Commit | Line | Data |
---|---|---|
457c8996 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
3fcfab16 | 2 | |
c97ab271 | 3 | #include <linux/blkdev.h> |
3fcfab16 | 4 | #include <linux/wait.h> |
34f8fe50 | 5 | #include <linux/rbtree.h> |
03ba3782 | 6 | #include <linux/kthread.h> |
e41d12f5 CH |
7 | #include <linux/backing-dev.h> |
8 | #include <linux/blk-cgroup.h> | |
03ba3782 | 9 | #include <linux/freezer.h> |
3fcfab16 | 10 | #include <linux/fs.h> |
26160158 | 11 | #include <linux/pagemap.h> |
03ba3782 | 12 | #include <linux/mm.h> |
c1ca59a1 | 13 | #include <linux/sched/mm.h> |
3fcfab16 AM |
14 | #include <linux/sched.h> |
15 | #include <linux/module.h> | |
cf0ca9fe PZ |
16 | #include <linux/writeback.h> |
17 | #include <linux/device.h> | |
455b2864 | 18 | #include <trace/events/writeback.h> |
cf0ca9fe | 19 | |
f56753ac | 20 | struct backing_dev_info noop_backing_dev_info; |
a212b105 | 21 | EXPORT_SYMBOL_GPL(noop_backing_dev_info); |
5129a469 | 22 | |
cf0ca9fe | 23 | static struct class *bdi_class; |
eb7ae5e0 | 24 | static const char *bdi_unknown_name = "(unknown)"; |
cfc4ba53 JA |
25 | |
26 | /* | |
34f8fe50 TH |
27 | * bdi_lock protects bdi_tree and updates to bdi_list. bdi_list has RCU |
28 | * reader side locking. | |
cfc4ba53 | 29 | */ |
03ba3782 | 30 | DEFINE_SPINLOCK(bdi_lock); |
34f8fe50 TH |
31 | static u64 bdi_id_cursor; |
32 | static struct rb_root bdi_tree = RB_ROOT; | |
66f3b8e2 | 33 | LIST_HEAD(bdi_list); |
03ba3782 | 34 | |
839a8e86 TH |
35 | /* bdi_wq serves all asynchronous writeback tasks */ |
36 | struct workqueue_struct *bdi_wq; | |
37 | ||
6986c3e2 BW |
38 | #define K(x) ((x) << (PAGE_SHIFT - 10)) |
39 | ||
76f1418b MS |
40 | #ifdef CONFIG_DEBUG_FS |
41 | #include <linux/debugfs.h> | |
42 | #include <linux/seq_file.h> | |
43 | ||
44 | static struct dentry *bdi_debug_root; | |
45 | ||
46 | static void bdi_debug_init(void) | |
47 | { | |
48 | bdi_debug_root = debugfs_create_dir("bdi", NULL); | |
49 | } | |
50 | ||
51 | static int bdi_debug_stats_show(struct seq_file *m, void *v) | |
52 | { | |
53 | struct backing_dev_info *bdi = m->private; | |
c1955ce3 | 54 | struct bdi_writeback *wb = &bdi->wb; |
364aeb28 DR |
55 | unsigned long background_thresh; |
56 | unsigned long dirty_thresh; | |
0d960a38 | 57 | unsigned long wb_thresh; |
0ae45f63 | 58 | unsigned long nr_dirty, nr_io, nr_more_io, nr_dirty_time; |
f09b00d3 JA |
59 | struct inode *inode; |
60 | ||
0ae45f63 | 61 | nr_dirty = nr_io = nr_more_io = nr_dirty_time = 0; |
f758eeab | 62 | spin_lock(&wb->list_lock); |
c7f54084 | 63 | list_for_each_entry(inode, &wb->b_dirty, i_io_list) |
c1955ce3 | 64 | nr_dirty++; |
c7f54084 | 65 | list_for_each_entry(inode, &wb->b_io, i_io_list) |
c1955ce3 | 66 | nr_io++; |
c7f54084 | 67 | list_for_each_entry(inode, &wb->b_more_io, i_io_list) |
c1955ce3 | 68 | nr_more_io++; |
c7f54084 | 69 | list_for_each_entry(inode, &wb->b_dirty_time, i_io_list) |
0ae45f63 TT |
70 | if (inode->i_state & I_DIRTY_TIME) |
71 | nr_dirty_time++; | |
f758eeab | 72 | spin_unlock(&wb->list_lock); |
76f1418b | 73 | |
16c4042f | 74 | global_dirty_limits(&background_thresh, &dirty_thresh); |
0d960a38 | 75 | wb_thresh = wb_calc_thresh(wb, dirty_thresh); |
76f1418b | 76 | |
76f1418b | 77 | seq_printf(m, |
00821b00 WF |
78 | "BdiWriteback: %10lu kB\n" |
79 | "BdiReclaimable: %10lu kB\n" | |
80 | "BdiDirtyThresh: %10lu kB\n" | |
81 | "DirtyThresh: %10lu kB\n" | |
82 | "BackgroundThresh: %10lu kB\n" | |
c8e28ce0 | 83 | "BdiDirtied: %10lu kB\n" |
00821b00 WF |
84 | "BdiWritten: %10lu kB\n" |
85 | "BdiWriteBandwidth: %10lu kBps\n" | |
86 | "b_dirty: %10lu\n" | |
87 | "b_io: %10lu\n" | |
88 | "b_more_io: %10lu\n" | |
0ae45f63 | 89 | "b_dirty_time: %10lu\n" |
00821b00 WF |
90 | "bdi_list: %10u\n" |
91 | "state: %10lx\n", | |
93f78d88 TH |
92 | (unsigned long) K(wb_stat(wb, WB_WRITEBACK)), |
93 | (unsigned long) K(wb_stat(wb, WB_RECLAIMABLE)), | |
0d960a38 | 94 | K(wb_thresh), |
f7d2b1ec JK |
95 | K(dirty_thresh), |
96 | K(background_thresh), | |
93f78d88 TH |
97 | (unsigned long) K(wb_stat(wb, WB_DIRTIED)), |
98 | (unsigned long) K(wb_stat(wb, WB_WRITTEN)), | |
a88a341a | 99 | (unsigned long) K(wb->write_bandwidth), |
f7d2b1ec JK |
100 | nr_dirty, |
101 | nr_io, | |
102 | nr_more_io, | |
0ae45f63 | 103 | nr_dirty_time, |
4452226e | 104 | !list_empty(&bdi->bdi_list), bdi->wb.state); |
76f1418b MS |
105 | |
106 | return 0; | |
107 | } | |
5ad35093 | 108 | DEFINE_SHOW_ATTRIBUTE(bdi_debug_stats); |
76f1418b | 109 | |
2d146b92 | 110 | static void bdi_debug_register(struct backing_dev_info *bdi, const char *name) |
76f1418b MS |
111 | { |
112 | bdi->debug_dir = debugfs_create_dir(name, bdi_debug_root); | |
97f07697 | 113 | |
2d146b92 GKH |
114 | debugfs_create_file("stats", 0444, bdi->debug_dir, bdi, |
