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1/* SPDX-License-Identifier: GPL-2.0 */2/*3 * include/linux/pagevec.h4 *5 * In many places it is efficient to batch an operation up against multiple6 * folios. A folio_batch is a container which is used for that.7 */8 9#ifndef _LINUX_PAGEVEC_H10#define _LINUX_PAGEVEC_H11 12#include <linux/types.h>13 14/* 31 pointers + header align the folio_batch structure to a power of two */15#define PAGEVEC_SIZE 3116 17struct folio;18 19/**20 * struct folio_batch - A collection of folios.21 *22 * The folio_batch is used to amortise the cost of retrieving and23 * operating on a set of folios. The order of folios in the batch may be24 * significant (eg delete_from_page_cache_batch()). Some users of the25 * folio_batch store "exceptional" entries in it which can be removed26 * by calling folio_batch_remove_exceptionals().27 */28struct folio_batch {29 unsigned char nr;30 unsigned char i;31 bool percpu_pvec_drained;32 struct folio *folios[PAGEVEC_SIZE];33};34 35/**36 * folio_batch_init() - Initialise a batch of folios37 * @fbatch: The folio batch.38 *39 * A freshly initialised folio_batch contains zero folios.40 */41static inline void folio_batch_init(struct folio_batch *fbatch)42{43 fbatch->nr = 0;44 fbatch->i = 0;45 fbatch->percpu_pvec_drained = false;46}47 48static inline void folio_batch_reinit(struct folio_batch *fbatch)49{50 fbatch->nr = 0;51 fbatch->i = 0;52}53 54static inline unsigned int folio_batch_count(struct folio_batch *fbatch)55{56 return fbatch->nr;57}58 59static inline unsigned int folio_batch_space(struct folio_batch *fbatch)60{61 return PAGEVEC_SIZE - fbatch->nr;62}63 64/**65 * folio_batch_add() - Add a folio to a batch.66 * @fbatch: The folio batch.67 * @folio: The folio to add.68 *69 * The folio is added to the end of the batch.70 * The batch must have previously been initialised using folio_batch_init().71 *72 * Return: The number of slots still available.73 */74static inline unsigned folio_batch_add(struct folio_batch *fbatch,75 struct folio *folio)76{77 fbatch->folios[fbatch->nr++] = folio;78 return folio_batch_space(fbatch);79}80 81/**82 * folio_batch_next - Return the next folio to process.83 * @fbatch: The folio batch being processed.84 *85 * Use this function to implement a queue of folios.86 *87 * Return: The next folio in the queue, or NULL if the queue is empty.88 */89static inline struct folio *folio_batch_next(struct folio_batch *fbatch)90{91 if (fbatch->i == fbatch->nr)92 return NULL;93 return fbatch->folios[fbatch->i++];94}95 96void __folio_batch_release(struct folio_batch *pvec);97 98static inline void folio_batch_release(struct folio_batch *fbatch)99{100 if (folio_batch_count(fbatch))101 __folio_batch_release(fbatch);102}103 104void folio_batch_remove_exceptionals(struct folio_batch *fbatch);105#endif /* _LINUX_PAGEVEC_H */106