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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * include/linux/backing-dev.h | |
3 | * | |
4 | * low-level device information and state which is propagated up through | |
5 | * to high-level code. | |
6 | */ | |
7 | ||
8 | #ifndef _LINUX_BACKING_DEV_H | |
9 | #define _LINUX_BACKING_DEV_H | |
10 | ||
cf0ca9fe | 11 | #include <linux/kernel.h> |
e4ad08fe | 12 | #include <linux/fs.h> |
03ba3782 | 13 | #include <linux/sched.h> |
a212b105 | 14 | #include <linux/blkdev.h> |
03ba3782 | 15 | #include <linux/writeback.h> |
66114cad | 16 | #include <linux/backing-dev-defs.h> |
1da177e4 | 17 | |
8077c0d9 | 18 | int __must_check bdi_init(struct backing_dev_info *bdi); |
b2e8fb6e PZ |
19 | void bdi_destroy(struct backing_dev_info *bdi); |
20 | ||
d2cc4dde | 21 | __printf(3, 4) |
cf0ca9fe PZ |
22 | int bdi_register(struct backing_dev_info *bdi, struct device *parent, |
23 | const char *fmt, ...); | |
24 | int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev); | |
25 | void bdi_unregister(struct backing_dev_info *bdi); | |
b4caecd4 | 26 | int __must_check bdi_setup_and_register(struct backing_dev_info *, char *); |
0e175a18 CW |
27 | void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages, |
28 | enum wb_reason reason); | |
c5444198 | 29 | void bdi_start_background_writeback(struct backing_dev_info *bdi); |
f0054bb1 | 30 | void wb_workfn(struct work_struct *work); |
03ba3782 | 31 | int bdi_has_dirty_io(struct backing_dev_info *bdi); |
f0054bb1 | 32 | void wb_wakeup_delayed(struct bdi_writeback *wb); |
cf0ca9fe | 33 | |
03ba3782 | 34 | extern spinlock_t bdi_lock; |
66f3b8e2 JA |
35 | extern struct list_head bdi_list; |
36 | ||
839a8e86 TH |
37 | extern struct workqueue_struct *bdi_wq; |
38 | ||
03ba3782 JA |
39 | static inline int wb_has_dirty_io(struct bdi_writeback *wb) |
40 | { | |
41 | return !list_empty(&wb->b_dirty) || | |
42 | !list_empty(&wb->b_io) || | |
43 | !list_empty(&wb->b_more_io); | |
44 | } | |
45 | ||
93f78d88 TH |
46 | static inline void __add_wb_stat(struct bdi_writeback *wb, |
47 | enum wb_stat_item item, s64 amount) | |
b2e8fb6e | 48 | { |
93f78d88 | 49 | __percpu_counter_add(&wb->stat[item], amount, WB_STAT_BATCH); |
b2e8fb6e PZ |
50 | } |
51 | ||
93f78d88 TH |
52 | static inline void __inc_wb_stat(struct bdi_writeback *wb, |
53 | enum wb_stat_item item) | |
b2e8fb6e | 54 | { |
93f78d88 | 55 | __add_wb_stat(wb, item, 1); |
b2e8fb6e PZ |
56 | } |
57 | ||
93f78d88 | 58 | static inline void inc_wb_stat(struct bdi_writeback *wb, enum wb_stat_item item) |
b2e8fb6e PZ |
59 | { |
60 | unsigned long flags; | |
61 | ||
62 | local_irq_save(flags); | |
93f78d88 | 63 | __inc_wb_stat(wb, item); |
b2e8fb6e PZ |
64 | local_irq_restore(flags); |
65 | } | |
66 | ||
93f78d88 TH |
67 | static inline void __dec_wb_stat(struct bdi_writeback *wb, |
68 | enum wb_stat_item item) | |
b2e8fb6e | 69 | { |
93f78d88 | 70 | __add_wb_stat(wb, item, -1); |
b2e8fb6e PZ |
71 | } |
72 | ||
93f78d88 | 73 | static inline void dec_wb_stat(struct bdi_writeback *wb, enum wb_stat_item item) |
b2e8fb6e PZ |
74 | { |
75 | unsigned long flags; | |
76 | ||
77 | local_irq_save(flags); | |
93f78d88 | 78 | __dec_wb_stat(wb, item); |
b2e8fb6e PZ |
79 | local_irq_restore(flags); |
80 | } | |
81 | ||
93f78d88 | 82 | static inline s64 wb_stat(struct bdi_writeback *wb, enum wb_stat_item item) |
b2e8fb6e | 83 | { |
93f78d88 | 84 | return percpu_counter_read_positive(&wb->stat[item]); |
b2e8fb6e PZ |
85 | } |
86 | ||
93f78d88 TH |
