Commit | Line | Data |
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457c8996 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
3fcfab16 AM |
2 | |
3 | #include <linux/wait.h> | |
34f8fe50 | 4 | #include <linux/rbtree.h> |
3fcfab16 | 5 | #include <linux/backing-dev.h> |
03ba3782 JA |
6 | #include <linux/kthread.h> |
7 | #include <linux/freezer.h> | |
3fcfab16 | 8 | #include <linux/fs.h> |
26160158 | 9 | #include <linux/pagemap.h> |
03ba3782 | 10 | #include <linux/mm.h> |
3fcfab16 AM |
11 | #include <linux/sched.h> |
12 | #include <linux/module.h> | |
cf0ca9fe PZ |
13 | #include <linux/writeback.h> |
14 | #include <linux/device.h> | |
455b2864 | 15 | #include <trace/events/writeback.h> |
cf0ca9fe | 16 | |
5129a469 JE |
17 | struct backing_dev_info noop_backing_dev_info = { |
18 | .name = "noop", | |
976e48f8 | 19 | .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK, |
5129a469 | 20 | }; |
a212b105 | 21 | EXPORT_SYMBOL_GPL(noop_backing_dev_info); |
5129a469 | 22 | |
cf0ca9fe | 23 | static struct class *bdi_class; |
68f23b89 | 24 | 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 | ||
76f1418b MS |
38 | #ifdef CONFIG_DEBUG_FS |
39 | #include <linux/debugfs.h> | |
40 | #include <linux/seq_file.h> | |
41 | ||
42 | static struct dentry *bdi_debug_root; | |
43 | ||
44 | static void bdi_debug_init(void) | |
45 | { | |
46 | bdi_debug_root = debugfs_create_dir("bdi", NULL); | |
47 | } | |
48 | ||
49 | static int bdi_debug_stats_show(struct seq_file *m, void *v) | |
50 | { | |
51 | struct backing_dev_info *bdi = m->private; | |
c1955ce3 | 52 | struct bdi_writeback *wb = &bdi->wb; |
364aeb28 DR |
53 | unsigned long background_thresh; |
54 | unsigned long dirty_thresh; | |
0d960a38 | 55 | unsigned long wb_thresh; |
0ae45f63 | 56 | unsigned long nr_dirty, nr_io, nr_more_io, nr_dirty_time; |
f09b00d3 JA |
57 | struct inode *inode; |
58 | ||
0ae45f63 | 59 | nr_dirty = nr_io = nr_more_io = nr_dirty_time = 0; |
f758eeab | 60 | spin_lock(&wb->list_lock); |
c7f54084 | 61 | list_for_each_entry(inode, &wb->b_dirty, i_io_list) |
c1955ce3 | 62 | nr_dirty++; |
c7f54084 | 63 | list_for_each_entry(inode, &wb->b_io, i_io_list) |
c1955ce3 | 64 | nr_io++; |
c7f54084 | 65 | list_for_each_entry(inode, &wb->b_more_io, i_io_list) |
c1955ce3 | 66 | nr_more_io++; |
c7f54084 | 67 | list_for_each_entry(inode, &wb->b_dirty_time, i_io_list) |
0ae45f63 TT |
68 | if (inode->i_state & I_DIRTY_TIME) |
69 | nr_dirty_time++; | |
f758eeab | 70 | spin_unlock(&wb->list_lock); |
76f1418b | 71 | |
16c4042f | 72 | global_dirty_limits(&background_thresh, &dirty_thresh); |
0d960a38 | 73 | wb_thresh = wb_calc_thresh(wb, dirty_thresh); |
76f1418b MS |
74 | |
75 | #define K(x) ((x) << (PAGE_SHIFT - 10)) | |
76 | seq_printf(m, | |
00821b00 WF |
77 | "BdiWriteback: %10lu kB\n" |
78 | "BdiReclaimable: %10lu kB\n" | |
79 | "BdiDirtyThresh: %10lu kB\n" | |
80 | "DirtyThresh: %10lu kB\n" | |
81 | "BackgroundThresh: %10lu kB\n" | |
c8e28ce0 | 82 | "BdiDirtied: %10lu kB\n" |
00821b00 WF |
83 | "BdiWritten: %10lu kB\n" |
84 | "BdiWriteBandwidth: %10lu kBps\n" | |
85 | "b_dirty: %10lu\n" | |
86 | "b_io: %10lu\n" | |
87 | "b_more_io: %10lu\n" | |
0ae45f63 | 88 | "b_dirty_time: %10lu\n" |
00821b00 WF |
89 | "bdi_list: %10u\n" |
90 | "state: %10lx\n", | |
93f78d88 TH |
91 | (unsigned long) K(wb_stat(wb, WB_WRITEBACK)), |
92 | (unsigned long) K(wb_stat(wb, WB_RECLAIMABLE)), | |
0d960a38 | 93 | K(wb_thresh), |
f7d2b1ec JK |
94 | K(dirty_thresh), |
95 | K(background_thresh), | |
93f78d88 TH |
96 | (unsigned long) K(wb_stat(wb, WB_DIRTIED)), |
97 | (unsigned long) K(wb_stat(wb, WB_WRITTEN)), | |
a88a341a | 98 | (unsigned long) K(wb->write_bandwidth), |
f7d2b1ec JK |
99 | nr_dirty, |
100 | nr_io, | |
101 | nr_more_io, | |
0ae45f63 | 102 | nr_dirty_time, |
4452226e | 103 | !list_empty(&bdi->bdi_list), bdi->wb.state); |
76f1418b MS |
104 | #undef K |
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 | ||
152 | #define K(pages) ((pages) << (PAGE_SHIFT - 10)) | |
153 | ||
154 | #define BDI_SHOW(name, expr) \ | |
155 | static ssize_t name##_show(struct device *dev, \ | |
156 | struct device_attribute *attr, char *page) \ | |
157 | { \ | |
158 | struct backing_dev_info *bdi = dev_get_drvdata(dev); \ | |
159 | \ | |
160 | return snprintf(page, PAGE_SIZE-1, "%lld\n", (long long)expr); \ | |
d9e1241e GKH |
161 | } \ |
162 | static DEVICE_ATTR_RW(name); | |
cf0ca9fe PZ |
163 | |
164 | BDI_SHOW(read_ahead_kb, K(bdi->ra_pages)) | |
165 | ||
189d3c4a PZ |
166 | static ssize_t min_ratio_store(struct device *dev, |
167 | struct device_attribute *attr, const char *buf, size_t count) | |
168 | { | |
169 | struct backing_dev_info *bdi = dev_get_drvdata(dev); | |
189d3c4a | 170 | unsigned int ratio; |
7034ed13 NJ |
171 | ssize_t ret; |
172 | ||
173 | ret = kstrtouint(buf, 10, &ratio); | |
174 | if (ret < 0) | |
175 | return ret; | |
176 | ||
177 | ret = bdi_set_min_ratio(bdi, ratio); | |
178 | if (!ret) | |
179 | ret = count; | |
189d3c4a | 180 | |
189d3c4a PZ |
181 | return ret; |
182 | } | |
183 | BDI_SHOW(min_ratio, bdi->min_ratio) | |
184 | ||
a42dde04 PZ |
185 | static ssize_t max_ratio_store(struct device *dev, |
186 | struct device_attribute *attr, const char *buf, size_t count) | |