115 | &bdi_debug_stats_fops); | |
76f1418b MS |
116 | } |
117 | ||
118 | static void bdi_debug_unregister(struct backing_dev_info *bdi) | |
119 | { | |
2d146b92 | 120 | debugfs_remove_recursive(bdi->debug_dir); |
76f1418b MS |
121 | } |
122 | #else | |
123 | static inline void bdi_debug_init(void) | |
124 | { | |
125 | } | |
2d146b92 | 126 | static inline void bdi_debug_register(struct backing_dev_info *bdi, |
76f1418b MS |
127 | const char *name) |
128 | { | |
129 | } | |
130 | static inline void bdi_debug_unregister(struct backing_dev_info *bdi) | |
131 | { | |
132 | } | |
133 | #endif | |
134 | ||
cf0ca9fe PZ |
135 | static ssize_t read_ahead_kb_store(struct device *dev, |
136 | struct device_attribute *attr, | |
137 | const char *buf, size_t count) | |
138 | { | |
139 | struct backing_dev_info *bdi = dev_get_drvdata(dev); | |
cf0ca9fe | 140 | unsigned long read_ahead_kb; |
7034ed13 | 141 | ssize_t ret; |
cf0ca9fe | 142 | |
7034ed13 NJ |
143 | ret = kstrtoul(buf, 10, &read_ahead_kb); |
144 | if (ret < 0) | |
145 | return ret; | |
146 | ||
147 | bdi->ra_pages = read_ahead_kb >> (PAGE_SHIFT - 10); | |
148 | ||
149 | return count; | |
cf0ca9fe PZ |
150 | } |
151 | ||
cf0ca9fe PZ |
152 | #define BDI_SHOW(name, expr) \ |
153 | static ssize_t name##_show(struct device *dev, \ | |
5e4c0d86 | 154 | struct device_attribute *attr, char *buf) \ |
cf0ca9fe PZ |
155 | { \ |
156 | struct backing_dev_info *bdi = dev_get_drvdata(dev); \ | |
157 | \ | |
5e4c0d86 | 158 | return sysfs_emit(buf, "%lld\n", (long long)expr); \ |
d9e1241e GKH |
159 | } \ |
160 | static DEVICE_ATTR_RW(name); | |
cf0ca9fe PZ |
161 | |
162 | BDI_SHOW(read_ahead_kb, K(bdi->ra_pages)) | |
163 | ||
189d3c4a PZ |
164 | static ssize_t min_ratio_store(struct device *dev, |
165 | struct device_attribute *attr, const char *buf, size_t count) | |
166 | { | |
167 | struct backing_dev_info *bdi = dev_get_drvdata(dev); | |
189d3c4a | 168 | unsigned int ratio; |
7034ed13 NJ |
169 | ssize_t ret; |
170 | ||
171 | ret = kstrtouint(buf, 10, &ratio); | |
172 | if (ret < 0) | |
173 | return ret; | |
174 | ||
175 | ret = bdi_set_min_ratio(bdi, ratio); | |
176 | if (!ret) | |
177 | ret = count; | |
189d3c4a | 178 | |
189d3c4a PZ |
179 | return ret; |
180 | } | |
181 | BDI_SHOW(min_ratio, bdi->min_ratio) | |
182 | ||
a42dde04 PZ |
183 | static ssize_t max_ratio_store(struct device *dev, |
184 | struct device_attribute *attr, const char *buf, size_t count) | |
185 | { | |
186 | struct backing_dev_info *bdi = dev_get_drvdata(dev); | |
a42dde04 | 187 | unsigned int ratio; |
7034ed13 NJ |
188 | ssize_t ret; |
189 | ||
190 | ret = kstrtouint(buf, 10, &ratio); | |
191 | if (ret < 0) | |
192 | return ret; | |
193 | ||
194 | ret = bdi_set_max_ratio(bdi, ratio); | |
195 | if (!ret) | |
196 | ret = count; | |
a42dde04 | 197 | |
a42dde04 PZ |
198 | return ret; |
199 | } | |
200 | BDI_SHOW(max_ratio, bdi->max_ratio) | |
201 | ||
7d311cda DW |
202 | static ssize_t stable_pages_required_show(struct device *dev, |
203 | struct device_attribute *attr, | |
5e4c0d86 | 204 | char *buf) |
7d311cda | 205 | { |
1cb039f3 CH |
206 | dev_warn_once(dev, |
207 | "the stable_pages_required attribute has been removed. Use the stable_writes queue attribute instead.\n"); | |
5e4c0d86 | 208 | return sysfs_emit(buf, "%d\n", 0); |
7d311cda | 209 | } |
d9e1241e GKH |
210 | static DEVICE_ATTR_RO(stable_pages_required); |
211 | ||
212 | static struct attribute *bdi_dev_attrs[] = { | |
213 | &dev_attr_read_ahead_kb.attr, | |
214 | &dev_attr_min_ratio.attr, | |
215 | &dev_attr_max_ratio.attr, | |
216 | &dev_attr_stable_pages_required.attr, | |
217 | NULL, | |
cf0ca9fe | 218 | }; |
d9e1241e | 219 | ATTRIBUTE_GROUPS(bdi_dev); |
cf0ca9fe PZ |
220 | |
221 | static __init int bdi_class_init(void) | |
222 | { | |
223 | bdi_class = class_create(THIS_MODULE, "bdi"); | |
14421453 AB |
224 | if (IS_ERR(bdi_class)) |
225 | return PTR_ERR(bdi_class); | |
226 | ||
d9e1241e | 227 | bdi_class->dev_groups = bdi_dev_groups; |
76f1418b | 228 | bdi_debug_init(); |
d03f6cdc | 229 | |
cf0ca9fe PZ |
230 | return 0; |
231 | } | |
76f1418b | 232 | postcore_initcall(bdi_class_init); |
cf0ca9fe | 233 | |
26160158 JA |
234 | static int __init default_bdi_init(void) |
235 | { | |
a2b90f11 MW |
236 | bdi_wq = alloc_workqueue("writeback", WQ_MEM_RECLAIM | WQ_UNBOUND | |
237 | WQ_SYSFS, 0); | |
839a8e86 TH |
238 | if (!bdi_wq) |
239 | return -ENOMEM; | |
4bca7e80 | 240 | return 0; |
26160158 JA |
241 | } |
242 | subsys_initcall(default_bdi_init); | |
243 | ||
6467716a | 244 | /* |
f0054bb1 | 245 | * This function is used when the first inode for this wb is marked dirty. It |
6467716a AB |
246 | * wakes-up the corresponding bdi thread which should then take care of the |
