Commit | Line | Data |
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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 | } | |
ae82291e | 181 | BDI_SHOW(min_ratio, bdi->min_ratio / BDI_RATIO_SCALE) |
189d3c4a | 182 | |
ad3e6dab SR |
183 | static ssize_t min_ratio_fine_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); | |
187 | unsigned int ratio; | |
188 | ssize_t ret; | |
189 | ||
190 | ret = kstrtouint(buf, 10, &ratio); | |
191 | if (ret < 0) | |
192 | return ret; | |
193 | ||
194 | ret = bdi_set_min_ratio_no_scale(bdi, ratio); | |
195 | if (!ret) | |
196 | ret = count; | |
197 | ||
198 | return ret; | |
199 | } | |
200 | BDI_SHOW(min_ratio_fine, bdi->min_ratio) | |
201 | ||
a42dde04 PZ |
202 | static ssize_t max_ratio_store(struct device *dev, |
203 | struct device_attribute *attr, const char *buf, size_t count) | |
204 | { | |
205 | struct backing_dev_info *bdi = dev_get_drvdata(dev); | |
a42dde04 | 206 | unsigned int ratio; |
7034ed13 NJ |
207 | ssize_t ret; |
208 | ||
209 | ret = kstrtouint(buf, 10, &ratio); | |
210 | if (ret < 0) | |
211 | return ret; | |
212 | ||
213 | ret = bdi_set_max_ratio(bdi, ratio); | |
214 | if (!ret) | |
215 | ret = count; | |
a42dde04 | 216 | |
a42dde04 PZ |
217 | return ret; |
218 | } | |
ae82291e | 219 | BDI_SHOW(max_ratio, bdi->max_ratio / BDI_RATIO_SCALE) |
a42dde04 | 220 | |
bca52dcb SR |
221 | static ssize_t max_ratio_fine_store(struct device *dev, |
222 | struct device_attribute *attr, const char *buf, size_t count) | |
223 | { | |
224 | struct backing_dev_info *bdi = dev_get_drvdata(dev); | |
225 | unsigned int ratio; | |
226 | ssize_t ret; | |
227 | ||
228 | ret = kstrtouint(buf, 10, &ratio); | |
229 | if (ret < 0) | |
230 | return ret; | |
231 | ||
232 | ret = bdi_set_max_ratio_no_scale(bdi, ratio); | |
233 | if (!ret) | |
234 | ret = count; | |
235 | ||
236 | return ret; | |
237 | } | |
238 | BDI_SHOW(max_ratio_fine, bdi->max_ratio) | |
239 | ||
9c84819b SR |
240 | static ssize_t min_bytes_show(struct device *dev, |
241 | struct device_attribute *attr, | |
242 | char *buf) | |
243 | { | |
244 | struct backing_dev_info *bdi = dev_get_drvdata(dev); | |
245 | ||
246 | return sysfs_emit(buf, "%llu\n", bdi_get_min_bytes(bdi)); | |
247 | } | |
248 | ||
249 | static ssize_t min_bytes_store(struct device *dev, | |
250 | struct device_attribute *attr, const char *buf, size_t count) | |
251 | { | |
252 | struct backing_dev_info *bdi = dev_get_drvdata(dev); | |
253 | u64 bytes; | |
254 | ssize_t ret; | |
255 | ||
256 | ret = kstrtoull(buf, 10, &bytes); | |
257 | if (ret < 0) | |
258 | return ret; | |
259 | ||
260 | ret = bdi_set_min_bytes(bdi, bytes); | |
261 | if (!ret) | |
262 | ret = count; | |
263 | ||
264 | return ret; | |
265 | } | |
266 | DEVICE_ATTR_RW(min_bytes); | |
267 | ||
c56e049a SR |
268 | static ssize_t max_bytes_show(struct device *dev, |
269 | struct device_attribute *attr, | |
270 | char *buf) | |
271 | { | |
272 | struct backing_dev_info *bdi = dev_get_drvdata(dev); | |
273 | ||
274 | return sysfs_emit(buf, "%llu\n", bdi_get_max_bytes(bdi)); | |
275 | } | |
276 | ||
277 | static ssize_t max_bytes_store(struct device *dev, | |
278 | struct device_attribute *attr, const char *buf, size_t count) | |
279 | { | |
280 | struct backing_dev_info *bdi = dev_get_drvdata(dev); | |
281 | u64 bytes; | |
282 | ssize_t ret; | |
283 | ||
284 | ret = kstrtoull(buf, 10, &bytes); | |
285 | if (ret < 0) | |
286 | return ret; | |
287 | ||
288 | ret = bdi_set_max_bytes(bdi, bytes); | |
289 | if (!ret) | |
290 | ret = count; | |
291 | ||
292 | return ret; | |
293 | } | |
294 | DEVICE_ATTR_RW(max_bytes); | |
295 | ||
7d311cda DW |
296 | static ssize_t stable_pages_required_show(struct device *dev, |
297 | struct device_attribute *attr, | |
5e4c0d86 | 298 | char *buf) |
7d311cda | 299 | { |
1cb039f3 CH |
300 | dev_warn_once(dev, |
301 | "the stable_pages_required attribute has been removed. Use the stable_writes queue attribute instead.\n"); | |
5e4c0d86 | 302 | return sysfs_emit(buf, "%d\n", 0); |
7d311cda | 303 | } |
d9e1241e GKH |
304 | static DEVICE_ATTR_RO(stable_pages_required); |
305 | ||
27bbe9d4 SR |
306 | static ssize_t strict_limit_store(struct device *dev, |
307 | struct device_attribute *attr, const char *buf, size_t count) | |
308 | { | |
309 | struct backing_dev_info *bdi = dev_get_drvdata(dev); | |
310 | unsigned int strict_limit; | |
311 | ssize_t ret; | |
