[deliverable/linux.git] / drivers / staging / rdma / hfi1 / mmu_rb.c

/*
 * Copyright(c) 2016 Intel Corporation.
 *
 * This file is provided under a dual BSD/GPLv2 license.  When using or
 * redistributing this file, you may do so under either license.
 *
 * GPL LICENSE SUMMARY
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of version 2 of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that 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.
 *
 * BSD LICENSE
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *  - Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *  - Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *  - Neither the name of Intel Corporation nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */
#include <linux/list.h>
#include <linux/mmu_notifier.h>
#include <linux/rbtree.h>

#include "mmu_rb.h"
#include "trace.h"

struct mmu_rb_handler {
	struct list_head list;
	struct mmu_notifier mn;
	struct rb_root *root;
	spinlock_t lock;        /* protect the RB tree */
	struct mmu_rb_ops *ops;
};

static LIST_HEAD(mmu_rb_handlers);
static DEFINE_SPINLOCK(mmu_rb_lock); /* protect mmu_rb_handlers list */

static struct mmu_rb_handler *find_mmu_handler(struct rb_root *);
static inline void mmu_notifier_page(struct mmu_notifier *, struct mm_struct *,
				     unsigned long);
static inline void mmu_notifier_range_start(struct mmu_notifier *,
					    struct mm_struct *,
					    unsigned long, unsigned long);
static void mmu_notifier_mem_invalidate(struct mmu_notifier *,
					unsigned long, unsigned long);
static struct mmu_rb_node *__mmu_rb_search(struct mmu_rb_handler *,
					   unsigned long, unsigned long);

static struct mmu_notifier_ops mn_opts = {
	.invalidate_page = mmu_notifier_page,
	.invalidate_range_start = mmu_notifier_range_start,
};

int hfi1_mmu_rb_register(struct rb_root *root, struct mmu_rb_ops *ops)
{
	struct mmu_rb_handler *handlr;
	unsigned long flags;

	if (!ops->compare || !ops->invalidate)
		return -EINVAL;

	handlr = kmalloc(sizeof(*handlr), GFP_KERNEL);
	if (!handlr)
		return -ENOMEM;

	handlr->root = root;
	handlr->ops = ops;
	INIT_HLIST_NODE(&handlr->mn.hlist);
	spin_lock_init(&handlr->lock);
	handlr->mn.ops = &mn_opts;
	spin_lock_irqsave(&mmu_rb_lock, flags);
	list_add_tail(&handlr->list, &mmu_rb_handlers);
	spin_unlock_irqrestore(&mmu_rb_lock, flags);

	return mmu_notifier_register(&handlr->mn, current->mm);
}

void hfi1_mmu_rb_unregister(struct rb_root *root)
{
	struct mmu_rb_handler *handler = find_mmu_handler(root);
	unsigned long flags;

	spin_lock_irqsave(&mmu_rb_lock, flags);
	list_del(&handler->list);
	spin_unlock_irqrestore(&mmu_rb_lock, flags);

	if (!RB_EMPTY_ROOT(root)) {
		struct rb_node *node;
		struct mmu_rb_node *rbnode;

		while ((node = rb_first(root))) {
			rbnode = rb_entry(node, struct mmu_rb_node, node);
			if (handler->ops->remove)
				handler->ops->remove(root, rbnode);
			rb_erase(node, root);
			kfree(rbnode);
		}
	}

	if (current->mm)
		mmu_notifier_unregister(&handler->mn, current->mm);
	kfree(handler);
}

int hfi1_mmu_rb_insert(struct rb_root *root, struct mmu_rb_node *mnode)
{
	struct rb_node **new, *parent = NULL;
	struct mmu_rb_handler *handler = find_mmu_handler(root);
	struct mmu_rb_node *this;
	unsigned long flags;
	int res, ret = 0;

	if (!handler)
		return -EINVAL;

	new = &handler->root->rb_node;
	spin_lock_irqsave(&handler->lock, flags);
	while (*new) {
		this = container_of(*new, struct mmu_rb_node, node);
		res = handler->ops->compare(this, mnode->addr, mnode->len);
		parent = *new;

		if (res < 0) {
			new = &((*new)->rb_left);
		} else if (res > 0) {
			new = &((*new)->rb_right);
		} else {
			ret = 1;
			goto unlock;
		}
	}

	if (handler->ops->insert) {
		ret = handler->ops->insert(root, mnode);
		if (ret)
			goto unlock;
	}

	rb_link_node(&mnode->node, parent, new);
	rb_insert_color(&mnode->node, root);
unlock:
	spin_unlock_irqrestore(&handler->lock, flags);
	return ret;
}