247 | * periodic background write-out of dirty inodes. Since the write-out would | |
248 | * starts only 'dirty_writeback_interval' centisecs from now anyway, we just | |
249 | * set up a timer which wakes the bdi thread up later. | |
250 | * | |
251 | * Note, we wouldn't bother setting up the timer, but this function is on the | |
252 | * fast-path (used by '__mark_inode_dirty()'), so we save few context switches | |
253 | * by delaying the wake-up. | |
6ca738d6 DB |
254 | * |
255 | * We have to be careful not to postpone flush work if it is scheduled for | |
256 | * earlier. Thus we use queue_delayed_work(). | |
6467716a | 257 | */ |
f0054bb1 | 258 | void wb_wakeup_delayed(struct bdi_writeback *wb) |
6467716a AB |
259 | { |
260 | unsigned long timeout; | |
261 | ||
262 | timeout = msecs_to_jiffies(dirty_writeback_interval * 10); | |
f87904c0 | 263 | spin_lock_irq(&wb->work_lock); |
f0054bb1 TH |
264 | if (test_bit(WB_registered, &wb->state)) |
265 | queue_delayed_work(bdi_wq, &wb->dwork, timeout); | |
f87904c0 | 266 | spin_unlock_irq(&wb->work_lock); |
03ba3782 JA |
267 | } |
268 | ||
45a2966f JK |
269 | static void wb_update_bandwidth_workfn(struct work_struct *work) |
270 | { | |
271 | struct bdi_writeback *wb = container_of(to_delayed_work(work), | |
272 | struct bdi_writeback, bw_dwork); | |
273 | ||
274 | wb_update_bandwidth(wb); | |
275 | } | |
276 | ||
cfc4ba53 | 277 | /* |
a88a341a | 278 | * Initial write bandwidth: 100 MB/s |
cfc4ba53 | 279 | */ |
a88a341a | 280 | #define INIT_BW (100 << (20 - PAGE_SHIFT)) |
cfc4ba53 | 281 | |
8395cd9f | 282 | static int wb_init(struct bdi_writeback *wb, struct backing_dev_info *bdi, |
8c911f3d | 283 | gfp_t gfp) |
cf0ca9fe | 284 | { |
93f78d88 | 285 | int i, err; |
cf0ca9fe | 286 | |
6467716a | 287 | memset(wb, 0, sizeof(*wb)); |
f1d0b063 | 288 | |
6467716a AB |
289 | wb->bdi = bdi; |
290 | wb->last_old_flush = jiffies; | |
291 | INIT_LIST_HEAD(&wb->b_dirty); | |
292 | INIT_LIST_HEAD(&wb->b_io); | |
293 | INIT_LIST_HEAD(&wb->b_more_io); | |
0ae45f63 | 294 | INIT_LIST_HEAD(&wb->b_dirty_time); |
f758eeab | 295 | spin_lock_init(&wb->list_lock); |
66f3b8e2 | 296 | |
633a2abb | 297 | atomic_set(&wb->writeback_inodes, 0); |
a88a341a TH |
298 | wb->bw_time_stamp = jiffies; |
299 | wb->balanced_dirty_ratelimit = INIT_BW; | |
300 | wb->dirty_ratelimit = INIT_BW; | |
301 | wb->write_bandwidth = INIT_BW; | |
302 | wb->avg_write_bandwidth = INIT_BW; | |
cf0ca9fe | 303 | |
f0054bb1 TH |
304 | spin_lock_init(&wb->work_lock); |
305 | INIT_LIST_HEAD(&wb->work_list); | |
306 | INIT_DELAYED_WORK(&wb->dwork, wb_workfn); | |
45a2966f | 307 | INIT_DELAYED_WORK(&wb->bw_dwork, wb_update_bandwidth_workfn); |
b57d74af | 308 | wb->dirty_sleep = jiffies; |
c284de61 | 309 | |
8395cd9f | 310 | err = fprop_local_init_percpu(&wb->completions, gfp); |
a88a341a | 311 | if (err) |
efee1713 | 312 | return err; |
c284de61 | 313 | |
93f78d88 | 314 | for (i = 0; i < NR_WB_STAT_ITEMS; i++) { |
8395cd9f | 315 | err = percpu_counter_init(&wb->stat[i], 0, gfp); |
a13f35e8 TH |
316 | if (err) |
317 | goto out_destroy_stat; | |
93f78d88 | 318 | } |
cf0ca9fe | 319 | |
93f78d88 | 320 | return 0; |
a13f35e8 TH |
321 | |
322 | out_destroy_stat: | |
078c6c3a | 323 | while (i--) |
a13f35e8 TH |
324 | percpu_counter_destroy(&wb->stat[i]); |
325 | fprop_local_destroy_percpu(&wb->completions); | |
a13f35e8 | 326 | return err; |
cf0ca9fe | 327 | } |
cf0ca9fe | 328 | |
e8cb72b3 JK |
329 | static void cgwb_remove_from_bdi_list(struct bdi_writeback *wb); |
330 | ||
03ba3782 JA |
331 | /* |
332 | * Remove bdi from the global list and shutdown any threads we have running | |
333 | */ | |
46100071 | 334 | static void wb_shutdown(struct bdi_writeback *wb) |
66f3b8e2 | 335 | { |
c4db59d3 | 336 | /* Make sure nobody queues further work */ |
f87904c0 | 337 | spin_lock_irq(&wb->work_lock); |
46100071 | 338 | if (!test_and_clear_bit(WB_registered, &wb->state)) { |
f87904c0 | 339 | spin_unlock_irq(&wb->work_lock); |
03ba3782 | 340 | return; |
c4db59d3 | 341 | } |
f87904c0 | 342 | spin_unlock_irq(&wb->work_lock); |
03ba3782 | 343 | |
e8cb72b3 | 344 | cgwb_remove_from_bdi_list(wb); |
03ba3782 | 345 | /* |
46100071 TH |
346 | * Drain work list and shutdown the delayed_work. !WB_registered |
347 | * tells wb_workfn() that @wb is dying and its work_list needs to | |
348 | * be drained no matter what. | |
03ba3782 | 349 | */ |
46100071 TH |
350 | mod_delayed_work(bdi_wq, &wb->dwork, 0); |
351 | flush_delayed_work(&wb->dwork); | |
352 | WARN_ON(!list_empty(&wb->work_list)); | |
45a2966f | 353 | flush_delayed_work(&wb->bw_dwork); |
46100071 TH |
354 | } |
355 | ||
f0054bb1 | 356 | static void wb_exit(struct bdi_writeback *wb) |
93f78d88 TH |
357 | { |
358 | int i; | |
