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/* 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 folio_batch_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 folio_batch_space(fbatch);
}
static inline void __folio_batch_release(struct folio_batch *fbatch)
{
__pagevec_release((struct pagevec *)fbatch);
}
static inline void folio_batch_release(struct folio_batch *fbatch)
{
if (folio_batch_count(fbatch))
__folio_batch_release(fbatch);
}
void folio_batch_remove_exceptionals(struct folio_batch *fbatch);
#endif /* _LINUX_PAGEVEC_H */
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