drivers/infiniband/hw/hfi1/mmu_rb.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
 /*
  * Copyright(c) 2020 Cornelis Networks, Inc.
  * Copyright(c) 2016 - 2017 Intel Corporation.
  */

 #include <linux/list.h>
 #include <linux/rculist.h>
 #include <linux/mmu_notifier.h>
 #include <linux/interval_tree_generic.h>
 #include <linux/sched/mm.h>

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

 static unsigned long mmu_node_start(struct mmu_rb_node *);
 static unsigned long mmu_node_last(struct mmu_rb_node *);
 static int mmu_notifier_range_start(struct mmu_notifier *,
 		const struct mmu_notifier_range *);
 static struct mmu_rb_node *__mmu_rb_search(struct mmu_rb_handler *,
 					   unsigned long, unsigned long);
 static void release_immediate(struct kref *refcount);
 static void handle_remove(struct work_struct *work);

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

 INTERVAL_TREE_DEFINE(struct mmu_rb_node, node, unsigned long, __last,
 		     mmu_node_start, mmu_node_last, static, __mmu_int_rb);

 static unsigned long mmu_node_start(struct mmu_rb_node *node)
 {
 	return node->addr & PAGE_MASK;
 }

 static unsigned long mmu_node_last(struct mmu_rb_node *node)
 {
 	return PAGE_ALIGN(node->addr + node->len) - 1;
 }

 int hfi1_mmu_rb_register(void *ops_arg,
 			 struct mmu_rb_ops *ops,
 			 struct workqueue_struct *wq,
 			 struct mmu_rb_handler **handler)
 {
 	struct mmu_rb_handler *h;
 	void *free_ptr;
 	int ret;

 	free_ptr = kzalloc(sizeof(*h) + cache_line_size() - 1, GFP_KERNEL);
 	if (!free_ptr)
 		return -ENOMEM;

 	h = PTR_ALIGN(free_ptr, cache_line_size());
 	h->root = RB_ROOT_CACHED;
 	h->ops = ops;
 	h->ops_arg = ops_arg;
 	INIT_HLIST_NODE(&h->mn.hlist);
 	spin_lock_init(&h->lock);
 	h->mn.ops = &mn_opts;
 	INIT_WORK(&h->del_work, handle_remove);
 	INIT_LIST_HEAD(&h->del_list);
 	INIT_LIST_HEAD(&h->lru_list);
 	h->wq = wq;
 	h->free_ptr = free_ptr;

 	ret = mmu_notifier_register(&h->mn, current->mm);
 	if (ret) {
 		kfree(free_ptr);
 		return ret;
 	}

 	*handler = h;
 	return 0;
 }

 void hfi1_mmu_rb_unregister(struct mmu_rb_handler *handler)
 {
 	struct mmu_rb_node *rbnode;
 	struct rb_node *node;
 	unsigned long flags;
 	struct list_head del_list;

 	/* Prevent freeing of mm until we are completely finished. */
 	mmgrab(handler->mn.mm);

 	/* Unregister first so we don't get any more notifications. */
 	mmu_notifier_unregister(&handler->mn, handler->mn.mm);

 	/*
 	 * Make sure the wq delete handler is finished running.  It will not
 	 * be triggered once the mmu notifiers are unregistered above.
 	 */
 	flush_work(&handler->del_work);

 	INIT_LIST_HEAD(&del_list);

 	spin_lock_irqsave(&handler->lock, flags);
 	while ((node = rb_first_cached(&handler->root))) {
 		rbnode = rb_entry(node, struct mmu_rb_node, node);
 		rb_erase_cached(node, &handler->root);
 		/* move from LRU list to delete list */
 		list_move(&rbnode->list, &del_list);
 	}
 	spin_unlock_irqrestore(&handler->lock, flags);

 	while (!list_empty(&del_list)) {
 		rbnode = list_first_entry(&del_list, struct mmu_rb_node, list);
 		list_del(&rbnode->list);
 		kref_put(&rbnode->refcount, release_immediate);
 	}

