Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 1 | |
| 2 | #include <linux/wait.h> |
| 3 | #include <linux/backing-dev.h> |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 4 | #include <linux/kthread.h> |
| 5 | #include <linux/freezer.h> |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 6 | #include <linux/fs.h> |
Jens Axboe | 2616015 | 2009-03-17 09:35:06 +0100 | [diff] [blame] | 7 | #include <linux/pagemap.h> |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 8 | #include <linux/mm.h> |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 9 | #include <linux/sched.h> |
| 10 | #include <linux/module.h> |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 11 | #include <linux/writeback.h> |
| 12 | #include <linux/device.h> |
| 13 | |
Jens Axboe | c3c5320 | 2010-04-22 11:37:01 +0200 | [diff] [blame^] | 14 | static atomic_long_t bdi_seq = ATOMIC_LONG_INIT(0); |
| 15 | |
Jens Axboe | 2616015 | 2009-03-17 09:35:06 +0100 | [diff] [blame] | 16 | void default_unplug_io_fn(struct backing_dev_info *bdi, struct page *page) |
| 17 | { |
| 18 | } |
| 19 | EXPORT_SYMBOL(default_unplug_io_fn); |
| 20 | |
| 21 | struct backing_dev_info default_backing_dev_info = { |
Jens Axboe | d993831 | 2009-06-12 14:45:52 +0200 | [diff] [blame] | 22 | .name = "default", |
Jens Axboe | 2616015 | 2009-03-17 09:35:06 +0100 | [diff] [blame] | 23 | .ra_pages = VM_MAX_READAHEAD * 1024 / PAGE_CACHE_SIZE, |
| 24 | .state = 0, |
| 25 | .capabilities = BDI_CAP_MAP_COPY, |
| 26 | .unplug_io_fn = default_unplug_io_fn, |
| 27 | }; |
| 28 | EXPORT_SYMBOL_GPL(default_backing_dev_info); |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 29 | |
| 30 | static struct class *bdi_class; |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 31 | |
| 32 | /* |
| 33 | * bdi_lock protects updates to bdi_list and bdi_pending_list, as well as |
| 34 | * reader side protection for bdi_pending_list. bdi_list has RCU reader side |
| 35 | * locking. |
| 36 | */ |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 37 | DEFINE_SPINLOCK(bdi_lock); |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 38 | LIST_HEAD(bdi_list); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 39 | LIST_HEAD(bdi_pending_list); |
| 40 | |
| 41 | static struct task_struct *sync_supers_tsk; |
| 42 | static struct timer_list sync_supers_timer; |
| 43 | |
| 44 | static int bdi_sync_supers(void *); |
| 45 | static void sync_supers_timer_fn(unsigned long); |
| 46 | static void arm_supers_timer(void); |
| 47 | |
| 48 | static void bdi_add_default_flusher_task(struct backing_dev_info *bdi); |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 49 | |
Miklos Szeredi | 76f1418 | 2008-04-30 00:54:36 -0700 | [diff] [blame] | 50 | #ifdef CONFIG_DEBUG_FS |
| 51 | #include <linux/debugfs.h> |
| 52 | #include <linux/seq_file.h> |
| 53 | |
| 54 | static struct dentry *bdi_debug_root; |
| 55 | |
| 56 | static void bdi_debug_init(void) |
| 57 | { |
| 58 | bdi_debug_root = debugfs_create_dir("bdi", NULL); |
| 59 | } |
| 60 | |
| 61 | static int bdi_debug_stats_show(struct seq_file *m, void *v) |
| 62 | { |
| 63 | struct backing_dev_info *bdi = m->private; |
Jens Axboe | f09b00d | 2009-05-25 09:08:21 +0200 | [diff] [blame] | 64 | struct bdi_writeback *wb; |
David Rientjes | 364aeb2 | 2009-01-06 14:39:29 -0800 | [diff] [blame] | 65 | unsigned long background_thresh; |
| 66 | unsigned long dirty_thresh; |
| 67 | unsigned long bdi_thresh; |
Jens Axboe | f09b00d | 2009-05-25 09:08:21 +0200 | [diff] [blame] | 68 | unsigned long nr_dirty, nr_io, nr_more_io, nr_wb; |
| 69 | struct inode *inode; |
| 70 | |
| 71 | /* |
| 72 | * inode lock is enough here, the bdi->wb_list is protected by |
| 73 | * RCU on the reader side |
| 74 | */ |
| 75 | nr_wb = nr_dirty = nr_io = nr_more_io = 0; |
| 76 | spin_lock(&inode_lock); |
| 77 | list_for_each_entry(wb, &bdi->wb_list, list) { |
| 78 | nr_wb++; |
| 79 | list_for_each_entry(inode, &wb->b_dirty, i_list) |
| 80 | nr_dirty++; |
| 81 | list_for_each_entry(inode, &wb->b_io, i_list) |
| 82 | nr_io++; |
| 83 | list_for_each_entry(inode, &wb->b_more_io, i_list) |
| 84 | nr_more_io++; |
| 85 | } |
| 86 | spin_unlock(&inode_lock); |
Miklos Szeredi | 76f1418 | 2008-04-30 00:54:36 -0700 | [diff] [blame] | 87 | |