359 | ||
360 | WARN_ON(delayed_work_pending(&wb->dwork)); | |
361 | ||
362 | for (i = 0; i < NR_WB_STAT_ITEMS; i++) | |
363 | percpu_counter_destroy(&wb->stat[i]); | |
6467716a | 364 | |
a88a341a TH |
365 | fprop_local_destroy_percpu(&wb->completions); |
366 | } | |
e98be2d5 | 367 | |
52ebea74 TH |
368 | #ifdef CONFIG_CGROUP_WRITEBACK |
369 | ||
370 | #include <linux/memcontrol.h> | |
371 | ||
372 | /* | |
c22d70a1 RG |
373 | * cgwb_lock protects bdi->cgwb_tree, blkcg->cgwb_list, offline_cgwbs and |
374 | * memcg->cgwb_list. bdi->cgwb_tree is also RCU protected. | |
52ebea74 TH |
375 | */ |
376 | static DEFINE_SPINLOCK(cgwb_lock); | |
f1834646 | 377 | static struct workqueue_struct *cgwb_release_wq; |
52ebea74 | 378 | |
c22d70a1 RG |
379 | static LIST_HEAD(offline_cgwbs); |
380 | static void cleanup_offline_cgwbs_workfn(struct work_struct *work); | |
381 | static DECLARE_WORK(cleanup_offline_cgwbs_work, cleanup_offline_cgwbs_workfn); | |
382 | ||
52ebea74 TH |
383 | static void cgwb_release_workfn(struct work_struct *work) |
384 | { | |
385 | struct bdi_writeback *wb = container_of(work, struct bdi_writeback, | |
386 | release_work); | |
efee1713 | 387 | struct backing_dev_info *bdi = wb->bdi; |
52ebea74 | 388 | |
3ee7e869 | 389 | mutex_lock(&wb->bdi->cgwb_release_mutex); |
52ebea74 TH |
390 | wb_shutdown(wb); |
391 | ||
392 | css_put(wb->memcg_css); | |
393 | css_put(wb->blkcg_css); | |
3ee7e869 | 394 | mutex_unlock(&wb->bdi->cgwb_release_mutex); |
52ebea74 | 395 | |
d866dbf6 | 396 | /* triggers blkg destruction if no online users left */ |
397c9f46 | 397 | blkcg_unpin_online(wb->blkcg_css); |
59b57717 | 398 | |
841710aa | 399 | fprop_local_destroy_percpu(&wb->memcg_completions); |
c22d70a1 RG |
400 | |
401 | spin_lock_irq(&cgwb_lock); | |
402 | list_del(&wb->offline_node); | |
403 | spin_unlock_irq(&cgwb_lock); | |
404 | ||
b43a9e76 | 405 | percpu_ref_exit(&wb->refcnt); |
52ebea74 | 406 | wb_exit(wb); |
efee1713 | 407 | bdi_put(bdi); |
f3b6a6df | 408 | WARN_ON_ONCE(!list_empty(&wb->b_attached)); |
52ebea74 | 409 | kfree_rcu(wb, rcu); |
52ebea74 TH |
410 | } |
411 | ||
412 | static void cgwb_release(struct percpu_ref *refcnt) | |
413 | { | |
414 | struct bdi_writeback *wb = container_of(refcnt, struct bdi_writeback, | |
415 | refcnt); | |
f1834646 | 416 | queue_work(cgwb_release_wq, &wb->release_work); |
52ebea74 TH |
417 | } |
418 | ||
419 | static void cgwb_kill(struct bdi_writeback *wb) | |
420 | { | |
421 | lockdep_assert_held(&cgwb_lock); | |
422 | ||
423 | WARN_ON(!radix_tree_delete(&wb->bdi->cgwb_tree, wb->memcg_css->id)); | |
424 | list_del(&wb->memcg_node); | |
425 | list_del(&wb->blkcg_node); | |
c22d70a1 | 426 | list_add(&wb->offline_node, &offline_cgwbs); |
52ebea74 TH |
427 | percpu_ref_kill(&wb->refcnt); |
428 | } | |
429 | ||
e8cb72b3 JK |
430 | static void cgwb_remove_from_bdi_list(struct bdi_writeback *wb) |
431 | { | |
432 | spin_lock_irq(&cgwb_lock); | |
433 | list_del_rcu(&wb->bdi_node); | |
434 | spin_unlock_irq(&cgwb_lock); | |
435 | } | |
436 | ||
52ebea74 TH |
437 | static int cgwb_create(struct backing_dev_info *bdi, |
438 | struct cgroup_subsys_state *memcg_css, gfp_t gfp) | |
439 | { | |
440 | struct mem_cgroup *memcg; | |
441 | struct cgroup_subsys_state *blkcg_css; | |
52ebea74 TH |
442 | struct list_head *memcg_cgwb_list, *blkcg_cgwb_list; |
443 | struct bdi_writeback *wb; | |
444 | unsigned long flags; | |
445 | int ret = 0; | |
446 | ||
447 | memcg = mem_cgroup_from_css(memcg_css); | |
c165b3e3 | 448 | blkcg_css = cgroup_get_e_css(memcg_css->cgroup, &io_cgrp_subsys); |
9ccc3617 | 449 | memcg_cgwb_list = &memcg->cgwb_list; |
dec223c9 | 450 | blkcg_cgwb_list = blkcg_get_cgwb_list(blkcg_css); |
52ebea74 TH |
451 | |
452 | /* look up again under lock and discard on blkcg mismatch */ | |
453 | spin_lock_irqsave(&cgwb_lock, flags); | |
454 | wb = radix_tree_lookup(&bdi->cgwb_tree, memcg_css->id); | |
455 | if (wb && wb->blkcg_css != blkcg_css) { | |
456 | cgwb_kill(wb); | |
457 | wb = NULL; | |
458 | } | |
459 | spin_unlock_irqrestore(&cgwb_lock, flags); | |
460 | if (wb) | |
461 | goto out_put; | |
462 | ||
463 | /* need to create a new one */ | |
464 | wb = kmalloc(sizeof(*wb), gfp); | |
0b045bd1 CJ |
465 | if (!wb) { |
466 | ret = -ENOMEM; | |
467 | goto out_put; | |
468 | } | |
52ebea74 | 469 | |
8c911f3d | 470 | ret = wb_init(wb, bdi, gfp); |
52ebea74 TH |
471 | if (ret) |
472 | goto err_free; | |
473 | ||
474 | ret = percpu_ref_init(&wb->refcnt, cgwb_release, 0, gfp); | |
475 | if (ret) | |
476 | goto err_wb_exit; | |
477 | ||
841710aa TH |
478 | ret = fprop_local_init_percpu(&wb->memcg_completions, gfp); |
479 | if (ret) | |
480 | goto err_ref_exit; | |
481 | ||
52ebea74 TH |
482 | wb->memcg_css = memcg_css; |