312 | ||
313 | ret = kstrtouint(buf, 10, &strict_limit); | |
314 | if (ret < 0) | |
315 | return ret; | |
316 | ||
317 | ret = bdi_set_strict_limit(bdi, strict_limit); | |
318 | if (!ret) | |
319 | ret = count; | |
320 | ||
321 | return ret; | |
322 | } | |
323 | ||
324 | static ssize_t strict_limit_show(struct device *dev, | |
325 | struct device_attribute *attr, char *buf) | |
326 | { | |
327 | struct backing_dev_info *bdi = dev_get_drvdata(dev); | |
328 | ||
329 | return sysfs_emit(buf, "%d\n", | |
330 | !!(bdi->capabilities & BDI_CAP_STRICTLIMIT)); | |
331 | } | |
332 | static DEVICE_ATTR_RW(strict_limit); | |
333 | ||
d9e1241e GKH |
334 | static struct attribute *bdi_dev_attrs[] = { |
335 | &dev_attr_read_ahead_kb.attr, | |
336 | &dev_attr_min_ratio.attr, | |
ad3e6dab | 337 | &dev_attr_min_ratio_fine.attr, |
d9e1241e | 338 | &dev_attr_max_ratio.attr, |
bca52dcb | 339 | &dev_attr_max_ratio_fine.attr, |
9c84819b | 340 | &dev_attr_min_bytes.attr, |
c56e049a | 341 | &dev_attr_max_bytes.attr, |
d9e1241e | 342 | &dev_attr_stable_pages_required.attr, |
27bbe9d4 | 343 | &dev_attr_strict_limit.attr, |
d9e1241e | 344 | NULL, |
cf0ca9fe | 345 | }; |
d9e1241e | 346 | ATTRIBUTE_GROUPS(bdi_dev); |
cf0ca9fe PZ |
347 | |
348 | static __init int bdi_class_init(void) | |
349 | { | |
350 | bdi_class = class_create(THIS_MODULE, "bdi"); | |
14421453 AB |
351 | if (IS_ERR(bdi_class)) |
352 | return PTR_ERR(bdi_class); | |
353 | ||
d9e1241e | 354 | bdi_class->dev_groups = bdi_dev_groups; |
76f1418b | 355 | bdi_debug_init(); |
d03f6cdc | 356 | |
cf0ca9fe PZ |
357 | return 0; |
358 | } | |
76f1418b | 359 | postcore_initcall(bdi_class_init); |
cf0ca9fe | 360 | |
26160158 JA |
361 | static int __init default_bdi_init(void) |
362 | { | |
a2b90f11 MW |
363 | bdi_wq = alloc_workqueue("writeback", WQ_MEM_RECLAIM | WQ_UNBOUND | |
364 | WQ_SYSFS, 0); | |
839a8e86 TH |
365 | if (!bdi_wq) |
366 | return -ENOMEM; | |
4bca7e80 | 367 | return 0; |
26160158 JA |
368 | } |
369 | subsys_initcall(default_bdi_init); | |
370 | ||
6467716a | 371 | /* |
f0054bb1 | 372 | * This function is used when the first inode for this wb is marked dirty. It |
6467716a AB |
373 | * wakes-up the corresponding bdi thread which should then take care of the |
374 | * periodic background write-out of dirty inodes. Since the write-out would | |
375 | * starts only 'dirty_writeback_interval' centisecs from now anyway, we just | |
376 | * set up a timer which wakes the bdi thread up later. | |
377 | * | |
378 | * Note, we wouldn't bother setting up the timer, but this function is on the | |
379 | * fast-path (used by '__mark_inode_dirty()'), so we save few context switches | |
380 | * by delaying the wake-up. | |
6ca738d6 DB |
381 | * |
382 | * We have to be careful not to postpone flush work if it is scheduled for | |
383 | * earlier. Thus we use queue_delayed_work(). | |
6467716a | 384 | */ |
f0054bb1 | 385 | void wb_wakeup_delayed(struct bdi_writeback *wb) |
6467716a AB |
386 | { |
387 | unsigned long timeout; | |
388 | ||
389 | timeout = msecs_to_jiffies(dirty_writeback_interval * 10); | |
f87904c0 | 390 | spin_lock_irq(&wb->work_lock); |
f0054bb1 TH |
391 | if (test_bit(WB_registered, &wb->state)) |
392 | queue_delayed_work(bdi_wq, &wb->dwork, timeout); | |
f87904c0 | 393 | spin_unlock_irq(&wb->work_lock); |
03ba3782 JA |
394 | } |
395 | ||
45a2966f JK |
396 | static void wb_update_bandwidth_workfn(struct work_struct *work) |
397 | { | |
398 | struct bdi_writeback *wb = container_of(to_delayed_work(work), | |
399 | struct bdi_writeback, bw_dwork); | |
400 | ||
401 | wb_update_bandwidth(wb); | |
402 | } | |
403 | ||
cfc4ba53 | 404 | /* |
a88a341a | 405 | * Initial write bandwidth: 100 MB/s |
cfc4ba53 | 406 | */ |
a88a341a | 407 | #define INIT_BW (100 << (20 - PAGE_SHIFT)) |
cfc4ba53 | 408 | |
8395cd9f | 409 | static int wb_init(struct bdi_writeback *wb, struct backing_dev_info *bdi, |
8c911f3d | 410 | gfp_t gfp) |
cf0ca9fe | 411 | { |
93f78d88 | 412 | int i, err; |
cf0ca9fe | 413 | |
6467716a | 414 | memset(wb, 0, sizeof(*wb)); |
f1d0b063 | 415 | |
6467716a AB |
416 | wb->bdi = bdi; |
417 | wb->last_old_flush = jiffies; | |
418 | INIT_LIST_HEAD(&wb->b_dirty); | |
419 | INIT_LIST_HEAD(&wb->b_io); | |
420 | INIT_LIST_HEAD(&wb->b_more_io); | |
0ae45f63 | 421 | INIT_LIST_HEAD(&wb->b_dirty_time); |
f758eeab | 422 | spin_lock_init(&wb->list_lock); |
66f3b8e2 | 423 | |
