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(struct pagevec *pvec,
31 struct address_space *mapping,
32 pgoff_t *start, pgoff_t end);
pagevec_lookup(struct pagevec * pvec,struct address_space * mapping,pgoff_t * start)33 static inline unsigned pagevec_lookup(struct pagevec *pvec,
34 struct address_space *mapping,
35 pgoff_t *start)
36 {
37 return pagevec_lookup_range(pvec, mapping, start, (pgoff_t)-1);
38 }
39
40 unsigned pagevec_lookup_range_tag(struct pagevec *pvec,
41 struct address_space *mapping, pgoff_t *index, pgoff_t end,
42 xa_mark_t tag);
pagevec_lookup_tag(struct pagevec * pvec,struct address_space * mapping,pgoff_t * index,xa_mark_t tag)43 static inline unsigned pagevec_lookup_tag(struct pagevec *pvec,
44 struct address_space *mapping, pgoff_t *index, xa_mark_t tag)
45 {
46 return pagevec_lookup_range_tag(pvec, mapping, index, (pgoff_t)-1, tag);
47 }
48
pagevec_init(struct pagevec * pvec)49 static inline void pagevec_init(struct pagevec *pvec)
50 {
51 pvec->nr = 0;
52 pvec->percpu_pvec_drained = false;
53 }
54
pagevec_reinit(struct pagevec * pvec)55 static inline void pagevec_reinit(struct pagevec *pvec)
56 {
57 pvec->nr = 0;
58 }
59
pagevec_count(struct pagevec * pvec)60 static inline unsigned pagevec_count(struct pagevec *pvec)
61 {
62 return pvec->nr;
63 }
64
pagevec_space(struct pagevec * pvec)65 static inline unsigned pagevec_space(struct pagevec *pvec)
66 {
67 return PAGEVEC_SIZE - pvec->nr;
68 }
69
70 /*
71 * Add a page to a pagevec. Returns the number of slots still available.
72 */
pagevec_add(struct pagevec * pvec,struct page * page)73 static inline unsigned pagevec_add(struct pagevec *pvec, struct page *page)
74 {
75 pvec->pages[pvec->nr++] = page;
76 return pagevec_space(pvec);
77 }
78
pagevec_release(struct pagevec * pvec)79 static inline void pagevec_release(struct pagevec *pvec)
80 {
81 if (pagevec_count(pvec))
82 __pagevec_release(pvec);
83 }
84
85 /**
86 * struct folio_batch - A collection of folios.
87 *
88 * The folio_batch is used to amortise the cost of retrieving and
89 * operating on a set of folios. The order of folios in the batch may be
90 * significant (eg delete_from_page_cache_batch()). Some users of the
91 * folio_batch store "exceptional" entries in it which can be removed
92 * by calling folio_batch_remove_exceptionals().
93 */
94 struct folio_batch {
95 unsigned char nr;
96 bool percpu_pvec_drained;
97 struct folio *folios[PAGEVEC_SIZE];
98 };
99
100 /* Layout must match pagevec */
101 static_assert(sizeof(struct pagevec) == sizeof(struct folio_batch));
102 static_assert(offsetof(struct pagevec, pages) ==
103 offsetof(struct folio_batch, folios));
104
105 /**
106 * folio_batch_init() - Initialise a batch of folios
107 * @fbatch: The folio batch.
108 *
109 * A freshly initialised folio_batch contains zero folios.
110 */
folio_batch_init(struct folio_batch * fbatch)111 static inline void folio_batch_init(struct folio_batch *fbatch)
112 {
113 fbatch->nr = 0;
114 fbatch->percpu_pvec_drained = false;
115 }
116
folio_batch_count(struct folio_batch * fbatch)117 static inline unsigned int folio_batch_count(struct folio_batch *fbatch)
118 {
119 return fbatch->nr;
120 }
121
fbatch_space(struct folio_batch * fbatch)122 static inline unsigned int fbatch_space(struct folio_batch *fbatch)
123 {
124 return PAGEVEC_SIZE - fbatch->nr;
125 }
126
127 /**
128 * folio_batch_add() - Add a folio to a batch.
129 * @fbatch: The folio batch.
130 * @folio: The folio to add.
131 *
132 * The folio is added to the end of the batch.
133 * The batch must have previously been initialised using folio_batch_init().
134 *
135 * Return: The number of slots still available.
136 */
folio_batch_add(struct folio_batch * fbatch,struct folio * folio)137 static inline unsigned folio_batch_add(struct folio_batch *fbatch,
138 struct folio *folio)
139 {
140 fbatch->folios[fbatch->nr++] = folio;
141 return fbatch_space(fbatch);
142 }
143
folio_batch_release(struct folio_batch * fbatch)144 static inline void folio_batch_release(struct folio_batch *fbatch)
145 {
146 pagevec_release((struct pagevec *)fbatch);
147 }
148
149 void folio_batch_remove_exceptionals(struct folio_batch *fbatch);
150 #endif /* _LINUX_PAGEVEC_H */
151