[linux.git] / drivers / iommu / iova.c

/*
 * Copyright © 2006-2009, Intel Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
 * Place - Suite 330, Boston, MA 02111-1307 USA.
 *
 * Author: Anil S Keshavamurthy <[email protected]>
 */

#include <linux/iova.h>

void
init_iova_domain(struct iova_domain *iovad, unsigned long pfn_32bit)
{
	spin_lock_init(&iovad->iova_rbtree_lock);
	iovad->rbroot = RB_ROOT;
	iovad->cached32_node = NULL;
	iovad->dma_32bit_pfn = pfn_32bit;
}

static struct rb_node *
__get_cached_rbnode(struct iova_domain *iovad, unsigned long *limit_pfn)
{
	if ((*limit_pfn != iovad->dma_32bit_pfn) ||
		(iovad->cached32_node == NULL))
		return rb_last(&iovad->rbroot);
	else {
		struct rb_node *prev_node = rb_prev(iovad->cached32_node);
		struct iova *curr_iova =
			container_of(iovad->cached32_node, struct iova, node);
		*limit_pfn = curr_iova->pfn_lo - 1;
		return prev_node;
	}
}

static void
__cached_rbnode_insert_update(struct iova_domain *iovad,
	unsigned long limit_pfn, struct iova *new)
{
	if (limit_pfn != iovad->dma_32bit_pfn)
		return;
	iovad->cached32_node = &new->node;
}

static void
__cached_rbnode_delete_update(struct iova_domain *iovad, struct iova *free)
{
	struct iova *cached_iova;
	struct rb_node *curr;

	if (!iovad->cached32_node)
		return;
	curr = iovad->cached32_node;
	cached_iova = container_of(curr, struct iova, node);

	if (free->pfn_lo >= cached_iova->pfn_lo) {
		struct rb_node *node = rb_next(&free->node);
		struct iova *iova = container_of(node, struct iova, node);

		/* only cache if it's below 32bit pfn */
		if (node && iova->pfn_lo < iovad->dma_32bit_pfn)
			iovad->cached32_node = node;
		else
			iovad->cached32_node = NULL;
	}
}

/* Computes the padding size required, to make the
 * the start address naturally aligned on its size
 */
static int
iova_get_pad_size(int size, unsigned int limit_pfn)
{
	unsigned int pad_size = 0;
	unsigned int order = ilog2(size);

	if (order)
		pad_size = (limit_pfn + 1) % (1 << order);

	return pad_size;
}

static int __alloc_and_insert_iova_range(struct iova_domain *iovad,
		unsigned long size, unsigned long limit_pfn,
			struct iova *new, bool size_aligned)
{
	struct rb_node *prev, *curr = NULL;
	unsigned long flags;
	unsigned long saved_pfn;
	unsigned int pad_size = 0;

	/* Walk the tree backwards */
	spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
	saved_pfn = limit_pfn;
	curr = __get_cached_rbnode(iovad, &limit_pfn);
	prev = curr;
	while (curr) {
		struct iova *curr_iova = container_of(curr, struct iova, node);

		if (limit_pfn < curr_iova->pfn_lo)
			goto move_left;
		else if (limit_pfn < curr_iova->pfn_hi)
			goto adjust_limit_pfn;
		else {
			if (size_aligned)
				pad_size = iova_get_pad_size(size, limit_pfn);
			if ((curr_iova->pfn_hi + size + pad_size) <= limit_pfn)
				break;	/* found a free slot */
		}
adjust_limit_pfn:
		limit_pfn = curr_iova->pfn_lo - 1;
move_left:
		prev = curr;
		curr = rb_prev(curr);
	}

	if (!curr) {
		if (size_aligned)
			pad_size = iova_get_pad_size(size, limit_pfn);
		if ((IOVA_START_PFN + size + pad_size) > limit_pfn) {
			spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
			return -ENOMEM;
		}
	}

	/* pfn_lo will point to size aligned address if size_aligned is set */
	new->pfn_lo = limit_pfn - (size + pad_size) + 1;
	new->pfn_hi = new->pfn_lo + size - 1;

	/* Insert the new_iova into domain rbtree by holding writer lock */
	/* Add new node and rebalance tree. */
	{
		struct rb_node **entry, *parent = NULL;