187 | { | |
188 | struct backing_dev_info *bdi = dev_get_drvdata(dev); | |
a42dde04 | 189 | unsigned int ratio; |
7034ed13 NJ |
190 | ssize_t ret; |
191 | ||
192 | ret = kstrtouint(buf, 10, &ratio); | |
193 | if (ret < 0) | |
194 | return ret; | |
195 | ||
196 | ret = bdi_set_max_ratio(bdi, ratio); | |
197 | if (!ret) | |
198 | ret = count; | |
a42dde04 | 199 | |
a42dde04 PZ |
200 | return ret; |
201 | } | |
202 | BDI_SHOW(max_ratio, bdi->max_ratio) | |
203 | ||
7d311cda DW |
204 | static ssize_t stable_pages_required_show(struct device *dev, |
205 | struct device_attribute *attr, | |
206 | char *page) | |
207 | { | |
208 | struct backing_dev_info *bdi = dev_get_drvdata(dev); | |
209 | ||
210 | return snprintf(page, PAGE_SIZE-1, "%d\n", | |
211 | bdi_cap_stable_pages_required(bdi) ? 1 : 0); | |
212 | } | |
d9e1241e GKH |
213 | static DEVICE_ATTR_RO(stable_pages_required); |
214 | ||
215 | static struct attribute *bdi_dev_attrs[] = { | |
216 | &dev_attr_read_ahead_kb.attr, | |
217 | &dev_attr_min_ratio.attr, | |
218 | &dev_attr_max_ratio.attr, | |
219 | &dev_attr_stable_pages_required.attr, | |
220 | NULL, | |
cf0ca9fe | 221 | }; |
d9e1241e | 222 | ATTRIBUTE_GROUPS(bdi_dev); |
cf0ca9fe PZ |
223 | |
224 | static __init int bdi_class_init(void) | |
225 | { | |
226 | bdi_class = class_create(THIS_MODULE, "bdi"); | |
14421453 AB |
227 | if (IS_ERR(bdi_class)) |
228 | return PTR_ERR(bdi_class); | |
229 | ||
d9e1241e | 230 | bdi_class->dev_groups = bdi_dev_groups; |
76f1418b | 231 | bdi_debug_init(); |
d03f6cdc | 232 | |
cf0ca9fe PZ |
233 | return 0; |
234 | } | |
76f1418b | 235 | postcore_initcall(bdi_class_init); |
cf0ca9fe | 236 | |
2e82b84c JK |
237 | static int bdi_init(struct backing_dev_info *bdi); |
238 | ||
26160158 JA |
239 | static int __init default_bdi_init(void) |
240 | { | |
241 | int err; | |
242 | ||
a2b90f11 MW |
243 | bdi_wq = alloc_workqueue("writeback", WQ_MEM_RECLAIM | WQ_UNBOUND | |
244 | WQ_SYSFS, 0); | |
839a8e86 TH |
245 | if (!bdi_wq) |
246 | return -ENOMEM; | |
247 | ||
976e48f8 | 248 | err = bdi_init(&noop_backing_dev_info); |
26160158 JA |
249 | |
250 | return err; | |
251 | } | |
252 | subsys_initcall(default_bdi_init); | |
253 | ||
6467716a | 254 | /* |
f0054bb1 | 255 | * This function is used when the first inode for this wb is marked dirty. It |
6467716a AB |
256 | * wakes-up the corresponding bdi thread which should then take care of the |
257 | * periodic background write-out of dirty inodes. Since the write-out would | |
258 | * starts only 'dirty_writeback_interval' centisecs from now anyway, we just | |
259 | * set up a timer which wakes the bdi thread up later. | |
260 | * | |
261 | * Note, we wouldn't bother setting up the timer, but this function is on the | |
262 | * fast-path (used by '__mark_inode_dirty()'), so we save few context switches | |
263 | * by delaying the wake-up. | |
6ca738d6 DB |
264 | * |
265 | * We have to be careful not to postpone flush work if it is scheduled for | |
266 | * earlier. Thus we use queue_delayed_work(). | |
6467716a | 267 | */ |
f0054bb1 | 268 | void wb_wakeup_delayed(struct bdi_writeback *wb) |
6467716a AB |
269 | { |
270 | unsigned long timeout; | |
271 | ||
272 | timeout = msecs_to_jiffies(dirty_writeback_interval * 10); | |
f0054bb1 TH |
273 | spin_lock_bh(&wb->work_lock); |
274 | if (test_bit(WB_registered, &wb->state)) | |
275 | queue_delayed_work(bdi_wq, &wb->dwork, timeout); | |
276 | spin_unlock_bh(&wb->work_lock); | |
03ba3782 JA |
277 | } |
278 | ||
cfc4ba53 | 279 | /* |
a88a341a | 280 | * Initial write bandwidth: 100 MB/s |
cfc4ba53 | 281 | */ |
a88a341a | 282 | #define INIT_BW (100 << (20 - PAGE_SHIFT)) |
cfc4ba53 | 283 | |
8395cd9f | 284 | static int wb_init(struct bdi_writeback *wb, struct backing_dev_info *bdi, |
a13f35e8 | 285 | int blkcg_id, gfp_t gfp) |
cf0ca9fe | 286 | { |
93f78d88 | 287 | int i, err; |
cf0ca9fe | 288 | |
6467716a | 289 | memset(wb, 0, sizeof(*wb)); |
f1d0b063 | 290 | |
810df54a JK |
291 | if (wb != &bdi->wb) |
292 | bdi_get(bdi); | |
6467716a AB |
293 | wb->bdi = bdi; |
294 | wb->last_old_flush = jiffies; | |
295 | INIT_LIST_HEAD(&wb->b_dirty); | |
296 | INIT_LIST_HEAD(&wb->b_io); | |
297 | INIT_LIST_HEAD(&wb->b_more_io); | |
0ae45f63 | 298 | INIT_LIST_HEAD(&wb->b_dirty_time); |
f758eeab | 299 | spin_lock_init(&wb->list_lock); |
66f3b8e2 | 300 | |
a88a341a TH |
301 | wb->bw_time_stamp = jiffies; |
302 | wb->balanced_dirty_ratelimit = INIT_BW; | |
303 | wb->dirty_ratelimit = INIT_BW; | |
304 | wb->write_bandwidth = INIT_BW; | |
305 | wb->avg_write_bandwidth = INIT_BW; | |
cf0ca9fe | 306 | |
f0054bb1 TH |
307 | spin_lock_init(&wb->work_lock); |
308 | INIT_LIST_HEAD(&wb->work_list); | |
309 | INIT_DELAYED_WORK(&wb->dwork, wb_workfn); | |
b57d74af | 310 | wb->dirty_sleep = jiffies; |
c284de61 | 311 | |
a13f35e8 | 312 | wb->congested = wb_congested_get_create(bdi, blkcg_id, gfp); |
810df54a JK |
313 | if (!wb->congested) { |
314 | err = -ENOMEM; | |
315 | goto out_put_bdi; | |
316 | } | |
a13f35e8 | 317 | |
8395cd9f | 318 | err = fprop_local_init_percpu(&wb->completions, gfp); |
a88a341a | 319 | if (err) |
a13f35e8 | 320 | goto out_put_cong; |
c284de61 | 321 | |
