(fobj->shared[fobj->shared_count], fence);
	181	fobj->shared_count++;
04a5faa8	182	}
04a5faa8 ML	183
04a5faa8 ML	184	done:
3c3b177a ML	185	preempt_disable();
	186	write_seqcount_begin(&obj->seq);
	187	/*
	188	* RCU_INIT_POINTER can be used here,
	189	* seqcount provides the necessary barriers
	190	*/
	191	RCU_INIT_POINTER(obj->fence, fobj);
	192	write_seqcount_end(&obj->seq);
	193	preempt_enable();
	194
	195	if (old)
	196	kfree_rcu(old, rcu);
	197
f3e31b73	198	dma_fence_put(old_fence);
04a5faa8 ML	199	}
04a5faa8 ML	200
dad6c394 RC	201	/**
	202	* reservation_object_add_shared_fence - Add a fence to a shared slot
	203	* @obj: the reservation object
	204	* @fence: the shared fence to add
	205	*
04a5faa8	206	* Add a fence to a shared slot, obj->lock must be held, and
f5bef0b8	207	* reservation_object_reserve_shared() has been called.
04a5faa8 ML	208	*/
04a5faa8 ML	209	void reservation_object_add_shared_fence(struct reservation_object *obj,
f54d1867	210	struct dma_fence *fence)
04a5faa8 ML	211	{
	212	struct reservation_object_list old, fobj = obj->staged;
	213
	214	old = reservation_object_get_list(obj);
	215	obj->staged = NULL;
	216
	217	if (!fobj) {
3c3b177a	218	BUG_ON(old->shared_count >= old->shared_max);
04a5faa8 ML	219	reservation_object_add_shared_inplace(obj, old, fence);
	220	} else
	221	reservation_object_add_shared_replace(obj, old, fobj, fence);
	222	}
	223	EXPORT_SYMBOL(reservation_object_add_shared_fence);
	224
dad6c394 RC	225	/**
	226	* reservation_object_add_excl_fence - Add an exclusive fence.
	227	* @obj: the reservation object
	228	* @fence: the shared fence to add
	229	*
	230	* Add a fence to the exclusive slot. The obj->lock must be held.
	231	*/
04a5faa8	232	void reservation_object_add_excl_fence(struct reservation_object *obj,
f54d1867	233	struct dma_fence *fence)
04a5faa8	234	{
f54d1867	235	struct dma_fence *old_fence = reservation_object_get_excl(obj);
04a5faa8 ML	236	struct reservation_object_list *old;
	237	u32 i = 0;
	238
	239	old = reservation_object_get_list(obj);
3c3b177a	240	if (old)
04a5faa8	241	i = old->shared_count;
04a5faa8 ML	242
04a5faa8 ML	243	if (fence)
f54d1867	244	dma_fence_get(fence);
04a5faa8	245
3c3b177a ML	246	preempt_disable();
	247	write_seqcount_begin(&obj->seq);
	248	/* write_seqcount_begin provides the necessary memory barrier */
	249	RCU_INIT_POINTER(obj->fence_excl, fence);
	250	if (old)
	251	old->shared_count = 0;
	252	write_seqcount_end(&obj->seq);
	253	preempt_enable();
04a5faa8 ML	254
	255	/* inplace update, no shared fences */
	256	while (i--)
f54d1867	257	dma_fence_put(rcu_dereference_protected(old->shared[i],
3c3b177a	258	reservation_object_held(obj)));
04a5faa8	259
f3e31b73	260	dma_fence_put(old_fence);
04a5faa8 ML	261	}
04a5faa8 ML	262	EXPORT_SYMBOL(reservation_object_add_excl_fence);
3c3b177a	263
dad6c394 RC	264	/**
	265	* reservation_object_get_fences_rcu - Get an object's shared and exclusive
	266	* fences without update side lock held
	267	* @obj: the reservation object
	268	* @pfence_excl: the returned exclusive fence (or NULL)
	269	* @pshared_count: the number of shared fences returned
	270	* @pshared: the array of shared fence ptrs returned (array is krealloc'd to
	271	* the required size, and must be freed by caller)
	272	*
	273	* RETURNS
	274	* Zero or -errno
	275	*/
3c3b177a	276	int reservation_object_get_fences_rcu(struct reservation_object *obj,
f54d1867	277	struct dma_fence **pfence_excl,
3c3b177a	278	unsigned *pshared_count,
f54d1867	279	struct dma_fence ***pshared)
3c3b177a	280	{
f54d1867 CW	281	struct dma_fence **shared = NULL;
