Commit | Line | Data |
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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
1da177e4 LT |
2 | /* |
3 | * include/linux/backing-dev.h | |
4 | * | |
5 | * low-level device information and state which is propagated up through | |
6 | * to high-level code. | |
7 | */ | |
8 | ||
9 | #ifndef _LINUX_BACKING_DEV_H | |
10 | #define _LINUX_BACKING_DEV_H | |
11 | ||
cf0ca9fe | 12 | #include <linux/kernel.h> |
e4ad08fe | 13 | #include <linux/fs.h> |
03ba3782 | 14 | #include <linux/sched.h> |
68f23b89 | 15 | #include <linux/device.h> |
03ba3782 | 16 | #include <linux/writeback.h> |
66114cad | 17 | #include <linux/backing-dev-defs.h> |
a13f35e8 | 18 | #include <linux/slab.h> |
de1414a6 | 19 | |
e41d12f5 CH |
20 | struct blkcg; |
21 | ||
d03f6cdc JK |
22 | static inline struct backing_dev_info *bdi_get(struct backing_dev_info *bdi) |
23 | { | |
24 | kref_get(&bdi->refcnt); | |
25 | return bdi; | |
26 | } | |
27 | ||
34f8fe50 | 28 | struct backing_dev_info *bdi_get_by_id(u64 id); |
d03f6cdc | 29 | void bdi_put(struct backing_dev_info *bdi); |
b2e8fb6e | 30 | |
7c4cc300 JK |
31 | __printf(2, 3) |
32 | int bdi_register(struct backing_dev_info *bdi, const char *fmt, ...); | |
a93f00b3 | 33 | __printf(2, 0) |
7c4cc300 JK |
34 | int bdi_register_va(struct backing_dev_info *bdi, const char *fmt, |
35 | va_list args); | |
3c5d202b | 36 | void bdi_set_owner(struct backing_dev_info *bdi, struct device *owner); |
b02176f3 TH |
37 | void bdi_unregister(struct backing_dev_info *bdi); |
38 | ||
aef33c2f | 39 | struct backing_dev_info *bdi_alloc(int node_id); |
b02176f3 | 40 | |
9ecf4866 | 41 | void wb_start_background_writeback(struct bdi_writeback *wb); |
f0054bb1 | 42 | void wb_workfn(struct work_struct *work); |
f0054bb1 | 43 | void wb_wakeup_delayed(struct bdi_writeback *wb); |
cf0ca9fe | 44 | |
5b9cce4c TH |
45 | void wb_wait_for_completion(struct wb_completion *done); |
46 | ||
03ba3782 | 47 | extern spinlock_t bdi_lock; |
66f3b8e2 JA |
48 | extern struct list_head bdi_list; |
49 | ||
839a8e86 | 50 | extern struct workqueue_struct *bdi_wq; |
d3f77dfd | 51 | extern struct workqueue_struct *bdi_async_bio_wq; |
839a8e86 | 52 | |
d6c10f1f | 53 | static inline bool wb_has_dirty_io(struct bdi_writeback *wb) |
03ba3782 | 54 | { |
d6c10f1f | 55 | return test_bit(WB_has_dirty_io, &wb->state); |
03ba3782 JA |
56 | } |
57 | ||
95a46c65 TH |
58 | static inline bool bdi_has_dirty_io(struct backing_dev_info *bdi) |
59 | { | |
60 | /* | |
61 | * @bdi->tot_write_bandwidth is guaranteed to be > 0 if there are | |
62 | * any dirty wbs. See wb_update_write_bandwidth(). | |
63 | */ | |
64 | return atomic_long_read(&bdi->tot_write_bandwidth); | |
03ba3782 JA |
65 | } |
66 | ||
bd3488e7 | 67 | static inline void wb_stat_mod(struct bdi_writeback *wb, |
93f78d88 | 68 | enum wb_stat_item item, s64 amount) |
b2e8fb6e | 69 | { |
104b4e51 | 70 | percpu_counter_add_batch(&wb->stat[item], amount, WB_STAT_BATCH); |
b2e8fb6e PZ |
71 | } |
72 | ||
93f78d88 | 73 | static inline void inc_wb_stat(struct bdi_writeback *wb, enum wb_stat_item item) |
b2e8fb6e | 74 | { |