93f78d88 | 322 | for (i = 0; i < NR_WB_STAT_ITEMS; i++) { |
8395cd9f | 323 | err = percpu_counter_init(&wb->stat[i], 0, gfp); |
a13f35e8 TH |
324 | if (err) |
325 | goto out_destroy_stat; | |
93f78d88 | 326 | } |
cf0ca9fe | 327 | |
93f78d88 | 328 | return 0; |
a13f35e8 TH |
329 | |
330 | out_destroy_stat: | |
078c6c3a | 331 | while (i--) |
a13f35e8 TH |
332 | percpu_counter_destroy(&wb->stat[i]); |
333 | fprop_local_destroy_percpu(&wb->completions); | |
334 | out_put_cong: | |
335 | wb_congested_put(wb->congested); | |
810df54a JK |
336 | out_put_bdi: |
337 | if (wb != &bdi->wb) | |
338 | bdi_put(bdi); | |
a13f35e8 | 339 | return err; |
cf0ca9fe | 340 | } |
cf0ca9fe | 341 | |
e8cb72b3 JK |
342 | static void cgwb_remove_from_bdi_list(struct bdi_writeback *wb); |
343 | ||
03ba3782 JA |
344 | /* |
345 | * Remove bdi from the global list and shutdown any threads we have running | |
346 | */ | |
46100071 | 347 | static void wb_shutdown(struct bdi_writeback *wb) |
66f3b8e2 | 348 | { |
c4db59d3 | 349 | /* Make sure nobody queues further work */ |
46100071 TH |
350 | spin_lock_bh(&wb->work_lock); |
351 | if (!test_and_clear_bit(WB_registered, &wb->state)) { | |
352 | spin_unlock_bh(&wb->work_lock); | |
03ba3782 | 353 | return; |
c4db59d3 | 354 | } |
46100071 | 355 | spin_unlock_bh(&wb->work_lock); |
03ba3782 | 356 | |
e8cb72b3 | 357 | cgwb_remove_from_bdi_list(wb); |
03ba3782 | 358 | /* |
46100071 TH |
359 | * Drain work list and shutdown the delayed_work. !WB_registered |
360 | * tells wb_workfn() that @wb is dying and its work_list needs to | |
361 | * be drained no matter what. | |
03ba3782 | 362 | */ |
46100071 TH |
363 | mod_delayed_work(bdi_wq, &wb->dwork, 0); |
364 | flush_delayed_work(&wb->dwork); | |
365 | WARN_ON(!list_empty(&wb->work_list)); | |
366 | } | |
367 | ||
f0054bb1 | 368 | static void wb_exit(struct bdi_writeback *wb) |
93f78d88 TH |
369 | { |
370 | int i; | |
371 | ||
372 | WARN_ON(delayed_work_pending(&wb->dwork)); | |
373 | ||
374 | for (i = 0; i < NR_WB_STAT_ITEMS; i++) | |
375 | percpu_counter_destroy(&wb->stat[i]); | |
6467716a | 376 | |
a88a341a | 377 | fprop_local_destroy_percpu(&wb->completions); |
a13f35e8 | 378 | wb_congested_put(wb->congested); |
810df54a JK |
379 | if (wb != &wb->bdi->wb) |
380 | bdi_put(wb->bdi); | |
a88a341a | 381 | } |
e98be2d5 | 382 | |
52ebea74 TH |
383 | #ifdef CONFIG_CGROUP_WRITEBACK |
384 | ||
385 | #include <linux/memcontrol.h> | |
386 | ||
387 | /* | |
388 | * cgwb_lock protects bdi->cgwb_tree, bdi->cgwb_congested_tree, | |
389 | * blkcg->cgwb_list, and memcg->cgwb_list. bdi->cgwb_tree is also RCU | |
4514451e | 390 | * protected. |
52ebea74 TH |
391 | */ |
392 | static DEFINE_SPINLOCK(cgwb_lock); | |
f1834646 | 393 | static struct workqueue_struct *cgwb_release_wq; |
52ebea74 TH |
394 | |
395 | /** | |
396 | * wb_congested_get_create - get or create a wb_congested | |
397 | * @bdi: associated bdi | |
398 | * @blkcg_id: ID of the associated blkcg | |
399 | * @gfp: allocation mask | |
400 | * | |
401 | * Look up the wb_congested for @blkcg_id on @bdi. If missing, create one. | |
402 | * The returned wb_congested has its reference count incremented. Returns | |
403 | * NULL on failure. | |
404 | */ | |
405 | struct bdi_writeback_congested * | |
406 | wb_congested_get_create(struct backing_dev_info *bdi, int blkcg_id, gfp_t gfp) | |
407 | { | |
408 | struct bdi_writeback_congested *new_congested = NULL, *congested; | |
409 | struct rb_node **node, *parent; | |
410 | unsigned long flags; | |
52ebea74 TH |
411 | retry: |
412 | spin_lock_irqsave(&cgwb_lock, flags); | |
413 | ||
414 | node = &bdi->cgwb_congested_tree.rb_node; | |
415 | parent = NULL; | |
416 | ||
417 | while (*node != NULL) { | |
418 | parent = *node; | |
bc71226b GT |
419 | congested = rb_entry(parent, struct bdi_writeback_congested, |
420 | rb_node); | |
52ebea74 TH |
421 | if (congested->blkcg_id < blkcg_id) |
422 | node = &parent->rb_left; | |
423 | else if (congested->blkcg_id > blkcg_id) | |
424 | node = &parent->rb_right; | |
425 | else | |
426 | goto found; | |
427 | } | |
428 | ||
429 | if (new_congested) { | |
430 | /* !found and storage for new one already allocated, insert */ | |
431 | congested = new_congested; | |
52ebea74 TH |
432 | rb_link_node(&congested->rb_node, parent, node); |
433 | rb_insert_color(&congested->rb_node, &bdi->cgwb_congested_tree); | |
e58dd0de SAS |
434 | spin_unlock_irqrestore(&cgwb_lock, flags); |
435 | return congested; | |
52ebea74 TH |
436 | } |
437 | ||
438 | spin_unlock_irqrestore(&cgwb_lock, flags); | |
439 | ||
440 | /* allocate storage for new one and retry */ | |
441 | new_congested = kzalloc(sizeof(*new_congested), gfp); | |
442 | if (!new_congested) | |
443 | return NULL; | |
444 | ||
e58dd0de | 445 | refcount_set(&new_congested->refcnt, 1); |
b7d680d7 | 446 | new_congested->__bdi = bdi; |
52ebea74 TH |
447 | new_congested->blkcg_id = blkcg_id; |
448 | goto retry; | |
449 | ||
450 | found: | |
e58dd0de | 451 | refcount_inc(&congested->refcnt); |
52ebea74 TH |
452 | spin_unlock_irqrestore(&cgwb_lock, flags); |
453 | kfree(new_congested); | |
454 | return congested; | |
455 | } | |
456 | ||
457 | /** | |
458 | * wb_congested_put - put a wb_congested | |