f54d1867 CW	282	struct dma_fence *fence_excl;
fedf5413 CW	283	unsigned int shared_count;
fedf5413 CW	284	int ret = 1;
3c3b177a	285
fedf5413	286	do {
3c3b177a ML	287	struct reservation_object_list *fobj;
3c3b177a ML	288	unsigned seq;
fedf5413	289	unsigned int i;
3c3b177a	290
fedf5413	291	shared_count = i = 0;
3c3b177a ML	292
3c3b177a ML	293	rcu_read_lock();
fedf5413 CW	294	seq = read_seqcount_begin(&obj->seq);
	295
	296	fence_excl = rcu_dereference(obj->fence_excl);
f54d1867	297	if (fence_excl && !dma_fence_get_rcu(fence_excl))
fedf5413	298	goto unlock;
3c3b177a ML	299
	300	fobj = rcu_dereference(obj->fence);
	301	if (fobj) {
f54d1867	302	struct dma_fence **nshared;
3c3b177a ML	303	size_t sz = sizeof(shared) fobj->shared_max;
	304
	305	nshared = krealloc(shared, sz,
	306	GFP_NOWAIT \| __GFP_NOWARN);
	307	if (!nshared) {
	308	rcu_read_unlock();
	309	nshared = krealloc(shared, sz, GFP_KERNEL);
	310	if (nshared) {
	311	shared = nshared;
	312	continue;
	313	}
	314
	315	ret = -ENOMEM;
3c3b177a ML	316	break;
	317	}
	318	shared = nshared;
3c3b177a	319	shared_count = fobj->shared_count;
3c3b177a ML	320
3c3b177a ML	321	for (i = 0; i < shared_count; ++i) {
fedf5413	322	shared[i] = rcu_dereference(fobj->shared[i]);
f54d1867	323	if (!dma_fence_get_rcu(shared[i]))
fedf5413	324	break;
3c3b177a	325	}
fedf5413	326	}
3c3b177a	327
fedf5413 CW	328	if (i != shared_count \|\| read_seqcount_retry(&obj->seq, seq)) {
fedf5413 CW	329	while (i--)
f54d1867 CW	330	dma_fence_put(shared[i]);
f54d1867 CW	331	dma_fence_put(fence_excl);
fedf5413 CW	332	goto unlock;
	333	}
	334
	335	ret = 0;
3c3b177a ML	336	unlock:
3c3b177a ML	337	rcu_read_unlock();
fedf5413 CW	338	} while (ret);
	339
	340	if (!shared_count) {
3c3b177a	341	kfree(shared);
fedf5413	342	shared = NULL;
3c3b177a	343	}
fedf5413 CW	344
	345	*pshared_count = shared_count;
	346	*pshared = shared;
3c3b177a ML	347	*pfence_excl = fence_excl;
	348
	349	return ret;
	350	}
	351	EXPORT_SYMBOL_GPL(reservation_object_get_fences_rcu);
	352
dad6c394 RC	353	/**
	354	* reservation_object_wait_timeout_rcu - Wait on reservation's objects
	355	* shared and/or exclusive fences.
	356	* @obj: the reservation object
	357	* @wait_all: if true, wait on all fences, else wait on just exclusive fence
	358	* @intr: if true, do interruptible wait
	359	* @timeout: timeout value in jiffies or zero to return immediately
	360	*
	361	* RETURNS
	362	* Returns -ERESTARTSYS if interrupted, 0 if the wait timed out, or
	363	* greater than zer on success.
	364	*/
3c3b177a ML	365	long reservation_object_wait_timeout_rcu(struct reservation_object *obj,
	366	bool wait_all, bool intr,
	367	unsigned long timeout)
	368	{
f54d1867	369	struct dma_fence *fence;
3c3b177a	370	unsigned seq, shared_count, i = 0;
06a66b5c	371	long ret = timeout ? timeout : 1;
fb8b7d2b	372
3c3b177a ML	373	retry:
	374	fence = NULL;
	375	shared_count = 0;
	376	seq = read_seqcount_begin(&obj->seq);
	377	rcu_read_lock();
	378
	379	if (wait_all) {
5136629d JT	380	struct reservation_object_list *fobj =
5136629d JT	381	rcu_dereference(obj->fence);
3c3b177a ML	382
	383	if (fobj)
	384	shared_count = fobj->shared_count;
	385
3c3b177a	386	for (i = 0; i < shared_count; ++i) {
f54d1867	387	struct dma_fence *lfence = rcu_dereference(fobj->shared[i]);
3c3b177a	388
f54d1867 CW	389	if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT,
f54d1867 CW	390	&lfence->flags))
3c3b177a ML	391	continue;
3c3b177a ML	392
f54d1867	393	if (!dma_fence_get_rcu(lfence))
3c3b177a ML	394	goto unlock_retry;
3c3b177a ML	395
f54d1867 CW	396	if (dma_fence_is_signaled(lfence)) {