| 88 | get_dirty_limits(&background_thresh, &dirty_thresh, &bdi_thresh, bdi); |
| 89 | |
| 90 | #define K(x) ((x) << (PAGE_SHIFT - 10)) |
| 91 | seq_printf(m, |
| 92 | "BdiWriteback: %8lu kB\n" |
| 93 | "BdiReclaimable: %8lu kB\n" |
| 94 | "BdiDirtyThresh: %8lu kB\n" |
| 95 | "DirtyThresh: %8lu kB\n" |
Jens Axboe | f09b00d | 2009-05-25 09:08:21 +0200 | [diff] [blame] | 96 | "BackgroundThresh: %8lu kB\n" |
Wu Fengguang | 961515f | 2009-10-09 13:01:27 +0200 | [diff] [blame] | 97 | "WritebackThreads: %8lu\n" |
Jens Axboe | f09b00d | 2009-05-25 09:08:21 +0200 | [diff] [blame] | 98 | "b_dirty: %8lu\n" |
| 99 | "b_io: %8lu\n" |
| 100 | "b_more_io: %8lu\n" |
| 101 | "bdi_list: %8u\n" |
| 102 | "state: %8lx\n" |
| 103 | "wb_mask: %8lx\n" |
| 104 | "wb_list: %8u\n" |
| 105 | "wb_cnt: %8u\n", |
Miklos Szeredi | 76f1418 | 2008-04-30 00:54:36 -0700 | [diff] [blame] | 106 | (unsigned long) K(bdi_stat(bdi, BDI_WRITEBACK)), |
| 107 | (unsigned long) K(bdi_stat(bdi, BDI_RECLAIMABLE)), |
Jens Axboe | f09b00d | 2009-05-25 09:08:21 +0200 | [diff] [blame] | 108 | K(bdi_thresh), K(dirty_thresh), |
| 109 | K(background_thresh), nr_wb, nr_dirty, nr_io, nr_more_io, |
| 110 | !list_empty(&bdi->bdi_list), bdi->state, bdi->wb_mask, |
| 111 | !list_empty(&bdi->wb_list), bdi->wb_cnt); |
Miklos Szeredi | 76f1418 | 2008-04-30 00:54:36 -0700 | [diff] [blame] | 112 | #undef K |
| 113 | |
| 114 | return 0; |
| 115 | } |
| 116 | |
| 117 | static int bdi_debug_stats_open(struct inode *inode, struct file *file) |
| 118 | { |
| 119 | return single_open(file, bdi_debug_stats_show, inode->i_private); |
| 120 | } |
| 121 | |
| 122 | static const struct file_operations bdi_debug_stats_fops = { |
| 123 | .open = bdi_debug_stats_open, |
| 124 | .read = seq_read, |
| 125 | .llseek = seq_lseek, |
| 126 | .release = single_release, |
| 127 | }; |
| 128 | |
| 129 | static void bdi_debug_register(struct backing_dev_info *bdi, const char *name) |
| 130 | { |
| 131 | bdi->debug_dir = debugfs_create_dir(name, bdi_debug_root); |
| 132 | bdi->debug_stats = debugfs_create_file("stats", 0444, bdi->debug_dir, |
| 133 | bdi, &bdi_debug_stats_fops); |
| 134 | } |
| 135 | |
| 136 | static void bdi_debug_unregister(struct backing_dev_info *bdi) |
| 137 | { |
| 138 | debugfs_remove(bdi->debug_stats); |
| 139 | debugfs_remove(bdi->debug_dir); |
| 140 | } |
| 141 | #else |
| 142 | static inline void bdi_debug_init(void) |
| 143 | { |
| 144 | } |
| 145 | static inline void bdi_debug_register(struct backing_dev_info *bdi, |
| 146 | const char *name) |
| 147 | { |
| 148 | } |
| 149 | static inline void bdi_debug_unregister(struct backing_dev_info *bdi) |
| 150 | { |
| 151 | } |
| 152 | #endif |
| 153 | |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 154 | static ssize_t read_ahead_kb_store(struct device *dev, |
| 155 | struct device_attribute *attr, |
| 156 | const char *buf, size_t count) |
| 157 | { |
| 158 | struct backing_dev_info *bdi = dev_get_drvdata(dev); |
| 159 | char *end; |
| 160 | unsigned long read_ahead_kb; |
| 161 | ssize_t ret = -EINVAL; |
| 162 | |
| 163 | read_ahead_kb = simple_strtoul(buf, &end, 10); |
| 164 | if (*buf && (end[0] == '\0' || (end[0] == '\n' && end[1] == '\0'))) { |
| 165 | bdi->ra_pages = read_ahead_kb >> (PAGE_SHIFT - 10); |
| 166 | ret = count; |
| 167 | } |
| 168 | return ret; |
| 169 | } |
| 170 | |
| 171 | #define K(pages) ((pages) << (PAGE_SHIFT - 10)) |
| 172 | |
| 173 | #define BDI_SHOW(name, expr) \ |
| 174 | static ssize_t name##_show(struct device *dev, \ |
| 175 | struct device_attribute *attr, char *page) \ |
| 176 | { \ |
| 177 | struct backing_dev_info *bdi = dev_get_drvdata(dev); \ |
| 178 | \ |
| 179 | return snprintf(page, PAGE_SIZE-1, "%lld\n", (long long)expr); \ |
| 180 | } |
| 181 | |
| 182 | BDI_SHOW(read_ahead_kb, K(bdi->ra_pages)) |
| 183 | |
Peter Zijlstra | 189d3c4 | 2008-04-30 00:54:35 -0700 | [diff] [blame] | 184 | static ssize_t min_ratio_store(struct device *dev, |
| 185 | struct device_attribute *attr, const char *buf, size_t count) |
| 186 | { |
| 187 | struct backing_dev_info *bdi = dev_get_drvdata(dev); |
| 188 | char *end; |
| 189 | unsigned int ratio; |
| 190 | ssize_t ret = -EINVAL; |
| 191 | |
| 192 | ratio = simple_strtoul(buf, &end, 10); |
| 193 | if (*buf && (end[0] == '\0' || (end[0] == '\n' && end[1] == '\0'))) { |
