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9#ifndef _LINUX_BACKING_DEV_H
10#define _LINUX_BACKING_DEV_H
11
12#include <linux/kernel.h>
13#include <linux/fs.h>
14#include <linux/sched.h>
15#include <linux/blkdev.h>
16#include <linux/writeback.h>
17#include <linux/blk-cgroup.h>
18#include <linux/backing-dev-defs.h>
19#include <linux/slab.h>
20
21static inline struct backing_dev_info *bdi_get(struct backing_dev_info *bdi)
22{
23 kref_get(&bdi->refcnt);
24 return bdi;
25}
26
27void bdi_put(struct backing_dev_info *bdi);
28
29__printf(2, 3)
30int bdi_register(struct backing_dev_info *bdi, const char *fmt, ...);
31int bdi_register_va(struct backing_dev_info *bdi, const char *fmt,
32 va_list args);
33int bdi_register_owner(struct backing_dev_info *bdi, struct device *owner);
34void bdi_unregister(struct backing_dev_info *bdi);
35
36struct backing_dev_info *bdi_alloc_node(gfp_t gfp_mask, int node_id);
37static inline struct backing_dev_info *bdi_alloc(gfp_t gfp_mask)
38{
39 return bdi_alloc_node(gfp_mask, NUMA_NO_NODE);
40}
41
42void wb_start_writeback(struct bdi_writeback *wb, long nr_pages,
43 bool range_cyclic, enum wb_reason reason);
44void wb_start_background_writeback(struct bdi_writeback *wb);
45void wb_workfn(struct work_struct *work);
46void wb_wakeup_delayed(struct bdi_writeback *wb);
47
48extern spinlock_t bdi_lock;
49extern struct list_head bdi_list;
50
51extern struct workqueue_struct *bdi_wq;
52
53static inline bool wb_has_dirty_io(struct bdi_writeback *wb)
54{
55 return test_bit(WB_has_dirty_io, &wb->state);
56}
57
58static inline bool bdi_has_dirty_io(struct backing_dev_info *bdi)
59{
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64 return atomic_long_read(&bdi->tot_write_bandwidth);
65}
66
67static inline void __add_wb_stat(struct bdi_writeback *wb,
68 enum wb_stat_item item, s64 amount)
69{
70 percpu_counter_add_batch(&wb->stat[item], amount, WB_STAT_BATCH);
71}
72
73static inline void inc_wb_stat(struct bdi_writeback *wb, enum wb_stat_item item)
74{
75 __add_wb_stat(wb, item, 1);
76}
77
78static inline void dec_wb_stat(struct bdi_writeback *wb, enum wb_stat_item item)
79{
80 __add_wb_stat(wb, item, -1);
81}
82
83static inline s64 wb_stat(struct bdi_writeback *wb, enum wb_stat_item item)
84{
85 return percpu_counter_read_positive(&wb->stat[item]);
86}
87
88static inline s64 wb_stat_sum(struct bdi_writeback *wb, enum wb_stat_item item)
89{
90 return percpu_counter_sum_positive(&wb->stat[item]);
91}
92
93extern void wb_writeout_inc(struct bdi_writeback *wb);
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98static inline unsigned long wb_stat_error(struct bdi_writeback *wb)
99{
100#ifdef CONFIG_SMP
101 return nr_cpu_ids * WB_STAT_BATCH;
102#else
103 return 1;
104#endif
105}
106
107int bdi_set_min_ratio(struct backing_dev_info *bdi, unsigned int min_ratio);
108int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ratio);
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128#define BDI_CAP_NO_ACCT_DIRTY 0x00000001
129#define BDI_CAP_NO_WRITEBACK 0x00000002
130#define BDI_CAP_NO_ACCT_WB 0x00000004
131#define BDI_CAP_STABLE_WRITES 0x00000008
132#define BDI_CAP_STRICTLIMIT 0x00000010
133#define BDI_CAP_CGROUP_WRITEBACK 0x00000020
134
135#define BDI_CAP_NO_ACCT_AND_WRITEBACK \
136 (BDI_CAP_NO_WRITEBACK | BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_ACCT_WB)
137
138extern struct backing_dev_info noop_backing_dev_info;
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147static inline bool writeback_in_progress(struct bdi_writeback *wb)
148{
149 return test_bit(WB_writeback_running, &wb->state);
150}
151
152static inline struct backing_dev_info *inode_to_bdi(struct inode *inode)
153{
154 struct super_block *sb;
155
156 if (!inode)
157 return &noop_backing_dev_info;
158
159 sb = inode->i_sb;