 	/* Now the mm may be freed. */
 	mmdrop(handler->mn.mm);

 	kfree(handler->free_ptr);
 }

 int hfi1_mmu_rb_insert(struct mmu_rb_handler *handler,
 		       struct mmu_rb_node *mnode)
 {
 	struct mmu_rb_node *node;
 	unsigned long flags;
 	int ret = 0;

 	trace_hfi1_mmu_rb_insert(mnode);

 	if (current->mm != handler->mn.mm)
 		return -EPERM;

 	spin_lock_irqsave(&handler->lock, flags);
 	node = __mmu_rb_search(handler, mnode->addr, mnode->len);
 	if (node) {
 		ret = -EEXIST;
 		goto unlock;
 	}
 	__mmu_int_rb_insert(mnode, &handler->root);
 	list_add_tail(&mnode->list, &handler->lru_list);
 	mnode->handler = handler;
 unlock:
 	spin_unlock_irqrestore(&handler->lock, flags);
 	return ret;
 }

 /* Caller must hold handler lock */
 struct mmu_rb_node *hfi1_mmu_rb_get_first(struct mmu_rb_handler *handler,
 					  unsigned long addr, unsigned long len)
 {
 	struct mmu_rb_node *node;

 	trace_hfi1_mmu_rb_search(addr, len);
 	node = __mmu_int_rb_iter_first(&handler->root, addr, (addr + len) - 1);
 	if (node)
 		list_move_tail(&node->list, &handler->lru_list);
 	return node;
 }

 /* Caller must hold handler lock */
 static struct mmu_rb_node *__mmu_rb_search(struct mmu_rb_handler *handler,
 					   unsigned long addr,
 					   unsigned long len)
 {
 	struct mmu_rb_node *node = NULL;

 	trace_hfi1_mmu_rb_search(addr, len);
 	if (!handler->ops->filter) {
 		node = __mmu_int_rb_iter_first(&handler->root, addr,
 					       (addr + len) - 1);
 	} else {
 		for (node = __mmu_int_rb_iter_first(&handler->root, addr,
 						    (addr + len) - 1);
 		     node;
 		     node = __mmu_int_rb_iter_next(node, addr,
 						   (addr + len) - 1)) {
 			if (handler->ops->filter(node, addr, len))
 				return node;
 		}
 	}
 	return node;
 }

 /*
  * Must NOT call while holding mnode->handler->lock.
  * mnode->handler->ops->remove() may sleep and mnode->handler->lock is a
  * spinlock.
  */
 static void release_immediate(struct kref *refcount)
 {
 	struct mmu_rb_node *mnode =
 		container_of(refcount, struct mmu_rb_node, refcount);
 	trace_hfi1_mmu_release_node(mnode);
 	mnode->handler->ops->remove(mnode->handler->ops_arg, mnode);
 }

 /* Caller must hold mnode->handler->lock */
 static void release_nolock(struct kref *refcount)
 {
 	struct mmu_rb_node *mnode =
 		container_of(refcount, struct mmu_rb_node, refcount);
 	list_move(&mnode->list, &mnode->handler->del_list);
 	queue_work(mnode->handler->wq, &mnode->handler->del_work);
 }

 /*
  * struct mmu_rb_node->refcount kref_put() callback.
  * Adds mmu_rb_node to mmu_rb_node->handler->del_list and queues
  * handler->del_work on handler->wq.
  * Does not remove mmu_rb_node from handler->lru_list or handler->rb_root.
  * Acquires mmu_rb_node->handler->lock; do not call while already holding
  * handler->lock.
  */
 void hfi1_mmu_rb_release(struct kref *refcount)
 {
 	struct mmu_rb_node *mnode =
 		container_of(refcount, struct mmu_rb_node, refcount);
 	struct mmu_rb_handler *handler = mnode->handler;
 	unsigned long flags;

 	spin_lock_irqsave(&handler->lock, flags);
 	list_move(&mnode->list, &mnode->handler->del_list);
 	spin_unlock_irqrestore(&handler->lock, flags);
 	queue_work(handler->wq, &handler->del_work);
 }

 void hfi1_mmu_rb_evict(struct mmu_rb_handler *handler, void *evict_arg)
 {
 	struct mmu_rb_node *rbnode, *ptr;
 	struct list_head del_list;
 	unsigned long flags;
 	bool stop = false;

 	if (current->mm != handler->mn.mm)
 		return;

