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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/device.h>
17#include <linux/writeback.h>
18#include <linux/blk-cgroup.h>
19#include <linux/backing-dev-defs.h>
20#include <linux/slab.h>
21
22static inline struct backing_dev_info *bdi_get(struct backing_dev_info *bdi)
23{
24 kref_get(&bdi->refcnt);
25 return bdi;
26}
27
28struct backing_dev_info *bdi_get_by_id(u64 id);
29void bdi_put(struct backing_dev_info *bdi);
30
31__printf(2, 3)
32int bdi_register(struct backing_dev_info *bdi, const char *fmt, ...);
33__printf(2, 0)
34int bdi_register_va(struct backing_dev_info *bdi, const char *fmt,
35 va_list args);
36void bdi_set_owner(struct backing_dev_info *bdi, struct device *owner);
37void bdi_unregister(struct backing_dev_info *bdi);
38
39struct backing_dev_info *bdi_alloc(int node_id);
40
41void wb_start_background_writeback(struct bdi_writeback *wb);
42void wb_workfn(struct work_struct *work);
43void wb_wakeup_delayed(struct bdi_writeback *wb);
44
45void wb_wait_for_completion(struct wb_completion *done);
46
47extern spinlock_t bdi_lock;
48extern struct list_head bdi_list;
49
50extern struct workqueue_struct *bdi_wq;
51extern struct workqueue_struct *bdi_async_bio_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(void)
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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117
118#define BDI_CAP_WRITEBACK (1 << 0)
119#define BDI_CAP_WRITEBACK_ACCT (1 << 1)
120#define BDI_CAP_STRICTLIMIT (1 << 2)
121
122extern struct backing_dev_info noop_backing_dev_info;
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131static inline bool writeback_in_progress(struct bdi_writeback *wb)
132{
133 return test_bit(WB_writeback_running, &wb->state);
134}
135
136static inline struct backing_dev_info *inode_to_bdi(struct inode *inode)
137{
138 struct super_block *sb;
139
140 if (!inode)
141 return &noop_backing_dev_info;
142
143 sb = inode->i_sb;
144#ifdef CONFIG_BLOCK
145 if (sb_is_blkdev_sb(sb))
146 return I_BDEV(inode)->bd_bdi;
147#endif
148 return sb->s_bdi;
149}
150
151static inline int wb_congested(struct bdi_writeback *wb, int cong_bits)
152{
153 return wb->congested & cong_bits;
154}
155
156long congestion_wait(int sync, long timeout);
157long wait_iff_congested(int sync, long timeout);
158
159static inline bool mapping_can_writeback(struct address_space *mapping)
160{
161 return inode_to_bdi(mapping->host)->capabilities & BDI_CAP_WRITEBACK;
162}
163
164static inline int bdi_sched_wait(void *word)
165{
166 schedule();
167 return 0;
168}
169
170#ifdef CONFIG_CGROUP_WRITEBACK
171
172struct bdi_writeback *wb_get_lookup(struct backing_dev_info *bdi,
173 struct cgroup_subsys_state *memcg_css);
174struct bdi_writeback *wb_get_create(struct backing_dev_info *bdi,
175 struct cgroup_subsys_state *memcg_css,
176 gfp_t gfp);
177void wb_memcg_offline(struct mem_cgroup *memcg);
178void wb_blkcg_offline(struct blkcg *blkcg);
179int inode_congested(struct inode *inode, int cong_bits);
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192static inline bool inode_cgwb_enabled(struct inode *inode)
193{
194 struct backing_dev_info *bdi = inode_to_bdi(inode);
195
196 return cgroup_subsys_on_dfl(memory_cgrp_subsys) &&
197 cgroup_subsys_on_dfl(io_cgrp_subsys) &&
198 (bdi->capabilities & BDI_CAP_WRITEBACK) &&
199 (inode->i_sb->s_iflags & SB_I_CGROUPWB);
200}
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210static inline struct bdi_writeback *wb_find_current(struct backing_dev_info *bdi)
211{
212 struct cgroup_subsys_state *memcg_css;
213 struct bdi_writeback *wb;
214
215 memcg_css = task_css(current, memory_cgrp_id);
216 if (!memcg_css->parent)
217 return &bdi->wb;
218
219 wb = radix_tree_lookup(&bdi->cgwb_tree, memcg_css->id);
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225 if (likely(wb && wb->blkcg_css == task_css(current, io_cgrp_id)))
226 return wb;
227 return NULL;
228}
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239static inline struct bdi_writeback *