459 | * @congested: wb_congested to put | |
460 | * | |
461 | * Put @congested and destroy it if the refcnt reaches zero. | |
462 | */ | |
463 | void wb_congested_put(struct bdi_writeback_congested *congested) | |
464 | { | |
52ebea74 TH |
465 | unsigned long flags; |
466 | ||
060288a7 | 467 | if (!refcount_dec_and_lock_irqsave(&congested->refcnt, &cgwb_lock, &flags)) |
52ebea74 | 468 | return; |
52ebea74 | 469 | |
a20135ff | 470 | /* bdi might already have been destroyed leaving @congested unlinked */ |
b7d680d7 | 471 | if (congested->__bdi) { |
a20135ff | 472 | rb_erase(&congested->rb_node, |
b7d680d7 JK |
473 | &congested->__bdi->cgwb_congested_tree); |
474 | congested->__bdi = NULL; | |
a20135ff TH |
475 | } |
476 | ||
52ebea74 TH |
477 | spin_unlock_irqrestore(&cgwb_lock, flags); |
478 | kfree(congested); | |
52ebea74 TH |
479 | } |
480 | ||
481 | static void cgwb_release_workfn(struct work_struct *work) | |
482 | { | |
483 | struct bdi_writeback *wb = container_of(work, struct bdi_writeback, | |
484 | release_work); | |
59b57717 | 485 | struct blkcg *blkcg = css_to_blkcg(wb->blkcg_css); |
52ebea74 | 486 | |
3ee7e869 | 487 | mutex_lock(&wb->bdi->cgwb_release_mutex); |
52ebea74 TH |
488 | wb_shutdown(wb); |
489 | ||
490 | css_put(wb->memcg_css); | |
491 | css_put(wb->blkcg_css); | |
3ee7e869 | 492 | mutex_unlock(&wb->bdi->cgwb_release_mutex); |
52ebea74 | 493 | |
59b57717 DZF |
494 | /* triggers blkg destruction if cgwb_refcnt becomes zero */ |
495 | blkcg_cgwb_put(blkcg); | |
496 | ||
841710aa | 497 | fprop_local_destroy_percpu(&wb->memcg_completions); |
52ebea74 TH |
498 | percpu_ref_exit(&wb->refcnt); |
499 | wb_exit(wb); | |
500 | kfree_rcu(wb, rcu); | |
52ebea74 TH |
501 | } |
502 | ||
503 | static void cgwb_release(struct percpu_ref *refcnt) | |
504 | { | |
505 | struct bdi_writeback *wb = container_of(refcnt, struct bdi_writeback, | |
506 | refcnt); | |
f1834646 | 507 | queue_work(cgwb_release_wq, &wb->release_work); |
52ebea74 TH |
508 | } |
509 | ||
510 | static void cgwb_kill(struct bdi_writeback *wb) | |
511 | { | |
512 | lockdep_assert_held(&cgwb_lock); | |
513 | ||
514 | WARN_ON(!radix_tree_delete(&wb->bdi->cgwb_tree, wb->memcg_css->id)); | |
515 | list_del(&wb->memcg_node); | |
516 | list_del(&wb->blkcg_node); | |
517 | percpu_ref_kill(&wb->refcnt); | |
518 | } | |
519 | ||
e8cb72b3 JK |
520 | static void cgwb_remove_from_bdi_list(struct bdi_writeback *wb) |
521 | { | |
522 | spin_lock_irq(&cgwb_lock); | |
523 | list_del_rcu(&wb->bdi_node); | |
524 | spin_unlock_irq(&cgwb_lock); | |
525 | } | |
526 | ||
52ebea74 TH |
527 | static int cgwb_create(struct backing_dev_info *bdi, |
528 | struct cgroup_subsys_state *memcg_css, gfp_t gfp) | |
529 | { | |
530 | struct mem_cgroup *memcg; | |
531 | struct cgroup_subsys_state *blkcg_css; | |
532 | struct blkcg *blkcg; | |
533 | struct list_head *memcg_cgwb_list, *blkcg_cgwb_list; | |
534 | struct bdi_writeback *wb; | |
535 | unsigned long flags; | |
536 | int ret = 0; | |
537 | ||
538 | memcg = mem_cgroup_from_css(memcg_css); | |
c165b3e3 | 539 | blkcg_css = cgroup_get_e_css(memcg_css->cgroup, &io_cgrp_subsys); |
52ebea74 | 540 | blkcg = css_to_blkcg(blkcg_css); |
9ccc3617 | 541 | memcg_cgwb_list = &memcg->cgwb_list; |
52ebea74 TH |
542 | blkcg_cgwb_list = &blkcg->cgwb_list; |
543 | ||
544 | /* look up again under lock and discard on blkcg mismatch */ | |
545 | spin_lock_irqsave(&cgwb_lock, flags); | |
546 | wb = radix_tree_lookup(&bdi->cgwb_tree, memcg_css->id); | |
547 | if (wb && wb->blkcg_css != blkcg_css) { | |
548 | cgwb_kill(wb); | |
549 | wb = NULL; | |
550 | } | |
551 | spin_unlock_irqrestore(&cgwb_lock, flags); | |
552 | if (wb) | |
553 | goto out_put; | |
554 | ||
555 | /* need to create a new one */ | |
556 | wb = kmalloc(sizeof(*wb), gfp); | |
0b045bd1 CJ |
557 | if (!wb) { |
558 | ret = -ENOMEM; | |
559 | goto out_put; | |
560 | } | |
52ebea74 | 561 | |
a13f35e8 | 562 | ret = wb_init(wb, bdi, blkcg_css->id, gfp); |
52ebea74 TH |
563 | if (ret) |
564 | goto err_free; | |
565 | ||
566 | ret = percpu_ref_init(&wb->refcnt, cgwb_release, 0, gfp); | |
567 | if (ret) | |
568 | goto err_wb_exit; | |
569 | ||
841710aa TH |
570 | ret = fprop_local_init_percpu(&wb->memcg_completions, gfp); |
571 | if (ret) | |
572 | goto err_ref_exit; | |
573 | ||
52ebea74 TH |
574 | wb->memcg_css = memcg_css; |
575 | wb->blkcg_css = blkcg_css; | |
576 | INIT_WORK(&wb->release_work, cgwb_release_workfn); | |
577 | set_bit(WB_registered, &wb->state); | |
03ba3782 JA |
578 | |
579 | /* | |
52ebea74 TH |
580 | * The root wb determines the registered state of the whole bdi and |
581 | * memcg_cgwb_list and blkcg_cgwb_list's next pointers indicate | |
582 | * whether they're still online. Don't link @wb if any is dead. | |
583 | * See wb_memcg_offline() and wb_blkcg_offline(). | |
03ba3782 | 584 | */ |
52ebea74 TH |
585 | ret = -ENODEV; |
586 | spin_lock_irqsave(&cgwb_lock, flags); | |
587 | if (test_bit(WB_registered, &bdi->wb.state) && | |
588 | blkcg_cgwb_list->next && memcg_cgwb_list->next) { | |
589 | /* we might have raced another instance of this function */ | |
590 | ret = radix_tree_insert(&bdi->cgwb_tree, memcg_css->id, wb); | |
591 | if (!ret) { | |