633a2abb | 424 | atomic_set(&wb->writeback_inodes, 0); |
a88a341a TH |
425 | wb->bw_time_stamp = jiffies; |
426 | wb->balanced_dirty_ratelimit = INIT_BW; | |
427 | wb->dirty_ratelimit = INIT_BW; | |
428 | wb->write_bandwidth = INIT_BW; | |
429 | wb->avg_write_bandwidth = INIT_BW; | |
cf0ca9fe | 430 | |
f0054bb1 TH |
431 | spin_lock_init(&wb->work_lock); |
432 | INIT_LIST_HEAD(&wb->work_list); | |
433 | INIT_DELAYED_WORK(&wb->dwork, wb_workfn); | |
45a2966f | 434 | INIT_DELAYED_WORK(&wb->bw_dwork, wb_update_bandwidth_workfn); |
b57d74af | 435 | wb->dirty_sleep = jiffies; |
c284de61 | 436 | |
8395cd9f | 437 | err = fprop_local_init_percpu(&wb->completions, gfp); |
a88a341a | 438 | if (err) |
efee1713 | 439 | return err; |
c284de61 | 440 | |
93f78d88 | 441 | for (i = 0; i < NR_WB_STAT_ITEMS; i++) { |
8395cd9f | 442 | err = percpu_counter_init(&wb->stat[i], 0, gfp); |
a13f35e8 TH |
443 | if (err) |
444 | goto out_destroy_stat; | |
93f78d88 | 445 | } |
cf0ca9fe | 446 | |
93f78d88 | 447 | return 0; |
a13f35e8 TH |
448 | |
449 | out_destroy_stat: | |
078c6c3a | 450 | while (i--) |
a13f35e8 TH |
451 | percpu_counter_destroy(&wb->stat[i]); |
452 | fprop_local_destroy_percpu(&wb->completions); | |
a13f35e8 | 453 | return err; |
cf0ca9fe | 454 | } |
cf0ca9fe | 455 | |
e8cb72b3 JK |
456 | static void cgwb_remove_from_bdi_list(struct bdi_writeback *wb); |
457 | ||
03ba3782 JA |
458 | /* |
459 | * Remove bdi from the global list and shutdown any threads we have running | |
460 | */ | |
46100071 | 461 | static void wb_shutdown(struct bdi_writeback *wb) |
66f3b8e2 | 462 | { |
c4db59d3 | 463 | /* Make sure nobody queues further work */ |
f87904c0 | 464 | spin_lock_irq(&wb->work_lock); |
46100071 | 465 | if (!test_and_clear_bit(WB_registered, &wb->state)) { |
f87904c0 | 466 | spin_unlock_irq(&wb->work_lock); |
03ba3782 | 467 | return; |
c4db59d3 | 468 | } |
f87904c0 | 469 | spin_unlock_irq(&wb->work_lock); |
03ba3782 | 470 | |
e8cb72b3 | 471 | cgwb_remove_from_bdi_list(wb); |
03ba3782 | 472 | /* |
46100071 TH |
473 | * Drain work list and shutdown the delayed_work. !WB_registered |
474 | * tells wb_workfn() that @wb is dying and its work_list needs to | |
475 | * be drained no matter what. | |
03ba3782 | 476 | */ |
46100071 TH |
477 | mod_delayed_work(bdi_wq, &wb->dwork, 0); |
478 | flush_delayed_work(&wb->dwork); | |
479 | WARN_ON(!list_empty(&wb->work_list)); | |
45a2966f | 480 | flush_delayed_work(&wb->bw_dwork); |
46100071 TH |
481 | } |
482 | ||
f0054bb1 | 483 | static void wb_exit(struct bdi_writeback *wb) |
93f78d88 TH |
484 | { |
485 | int i; | |
486 | ||
487 | WARN_ON(delayed_work_pending(&wb->dwork)); | |
488 | ||
489 | for (i = 0; i < NR_WB_STAT_ITEMS; i++) | |
490 | percpu_counter_destroy(&wb->stat[i]); | |
6467716a | 491 | |
a88a341a TH |
492 | fprop_local_destroy_percpu(&wb->completions); |
493 | } | |
e98be2d5 | 494 | |
52ebea74 TH |
495 | #ifdef CONFIG_CGROUP_WRITEBACK |
496 | ||
497 | #include <linux/memcontrol.h> | |
498 | ||
499 | /* | |
c22d70a1 RG |
500 | * cgwb_lock protects bdi->cgwb_tree, blkcg->cgwb_list, offline_cgwbs and |
501 | * memcg->cgwb_list. bdi->cgwb_tree is also RCU protected. | |
52ebea74 TH |
502 | */ |
503 | static DEFINE_SPINLOCK(cgwb_lock); | |
f1834646 | 504 | static struct workqueue_struct *cgwb_release_wq; |
52ebea74 | 505 | |
c22d70a1 RG |
506 | static LIST_HEAD(offline_cgwbs); |
507 | static void cleanup_offline_cgwbs_workfn(struct work_struct *work); | |
508 | static DECLARE_WORK(cleanup_offline_cgwbs_work, cleanup_offline_cgwbs_workfn); | |
509 | ||
52ebea74 TH |
510 | static void cgwb_release_workfn(struct work_struct *work) |
511 | { | |
512 | struct bdi_writeback *wb = container_of(work, struct bdi_writeback, | |
513 | release_work); | |
efee1713 | 514 | struct backing_dev_info *bdi = wb->bdi; |
52ebea74 | 515 | |
3ee7e869 | 516 | mutex_lock(&wb->bdi->cgwb_release_mutex); |
52ebea74 TH |
517 | wb_shutdown(wb); |
518 | ||
519 | css_put(wb->memcg_css); | |
520 | css_put(wb->blkcg_css); | |
3ee7e869 | 521 | mutex_unlock(&wb->bdi->cgwb_release_mutex); |
52ebea74 | 522 | |
d866dbf6 | 523 | /* triggers blkg destruction if no online users left */ |
397c9f46 | 524 | blkcg_unpin_online(wb->blkcg_css); |
59b57717 | 525 | |
841710aa | 526 | fprop_local_destroy_percpu(&wb->memcg_completions); |
c22d70a1 RG |
527 | |
528 | spin_lock_irq(&cgwb_lock); | |
529 | list_del(&wb->offline_node); | |
