1
2
3
4
5
6
7
8#ifndef _LINUX_BACKING_DEV_H
9#define _LINUX_BACKING_DEV_H
10
11#include <linux/kernel.h>
12#include <linux/fs.h>
13#include <linux/sched.h>
14#include <linux/blkdev.h>
15#include <linux/writeback.h>
16#include <linux/blk-cgroup.h>
17#include <linux/backing-dev-defs.h>
18#include <linux/slab.h>
19
20int __must_check bdi_init(struct backing_dev_info *bdi);
21void bdi_exit(struct backing_dev_info *bdi);
22
23__printf(3, 4)
24int bdi_register(struct backing_dev_info *bdi, struct device *parent,
25 const char *fmt, ...);
26int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev);
27int bdi_register_owner(struct backing_dev_info *bdi, struct device *owner);
28void bdi_unregister(struct backing_dev_info *bdi);
29
30int __must_check bdi_setup_and_register(struct backing_dev_info *, char *);
31void bdi_destroy(struct backing_dev_info *bdi);
32
33void wb_start_writeback(struct bdi_writeback *wb, long nr_pages,
34 bool range_cyclic, enum wb_reason reason);
35void wb_start_background_writeback(struct bdi_writeback *wb);
36void wb_workfn(struct work_struct *work);
37void wb_wakeup_delayed(struct bdi_writeback *wb);
38
39extern spinlock_t bdi_lock;
40extern struct list_head bdi_list;
41
42extern struct workqueue_struct *bdi_wq;
43
44static inline bool wb_has_dirty_io(struct bdi_writeback *wb)
45{
46 return test_bit(WB_has_dirty_io, &wb->state);
47}
48
49static inline bool bdi_has_dirty_io(struct backing_dev_info *bdi)
50{
51
52
53
54
55 return atomic_long_read(&bdi->tot_write_bandwidth);
56}
57
58static inline void __add_wb_stat(struct bdi_writeback *wb,
59 enum wb_stat_item item, s64 amount)
60{
61 __percpu_counter_add(&wb->stat[item], amount, WB_STAT_BATCH);
62}
63
64static inline void __inc_wb_stat(struct bdi_writeback *wb,
65 enum wb_stat_item item)
66{
67 __add_wb_stat(wb, item, 1);
68}
69
70static inline void inc_wb_stat(struct bdi_writeback *wb, enum wb_stat_item item)
71{
72 unsigned long flags;
73
74 local_irq_save(flags);
75 __inc_wb_stat(wb, item);
76 local_irq_restore(flags);
77}
78
79static inline void __dec_wb_stat(struct bdi_writeback *wb,
80 enum wb_stat_item item)
81{
82 __add_wb_stat(wb, item, -1);
83}
84
85static inline void dec_wb_stat(struct bdi_writeback *wb, enum wb_stat_item item)
86{
87 unsigned long flags;
88
89 local_irq_save(flags);
90 __dec_wb_stat(wb, item);
91 local_irq_restore(flags);
92}
93
94static inline s64 wb_stat(struct bdi_writeback *wb, enum wb_stat_item item)
95{
96 return percpu_counter_read_positive(&wb->stat[item]);
97}
98
99static inline s64 __wb_stat_sum(struct bdi_writeback *wb,
100 enum wb_stat_item item)
101{
102 return percpu_counter_sum_positive(&wb->stat[item]);
103}
104
105static inline s64 wb_stat_sum(struct bdi_writeback *wb, enum wb_stat_item item)
106{
107 s64 sum;
108 unsigned long flags;
109
110 local_irq_save(flags);
111 sum = __wb_stat_sum(wb, item);
112 local_irq_restore(flags);
113
114 return sum;
115}
116
117extern void wb_writeout_inc(struct bdi_writeback *wb);
118
119
120
121
122static inline unsigned long wb_stat_error(struct bdi_writeback *wb)
123{
124#ifdef CONFIG_SMP
125 return nr_cpu_ids * WB_STAT_BATCH;
126#else
127 return 1;
128#endif
129}
130
131int bdi_set_min_ratio(struct backing_dev_info *bdi, unsigned int min_ratio);
132int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ratio);
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152#define BDI_CAP_NO_ACCT_DIRTY 0x00000001
153#define BDI_CAP_NO_WRITEBACK 0x00000002
154#define BDI_CAP_NO_ACCT_WB 0x00000004
155#define BDI_CAP_STABLE_WRITES 0x00000008
156#define BDI_CAP_STRICTLIMIT 0x00000010
157#define BDI_CAP_CGROUP_WRITEBACK 0x00000020
158
159#define BDI_CAP_NO_ACCT_AND_WRITEBACK \
160 (BDI_CAP_NO_WRITEBACK | BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_ACCT_WB)
161
162extern struct backing_dev_info noop_backing_dev_info;
163
164