b817525a | 592 | list_add_tail_rcu(&wb->bdi_node, &bdi->wb_list); |
52ebea74 TH |
593 | list_add(&wb->memcg_node, memcg_cgwb_list); |
594 | list_add(&wb->blkcg_node, blkcg_cgwb_list); | |
59b57717 | 595 | blkcg_cgwb_get(blkcg); |
52ebea74 TH |
596 | css_get(memcg_css); |
597 | css_get(blkcg_css); | |
598 | } | |
599 | } | |
600 | spin_unlock_irqrestore(&cgwb_lock, flags); | |
601 | if (ret) { | |
602 | if (ret == -EEXIST) | |
603 | ret = 0; | |
a13f35e8 | 604 | goto err_fprop_exit; |
52ebea74 TH |
605 | } |
606 | goto out_put; | |
607 | ||
841710aa TH |
608 | err_fprop_exit: |
609 | fprop_local_destroy_percpu(&wb->memcg_completions); | |
52ebea74 TH |
610 | err_ref_exit: |
611 | percpu_ref_exit(&wb->refcnt); | |
612 | err_wb_exit: | |
613 | wb_exit(wb); | |
614 | err_free: | |
615 | kfree(wb); | |
616 | out_put: | |
617 | css_put(blkcg_css); | |
618 | return ret; | |
66f3b8e2 JA |
619 | } |
620 | ||
52ebea74 | 621 | /** |
ed288dc0 | 622 | * wb_get_lookup - get wb for a given memcg |
52ebea74 TH |
623 | * @bdi: target bdi |
624 | * @memcg_css: cgroup_subsys_state of the target memcg (must have positive ref) | |
52ebea74 | 625 | * |
ed288dc0 TH |
626 | * Try to get the wb for @memcg_css on @bdi. The returned wb has its |
627 | * refcount incremented. | |
52ebea74 TH |
628 | * |
629 | * This function uses css_get() on @memcg_css and thus expects its refcnt | |
630 | * to be positive on invocation. IOW, rcu_read_lock() protection on | |
631 | * @memcg_css isn't enough. try_get it before calling this function. | |
632 | * | |
633 | * A wb is keyed by its associated memcg. As blkcg implicitly enables | |
634 | * memcg on the default hierarchy, memcg association is guaranteed to be | |
635 | * more specific (equal or descendant to the associated blkcg) and thus can | |
636 | * identify both the memcg and blkcg associations. | |
637 | * | |
638 | * Because the blkcg associated with a memcg may change as blkcg is enabled | |
639 | * and disabled closer to root in the hierarchy, each wb keeps track of | |
640 | * both the memcg and blkcg associated with it and verifies the blkcg on | |
641 | * each lookup. On mismatch, the existing wb is discarded and a new one is | |
642 | * created. | |
643 | */ | |
ed288dc0 TH |
644 | struct bdi_writeback *wb_get_lookup(struct backing_dev_info *bdi, |
645 | struct cgroup_subsys_state *memcg_css) | |
646 | { | |
647 | struct bdi_writeback *wb; | |
648 | ||
649 | if (!memcg_css->parent) | |
650 | return &bdi->wb; | |
651 | ||
652 | rcu_read_lock(); | |
653 | wb = radix_tree_lookup(&bdi->cgwb_tree, memcg_css->id); | |
654 | if (wb) { | |
655 | struct cgroup_subsys_state *blkcg_css; | |
656 | ||
657 | /* see whether the blkcg association has changed */ | |
658 | blkcg_css = cgroup_get_e_css(memcg_css->cgroup, &io_cgrp_subsys); | |
659 | if (unlikely(wb->blkcg_css != blkcg_css || !wb_tryget(wb))) | |
660 | wb = NULL; | |
661 | css_put(blkcg_css); | |
662 | } | |
663 | rcu_read_unlock(); | |
664 | ||
665 | return wb; | |
666 | } | |
667 | ||
668 | /** | |
669 | * wb_get_create - get wb for a given memcg, create if necessary | |
670 | * @bdi: target bdi | |
671 | * @memcg_css: cgroup_subsys_state of the target memcg (must have positive ref) | |
672 | * @gfp: allocation mask to use | |
673 | * | |
674 | * Try to get the wb for @memcg_css on @bdi. If it doesn't exist, try to | |
675 | * create one. See wb_get_lookup() for more details. | |
676 | */ | |
52ebea74 TH |
677 | struct bdi_writeback *wb_get_create(struct backing_dev_info *bdi, |
678 | struct cgroup_subsys_state *memcg_css, | |
679 | gfp_t gfp) | |
6467716a | 680 | { |
52ebea74 TH |
681 | struct bdi_writeback *wb; |
682 | ||
d0164adc | 683 | might_sleep_if(gfpflags_allow_blocking(gfp)); |
52ebea74 TH |
684 | |
685 | if (!memcg_css->parent) | |
686 | return &bdi->wb; | |
687 | ||
688 | do { | |
ed288dc0 | 689 | wb = wb_get_lookup(bdi, memcg_css); |
52ebea74 TH |
690 | } while (!wb && !cgwb_create(bdi, memcg_css, gfp)); |
691 | ||
692 | return wb; | |
693 | } | |
6467716a | 694 | |
a13f35e8 | 695 | static int cgwb_bdi_init(struct backing_dev_info *bdi) |
52ebea74 | 696 | { |
a13f35e8 TH |
697 | int ret; |
698 | ||
52ebea74 TH |
699 | INIT_RADIX_TREE(&bdi->cgwb_tree, GFP_ATOMIC); |
700 | bdi->cgwb_congested_tree = RB_ROOT; | |
3ee7e869 | 701 | mutex_init(&bdi->cgwb_release_mutex); |
7fc5854f | 702 | init_rwsem(&bdi->wb_switch_rwsem); |
a13f35e8 TH |
703 | |
704 | ret = wb_init(&bdi->wb, bdi, 1, GFP_KERNEL); | |
705 | if (!ret) { | |
7d828602 | 706 | bdi->wb.memcg_css = &root_mem_cgroup->css; |
a13f35e8 TH |
707 | bdi->wb.blkcg_css = blkcg_root_css; |
708 | } | |
709 | return ret; | |
6467716a AB |
710 | } |
711 | ||
b1c51afc | 712 | static void cgwb_bdi_unregister(struct backing_dev_info *bdi) |
52ebea74 TH |
713 | { |
714 | struct radix_tree_iter iter; | |
715 | void **slot; | |
5318ce7d | 716 | struct bdi_writeback *wb; |
52ebea74 TH |
717 | |
718 | WARN_ON(test_bit(WB_registered, &bdi->wb.state)); | |
719 | ||
720 | spin_lock_irq(&cgwb_lock); | |
721 | radix_tree_for_each_slot(slot, &bdi->cgwb_tree, &iter, 0) | |
722 | cgwb_kill(*slot); | |
3ee7e869 | 723 | spin_unlock_irq(&cgwb_lock); |
5318ce7d | 724 | |
3ee7e869 JK |
725 | mutex_lock(&bdi->cgwb_release_mutex); |