240wb_get_create_current(struct backing_dev_info *bdi, gfp_t gfp)
241{
242 struct bdi_writeback *wb;
243
244 rcu_read_lock();
245 wb = wb_find_current(bdi);
246 if (wb && unlikely(!wb_tryget(wb)))
247 wb = NULL;
248 rcu_read_unlock();
249
250 if (unlikely(!wb)) {
251 struct cgroup_subsys_state *memcg_css;
252
253 memcg_css = task_get_css(current, memory_cgrp_id);
254 wb = wb_get_create(bdi, memcg_css, gfp);
255 css_put(memcg_css);
256 }
257 return wb;
258}
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267static inline bool inode_to_wb_is_valid(struct inode *inode)
268{
269 return inode->i_wb;
270}
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280static inline struct bdi_writeback *inode_to_wb(const struct inode *inode)
281{
282#ifdef CONFIG_LOCKDEP
283 WARN_ON_ONCE(debug_locks &&
284 (!lockdep_is_held(&inode->i_lock) &&
285 !lockdep_is_held(&inode->i_mapping->i_pages.xa_lock) &&
286 !lockdep_is_held(&inode->i_wb->list_lock)));
287#endif
288 return inode->i_wb;
289}
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306static inline struct bdi_writeback *
307unlocked_inode_to_wb_begin(struct inode *inode, struct wb_lock_cookie *cookie)
308{
309 rcu_read_lock();
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315 cookie->locked = smp_load_acquire(&inode->i_state) & I_WB_SWITCH;
316
317 if (unlikely(cookie->locked))
318 xa_lock_irqsave(&inode->i_mapping->i_pages, cookie->flags);
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324 return inode->i_wb;
325}
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332static inline void unlocked_inode_to_wb_end(struct inode *inode,
333 struct wb_lock_cookie *cookie)
334{
335 if (unlikely(cookie->locked))
336 xa_unlock_irqrestore(&inode->i_mapping->i_pages, cookie->flags);
337
338 rcu_read_unlock();
339}
340
341#else
342
343static inline bool inode_cgwb_enabled(struct inode *inode)
344{
345 return false;
346}
347
348static inline struct bdi_writeback *wb_find_current(struct backing_dev_info *bdi)
349{
350 return &bdi->wb;
351}
352
353static inline struct bdi_writeback *
354wb_get_create_current(struct backing_dev_info *bdi, gfp_t gfp)
355{
356 return &bdi->wb;
357}
358
359static inline bool inode_to_wb_is_valid(struct inode *inode)
360{
361 return true;
362}
363
364static inline struct bdi_writeback *inode_to_wb(struct inode *inode)
365{
366 return &inode_to_bdi(inode)->wb;
367}
368
369static inline struct bdi_writeback *
370unlocked_inode_to_wb_begin(struct inode *inode, struct wb_lock_cookie *cookie)
371{
372 return inode_to_wb(inode);
373}
374
375static inline void unlocked_inode_to_wb_end(struct inode *inode,
376 struct wb_lock_cookie *cookie)
377{
378}
379
380static inline void wb_memcg_offline(struct mem_cgroup *memcg)
381{
382}
383
384static inline void wb_blkcg_offline(struct blkcg *blkcg)
385{
386}
387
388static inline int inode_congested(struct inode *inode, int cong_bits)
389{
390 return wb_congested(&inode_to_bdi(inode)->wb, cong_bits);
391}
392
393#endif
394
395static inline int inode_read_congested(struct inode *inode)
396{
397 return inode_congested(inode, 1 << WB_sync_congested);
398}
399
400static inline int inode_write_congested(struct inode *inode)
401{
402 return inode_congested(inode, 1 << WB_async_congested);
403}
404
405static inline int inode_rw_congested(struct inode *inode)
406{
407 return inode_congested(inode, (1 << WB_sync_congested) |
408 (1 << WB_async_congested));
409}
410
411static inline int bdi_congested(struct backing_dev_info *bdi, int cong_bits)
412{
413 return wb_congested(&bdi->wb, cong_bits);
414}
415
416static inline int bdi_read_congested(struct backing_dev_info *bdi)
417{
418 return bdi_congested(bdi, 1 << WB_sync_congested);
419}
420
421static inline int bdi_write_congested(struct backing_dev_info *bdi)
422{
423 return bdi_congested(bdi, 1 << WB_async_congested);
424}
425
426static inline int bdi_rw_congested(struct backing_dev_info *bdi)
427{
428 return bdi_congested(bdi, (1 << WB_sync_congested) |
429 (1 << WB_async_congested));
430}
431
432const char *bdi_dev_name(struct backing_dev_info *bdi);
433
434#endif
435