160#ifdef CONFIG_BLOCK
161 if (sb_is_blkdev_sb(sb))
162 return I_BDEV(inode)->bd_bdi;
163#endif
164 return sb->s_bdi;
165}
166
167static inline int wb_congested(struct bdi_writeback *wb, int cong_bits)
168{
169 struct backing_dev_info *bdi = wb->bdi;
170
171 if (bdi->congested_fn)
172 return bdi->congested_fn(bdi->congested_data, cong_bits);
173 return wb->congested->state & cong_bits;
174}
175
176long congestion_wait(int sync, long timeout);
177long wait_iff_congested(struct pglist_data *pgdat, int sync, long timeout);
178int pdflush_proc_obsolete(struct ctl_table *table, int write,
179 void __user *buffer, size_t *lenp, loff_t *ppos);
180
181static inline bool bdi_cap_stable_pages_required(struct backing_dev_info *bdi)
182{
183 return bdi->capabilities & BDI_CAP_STABLE_WRITES;
184}
185
186static inline bool bdi_cap_writeback_dirty(struct backing_dev_info *bdi)
187{
188 return !(bdi->capabilities & BDI_CAP_NO_WRITEBACK);
189}
190
191static inline bool bdi_cap_account_dirty(struct backing_dev_info *bdi)
192{
193 return !(bdi->capabilities & BDI_CAP_NO_ACCT_DIRTY);
194}
195
196static inline bool bdi_cap_account_writeback(struct backing_dev_info *bdi)
197{
198
199 return !(bdi->capabilities & (BDI_CAP_NO_ACCT_WB |
200 BDI_CAP_NO_WRITEBACK));
201}
202
203static inline bool mapping_cap_writeback_dirty(struct address_space *mapping)
204{
205 return bdi_cap_writeback_dirty(inode_to_bdi(mapping->host));
206}
207
208static inline bool mapping_cap_account_dirty(struct address_space *mapping)
209{
210 return bdi_cap_account_dirty(inode_to_bdi(mapping->host));
211}
212
213static inline int bdi_sched_wait(void *word)
214{
215 schedule();
216 return 0;
217}
218
219#ifdef CONFIG_CGROUP_WRITEBACK
220
221struct bdi_writeback_congested *
222wb_congested_get_create(struct backing_dev_info *bdi, int blkcg_id, gfp_t gfp);
223void wb_congested_put(struct bdi_writeback_congested *congested);
224struct bdi_writeback *wb_get_create(struct backing_dev_info *bdi,
225 struct cgroup_subsys_state *memcg_css,
226 gfp_t gfp);
227void wb_memcg_offline(struct mem_cgroup *memcg);
228void wb_blkcg_offline(struct blkcg *blkcg);
229int inode_congested(struct inode *inode, int cong_bits);
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242static inline bool inode_cgwb_enabled(struct inode *inode)
243{
244 struct backing_dev_info *bdi = inode_to_bdi(inode);
245
246 return cgroup_subsys_on_dfl(memory_cgrp_subsys) &&
247 cgroup_subsys_on_dfl(io_cgrp_subsys) &&
248 bdi_cap_account_dirty(bdi) &&
249 (bdi->capabilities & BDI_CAP_CGROUP_WRITEBACK) &&
250 (inode->i_sb->s_iflags & SB_I_CGROUPWB);
251}
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261static inline struct bdi_writeback *wb_find_current(struct backing_dev_info *bdi)
262{
263 struct cgroup_subsys_state *memcg_css;
264 struct bdi_writeback *wb;
265
266 memcg_css = task_css(current, memory_cgrp_id);
267 if (!memcg_css->parent)
268 return &bdi->wb;
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270 wb = radix_tree_lookup(&bdi->cgwb_tree, memcg_css->id);
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276 if (likely(wb && wb->blkcg_css == task_css(current, io_cgrp_id)))
277 return wb;
278 return NULL;
279}
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290static inline struct bdi_writeback *
291wb_get_create_current(struct backing_dev_info *bdi, gfp_t gfp)
292{
293 struct bdi_writeback *wb;
294
295 rcu_read_lock();
296 wb = wb_find_current(bdi);
297 if (wb && unlikely(!wb_tryget(wb)))
298 wb = NULL;
299 rcu_read_unlock();
300
301 if (unlikely(!wb)) {
302 struct cgroup_subsys_state *memcg_css;
303
304 memcg_css = task_get_css(current, memory_cgrp_id);
305 wb = wb_get_create(bdi, memcg_css, gfp);
306 css_put(memcg_css);
307 }
308 return wb;
309}