726 | spin_lock_irq(&cgwb_lock); | |
5318ce7d JK |
727 | while (!list_empty(&bdi->wb_list)) { |
728 | wb = list_first_entry(&bdi->wb_list, struct bdi_writeback, | |
729 | bdi_node); | |
730 | spin_unlock_irq(&cgwb_lock); | |
731 | wb_shutdown(wb); | |
732 | spin_lock_irq(&cgwb_lock); | |
733 | } | |
52ebea74 | 734 | spin_unlock_irq(&cgwb_lock); |
3ee7e869 | 735 | mutex_unlock(&bdi->cgwb_release_mutex); |
52ebea74 TH |
736 | } |
737 | ||
738 | /** | |
739 | * wb_memcg_offline - kill all wb's associated with a memcg being offlined | |
740 | * @memcg: memcg being offlined | |
741 | * | |
742 | * Also prevents creation of any new wb's associated with @memcg. | |
e98be2d5 | 743 | */ |
52ebea74 TH |
744 | void wb_memcg_offline(struct mem_cgroup *memcg) |
745 | { | |
9ccc3617 | 746 | struct list_head *memcg_cgwb_list = &memcg->cgwb_list; |
52ebea74 TH |
747 | struct bdi_writeback *wb, *next; |
748 | ||
749 | spin_lock_irq(&cgwb_lock); | |
750 | list_for_each_entry_safe(wb, next, memcg_cgwb_list, memcg_node) | |
751 | cgwb_kill(wb); | |
752 | memcg_cgwb_list->next = NULL; /* prevent new wb's */ | |
753 | spin_unlock_irq(&cgwb_lock); | |
754 | } | |
755 | ||
756 | /** | |
757 | * wb_blkcg_offline - kill all wb's associated with a blkcg being offlined | |
758 | * @blkcg: blkcg being offlined | |
759 | * | |
760 | * Also prevents creation of any new wb's associated with @blkcg. | |
761 | */ | |
762 | void wb_blkcg_offline(struct blkcg *blkcg) | |
763 | { | |
52ebea74 TH |
764 | struct bdi_writeback *wb, *next; |
765 | ||
766 | spin_lock_irq(&cgwb_lock); | |
767 | list_for_each_entry_safe(wb, next, &blkcg->cgwb_list, blkcg_node) | |
768 | cgwb_kill(wb); | |
769 | blkcg->cgwb_list.next = NULL; /* prevent new wb's */ | |
770 | spin_unlock_irq(&cgwb_lock); | |
771 | } | |
772 | ||
df23de55 JK |
773 | static void cgwb_bdi_exit(struct backing_dev_info *bdi) |
774 | { | |
775 | struct rb_node *rbn; | |
776 | ||
777 | spin_lock_irq(&cgwb_lock); | |
778 | while ((rbn = rb_first(&bdi->cgwb_congested_tree))) { | |
779 | struct bdi_writeback_congested *congested = | |
780 | rb_entry(rbn, struct bdi_writeback_congested, rb_node); | |
781 | ||
782 | rb_erase(rbn, &bdi->cgwb_congested_tree); | |
b7d680d7 | 783 | congested->__bdi = NULL; /* mark @congested unlinked */ |
df23de55 JK |
784 | } |
785 | spin_unlock_irq(&cgwb_lock); | |
786 | } | |
787 | ||
e8cb72b3 JK |
788 | static void cgwb_bdi_register(struct backing_dev_info *bdi) |
789 | { | |
790 | spin_lock_irq(&cgwb_lock); | |
791 | list_add_tail_rcu(&bdi->wb.bdi_node, &bdi->wb_list); | |
792 | spin_unlock_irq(&cgwb_lock); | |
793 | } | |
794 | ||
f1834646 TH |
795 | static int __init cgwb_init(void) |
796 | { | |
797 | /* | |
798 | * There can be many concurrent release work items overwhelming | |
799 | * system_wq. Put them in a separate wq and limit concurrency. | |
800 | * There's no point in executing many of these in parallel. | |
801 | */ | |
802 | cgwb_release_wq = alloc_workqueue("cgwb_release", 0, 1); | |
803 | if (!cgwb_release_wq) | |
804 | return -ENOMEM; | |
805 | ||
806 | return 0; | |
807 | } | |
808 | subsys_initcall(cgwb_init); | |
809 | ||
52ebea74 TH |
810 | #else /* CONFIG_CGROUP_WRITEBACK */ |
811 | ||
a13f35e8 TH |
812 | static int cgwb_bdi_init(struct backing_dev_info *bdi) |
813 | { | |
814 | int err; | |
815 | ||
816 | bdi->wb_congested = kzalloc(sizeof(*bdi->wb_congested), GFP_KERNEL); | |
817 | if (!bdi->wb_congested) | |
818 | return -ENOMEM; | |
819 | ||
e58dd0de | 820 | refcount_set(&bdi->wb_congested->refcnt, 1); |
5f478e4e | 821 | |
a13f35e8 TH |
822 | err = wb_init(&bdi->wb, bdi, 1, GFP_KERNEL); |
823 | if (err) { | |
5f478e4e | 824 | wb_congested_put(bdi->wb_congested); |
a13f35e8 TH |
825 | return err; |
826 | } | |
827 | return 0; | |
828 | } | |
829 | ||
b1c51afc | 830 | static void cgwb_bdi_unregister(struct backing_dev_info *bdi) { } |
df23de55 JK |
831 | |
832 | static void cgwb_bdi_exit(struct backing_dev_info *bdi) | |
5f478e4e TH |
833 | { |
834 | wb_congested_put(bdi->wb_congested); | |
835 | } | |
52ebea74 | 836 | |
e8cb72b3 JK |
837 | static void cgwb_bdi_register(struct backing_dev_info *bdi) |
838 | { | |
839 | list_add_tail_rcu(&bdi->wb.bdi_node, &bdi->wb_list); | |
840 | } | |
841 | ||
842 | static void cgwb_remove_from_bdi_list(struct bdi_writeback *wb) | |
843 | { | |
844 | list_del_rcu(&wb->bdi_node); | |
845 | } | |
846 | ||
52ebea74 | 847 | #endif /* CONFIG_CGROUP_WRITEBACK */ |
e98be2d5 | 848 | |
2e82b84c | 849 | static int bdi_init(struct backing_dev_info *bdi) |
b2e8fb6e | 850 | { |
b817525a TH |
851 | int ret; |
852 | ||
cf0ca9fe PZ |
853 | bdi->dev = NULL; |
854 | ||
d03f6cdc | 855 | kref_init(&bdi->refcnt); |
189d3c4a | 856 | bdi->min_ratio = 0; |
a42dde04 | 857 | bdi->max_ratio = 100; |
eb608e3a | 858 | bdi->max_prop_frac = FPROP_FRAC_BASE; |
66f3b8e2 | 859 | INIT_LIST_HEAD(&bdi->bdi_list); |
b817525a | 860 | INIT_LIST_HEAD(&bdi->wb_list); |
cc395d7f | 861 | init_waitqueue_head(&bdi->wb_waitq); |
03ba3782 | 862 | |
b817525a TH |
863 | ret = cgwb_bdi_init(bdi); |
864 | ||
b817525a | 865 | return ret; |
b2e8fb6e | 866 | } |
e98be2d5 | 867 | |
d03f6cdc JK |
868 | struct backing_dev_info *bdi_alloc_node(gfp_t gfp_mask, int node_id) |