bd3488e7 | 75 | wb_stat_mod(wb, item, 1); |
b2e8fb6e PZ |
76 | } |
77 | ||
93f78d88 | 78 | static inline void dec_wb_stat(struct bdi_writeback *wb, enum wb_stat_item item) |
b2e8fb6e | 79 | { |
bd3488e7 | 80 | wb_stat_mod(wb, item, -1); |
b2e8fb6e PZ |
81 | } |
82 | ||
93f78d88 | 83 | static inline s64 wb_stat(struct bdi_writeback *wb, enum wb_stat_item item) |
b2e8fb6e | 84 | { |
93f78d88 | 85 | return percpu_counter_read_positive(&wb->stat[item]); |
b2e8fb6e PZ |
86 | } |
87 | ||
93f78d88 | 88 | static inline s64 wb_stat_sum(struct bdi_writeback *wb, enum wb_stat_item item) |
e0bf68dd | 89 | { |
e3d3910a | 90 | return percpu_counter_sum_positive(&wb->stat[item]); |
e0bf68dd PZ |
91 | } |
92 | ||
93f78d88 | 93 | extern void wb_writeout_inc(struct bdi_writeback *wb); |
dd5656e5 | 94 | |
b2e8fb6e PZ |
95 | /* |
96 | * maximal error of a stat counter. | |
97 | */ | |
2bce774e | 98 | static inline unsigned long wb_stat_error(void) |
e0bf68dd | 99 | { |
b2e8fb6e | 100 | #ifdef CONFIG_SMP |
93f78d88 | 101 | return nr_cpu_ids * WB_STAT_BATCH; |
b2e8fb6e PZ |
102 | #else |
103 | return 1; | |
104 | #endif | |
e0bf68dd | 105 | } |
1da177e4 | 106 | |
189d3c4a | 107 | int bdi_set_min_ratio(struct backing_dev_info *bdi, unsigned int min_ratio); |
a42dde04 | 108 | int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ratio); |
189d3c4a | 109 | |
1da177e4 LT |
110 | /* |
111 | * Flags in backing_dev_info::capability | |
e4ad08fe | 112 | * |
f56753ac CH |
113 | * BDI_CAP_WRITEBACK: Supports dirty page writeback, and dirty pages |
114 | * should contribute to accounting | |
115 | * BDI_CAP_WRITEBACK_ACCT: Automatically account writeback pages | |
116 | * BDI_CAP_STRICTLIMIT: Keep number of dirty pages below bdi threshold | |
1da177e4 | 117 | */ |
f56753ac CH |
118 | #define BDI_CAP_WRITEBACK (1 << 0) |
119 | #define BDI_CAP_WRITEBACK_ACCT (1 << 1) | |
120 | #define BDI_CAP_STRICTLIMIT (1 << 2) | |
e4ad08fe | 121 | |
5129a469 | 122 | extern struct backing_dev_info noop_backing_dev_info; |
1da177e4 | 123 | |
bc05873d TH |
124 | /** |
125 | * writeback_in_progress - determine whether there is writeback in progress | |
126 | * @wb: bdi_writeback of interest | |
127 | * | |
128 | * Determine whether there is writeback waiting to be handled against a | |
129 | * bdi_writeback. | |
130 | */ | |
131 | static inline bool writeback_in_progress(struct bdi_writeback *wb) | |
1da177e4 | 132 | { |
bc05873d | 133 | return test_bit(WB_writeback_running, &wb->state); |
1da177e4 LT |
134 | } |
135 | ||
ccdf7741 | 136 | struct backing_dev_info *inode_to_bdi(struct inode *inode); |
1da177e4 | 137 | |
f56753ac | 138 | static inline bool mapping_can_writeback(struct address_space *mapping) |
e4ad08fe | 139 | { |
f56753ac | 140 | return inode_to_bdi(mapping->host)->capabilities & BDI_CAP_WRITEBACK; |
e4ad08fe | 141 | } |
1da177e4 | 142 | |
03ba3782 JA |
143 | static inline int bdi_sched_wait(void *word) |
144 | { | |
145 | schedule(); | |
146 | return 0; | |
147 | } | |
148 | ||
89e9b9e0 TH |
149 | #ifdef CONFIG_CGROUP_WRITEBACK |
150 | ||
ed288dc0 TH |
