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