869 | { | |
870 | struct backing_dev_info *bdi; | |
871 | ||
872 | bdi = kmalloc_node(sizeof(struct backing_dev_info), | |
873 | gfp_mask | __GFP_ZERO, node_id); | |
874 | if (!bdi) | |
875 | return NULL; | |
876 | ||
877 | if (bdi_init(bdi)) { | |
878 | kfree(bdi); | |
879 | return NULL; | |
880 | } | |
881 | return bdi; | |
882 | } | |
62bf42ad | 883 | EXPORT_SYMBOL(bdi_alloc_node); |
d03f6cdc | 884 | |
34f8fe50 TH |
885 | static struct rb_node **bdi_lookup_rb_node(u64 id, struct rb_node **parentp) |
886 | { | |
887 | struct rb_node **p = &bdi_tree.rb_node; | |
888 | struct rb_node *parent = NULL; | |
889 | struct backing_dev_info *bdi; | |
890 | ||
891 | lockdep_assert_held(&bdi_lock); | |
892 | ||
893 | while (*p) { | |
894 | parent = *p; | |
895 | bdi = rb_entry(parent, struct backing_dev_info, rb_node); | |
896 | ||
897 | if (bdi->id > id) | |
898 | p = &(*p)->rb_left; | |
899 | else if (bdi->id < id) | |
900 | p = &(*p)->rb_right; | |
901 | else | |
902 | break; | |
903 | } | |
904 | ||
905 | if (parentp) | |
906 | *parentp = parent; | |
907 | return p; | |
908 | } | |
909 | ||
910 | /** | |
911 | * bdi_get_by_id - lookup and get bdi from its id | |
912 | * @id: bdi id to lookup | |
913 | * | |
914 | * Find bdi matching @id and get it. Returns NULL if the matching bdi | |
915 | * doesn't exist or is already unregistered. | |
916 | */ | |
917 | struct backing_dev_info *bdi_get_by_id(u64 id) | |
918 | { | |
919 | struct backing_dev_info *bdi = NULL; | |
920 | struct rb_node **p; | |
921 | ||
922 | spin_lock_bh(&bdi_lock); | |
923 | p = bdi_lookup_rb_node(id, NULL); | |
924 | if (*p) { | |
925 | bdi = rb_entry(*p, struct backing_dev_info, rb_node); | |
926 | bdi_get(bdi); | |
927 | } | |
928 | spin_unlock_bh(&bdi_lock); | |
929 | ||
930 | return bdi; | |
931 | } | |
932 | ||
7c4cc300 | 933 | int bdi_register_va(struct backing_dev_info *bdi, const char *fmt, va_list args) |
46100071 | 934 | { |
46100071 | 935 | struct device *dev; |
34f8fe50 | 936 | struct rb_node *parent, **p; |
e98be2d5 | 937 | |
46100071 TH |
938 | if (bdi->dev) /* The driver needs to use separate queues per device */ |
939 | return 0; | |
e98be2d5 | 940 | |
7c4cc300 | 941 | dev = device_create_vargs(bdi_class, NULL, MKDEV(0, 0), bdi, fmt, args); |
46100071 TH |
942 | if (IS_ERR(dev)) |
943 | return PTR_ERR(dev); | |
04fbfdc1 | 944 | |
e8cb72b3 | 945 | cgwb_bdi_register(bdi); |
46100071 | 946 | bdi->dev = dev; |
b2e8fb6e | 947 | |
6d0e4827 | 948 | bdi_debug_register(bdi, dev_name(dev)); |
46100071 TH |
949 | set_bit(WB_registered, &bdi->wb.state); |
950 | ||
951 | spin_lock_bh(&bdi_lock); | |
34f8fe50 TH |
952 | |
953 | bdi->id = ++bdi_id_cursor; | |
954 | ||
955 | p = bdi_lookup_rb_node(bdi->id, &parent); | |
956 | rb_link_node(&bdi->rb_node, parent, p); | |
957 | rb_insert_color(&bdi->rb_node, &bdi_tree); | |
958 | ||
46100071 | 959 | list_add_tail_rcu(&bdi->bdi_list, &bdi_list); |
34f8fe50 | 960 | |
46100071 TH |
961 | spin_unlock_bh(&bdi_lock); |
962 | ||
963 | trace_writeback_bdi_register(bdi); | |
964 | return 0; | |
b2e8fb6e | 965 | } |
baf7a616 JK |
966 | EXPORT_SYMBOL(bdi_register_va); |
967 | ||
7c4cc300 | 968 | int bdi_register(struct backing_dev_info *bdi, const char *fmt, ...) |
baf7a616 JK |
969 | { |
970 | va_list args; | |
971 | int ret; | |
972 | ||
973 | va_start(args, fmt); | |
7c4cc300 | 974 | ret = bdi_register_va(bdi, fmt, args); |
baf7a616 JK |
975 | va_end(args); |
976 | return ret; | |
977 | } | |
46100071 | 978 | EXPORT_SYMBOL(bdi_register); |
b2e8fb6e | 979 | |
df08c32c DW |
980 | int bdi_register_owner(struct backing_dev_info *bdi, struct device *owner) |
981 | { | |
982 | int rc; | |
983 | ||
7c4cc300 | 984 | rc = bdi_register(bdi, "%u:%u", MAJOR(owner->devt), MINOR(owner->devt)); |
df08c32c DW |
985 | if (rc) |
986 | return rc; | |
b6f8fec4 JK |
987 | /* Leaking owner reference... */ |
988 | WARN_ON(bdi->owner); | |
df08c32c DW |
989 | bdi->owner = owner; |
990 | get_device(owner); | |
991 | return 0; | |
992 | } | |
993 | EXPORT_SYMBOL(bdi_register_owner); | |
994 | ||
46100071 TH |
995 | /* |
996 | * Remove bdi from bdi_list, and ensure that it is no longer visible | |
997 | */ | |
998 | static void bdi_remove_from_list(struct backing_dev_info *bdi) | |
999 | { | |
1000 | spin_lock_bh(&bdi_lock); | |
34f8fe50 | 1001 | rb_erase(&bdi->rb_node, &bdi_tree); |
46100071 TH |
1002 | list_del_rcu(&bdi->bdi_list); |
1003 | spin_unlock_bh(&bdi_lock); | |
b2e8fb6e | 1004 | |
46100071 TH |
1005 | synchronize_rcu_expedited(); |
1006 | } | |
cf0ca9fe | 1007 | |
b02176f3 | 1008 | void bdi_unregister(struct backing_dev_info *bdi) |
b2e8fb6e | 1009 | { |
f0054bb1 TH |
1010 | /* make sure nobody finds us on the bdi_list anymore */ |
1011 | bdi_remove_from_list(bdi); | |
1012 | wb_shutdown(&bdi->wb); | |
b1c51afc | 1013 | cgwb_bdi_unregister(bdi); |
7a401a97 | 1014 | |
c4db59d3 CH |
1015 | if (bdi->dev) { |
1016 | bdi_debug_unregister(bdi); | |
1017 | device_unregister(bdi->dev); | |
1018 | bdi->dev = NULL; | |
1019 | } | |
df08c32c DW |
1020 | |
1021 | if (bdi->owner) { | |
1022 | put_device(bdi->owner); | |
1023 | bdi->owner = NULL; | |
1024 | } | |
b02176f3 | 1025 | } |
c4db59d3 | 1026 | |