151 | struct bdi_writeback *wb_get_lookup(struct backing_dev_info *bdi, |
152 | struct cgroup_subsys_state *memcg_css); | |
52ebea74 TH |
153 | struct bdi_writeback *wb_get_create(struct backing_dev_info *bdi, |
154 | struct cgroup_subsys_state *memcg_css, | |
155 | gfp_t gfp); | |
52ebea74 TH |
156 | void wb_memcg_offline(struct mem_cgroup *memcg); |
157 | void wb_blkcg_offline(struct blkcg *blkcg); | |
158 | ||
89e9b9e0 TH |
159 | /** |
160 | * inode_cgwb_enabled - test whether cgroup writeback is enabled on an inode | |
161 | * @inode: inode of interest | |
162 | * | |
ed7b6b4f CH |
163 | * Cgroup writeback requires support from the filesystem. Also, both memcg and |
164 | * iocg have to be on the default hierarchy. Test whether all conditions are | |
165 | * met. | |
9badce00 TH |
166 | * |
167 | * Note that the test result may change dynamically on the same inode | |
168 | * depending on how memcg and iocg are configured. | |
89e9b9e0 TH |
169 | */ |
170 | static inline bool inode_cgwb_enabled(struct inode *inode) | |
171 | { | |
172 | struct backing_dev_info *bdi = inode_to_bdi(inode); | |
173 | ||
c0522908 TH |
174 | return cgroup_subsys_on_dfl(memory_cgrp_subsys) && |
175 | cgroup_subsys_on_dfl(io_cgrp_subsys) && | |
f56753ac | 176 | (bdi->capabilities & BDI_CAP_WRITEBACK) && |
46b15caa | 177 | (inode->i_sb->s_iflags & SB_I_CGROUPWB); |
89e9b9e0 TH |
178 | } |
179 | ||
52ebea74 TH |
180 | /** |
181 | * wb_find_current - find wb for %current on a bdi | |
182 | * @bdi: bdi of interest | |
183 | * | |
184 | * Find the wb of @bdi which matches both the memcg and blkcg of %current. | |
185 | * Must be called under rcu_read_lock() which protects the returend wb. | |
186 | * NULL if not found. | |
187 | */ | |
188 | static inline struct bdi_writeback *wb_find_current(struct backing_dev_info *bdi) | |
189 | { | |
190 | struct cgroup_subsys_state *memcg_css; | |
191 | struct bdi_writeback *wb; | |
192 | ||
193 | memcg_css = task_css(current, memory_cgrp_id); | |
194 | if (!memcg_css->parent) | |
195 | return &bdi->wb; | |
196 | ||
197 | wb = radix_tree_lookup(&bdi->cgwb_tree, memcg_css->id); | |
198 | ||
199 | /* | |
200 | * %current's blkcg equals the effective blkcg of its memcg. No | |
201 | * need to use the relatively expensive cgroup_get_e_css(). | |
202 | */ | |
c165b3e3 | 203 | if (likely(wb && wb->blkcg_css == task_css(current, io_cgrp_id))) |
52ebea74 TH |
204 | return wb; |
205 | return NULL; | |
206 | } | |
207 | ||
208 | /** | |
209 | * wb_get_create_current - get or create wb for %current on a bdi | |
210 | * @bdi: bdi of interest | |
211 | * @gfp: allocation mask | |
212 | * | |
213 | * Equivalent to wb_get_create() on %current's memcg. This function is | |
214 | * called from a relatively hot path and optimizes the common cases using | |
215 | * wb_find_current(). | |
216 | */ | |
217 | static inline struct bdi_writeback * | |
218 | wb_get_create_current(struct backing_dev_info *bdi, gfp_t gfp) | |
219 | { | |
220 | struct bdi_writeback *wb; | |
221 | ||
222 | rcu_read_lock(); | |
223 | wb = wb_find_current(bdi); | |
224 | if (wb && unlikely(!wb_tryget(wb))) | |