 	INIT_LIST_HEAD(&del_list);

 	spin_lock_irqsave(&handler->lock, flags);
 	list_for_each_entry_safe(rbnode, ptr, &handler->lru_list, list) {
 		/* refcount == 1 implies mmu_rb_handler has only rbnode ref */
 		if (kref_read(&rbnode->refcount) > 1)
 			continue;

 		if (handler->ops->evict(handler->ops_arg, rbnode, evict_arg,
 					&stop)) {
 			__mmu_int_rb_remove(rbnode, &handler->root);
 			/* move from LRU list to delete list */
 			list_move(&rbnode->list, &del_list);
 		}
 		if (stop)
 			break;
 	}
 	spin_unlock_irqrestore(&handler->lock, flags);

 	list_for_each_entry_safe(rbnode, ptr, &del_list, list) {
 		trace_hfi1_mmu_rb_evict(rbnode);
 		kref_put(&rbnode->refcount, release_immediate);
 	}
 }

 static int mmu_notifier_range_start(struct mmu_notifier *mn,
 		const struct mmu_notifier_range *range)
 {
 	struct mmu_rb_handler *handler =
 		container_of(mn, struct mmu_rb_handler, mn);
 	struct rb_root_cached *root = &handler->root;
 	struct mmu_rb_node *node, *ptr = NULL;
 	unsigned long flags;

 	spin_lock_irqsave(&handler->lock, flags);
 	for (node = __mmu_int_rb_iter_first(root, range->start, range->end-1);
 	     node; node = ptr) {
 		/* Guard against node removal. */
 		ptr = __mmu_int_rb_iter_next(node, range->start,
 					     range->end - 1);
 		trace_hfi1_mmu_mem_invalidate(node);
 		/* Remove from rb tree and lru_list. */
 		__mmu_int_rb_remove(node, root);
 		list_del_init(&node->list);
 		kref_put(&node->refcount, release_nolock);
 	}
 	spin_unlock_irqrestore(&handler->lock, flags);

 	return 0;
 }

 /*
  * Work queue function to remove all nodes that have been queued up to
  * be removed.  The key feature is that mm->mmap_lock is not being held
  * and the remove callback can sleep while taking it, if needed.
  */
 static void handle_remove(struct work_struct *work)
 {
 	struct mmu_rb_handler *handler = container_of(work,
 						struct mmu_rb_handler,
 						del_work);
 	struct list_head del_list;
 	unsigned long flags;
 	struct mmu_rb_node *node;

 	/* remove anything that is queued to get removed */
 	spin_lock_irqsave(&handler->lock, flags);
 	list_replace_init(&handler->del_list, &del_list);
 	spin_unlock_irqrestore(&handler->lock, flags);

 	while (!list_empty(&del_list)) {
 		node = list_first_entry(&del_list, struct mmu_rb_node, list);
 		list_del(&node->list);
 		trace_hfi1_mmu_release_node(node);
 		handler->ops->remove(handler->ops_arg, node);
 	}
 }
	// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
	/*
	* Copyright(c) 2020 Cornelis Networks, Inc.
	* Copyright(c) 2016 - 2017 Intel Corporation.
	*/

	#include <linux/list.h>
	#include <linux/rculist.h>
	#include <linux/mmu_notifier.h>
	#include <linux/interval_tree_generic.h>
	#include <linux/sched/mm.h>

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

	static unsigned long mmu_node_start(struct mmu_rb_node *);
	static unsigned long mmu_node_last(struct mmu_rb_node *);
	static int mmu_notifier_range_start(struct mmu_notifier *,
	const struct mmu_notifier_range *);
	static struct mmu_rb_node __mmu_rb_search(struct mmu_rb_handler ,
	unsigned long, unsigned long);
	static void release_immediate(struct kref *refcount);
	static void handle_remove(struct work_struct *work);

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

	INTERVAL_TREE_DEFINE(struct mmu_rb_node, node, unsigned long, __last,
	mmu_node_start, mmu_node_last, static, __mmu_int_rb);

	static unsigned long mmu_node_start(struct mmu_rb_node *node)
	{
	return node->addr & PAGE_MASK;
	}

	static unsigned long mmu_node_last(struct mmu_rb_node *node)
	{
	return PAGE_ALIGN(node->addr + node->len) - 1;
	}

	int hfi1_mmu_rb_register(void *ops_arg,
	struct mmu_rb_ops *ops,
	struct workqueue_struct *wq,
	struct mmu_rb_handler **handler)
	{
	struct mmu_rb_handler *h;
	void *free_ptr;
	int ret;

	free_ptr = kzalloc(sizeof(*h) + cache_line_size() - 1, GFP_KERNEL);
	if (!free_ptr)
	return -ENOMEM;

	h = PTR_ALIGN(free_ptr, cache_line_size());
	h->root = RB_ROOT_CACHED;
	h->ops = ops;
	h->ops_arg = ops_arg;
	INIT_HLIST_NODE(&h->mn.hlist);
	spin_lock_init(&h->lock);
	h->mn.ops = &mn_opts;
	INIT_WORK(&h->del_work, handle_remove);
	INIT_LIST_HEAD(&h->del_list);
	INIT_LIST_HEAD(&h->lru_list);
	h->wq = wq;
	h->free_ptr = free_ptr;

	ret = mmu_notifier_register(&h->mn, current->mm);
	if (ret) {
	kfree(free_ptr);
	return ret;
	}