/* Caller must host handler lock */
static struct mmu_rb_node *__mmu_rb_search(struct mmu_rb_handler *handler,
					   unsigned long addr,
					   unsigned long len)
{
	struct rb_node *node = handler->root->rb_node;
	struct mmu_rb_node *mnode;
	int res;

	while (node) {
		mnode = container_of(node, struct mmu_rb_node, node);
		res = handler->ops->compare(mnode, addr, len);

		if (res < 0)
			node = node->rb_left;
		else if (res > 0)
			node = node->rb_right;
		else
			return mnode;
	}
	return NULL;
}

static void __mmu_rb_remove(struct mmu_rb_handler *handler,
			    struct mmu_rb_node *node)
{
	/* Validity of handler and node pointers has been checked by caller. */
	if (handler->ops->remove)
		handler->ops->remove(handler->root, node);
	rb_erase(&node->node, handler->root);
}

struct mmu_rb_node *hfi1_mmu_rb_search(struct rb_root *root, unsigned long addr,
				       unsigned long len)
{
	struct mmu_rb_handler *handler = find_mmu_handler(root);
	struct mmu_rb_node *node;
	unsigned long flags;

	if (!handler)
		return ERR_PTR(-EINVAL);

	spin_lock_irqsave(&handler->lock, flags);
	node = __mmu_rb_search(handler, addr, len);
	spin_unlock_irqrestore(&handler->lock, flags);

	return node;
}

void hfi1_mmu_rb_remove(struct rb_root *root, struct mmu_rb_node *node)
{
	struct mmu_rb_handler *handler = find_mmu_handler(root);
	unsigned long flags;

	if (!handler || !node)
		return;

	spin_lock_irqsave(&handler->lock, flags);
	__mmu_rb_remove(handler, node);
	spin_unlock_irqrestore(&handler->lock, flags);
}

static struct mmu_rb_handler *find_mmu_handler(struct rb_root *root)
{
	struct mmu_rb_handler *handler;
	unsigned long flags;

	spin_lock_irqsave(&mmu_rb_lock, flags);
	list_for_each_entry(handler, &mmu_rb_handlers, list) {
		if (handler->root == root)
			goto unlock;
	}
	handler = NULL;
unlock:
	spin_unlock_irqrestore(&mmu_rb_lock, flags);
	return handler;
}

static inline void mmu_notifier_page(struct mmu_notifier *mn,
				     struct mm_struct *mm, unsigned long addr)
{
	mmu_notifier_mem_invalidate(mn, addr, addr + PAGE_SIZE);
}

static inline void mmu_notifier_range_start(struct mmu_notifier *mn,
					    struct mm_struct *mm,
					    unsigned long start,
					    unsigned long end)
{
	mmu_notifier_mem_invalidate(mn, start, end);
}

static void mmu_notifier_mem_invalidate(struct mmu_notifier *mn,
					unsigned long start, unsigned long end)
{
	struct mmu_rb_handler *handler =
		container_of(mn, struct mmu_rb_handler, mn);
	struct rb_root *root = handler->root;
	struct mmu_rb_node *node;
	unsigned long addr = start, flags;

	spin_lock_irqsave(&handler->lock, flags);
	while (addr < end) {
		/*
		 * There is no good way to provide a reasonable length to the
		 * search function at this point. Using the remaining length in
		 * the invalidation range is not the right thing to do.
		 * We have to rely on the fact that the insertion algorithm
		 * takes care of any overlap or length restrictions by using the
		 * actual size of each node. Therefore, we can use a page as an
		 * arbitrary, non-zero value.
		 */
		node = __mmu_rb_search(handler, addr, PAGE_SIZE);

		if (!node) {
			/*
			 * Didn't find a node at this address. However, the
			 * range could be bigger than what we have registered
			 * so we have to keep looking.
			 */
			addr += PAGE_SIZE;
			continue;
		}
		if (handler->ops->invalidate(root, node))
			__mmu_rb_remove(handler, node);