530 | spin_unlock_irq(&cgwb_lock); | |
531 | ||
b43a9e76 | 532 | percpu_ref_exit(&wb->refcnt); |
52ebea74 | 533 | wb_exit(wb); |
efee1713 | 534 | bdi_put(bdi); |
f3b6a6df | 535 | WARN_ON_ONCE(!list_empty(&wb->b_attached)); |
52ebea74 | 536 | kfree_rcu(wb, rcu); |
52ebea74 TH |
537 | } |
538 | ||
539 | static void cgwb_release(struct percpu_ref *refcnt) | |
540 | { | |
541 | struct bdi_writeback *wb = container_of(refcnt, struct bdi_writeback, | |
542 | refcnt); | |
f1834646 | 543 | queue_work(cgwb_release_wq, &wb->release_work); |
52ebea74 TH |
544 | } |
545 | ||
546 | static void cgwb_kill(struct bdi_writeback *wb) | |
547 | { | |
548 | lockdep_assert_held(&cgwb_lock); | |
549 | ||
550 | WARN_ON(!radix_tree_delete(&wb->bdi->cgwb_tree, wb->memcg_css->id)); | |
551 | list_del(&wb->memcg_node); | |
552 | list_del(&wb->blkcg_node); | |
c22d70a1 | 553 | list_add(&wb->offline_node, &offline_cgwbs); |
52ebea74 TH |
554 | percpu_ref_kill(&wb->refcnt); |
555 | } | |
556 | ||
e8cb72b3 JK |
557 | static void cgwb_remove_from_bdi_list(struct bdi_writeback *wb) |
558 | { | |
559 | spin_lock_irq(&cgwb_lock); | |
560 | list_del_rcu(&wb->bdi_node); | |
561 | spin_unlock_irq(&cgwb_lock); | |
562 | } | |
563 | ||
52ebea74 TH |
564 | static int cgwb_create(struct backing_dev_info *bdi, |
565 | struct cgroup_subsys_state *memcg_css, gfp_t gfp) | |
566 | { | |
567 | struct mem_cgroup *memcg; | |
568 | struct cgroup_subsys_state *blkcg_css; | |
52ebea74 TH |
569 | struct list_head *memcg_cgwb_list, *blkcg_cgwb_list; |
570 | struct bdi_writeback *wb; | |
571 | unsigned long flags; | |
572 | int ret = 0; | |
573 | ||
574 | memcg = mem_cgroup_from_css(memcg_css); | |
c165b3e3 | 575 | blkcg_css = cgroup_get_e_css(memcg_css->cgroup, &io_cgrp_subsys); |
9ccc3617 | 576 | memcg_cgwb_list = &memcg->cgwb_list; |
dec223c9 | 577 | blkcg_cgwb_list = blkcg_get_cgwb_list(blkcg_css); |
52ebea74 TH |
578 | |
579 | /* look up again under lock and discard on blkcg mismatch */ | |
580 | spin_lock_irqsave(&cgwb_lock, flags); | |
581 | wb = radix_tree_lookup(&bdi->cgwb_tree, memcg_css->id); | |
582 | if (wb && wb->blkcg_css != blkcg_css) { | |
583 | cgwb_kill(wb); | |
584 | wb = NULL; | |
585 | } | |
586 | spin_unlock_irqrestore(&cgwb_lock, flags); | |
587 | if (wb) | |
588 | goto out_put; | |
589 | ||
590 | /* need to create a new one */ | |
591 | wb = kmalloc(sizeof(*wb), gfp); | |
0b045bd1 CJ |
592 | if (!wb) { |
593 | ret = -ENOMEM; | |
594 | goto out_put; | |
595 | } | |
52ebea74 | 596 | |
8c911f3d | 597 | ret = wb_init(wb, bdi, gfp); |
52ebea74 TH |
598 | if (ret) |
599 | goto err_free; | |
600 | ||
601 | ret = percpu_ref_init(&wb->refcnt, cgwb_release, 0, gfp); | |
602 | if (ret) | |
603 | goto err_wb_exit; | |
604 | ||
841710aa TH |
605 | ret = fprop_local_init_percpu(&wb->memcg_completions, gfp); |
606 | if (ret) | |
607 | goto err_ref_exit; | |
608 | ||
52ebea74 TH |
609 | wb->memcg_css = memcg_css; |
610 | wb->blkcg_css = blkcg_css; | |
f3b6a6df | 611 | INIT_LIST_HEAD(&wb->b_attached); |
52ebea74 TH |
612 | INIT_WORK(&wb->release_work, cgwb_release_workfn); |
613 | set_bit(WB_registered, &wb->state); | |
efee1713 | 614 | bdi_get(bdi); |
03ba3782 JA |
615 | |
616 | /* | |
52ebea74 TH |
617 | * The root wb determines the registered state of the whole bdi and |
618 | * memcg_cgwb_list and blkcg_cgwb_list's next pointers indicate | |
619 | * whether they're still online. Don't link @wb if any is dead. | |
620 | * See wb_memcg_offline() and wb_blkcg_offline(). | |
03ba3782 | 621 | */ |
52ebea74 TH |
622 | ret = -ENODEV; |
623 | spin_lock_irqsave(&cgwb_lock, flags); | |
624 | if (test_bit(WB_registered, &bdi->wb.state) && | |
625 | blkcg_cgwb_list->next && memcg_cgwb_list->next) { | |
626 | /* we might have raced another instance of this function */ | |
627 | ret = radix_tree_insert(&bdi->cgwb_tree, memcg_css->id, wb); | |
628 | if (!ret) { | |
b817525a | 629 | list_add_tail_rcu(&wb->bdi_node, &bdi->wb_list); |
52ebea74 TH |
630 | list_add(&wb->memcg_node, memcg_cgwb_list); |
631 | list_add(&wb->blkcg_node, blkcg_cgwb_list); | |
397c9f46 | 632 | blkcg_pin_online(blkcg_css); |
52ebea74 TH |
633 | css_get(memcg_css); |
634 | css_get(blkcg_css); | |
635 | } | |
636 | } | |
637 | spin_unlock_irqrestore(&cgwb_lock, flags); | |
638 | if (ret) { | |
639 | if (ret == -EEXIST) | |
640 | ret = 0; | |
a13f35e8 | 641 | goto err_fprop_exit; |
52ebea74 TH |
642 | } |
643 | goto out_put; | |
