/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_PAGE_REF_H
#define _LINUX_PAGE_REF_H

#include <linux/atomic.h>
#include <linux/mm_types.h>
#include <linux/page-flags.h>
#include <linux/tracepoint-defs.h>

DECLARE_TRACEPOINT(page_ref_set);
DECLARE_TRACEPOINT(page_ref_mod);
DECLARE_TRACEPOINT(page_ref_mod_and_test);
DECLARE_TRACEPOINT(page_ref_mod_and_return);
DECLARE_TRACEPOINT(page_ref_mod_unless);
DECLARE_TRACEPOINT(page_ref_freeze);
DECLARE_TRACEPOINT(page_ref_unfreeze);

#ifdef CONFIG_DEBUG_PAGE_REF


#define page_ref_tracepoint_active(t) tracepoint_enabled(t)

extern void __page_ref_set(struct page *page, int v);
extern void __page_ref_mod(struct page *page, int v);
extern void __page_ref_mod_and_test(struct page *page, int v, int ret);
extern void __page_ref_mod_and_return(struct page *page, int v, int ret);
extern void __page_ref_mod_unless(struct page *page, int v, int u);
extern void __page_ref_freeze(struct page *page, int v, int ret);
extern void __page_ref_unfreeze(struct page *page, int v);

#else

#define page_ref_tracepoint_active(t) false

static inline void __page_ref_set(struct page *page, int v)
{
}
static inline void __page_ref_mod(struct page *page, int v)
{
}
static inline void __page_ref_mod_and_test(struct page *page, int v, int ret)
{
}
static inline void __page_ref_mod_and_return(struct page *page, int v, int ret)
{
}
static inline void __page_ref_mod_unless(struct page *page, int v, int u)
{
}
static inline void __page_ref_freeze(struct page *page, int v, int ret)
{
}
static inline void __page_ref_unfreeze(struct page *page, int v)
{
}

#endif

static inline int page_ref_count(const struct page *page)
{
	return atomic_read(&page->_refcount);
}


static inline int folio_ref_count(const struct folio *folio)
{
	return page_ref_count(&folio->page);
}

static inline int page_count(const struct page *page)
{
	return folio_ref_count(page_folio(page));
}

static inline void set_page_count(struct page *page, int v)
{
	atomic_set(&page->_refcount, v);
	if (page_ref_tracepoint_active(page_ref_set))
		__page_ref_set(page, v);
}

static inline void folio_set_count(struct folio *folio, int v)
{
	set_page_count(&folio->page, v);
}


static inline void init_page_count(struct page *page)
{
	set_page_count(page, 1);
}

static inline void page_ref_add(struct page *page, int nr)
{
	atomic_add(nr, &page->_refcount);
	if (page_ref_tracepoint_active(page_ref_mod))
		__page_ref_mod(page, nr);
}

static inline void folio_ref_add(struct folio *folio, int nr)
{
	page_ref_add(&folio->page, nr);
}

static inline void page_ref_sub(struct page *page, int nr)
{
	atomic_sub(nr, &page->_refcount);
	if (page_ref_tracepoint_active(page_ref_mod))
		__page_ref_mod(page, -nr);
}

static inline void folio_ref_sub(struct folio *folio, int nr)
{
	page_ref_sub(&folio->page, nr);
}

static inline int page_ref_sub_return(struct page *page, int nr)
{
	int ret = atomic_sub_return(nr, &page->_refcount);

	if (page_ref_tracepoint_active(page_ref_mod_and_return))
		__page_ref_mod_and_return(page, -nr, ret);
	return ret;
}

static inline int folio_ref_sub_return(struct folio *folio, int nr)
{
	return page_ref_sub_return(&folio->page, nr);
}

static inline void page_ref_inc(struct page *page)
{
	atomic_inc(&page->_refcount);
	if (page_ref_tracepoint_active(page_ref_mod))
		__page_ref_mod(page, 1);
}

static inline void folio_ref_inc(struct folio *folio)
{
	page_ref_inc(&folio->page);
}