		/* If we have 'prev', it's a valid place to start the
		   insertion. Otherwise, start from the root. */
		if (prev)
			entry = &prev;
		else
			entry = &iovad->rbroot.rb_node;

		/* Figure out where to put new node */
		while (*entry) {
			struct iova *this = container_of(*entry,
							struct iova, node);
			parent = *entry;

			if (new->pfn_lo < this->pfn_lo)
				entry = &((*entry)->rb_left);
			else if (new->pfn_lo > this->pfn_lo)
				entry = &((*entry)->rb_right);
			else
				BUG(); /* this should not happen */
		}

		/* Add new node and rebalance tree. */
		rb_link_node(&new->node, parent, entry);
		rb_insert_color(&new->node, &iovad->rbroot);
	}
	__cached_rbnode_insert_update(iovad, saved_pfn, new);

	spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);


	return 0;
}

static void
iova_insert_rbtree(struct rb_root *root, struct iova *iova)
{
	struct rb_node **new = &(root->rb_node), *parent = NULL;
	/* Figure out where to put new node */
	while (*new) {
		struct iova *this = container_of(*new, struct iova, node);
		parent = *new;

		if (iova->pfn_lo < this->pfn_lo)
			new = &((*new)->rb_left);
		else if (iova->pfn_lo > this->pfn_lo)
			new = &((*new)->rb_right);
		else
			BUG(); /* this should not happen */
	}
	/* Add new node and rebalance tree. */
	rb_link_node(&iova->node, parent, new);
	rb_insert_color(&iova->node, root);
}

/**
 * alloc_iova - allocates an iova
 * @iovad - iova domain in question
 * @size - size of page frames to allocate
 * @limit_pfn - max limit address
 * @size_aligned - set if size_aligned address range is required
 * This function allocates an iova in the range limit_pfn to IOVA_START_PFN
 * looking from limit_pfn instead from IOVA_START_PFN. If the size_aligned
 * flag is set then the allocated address iova->pfn_lo will be naturally
 * aligned on roundup_power_of_two(size).
 */
struct iova *
alloc_iova(struct iova_domain *iovad, unsigned long size,
	unsigned long limit_pfn,
	bool size_aligned)
{
	struct iova *new_iova;
	int ret;

	new_iova = alloc_iova_mem();
	if (!new_iova)
		return NULL;

	/* If size aligned is set then round the size to
	 * to next power of two.
	 */
	if (size_aligned)
		size = __roundup_pow_of_two(size);

	ret = __alloc_and_insert_iova_range(iovad, size, limit_pfn,
			new_iova, size_aligned);

	if (ret) {
		free_iova_mem(new_iova);
		return NULL;
	}

	return new_iova;
}

/**
 * find_iova - find's an iova for a given pfn
 * @iovad - iova domain in question.
 * pfn - page frame number
 * This function finds and returns an iova belonging to the
 * given doamin which matches the given pfn.
 */
struct iova *find_iova(struct iova_domain *iovad, unsigned long pfn)
{
	unsigned long flags;
	struct rb_node *node;

	/* Take the lock so that no other thread is manipulating the rbtree */
	spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
	node = iovad->rbroot.rb_node;
	while (node) {
		struct iova *iova = container_of(node, struct iova, node);

		/* If pfn falls within iova's range, return iova */
		if ((pfn >= iova->pfn_lo) && (pfn <= iova->pfn_hi)) {
			spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
			/* We are not holding the lock while this iova
			 * is referenced by the caller as the same thread
			 * which called this function also calls __free_iova()
			 * and it is by desing that only one thread can possibly
			 * reference a particular iova and hence no conflict.
			 */
			return iova;
		}

		if (pfn < iova->pfn_lo)
			node = node->rb_left;
		else if (pfn > iova->pfn_lo)
			node = node->rb_right;
	}

	spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
	return NULL;
}

/**
 * __free_iova - frees the given iova
 * @iovad: iova domain in question.
 * @iova: iova in question.
 * Frees the given iova belonging to the giving domain
 */
void
__free_iova(struct iova_domain *iovad, struct iova *iova)
{
	unsigned long flags;

	spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
	__cached_rbnode_delete_update(iovad, iova);
	rb_erase(&iova->node, &iovad->rbroot);
	spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
	free_iova_mem(iova);
}

