Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * Copyright (C) 2018 HUAWEI, Inc.
4 * https://www.huawei.com/
5 */
6#ifndef __EROFS_FS_ZDATA_H
7#define __EROFS_FS_ZDATA_H
8
9#include "internal.h"
10#include "tagptr.h"
11
12#define Z_EROFS_PCLUSTER_MAX_PAGES (Z_EROFS_PCLUSTER_MAX_SIZE / PAGE_SIZE)
13#define Z_EROFS_INLINE_BVECS 2
14
15/*
16 * let's leave a type here in case of introducing
17 * another tagged pointer later.
18 */
19typedef void *z_erofs_next_pcluster_t;
20
21struct z_erofs_bvec {
22 struct page *page;
23 int offset;
24 unsigned int end;
25};
26
27#define __Z_EROFS_BVSET(name, total) \
28struct name { \
29 /* point to the next page which contains the following bvecs */ \
30 struct page *nextpage; \
31 struct z_erofs_bvec bvec[total]; \
32}
33__Z_EROFS_BVSET(z_erofs_bvset,);
34__Z_EROFS_BVSET(z_erofs_bvset_inline, Z_EROFS_INLINE_BVECS);
35
36/*
37 * Structure fields follow one of the following exclusion rules.
38 *
39 * I: Modifiable by initialization/destruction paths and read-only
40 * for everyone else;
41 *
42 * L: Field should be protected by the pcluster lock;
43 *
44 * A: Field should be accessed / updated in atomic for parallelized code.
45 */
46struct z_erofs_pcluster {
47 struct erofs_workgroup obj;
48 struct mutex lock;
49
50 /* A: point to next chained pcluster or TAILs */
51 z_erofs_next_pcluster_t next;
52
53 /* L: the maximum decompression size of this round */
54 unsigned int length;
55
56 /* L: total number of bvecs */
57 unsigned int vcnt;
58
59 /* I: page offset of start position of decompression */
60 unsigned short pageofs_out;
61
62 /* I: page offset of inline compressed data */
63 unsigned short pageofs_in;
64
65 union {
66 /* L: inline a certain number of bvec for bootstrap */
67 struct z_erofs_bvset_inline bvset;
68
69 /* I: can be used to free the pcluster by RCU. */
70 struct rcu_head rcu;
71 };
72
73 union {
74 /* I: physical cluster size in pages */
75 unsigned short pclusterpages;
76
77 /* I: tailpacking inline compressed size */
78 unsigned short tailpacking_size;
79 };
80
81 /* I: compression algorithm format */
82 unsigned char algorithmformat;
83
84 /* L: whether partial decompression or not */
85 bool partial;
86
87 /* L: indicate several pageofs_outs or not */
88 bool multibases;
89
90 /* A: compressed bvecs (can be cached or inplaced pages) */
91 struct z_erofs_bvec compressed_bvecs[];
92};
93
94/* let's avoid the valid 32-bit kernel addresses */
95
96/* the chained workgroup has't submitted io (still open) */
97#define Z_EROFS_PCLUSTER_TAIL ((void *)0x5F0ECAFE)
98/* the chained workgroup has already submitted io */
99#define Z_EROFS_PCLUSTER_TAIL_CLOSED ((void *)0x5F0EDEAD)
100
101#define Z_EROFS_PCLUSTER_NIL (NULL)
102
103struct z_erofs_decompressqueue {
104 struct super_block *sb;
105 atomic_t pending_bios;
106 z_erofs_next_pcluster_t head;
107
108 union {
109 struct completion done;
110 struct work_struct work;
111 } u;
112
113 bool eio;
114};
115
116static inline bool z_erofs_is_inline_pcluster(struct z_erofs_pcluster *pcl)
117{
118 return !pcl->obj.index;
119}
120
121static inline unsigned int z_erofs_pclusterpages(struct z_erofs_pcluster *pcl)
122{
123 if (z_erofs_is_inline_pcluster(pcl))
124 return 1;
125 return pcl->pclusterpages;
126}
127
128/*
129 * bit 31: I/O error occurred on this page
130 * bit 0 - 30: remaining parts to complete this page
131 */
132#define Z_EROFS_PAGE_EIO (1 << 31)
133
134static inline void z_erofs_onlinepage_init(struct page *page)
135{
136 union {
137 atomic_t o;
138 unsigned long v;
139 } u = { .o = ATOMIC_INIT(1) };
140
141 set_page_private(page, u.v);
142 smp_wmb();
143 SetPagePrivate(page);
144}
145
146static inline void z_erofs_onlinepage_split(struct page *page)
147{
148 atomic_inc((atomic_t *)&page->private);
149}
150
151static inline void z_erofs_page_mark_eio(struct page *page)
152{
153 int orig;
154
155 do {
156 orig = atomic_read((atomic_t *)&page->private);
157 } while (atomic_cmpxchg((atomic_t *)&page->private, orig,
158 orig | Z_EROFS_PAGE_EIO) != orig);
159}
160
161static inline void z_erofs_onlinepage_endio(struct page *page)
162{
163 unsigned int v;
164
165 DBG_BUGON(!PagePrivate(page));
166 v = atomic_dec_return((atomic_t *)&page->private);
167 if (!(v & ~Z_EROFS_PAGE_EIO)) {
168 set_page_private(page, 0);
169 ClearPagePrivate(page);
170 if (!(v & Z_EROFS_PAGE_EIO))
171 SetPageUptodate(page);
172 unlock_page(page);
173 }
174}
175
176#define Z_EROFS_ONSTACK_PAGES 32
177
178#endif