f54d1867 CW	397	dma_fence_put(lfence);
3c3b177a ML	398	continue;
	399	}
	400
	401	fence = lfence;
	402	break;
	403	}
	404	}
	405
	406	if (!shared_count) {
f54d1867	407	struct dma_fence *fence_excl = rcu_dereference(obj->fence_excl);
3c3b177a	408
3c3b177a	409	if (fence_excl &&
f54d1867 CW	410	!test_bit(DMA_FENCE_FLAG_SIGNALED_BIT,
	411	&fence_excl->flags)) {
	412	if (!dma_fence_get_rcu(fence_excl))
3c3b177a ML	413	goto unlock_retry;
3c3b177a ML	414
f54d1867 CW	415	if (dma_fence_is_signaled(fence_excl))
f54d1867 CW	416	dma_fence_put(fence_excl);
3c3b177a ML	417	else
	418	fence = fence_excl;
	419	}
	420	}
	421
	422	rcu_read_unlock();
	423	if (fence) {
1cec20f0	424	if (read_seqcount_retry(&obj->seq, seq)) {
f54d1867	425	dma_fence_put(fence);
1cec20f0 CW	426	goto retry;
	427	}
	428
f54d1867 CW	429	ret = dma_fence_wait_timeout(fence, intr, ret);
f54d1867 CW	430	dma_fence_put(fence);
3c3b177a ML	431	if (ret > 0 && wait_all && (i + 1 < shared_count))
	432	goto retry;
	433	}
	434	return ret;
	435
	436	unlock_retry:
	437	rcu_read_unlock();
	438	goto retry;
	439	}
	440	EXPORT_SYMBOL_GPL(reservation_object_wait_timeout_rcu);
	441
	442
	443	static inline int
f54d1867	444	reservation_object_test_signaled_single(struct dma_fence *passed_fence)
3c3b177a	445	{
f54d1867	446	struct dma_fence fence, lfence = passed_fence;
3c3b177a ML	447	int ret = 1;
3c3b177a ML	448
f54d1867 CW	449	if (!test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &lfence->flags)) {
f54d1867 CW	450	fence = dma_fence_get_rcu(lfence);
3c3b177a ML	451	if (!fence)
	452	return -1;
	453
f54d1867 CW	454	ret = !!dma_fence_is_signaled(fence);
f54d1867 CW	455	dma_fence_put(fence);
3c3b177a ML	456	}
	457	return ret;
	458	}
	459
dad6c394 RC	460	/**
	461	* reservation_object_test_signaled_rcu - Test if a reservation object's
	462	* fences have been signaled.
	463	* @obj: the reservation object
	464	* @test_all: if true, test all fences, otherwise only test the exclusive
	465	* fence
	466	*
	467	* RETURNS
	468	* true if all fences signaled, else false
	469	*/
3c3b177a ML	470	bool reservation_object_test_signaled_rcu(struct reservation_object *obj,
	471	bool test_all)
	472	{
	473	unsigned seq, shared_count;
b68d8379	474	int ret;
3c3b177a	475
b68d8379	476	rcu_read_lock();
3c3b177a	477	retry:
b68d8379	478	ret = true;
3c3b177a ML	479	shared_count = 0;
3c3b177a ML	480	seq = read_seqcount_begin(&obj->seq);
3c3b177a ML	481
	482	if (test_all) {
	483	unsigned i;
	484
5136629d JT	485	struct reservation_object_list *fobj =
5136629d JT	486	rcu_dereference(obj->fence);
3c3b177a ML	487
	488	if (fobj)
	489	shared_count = fobj->shared_count;
	490
3c3b177a	491	for (i = 0; i < shared_count; ++i) {
f54d1867	492	struct dma_fence *fence = rcu_dereference(fobj->shared[i]);
3c3b177a ML	493
	494	ret = reservation_object_test_signaled_single(fence);
	495	if (ret < 0)
b68d8379	496	goto retry;
3c3b177a ML	497	else if (!ret)
	498	break;
	499	}
	500
b68d8379 CW	501	if (read_seqcount_retry(&obj->seq, seq))
b68d8379 CW	502	goto retry;
3c3b177a ML	503	}
	504
	505	if (!shared_count) {
f54d1867	506	struct dma_fence *fence_excl = rcu_dereference(obj->fence_excl);
3c3b177a	507
3c3b177a	508	if (fence_excl) {
5136629d JT	509	ret = reservation_object_test_signaled_single(
5136629d JT	510	fence_excl);
3c3b177a	511	if (ret < 0)
b68d8379 CW	512	goto retry;
	513
	514	if (read_seqcount_retry(&obj->seq, seq))
	515	goto retry;
3c3b177a ML	516	}
	517	}
	518
	519	rcu_read_unlock();
	520	return ret;
3c3b177a ML	521	}
3c3b177a ML	522	EXPORT_SYMBOL_GPL(reservation_object_test_signaled_rcu);