| 194 | ret = bdi_set_min_ratio(bdi, ratio); |
| 195 | if (!ret) |
| 196 | ret = count; |
| 197 | } |
| 198 | return ret; |
| 199 | } |
| 200 | BDI_SHOW(min_ratio, bdi->min_ratio) |
| 201 | |
Peter Zijlstra | a42dde0 | 2008-04-30 00:54:36 -0700 | [diff] [blame] | 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); |
| 206 | char *end; |
| 207 | unsigned int ratio; |
| 208 | ssize_t ret = -EINVAL; |
| 209 | |
| 210 | ratio = simple_strtoul(buf, &end, 10); |
| 211 | if (*buf && (end[0] == '\0' || (end[0] == '\n' && end[1] == '\0'))) { |
| 212 | ret = bdi_set_max_ratio(bdi, ratio); |
| 213 | if (!ret) |
| 214 | ret = count; |
| 215 | } |
| 216 | return ret; |
| 217 | } |
| 218 | BDI_SHOW(max_ratio, bdi->max_ratio) |
| 219 | |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 220 | #define __ATTR_RW(attr) __ATTR(attr, 0644, attr##_show, attr##_store) |
| 221 | |
| 222 | static struct device_attribute bdi_dev_attrs[] = { |
| 223 | __ATTR_RW(read_ahead_kb), |
Peter Zijlstra | 189d3c4 | 2008-04-30 00:54:35 -0700 | [diff] [blame] | 224 | __ATTR_RW(min_ratio), |
Peter Zijlstra | a42dde0 | 2008-04-30 00:54:36 -0700 | [diff] [blame] | 225 | __ATTR_RW(max_ratio), |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 226 | __ATTR_NULL, |
| 227 | }; |
| 228 | |
| 229 | static __init int bdi_class_init(void) |
| 230 | { |
| 231 | bdi_class = class_create(THIS_MODULE, "bdi"); |
Anton Blanchard | 1442145 | 2010-04-02 09:46:55 +0200 | [diff] [blame] | 232 | if (IS_ERR(bdi_class)) |
| 233 | return PTR_ERR(bdi_class); |
| 234 | |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 235 | bdi_class->dev_attrs = bdi_dev_attrs; |
Miklos Szeredi | 76f1418 | 2008-04-30 00:54:36 -0700 | [diff] [blame] | 236 | bdi_debug_init(); |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 237 | return 0; |
| 238 | } |
Miklos Szeredi | 76f1418 | 2008-04-30 00:54:36 -0700 | [diff] [blame] | 239 | postcore_initcall(bdi_class_init); |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 240 | |
Jens Axboe | 2616015 | 2009-03-17 09:35:06 +0100 | [diff] [blame] | 241 | static int __init default_bdi_init(void) |
| 242 | { |
| 243 | int err; |
| 244 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 245 | sync_supers_tsk = kthread_run(bdi_sync_supers, NULL, "sync_supers"); |
| 246 | BUG_ON(IS_ERR(sync_supers_tsk)); |
| 247 | |
| 248 | init_timer(&sync_supers_timer); |
| 249 | setup_timer(&sync_supers_timer, sync_supers_timer_fn, 0); |
| 250 | arm_supers_timer(); |
| 251 | |
Jens Axboe | 2616015 | 2009-03-17 09:35:06 +0100 | [diff] [blame] | 252 | err = bdi_init(&default_backing_dev_info); |
| 253 | if (!err) |
| 254 | bdi_register(&default_backing_dev_info, NULL, "default"); |
| 255 | |
| 256 | return err; |
| 257 | } |
| 258 | subsys_initcall(default_bdi_init); |
| 259 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 260 | static void bdi_wb_init(struct bdi_writeback *wb, struct backing_dev_info *bdi) |
| 261 | { |
| 262 | memset(wb, 0, sizeof(*wb)); |
| 263 | |
| 264 | wb->bdi = bdi; |
| 265 | wb->last_old_flush = jiffies; |
| 266 | INIT_LIST_HEAD(&wb->b_dirty); |
| 267 | INIT_LIST_HEAD(&wb->b_io); |
| 268 | INIT_LIST_HEAD(&wb->b_more_io); |
| 269 | } |
| 270 | |
| 271 | static void bdi_task_init(struct backing_dev_info *bdi, |
| 272 | struct bdi_writeback *wb) |
| 273 | { |
| 274 | struct task_struct *tsk = current; |
| 275 | |
| 276 | spin_lock(&bdi->wb_lock); |
| 277 | list_add_tail_rcu(&wb->list, &bdi->wb_list); |
| 278 | spin_unlock(&bdi->wb_lock); |
| 279 | |
| 280 | tsk->flags |= PF_FLUSHER | PF_SWAPWRITE; |
| 281 | set_freezable(); |
| 282 | |
| 283 | /* |
| 284 | * Our parent may run at a different priority, just set us to normal |
| 285 | */ |
| 286 | set_user_nice(tsk, 0); |
| 287 | } |
| 288 | |
| 289 | static int bdi_start_fn(void *ptr) |
| 290 | { |
| 291 | struct bdi_writeback *wb = ptr; |
| 292 | struct backing_dev_info *bdi = wb->bdi; |
| 293 | int ret; |
| 294 | |
| 295 | /* |
| 296 | * Add us to the active bdi_list |
| 297 | */ |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 298 | spin_lock_bh(&bdi_lock); |
| 299 | list_add_rcu(&bdi->bdi_list, &bdi_list); |
| 300 | spin_unlock_bh(&bdi_lock); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 301 | |
