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 "zpvec.h"
11
12 #define Z_EROFS_PCLUSTER_MAX_PAGES (Z_EROFS_PCLUSTER_MAX_SIZE / PAGE_SIZE)
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 */
25 struct 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 */
53 typedef void *z_erofs_next_pcluster_t;
54
55 struct 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: lower limit of decompressed length and if full length or not */
63 unsigned int length;
64
65 /* I: physical cluster size in pages */
66 unsigned short pclusterpages;
67
68 /* I: compression algorithm format */
69 unsigned char algorithmformat;
70
71 /* A: compressed pages (can be cached or inplaced pages) */
72 struct page *compressed_pages[];
73 };
74
75 #define z_erofs_primarycollection(pcluster) (&(pcluster)->primary_collection)
76
77 /* let's avoid the valid 32-bit kernel addresses */
78
79 /* the chained workgroup has't submitted io (still open) */
80 #define Z_EROFS_PCLUSTER_TAIL ((void *)0x5F0ECAFE)
81 /* the chained workgroup has already submitted io */
82 #define Z_EROFS_PCLUSTER_TAIL_CLOSED ((void *)0x5F0EDEAD)
83
84 #define Z_EROFS_PCLUSTER_NIL (NULL)
85
86 struct z_erofs_decompressqueue {
87 struct super_block *sb;
88 atomic_t pending_bios;
89 z_erofs_next_pcluster_t head;
90
91 union {
92 wait_queue_head_t wait;
93 struct work_struct work;
94 } u;
95 };
96
97 #define MNGD_MAPPING(sbi) ((sbi)->managed_cache->i_mapping)
erofs_page_is_managed(const struct erofs_sb_info * sbi,struct page * page)98 static inline bool erofs_page_is_managed(const struct erofs_sb_info *sbi,
99 struct page *page)
100 {
101 return page->mapping == MNGD_MAPPING(sbi);
102 }
103
104 #define Z_EROFS_ONLINEPAGE_COUNT_BITS 2
105 #define Z_EROFS_ONLINEPAGE_COUNT_MASK ((1 << Z_EROFS_ONLINEPAGE_COUNT_BITS) - 1)
106 #define Z_EROFS_ONLINEPAGE_INDEX_SHIFT (Z_EROFS_ONLINEPAGE_COUNT_BITS)
107
108 /*
109 * waiters (aka. ongoing_packs): # to unlock the page
110 * sub-index: 0 - for partial page, >= 1 full page sub-index
111 */
112 typedef atomic_t z_erofs_onlinepage_t;
113
114 /* type punning */
115 union z_erofs_onlinepage_converter {
116 z_erofs_onlinepage_t *o;
117 unsigned long *v;
118 };
119
z_erofs_onlinepage_index(struct page * page)120 static inline unsigned int z_erofs_onlinepage_index(struct page *page)
121 {
122 union z_erofs_onlinepage_converter u;
123
124 DBG_BUGON(!PagePrivate(page));
125 u.v = &page_private(page);
126
127 return atomic_read(u.o) >> Z_EROFS_ONLINEPAGE_INDEX_SHIFT;
128 }
129
z_erofs_onlinepage_init(struct page * page)130 static inline void z_erofs_onlinepage_init(struct page *page)
131 {
132 union {
133 z_erofs_onlinepage_t o;
134 unsigned long v;
135 /* keep from being unlocked in advance */
136 } u = { .o = ATOMIC_INIT(1) };
137
138 set_page_private(page, u.v);
139 smp_wmb();
140 SetPagePrivate(page);
141 }
142
z_erofs_onlinepage_fixup(struct page * page,uintptr_t index,bool down)143 static inline void z_erofs_onlinepage_fixup(struct page *page,
144 uintptr_t index, bool down)
145 {
146 union z_erofs_onlinepage_converter u = { .v = &page_private(page) };
147 int orig, orig_index, val;
148
149 repeat:
150 orig = atomic_read(u.o);
151 orig_index = orig >> Z_EROFS_ONLINEPAGE_INDEX_SHIFT;
152 if (orig_index) {
153 if (!index)
154 return;
155
156 DBG_BUGON(orig_index != index);
157 }
158
159 val = (index << Z_EROFS_ONLINEPAGE_INDEX_SHIFT) |
160 ((orig & Z_EROFS_ONLINEPAGE_COUNT_MASK) + (unsigned int)down);
161 if (atomic_cmpxchg(u.o, orig, val) != orig)
162 goto repeat;
163 }
164
z_erofs_onlinepage_endio(struct page * page)165 static inline void z_erofs_onlinepage_endio(struct page *page)
166 {
167 union z_erofs_onlinepage_converter u;
168 unsigned int v;
169
170 DBG_BUGON(!PagePrivate(page));
171 u.v = &page_private(page);
172
173 v = atomic_dec_return(u.o);
174 if (!(v & Z_EROFS_ONLINEPAGE_COUNT_MASK)) {
175 set_page_private(page, 0);
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
190