87 | static inline s64 __wb_stat_sum(struct bdi_writeback *wb, |
88 | enum wb_stat_item item) | |
b2e8fb6e | 89 | { |
93f78d88 | 90 | return percpu_counter_sum_positive(&wb->stat[item]); |
b2e8fb6e PZ |
91 | } |
92 | ||
93f78d88 | 93 | static inline s64 wb_stat_sum(struct bdi_writeback *wb, enum wb_stat_item item) |
e0bf68dd | 94 | { |
b2e8fb6e PZ |
95 | s64 sum; |
96 | unsigned long flags; | |
97 | ||
98 | local_irq_save(flags); | |
93f78d88 | 99 | sum = __wb_stat_sum(wb, item); |
b2e8fb6e PZ |
100 | local_irq_restore(flags); |
101 | ||
102 | return sum; | |
e0bf68dd PZ |
103 | } |
104 | ||
93f78d88 | 105 | extern void wb_writeout_inc(struct bdi_writeback *wb); |
dd5656e5 | 106 | |
b2e8fb6e PZ |
107 | /* |
108 | * maximal error of a stat counter. | |
109 | */ | |
93f78d88 | 110 | static inline unsigned long wb_stat_error(struct bdi_writeback *wb) |
e0bf68dd | 111 | { |
b2e8fb6e | 112 | #ifdef CONFIG_SMP |
93f78d88 | 113 | return nr_cpu_ids * WB_STAT_BATCH; |
b2e8fb6e PZ |
114 | #else |
115 | return 1; | |
116 | #endif | |
e0bf68dd | 117 | } |
1da177e4 | 118 | |
189d3c4a | 119 | int bdi_set_min_ratio(struct backing_dev_info *bdi, unsigned int min_ratio); |
a42dde04 | 120 | int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ratio); |
189d3c4a | 121 | |
1da177e4 LT |
122 | /* |
123 | * Flags in backing_dev_info::capability | |
e4ad08fe MS |
124 | * |
125 | * The first three flags control whether dirty pages will contribute to the | |
126 | * VM's accounting and whether writepages() should be called for dirty pages | |
127 | * (something that would not, for example, be appropriate for ramfs) | |
128 | * | |
129 | * WARNING: these flags are closely related and should not normally be | |
130 | * used separately. The BDI_CAP_NO_ACCT_AND_WRITEBACK combines these | |
131 | * three flags into a single convenience macro. | |
132 | * | |
133 | * BDI_CAP_NO_ACCT_DIRTY: Dirty pages shouldn't contribute to accounting | |
134 | * BDI_CAP_NO_WRITEBACK: Don't write pages back | |
135 | * BDI_CAP_NO_ACCT_WB: Don't automatically account writeback pages | |
5a537485 | 136 | * BDI_CAP_STRICTLIMIT: Keep number of dirty pages below bdi threshold. |
89e9b9e0 TH |
137 | * |
138 | * BDI_CAP_CGROUP_WRITEBACK: Supports cgroup-aware writeback. | |
1da177e4 | 139 | */ |
e4ad08fe MS |
140 | #define BDI_CAP_NO_ACCT_DIRTY 0x00000001 |
141 | #define BDI_CAP_NO_WRITEBACK 0x00000002 | |
b4caecd4 CH |
142 | #define BDI_CAP_NO_ACCT_WB 0x00000004 |
143 | #define BDI_CAP_STABLE_WRITES 0x00000008 | |
144 | #define BDI_CAP_STRICTLIMIT 0x00000010 | |
89e9b9e0 | 145 | #define BDI_CAP_CGROUP_WRITEBACK 0x00000020 |
1da177e4 | 146 | |
e4ad08fe MS |
147 | #define BDI_CAP_NO_ACCT_AND_WRITEBACK \ |
148 | (BDI_CAP_NO_WRITEBACK | BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_ACCT_WB) | |
149 | ||
5129a469 | 150 | extern struct backing_dev_info noop_backing_dev_info; |
1da177e4 | 151 | |
1da177e4 | 152 | int writeback_in_progress(struct backing_dev_info *bdi); |
1da177e4 | 153 | |
a212b105 TH |
154 | static inline struct backing_dev_info *inode_to_bdi(struct inode *inode) |
155 | { | |
156 | struct super_block *sb; | |
157 | ||
158 | if (!inode) | |
159 | return &noop_backing_dev_info; | |
160 | ||
161 | sb = inode->i_sb; | |
162 | #ifdef CONFIG_BLOCK | |
163 | if (sb_is_blkdev_sb(sb)) | |
164 | return blk_get_backing_dev_info(I_BDEV(inode)); | |
165 | #endif | |
166 | return sb->s_bdi; | |
167 | } | |
168 | ||
1da177e4 LT |
169 | static inline int bdi_congested(struct backing_dev_info *bdi, int bdi_bits) |
170 | { | |
171 | if (bdi->congested_fn) | |