		/*
		 * The next address to be looked up is computed based
		 * on the node's starting address. This is due to the
		 * fact that the range where we start might be in the
		 * middle of the node's buffer so simply incrementing
		 * the address by the node's size would result is a
		 * bad address.
		 */
		addr = node->addr + node->len;
	}
	spin_unlock_irqrestore(&handler->lock, flags);
}
Commit	Line	Data
06e0ffa6 MH	1	/*
	2	* Copyright(c) 2016 Intel Corporation.
	3	*
	4	* This file is provided under a dual BSD/GPLv2 license. When using or
	5	* redistributing this file, you may do so under either license.
	6	*
	7	* GPL LICENSE SUMMARY
	8	*
	9	* This program is free software; you can redistribute it and/or modify
	10	* it under the terms of version 2 of the GNU General Public License as
	11	* published by the Free Software Foundation.
	12	*
	13	* This program is distributed in the hope that it will be useful, but
	14	* WITHOUT ANY WARRANTY; without even the implied warranty of
	15	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	16	* General Public License for more details.
	17	*
	18	* BSD LICENSE
	19	*
	20	* Redistribution and use in source and binary forms, with or without
	21	* modification, are permitted provided that the following conditions
	22	* are met:
	23	*
	24	* - Redistributions of source code must retain the above copyright
	25	* notice, this list of conditions and the following disclaimer.
	26	* - Redistributions in binary form must reproduce the above copyright
	27	* notice, this list of conditions and the following disclaimer in
	28	* the documentation and/or other materials provided with the
	29	* distribution.
	30	* - Neither the name of Intel Corporation nor the names of its
	31	* contributors may be used to endorse or promote products derived
	32	* from this software without specific prior written permission.
	33	*
	34	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	35	* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	36	* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
	37	* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
	38	* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	39	* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
	40	* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	41	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	42	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	43	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
	44	* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	45	*
	46	*/
	47	#include <linux/list.h>
	48	#include <linux/mmu_notifier.h>
	49	#include <linux/rbtree.h>
	50
	51	#include "mmu_rb.h"
	52	#include "trace.h"
	53
	54	struct mmu_rb_handler {
	55	struct list_head list;
	56	struct mmu_notifier mn;
	57	struct rb_root *root;
	58	spinlock_t lock; /* protect the RB tree */
	59	struct mmu_rb_ops *ops;
	60	};
	61
	62	static LIST_HEAD(mmu_rb_handlers);
	63	static DEFINE_SPINLOCK(mmu_rb_lock); /* protect mmu_rb_handlers list */
	64
65	static struct mmu_rb_handler find_mmu_handler(struct rb_root );
66	static inline void mmu_notifier_page(struct mmu_notifier , struct mm_struct ,
67	unsigned long);
68	static inline void mmu_notifier_range_start(struct mmu_notifier *,
69	struct mm_struct *,
70	unsigned long, unsigned long);
71	static void mmu_notifier_mem_invalidate(struct mmu_notifier *,
72	unsigned long, unsigned long);
73	static struct mmu_rb_node __mmu_rb_search(struct mmu_rb_handler ,
74	unsigned long, unsigned long);
75
76	static struct mmu_notifier_ops mn_opts = {
77	.invalidate_page = mmu_notifier_page,