483 | wb->blkcg_css = blkcg_css; | |
f3b6a6df | 484 | INIT_LIST_HEAD(&wb->b_attached); |
52ebea74 TH |
485 | INIT_WORK(&wb->release_work, cgwb_release_workfn); |
486 | set_bit(WB_registered, &wb->state); | |
efee1713 | 487 | bdi_get(bdi); |
03ba3782 JA |
488 | |
489 | /* | |
52ebea74 TH |
490 | * The root wb determines the registered state of the whole bdi and |
491 | * memcg_cgwb_list and blkcg_cgwb_list's next pointers indicate | |
492 | * whether they're still online. Don't link @wb if any is dead. | |
493 | * See wb_memcg_offline() and wb_blkcg_offline(). | |
03ba3782 | 494 | */ |
52ebea74 TH |
495 | ret = -ENODEV; |
496 | spin_lock_irqsave(&cgwb_lock, flags); | |
497 | if (test_bit(WB_registered, &bdi->wb.state) && | |
498 | blkcg_cgwb_list->next && memcg_cgwb_list->next) { | |
499 | /* we might have raced another instance of this function */ | |
500 | ret = radix_tree_insert(&bdi->cgwb_tree, memcg_css->id, wb); | |
501 | if (!ret) { | |
b817525a | 502 | list_add_tail_rcu(&wb->bdi_node, &bdi->wb_list); |
52ebea74 TH |
503 | list_add(&wb->memcg_node, memcg_cgwb_list); |
504 | list_add(&wb->blkcg_node, blkcg_cgwb_list); | |
397c9f46 | 505 | blkcg_pin_online(blkcg_css); |
52ebea74 TH |
506 | css_get(memcg_css); |
507 | css_get(blkcg_css); | |
508 | } | |
509 | } | |
510 | spin_unlock_irqrestore(&cgwb_lock, flags); | |
511 | if (ret) { | |
512 | if (ret == -EEXIST) | |
513 | ret = 0; | |
a13f35e8 | 514 | goto err_fprop_exit; |
52ebea74 TH |
515 | } |
516 | goto out_put; | |
517 | ||
841710aa | 518 | err_fprop_exit: |
efee1713 | 519 | bdi_put(bdi); |
841710aa | 520 | fprop_local_destroy_percpu(&wb->memcg_completions); |
52ebea74 TH |
521 | err_ref_exit: |
522 | percpu_ref_exit(&wb->refcnt); | |
523 | err_wb_exit: | |
524 | wb_exit(wb); | |
525 | err_free: | |
526 | kfree(wb); | |
527 | out_put: | |
528 | css_put(blkcg_css); | |
529 | return ret; | |
66f3b8e2 JA |
530 | } |
531 | ||
52ebea74 | 532 | /** |
ed288dc0 | 533 | * wb_get_lookup - get wb for a given memcg |
52ebea74 TH |
534 | * @bdi: target bdi |
535 | * @memcg_css: cgroup_subsys_state of the target memcg (must have positive ref) | |
52ebea74 | 536 | * |
ed288dc0 TH |
537 | * Try to get the wb for @memcg_css on @bdi. The returned wb has its |
538 | * refcount incremented. | |
52ebea74 TH |
539 | * |
540 | * This function uses css_get() on @memcg_css and thus expects its refcnt | |
541 | * to be positive on invocation. IOW, rcu_read_lock() protection on | |
542 | * @memcg_css isn't enough. try_get it before calling this function. | |
543 | * | |
544 | * A wb is keyed by its associated memcg. As blkcg implicitly enables | |
545 | * memcg on the default hierarchy, memcg association is guaranteed to be | |
546 | * more specific (equal or descendant to the associated blkcg) and thus can | |
547 | * identify both the memcg and blkcg associations. | |
548 | * | |
549 | * Because the blkcg associated with a memcg may change as blkcg is enabled | |
550 | * and disabled closer to root in the hierarchy, each wb keeps track of | |
551 | * both the memcg and blkcg associated with it and verifies the blkcg on | |
552 | * each lookup. On mismatch, the existing wb is discarded and a new one is | |
553 | * created. | |
554 | */ | |
ed288dc0 TH |
555 | struct bdi_writeback *wb_get_lookup(struct backing_dev_info *bdi, |
556 | struct cgroup_subsys_state *memcg_css) | |
557 | { | |
558 | struct bdi_writeback *wb; | |
559 | ||
560 | if (!memcg_css->parent) | |
561 | return &bdi->wb; | |
562 | ||
563 | rcu_read_lock(); | |
564 | wb = radix_tree_lookup(&bdi->cgwb_tree, memcg_css->id); | |
565 | if (wb) { | |
566 | struct cgroup_subsys_state *blkcg_css; | |
567 | ||
568 | /* see whether the blkcg association has changed */ | |
569 | blkcg_css = cgroup_get_e_css(memcg_css->cgroup, &io_cgrp_subsys); | |
570 | if (unlikely(wb->blkcg_css != blkcg_css || !wb_tryget(wb))) | |
571 | wb = NULL; | |
572 | css_put(blkcg_css); | |
573 | } | |
574 | rcu_read_unlock(); | |
575 | ||
576 | return wb; | |
577 | } | |
578 | ||
579 | /** | |
580 | * wb_get_create - get wb for a given memcg, create if necessary | |
581 | * @bdi: target bdi | |
582 | * @memcg_css: cgroup_subsys_state of the target memcg (must have positive ref) | |
583 | * @gfp: allocation mask to use | |
584 | * | |
585 | * Try to get the wb for @memcg_css on @bdi. If it doesn't exist, try to | |
586 | * create one. See wb_get_lookup() for more details. | |
587 | */ | |
52ebea74 TH |
588 | struct bdi_writeback *wb_get_create(struct backing_dev_info *bdi, |
589 | struct cgroup_subsys_state *memcg_css, | |
590 | gfp_t gfp) | |
6467716a | 591 | { |
52ebea74 TH |
592 | struct bdi_writeback *wb; |
593 | ||
c1ca59a1 | 594 | might_alloc(gfp); |
52ebea74 TH |
595 | |
