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Diffstat (limited to 'include/linux/pagevec.h')
-rw-r--r-- | include/linux/pagevec.h | 139 |
1 files changed, 139 insertions, 0 deletions
diff --git a/include/linux/pagevec.h b/include/linux/pagevec.h new file mode 100644 index 000000000..215eb6c3b --- /dev/null +++ b/include/linux/pagevec.h @@ -0,0 +1,139 @@ +/* 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); +unsigned pagevec_lookup_range_tag(struct pagevec *pvec, + struct address_space *mapping, pgoff_t *index, pgoff_t end, + xa_mark_t tag); +static inline unsigned pagevec_lookup_tag(struct pagevec *pvec, + struct address_space *mapping, pgoff_t *index, xa_mark_t tag) +{ + return pagevec_lookup_range_tag(pvec, mapping, index, (pgoff_t)-1, tag); +} + +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 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 */ |