644 | ||
841710aa | 645 | err_fprop_exit: |
efee1713 | 646 | bdi_put(bdi); |
841710aa | 647 | fprop_local_destroy_percpu(&wb->memcg_completions); |
52ebea74 TH |
648 | err_ref_exit: |
649 | percpu_ref_exit(&wb->refcnt); | |
650 | err_wb_exit: | |
651 | wb_exit(wb); | |
652 | err_free: | |
653 | kfree(wb); | |
654 | out_put: | |
655 | css_put(blkcg_css); | |
656 | return ret; | |
66f3b8e2 JA |
657 | } |
658 | ||
52ebea74 | 659 | /** |
ed288dc0 | 660 | * wb_get_lookup - get wb for a given memcg |
52ebea74 TH |
661 | * @bdi: target bdi |
662 | * @memcg_css: cgroup_subsys_state of the target memcg (must have positive ref) | |
52ebea74 | 663 | * |
ed288dc0 TH |
664 | * Try to get the wb for @memcg_css on @bdi. The returned wb has its |
665 | * refcount incremented. | |
52ebea74 TH |
666 | * |
667 | * This function uses css_get() on @memcg_css and thus expects its refcnt | |
668 | * to be positive on invocation. IOW, rcu_read_lock() protection on | |
669 | * @memcg_css isn't enough. try_get it before calling this function. | |
670 | * | |
671 | * A wb is keyed by its associated memcg. As blkcg implicitly enables | |
672 | * memcg on the default hierarchy, memcg association is guaranteed to be | |
673 | * more specific (equal or descendant to the associated blkcg) and thus can | |
674 | * identify both the memcg and blkcg associations. | |
675 | * | |
676 | * Because the blkcg associated with a memcg may change as blkcg is enabled | |
677 | * and disabled closer to root in the hierarchy, each wb keeps track of | |
678 | * both the memcg and blkcg associated with it and verifies the blkcg on | |
679 | * each lookup. On mismatch, the existing wb is discarded and a new one is | |
680 | * created. | |
681 | */ | |
ed288dc0 TH |
682 | struct bdi_writeback *wb_get_lookup(struct backing_dev_info *bdi, |
683 | struct cgroup_subsys_state *memcg_css) | |
684 | { | |
685 | struct bdi_writeback *wb; | |
686 | ||
687 | if (!memcg_css->parent) | |
688 | return &bdi->wb; | |
689 | ||
690 | rcu_read_lock(); | |
691 | wb = radix_tree_lookup(&bdi->cgwb_tree, memcg_css->id); | |
692 | if (wb) { | |
693 | struct cgroup_subsys_state *blkcg_css; | |
694 | ||
695 | /* see whether the blkcg association has changed */ | |
696 | blkcg_css = cgroup_get_e_css(memcg_css->cgroup, &io_cgrp_subsys); | |
697 | if (unlikely(wb->blkcg_css != blkcg_css || !wb_tryget(wb))) | |
698 | wb = NULL; | |
699 | css_put(blkcg_css); | |
700 | } | |
701 | rcu_read_unlock(); | |
702 | ||
703 | return wb; | |
704 | } | |
705 | ||
706 | /** | |
707 | * wb_get_create - get wb for a given memcg, create if necessary | |
708 | * @bdi: target bdi | |
709 | * @memcg_css: cgroup_subsys_state of the target memcg (must have positive ref) | |
710 | * @gfp: allocation mask to use | |
711 | * | |
712 | * Try to get the wb for @memcg_css on @bdi. If it doesn't exist, try to | |
713 | * create one. See wb_get_lookup() for more details. | |
714 | */ | |
52ebea74 TH |
715 | struct bdi_writeback *wb_get_create(struct backing_dev_info *bdi, |
716 | struct cgroup_subsys_state *memcg_css, | |
717 | gfp_t gfp) | |
6467716a | 718 | { |
52ebea74 TH |
719 | struct bdi_writeback *wb; |
720 | ||
c1ca59a1 | 721 | might_alloc(gfp); |
52ebea74 TH |
722 | |
723 | if (!memcg_css->parent) | |
724 | return &bdi->wb; | |
725 | ||
726 | do { | |
ed288dc0 | 727 | wb = wb_get_lookup(bdi, memcg_css); |
52ebea74 TH |
728 | } while (!wb && !cgwb_create(bdi, memcg_css, gfp)); |
729 | ||
730 | return wb; | |
731 | } | |
6467716a | 732 | |
a13f35e8 | 733 | static int cgwb_bdi_init(struct backing_dev_info *bdi) |
52ebea74 | 734 | { |
a13f35e8 TH |
735 | int ret; |
736 | ||
52ebea74 | 737 | INIT_RADIX_TREE(&bdi->cgwb_tree, GFP_ATOMIC); |
3ee7e869 | 738 | mutex_init(&bdi->cgwb_release_mutex); |
7fc5854f | 739 | init_rwsem(&bdi->wb_switch_rwsem); |
a13f35e8 | 740 | |
8c911f3d | 741 | ret = wb_init(&bdi->wb, bdi, GFP_KERNEL); |
a13f35e8 | 742 | if (!ret) { |
7d828602 | 743 | bdi->wb.memcg_css = &root_mem_cgroup->css; |
a13f35e8 TH |
744 | bdi->wb.blkcg_css = blkcg_root_css; |
745 | } | |
746 | return ret; | |
6467716a AB |
747 | } |
748 | ||
b1c51afc | 749 | static void cgwb_bdi_unregister(struct backing_dev_info *bdi) |
52ebea74 TH |
750 | { |
751 | struct radix_tree_iter iter; | |
752 | void **slot; | |
5318ce7d | 753 | struct bdi_writeback *wb; |
52ebea74 TH |
754 | |
755 | WARN_ON(test_bit(WB_registered, &bdi->wb.state)); | |