225 | wb = NULL; | |
226 | rcu_read_unlock(); | |
227 | ||
228 | if (unlikely(!wb)) { | |
229 | struct cgroup_subsys_state *memcg_css; | |
230 | ||
231 | memcg_css = task_get_css(current, memory_cgrp_id); | |
232 | wb = wb_get_create(bdi, memcg_css, gfp); | |
233 | css_put(memcg_css); | |
234 | } | |
235 | return wb; | |
236 | } | |
237 | ||
aaa2cacf TH |
238 | /** |
239 | * inode_to_wb_is_valid - test whether an inode has a wb associated | |
240 | * @inode: inode of interest | |
241 | * | |
242 | * Returns %true if @inode has a wb associated. May be called without any | |
243 | * locking. | |
244 | */ | |
245 | static inline bool inode_to_wb_is_valid(struct inode *inode) | |
246 | { | |
247 | return inode->i_wb; | |
248 | } | |
249 | ||
52ebea74 TH |
250 | /** |
251 | * inode_to_wb - determine the wb of an inode | |
252 | * @inode: inode of interest | |
253 | * | |
aaa2cacf | 254 | * Returns the wb @inode is currently associated with. The caller must be |
b93b0163 | 255 | * holding either @inode->i_lock, the i_pages lock, or the |
aaa2cacf | 256 | * associated wb's list_lock. |
52ebea74 | 257 | */ |
05b93801 | 258 | static inline struct bdi_writeback *inode_to_wb(const struct inode *inode) |
52ebea74 | 259 | { |
aaa2cacf TH |
260 | #ifdef CONFIG_LOCKDEP |
261 | WARN_ON_ONCE(debug_locks && | |
262 | (!lockdep_is_held(&inode->i_lock) && | |
b93b0163 | 263 | !lockdep_is_held(&inode->i_mapping->i_pages.xa_lock) && |
aaa2cacf TH |
264 | !lockdep_is_held(&inode->i_wb->list_lock))); |
265 | #endif | |
52ebea74 TH |
266 | return inode->i_wb; |
267 | } | |
268 | ||
fee468fd JK |
269 | static inline struct bdi_writeback *inode_to_wb_wbc( |
270 | struct inode *inode, | |
271 | struct writeback_control *wbc) | |
272 | { | |
273 | /* | |
274 | * If wbc does not have inode attached, it means cgroup writeback was | |
275 | * disabled when wbc started. Just use the default wb in that case. | |
276 | */ | |
277 | return wbc->wb ? wbc->wb : &inode_to_bdi(inode)->wb; | |
278 | } | |
279 | ||
682aa8e1 TH |
280 | /** |
281 | * unlocked_inode_to_wb_begin - begin unlocked inode wb access transaction | |
282 | * @inode: target inode | |
2e898e4c | 283 | * @cookie: output param, to be passed to the end function |
682aa8e1 TH |
284 | * |
285 | * The caller wants to access the wb associated with @inode but isn't | |
b93b0163 | 286 | * holding inode->i_lock, the i_pages lock or wb->list_lock. This |
682aa8e1 TH |
287 | * function determines the wb associated with @inode and ensures that the |
288 | * association doesn't change until the transaction is finished with | |
289 | * unlocked_inode_to_wb_end(). | |
290 | * | |
2e898e4c GT |
291 | * The caller must call unlocked_inode_to_wb_end() with *@cookie afterwards and |
292 | * can't sleep during the transaction. IRQs may or may not be disabled on | |
293 | * return. | |
682aa8e1 TH |
294 | */ |
295 | static inline struct bdi_writeback * | |
2e898e4c | 296 | unlocked_inode_to_wb_begin(struct inode *inode, struct wb_lock_cookie *cookie) |
682aa8e1 TH |
297 | { |
298 | rcu_read_lock(); | |
299 | ||
300 | /* | |