	*handler = h;
	return 0;
	}

	void hfi1_mmu_rb_unregister(struct mmu_rb_handler *handler)
	{
	struct mmu_rb_node *rbnode;
	struct rb_node *node;
	unsigned long flags;
	struct list_head del_list;

	/* Prevent freeing of mm until we are completely finished. */
	mmgrab(handler->mn.mm);

	/* Unregister first so we don't get any more notifications. */
	mmu_notifier_unregister(&handler->mn, handler->mn.mm);

	/*
	* Make sure the wq delete handler is finished running. It will not
	* be triggered once the mmu notifiers are unregistered above.
	*/
	flush_work(&handler->del_work);

	INIT_LIST_HEAD(&del_list);

	spin_lock_irqsave(&handler->lock, flags);
	while ((node = rb_first_cached(&handler->root))) {
	rbnode = rb_entry(node, struct mmu_rb_node, node);
	rb_erase_cached(node, &handler->root);
	/* move from LRU list to delete list */
	list_move(&rbnode->list, &del_list);
	}
	spin_unlock_irqrestore(&handler->lock, flags);

	while (!list_empty(&del_list)) {
	rbnode = list_first_entry(&del_list, struct mmu_rb_node, list);
	list_del(&rbnode->list);
	kref_put(&rbnode->refcount, release_immediate);
	}

	/* Now the mm may be freed. */
	mmdrop(handler->mn.mm);

	kfree(handler->free_ptr);
	}

	int hfi1_mmu_rb_insert(struct mmu_rb_handler *handler,
	struct mmu_rb_node *mnode)
	{
	struct mmu_rb_node *node;
	unsigned long flags;
	int ret = 0;

	trace_hfi1_mmu_rb_insert(mnode);

	if (current->mm != handler->mn.mm)
	return -EPERM;

	spin_lock_irqsave(&handler->lock, flags);
	node = __mmu_rb_search(handler, mnode->addr, mnode->len);
	if (node) {
	ret = -EEXIST;
	goto unlock;
	}
	__mmu_int_rb_insert(mnode, &handler->root);
	list_add_tail(&mnode->list, &handler->lru_list);
	mnode->handler = handler;
	unlock:
	spin_unlock_irqrestore(&handler->lock, flags);
	return ret;
	}

	/* Caller must hold handler lock */
	struct mmu_rb_node hfi1_mmu_rb_get_first(struct mmu_rb_handler handler,
	unsigned long addr, unsigned long len)
	{
	struct mmu_rb_node *node;

	trace_hfi1_mmu_rb_search(addr, len);
	node = __mmu_int_rb_iter_first(&handler->root, addr, (addr + len) - 1);
	if (node)
	list_move_tail(&node->list, &handler->lru_list);
	return node;
	}

	/* Caller must hold handler lock */
	static struct mmu_rb_node __mmu_rb_search(struct mmu_rb_handler handler,
	unsigned long addr,
	unsigned long len)
	{
	struct mmu_rb_node *node = NULL;

	trace_hfi1_mmu_rb_search(addr, len);
	if (!handler->ops->filter) {
	node = __mmu_int_rb_iter_first(&handler->root, addr,
	(addr + len) - 1);
	} else {
	for (node = __mmu_int_rb_iter_first(&handler->root, addr,
	(addr + len) - 1);
	node;
	node = __mmu_int_rb_iter_next(node, addr,
	(addr + len) - 1)) {
	if (handler->ops->filter(node, addr, len))
	return node;
	}
	}
	return node;
	}

	/*
	* Must NOT call while holding mnode->handler->lock.
	* mnode->handler->ops->remove() may sleep and mnode->handler->lock is a
	* spinlock.
	*/
	static void release_immediate(struct kref *refcount)
	{
	struct mmu_rb_node *mnode =
	container_of(refcount, struct mmu_rb_node, refcount);
	trace_hfi1_mmu_release_node(mnode);
	mnode->handler->ops->remove(mnode->handler->ops_arg, mnode);
	}