| 302 | bdi_task_init(bdi, wb); |
| 303 | |
| 304 | /* |
| 305 | * Clear pending bit and wakeup anybody waiting to tear us down |
| 306 | */ |
| 307 | clear_bit(BDI_pending, &bdi->state); |
| 308 | smp_mb__after_clear_bit(); |
| 309 | wake_up_bit(&bdi->state, BDI_pending); |
| 310 | |
| 311 | ret = bdi_writeback_task(wb); |
| 312 | |
| 313 | /* |
| 314 | * Remove us from the list |
| 315 | */ |
| 316 | spin_lock(&bdi->wb_lock); |
| 317 | list_del_rcu(&wb->list); |
| 318 | spin_unlock(&bdi->wb_lock); |
| 319 | |
| 320 | /* |
| 321 | * Flush any work that raced with us exiting. No new work |
| 322 | * will be added, since this bdi isn't discoverable anymore. |
| 323 | */ |
| 324 | if (!list_empty(&bdi->work_list)) |
| 325 | wb_do_writeback(wb, 1); |
| 326 | |
| 327 | wb->task = NULL; |
| 328 | return ret; |
| 329 | } |
| 330 | |
| 331 | int bdi_has_dirty_io(struct backing_dev_info *bdi) |
| 332 | { |
| 333 | return wb_has_dirty_io(&bdi->wb); |
| 334 | } |
| 335 | |
| 336 | static void bdi_flush_io(struct backing_dev_info *bdi) |
| 337 | { |
| 338 | struct writeback_control wbc = { |
| 339 | .bdi = bdi, |
| 340 | .sync_mode = WB_SYNC_NONE, |
| 341 | .older_than_this = NULL, |
| 342 | .range_cyclic = 1, |
| 343 | .nr_to_write = 1024, |
| 344 | }; |
| 345 | |
| 346 | writeback_inodes_wbc(&wbc); |
| 347 | } |
| 348 | |
| 349 | /* |
| 350 | * kupdated() used to do this. We cannot do it from the bdi_forker_task() |
| 351 | * or we risk deadlocking on ->s_umount. The longer term solution would be |
| 352 | * to implement sync_supers_bdi() or similar and simply do it from the |
| 353 | * bdi writeback tasks individually. |
| 354 | */ |
| 355 | static int bdi_sync_supers(void *unused) |
| 356 | { |
| 357 | set_user_nice(current, 0); |
| 358 | |
| 359 | while (!kthread_should_stop()) { |
| 360 | set_current_state(TASK_INTERRUPTIBLE); |
| 361 | schedule(); |
| 362 | |
| 363 | /* |
| 364 | * Do this periodically, like kupdated() did before. |
| 365 | */ |
| 366 | sync_supers(); |
| 367 | } |
| 368 | |
| 369 | return 0; |
| 370 | } |
| 371 | |
| 372 | static void arm_supers_timer(void) |
| 373 | { |
| 374 | unsigned long next; |
| 375 | |
| 376 | next = msecs_to_jiffies(dirty_writeback_interval * 10) + jiffies; |
| 377 | mod_timer(&sync_supers_timer, round_jiffies_up(next)); |
| 378 | } |
| 379 | |
| 380 | static void sync_supers_timer_fn(unsigned long unused) |
| 381 | { |
| 382 | wake_up_process(sync_supers_tsk); |
| 383 | arm_supers_timer(); |
| 384 | } |
| 385 | |
| 386 | static int bdi_forker_task(void *ptr) |
| 387 | { |
| 388 | struct bdi_writeback *me = ptr; |
| 389 | |
| 390 | bdi_task_init(me->bdi, me); |
| 391 | |
| 392 | for (;;) { |
| 393 | struct backing_dev_info *bdi, *tmp; |
| 394 | struct bdi_writeback *wb; |
| 395 | |
| 396 | /* |
| 397 | * Temporary measure, we want to make sure we don't see |
| 398 | * dirty data on the default backing_dev_info |
| 399 | */ |
| 400 | if (wb_has_dirty_io(me) || !list_empty(&me->bdi->work_list)) |
| 401 | wb_do_writeback(me, 0); |
| 402 | |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 403 | spin_lock_bh(&bdi_lock); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 404 | |
| 405 | /* |
| 406 | * Check if any existing bdi's have dirty data without |
| 407 | * a thread registered. If so, set that up. |
| 408 | */ |
| 409 | list_for_each_entry_safe(bdi, tmp, &bdi_list, bdi_list) { |
| 410 | if (bdi->wb.task) |
| 411 | continue; |
| 412 | if (list_empty(&bdi->work_list) && |
| 413 | !bdi_has_dirty_io(bdi)) |
| 414 | continue; |
| 415 | |
| 416 | bdi_add_default_flusher_task(bdi); |
| 417 | } |
| 418 | |
| 419 | set_current_state(TASK_INTERRUPTIBLE); |
| 420 | |
| 421 | if (list_empty(&bdi_pending_list)) { |
| 422 | unsigned long wait; |
| 423 | |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 424 | spin_unlock_bh(&bdi_lock); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 425 | wait = msecs_to_jiffies(dirty_writeback_interval * 10); |
| 426 | schedule_timeout(wait); |
| 427 | try_to_freeze(); |
| 428 | continue; |
| 429 | } |
| 430 | |
| 431 | __set_current_state(TASK_RUNNING); |
| 432 | |
| 433 | /* |
| 434 | * This is our real job - check for pending entries in |
| 435 | * bdi_pending_list, and create the tasks that got added |