756 | ||
757 | spin_lock_irq(&cgwb_lock); | |
758 | radix_tree_for_each_slot(slot, &bdi->cgwb_tree, &iter, 0) | |
759 | cgwb_kill(*slot); | |
3ee7e869 | 760 | spin_unlock_irq(&cgwb_lock); |
5318ce7d | 761 | |
3ee7e869 JK |
762 | mutex_lock(&bdi->cgwb_release_mutex); |
763 | spin_lock_irq(&cgwb_lock); | |
5318ce7d JK |
764 | while (!list_empty(&bdi->wb_list)) { |
765 | wb = list_first_entry(&bdi->wb_list, struct bdi_writeback, | |
766 | bdi_node); | |
767 | spin_unlock_irq(&cgwb_lock); | |
768 | wb_shutdown(wb); | |
769 | spin_lock_irq(&cgwb_lock); | |
770 | } | |
52ebea74 | 771 | spin_unlock_irq(&cgwb_lock); |
3ee7e869 | 772 | mutex_unlock(&bdi->cgwb_release_mutex); |
52ebea74 TH |
773 | } |
774 | ||
c22d70a1 RG |
775 | /* |
776 | * cleanup_offline_cgwbs_workfn - try to release dying cgwbs | |
777 | * | |
778 | * Try to release dying cgwbs by switching attached inodes to the nearest | |
779 | * living ancestor's writeback. Processed wbs are placed at the end | |
780 | * of the list to guarantee the forward progress. | |
781 | */ | |
782 | static void cleanup_offline_cgwbs_workfn(struct work_struct *work) | |
783 | { | |
784 | struct bdi_writeback *wb; | |
785 | LIST_HEAD(processed); | |
786 | ||
787 | spin_lock_irq(&cgwb_lock); | |
788 | ||
789 | while (!list_empty(&offline_cgwbs)) { | |
790 | wb = list_first_entry(&offline_cgwbs, struct bdi_writeback, | |
791 | offline_node); | |
792 | list_move(&wb->offline_node, &processed); | |
793 | ||
794 | /* | |
795 | * If wb is dirty, cleaning up the writeback by switching | |
796 | * attached inodes will result in an effective removal of any | |
797 | * bandwidth restrictions, which isn't the goal. Instead, | |
798 | * it can be postponed until the next time, when all io | |
799 | * will be likely completed. If in the meantime some inodes | |
800 | * will get re-dirtied, they should be eventually switched to | |
801 | * a new cgwb. | |
802 | */ | |
803 | if (wb_has_dirty_io(wb)) | |
804 | continue; | |
805 | ||
806 | if (!wb_tryget(wb)) | |
807 | continue; | |
808 | ||
809 | spin_unlock_irq(&cgwb_lock); | |
810 | while (cleanup_offline_cgwb(wb)) | |
811 | cond_resched(); | |
812 | spin_lock_irq(&cgwb_lock); | |
813 | ||
814 | wb_put(wb); | |
815 | } | |
816 | ||
817 | if (!list_empty(&processed)) | |
818 | list_splice_tail(&processed, &offline_cgwbs); | |
819 | ||
820 | spin_unlock_irq(&cgwb_lock); | |
821 | } | |
822 | ||
52ebea74 TH |
823 | /** |
824 | * wb_memcg_offline - kill all wb's associated with a memcg being offlined | |
825 | * @memcg: memcg being offlined | |
826 | * | |
827 | * Also prevents creation of any new wb's associated with @memcg. | |
e98be2d5 | 828 | */ |
52ebea74 TH |
829 | void wb_memcg_offline(struct mem_cgroup *memcg) |
830 | { | |
9ccc3617 | 831 | struct list_head *memcg_cgwb_list = &memcg->cgwb_list; |
52ebea74 TH |
832 | struct bdi_writeback *wb, *next; |
833 | ||
834 | spin_lock_irq(&cgwb_lock); | |
835 | list_for_each_entry_safe(wb, next, memcg_cgwb_list, memcg_node) | |
836 | cgwb_kill(wb); | |
837 | memcg_cgwb_list->next = NULL; /* prevent new wb's */ | |
838 | spin_unlock_irq(&cgwb_lock); | |
c22d70a1 RG |
839 | |
840 | queue_work(system_unbound_wq, &cleanup_offline_cgwbs_work); | |
52ebea74 TH |
841 | } |
842 | ||
843 | /** | |
844 | * wb_blkcg_offline - kill all wb's associated with a blkcg being offlined | |
dec223c9 | 845 | * @css: blkcg being offlined |
52ebea74 TH |
846 | * |
847 | * Also prevents creation of any new wb's associated with @blkcg. | |
848 | */ | |
dec223c9 | 849 | void wb_blkcg_offline(struct cgroup_subsys_state *css) |
52ebea74 | 850 | { |
52ebea74 | 851 | struct bdi_writeback *wb, *next; |
dec223c9 | 852 | struct list_head *list = blkcg_get_cgwb_list(css); |
52ebea74 TH |
853 | |
854 | spin_lock_irq(&cgwb_lock); | |
dec223c9 | 855 | list_for_each_entry_safe(wb, next, list, blkcg_node) |
52ebea74 | 856 | cgwb_kill(wb); |
dec223c9 | 857 | list->next = NULL; /* prevent new wb's */ |
52ebea74 TH |
858 | spin_unlock_irq(&cgwb_lock); |
859 | } | |
860 | ||
e8cb72b3 JK |
861 | static void cgwb_bdi_register(struct backing_dev_info *bdi) |
862 | { | |
863 | spin_lock_irq(&cgwb_lock); | |
864 | list_add_tail_rcu(&bdi->wb.bdi_node, &bdi->wb_list); | |
865 | spin_unlock_irq(&cgwb_lock); | |
866 | } | |
867 | ||
f1834646 TH |
868 | static int __init cgwb_init(void) |
869 | { | |
870 | /* | |