78	.invalidate_range_start = mmu_notifier_range_start,
79	};
80
81	int hfi1_mmu_rb_register(struct rb_root root, struct mmu_rb_ops ops)
82	{
83	struct mmu_rb_handler *handlr;
c81e1f64	84	unsigned long flags;
06e0ffa6 MH	85
	86	if (!ops->compare \|\| !ops->invalidate)
	87	return -EINVAL;
	88
	89	handlr = kmalloc(sizeof(*handlr), GFP_KERNEL);
	90	if (!handlr)
	91	return -ENOMEM;
	92
	93	handlr->root = root;
	94	handlr->ops = ops;
	95	INIT_HLIST_NODE(&handlr->mn.hlist);
	96	spin_lock_init(&handlr->lock);
	97	handlr->mn.ops = &mn_opts;
c81e1f64	98	spin_lock_irqsave(&mmu_rb_lock, flags);
06e0ffa6	99	list_add_tail(&handlr->list, &mmu_rb_handlers);
c81e1f64	100	spin_unlock_irqrestore(&mmu_rb_lock, flags);
06e0ffa6 MH	101
	102	return mmu_notifier_register(&handlr->mn, current->mm);
	103	}
	104
	105	void hfi1_mmu_rb_unregister(struct rb_root *root)
	106	{
	107	struct mmu_rb_handler *handler = find_mmu_handler(root);
c81e1f64	108	unsigned long flags;
06e0ffa6	109
c81e1f64	110	spin_lock_irqsave(&mmu_rb_lock, flags);
06e0ffa6	111	list_del(&handler->list);
c81e1f64	112	spin_unlock_irqrestore(&mmu_rb_lock, flags);
06e0ffa6 MH	113
	114	if (!RB_EMPTY_ROOT(root)) {
	115	struct rb_node *node;
	116	struct mmu_rb_node *rbnode;
	117
	118	while ((node = rb_first(root))) {
	119	rbnode = rb_entry(node, struct mmu_rb_node, node);
	120	if (handler->ops->remove)
	121	handler->ops->remove(root, rbnode);
	122	rb_erase(node, root);
	123	kfree(rbnode);
	124	}
	125	}
	126
	127	if (current->mm)
	128	mmu_notifier_unregister(&handler->mn, current->mm);
	129	kfree(handler);
	130	}
	131
	132	int hfi1_mmu_rb_insert(struct rb_root root, struct mmu_rb_node mnode)
	133	{
	134	struct rb_node *new, parent = NULL;
	135	struct mmu_rb_handler *handler = find_mmu_handler(root);
	136	struct mmu_rb_node *this;
c81e1f64	137	unsigned long flags;
06e0ffa6 MH	138	int res, ret = 0;
	139
	140	if (!handler)
	141	return -EINVAL;
	142
	143	new = &handler->root->rb_node;
c81e1f64	144	spin_lock_irqsave(&handler->lock, flags);
06e0ffa6 MH	145	while (*new) {
	146	this = container_of(*new, struct mmu_rb_node, node);
	147	res = handler->ops->compare(this, mnode->addr, mnode->len);
	148	parent = *new;
	149
	150	if (res < 0) {
	151	new = &((*new)->rb_left);
	152	} else if (res > 0) {
	153	new = &((*new)->rb_right);
	154	} else {
	155	ret = 1;
	156	goto unlock;
	157	}
	158	}
	159
	160	if (handler->ops->insert) {
	161	ret = handler->ops->insert(root, mnode);
	162	if (ret)
	163	goto unlock;
	164	}
	165
	166	rb_link_node(&mnode->node, parent, new);
	167	rb_insert_color(&mnode->node, root);
	168	unlock:
c81e1f64	169	spin_unlock_irqrestore(&handler->lock, flags);
06e0ffa6 MH	170	return ret;
	171	}
	172
	173	/* Caller must host handler lock */
	174	static struct mmu_rb_node __mmu_rb_search(struct mmu_rb_handler handler,
	175	unsigned long addr,
	176	unsigned long len)
	177	{
	178	struct rb_node *node = handler->root->rb_node;
	179	struct mmu_rb_node *mnode;
	180	int res;
	181
	182	while (node) {
	183	mnode = container_of(node, struct mmu_rb_node, node);
	184	res = handler->ops->compare(mnode, addr, len);
	185
	186	if (res < 0)
	187	node = node->rb_left;
	188	else if (res > 0)
	189	node = node->rb_right;
	190	else
	191	return mnode;
	192	}
	193	return NULL;
	194	}
	195
	196	static void __mmu_rb_remove(struct mmu_rb_handler *handler,
	197	struct mmu_rb_node *node)
	198	{
	199	/* Validity of handler and node pointers has been checked by caller. */
	200	if (handler->ops->remove)
	201	handler->ops->remove(handler->root, node);
	202	rb_erase(&node->node, handler->root);
