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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, ...);
31__printf(2, 0)
32int bdi_register_va(struct backing_dev_info *bdi, const char *fmt,
33 va_list args);
34int bdi_register_owner(struct backing_dev_info *bdi, struct device *owner);
35void bdi_unregister(struct backing_dev_info *bdi);
36
37struct backing_dev_info *bdi_alloc_node(gfp_t gfp_mask, int node_id);
38static inline struct backing_dev_info *bdi_alloc(gfp_t gfp_mask)
39{
40 return bdi_alloc_node(gfp_mask, NUMA_NO_NODE);
41}
42
43void wb_start_background_writeback(struct bdi_writeback *wb);
44void wb_workfn(struct work_struct *work);
45void wb_wakeup_delayed(struct bdi_writeback *wb);
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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130#define BDI_CAP_NO_ACCT_DIRTY 0x00000001
131#define BDI_CAP_NO_WRITEBACK 0x00000002
132#define BDI_CAP_NO_ACCT_WB 0x00000004
133#define BDI_CAP_STABLE_WRITES 0x00000008
134#define BDI_CAP_STRICTLIMIT 0x00000010
135#define BDI_CAP_CGROUP_WRITEBACK 0x00000020
136#define BDI_CAP_SYNCHRONOUS_IO 0x00000040
137
138#define BDI_CAP_NO_ACCT_AND_WRITEBACK \
139 (BDI_CAP_NO_WRITEBACK | BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_ACCT_WB)
140
141extern struct backing_dev_info noop_backing_dev_info;
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150static inline bool writeback_in_progress(struct bdi_writeback *wb)
151{
152 return test_bit(WB_writeback_running, &wb->state);
153}
154
155static inline struct backing_dev_info *inode_to_bdi(struct inode *inode)
156{
157 struct super_block *sb;
158
159 if (!inode)
160 return &noop_backing_dev_info;
161
162 sb = inode->i_sb;
163#ifdef CONFIG_BLOCK
164 if (sb_is_blkdev_sb(sb))
165 return I_BDEV(inode)->bd_bdi;
166#endif
167 return sb->s_bdi;
168}
169
170static inline int wb_congested(struct bdi_writeback *wb, int cong_bits)
171{
172 struct backing_dev_info *bdi = wb->bdi;
173
174 if (bdi->congested_fn)
175 return bdi->congested_fn(bdi->congested_data, cong_bits);
176 return wb->congested->state & cong_bits;
177}
178
179long congestion_wait(int sync, long timeout);
180long wait_iff_congested(int sync, long timeout);
181
182static inline bool bdi_cap_synchronous_io(struct backing_dev_info *bdi)
183{
184 return bdi->capabilities & BDI_CAP_SYNCHRONOUS_IO;
185}
186
187static inline bool bdi_cap_stable_pages_required(struct backing_dev_info *bdi)
188{
189 return bdi->capabilities & BDI_CAP_STABLE_WRITES;
190}
191
192static inline bool bdi_cap_writeback_dirty(struct backing_dev_info *bdi)
193{
194 return !(bdi->capabilities & BDI_CAP_NO_WRITEBACK);
195}
196
197static inline bool bdi_cap_account_dirty(struct backing_dev_info *bdi)
198{
199 return !(bdi->capabilities & BDI_CAP_NO_ACCT_DIRTY);
200}
201
202static inline bool bdi_cap_account_writeback(struct backing_dev_info *bdi)
203{
204
205 return !(bdi->capabilities & (BDI_CAP_NO_ACCT_WB |
206 BDI_CAP_NO_WRITEBACK));
207}
208
209static inline bool mapping_cap_writeback_dirty(struct address_space *mapping)
210{
211 return bdi_cap_writeback_dirty(inode_to_bdi(mapping->host));
212}
213
214static inline bool mapping_cap_account_dirty(struct address_space *mapping)
215{
216 return bdi_cap_account_dirty(inode_to_bdi(mapping->host));
217}
218
219static inline int bdi_sched_wait(void *word)
220{
221 schedule();
222 return 0;
223}
224
225#ifdef CONFIG_CGROUP_WRITEBACK
226
227struct bdi_writeback_congested *
228wb_congested_get_create(struct backing_dev_info *bdi, int blkcg_id, gfp_t gfp);
229void wb_congested_put(struct bdi_writeback_congested *congested);
230struct bdi_writeback *wb_get_create(struct backing_dev_info *bdi,
231 struct cgroup_subsys_state *memcg_css,
232 gfp_t gfp);
233void wb_memcg_offline(struct mem_cgroup *memcg);
234void wb_blkcg_offline(struct blkcg *blkcg);
235int inode_congested(struct inode *inode, int cong_bits);
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248static inline bool inode_cgwb_enabled(struct inode *inode)
249{
250 struct backing_dev_info *bdi = inode_to_bdi(inode);
251
252 return cgroup_subsys_on_dfl(memory_cgrp_subsys) &&
253 cgroup_subsys_on_dfl(io_cgrp_subsys) &&
254 bdi_cap_account_dirty(bdi) &&
255 (bdi->capabilities & BDI_CAP_CGROUP_WRITEBACK) &&
256 (inode->i_sb->s_iflags & SB_I_CGROUPWB);
257}
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267static inline struct bdi_writeback *wb_find_current(struct backing_dev_info *bdi)
268{
269 struct cgroup_subsys_state *memcg_css;
270 struct bdi_writeback *wb;
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272 memcg_css = task_css(current, memory_cgrp_id);
273 if (!memcg_css->parent)
274 return &bdi->wb;
275