165
166
167
168
169
170
171static inline bool writeback_in_progress(struct bdi_writeback *wb)
172{
173 return test_bit(WB_writeback_running, &wb->state);
174}
175
176static inline struct backing_dev_info *inode_to_bdi(struct inode *inode)
177{
178 struct super_block *sb;
179
180 if (!inode)
181 return &noop_backing_dev_info;
182
183 sb = inode->i_sb;
184#ifdef CONFIG_BLOCK
185 if (sb_is_blkdev_sb(sb))
186 return blk_get_backing_dev_info(I_BDEV(inode));
187#endif
188 return sb->s_bdi;
189}
190
191static inline int wb_congested(struct bdi_writeback *wb, int cong_bits)
192{
193 struct backing_dev_info *bdi = wb->bdi;
194
195 if (bdi->congested_fn)
196 return bdi->congested_fn(bdi->congested_data, cong_bits);
197 return wb->congested->state & cong_bits;
198}
199
200long congestion_wait(int sync, long timeout);
201long wait_iff_congested(struct pglist_data *pgdat, int sync, long timeout);
202int pdflush_proc_obsolete(struct ctl_table *table, int write,
203 void __user *buffer, size_t *lenp, loff_t *ppos);
204
205static inline bool bdi_cap_stable_pages_required(struct backing_dev_info *bdi)
206{
207 return bdi->capabilities & BDI_CAP_STABLE_WRITES;
208}
209
210static inline bool bdi_cap_writeback_dirty(struct backing_dev_info *bdi)
211{
212 return !(bdi->capabilities & BDI_CAP_NO_WRITEBACK);
213}
214
215static inline bool bdi_cap_account_dirty(struct backing_dev_info *bdi)
216{
217 return !(bdi->capabilities & BDI_CAP_NO_ACCT_DIRTY);
218}
219
220static inline bool bdi_cap_account_writeback(struct backing_dev_info *bdi)
221{
222
223 return !(bdi->capabilities & (BDI_CAP_NO_ACCT_WB |
224 BDI_CAP_NO_WRITEBACK));
225}
226
227static inline bool mapping_cap_writeback_dirty(struct address_space *mapping)
228{
229 return bdi_cap_writeback_dirty(inode_to_bdi(mapping->host));
230}
231
232static inline bool mapping_cap_account_dirty(struct address_space *mapping)
233{
234 return bdi_cap_account_dirty(inode_to_bdi(mapping->host));
235}
236
237static inline int bdi_sched_wait(void *word)
238{
239 schedule();
240 return 0;
241}
242
243#ifdef CONFIG_CGROUP_WRITEBACK
244
245struct bdi_writeback_congested *
246wb_congested_get_create(struct backing_dev_info *bdi, int blkcg_id, gfp_t gfp);
247void wb_congested_put(struct bdi_writeback_congested *congested);
248struct bdi_writeback *wb_get_create(struct backing_dev_info *bdi,
249 struct cgroup_subsys_state *memcg_css,
250 gfp_t gfp);
251void wb_memcg_offline(struct mem_cgroup *memcg);
252void wb_blkcg_offline(struct blkcg *blkcg);
253int inode_congested(struct inode *inode, int cong_bits);
254
255
256
257
258
259
260
261
262
263
264
265
266static inline bool inode_cgwb_enabled(struct inode *inode)
267{
268 struct backing_dev_info *bdi = inode_to_bdi(inode);
269
270 return cgroup_subsys_on_dfl(memory_cgrp_subsys) &&
271 cgroup_subsys_on_dfl(io_cgrp_subsys) &&
272 bdi_cap_account_dirty(bdi) &&
273 (bdi->capabilities & BDI_CAP_CGROUP_WRITEBACK) &&
274 (inode->i_sb->s_iflags & SB_I_CGROUPWB);
275}
276
277
278
279
280
281
282
283
284
285static inline struct bdi_writeback *wb_find_current(struct backing_dev_info *bdi)
286{
287 struct cgroup_subsys_state *memcg_css;
288 struct bdi_writeback *wb;
289
290 memcg_css = task_css(current, memory_cgrp_id);
291 if (!memcg_css->parent)
292 return &bdi->wb;
293
294 wb = radix_tree_lookup(&bdi->cgwb_tree, memcg_css->id);
295
296
297
298
299
300 if (likely(wb && wb->blkcg_css == task_css(current, io_cgrp_id)))
301 return wb;
302 return NULL;
303}
304
305
306
307
308
309
310
311
312
313
314static inline struct bdi_writeback *
315wb_get_create_current(struct backing_dev_info *bdi, gfp_t gfp)
316{
317 struct bdi_writeback *wb;
318
319 rcu_read_lock();
320 wb = wb_find_current(bdi);
321 if (wb && unlikely(!wb_tryget(wb)))
322 wb = NULL;
323 rcu_read_unlock();
324
325 if (unlikely(!wb)) {
326 struct cgroup_subsys_state *memcg_css;