172 | return bdi->congested_fn(bdi->congested_data, bdi_bits); | |
4aa9c692 | 173 | return (bdi->wb.congested->state & bdi_bits); |
1da177e4 LT |
174 | } |
175 | ||
176 | static inline int bdi_read_congested(struct backing_dev_info *bdi) | |
177 | { | |
4452226e | 178 | return bdi_congested(bdi, 1 << WB_sync_congested); |
1da177e4 LT |
179 | } |
180 | ||
181 | static inline int bdi_write_congested(struct backing_dev_info *bdi) | |
182 | { | |
4452226e | 183 | return bdi_congested(bdi, 1 << WB_async_congested); |
1da177e4 LT |
184 | } |
185 | ||
186 | static inline int bdi_rw_congested(struct backing_dev_info *bdi) | |
187 | { | |
4452226e TH |
188 | return bdi_congested(bdi, (1 << WB_sync_congested) | |
189 | (1 << WB_async_congested)); | |
1da177e4 LT |
190 | } |
191 | ||
8aa7e847 | 192 | long congestion_wait(int sync, long timeout); |
0e093d99 | 193 | long wait_iff_congested(struct zone *zone, int sync, long timeout); |
3965c9ae WL |
194 | int pdflush_proc_obsolete(struct ctl_table *table, int write, |
195 | void __user *buffer, size_t *lenp, loff_t *ppos); | |
1da177e4 | 196 | |
7d311cda DW |
197 | static inline bool bdi_cap_stable_pages_required(struct backing_dev_info *bdi) |
198 | { | |
199 | return bdi->capabilities & BDI_CAP_STABLE_WRITES; | |
200 | } | |
201 | ||
e4ad08fe MS |
202 | static inline bool bdi_cap_writeback_dirty(struct backing_dev_info *bdi) |
203 | { | |
204 | return !(bdi->capabilities & BDI_CAP_NO_WRITEBACK); | |
205 | } | |
206 | ||
207 | static inline bool bdi_cap_account_dirty(struct backing_dev_info *bdi) | |
208 | { | |
209 | return !(bdi->capabilities & BDI_CAP_NO_ACCT_DIRTY); | |
210 | } | |
1da177e4 | 211 | |
e4ad08fe MS |
212 | static inline bool bdi_cap_account_writeback(struct backing_dev_info *bdi) |
213 | { | |
214 | /* Paranoia: BDI_CAP_NO_WRITEBACK implies BDI_CAP_NO_ACCT_WB */ | |
215 | return !(bdi->capabilities & (BDI_CAP_NO_ACCT_WB | | |
216 | BDI_CAP_NO_WRITEBACK)); | |
217 | } | |
1da177e4 | 218 | |
e4ad08fe MS |
219 | static inline bool mapping_cap_writeback_dirty(struct address_space *mapping) |
220 | { | |
de1414a6 | 221 | return bdi_cap_writeback_dirty(inode_to_bdi(mapping->host)); |
e4ad08fe | 222 | } |
1da177e4 | 223 | |
e4ad08fe MS |
224 | static inline bool mapping_cap_account_dirty(struct address_space *mapping) |
225 | { | |
de1414a6 | 226 | return bdi_cap_account_dirty(inode_to_bdi(mapping->host)); |
e4ad08fe | 227 | } |
1da177e4 | 228 | |
03ba3782 JA |
229 | static inline int bdi_sched_wait(void *word) |
230 | { | |
231 | schedule(); | |
232 | return 0; | |
233 | } | |
234 | ||
89e9b9e0 TH |
235 | #ifdef CONFIG_CGROUP_WRITEBACK |
236 | ||
237 | /** | |
238 | * inode_cgwb_enabled - test whether cgroup writeback is enabled on an inode | |
239 | * @inode: inode of interest | |
240 | * | |
241 | * cgroup writeback requires support from both the bdi and filesystem. | |
242 | * Test whether @inode has both. | |
243 | */ | |
244 | static inline bool inode_cgwb_enabled(struct inode *inode) | |
245 | { | |
246 | struct backing_dev_info *bdi = inode_to_bdi(inode); | |
247 | ||
248 | return bdi_cap_account_dirty(bdi) && | |
249 | (bdi->capabilities & BDI_CAP_CGROUP_WRITEBACK) && | |
250 | (inode->i_sb->s_type->fs_flags & FS_CGROUP_WRITEBACK); | |
251 | } | |
252 | ||
253 | #else /* CONFIG_CGROUP_WRITEBACK */ | |
254 | ||
255 | static inline bool inode_cgwb_enabled(struct inode *inode) | |
256 | { | |
257 | return false; | |
258 | } | |
259 | ||
260 | #endif /* CONFIG_CGROUP_WRITEBACK */ | |
261 | ||
262 | #endif /* _LINUX_BACKING_DEV_H */ |