	/* Caller must hold mnode->handler->lock */
	static void release_nolock(struct kref *refcount)
	{
	struct mmu_rb_node *mnode =
	container_of(refcount, struct mmu_rb_node, refcount);
	list_move(&mnode->list, &mnode->handler->del_list);
	queue_work(mnode->handler->wq, &mnode->handler->del_work);
	}

	/*
	* struct mmu_rb_node->refcount kref_put() callback.
	* Adds mmu_rb_node to mmu_rb_node->handler->del_list and queues
	* handler->del_work on handler->wq.
	* Does not remove mmu_rb_node from handler->lru_list or handler->rb_root.
	* Acquires mmu_rb_node->handler->lock; do not call while already holding
	* handler->lock.
	*/
	void hfi1_mmu_rb_release(struct kref *refcount)
	{
	struct mmu_rb_node *mnode =
	container_of(refcount, struct mmu_rb_node, refcount);
	struct mmu_rb_handler *handler = mnode->handler;
	unsigned long flags;

	spin_lock_irqsave(&handler->lock, flags);
	list_move(&mnode->list, &mnode->handler->del_list);
	spin_unlock_irqrestore(&handler->lock, flags);
	queue_work(handler->wq, &handler->del_work);
	}

	void hfi1_mmu_rb_evict(struct mmu_rb_handler handler, void evict_arg)
	{
	struct mmu_rb_node rbnode, ptr;
	struct list_head del_list;
	unsigned long flags;
	bool stop = false;

	if (current->mm != handler->mn.mm)
	return;

	INIT_LIST_HEAD(&del_list);

	spin_lock_irqsave(&handler->lock, flags);
	list_for_each_entry_safe(rbnode, ptr, &handler->lru_list, list) {
	/* refcount == 1 implies mmu_rb_handler has only rbnode ref */
	if (kref_read(&rbnode->refcount) > 1)
	continue;

	if (handler->ops->evict(handler->ops_arg, rbnode, evict_arg,
	&stop)) {
	__mmu_int_rb_remove(rbnode, &handler->root);
	/* move from LRU list to delete list */
	list_move(&rbnode->list, &del_list);
	}
	if (stop)
	break;
	}
	spin_unlock_irqrestore(&handler->lock, flags);

	list_for_each_entry_safe(rbnode, ptr, &del_list, list) {
	trace_hfi1_mmu_rb_evict(rbnode);
	kref_put(&rbnode->refcount, release_immediate);
	}
	}

	static int mmu_notifier_range_start(struct mmu_notifier *mn,
	const struct mmu_notifier_range *range)
	{
	struct mmu_rb_handler *handler =
	container_of(mn, struct mmu_rb_handler, mn);
	struct rb_root_cached *root = &handler->root;
	struct mmu_rb_node node, ptr = NULL;
	unsigned long flags;

	spin_lock_irqsave(&handler->lock, flags);
	for (node = __mmu_int_rb_iter_first(root, range->start, range->end-1);
	node; node = ptr) {
	/* Guard against node removal. */
	ptr = __mmu_int_rb_iter_next(node, range->start,
	range->end - 1);
	trace_hfi1_mmu_mem_invalidate(node);
	/* Remove from rb tree and lru_list. */
	__mmu_int_rb_remove(node, root);
	list_del_init(&node->list);
	kref_put(&node->refcount, release_nolock);
	}
	spin_unlock_irqrestore(&handler->lock, flags);

	return 0;
	}

	/*
	* Work queue function to remove all nodes that have been queued up to
	* be removed. The key feature is that mm->mmap_lock is not being held
	* and the remove callback can sleep while taking it, if needed.
	*/
	static void handle_remove(struct work_struct *work)
	{
	struct mmu_rb_handler *handler = container_of(work,
	struct mmu_rb_handler,
	del_work);
	struct list_head del_list;
	unsigned long flags;
	struct mmu_rb_node *node;

	/* remove anything that is queued to get removed */
	spin_lock_irqsave(&handler->lock, flags);
	list_replace_init(&handler->del_list, &del_list);
	spin_unlock_irqrestore(&handler->lock, flags);

	while (!list_empty(&del_list)) {
	node = list_first_entry(&del_list, struct mmu_rb_node, list);
	list_del(&node->list);
	trace_hfi1_mmu_release_node(node);
	handler->ops->remove(handler->ops_arg, node);
	}
	}