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318static inline bool inode_to_wb_is_valid(struct inode *inode)
319{
320 return inode->i_wb;
321}
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331static inline struct bdi_writeback *inode_to_wb(struct inode *inode)
332{
333#ifdef CONFIG_LOCKDEP
334 WARN_ON_ONCE(debug_locks &&
335 (!lockdep_is_held(&inode->i_lock) &&
336 !lockdep_is_held(&inode->i_mapping->tree_lock) &&
337 !lockdep_is_held(&inode->i_wb->list_lock)));
338#endif
339 return inode->i_wb;
340}
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357static inline struct bdi_writeback *
358unlocked_inode_to_wb_begin(struct inode *inode, bool *lockedp)
359{
360 rcu_read_lock();
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366 *lockedp = smp_load_acquire(&inode->i_state) & I_WB_SWITCH;
367
368 if (unlikely(*lockedp))
369 spin_lock_irq(&inode->i_mapping->tree_lock);
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375 return inode->i_wb;
376}
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383static inline void unlocked_inode_to_wb_end(struct inode *inode, bool locked)
384{
385 if (unlikely(locked))
386 spin_unlock_irq(&inode->i_mapping->tree_lock);
387
388 rcu_read_unlock();
389}
390
391#else
392
393static inline bool inode_cgwb_enabled(struct inode *inode)
394{
395 return false;
396}
397
398static inline struct bdi_writeback_congested *
399wb_congested_get_create(struct backing_dev_info *bdi, int blkcg_id, gfp_t gfp)
400{
401 atomic_inc(&bdi->wb_congested->refcnt);
402 return bdi->wb_congested;
403}
404
405static inline void wb_congested_put(struct bdi_writeback_congested *congested)
406{
407 if (atomic_dec_and_test(&congested->refcnt))
408 kfree(congested);
409}
410
411static inline struct bdi_writeback *wb_find_current(struct backing_dev_info *bdi)
412{
413 return &bdi->wb;
414}
415
416static inline struct bdi_writeback *
417wb_get_create_current(struct backing_dev_info *bdi, gfp_t gfp)
418{
419 return &bdi->wb;
420}
421
422static inline bool inode_to_wb_is_valid(struct inode *inode)
423{
424 return true;
425}
426
427static inline struct bdi_writeback *inode_to_wb(struct inode *inode)
428{
429 return &inode_to_bdi(inode)->wb;
430}
431
432static inline struct bdi_writeback *
433unlocked_inode_to_wb_begin(struct inode *inode, bool *lockedp)
434{
435 return inode_to_wb(inode);
436}
437
438static inline void unlocked_inode_to_wb_end(struct inode *inode, bool locked)
439{
440}
441
442static inline void wb_memcg_offline(struct mem_cgroup *memcg)
443{
444}
445
446static inline void wb_blkcg_offline(struct blkcg *blkcg)
447{
448}
449
450static inline int inode_congested(struct inode *inode, int cong_bits)
451{
452 return wb_congested(&inode_to_bdi(inode)->wb, cong_bits);
453}
454
455#endif
456
457static inline int inode_read_congested(struct inode *inode)
458{
459 return inode_congested(inode, 1 << WB_sync_congested);
460}
461
462static inline int inode_write_congested(struct inode *inode)
463{
464 return inode_congested(inode, 1 << WB_async_congested);
465}
466
467static inline int inode_rw_congested(struct inode *inode)
468{
469 return inode_congested(inode, (1 << WB_sync_congested) |
470 (1 << WB_async_congested));
471}
472
473static inline int bdi_congested(struct backing_dev_info *bdi, int cong_bits)
474{
475 return wb_congested(&bdi->wb, cong_bits);
476}
477
478static inline int bdi_read_congested(struct backing_dev_info *bdi)
479{
480 return bdi_congested(bdi, 1 << WB_sync_congested);
481}
482
483static inline int bdi_write_congested(struct backing_dev_info *bdi)
484{
485 return bdi_congested(bdi, 1 << WB_async_congested);
486}
487
488static inline int bdi_rw_congested(struct backing_dev_info *bdi)
489{
490 return bdi_congested(bdi, (1 << WB_sync_congested) |
491 (1 << WB_async_congested));
492}
493
494#endif
495