596 | if (!memcg_css->parent) | |
597 | return &bdi->wb; | |
598 | ||
599 | do { | |
ed288dc0 | 600 | wb = wb_get_lookup(bdi, memcg_css); |
52ebea74 TH |
601 | } while (!wb && !cgwb_create(bdi, memcg_css, gfp)); |
602 | ||
603 | return wb; | |
604 | } | |
6467716a | 605 | |
a13f35e8 | 606 | static int cgwb_bdi_init(struct backing_dev_info *bdi) |
52ebea74 | 607 | { |
a13f35e8 TH |
608 | int ret; |
609 | ||
52ebea74 | 610 | INIT_RADIX_TREE(&bdi->cgwb_tree, GFP_ATOMIC); |
3ee7e869 | 611 | mutex_init(&bdi->cgwb_release_mutex); |
7fc5854f | 612 | init_rwsem(&bdi->wb_switch_rwsem); |
a13f35e8 | 613 | |
8c911f3d | 614 | ret = wb_init(&bdi->wb, bdi, GFP_KERNEL); |
a13f35e8 | 615 | if (!ret) { |
7d828602 | 616 | bdi->wb.memcg_css = &root_mem_cgroup->css; |
a13f35e8 TH |
617 | bdi->wb.blkcg_css = blkcg_root_css; |
618 | } | |
619 | return ret; | |
6467716a AB |
620 | } |
621 | ||
b1c51afc | 622 | static void cgwb_bdi_unregister(struct backing_dev_info *bdi) |
52ebea74 TH |
623 | { |
624 | struct radix_tree_iter iter; | |
625 | void **slot; | |
5318ce7d | 626 | struct bdi_writeback *wb; |
52ebea74 TH |
627 | |
628 | WARN_ON(test_bit(WB_registered, &bdi->wb.state)); | |
629 | ||
630 | spin_lock_irq(&cgwb_lock); | |
631 | radix_tree_for_each_slot(slot, &bdi->cgwb_tree, &iter, 0) | |
632 | cgwb_kill(*slot); | |
3ee7e869 | 633 | spin_unlock_irq(&cgwb_lock); |
5318ce7d | 634 | |
3ee7e869 JK |
635 | mutex_lock(&bdi->cgwb_release_mutex); |
636 | spin_lock_irq(&cgwb_lock); | |
5318ce7d JK |
637 | while (!list_empty(&bdi->wb_list)) { |
638 | wb = list_first_entry(&bdi->wb_list, struct bdi_writeback, | |
639 | bdi_node); | |
640 | spin_unlock_irq(&cgwb_lock); | |
641 | wb_shutdown(wb); | |
642 | spin_lock_irq(&cgwb_lock); | |
643 | } | |
52ebea74 | 644 | spin_unlock_irq(&cgwb_lock); |
3ee7e869 | 645 | mutex_unlock(&bdi->cgwb_release_mutex); |
52ebea74 TH |
646 | } |
647 | ||
c22d70a1 RG |
648 | /* |
649 | * cleanup_offline_cgwbs_workfn - try to release dying cgwbs | |
650 | * | |
651 | * Try to release dying cgwbs by switching attached inodes to the nearest | |
652 | * living ancestor's writeback. Processed wbs are placed at the end | |
653 | * of the list to guarantee the forward progress. | |
654 | */ | |
655 | static void cleanup_offline_cgwbs_workfn(struct work_struct *work) | |
656 | { | |
657 | struct bdi_writeback *wb; | |
658 | LIST_HEAD(processed); | |
659 | ||
660 | spin_lock_irq(&cgwb_lock); | |
661 | ||
662 | while (!list_empty(&offline_cgwbs)) { | |
663 | wb = list_first_entry(&offline_cgwbs, struct bdi_writeback, | |
664 | offline_node); | |
665 | list_move(&wb->offline_node, &processed); | |
666 | ||
667 | /* | |
668 | * If wb is dirty, cleaning up the writeback by switching | |
669 | * attached inodes will result in an effective removal of any | |
670 | * bandwidth restrictions, which isn't the goal. Instead, | |
671 | * it can be postponed until the next time, when all io | |
672 | * will be likely completed. If in the meantime some inodes | |
673 | * will get re-dirtied, they should be eventually switched to | |
674 | * a new cgwb. | |
675 | */ | |
676 | if (wb_has_dirty_io(wb)) | |
677 | continue; | |
678 | ||
679 | if (!wb_tryget(wb)) | |
680 | continue; | |
681 | ||
682 | spin_unlock_irq(&cgwb_lock); | |
683 | while (cleanup_offline_cgwb(wb)) | |
684 | cond_resched(); | |
685 | spin_lock_irq(&cgwb_lock); | |
686 | ||
687 | wb_put(wb); | |
688 | } | |
689 | ||
690 | if (!list_empty(&processed)) | |
691 | list_splice_tail(&processed, &offline_cgwbs); | |
692 | ||
693 | spin_unlock_irq(&cgwb_lock); | |
694 | } | |
695 | ||
52ebea74 TH |
696 | /** |
697 | * wb_memcg_offline - kill all wb's associated with a memcg being offlined | |
698 | * @memcg: memcg being offlined | |
699 | * | |
700 | * Also prevents creation of any new wb's associated with @memcg. | |
e98be2d5 | 701 | */ |
52ebea74 TH |
702 | void wb_memcg_offline(struct mem_cgroup *memcg) |
703 | { | |
9ccc3617 | 704 | struct list_head *memcg_cgwb_list = &memcg->cgwb_list; |
52ebea74 TH |
705 | struct bdi_writeback *wb, *next; |
706 | ||
707 | spin_lock_irq(&cgwb_lock); | |
708 | list_for_each_entry_safe(wb, next, memcg_cgwb_list, memcg_node) | |
709 | cgwb_kill(wb); | |
710 | memcg_cgwb_list->next = NULL; /* prevent new wb's */ | |
711 | spin_unlock_irq(&cgwb_lock); | |
c22d70a1 RG |
712 | |
713 | queue_work(system_unbound_wq, &cleanup_offline_cgwbs_work); | |
52ebea74 TH |
714 | } |
715 | ||
716 | /** | |
717 | * wb_blkcg_offline - kill all wb's associated with a blkcg being offlined | |
dec223c9 | 718 | * @css: blkcg being offlined |
52ebea74 TH |
719 | * |
720 | * Also prevents creation of any new wb's associated with @blkcg. | |
721 | */ | |
dec223c9 | 722 | void wb_blkcg_offline(struct cgroup_subsys_state *css) |