/**
 * free_iova - finds and frees the iova for a given pfn
 * @iovad: - iova domain in question.
 * @pfn: - pfn that is allocated previously
 * This functions finds an iova for a given pfn and then
 * frees the iova from that domain.
 */
void
free_iova(struct iova_domain *iovad, unsigned long pfn)
{
	struct iova *iova = find_iova(iovad, pfn);
	if (iova)
		__free_iova(iovad, iova);

}

/**
 * put_iova_domain - destroys the iova doamin
 * @iovad: - iova domain in question.
 * All the iova's in that domain are destroyed.
 */
void put_iova_domain(struct iova_domain *iovad)
{
	struct rb_node *node;
	unsigned long flags;

	spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
	node = rb_first(&iovad->rbroot);
	while (node) {
		struct iova *iova = container_of(node, struct iova, node);
		rb_erase(node, &iovad->rbroot);
		free_iova_mem(iova);
		node = rb_first(&iovad->rbroot);
	}
	spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
}

static int
__is_range_overlap(struct rb_node *node,
	unsigned long pfn_lo, unsigned long pfn_hi)
{
	struct iova *iova = container_of(node, struct iova, node);

	if ((pfn_lo <= iova->pfn_hi) && (pfn_hi >= iova->pfn_lo))
		return 1;
	return 0;
}

static struct iova *
__insert_new_range(struct iova_domain *iovad,
	unsigned long pfn_lo, unsigned long pfn_hi)
{
	struct iova *iova;

	iova = alloc_iova_mem();
	if (!iova)
		return iova;

	iova->pfn_hi = pfn_hi;
	iova->pfn_lo = pfn_lo;
	iova_insert_rbtree(&iovad->rbroot, iova);
	return iova;
}

static void
__adjust_overlap_range(struct iova *iova,
	unsigned long *pfn_lo, unsigned long *pfn_hi)
{
	if (*pfn_lo < iova->pfn_lo)
		iova->pfn_lo = *pfn_lo;
	if (*pfn_hi > iova->pfn_hi)
		*pfn_lo = iova->pfn_hi + 1;
}

/**
 * reserve_iova - reserves an iova in the given range
 * @iovad: - iova domain pointer
 * @pfn_lo: - lower page frame address
 * @pfn_hi:- higher pfn adderss
 * This function allocates reserves the address range from pfn_lo to pfn_hi so
 * that this address is not dished out as part of alloc_iova.
 */
struct iova *
reserve_iova(struct iova_domain *iovad,
	unsigned long pfn_lo, unsigned long pfn_hi)
{
	struct rb_node *node;
	unsigned long flags;
	struct iova *iova;
	unsigned int overlap = 0;

	spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
	for (node = rb_first(&iovad->rbroot); node; node = rb_next(node)) {
		if (__is_range_overlap(node, pfn_lo, pfn_hi)) {
			iova = container_of(node, struct iova, node);
			__adjust_overlap_range(iova, &pfn_lo, &pfn_hi);
			if ((pfn_lo >= iova->pfn_lo) &&
				(pfn_hi <= iova->pfn_hi))
				goto finish;
			overlap = 1;

		} else if (overlap)
				break;
	}

	/* We are here either because this is the first reserver node
	 * or need to insert remaining non overlap addr range
	 */
	iova = __insert_new_range(iovad, pfn_lo, pfn_hi);
finish:

	spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
	return iova;
}

/**
 * copy_reserved_iova - copies the reserved between domains
 * @from: - source doamin from where to copy
 * @to: - destination domin where to copy
 * This function copies reserved iova's from one doamin to
 * other.
 */
void
copy_reserved_iova(struct iova_domain *from, struct iova_domain *to)
{
	unsigned long flags;
	struct rb_node *node;

