[linux-block.git] / include / linux / pagevec.h

/* SPDX-License-Identifier: GPL-2.0 */
/*
 * include/linux/pagevec.h
 *
 * In many places it is efficient to batch an operation up against multiple
 * pages.  A pagevec is a multipage container which is used for that.
 */

#ifndef _LINUX_PAGEVEC_H
#define _LINUX_PAGEVEC_H

#include <linux/xarray.h>

/* 15 pointers + header align the pagevec structure to a power of two */
#define PAGEVEC_SIZE	15

struct page;
struct folio;
struct address_space;

/* Layout must match folio_batch */
struct pagevec {
	unsigned char nr;
	bool percpu_pvec_drained;
	struct page *pages[PAGEVEC_SIZE];
};

void __pagevec_release(struct pagevec *pvec);

static inline void pagevec_init(struct pagevec *pvec)
{
	pvec->nr = 0;
	pvec->percpu_pvec_drained = false;
}

static inline void pagevec_reinit(struct pagevec *pvec)
{
	pvec->nr = 0;
}

static inline unsigned pagevec_count(struct pagevec *pvec)
{
	return pvec->nr;
}

static inline unsigned pagevec_space(struct pagevec *pvec)
{
	return PAGEVEC_SIZE - pvec->nr;
}

/*
 * Add a page to a pagevec.  Returns the number of slots still available.
 */
static inline unsigned pagevec_add(struct pagevec *pvec, struct page *page)
{
	pvec->pages[pvec->nr++] = page;
	return pagevec_space(pvec);
}

static inline void pagevec_release(struct pagevec *pvec)
{
	if (pagevec_count(pvec))
		__pagevec_release(pvec);
}

/**
 * struct folio_batch - A collection of folios.
 *
 * The folio_batch is used to amortise the cost of retrieving and
 * operating on a set of folios.  The order of folios in the batch may be
 * significant (eg delete_from_page_cache_batch()).  Some users of the
 * folio_batch store "exceptional" entries in it which can be removed
 * by calling folio_batch_remove_exceptionals().
 */
struct folio_batch {
	unsigned char nr;
	bool percpu_pvec_drained;
	struct folio *folios[PAGEVEC_SIZE];
};

/* Layout must match pagevec */
static_assert(sizeof(struct pagevec) == sizeof(struct folio_batch));
static_assert(offsetof(struct pagevec, pages) ==
		offsetof(struct folio_batch, folios));

/**
 * folio_batch_init() - Initialise a batch of folios
 * @fbatch: The folio batch.
 *
 * A freshly initialised folio_batch contains zero folios.
 */
static inline void folio_batch_init(struct folio_batch *fbatch)
{
	fbatch->nr = 0;
	fbatch->percpu_pvec_drained = false;
}

static inline void folio_batch_reinit(struct folio_batch *fbatch)
{
	fbatch->nr = 0;
}

static inline unsigned int folio_batch_count(struct folio_batch *fbatch)
{
	return fbatch->nr;
}

static inline unsigned int fbatch_space(struct folio_batch *fbatch)
{
	return PAGEVEC_SIZE - fbatch->nr;
}

/**
 * folio_batch_add() - Add a folio to a batch.
 * @fbatch: The folio batch.
 * @folio: The folio to add.
 *
 * The folio is added to the end of the batch.
 * The batch must have previously been initialised using folio_batch_init().
 *
 * Return: The number of slots still available.
 */
static inline unsigned folio_batch_add(struct folio_batch *fbatch,
		struct folio *folio)
{
	fbatch->folios[fbatch->nr++] = folio;
	return fbatch_space(fbatch);
}

static inline void folio_batch_release(struct folio_batch *fbatch)
{
	pagevec_release((struct pagevec *)fbatch);
}