static inline void page_ref_dec(struct page *page)
{
	atomic_dec(&page->_refcount);
	if (page_ref_tracepoint_active(page_ref_mod))
		__page_ref_mod(page, -1);
}

static inline void folio_ref_dec(struct folio *folio)
{
	page_ref_dec(&folio->page);
}

static inline int page_ref_sub_and_test(struct page *page, int nr)
{
	int ret = atomic_sub_and_test(nr, &page->_refcount);

	if (page_ref_tracepoint_active(page_ref_mod_and_test))
		__page_ref_mod_and_test(page, -nr, ret);
	return ret;
}

static inline int folio_ref_sub_and_test(struct folio *folio, int nr)
{
	return page_ref_sub_and_test(&folio->page, nr);
}

static inline int page_ref_inc_return(struct page *page)
{
	int ret = atomic_inc_return(&page->_refcount);

	if (page_ref_tracepoint_active(page_ref_mod_and_return))
		__page_ref_mod_and_return(page, 1, ret);
	return ret;
}

static inline int folio_ref_inc_return(struct folio *folio)
{
	return page_ref_inc_return(&folio->page);
}

static inline int page_ref_dec_and_test(struct page *page)
{
	int ret = atomic_dec_and_test(&page->_refcount);

	if (page_ref_tracepoint_active(page_ref_mod_and_test))
		__page_ref_mod_and_test(page, -1, ret);
	return ret;
}

static inline int folio_ref_dec_and_test(struct folio *folio)
{
	return page_ref_dec_and_test(&folio->page);
}

static inline int page_ref_dec_return(struct page *page)
{
	int ret = atomic_dec_return(&page->_refcount);

	if (page_ref_tracepoint_active(page_ref_mod_and_return))
		__page_ref_mod_and_return(page, -1, ret);
	return ret;
}

static inline int folio_ref_dec_return(struct folio *folio)
{
	return page_ref_dec_return(&folio->page);
}

static inline bool page_ref_add_unless(struct page *page, int nr, int u)
{
	bool ret = atomic_add_unless(&page->_refcount, nr, u);

	if (page_ref_tracepoint_active(page_ref_mod_unless))
		__page_ref_mod_unless(page, nr, ret);
	return ret;
}

static inline bool folio_ref_add_unless(struct folio *folio, int nr, int u)
{
	return page_ref_add_unless(&folio->page, nr, u);
}


static inline bool folio_try_get(struct folio *folio)
{
	return folio_ref_add_unless(folio, 1, 0);
}

static inline bool folio_ref_try_add_rcu(struct folio *folio, int count)
{
#ifdef CONFIG_TINY_RCU
	
# ifdef CONFIG_PREEMPT_COUNT
	VM_BUG_ON(!in_atomic() && !irqs_disabled());
# endif
	VM_BUG_ON_FOLIO(folio_ref_count(folio) == 0, folio);
	folio_ref_add(folio, count);
#else
	if (unlikely(!folio_ref_add_unless(folio, count, 0))) {
		
		return false;
	}
#endif
	return true;
}


static inline bool folio_try_get_rcu(struct folio *folio)
{
	return folio_ref_try_add_rcu(folio, 1);
}

static inline int page_ref_freeze(struct page *page, int count)
{
	int ret = likely(atomic_cmpxchg(&page->_refcount, count, 0) == count);

	if (page_ref_tracepoint_active(page_ref_freeze))
		__page_ref_freeze(page, count, ret);
	return ret;
}

static inline int folio_ref_freeze(struct folio *folio, int count)
{
	return page_ref_freeze(&folio->page, count);
}

static inline void page_ref_unfreeze(struct page *page, int count)
{
	VM_BUG_ON_PAGE(page_count(page) != 0, page);
	VM_BUG_ON(count == 0);

	atomic_set_release(&page->_refcount, count);
	if (page_ref_tracepoint_active(page_ref_unfreeze))
		__page_ref_unfreeze(page, count);
}

static inline void folio_ref_unfreeze(struct folio *folio, int count)
{
	page_ref_unfreeze(&folio->page, count);
}
#endif
