Linux kernel mirror (for testing)
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1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * Copyright (C) 2018 HUAWEI, Inc.
4 * http://www.huawei.com/
5 * Created by Gao Xiang <gaoxiang25@huawei.com>
6 */
7#ifndef __EROFS_FS_ZDATA_H
8#define __EROFS_FS_ZDATA_H
9
10#include "internal.h"
11#include "zpvec.h"
12
13#define Z_EROFS_NR_INLINE_PAGEVECS 3
14
15/*
16 * Structure fields follow one of the following exclusion rules.
17 *
18 * I: Modifiable by initialization/destruction paths and read-only
19 * for everyone else;
20 *
21 * L: Field should be protected by pageset lock;
22 *
23 * A: Field should be accessed / updated in atomic for parallelized code.
24 */
25struct z_erofs_collection {
26 struct mutex lock;
27
28 /* I: page offset of start position of decompression */
29 unsigned short pageofs;
30
31 /* L: maximum relative page index in pagevec[] */
32 unsigned short nr_pages;
33
34 /* L: total number of pages in pagevec[] */
35 unsigned int vcnt;
36
37 union {
38 /* L: inline a certain number of pagevecs for bootstrap */
39 erofs_vtptr_t pagevec[Z_EROFS_NR_INLINE_PAGEVECS];
40
41 /* I: can be used to free the pcluster by RCU. */
42 struct rcu_head rcu;
43 };
44};
45
46#define Z_EROFS_PCLUSTER_FULL_LENGTH 0x00000001
47#define Z_EROFS_PCLUSTER_LENGTH_BIT 1
48
49/*
50 * let's leave a type here in case of introducing
51 * another tagged pointer later.
52 */
53typedef void *z_erofs_next_pcluster_t;
54
55struct z_erofs_pcluster {
56 struct erofs_workgroup obj;
57 struct z_erofs_collection primary_collection;
58
59 /* A: point to next chained pcluster or TAILs */
60 z_erofs_next_pcluster_t next;
61
62 /* A: compressed pages (including multi-usage pages) */
63 struct page *compressed_pages[Z_EROFS_CLUSTER_MAX_PAGES];
64
65 /* A: lower limit of decompressed length and if full length or not */
66 unsigned int length;
67
68 /* I: compression algorithm format */
69 unsigned char algorithmformat;
70 /* I: bit shift of physical cluster size */
71 unsigned char clusterbits;
72};
73
74#define z_erofs_primarycollection(pcluster) (&(pcluster)->primary_collection)
75
76/* let's avoid the valid 32-bit kernel addresses */
77
78/* the chained workgroup has't submitted io (still open) */
79#define Z_EROFS_PCLUSTER_TAIL ((void *)0x5F0ECAFE)
80/* the chained workgroup has already submitted io */
81#define Z_EROFS_PCLUSTER_TAIL_CLOSED ((void *)0x5F0EDEAD)
82
83#define Z_EROFS_PCLUSTER_NIL (NULL)
84
85#define Z_EROFS_WORKGROUP_SIZE sizeof(struct z_erofs_pcluster)
86
87struct z_erofs_decompressqueue {
88 struct super_block *sb;
89 atomic_t pending_bios;
90 z_erofs_next_pcluster_t head;
91
92 union {
93 wait_queue_head_t wait;
94 struct work_struct work;
95 } u;
96};
97
98#define MNGD_MAPPING(sbi) ((sbi)->managed_cache->i_mapping)
99static inline bool erofs_page_is_managed(const struct erofs_sb_info *sbi,
100 struct page *page)
101{
102 return page->mapping == MNGD_MAPPING(sbi);
103}
104
105#define Z_EROFS_ONLINEPAGE_COUNT_BITS 2
106#define Z_EROFS_ONLINEPAGE_COUNT_MASK ((1 << Z_EROFS_ONLINEPAGE_COUNT_BITS) - 1)
107#define Z_EROFS_ONLINEPAGE_INDEX_SHIFT (Z_EROFS_ONLINEPAGE_COUNT_BITS)
108
109/*
110 * waiters (aka. ongoing_packs): # to unlock the page
111 * sub-index: 0 - for partial page, >= 1 full page sub-index
112 */
113typedef atomic_t z_erofs_onlinepage_t;
114
115/* type punning */
116union z_erofs_onlinepage_converter {
117 z_erofs_onlinepage_t *o;
118 unsigned long *v;
119};
120
121static inline unsigned int z_erofs_onlinepage_index(struct page *page)
122{
123 union z_erofs_onlinepage_converter u;
124
125 DBG_BUGON(!PagePrivate(page));
126 u.v = &page_private(page);
127
128 return atomic_read(u.o) >> Z_EROFS_ONLINEPAGE_INDEX_SHIFT;
129}
130
131static inline void z_erofs_onlinepage_init(struct page *page)
132{
133 union {
134 z_erofs_onlinepage_t o;
135 unsigned long v;
136 /* keep from being unlocked in advance */
137 } u = { .o = ATOMIC_INIT(1) };
138
139 set_page_private(page, u.v);
140 smp_wmb();
141 SetPagePrivate(page);
142}
143
144static inline void z_erofs_onlinepage_fixup(struct page *page,
145 uintptr_t index, bool down)
146{
147 union z_erofs_onlinepage_converter u = { .v = &page_private(page) };
148 int orig, orig_index, val;
149
150repeat:
151 orig = atomic_read(u.o);
152 orig_index = orig >> Z_EROFS_ONLINEPAGE_INDEX_SHIFT;
153 if (orig_index) {
154 if (!index)
155 return;
156
157 DBG_BUGON(orig_index != index);
158 }
159
160 val = (index << Z_EROFS_ONLINEPAGE_INDEX_SHIFT) |
161 ((orig & Z_EROFS_ONLINEPAGE_COUNT_MASK) + (unsigned int)down);
162 if (atomic_cmpxchg(u.o, orig, val) != orig)
163 goto repeat;
164}
165
166static inline void z_erofs_onlinepage_endio(struct page *page)
167{
168 union z_erofs_onlinepage_converter u;
169 unsigned int v;
170
171 DBG_BUGON(!PagePrivate(page));
172 u.v = &page_private(page);
173
174 v = atomic_dec_return(u.o);
175 if (!(v & Z_EROFS_ONLINEPAGE_COUNT_MASK)) {
176 ClearPagePrivate(page);
177 if (!PageError(page))
178 SetPageUptodate(page);
179 unlock_page(page);
180 }
181 erofs_dbg("%s, page %p value %x", __func__, page, atomic_read(u.o));
182}
183
184#define Z_EROFS_VMAP_ONSTACK_PAGES \
185 min_t(unsigned int, THREAD_SIZE / 8 / sizeof(struct page *), 96U)
186#define Z_EROFS_VMAP_GLOBAL_PAGES 2048
187
188#endif
189