void folio_batch_remove_exceptionals(struct folio_batch *fbatch);
#endif /* _LINUX_PAGEVEC_H */
Commit	Line	Data
b2441318	1	/* SPDX-License-Identifier: GPL-2.0 */
1da177e4 LT	2	/*
	3	* include/linux/pagevec.h
	4	*
	5	* In many places it is efficient to batch an operation up against multiple
	6	* pages. A pagevec is a multipage container which is used for that.
	7	*/
	8
78854014 DH	9	#ifndef _LINUX_PAGEVEC_H
	10	#define _LINUX_PAGEVEC_H
	11
10bbd235 MW	12	#include <linux/xarray.h>
10bbd235 MW	13
146500e9 MW	14	/* 15 pointers + header align the pagevec structure to a power of two */
146500e9 MW	15	#define PAGEVEC_SIZE 15
1da177e4 LT	16
1da177e4 LT	17	struct page;
10331795	18	struct folio;
1da177e4 LT	19	struct address_space;
1da177e4 LT	20
10331795	21	/* Layout must match folio_batch */
1da177e4	22	struct pagevec {
146500e9	23	unsigned char nr;
7f0b5fb9	24	bool percpu_pvec_drained;
1da177e4 LT	25	struct page *pages[PAGEVEC_SIZE];
	26	};
	27
	28	void __pagevec_release(struct pagevec *pvec);
1da177e4	29
86679820	30	static inline void pagevec_init(struct pagevec *pvec)
1da177e4 LT	31	{
1da177e4 LT	32	pvec->nr = 0;
7f0b5fb9	33	pvec->percpu_pvec_drained = false;
1da177e4 LT	34	}
	35
	36	static inline void pagevec_reinit(struct pagevec *pvec)
	37	{
	38	pvec->nr = 0;
	39	}
	40
	41	static inline unsigned pagevec_count(struct pagevec *pvec)
	42	{
	43	return pvec->nr;
	44	}
	45
	46	static inline unsigned pagevec_space(struct pagevec *pvec)
	47	{
	48	return PAGEVEC_SIZE - pvec->nr;
	49	}
	50
	51	/*
	52	* Add a page to a pagevec. Returns the number of slots still available.
	53	*/
	54	static inline unsigned pagevec_add(struct pagevec pvec, struct page page)
	55	{
	56	pvec->pages[pvec->nr++] = page;
	57	return pagevec_space(pvec);
	58	}
	59
1da177e4 LT	60	static inline void pagevec_release(struct pagevec *pvec)
	61	{
	62	if (pagevec_count(pvec))
	63	__pagevec_release(pvec);
	64	}
	65
10331795 MWO	66	/**
	67	* struct folio_batch - A collection of folios.
	68	*
	69	* The folio_batch is used to amortise the cost of retrieving and
	70	* operating on a set of folios. The order of folios in the batch may be
	71	* significant (eg delete_from_page_cache_batch()). Some users of the
	72	* folio_batch store "exceptional" entries in it which can be removed
	73	* by calling folio_batch_remove_exceptionals().
	74	*/
	75	struct folio_batch {
	76	unsigned char nr;
	77	bool percpu_pvec_drained;
	78	struct folio *folios[PAGEVEC_SIZE];
	79	};
	80
	81	/* Layout must match pagevec */
	82	static_assert(sizeof(struct pagevec) == sizeof(struct folio_batch));
	83	static_assert(offsetof(struct pagevec, pages) ==
	84	offsetof(struct folio_batch, folios));
	85
	86	/**
	87	* folio_batch_init() - Initialise a batch of folios
	88	* @fbatch: The folio batch.
	89	*
	90	* A freshly initialised folio_batch contains zero folios.
	91	*/
	92	static inline void folio_batch_init(struct folio_batch *fbatch)
	93	{
	94	fbatch->nr = 0;
6840f909	95	fbatch->percpu_pvec_drained = false;
10331795 MWO	96	}
10331795 MWO	97
81156128 LS	98	static inline void folio_batch_reinit(struct folio_batch *fbatch)
	99	{
	100	fbatch->nr = 0;
	101	}
	102
10331795 MWO	103	static inline unsigned int folio_batch_count(struct folio_batch *fbatch)
	104	{
	105	return fbatch->nr;
	106	}
	107
	108	static inline unsigned int fbatch_space(struct folio_batch *fbatch)
	109	{
	110	return PAGEVEC_SIZE - fbatch->nr;
	111	}
	112
	113	/**
	114	* folio_batch_add() - Add a folio to a batch.
	115	* @fbatch: The folio batch.
	116	* @folio: The folio to add.
	117	*
	118	* The folio is added to the end of the batch.
	119	* The batch must have previously been initialised using folio_batch_init().
	120	*
	121	* Return: The number of slots still available.
	122	*/
	123	static inline unsigned folio_batch_add(struct folio_batch *fbatch,
	124	struct folio *folio)
	125	{
	126	fbatch->folios[fbatch->nr++] = folio;
	127	return fbatch_space(fbatch);
	128	}
	129
	130	static inline void folio_batch_release(struct folio_batch *fbatch)
	131	{
	132	pagevec_release((struct pagevec *)fbatch);
	133	}
	134
1613fac9	135	void folio_batch_remove_exceptionals(struct folio_batch *fbatch);
78854014	136	#endif /* _LINUX_PAGEVEC_H */