1 /* SPDX-License-Identifier: GPL-2.0 */ 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 9 #ifndef _LINUX_PAGEVEC_H 10 #define _LINUX_PAGEVEC_H 11 12 #include <linux/xarray.h> 13 14 /* 15 pointers + header align the pagevec structure to a power of two */ 15 #define PAGEVEC_SIZE 15 16 17 struct page; 18 struct folio; 19 struct address_space; 20 21 /* Layout must match folio_batch */ 22 struct pagevec { 23 unsigned char nr; 24 bool percpu_pvec_drained; 25 struct page *pages[PAGEVEC_SIZE]; 26 }; 27 28 void __pagevec_release(struct pagevec *pvec); 29 void __pagevec_lru_add(struct pagevec *pvec); 30 unsigned pagevec_lookup_range_tag(struct pagevec *pvec, 31 struct address_space *mapping, pgoff_t *index, pgoff_t end, 32 xa_mark_t tag); 33 static inline unsigned pagevec_lookup_tag(struct pagevec *pvec, 34 struct address_space *mapping, pgoff_t *index, xa_mark_t tag) 35 { 36 return pagevec_lookup_range_tag(pvec, mapping, index, (pgoff_t)-1, tag); 37 } 38 39 static inline void pagevec_init(struct pagevec *pvec) 40 { 41 pvec->nr = 0; 42 pvec->percpu_pvec_drained = false; 43 } 44 45 static inline void pagevec_reinit(struct pagevec *pvec) 46 { 47 pvec->nr = 0; 48 } 49 50 static inline unsigned pagevec_count(struct pagevec *pvec) 51 { 52 return pvec->nr; 53 } 54 55 static inline unsigned pagevec_space(struct pagevec *pvec) 56 { 57 return PAGEVEC_SIZE - pvec->nr; 58 } 59 60 /* 61 * Add a page to a pagevec. Returns the number of slots still available. 62 */ 63 static inline unsigned pagevec_add(struct pagevec *pvec, struct page *page) 64 { 65 pvec->pages[pvec->nr++] = page; 66 return pagevec_space(pvec); 67 } 68 69 static inline void pagevec_release(struct pagevec *pvec) 70 { 71 if (pagevec_count(pvec)) 72 __pagevec_release(pvec); 73 } 74 75 /** 76 * struct folio_batch - A collection of folios. 77 * 78 * The folio_batch is used to amortise the cost of retrieving and 79 * operating on a set of folios. The order of folios in the batch may be 80 * significant (eg delete_from_page_cache_batch()). Some users of the 81 * folio_batch store "exceptional" entries in it which can be removed 82 * by calling folio_batch_remove_exceptionals(). 83 */ 84 struct folio_batch { 85 unsigned char nr; 86 bool percpu_pvec_drained; 87 struct folio *folios[PAGEVEC_SIZE]; 88 }; 89 90 /* Layout must match pagevec */ 91 static_assert(sizeof(struct pagevec) == sizeof(struct folio_batch)); 92 static_assert(offsetof(struct pagevec, pages) == 93 offsetof(struct folio_batch, folios)); 94 95 /** 96 * folio_batch_init() - Initialise a batch of folios 97 * @fbatch: The folio batch. 98 * 99 * A freshly initialised folio_batch contains zero folios. 100 */ 101 static inline void folio_batch_init(struct folio_batch *fbatch) 102 { 103 fbatch->nr = 0; 104 fbatch->percpu_pvec_drained = false; 105 } 106 107 static inline unsigned int folio_batch_count(struct folio_batch *fbatch) 108 { 109 return fbatch->nr; 110 } 111 112 static inline unsigned int fbatch_space(struct folio_batch *fbatch) 113 { 114 return PAGEVEC_SIZE - fbatch->nr; 115 } 116 117 /** 118 * folio_batch_add() - Add a folio to a batch. 119 * @fbatch: The folio batch. 120 * @folio: The folio to add. 121 * 122 * The folio is added to the end of the batch. 123 * The batch must have previously been initialised using folio_batch_init(). 124 * 125 * Return: The number of slots still available. 126 */ 127 static inline unsigned folio_batch_add(struct folio_batch *fbatch, 128 struct folio *folio) 129 { 130 fbatch->folios[fbatch->nr++] = folio; 131 return fbatch_space(fbatch); 132 } 133 134 static inline void folio_batch_release(struct folio_batch *fbatch) 135 { 136 pagevec_release((struct pagevec *)fbatch); 137 } 138 139 void folio_batch_remove_exceptionals(struct folio_batch *fbatch); 140 #endif /* _LINUX_PAGEVEC_H */ 141