| 436 | */ |
| 437 | bdi = list_entry(bdi_pending_list.next, struct backing_dev_info, |
| 438 | bdi_list); |
| 439 | list_del_init(&bdi->bdi_list); |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 440 | spin_unlock_bh(&bdi_lock); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 441 | |
| 442 | wb = &bdi->wb; |
| 443 | wb->task = kthread_run(bdi_start_fn, wb, "flush-%s", |
| 444 | dev_name(bdi->dev)); |
| 445 | /* |
| 446 | * If task creation fails, then readd the bdi to |
| 447 | * the pending list and force writeout of the bdi |
| 448 | * from this forker thread. That will free some memory |
| 449 | * and we can try again. |
| 450 | */ |
| 451 | if (IS_ERR(wb->task)) { |
| 452 | wb->task = NULL; |
| 453 | |
| 454 | /* |
| 455 | * Add this 'bdi' to the back, so we get |
| 456 | * a chance to flush other bdi's to free |
| 457 | * memory. |
| 458 | */ |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 459 | spin_lock_bh(&bdi_lock); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 460 | list_add_tail(&bdi->bdi_list, &bdi_pending_list); |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 461 | spin_unlock_bh(&bdi_lock); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 462 | |
| 463 | bdi_flush_io(bdi); |
| 464 | } |
| 465 | } |
| 466 | |
| 467 | return 0; |
| 468 | } |
| 469 | |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 470 | static void bdi_add_to_pending(struct rcu_head *head) |
| 471 | { |
| 472 | struct backing_dev_info *bdi; |
| 473 | |
| 474 | bdi = container_of(head, struct backing_dev_info, rcu_head); |
| 475 | INIT_LIST_HEAD(&bdi->bdi_list); |
| 476 | |
| 477 | spin_lock(&bdi_lock); |
| 478 | list_add_tail(&bdi->bdi_list, &bdi_pending_list); |
| 479 | spin_unlock(&bdi_lock); |
| 480 | |
| 481 | /* |
| 482 | * We are now on the pending list, wake up bdi_forker_task() |
| 483 | * to finish the job and add us back to the active bdi_list |
| 484 | */ |
| 485 | wake_up_process(default_backing_dev_info.wb.task); |
| 486 | } |
| 487 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 488 | /* |
| 489 | * Add the default flusher task that gets created for any bdi |
| 490 | * that has dirty data pending writeout |
| 491 | */ |
| 492 | void static bdi_add_default_flusher_task(struct backing_dev_info *bdi) |
| 493 | { |
| 494 | if (!bdi_cap_writeback_dirty(bdi)) |
| 495 | return; |
| 496 | |
Jens Axboe | 500b067 | 2009-09-09 09:10:25 +0200 | [diff] [blame] | 497 | if (WARN_ON(!test_bit(BDI_registered, &bdi->state))) { |
| 498 | printk(KERN_ERR "bdi %p/%s is not registered!\n", |
| 499 | bdi, bdi->name); |
| 500 | return; |
| 501 | } |
| 502 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 503 | /* |
| 504 | * Check with the helper whether to proceed adding a task. Will only |
| 505 | * abort if we two or more simultanous calls to |
| 506 | * bdi_add_default_flusher_task() occured, further additions will block |
| 507 | * waiting for previous additions to finish. |
| 508 | */ |
| 509 | if (!test_and_set_bit(BDI_pending, &bdi->state)) { |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 510 | list_del_rcu(&bdi->bdi_list); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 511 | |
| 512 | /* |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 513 | * We must wait for the current RCU period to end before |
| 514 | * moving to the pending list. So schedule that operation |
| 515 | * from an RCU callback. |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 516 | */ |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 517 | call_rcu(&bdi->rcu_head, bdi_add_to_pending); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 518 | } |
| 519 | } |
| 520 | |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 521 | /* |
| 522 | * Remove bdi from bdi_list, and ensure that it is no longer visible |
| 523 | */ |
| 524 | static void bdi_remove_from_list(struct backing_dev_info *bdi) |
| 525 | { |
| 526 | spin_lock_bh(&bdi_lock); |
| 527 | list_del_rcu(&bdi->bdi_list); |
| 528 | spin_unlock_bh(&bdi_lock); |
| 529 | |
| 530 | synchronize_rcu(); |
| 531 | } |
| 532 | |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 533 | int bdi_register(struct backing_dev_info *bdi, struct device *parent, |
| 534 | const char *fmt, ...) |