	spin_lock_irqsave(&from->iova_rbtree_lock, flags);
	for (node = rb_first(&from->rbroot); node; node = rb_next(node)) {
		struct iova *iova = container_of(node, struct iova, node);
		struct iova *new_iova;
		new_iova = reserve_iova(to, iova->pfn_lo, iova->pfn_hi);
		if (!new_iova)
			printk(KERN_ERR "Reserve iova range %lx@%lx failed\n",
				iova->pfn_lo, iova->pfn_lo);
	}
	spin_unlock_irqrestore(&from->iova_rbtree_lock, flags);
}
Commit	Line	Data
f8de50eb	1	/*
a15a519e	2	* Copyright © 2006-2009, Intel Corporation.
f8de50eb	3	*
a15a519e DW	4	* This program is free software; you can redistribute it and/or modify it
	5	* under the terms and conditions of the GNU General Public License,
	6	* version 2, as published by the Free Software Foundation.
	7	*
	8	* This program is distributed in the hope it will be useful, but WITHOUT
	9	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	10	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
	11	* more details.
	12	*
	13	* You should have received a copy of the GNU General Public License along with
	14	* this program; if not, write to the Free Software Foundation, Inc., 59 Temple
	15	* Place - Suite 330, Boston, MA 02111-1307 USA.
f8de50eb	16	*
98bcef56	17	* Author: Anil S Keshavamurthy <[email protected]>
f8de50eb KA	18	*/
f8de50eb KA	19
38717946	20	#include <linux/iova.h>
f8de50eb KA	21
f8de50eb KA	22	void
f661197e	23	init_iova_domain(struct iova_domain *iovad, unsigned long pfn_32bit)
f8de50eb	24	{
f8de50eb KA	25	spin_lock_init(&iovad->iova_rbtree_lock);
	26	iovad->rbroot = RB_ROOT;
	27	iovad->cached32_node = NULL;
f661197e	28	iovad->dma_32bit_pfn = pfn_32bit;
f8de50eb KA	29	}
	30
	31	static struct rb_node *
	32	__get_cached_rbnode(struct iova_domain iovad, unsigned long limit_pfn)
	33	{
f661197e	34	if ((*limit_pfn != iovad->dma_32bit_pfn) \|\|
f8de50eb KA	35	(iovad->cached32_node == NULL))
	36	return rb_last(&iovad->rbroot);
	37	else {
	38	struct rb_node *prev_node = rb_prev(iovad->cached32_node);
	39	struct iova *curr_iova =
	40	container_of(iovad->cached32_node, struct iova, node);
	41	*limit_pfn = curr_iova->pfn_lo - 1;
	42	return prev_node;
	43	}
	44	}
	45
	46	static void
	47	__cached_rbnode_insert_update(struct iova_domain *iovad,
	48	unsigned long limit_pfn, struct iova *new)
	49	{
f661197e	50	if (limit_pfn != iovad->dma_32bit_pfn)
f8de50eb KA	51	return;
	52	iovad->cached32_node = &new->node;
	53	}
	54
	55	static void
	56	__cached_rbnode_delete_update(struct iova_domain iovad, struct iova free)
	57	{
	58	struct iova *cached_iova;
	59	struct rb_node *curr;
	60
	61	if (!iovad->cached32_node)
	62	return;
	63	curr = iovad->cached32_node;
	64	cached_iova = container_of(curr, struct iova, node);
	65
1c9fc3d1 CW	66	if (free->pfn_lo >= cached_iova->pfn_lo) {
	67	struct rb_node *node = rb_next(&free->node);
	68	struct iova *iova = container_of(node, struct iova, node);
	69
	70	/* only cache if it's below 32bit pfn */
	71	if (node && iova->pfn_lo < iovad->dma_32bit_pfn)
	72	iovad->cached32_node = node;
	73	else
	74	iovad->cached32_node = NULL;
	75	}
f8de50eb KA	76	}
f8de50eb KA	77
f76aec76 KA	78	/* Computes the padding size required, to make the
	79	* the start address naturally aligned on its size
	80	*/
	81	static int
	82	iova_get_pad_size(int size, unsigned int limit_pfn)
	83	{
	84	unsigned int pad_size = 0;
	85	unsigned int order = ilog2(size);
	86
	87	if (order)
	88	pad_size = (limit_pfn + 1) % (1 << order);
	89
	90	return pad_size;
	91	}
	92
ddf02886	93	static int __alloc_and_insert_iova_range(struct iova_domain *iovad,
	94	unsigned long size, unsigned long limit_pfn,