52ebea74 | 723 | { |
52ebea74 | 724 | struct bdi_writeback *wb, *next; |
dec223c9 | 725 | struct list_head *list = blkcg_get_cgwb_list(css); |
52ebea74 TH |
726 | |
727 | spin_lock_irq(&cgwb_lock); | |
dec223c9 | 728 | list_for_each_entry_safe(wb, next, list, blkcg_node) |
52ebea74 | 729 | cgwb_kill(wb); |
dec223c9 | 730 | list->next = NULL; /* prevent new wb's */ |
52ebea74 TH |
731 | spin_unlock_irq(&cgwb_lock); |
732 | } | |
733 | ||
e8cb72b3 JK |
734 | static void cgwb_bdi_register(struct backing_dev_info *bdi) |
735 | { | |
736 | spin_lock_irq(&cgwb_lock); | |
737 | list_add_tail_rcu(&bdi->wb.bdi_node, &bdi->wb_list); | |
738 | spin_unlock_irq(&cgwb_lock); | |
739 | } | |
740 | ||
f1834646 TH |
741 | static int __init cgwb_init(void) |
742 | { | |
743 | /* | |
744 | * There can be many concurrent release work items overwhelming | |
745 | * system_wq. Put them in a separate wq and limit concurrency. | |
746 | * There's no point in executing many of these in parallel. | |
747 | */ | |
748 | cgwb_release_wq = alloc_workqueue("cgwb_release", 0, 1); | |
749 | if (!cgwb_release_wq) | |
750 | return -ENOMEM; | |
751 | ||
752 | return 0; | |
753 | } | |
754 | subsys_initcall(cgwb_init); | |
755 | ||
52ebea74 TH |
756 | #else /* CONFIG_CGROUP_WRITEBACK */ |
757 | ||
a13f35e8 TH |
758 | static int cgwb_bdi_init(struct backing_dev_info *bdi) |
759 | { | |
8c911f3d | 760 | return wb_init(&bdi->wb, bdi, GFP_KERNEL); |
a13f35e8 TH |
761 | } |
762 | ||
b1c51afc | 763 | static void cgwb_bdi_unregister(struct backing_dev_info *bdi) { } |
df23de55 | 764 | |
e8cb72b3 JK |
765 | static void cgwb_bdi_register(struct backing_dev_info *bdi) |
766 | { | |
767 | list_add_tail_rcu(&bdi->wb.bdi_node, &bdi->wb_list); | |
768 | } | |
769 | ||
770 | static void cgwb_remove_from_bdi_list(struct bdi_writeback *wb) | |
771 | { | |
772 | list_del_rcu(&wb->bdi_node); | |
773 | } | |
774 | ||
52ebea74 | 775 | #endif /* CONFIG_CGROUP_WRITEBACK */ |
e98be2d5 | 776 | |
4bca7e80 | 777 | int bdi_init(struct backing_dev_info *bdi) |
b2e8fb6e | 778 | { |
cf0ca9fe PZ |
779 | bdi->dev = NULL; |
780 | ||
d03f6cdc | 781 | kref_init(&bdi->refcnt); |
189d3c4a | 782 | bdi->min_ratio = 0; |
a42dde04 | 783 | bdi->max_ratio = 100; |
eb608e3a | 784 | bdi->max_prop_frac = FPROP_FRAC_BASE; |
66f3b8e2 | 785 | INIT_LIST_HEAD(&bdi->bdi_list); |
b817525a | 786 | INIT_LIST_HEAD(&bdi->wb_list); |
cc395d7f | 787 | init_waitqueue_head(&bdi->wb_waitq); |
03ba3782 | 788 | |
3083da7b | 789 | return cgwb_bdi_init(bdi); |
b2e8fb6e | 790 | } |
e98be2d5 | 791 | |
aef33c2f | 792 | struct backing_dev_info *bdi_alloc(int node_id) |
d03f6cdc JK |
793 | { |
794 | struct backing_dev_info *bdi; | |
795 | ||
aef33c2f | 796 | bdi = kzalloc_node(sizeof(*bdi), GFP_KERNEL, node_id); |
d03f6cdc JK |
797 | if (!bdi) |
798 | return NULL; | |
799 | ||
800 | if (bdi_init(bdi)) { | |
801 | kfree(bdi); | |
802 | return NULL; | |
803 | } | |
f56753ac | 804 | bdi->capabilities = BDI_CAP_WRITEBACK | BDI_CAP_WRITEBACK_ACCT; |
55b2598e CH |
805 | bdi->ra_pages = VM_READAHEAD_PAGES; |
806 | bdi->io_pages = VM_READAHEAD_PAGES; | |
5ed964f8 | 807 | timer_setup(&bdi->laptop_mode_wb_timer, laptop_mode_timer_fn, 0); |
d03f6cdc JK |
808 | return bdi; |
809 | } | |
aef33c2f | 810 | EXPORT_SYMBOL(bdi_alloc); |
d03f6cdc | 811 | |
34f8fe50 TH |
812 | static struct rb_node **bdi_lookup_rb_node(u64 id, struct rb_node **parentp) |
813 | { | |
814 | struct rb_node **p = &bdi_tree.rb_node; | |
815 | struct rb_node *parent = NULL; | |
816 | struct backing_dev_info *bdi; | |
817 | ||
818 | lockdep_assert_held(&bdi_lock); | |
819 | ||
820 | while (*p) { | |
821 | parent = *p; | |
822 | bdi = rb_entry(parent, struct backing_dev_info, rb_node); | |
823 | ||
824 | if (bdi->id > id) | |
825 | p = &(*p)->rb_left; | |
826 | else if (bdi->id < id) | |
827 | p = &(*p)->rb_right; | |
828 | else | |
829 | break; | |
830 | } | |
831 | ||
832 | if (parentp) | |
833 | *parentp = parent; | |
834 | return p; | |
835 | } | |
836 | ||
837 | /** | |
838 | * bdi_get_by_id - lookup and get bdi from its id | |
839 | * @id: bdi id to lookup | |
840 | * | |
841 | * Find bdi matching @id and get it. Returns NULL if the matching bdi | |
842 | * doesn't exist or is already unregistered. | |
843 | */ | |
844 | struct backing_dev_info *bdi_get_by_id(u64 id) | |
845 | { | |
846 | struct backing_dev_info *bdi = NULL; | |
847 | struct rb_node **p; | |
848 | ||
849 | spin_lock_bh(&bdi_lock); | |
850 | p = bdi_lookup_rb_node(id, NULL); | |
851 | if (*p) { | |
852 | bdi = rb_entry(*p, struct backing_dev_info, rb_node); | |
853 | bdi_get(bdi); | |
854 | } | |
855 | spin_unlock_bh(&bdi_lock); | |
856 | ||
857 | return bdi; | |
858 | } | |
859 | ||