d03f6cdc JK |
1027 | static void release_bdi(struct kref *ref) |
1028 | { | |
1029 | struct backing_dev_info *bdi = | |
1030 | container_of(ref, struct backing_dev_info, refcnt); | |
1031 | ||
5af110b2 JK |
1032 | if (test_bit(WB_registered, &bdi->wb.state)) |
1033 | bdi_unregister(bdi); | |
2e82b84c JK |
1034 | WARN_ON_ONCE(bdi->dev); |
1035 | wb_exit(&bdi->wb); | |
1036 | cgwb_bdi_exit(bdi); | |
d03f6cdc JK |
1037 | kfree(bdi); |
1038 | } | |
1039 | ||
1040 | void bdi_put(struct backing_dev_info *bdi) | |
1041 | { | |
1042 | kref_put(&bdi->refcnt, release_bdi); | |
1043 | } | |
62bf42ad | 1044 | EXPORT_SYMBOL(bdi_put); |
d03f6cdc | 1045 | |
3fcfab16 AM |
1046 | static wait_queue_head_t congestion_wqh[2] = { |
1047 | __WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[0]), | |
1048 | __WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[1]) | |
1049 | }; | |
ec8a6f26 | 1050 | static atomic_t nr_wb_congested[2]; |
3fcfab16 | 1051 | |
ec8a6f26 | 1052 | void clear_wb_congested(struct bdi_writeback_congested *congested, int sync) |
3fcfab16 | 1053 | { |
1faa16d2 | 1054 | wait_queue_head_t *wqh = &congestion_wqh[sync]; |
c877ef8a | 1055 | enum wb_congested_state bit; |
3fcfab16 | 1056 | |
4452226e | 1057 | bit = sync ? WB_sync_congested : WB_async_congested; |
ec8a6f26 TH |
1058 | if (test_and_clear_bit(bit, &congested->state)) |
1059 | atomic_dec(&nr_wb_congested[sync]); | |
4e857c58 | 1060 | smp_mb__after_atomic(); |
3fcfab16 AM |
1061 | if (waitqueue_active(wqh)) |
1062 | wake_up(wqh); | |
1063 | } | |
ec8a6f26 | 1064 | EXPORT_SYMBOL(clear_wb_congested); |
3fcfab16 | 1065 | |
ec8a6f26 | 1066 | void set_wb_congested(struct bdi_writeback_congested *congested, int sync) |
3fcfab16 | 1067 | { |
c877ef8a | 1068 | enum wb_congested_state bit; |
3fcfab16 | 1069 | |
4452226e | 1070 | bit = sync ? WB_sync_congested : WB_async_congested; |
ec8a6f26 TH |
1071 | if (!test_and_set_bit(bit, &congested->state)) |
1072 | atomic_inc(&nr_wb_congested[sync]); | |
3fcfab16 | 1073 | } |
ec8a6f26 | 1074 | EXPORT_SYMBOL(set_wb_congested); |
3fcfab16 AM |
1075 | |
1076 | /** | |
1077 | * congestion_wait - wait for a backing_dev to become uncongested | |
8aa7e847 | 1078 | * @sync: SYNC or ASYNC IO |
3fcfab16 AM |
1079 | * @timeout: timeout in jiffies |
1080 | * | |
1081 | * Waits for up to @timeout jiffies for a backing_dev (any backing_dev) to exit | |
1082 | * write congestion. If no backing_devs are congested then just wait for the | |
1083 | * next write to be completed. | |
1084 | */ | |
8aa7e847 | 1085 | long congestion_wait(int sync, long timeout) |
3fcfab16 AM |
1086 | { |
1087 | long ret; | |
52bb9198 | 1088 | unsigned long start = jiffies; |
3fcfab16 | 1089 | DEFINE_WAIT(wait); |
8aa7e847 | 1090 | wait_queue_head_t *wqh = &congestion_wqh[sync]; |
3fcfab16 AM |
1091 | |
1092 | prepare_to_wait(wqh, &wait, TASK_UNINTERRUPTIBLE); | |
1093 | ret = io_schedule_timeout(timeout); | |
1094 | finish_wait(wqh, &wait); | |
52bb9198 MG |
1095 | |
1096 | trace_writeback_congestion_wait(jiffies_to_usecs(timeout), | |
1097 | jiffies_to_usecs(jiffies - start)); | |
1098 | ||
3fcfab16 AM |
1099 | return ret; |
1100 | } | |
1101 | EXPORT_SYMBOL(congestion_wait); | |
04fbfdc1 | 1102 | |
0e093d99 | 1103 | /** |
599d0c95 | 1104 | * wait_iff_congested - Conditionally wait for a backing_dev to become uncongested or a pgdat to complete writes |
0e093d99 MG |
1105 | * @sync: SYNC or ASYNC IO |
1106 | * @timeout: timeout in jiffies | |
1107 | * | |
e3c1ac58 AR |
1108 | * In the event of a congested backing_dev (any backing_dev) this waits |
1109 | * for up to @timeout jiffies for either a BDI to exit congestion of the | |
1110 | * given @sync queue or a write to complete. | |
0e093d99 MG |
1111 | * |
1112 | * The return value is 0 if the sleep is for the full timeout. Otherwise, | |
1113 | * it is the number of jiffies that were still remaining when the function | |
1114 | * returned. return_value == timeout implies the function did not sleep. | |
1115 | */ | |
e3c1ac58 | 1116 | long wait_iff_congested(int sync, long timeout) |
0e093d99 MG |
1117 | { |
1118 | long ret; | |
1119 | unsigned long start = jiffies; | |
1120 | DEFINE_WAIT(wait); | |
1121 | wait_queue_head_t *wqh = &congestion_wqh[sync]; | |
1122 | ||
1123 | /* | |
e3c1ac58 | 1124 | * If there is no congestion, yield if necessary instead |
0e093d99 MG |
1125 | * of sleeping on the congestion queue |
1126 | */ | |
e3c1ac58 | 1127 | if (atomic_read(&nr_wb_congested[sync]) == 0) { |
ede37713 | 1128 | cond_resched(); |
599d0c95 | 1129 | |
0e093d99 MG |
1130 | /* In case we scheduled, work out time remaining */ |
1131 | ret = timeout - (jiffies - start); | |
1132 | if (ret < 0) | |
1133 | ret = 0; | |
1134 | ||
1135 | goto out; | |
1136 | } | |
1137 | ||
1138 | /* Sleep until uncongested or a write happens */ | |
1139 | prepare_to_wait(wqh, &wait, TASK_UNINTERRUPTIBLE); | |
1140 | ret = io_schedule_timeout(timeout); | |
1141 | finish_wait(wqh, &wait); | |
1142 | ||
1143 | out: | |
1144 | trace_writeback_wait_iff_congested(jiffies_to_usecs(timeout), | |
1145 | jiffies_to_usecs(jiffies - start)); | |
1146 | ||
1147 | return ret; | |
1148 | } | |
1149 | EXPORT_SYMBOL(wait_iff_congested); |