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1/* SPDX-License-Identifier: GPL-2.0-or-later */
2/* Queue of folios definitions
3 *
4 * Copyright (C) 2024 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
6 */
7
8#ifndef _LINUX_FOLIO_QUEUE_H
9#define _LINUX_FOLIO_QUEUE_H
10
11#include <linux/pagevec.h>
12
13/*
14 * Segment in a queue of running buffers. Each segment can hold a number of
15 * folios and a portion of the queue can be referenced with the ITER_FOLIOQ
16 * iterator. The possibility exists of inserting non-folio elements into the
17 * queue (such as gaps).
18 *
19 * Explicit prev and next pointers are used instead of a list_head to make it
20 * easier to add segments to tail and remove them from the head without the
21 * need for a lock.
22 */
23struct folio_queue {
24 struct folio_batch vec; /* Folios in the queue segment */
25 u8 orders[PAGEVEC_SIZE]; /* Order of each folio */
26 struct folio_queue *next; /* Next queue segment or NULL */
27 struct folio_queue *prev; /* Previous queue segment of NULL */
28 unsigned long marks; /* 1-bit mark per folio */
29 unsigned long marks2; /* Second 1-bit mark per folio */
30 unsigned long marks3; /* Third 1-bit mark per folio */
31#if PAGEVEC_SIZE > BITS_PER_LONG
32#error marks is not big enough
33#endif
34};
35
36static inline void folioq_init(struct folio_queue *folioq)
37{
38 folio_batch_init(&folioq->vec);
39 folioq->next = NULL;
40 folioq->prev = NULL;
41 folioq->marks = 0;
42 folioq->marks2 = 0;
43 folioq->marks3 = 0;
44}
45
46static inline unsigned int folioq_nr_slots(const struct folio_queue *folioq)
47{
48 return PAGEVEC_SIZE;
49}
50
51static inline unsigned int folioq_count(struct folio_queue *folioq)
52{
53 return folio_batch_count(&folioq->vec);
54}
55
56static inline bool folioq_full(struct folio_queue *folioq)
57{
58 //return !folio_batch_space(&folioq->vec);
59 return folioq_count(folioq) >= folioq_nr_slots(folioq);
60}
61
62static inline bool folioq_is_marked(const struct folio_queue *folioq, unsigned int slot)
63{
64 return test_bit(slot, &folioq->marks);
65}
66
67static inline void folioq_mark(struct folio_queue *folioq, unsigned int slot)
68{
69 set_bit(slot, &folioq->marks);
70}
71
72static inline void folioq_unmark(struct folio_queue *folioq, unsigned int slot)
73{
74 clear_bit(slot, &folioq->marks);
75}
76
77static inline bool folioq_is_marked2(const struct folio_queue *folioq, unsigned int slot)
78{
79 return test_bit(slot, &folioq->marks2);
80}
81
82static inline void folioq_mark2(struct folio_queue *folioq, unsigned int slot)
83{
84 set_bit(slot, &folioq->marks2);
85}
86
87static inline void folioq_unmark2(struct folio_queue *folioq, unsigned int slot)
88{
89 clear_bit(slot, &folioq->marks2);
90}
91
92static inline bool folioq_is_marked3(const struct folio_queue *folioq, unsigned int slot)
93{
94 return test_bit(slot, &folioq->marks3);
95}
96
97static inline void folioq_mark3(struct folio_queue *folioq, unsigned int slot)
98{
99 set_bit(slot, &folioq->marks3);
100}
101
102static inline void folioq_unmark3(struct folio_queue *folioq, unsigned int slot)
103{
104 clear_bit(slot, &folioq->marks3);
105}
106
107static inline unsigned int __folio_order(struct folio *folio)
108{
109 if (!folio_test_large(folio))
110 return 0;
111 return folio->_flags_1 & 0xff;
112}
113
114static inline unsigned int folioq_append(struct folio_queue *folioq, struct folio *folio)
115{
116 unsigned int slot = folioq->vec.nr++;
117
118 folioq->vec.folios[slot] = folio;
119 folioq->orders[slot] = __folio_order(folio);
120 return slot;
121}
122
123static inline unsigned int folioq_append_mark(struct folio_queue *folioq, struct folio *folio)
124{
125 unsigned int slot = folioq->vec.nr++;
126
127 folioq->vec.folios[slot] = folio;
128 folioq->orders[slot] = __folio_order(folio);
129 folioq_mark(folioq, slot);
130 return slot;
131}
132
133static inline struct folio *folioq_folio(const struct folio_queue *folioq, unsigned int slot)
134{
135 return folioq->vec.folios[slot];
136}
137
138static inline unsigned int folioq_folio_order(const struct folio_queue *folioq, unsigned int slot)
139{
140 return folioq->orders[slot];
141}
142
143static inline size_t folioq_folio_size(const struct folio_queue *folioq, unsigned int slot)
144{
145 return PAGE_SIZE << folioq_folio_order(folioq, slot);
146}
147
148static inline void folioq_clear(struct folio_queue *folioq, unsigned int slot)
149{
150 folioq->vec.folios[slot] = NULL;
151 folioq_unmark(folioq, slot);
152 folioq_unmark2(folioq, slot);
153 folioq_unmark3(folioq, slot);
154}
155
156#endif /* _LINUX_FOLIO_QUEUE_H */