a9519def | 301 | * Paired with store_release in inode_switch_wbs_work_fn() and |
682aa8e1 TH |
302 | * ensures that we see the new wb if we see cleared I_WB_SWITCH. |
303 | */ | |
2e898e4c | 304 | cookie->locked = smp_load_acquire(&inode->i_state) & I_WB_SWITCH; |
682aa8e1 | 305 | |
2e898e4c GT |
306 | if (unlikely(cookie->locked)) |
307 | xa_lock_irqsave(&inode->i_mapping->i_pages, cookie->flags); | |
aaa2cacf TH |
308 | |
309 | /* | |
b93b0163 MW |
310 | * Protected by either !I_WB_SWITCH + rcu_read_lock() or the i_pages |
311 | * lock. inode_to_wb() will bark. Deref directly. | |
aaa2cacf TH |
312 | */ |
313 | return inode->i_wb; | |
682aa8e1 TH |
314 | } |
315 | ||
316 | /** | |
317 | * unlocked_inode_to_wb_end - end inode wb access transaction | |
318 | * @inode: target inode | |
2e898e4c | 319 | * @cookie: @cookie from unlocked_inode_to_wb_begin() |
682aa8e1 | 320 | */ |
2e898e4c GT |
321 | static inline void unlocked_inode_to_wb_end(struct inode *inode, |
322 | struct wb_lock_cookie *cookie) | |
682aa8e1 | 323 | { |
2e898e4c GT |
324 | if (unlikely(cookie->locked)) |
325 | xa_unlock_irqrestore(&inode->i_mapping->i_pages, cookie->flags); | |
682aa8e1 TH |
326 | |
327 | rcu_read_unlock(); | |
328 | } | |
329 | ||
89e9b9e0 TH |
330 | #else /* CONFIG_CGROUP_WRITEBACK */ |
331 | ||
332 | static inline bool inode_cgwb_enabled(struct inode *inode) | |
333 | { | |
334 | return false; | |
335 | } | |
336 | ||
52ebea74 TH |
337 | static inline struct bdi_writeback *wb_find_current(struct backing_dev_info *bdi) |
338 | { | |
339 | return &bdi->wb; | |
340 | } | |
341 | ||
342 | static inline struct bdi_writeback * | |
343 | wb_get_create_current(struct backing_dev_info *bdi, gfp_t gfp) | |
344 | { | |
345 | return &bdi->wb; | |
346 | } | |
347 | ||
aaa2cacf TH |
348 | static inline bool inode_to_wb_is_valid(struct inode *inode) |
349 | { | |
350 | return true; | |
351 | } | |
352 | ||
52ebea74 TH |
353 | static inline struct bdi_writeback *inode_to_wb(struct inode *inode) |
354 | { | |
355 | return &inode_to_bdi(inode)->wb; | |
356 | } | |
357 | ||
fee468fd JK |
358 | static inline struct bdi_writeback *inode_to_wb_wbc( |
359 | struct inode *inode, | |
360 | struct writeback_control *wbc) | |
361 | { | |
362 | return inode_to_wb(inode); | |
363 | } | |
364 | ||
365 | ||
682aa8e1 | 366 | static inline struct bdi_writeback * |
2e898e4c | 367 | unlocked_inode_to_wb_begin(struct inode *inode, struct wb_lock_cookie *cookie) |
682aa8e1 TH |
368 | { |
369 | return inode_to_wb(inode); | |
370 | } | |
371 | ||
2e898e4c GT |
372 | static inline void unlocked_inode_to_wb_end(struct inode *inode, |
373 | struct wb_lock_cookie *cookie) | |
682aa8e1 TH |
374 | { |
375 | } | |
376 | ||
52ebea74 TH |
377 | static inline void wb_memcg_offline(struct mem_cgroup *memcg) |
378 | { | |
379 | } | |
380 | ||
381 | static inline void wb_blkcg_offline(struct blkcg *blkcg) | |
382 | { | |
383 | } | |
384 | ||
89e9b9e0 TH |
385 | #endif /* CONFIG_CGROUP_WRITEBACK */ |
386 | ||
eb7ae5e0 | 387 | const char *bdi_dev_name(struct backing_dev_info *bdi); |
68f23b89 | 388 | |
89e9b9e0 | 389 | #endif /* _LINUX_BACKING_DEV_H */ |