| 535 | { |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 536 | va_list args; |
| 537 | int ret = 0; |
| 538 | struct device *dev; |
| 539 | |
Andrew Morton | 69fc208 | 2008-12-09 13:14:06 -0800 | [diff] [blame] | 540 | if (bdi->dev) /* The driver needs to use separate queues per device */ |
Kay Sievers | f1d0b06 | 2008-12-02 10:31:50 -0800 | [diff] [blame] | 541 | goto exit; |
| 542 | |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 543 | va_start(args, fmt); |
Greg Kroah-Hartman | 19051c5 | 2008-05-15 13:44:08 -0700 | [diff] [blame] | 544 | dev = device_create_vargs(bdi_class, parent, MKDEV(0, 0), bdi, fmt, args); |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 545 | va_end(args); |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 546 | if (IS_ERR(dev)) { |
| 547 | ret = PTR_ERR(dev); |
| 548 | goto exit; |
| 549 | } |
| 550 | |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 551 | spin_lock_bh(&bdi_lock); |
| 552 | list_add_tail_rcu(&bdi->bdi_list, &bdi_list); |
| 553 | spin_unlock_bh(&bdi_lock); |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 554 | |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 555 | bdi->dev = dev; |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 556 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 557 | /* |
| 558 | * Just start the forker thread for our default backing_dev_info, |
| 559 | * and add other bdi's to the list. They will get a thread created |
| 560 | * on-demand when they need it. |
| 561 | */ |
| 562 | if (bdi_cap_flush_forker(bdi)) { |
| 563 | struct bdi_writeback *wb = &bdi->wb; |
| 564 | |
| 565 | wb->task = kthread_run(bdi_forker_task, wb, "bdi-%s", |
| 566 | dev_name(dev)); |
| 567 | if (IS_ERR(wb->task)) { |
| 568 | wb->task = NULL; |
| 569 | ret = -ENOMEM; |
| 570 | |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 571 | bdi_remove_from_list(bdi); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 572 | goto exit; |
| 573 | } |
| 574 | } |
| 575 | |
| 576 | bdi_debug_register(bdi, dev_name(dev)); |
Jens Axboe | 500b067 | 2009-09-09 09:10:25 +0200 | [diff] [blame] | 577 | set_bit(BDI_registered, &bdi->state); |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 578 | exit: |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 579 | return ret; |
| 580 | } |
| 581 | EXPORT_SYMBOL(bdi_register); |
| 582 | |
| 583 | int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev) |
| 584 | { |
| 585 | return bdi_register(bdi, NULL, "%u:%u", MAJOR(dev), MINOR(dev)); |
| 586 | } |
| 587 | EXPORT_SYMBOL(bdi_register_dev); |
| 588 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 589 | /* |
| 590 | * Remove bdi from the global list and shutdown any threads we have running |
| 591 | */ |
| 592 | static void bdi_wb_shutdown(struct backing_dev_info *bdi) |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 593 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 594 | struct bdi_writeback *wb; |
| 595 | |
| 596 | if (!bdi_cap_writeback_dirty(bdi)) |
| 597 | return; |
| 598 | |
| 599 | /* |
| 600 | * If setup is pending, wait for that to complete first |
| 601 | */ |
| 602 | wait_on_bit(&bdi->state, BDI_pending, bdi_sched_wait, |
| 603 | TASK_UNINTERRUPTIBLE); |
| 604 | |
| 605 | /* |
| 606 | * Make sure nobody finds us on the bdi_list anymore |
| 607 | */ |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 608 | bdi_remove_from_list(bdi); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 609 | |
| 610 | /* |
| 611 | * Finally, kill the kernel threads. We don't need to be RCU |
Romit Dasgupta | c62b17a | 2009-11-12 13:08:11 +0100 | [diff] [blame] | 612 | * safe anymore, since the bdi is gone from visibility. Force |
| 613 | * unfreeze of the thread before calling kthread_stop(), otherwise |
| 614 | * it would never exet if it is currently stuck in the refrigerator. |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 615 | */ |
Romit Dasgupta | c62b17a | 2009-11-12 13:08:11 +0100 | [diff] [blame] | 616 | list_for_each_entry(wb, &bdi->wb_list, list) { |
OGAWA Hirofumi | bf7ec5b | 2009-12-03 13:49:43 +0100 | [diff] [blame] | 617 | thaw_process(wb->task); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 618 | kthread_stop(wb->task); |