871 | * There can be many concurrent release work items overwhelming | |
872 | * system_wq. Put them in a separate wq and limit concurrency. | |
873 | * There's no point in executing many of these in parallel. | |
874 | */ | |
875 | cgwb_release_wq = alloc_workqueue("cgwb_release", 0, 1); | |
876 | if (!cgwb_release_wq) | |
877 | return -ENOMEM; | |
878 | ||
879 | return 0; | |
880 | } | |
881 | subsys_initcall(cgwb_init); | |
882 | ||
52ebea74 TH |
883 | #else /* CONFIG_CGROUP_WRITEBACK */ |
884 | ||
a13f35e8 TH |
885 | static int cgwb_bdi_init(struct backing_dev_info *bdi) |
886 | { | |
8c911f3d | 887 | return wb_init(&bdi->wb, bdi, GFP_KERNEL); |
a13f35e8 TH |
888 | } |
889 | ||
b1c51afc | 890 | static void cgwb_bdi_unregister(struct backing_dev_info *bdi) { } |
df23de55 | 891 | |
e8cb72b3 JK |
892 | static void cgwb_bdi_register(struct backing_dev_info *bdi) |
893 | { | |
894 | list_add_tail_rcu(&bdi->wb.bdi_node, &bdi->wb_list); | |
895 | } | |
896 | ||
897 | static void cgwb_remove_from_bdi_list(struct bdi_writeback *wb) | |
898 | { | |
899 | list_del_rcu(&wb->bdi_node); | |
900 | } | |
901 | ||
52ebea74 | 902 | #endif /* CONFIG_CGROUP_WRITEBACK */ |
e98be2d5 | 903 | |
4bca7e80 | 904 | int bdi_init(struct backing_dev_info *bdi) |
b2e8fb6e | 905 | { |
cf0ca9fe PZ |
906 | bdi->dev = NULL; |
907 | ||
d03f6cdc | 908 | kref_init(&bdi->refcnt); |
189d3c4a | 909 | bdi->min_ratio = 0; |
ae82291e | 910 | bdi->max_ratio = 100 * BDI_RATIO_SCALE; |
eb608e3a | 911 | bdi->max_prop_frac = FPROP_FRAC_BASE; |
66f3b8e2 | 912 | INIT_LIST_HEAD(&bdi->bdi_list); |
b817525a | 913 | INIT_LIST_HEAD(&bdi->wb_list); |
cc395d7f | 914 | init_waitqueue_head(&bdi->wb_waitq); |
03ba3782 | 915 | |
3083da7b | 916 | return cgwb_bdi_init(bdi); |
b2e8fb6e | 917 | } |
e98be2d5 | 918 | |
aef33c2f | 919 | struct backing_dev_info *bdi_alloc(int node_id) |
d03f6cdc JK |
920 | { |
921 | struct backing_dev_info *bdi; | |
922 | ||
aef33c2f | 923 | bdi = kzalloc_node(sizeof(*bdi), GFP_KERNEL, node_id); |
d03f6cdc JK |
924 | if (!bdi) |
925 | return NULL; | |
926 | ||
927 | if (bdi_init(bdi)) { | |
928 | kfree(bdi); | |
929 | return NULL; | |
930 | } | |
f56753ac | 931 | bdi->capabilities = BDI_CAP_WRITEBACK | BDI_CAP_WRITEBACK_ACCT; |
55b2598e CH |
932 | bdi->ra_pages = VM_READAHEAD_PAGES; |
933 | bdi->io_pages = VM_READAHEAD_PAGES; | |
5ed964f8 | 934 | timer_setup(&bdi->laptop_mode_wb_timer, laptop_mode_timer_fn, 0); |
d03f6cdc JK |
935 | return bdi; |
936 | } | |
aef33c2f | 937 | EXPORT_SYMBOL(bdi_alloc); |
d03f6cdc | 938 | |
34f8fe50 TH |
939 | static struct rb_node **bdi_lookup_rb_node(u64 id, struct rb_node **parentp) |
940 | { | |
941 | struct rb_node **p = &bdi_tree.rb_node; | |
942 | struct rb_node *parent = NULL; | |
943 | struct backing_dev_info *bdi; | |
944 | ||
945 | lockdep_assert_held(&bdi_lock); | |
946 | ||
947 | while (*p) { | |
948 | parent = *p; | |
949 | bdi = rb_entry(parent, struct backing_dev_info, rb_node); | |
950 | ||
951 | if (bdi->id > id) | |
952 | p = &(*p)->rb_left; | |
953 | else if (bdi->id < id) | |
954 | p = &(*p)->rb_right; | |
955 | else | |
956 | break; | |
957 | } | |
958 | ||
959 | if (parentp) | |
960 | *parentp = parent; | |
961 | return p; | |
962 | } | |
963 | ||
964 | /** | |
965 | * bdi_get_by_id - lookup and get bdi from its id | |
966 | * @id: bdi id to lookup | |
967 | * | |
968 | * Find bdi matching @id and get it. Returns NULL if the matching bdi | |
969 | * doesn't exist or is already unregistered. | |
970 | */ | |
971 | struct backing_dev_info *bdi_get_by_id(u64 id) | |
972 | { | |
973 | struct backing_dev_info *bdi = NULL; | |
974 | struct rb_node **p; | |
975 | ||
976 | spin_lock_bh(&bdi_lock); | |
977 | p = bdi_lookup_rb_node(id, NULL); | |
978 | if (*p) { | |
979 | bdi = rb_entry(*p, struct backing_dev_info, rb_node); | |
980 | bdi_get(bdi); | |
981 | } | |
982 | spin_unlock_bh(&bdi_lock); | |
983 | ||
984 | return bdi; | |
985 | } | |
986 | ||
7c4cc300 | 987 | int bdi_register_va(struct backing_dev_info *bdi, const char *fmt, va_list args) |
46100071 | 988 | { |
46100071 | 989 | struct device *dev; |
34f8fe50 | 990 | struct rb_node *parent, **p; |
e98be2d5 | 991 | |
46100071 TH |
992 | if (bdi->dev) /* The driver needs to use separate queues per device */ |
993 | return 0; | |
e98be2d5 | 994 | |
6bd87eec CH |
995 | vsnprintf(bdi->dev_name, sizeof(bdi->dev_name), fmt, args); |
996 | dev = device_create(bdi_class, NULL, MKDEV(0, 0), bdi, bdi->dev_name); | |