	95	struct iova *new, bool size_aligned)
f8de50eb	96	{
ddf02886	97	struct rb_node prev, curr = NULL;
f8de50eb KA	98	unsigned long flags;
f8de50eb KA	99	unsigned long saved_pfn;
f76aec76	100	unsigned int pad_size = 0;
f8de50eb KA	101
	102	/* Walk the tree backwards */
	103	spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
	104	saved_pfn = limit_pfn;
	105	curr = __get_cached_rbnode(iovad, &limit_pfn);
ddf02886	106	prev = curr;
f8de50eb KA	107	while (curr) {
f8de50eb KA	108	struct iova *curr_iova = container_of(curr, struct iova, node);
ddf02886	109
f8de50eb KA	110	if (limit_pfn < curr_iova->pfn_lo)
f8de50eb KA	111	goto move_left;
f76aec76	112	else if (limit_pfn < curr_iova->pfn_hi)
f8de50eb	113	goto adjust_limit_pfn;
f76aec76 KA	114	else {
	115	if (size_aligned)
	116	pad_size = iova_get_pad_size(size, limit_pfn);
	117	if ((curr_iova->pfn_hi + size + pad_size) <= limit_pfn)
	118	break; /* found a free slot */
	119	}
f8de50eb KA	120	adjust_limit_pfn:
	121	limit_pfn = curr_iova->pfn_lo - 1;
	122	move_left:
ddf02886	123	prev = curr;
f8de50eb KA	124	curr = rb_prev(curr);
	125	}
	126
f76aec76 KA	127	if (!curr) {
	128	if (size_aligned)
	129	pad_size = iova_get_pad_size(size, limit_pfn);
	130	if ((IOVA_START_PFN + size + pad_size) > limit_pfn) {
	131	spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
	132	return -ENOMEM;
	133	}
f8de50eb	134	}
f76aec76 KA	135
	136	/* pfn_lo will point to size aligned address if size_aligned is set */
	137	new->pfn_lo = limit_pfn - (size + pad_size) + 1;
	138	new->pfn_hi = new->pfn_lo + size - 1;
f8de50eb	139
ddf02886	140	/* Insert the new_iova into domain rbtree by holding writer lock */
	141	/* Add new node and rebalance tree. */
	142	{
a15a519e DW	143	struct rb_node *entry, parent = NULL;
	144
	145	/* If we have 'prev', it's a valid place to start the
	146	insertion. Otherwise, start from the root. */
	147	if (prev)
	148	entry = &prev;
	149	else
	150	entry = &iovad->rbroot.rb_node;
	151
ddf02886	152	/* Figure out where to put new node */
	153	while (*entry) {
	154	struct iova this = container_of(entry,
	155	struct iova, node);
	156	parent = *entry;
	157
	158	if (new->pfn_lo < this->pfn_lo)
	159	entry = &((*entry)->rb_left);
	160	else if (new->pfn_lo > this->pfn_lo)
	161	entry = &((*entry)->rb_right);
	162	else
	163	BUG(); /* this should not happen */
	164	}
	165
	166	/* Add new node and rebalance tree. */
	167	rb_link_node(&new->node, parent, entry);
	168	rb_insert_color(&new->node, &iovad->rbroot);
	169	}
	170	__cached_rbnode_insert_update(iovad, saved_pfn, new);
	171
f8de50eb	172	spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
ddf02886	173
ddf02886	174
f8de50eb KA	175	return 0;
	176	}
	177
	178	static void
	179	iova_insert_rbtree(struct rb_root root, struct iova iova)
	180	{
	181	struct rb_node *new = &(root->rb_node), parent = NULL;
	182	/* Figure out where to put new node */
	183	while (*new) {
	184	struct iova this = container_of(new, struct iova, node);
	185	parent = *new;
	186
	187	if (iova->pfn_lo < this->pfn_lo)
	188	new = &((*new)->rb_left);
	189	else if (iova->pfn_lo > this->pfn_lo)
	190	new = &((*new)->rb_right);
	191	else
	192	BUG(); /* this should not happen */
	193	}
	194	/* Add new node and rebalance tree. */
	195	rb_link_node(&iova->node, parent, new);
	196	rb_insert_color(&iova->node, root);
	197	}
	198
	199	/**
	200	* alloc_iova - allocates an iova
	201	* @iovad - iova domain in question
	202	* @size - size of page frames to allocate
	203	* @limit_pfn - max limit address
f76aec76	204	* @size_aligned - set if size_aligned address range is required