276 wb = radix_tree_lookup(&bdi->cgwb_tree, memcg_css->id);
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282 if (likely(wb && wb->blkcg_css == task_css(current, io_cgrp_id)))
283 return wb;
284 return NULL;
285}
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296static inline struct bdi_writeback *
297wb_get_create_current(struct backing_dev_info *bdi, gfp_t gfp)
298{
299 struct bdi_writeback *wb;
300
301 rcu_read_lock();
302 wb = wb_find_current(bdi);
303 if (wb && unlikely(!wb_tryget(wb)))
304 wb = NULL;
305 rcu_read_unlock();
306
307 if (unlikely(!wb)) {
308 struct cgroup_subsys_state *memcg_css;
309
310 memcg_css = task_get_css(current, memory_cgrp_id);
311 wb = wb_get_create(bdi, memcg_css, gfp);
312 css_put(memcg_css);
313 }
314 return wb;
315}
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324static inline bool inode_to_wb_is_valid(struct inode *inode)
325{
326 return inode->i_wb;
327}
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337static inline struct bdi_writeback *inode_to_wb(const struct inode *inode)
338{
339#ifdef CONFIG_LOCKDEP
340 WARN_ON_ONCE(debug_locks &&
341 (!lockdep_is_held(&inode->i_lock) &&
342 !lockdep_is_held(&inode->i_mapping->i_pages.xa_lock) &&
343 !lockdep_is_held(&inode->i_wb->list_lock)));
344#endif
345 return inode->i_wb;
346}
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363static inline struct bdi_writeback *
364unlocked_inode_to_wb_begin(struct inode *inode, struct wb_lock_cookie *cookie)
365{
366 rcu_read_lock();
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372 cookie->locked = smp_load_acquire(&inode->i_state) & I_WB_SWITCH;
373
374 if (unlikely(cookie->locked))
375 xa_lock_irqsave(&inode->i_mapping->i_pages, cookie->flags);
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381 return inode->i_wb;
382}
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389static inline void unlocked_inode_to_wb_end(struct inode *inode,
390 struct wb_lock_cookie *cookie)
391{
392 if (unlikely(cookie->locked))
393 xa_unlock_irqrestore(&inode->i_mapping->i_pages, cookie->flags);
394
395 rcu_read_unlock();
396}
397
398#else
399
400static inline bool inode_cgwb_enabled(struct inode *inode)
401{
402 return false;
403}
404
405static inline struct bdi_writeback_congested *
406wb_congested_get_create(struct backing_dev_info *bdi, int blkcg_id, gfp_t gfp)
407{
408 refcount_inc(&bdi->wb_congested->refcnt);
409 return bdi->wb_congested;
410}
411
412static inline void wb_congested_put(struct bdi_writeback_congested *congested)
413{
414 if (refcount_dec_and_test(&congested->refcnt))
415 kfree(congested);
416}
417
418static inline struct bdi_writeback *wb_find_current(struct backing_dev_info *bdi)
419{
420 return &bdi->wb;
421}
422
423static inline struct bdi_writeback *
424wb_get_create_current(struct backing_dev_info *bdi, gfp_t gfp)
425{
426 return &bdi->wb;
427}
428
429static inline bool inode_to_wb_is_valid(struct inode *inode)
430{
431 return true;
432}
433
434static inline struct bdi_writeback *inode_to_wb(struct inode *inode)
435{
436 return &inode_to_bdi(inode)->wb;
437}
438
439static inline struct bdi_writeback *
440unlocked_inode_to_wb_begin(struct inode *inode, struct wb_lock_cookie *cookie)
441{
442 return inode_to_wb(inode);
443}
444
445static inline void unlocked_inode_to_wb_end(struct inode *inode,
446 struct wb_lock_cookie *cookie)
447{
448}
449
450static inline void wb_memcg_offline(struct mem_cgroup *memcg)
451{
452}
453
454static inline void wb_blkcg_offline(struct blkcg *blkcg)
455{
456}
457
458static inline int inode_congested(struct inode *inode, int cong_bits)
459{
460 return wb_congested(&inode_to_bdi(inode)->wb, cong_bits);
461}
462
463#endif
464
465static inline int inode_read_congested(struct inode *inode)
466{
467 return inode_congested(inode, 1 << WB_sync_congested);
468}
469
470static inline int inode_write_congested(struct inode *inode)
471{
472 return inode_congested(inode, 1 << WB_async_congested);
473}
474
475static inline int inode_rw_congested(struct inode *inode)
476{
477 return inode_congested(inode, (1 << WB_sync_congested) |
478 (1 << WB_async_congested));
479}
480
481static inline int bdi_congested(struct backing_dev_info *bdi, int cong_bits)
482{
483 return wb_congested(&bdi->wb, cong_bits);
484}
485
486static inline int bdi_read_congested(struct backing_dev_info *bdi)
487{
488 return bdi_congested(bdi, 1 << WB_sync_congested);
489}
490
491static inline int bdi_write_congested(struct backing_dev_info *bdi)
492{
493 return bdi_congested(bdi, 1 << WB_async_congested);
494}
495
496static inline int bdi_rw_congested(struct backing_dev_info *bdi)
497{
498 return bdi_congested(bdi, (1 << WB_sync_congested) |
499 (1 << WB_async_congested));
500}
501
502#endif
503