46100071 TH |
997 | if (IS_ERR(dev)) |
998 | return PTR_ERR(dev); | |
04fbfdc1 | 999 | |
e8cb72b3 | 1000 | cgwb_bdi_register(bdi); |
46100071 | 1001 | bdi->dev = dev; |
b2e8fb6e | 1002 | |
6d0e4827 | 1003 | bdi_debug_register(bdi, dev_name(dev)); |
46100071 TH |
1004 | set_bit(WB_registered, &bdi->wb.state); |
1005 | ||
1006 | spin_lock_bh(&bdi_lock); | |
34f8fe50 TH |
1007 | |
1008 | bdi->id = ++bdi_id_cursor; | |
1009 | ||
1010 | p = bdi_lookup_rb_node(bdi->id, &parent); | |
1011 | rb_link_node(&bdi->rb_node, parent, p); | |
1012 | rb_insert_color(&bdi->rb_node, &bdi_tree); | |
1013 | ||
46100071 | 1014 | list_add_tail_rcu(&bdi->bdi_list, &bdi_list); |
34f8fe50 | 1015 | |
46100071 TH |
1016 | spin_unlock_bh(&bdi_lock); |
1017 | ||
1018 | trace_writeback_bdi_register(bdi); | |
1019 | return 0; | |
b2e8fb6e | 1020 | } |
baf7a616 | 1021 | |
7c4cc300 | 1022 | int bdi_register(struct backing_dev_info *bdi, const char *fmt, ...) |
baf7a616 JK |
1023 | { |
1024 | va_list args; | |
1025 | int ret; | |
1026 | ||
1027 | va_start(args, fmt); | |
7c4cc300 | 1028 | ret = bdi_register_va(bdi, fmt, args); |
baf7a616 JK |
1029 | va_end(args); |
1030 | return ret; | |
1031 | } | |
46100071 | 1032 | EXPORT_SYMBOL(bdi_register); |
b2e8fb6e | 1033 | |
3c5d202b | 1034 | void bdi_set_owner(struct backing_dev_info *bdi, struct device *owner) |
df08c32c | 1035 | { |
3c5d202b | 1036 | WARN_ON_ONCE(bdi->owner); |
df08c32c DW |
1037 | bdi->owner = owner; |
1038 | get_device(owner); | |
df08c32c | 1039 | } |
df08c32c | 1040 | |
46100071 TH |
1041 | /* |
1042 | * Remove bdi from bdi_list, and ensure that it is no longer visible | |
1043 | */ | |
1044 | static void bdi_remove_from_list(struct backing_dev_info *bdi) | |
1045 | { | |
1046 | spin_lock_bh(&bdi_lock); | |
34f8fe50 | 1047 | rb_erase(&bdi->rb_node, &bdi_tree); |
46100071 TH |
1048 | list_del_rcu(&bdi->bdi_list); |
1049 | spin_unlock_bh(&bdi_lock); | |
b2e8fb6e | 1050 | |
46100071 TH |
1051 | synchronize_rcu_expedited(); |
1052 | } | |
cf0ca9fe | 1053 | |
b02176f3 | 1054 | void bdi_unregister(struct backing_dev_info *bdi) |
b2e8fb6e | 1055 | { |
5ed964f8 CH |
1056 | del_timer_sync(&bdi->laptop_mode_wb_timer); |
1057 | ||
f0054bb1 TH |
1058 | /* make sure nobody finds us on the bdi_list anymore */ |
1059 | bdi_remove_from_list(bdi); | |
1060 | wb_shutdown(&bdi->wb); | |
b1c51afc | 1061 | cgwb_bdi_unregister(bdi); |
7a401a97 | 1062 | |
3c376dfa ML |
1063 | /* |
1064 | * If this BDI's min ratio has been set, use bdi_set_min_ratio() to | |
1065 | * update the global bdi_min_ratio. | |
1066 | */ | |
1067 | if (bdi->min_ratio) | |
1068 | bdi_set_min_ratio(bdi, 0); | |
1069 | ||
c4db59d3 CH |
1070 | if (bdi->dev) { |
1071 | bdi_debug_unregister(bdi); | |
1072 | device_unregister(bdi->dev); | |
1073 | bdi->dev = NULL; | |
1074 | } | |
df08c32c DW |
1075 | |
1076 | if (bdi->owner) { | |
1077 | put_device(bdi->owner); | |
1078 | bdi->owner = NULL; | |
1079 | } | |
b02176f3 | 1080 | } |
c6fd3ac0 | 1081 | EXPORT_SYMBOL(bdi_unregister); |
c4db59d3 | 1082 | |
d03f6cdc JK |
1083 | static void release_bdi(struct kref *ref) |
1084 | { | |
1085 | struct backing_dev_info *bdi = | |
1086 | container_of(ref, struct backing_dev_info, refcnt); | |
1087 | ||
702f2d1e | 1088 | WARN_ON_ONCE(test_bit(WB_registered, &bdi->wb.state)); |
2e82b84c JK |
1089 | WARN_ON_ONCE(bdi->dev); |
1090 | wb_exit(&bdi->wb); | |
d03f6cdc JK |
1091 | kfree(bdi); |
1092 | } | |
1093 | ||
1094 | void bdi_put(struct backing_dev_info *bdi) | |
1095 | { | |
1096 | kref_put(&bdi->refcnt, release_bdi); | |
1097 | } | |
62bf42ad | 1098 | EXPORT_SYMBOL(bdi_put); |
d03f6cdc | 1099 | |
ccdf7741 CH |
1100 | struct backing_dev_info *inode_to_bdi(struct inode *inode) |
1101 | { | |
1102 | struct super_block *sb; | |
1103 | ||
1104 | if (!inode) | |
1105 | return &noop_backing_dev_info; | |
1106 | ||
1107 | sb = inode->i_sb; | |
1108 | #ifdef CONFIG_BLOCK | |
1109 | if (sb_is_blkdev_sb(sb)) | |
1110 | return I_BDEV(inode)->bd_disk->bdi; | |
1111 | #endif | |
1112 | return sb->s_bdi; | |
1113 | } | |
1114 | EXPORT_SYMBOL(inode_to_bdi); | |
1115 | ||
eb7ae5e0 CH |
1116 | const char *bdi_dev_name(struct backing_dev_info *bdi) |
1117 | { | |
1118 | if (!bdi || !bdi->dev) | |
1119 | return bdi_unknown_name; | |
6bd87eec | 1120 | return bdi->dev_name; |
eb7ae5e0 CH |
1121 | } |
1122 | EXPORT_SYMBOL_GPL(bdi_dev_name); |