f8de50eb	205	* This function allocates an iova in the range limit_pfn to IOVA_START_PFN
f76aec76 KA	206	* looking from limit_pfn instead from IOVA_START_PFN. If the size_aligned
	207	* flag is set then the allocated address iova->pfn_lo will be naturally
	208	* aligned on roundup_power_of_two(size).
f8de50eb KA	209	*/
	210	struct iova *
	211	alloc_iova(struct iova_domain *iovad, unsigned long size,
f76aec76 KA	212	unsigned long limit_pfn,
f76aec76 KA	213	bool size_aligned)
f8de50eb	214	{
f8de50eb KA	215	struct iova *new_iova;
	216	int ret;
	217
	218	new_iova = alloc_iova_mem();
	219	if (!new_iova)
	220	return NULL;
	221
f76aec76 KA	222	/* If size aligned is set then round the size to
	223	* to next power of two.
	224	*/
	225	if (size_aligned)
	226	size = __roundup_pow_of_two(size);
	227
ddf02886	228	ret = __alloc_and_insert_iova_range(iovad, size, limit_pfn,
ddf02886	229	new_iova, size_aligned);
f8de50eb KA	230
f8de50eb KA	231	if (ret) {
f8de50eb KA	232	free_iova_mem(new_iova);
	233	return NULL;
	234	}
	235
f8de50eb KA	236	return new_iova;
	237	}
	238
	239	/**
	240	* find_iova - find's an iova for a given pfn
	241	* @iovad - iova domain in question.
	242	* pfn - page frame number
	243	* This function finds and returns an iova belonging to the
	244	* given doamin which matches the given pfn.
	245	*/
	246	struct iova find_iova(struct iova_domain iovad, unsigned long pfn)
	247	{
	248	unsigned long flags;
	249	struct rb_node *node;
	250
	251	/* Take the lock so that no other thread is manipulating the rbtree */
	252	spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
	253	node = iovad->rbroot.rb_node;
	254	while (node) {
	255	struct iova *iova = container_of(node, struct iova, node);
	256
	257	/* If pfn falls within iova's range, return iova */
	258	if ((pfn >= iova->pfn_lo) && (pfn <= iova->pfn_hi)) {
	259	spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
	260	/* We are not holding the lock while this iova
	261	* is referenced by the caller as the same thread
	262	* which called this function also calls __free_iova()
	263	* and it is by desing that only one thread can possibly
	264	* reference a particular iova and hence no conflict.
	265	*/
	266	return iova;
	267	}
	268
	269	if (pfn < iova->pfn_lo)
	270	node = node->rb_left;
	271	else if (pfn > iova->pfn_lo)
	272	node = node->rb_right;
	273	}
	274
	275	spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
	276	return NULL;
	277	}
	278
	279	/**
	280	* __free_iova - frees the given iova
	281	* @iovad: iova domain in question.
	282	* @iova: iova in question.
	283	* Frees the given iova belonging to the giving domain
	284	*/
	285	void
	286	__free_iova(struct iova_domain iovad, struct iova iova)
	287	{
	288	unsigned long flags;
	289
	290	spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
	291	__cached_rbnode_delete_update(iovad, iova);
	292	rb_erase(&iova->node, &iovad->rbroot);
	293	spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
	294	free_iova_mem(iova);
	295	}
	296
	297	/**
	298	* free_iova - finds and frees the iova for a given pfn
	299	* @iovad: - iova domain in question.
300	* @pfn: - pfn that is allocated previously
301	* This functions finds an iova for a given pfn and then
302	* frees the iova from that domain.
303	*/
304	void
305	free_iova(struct iova_domain *iovad, unsigned long pfn)
306	{
307	struct iova *iova = find_iova(iovad, pfn);
308	if (iova)
309	__free_iova(iovad, iova);
310
311	}
312
313	/**
314	* put_iova_domain - destroys the iova doamin
315	* @iovad: - iova domain in question.
316	* All the iova's in that domain are destroyed.
317	*/