7c4cc300 | 860 | int bdi_register_va(struct backing_dev_info *bdi, const char *fmt, va_list args) |
46100071 | 861 | { |
46100071 | 862 | struct device *dev; |
34f8fe50 | 863 | struct rb_node *parent, **p; |
e98be2d5 | 864 | |
46100071 TH |
865 | if (bdi->dev) /* The driver needs to use separate queues per device */ |
866 | return 0; | |
e98be2d5 | 867 | |
6bd87eec CH |
868 | vsnprintf(bdi->dev_name, sizeof(bdi->dev_name), fmt, args); |
869 | dev = device_create(bdi_class, NULL, MKDEV(0, 0), bdi, bdi->dev_name); | |
46100071 TH |
870 | if (IS_ERR(dev)) |
871 | return PTR_ERR(dev); | |
04fbfdc1 | 872 | |
e8cb72b3 | 873 | cgwb_bdi_register(bdi); |
46100071 | 874 | bdi->dev = dev; |
b2e8fb6e | 875 | |
6d0e4827 | 876 | bdi_debug_register(bdi, dev_name(dev)); |
46100071 TH |
877 | set_bit(WB_registered, &bdi->wb.state); |
878 | ||
879 | spin_lock_bh(&bdi_lock); | |
34f8fe50 TH |
880 | |
881 | bdi->id = ++bdi_id_cursor; | |
882 | ||
883 | p = bdi_lookup_rb_node(bdi->id, &parent); | |
884 | rb_link_node(&bdi->rb_node, parent, p); | |
885 | rb_insert_color(&bdi->rb_node, &bdi_tree); | |
886 | ||
46100071 | 887 | list_add_tail_rcu(&bdi->bdi_list, &bdi_list); |
34f8fe50 | 888 | |
46100071 TH |
889 | spin_unlock_bh(&bdi_lock); |
890 | ||
891 | trace_writeback_bdi_register(bdi); | |
892 | return 0; | |
b2e8fb6e | 893 | } |
baf7a616 | 894 | |
7c4cc300 | 895 | int bdi_register(struct backing_dev_info *bdi, const char *fmt, ...) |
baf7a616 JK |
896 | { |
897 | va_list args; | |
898 | int ret; | |
899 | ||
900 | va_start(args, fmt); | |
7c4cc300 | 901 | ret = bdi_register_va(bdi, fmt, args); |
baf7a616 JK |
902 | va_end(args); |
903 | return ret; | |
904 | } | |
46100071 | 905 | EXPORT_SYMBOL(bdi_register); |
b2e8fb6e | 906 | |
3c5d202b | 907 | void bdi_set_owner(struct backing_dev_info *bdi, struct device *owner) |
df08c32c | 908 | { |
3c5d202b | 909 | WARN_ON_ONCE(bdi->owner); |
df08c32c DW |
910 | bdi->owner = owner; |
911 | get_device(owner); | |
df08c32c | 912 | } |
df08c32c | 913 | |
46100071 TH |
914 | /* |
915 | * Remove bdi from bdi_list, and ensure that it is no longer visible | |
916 | */ | |
917 | static void bdi_remove_from_list(struct backing_dev_info *bdi) | |
918 | { | |
919 | spin_lock_bh(&bdi_lock); | |
34f8fe50 | 920 | rb_erase(&bdi->rb_node, &bdi_tree); |
46100071 TH |
921 | list_del_rcu(&bdi->bdi_list); |
922 | spin_unlock_bh(&bdi_lock); | |
b2e8fb6e | 923 | |
46100071 TH |
924 | synchronize_rcu_expedited(); |
925 | } | |
cf0ca9fe | 926 | |
b02176f3 | 927 | void bdi_unregister(struct backing_dev_info *bdi) |
b2e8fb6e | 928 | { |
5ed964f8 CH |
929 | del_timer_sync(&bdi->laptop_mode_wb_timer); |
930 | ||
f0054bb1 TH |
931 | /* make sure nobody finds us on the bdi_list anymore */ |
932 | bdi_remove_from_list(bdi); | |
933 | wb_shutdown(&bdi->wb); | |
b1c51afc | 934 | cgwb_bdi_unregister(bdi); |
7a401a97 | 935 | |
3c376dfa ML |
936 | /* |
937 | * If this BDI's min ratio has been set, use bdi_set_min_ratio() to | |
938 | * update the global bdi_min_ratio. | |
939 | */ | |
940 | if (bdi->min_ratio) | |
941 | bdi_set_min_ratio(bdi, 0); | |
942 | ||
c4db59d3 CH |
943 | if (bdi->dev) { |
944 | bdi_debug_unregister(bdi); | |
945 | device_unregister(bdi->dev); | |
946 | bdi->dev = NULL; | |
947 | } | |
df08c32c DW |
948 | |
949 | if (bdi->owner) { | |
950 | put_device(bdi->owner); | |
951 | bdi->owner = NULL; | |
952 | } | |
b02176f3 | 953 | } |
c6fd3ac0 | 954 | EXPORT_SYMBOL(bdi_unregister); |
c4db59d3 | 955 | |
d03f6cdc JK |
956 | static void release_bdi(struct kref *ref) |
957 | { | |
958 | struct backing_dev_info *bdi = | |
959 | container_of(ref, struct backing_dev_info, refcnt); | |
960 | ||
702f2d1e | 961 | WARN_ON_ONCE(test_bit(WB_registered, &bdi->wb.state)); |
2e82b84c JK |
962 | WARN_ON_ONCE(bdi->dev); |
963 | wb_exit(&bdi->wb); | |
d03f6cdc JK |
964 | kfree(bdi); |
965 | } | |
966 | ||
967 | void bdi_put(struct backing_dev_info *bdi) | |
968 | { | |
969 | kref_put(&bdi->refcnt, release_bdi); | |
970 | } | |
62bf42ad | 971 | EXPORT_SYMBOL(bdi_put); |
d03f6cdc | 972 | |
ccdf7741 CH |
973 | struct backing_dev_info *inode_to_bdi(struct inode *inode) |
974 | { | |
975 | struct super_block *sb; | |
976 | ||
977 | if (!inode) | |
978 | return &noop_backing_dev_info; | |
979 | ||
980 | sb = inode->i_sb; | |
981 | #ifdef CONFIG_BLOCK | |
982 | if (sb_is_blkdev_sb(sb)) | |
983 | return I_BDEV(inode)->bd_disk->bdi; | |
984 | #endif | |
985 | return sb->s_bdi; | |
986 | } | |
987 | EXPORT_SYMBOL(inode_to_bdi); | |
988 | ||
eb7ae5e0 CH |
989 | const char *bdi_dev_name(struct backing_dev_info *bdi) |
990 | { | |
991 | if (!bdi || !bdi->dev) | |
992 | return bdi_unknown_name; | |
6bd87eec | 993 | return bdi->dev_name; |
eb7ae5e0 CH |
994 | } |
995 | EXPORT_SYMBOL_GPL(bdi_dev_name); |