	203	}
	204
	205	struct mmu_rb_node hfi1_mmu_rb_search(struct rb_root root, unsigned long addr,
	206	unsigned long len)
	207	{
	208	struct mmu_rb_handler *handler = find_mmu_handler(root);
	209	struct mmu_rb_node *node;
c81e1f64	210	unsigned long flags;
06e0ffa6 MH	211
	212	if (!handler)
	213	return ERR_PTR(-EINVAL);
	214
c81e1f64	215	spin_lock_irqsave(&handler->lock, flags);
06e0ffa6	216	node = __mmu_rb_search(handler, addr, len);
c81e1f64	217	spin_unlock_irqrestore(&handler->lock, flags);
06e0ffa6 MH	218
	219	return node;
	220	}
	221
	222	void hfi1_mmu_rb_remove(struct rb_root root, struct mmu_rb_node node)
	223	{
	224	struct mmu_rb_handler *handler = find_mmu_handler(root);
c81e1f64	225	unsigned long flags;
06e0ffa6 MH	226
	227	if (!handler \|\| !node)
	228	return;
	229
c81e1f64	230	spin_lock_irqsave(&handler->lock, flags);
06e0ffa6	231	__mmu_rb_remove(handler, node);
c81e1f64	232	spin_unlock_irqrestore(&handler->lock, flags);
06e0ffa6 MH	233	}
	234
	235	static struct mmu_rb_handler find_mmu_handler(struct rb_root root)
	236	{
	237	struct mmu_rb_handler *handler;
c81e1f64	238	unsigned long flags;
06e0ffa6	239
c81e1f64	240	spin_lock_irqsave(&mmu_rb_lock, flags);
06e0ffa6 MH	241	list_for_each_entry(handler, &mmu_rb_handlers, list) {
	242	if (handler->root == root)
	243	goto unlock;
	244	}
	245	handler = NULL;
	246	unlock:
c81e1f64	247	spin_unlock_irqrestore(&mmu_rb_lock, flags);
06e0ffa6 MH	248	return handler;
	249	}
	250
	251	static inline void mmu_notifier_page(struct mmu_notifier *mn,
	252	struct mm_struct *mm, unsigned long addr)
	253	{
	254	mmu_notifier_mem_invalidate(mn, addr, addr + PAGE_SIZE);
	255	}
	256
	257	static inline void mmu_notifier_range_start(struct mmu_notifier *mn,
	258	struct mm_struct *mm,
	259	unsigned long start,
	260	unsigned long end)
	261	{
	262	mmu_notifier_mem_invalidate(mn, start, end);
	263	}
	264
	265	static void mmu_notifier_mem_invalidate(struct mmu_notifier *mn,
	266	unsigned long start, unsigned long end)
	267	{
	268	struct mmu_rb_handler *handler =
	269	container_of(mn, struct mmu_rb_handler, mn);
	270	struct rb_root *root = handler->root;
	271	struct mmu_rb_node *node;
c81e1f64	272	unsigned long addr = start, flags;
06e0ffa6	273
c81e1f64	274	spin_lock_irqsave(&handler->lock, flags);
06e0ffa6 MH	275	while (addr < end) {
	276	/*
	277	* There is no good way to provide a reasonable length to the
	278	* search function at this point. Using the remaining length in
	279	* the invalidation range is not the right thing to do.
	280	* We have to rely on the fact that the insertion algorithm
	281	* takes care of any overlap or length restrictions by using the
	282	* actual size of each node. Therefore, we can use a page as an
	283	* arbitrary, non-zero value.
	284	*/
	285	node = __mmu_rb_search(handler, addr, PAGE_SIZE);
	286
	287	if (!node) {
	288	/*
	289	* Didn't find a node at this address. However, the
	290	* range could be bigger than what we have registered
	291	* so we have to keep looking.
	292	*/
	293	addr += PAGE_SIZE;
	294	continue;
	295	}
	296	if (handler->ops->invalidate(root, node))
	297	__mmu_rb_remove(handler, node);
	298
	299	/*
	300	* The next address to be looked up is computed based
	301	* on the node's starting address. This is due to the
	302	* fact that the range where we start might be in the
	303	* middle of the node's buffer so simply incrementing
	304	* the address by the node's size would result is a
	305	* bad address.
	306	*/
	307	addr = node->addr + node->len;
	308	}
c81e1f64	309	spin_unlock_irqrestore(&handler->lock, flags);
06e0ffa6	310	}