318	void put_iova_domain(struct iova_domain *iovad)
319	{
320	struct rb_node *node;
321	unsigned long flags;
322
323	spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
324	node = rb_first(&iovad->rbroot);
325	while (node) {
326	struct iova *iova = container_of(node, struct iova, node);
327	rb_erase(node, &iovad->rbroot);
328	free_iova_mem(iova);
329	node = rb_first(&iovad->rbroot);
330	}
331	spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
332	}
333
334	static int
335	__is_range_overlap(struct rb_node *node,
336	unsigned long pfn_lo, unsigned long pfn_hi)
337	{
338	struct iova *iova = container_of(node, struct iova, node);
339
340	if ((pfn_lo <= iova->pfn_hi) && (pfn_hi >= iova->pfn_lo))
341	return 1;
342	return 0;
343	}
344
345	static struct iova *
346	__insert_new_range(struct iova_domain *iovad,
347	unsigned long pfn_lo, unsigned long pfn_hi)
348	{
349	struct iova *iova;
350
351	iova = alloc_iova_mem();
352	if (!iova)
353	return iova;
354
355	iova->pfn_hi = pfn_hi;
356	iova->pfn_lo = pfn_lo;
357	iova_insert_rbtree(&iovad->rbroot, iova);
358	return iova;
359	}
360
361	static void
362	__adjust_overlap_range(struct iova *iova,
363	unsigned long pfn_lo, unsigned long pfn_hi)
364	{
365	if (*pfn_lo < iova->pfn_lo)
366	iova->pfn_lo = *pfn_lo;
367	if (*pfn_hi > iova->pfn_hi)
368	*pfn_lo = iova->pfn_hi + 1;
369	}
370
371	/**
372	* reserve_iova - reserves an iova in the given range
373	* @iovad: - iova domain pointer
374	* @pfn_lo: - lower page frame address
375	* @pfn_hi:- higher pfn adderss
376	* This function allocates reserves the address range from pfn_lo to pfn_hi so
377	* that this address is not dished out as part of alloc_iova.
378	*/
379	struct iova *
380	reserve_iova(struct iova_domain *iovad,
381	unsigned long pfn_lo, unsigned long pfn_hi)
382	{
383	struct rb_node *node;
384	unsigned long flags;
385	struct iova *iova;
386	unsigned int overlap = 0;
387
3d39cecc	388	spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
f8de50eb KA	389	for (node = rb_first(&iovad->rbroot); node; node = rb_next(node)) {
	390	if (__is_range_overlap(node, pfn_lo, pfn_hi)) {
	391	iova = container_of(node, struct iova, node);
	392	__adjust_overlap_range(iova, &pfn_lo, &pfn_hi);
	393	if ((pfn_lo >= iova->pfn_lo) &&
	394	(pfn_hi <= iova->pfn_hi))
	395	goto finish;
	396	overlap = 1;
	397
	398	} else if (overlap)
	399	break;
	400	}
	401
25985edc	402	/* We are here either because this is the first reserver node
f8de50eb KA	403	* or need to insert remaining non overlap addr range
	404	*/
	405	iova = __insert_new_range(iovad, pfn_lo, pfn_hi);
	406	finish:
	407
3d39cecc	408	spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags);
f8de50eb KA	409	return iova;
	410	}
	411
	412	/**
	413	* copy_reserved_iova - copies the reserved between domains
	414	* @from: - source doamin from where to copy
	415	* @to: - destination domin where to copy
	416	* This function copies reserved iova's from one doamin to
	417	* other.
	418	*/
	419	void
	420	copy_reserved_iova(struct iova_domain from, struct iova_domain to)
	421	{
	422	unsigned long flags;
	423	struct rb_node *node;
	424
3d39cecc	425	spin_lock_irqsave(&from->iova_rbtree_lock, flags);
f8de50eb KA	426	for (node = rb_first(&from->rbroot); node; node = rb_next(node)) {
	427	struct iova *iova = container_of(node, struct iova, node);
	428	struct iova *new_iova;
	429	new_iova = reserve_iova(to, iova->pfn_lo, iova->pfn_hi);
	430	if (!new_iova)
	431	printk(KERN_ERR "Reserve iova range %lx@%lx failed\n",
	432	iova->pfn_lo, iova->pfn_lo);
	433	}
3d39cecc	434	spin_unlock_irqrestore(&from->iova_rbtree_lock, flags);
f8de50eb	435	}