327
328 memcg_css = task_get_css(current, memory_cgrp_id);
329 wb = wb_get_create(bdi, memcg_css, gfp);
330 css_put(memcg_css);
331 }
332 return wb;
333}
334
335
336
337
338
339
340
341
342static inline bool inode_to_wb_is_valid(struct inode *inode)
343{
344 return inode->i_wb;
345}
346
347
348
349
350
351
352
353
354
355static inline struct bdi_writeback *inode_to_wb(struct inode *inode)
356{
357#ifdef CONFIG_LOCKDEP
358 WARN_ON_ONCE(debug_locks &&
359 (!lockdep_is_held(&inode->i_lock) &&
360 !lockdep_is_held(&inode->i_mapping->tree_lock) &&
361 !lockdep_is_held(&inode->i_wb->list_lock)));
362#endif
363 return inode->i_wb;
364}
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381static inline struct bdi_writeback *
382unlocked_inode_to_wb_begin(struct inode *inode, bool *lockedp)
383{
384 rcu_read_lock();
385
386
387
388
389
390 *lockedp = smp_load_acquire(&inode->i_state) & I_WB_SWITCH;
391
392 if (unlikely(*lockedp))
393 spin_lock_irq(&inode->i_mapping->tree_lock);
394
395
396
397
398
399 return inode->i_wb;
400}
401
402
403
404
405
406
407static inline void unlocked_inode_to_wb_end(struct inode *inode, bool locked)
408{
409 if (unlikely(locked))
410 spin_unlock_irq(&inode->i_mapping->tree_lock);
411
412 rcu_read_unlock();
413}
414
415#else
416
417static inline bool inode_cgwb_enabled(struct inode *inode)
418{
419 return false;
420}
421
422static inline struct bdi_writeback_congested *
423wb_congested_get_create(struct backing_dev_info *bdi, int blkcg_id, gfp_t gfp)
424{
425 atomic_inc(&bdi->wb_congested->refcnt);
426 return bdi->wb_congested;
427}
428
429static inline void wb_congested_put(struct bdi_writeback_congested *congested)
430{
431 if (atomic_dec_and_test(&congested->refcnt))
432 kfree(congested);
433}
434
435static inline struct bdi_writeback *wb_find_current(struct backing_dev_info *bdi)
436{
437 return &bdi->wb;
438}
439
440static inline struct bdi_writeback *
441wb_get_create_current(struct backing_dev_info *bdi, gfp_t gfp)
442{
443 return &bdi->wb;
444}
445
446static inline bool inode_to_wb_is_valid(struct inode *inode)
447{
448 return true;
449}
450
451static inline struct bdi_writeback *inode_to_wb(struct inode *inode)
452{
453 return &inode_to_bdi(inode)->wb;
454}
455
456static inline struct bdi_writeback *
457unlocked_inode_to_wb_begin(struct inode *inode, bool *lockedp)
458{
459 return inode_to_wb(inode);
460}
461
462static inline void unlocked_inode_to_wb_end(struct inode *inode, bool locked)
463{
464}
465
466static inline void wb_memcg_offline(struct mem_cgroup *memcg)
467{
468}
469
470static inline void wb_blkcg_offline(struct blkcg *blkcg)
471{
472}
473
474static inline int inode_congested(struct inode *inode, int cong_bits)
475{
476 return wb_congested(&inode_to_bdi(inode)->wb, cong_bits);
477}
478
479#endif
480
481static inline int inode_read_congested(struct inode *inode)
482{
483 return inode_congested(inode, 1 << WB_sync_congested);
484}
485
486static inline int inode_write_congested(struct inode *inode)
487{
488 return inode_congested(inode, 1 << WB_async_congested);
489}
490
491static inline int inode_rw_congested(struct inode *inode)
492{
493 return inode_congested(inode, (1 << WB_sync_congested) |
494 (1 << WB_async_congested));
495}
496
497static inline int bdi_congested(struct backing_dev_info *bdi, int cong_bits)
498{
499 return wb_congested(&bdi->wb, cong_bits);
500}
501
502static inline int bdi_read_congested(struct backing_dev_info *bdi)
503{
504 return bdi_congested(bdi, 1 << WB_sync_congested);
505}
506
507static inline int bdi_write_congested(struct backing_dev_info *bdi)
508{
509 return bdi_congested(bdi, 1 << WB_async_congested);
510}
511
512static inline int bdi_rw_congested(struct backing_dev_info *bdi)
513{
514 return bdi_congested(bdi, (1 << WB_sync_congested) |
515 (1 << WB_async_congested));
516}
517
518#endif
519