Romit Dasgupta | c62b17a | 2009-11-12 13:08:11 +0100 | [diff] [blame] | 619 | } |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 620 | } |
| 621 | |
Jens Axboe | 592b09a | 2009-10-29 11:46:12 +0100 | [diff] [blame] | 622 | /* |
| 623 | * This bdi is going away now, make sure that no super_blocks point to it |
| 624 | */ |
| 625 | static void bdi_prune_sb(struct backing_dev_info *bdi) |
| 626 | { |
| 627 | struct super_block *sb; |
| 628 | |
| 629 | spin_lock(&sb_lock); |
| 630 | list_for_each_entry(sb, &super_blocks, s_list) { |
| 631 | if (sb->s_bdi == bdi) |
| 632 | sb->s_bdi = NULL; |
| 633 | } |
| 634 | spin_unlock(&sb_lock); |
| 635 | } |
| 636 | |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 637 | void bdi_unregister(struct backing_dev_info *bdi) |
| 638 | { |
| 639 | if (bdi->dev) { |
Jens Axboe | 8c4db33 | 2009-11-03 20:18:44 +0100 | [diff] [blame] | 640 | bdi_prune_sb(bdi); |
| 641 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 642 | if (!bdi_cap_flush_forker(bdi)) |
| 643 | bdi_wb_shutdown(bdi); |
Miklos Szeredi | 76f1418 | 2008-04-30 00:54:36 -0700 | [diff] [blame] | 644 | bdi_debug_unregister(bdi); |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 645 | device_unregister(bdi->dev); |
| 646 | bdi->dev = NULL; |
| 647 | } |
| 648 | } |
| 649 | EXPORT_SYMBOL(bdi_unregister); |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 650 | |
Peter Zijlstra | b2e8fb6 | 2007-10-16 23:25:47 -0700 | [diff] [blame] | 651 | int bdi_init(struct backing_dev_info *bdi) |
| 652 | { |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 653 | int i, err; |
Peter Zijlstra | b2e8fb6 | 2007-10-16 23:25:47 -0700 | [diff] [blame] | 654 | |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 655 | bdi->dev = NULL; |
| 656 | |
Peter Zijlstra | 189d3c4 | 2008-04-30 00:54:35 -0700 | [diff] [blame] | 657 | bdi->min_ratio = 0; |
Peter Zijlstra | a42dde0 | 2008-04-30 00:54:36 -0700 | [diff] [blame] | 658 | bdi->max_ratio = 100; |
| 659 | bdi->max_prop_frac = PROP_FRAC_BASE; |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 660 | spin_lock_init(&bdi->wb_lock); |
Jens Axboe | cfc4ba5 | 2009-09-14 13:12:40 +0200 | [diff] [blame] | 661 | INIT_RCU_HEAD(&bdi->rcu_head); |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 662 | INIT_LIST_HEAD(&bdi->bdi_list); |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 663 | INIT_LIST_HEAD(&bdi->wb_list); |
| 664 | INIT_LIST_HEAD(&bdi->work_list); |
| 665 | |
| 666 | bdi_wb_init(&bdi->wb, bdi); |
| 667 | |
| 668 | /* |
| 669 | * Just one thread support for now, hard code mask and count |
| 670 | */ |
| 671 | bdi->wb_mask = 1; |
| 672 | bdi->wb_cnt = 1; |
Peter Zijlstra | 189d3c4 | 2008-04-30 00:54:35 -0700 | [diff] [blame] | 673 | |
Peter Zijlstra | b2e8fb6 | 2007-10-16 23:25:47 -0700 | [diff] [blame] | 674 | for (i = 0; i < NR_BDI_STAT_ITEMS; i++) { |
Peter Zijlstra | ea31951 | 2008-12-26 15:08:55 +0100 | [diff] [blame] | 675 | err = percpu_counter_init(&bdi->bdi_stat[i], 0); |
Peter Zijlstra | 04fbfdc | 2007-10-16 23:25:50 -0700 | [diff] [blame] | 676 | if (err) |
| 677 | goto err; |
| 678 | } |
| 679 | |
| 680 | bdi->dirty_exceeded = 0; |
| 681 | err = prop_local_init_percpu(&bdi->completions); |
| 682 | |
| 683 | if (err) { |
| 684 | err: |
Denis Cheng | 4b01a0b | 2007-12-04 23:45:07 -0800 | [diff] [blame] | 685 | while (i--) |
Peter Zijlstra | 04fbfdc | 2007-10-16 23:25:50 -0700 | [diff] [blame] | 686 | percpu_counter_destroy(&bdi->bdi_stat[i]); |
Peter Zijlstra | b2e8fb6 | 2007-10-16 23:25:47 -0700 | [diff] [blame] | 687 | } |
| 688 | |
| 689 | return err; |
| 690 | } |
| 691 | EXPORT_SYMBOL(bdi_init); |
| 692 | |
| 693 | void bdi_destroy(struct backing_dev_info *bdi) |
| 694 | { |
| 695 | int i; |
| 696 | |
Jens Axboe | ce5f8e7 | 2009-09-14 12:57:56 +0200 | [diff] [blame] | 697 | /* |
| 698 | * Splice our entries to the default_backing_dev_info, if this |
| 699 | * bdi disappears |
| 700 | */ |
| 701 | if (bdi_has_dirty_io(bdi)) { |
| 702 | struct bdi_writeback *dst = &default_backing_dev_info.wb; |
| 703 | |
| 704 | spin_lock(&inode_lock); |
| 705 | list_splice(&bdi->wb.b_dirty, &dst->b_dirty); |
| 706 | list_splice(&bdi->wb.b_io, &dst->b_io); |
| 707 | list_splice(&bdi->wb.b_more_io, &dst->b_more_io); |
| 708 | spin_unlock(&inode_lock); |
| 709 | } |
Jens Axboe | 66f3b8e | 2009-09-02 09:19:46 +0200 | [diff] [blame] | 710 | |
Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 711 | bdi_unregister(bdi); |
| 712 | |
Peter Zijlstra | b2e8fb6 | 2007-10-16 23:25:47 -0700 | [diff] [blame] | 713 | for (i = 0; i < NR_BDI_STAT_ITEMS; i++) |
| 714 | percpu_counter_destroy(&bdi->bdi_stat[i]); |
Peter Zijlstra | 04fbfdc | 2007-10-16 23:25:50 -0700 | [diff] [blame] | 715 | |
| 716 | prop_local_destroy_percpu(&bdi->completions); |
Peter Zijlstra | b2e8fb6 | 2007-10-16 23:25:47 -0700 | [diff] [blame] | 717 | } |
| 718 | EXPORT_SYMBOL(bdi_destroy); |
| 719 | |
Jens Axboe | c3c5320 | 2010-04-22 11:37:01 +0200 | [diff] [blame^] | 720 | /* |
| 721 | * For use from filesystems to quickly init and register a bdi associated |
| 722 | * with dirty writeback |
| 723 | */ |
| 724 | int bdi_setup_and_register(struct backing_dev_info *bdi, char *name, |
| 725 | unsigned int cap) |
| 726 | { |
| 727 | char tmp[32]; |
| 728 | int err; |
| 729 | |
| 730 | bdi->name = name; |
| 731 | bdi->capabilities = cap; |
| 732 | err = bdi_init(bdi); |
| 733 | if (err) |
| 734 | return err; |
| 735 | |
| 736 | sprintf(tmp, "%.28s%s", name, "-%d"); |
| 737 | err = bdi_register(bdi, NULL, tmp, atomic_long_inc_return(&bdi_seq)); |
| 738 | if (err) { |
| 739 | bdi_destroy(bdi); |
| 740 | return err; |
| 741 | } |
| 742 | |
| 743 | return 0; |
| 744 | } |
| 745 | EXPORT_SYMBOL(bdi_setup_and_register); |
| 746 | |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 747 | static wait_queue_head_t congestion_wqh[2] = { |
| 748 | __WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[0]), |
| 749 | __WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[1]) |
| 750 | }; |
| 751 | |
Jens Axboe | 1faa16d | 2009-04-06 14:48:01 +0200 | [diff] [blame] | 752 | void clear_bdi_congested(struct backing_dev_info *bdi, int sync) |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 753 | { |
| 754 | enum bdi_state bit; |
Jens Axboe | 1faa16d | 2009-04-06 14:48:01 +0200 | [diff] [blame] | 755 | wait_queue_head_t *wqh = &congestion_wqh[sync]; |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 756 | |
Jens Axboe | 1faa16d | 2009-04-06 14:48:01 +0200 | [diff] [blame] | 757 | bit = sync ? BDI_sync_congested : BDI_async_congested; |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 758 | clear_bit(bit, &bdi->state); |
| 759 | smp_mb__after_clear_bit(); |
| 760 | if (waitqueue_active(wqh)) |
| 761 | wake_up(wqh); |
| 762 | } |
| 763 | EXPORT_SYMBOL(clear_bdi_congested); |
| 764 | |
Jens Axboe | 1faa16d | 2009-04-06 14:48:01 +0200 | [diff] [blame] | 765 | void set_bdi_congested(struct backing_dev_info *bdi, int sync) |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 766 | { |
| 767 | enum bdi_state bit; |
| 768 | |
Jens Axboe | 1faa16d | 2009-04-06 14:48:01 +0200 | [diff] [blame] | 769 | bit = sync ? BDI_sync_congested : BDI_async_congested; |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 770 | set_bit(bit, &bdi->state); |
| 771 | } |
| 772 | EXPORT_SYMBOL(set_bdi_congested); |
| 773 | |
| 774 | /** |
| 775 | * congestion_wait - wait for a backing_dev to become uncongested |
Jens Axboe | 8aa7e84 | 2009-07-09 14:52:32 +0200 | [diff] [blame] | 776 | * @sync: SYNC or ASYNC IO |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 777 | * @timeout: timeout in jiffies |
| 778 | * |
| 779 | * Waits for up to @timeout jiffies for a backing_dev (any backing_dev) to exit |
| 780 | * write congestion. If no backing_devs are congested then just wait for the |
| 781 | * next write to be completed. |
| 782 | */ |
Jens Axboe | 8aa7e84 | 2009-07-09 14:52:32 +0200 | [diff] [blame] | 783 | long congestion_wait(int sync, long timeout) |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 784 | { |
| 785 | long ret; |
| 786 | DEFINE_WAIT(wait); |
Jens Axboe | 8aa7e84 | 2009-07-09 14:52:32 +0200 | [diff] [blame] | 787 | wait_queue_head_t *wqh = &congestion_wqh[sync]; |
Andrew Morton | 3fcfab1 | 2006-10-19 23:28:16 -0700 | [diff] [blame] | 788 | |
| 789 | prepare_to_wait(wqh, &wait, TASK_UNINTERRUPTIBLE); |
| 790 | ret = io_schedule_timeout(timeout); |
| 791 | finish_wait(wqh, &wait); |
| 792 | return ret; |
| 793 | } |
| 794 | EXPORT_SYMBOL(congestion_wait); |
Peter Zijlstra | 04fbfdc | 2007-10-16 23:25:50 -0700 | [diff] [blame] | 795 | |