Commit | Line | Data |
---|---|---|
2056a782 | 1 | /* |
0fe23479 | 2 | * Copyright (C) 2006 Jens Axboe <axboe@kernel.dk> |
2056a782 JA |
3 | * |
4 | * This program is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the GNU General Public License version 2 as | |
6 | * published by the Free Software Foundation. | |
7 | * | |
8 | * This program is distributed in the hope that it will be useful, | |
9 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
11 | * GNU General Public License for more details. | |
12 | * | |
13 | * You should have received a copy of the GNU General Public License | |
14 | * along with this program; if not, write to the Free Software | |
15 | * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA | |
16 | * | |
17 | */ | |
2056a782 JA |
18 | #include <linux/kernel.h> |
19 | #include <linux/blkdev.h> | |
20 | #include <linux/blktrace_api.h> | |
21 | #include <linux/percpu.h> | |
22 | #include <linux/init.h> | |
23 | #include <linux/mutex.h> | |
24 | #include <linux/debugfs.h> | |
be1c6341 | 25 | #include <linux/time.h> |
2056a782 JA |
26 | #include <asm/uaccess.h> |
27 | ||
2056a782 JA |
28 | static unsigned int blktrace_seq __read_mostly = 1; |
29 | ||
be1c6341 OK |
30 | /* |
31 | * Send out a notify message. | |
32 | */ | |
a863055b JA |
33 | static void trace_note(struct blk_trace *bt, pid_t pid, int action, |
34 | const void *data, size_t len) | |
be1c6341 OK |
35 | { |
36 | struct blk_io_trace *t; | |
be1c6341 OK |
37 | |
38 | t = relay_reserve(bt->rchan, sizeof(*t) + len); | |
d3d9d2a5 JA |
39 | if (t) { |
40 | const int cpu = smp_processor_id(); | |
41 | ||
42 | t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION; | |
2997c8c4 | 43 | t->time = ktime_to_ns(ktime_get()); |
d3d9d2a5 JA |
44 | t->device = bt->dev; |
45 | t->action = action; | |
46 | t->pid = pid; | |
47 | t->cpu = cpu; | |
48 | t->pdu_len = len; | |
49 | memcpy((void *) t + sizeof(*t), data, len); | |
50 | } | |
be1c6341 OK |
51 | } |
52 | ||
2056a782 JA |
53 | /* |
54 | * Send out a notify for this process, if we haven't done so since a trace | |
55 | * started | |
56 | */ | |
57 | static void trace_note_tsk(struct blk_trace *bt, struct task_struct *tsk) | |
58 | { | |
a863055b JA |
59 | tsk->btrace_seq = blktrace_seq; |
60 | trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm, sizeof(tsk->comm)); | |
be1c6341 | 61 | } |
2056a782 | 62 | |
be1c6341 OK |
63 | static void trace_note_time(struct blk_trace *bt) |
64 | { | |
65 | struct timespec now; | |
66 | unsigned long flags; | |
67 | u32 words[2]; | |
68 | ||
69 | getnstimeofday(&now); | |
70 | words[0] = now.tv_sec; | |
71 | words[1] = now.tv_nsec; | |
72 | ||
73 | local_irq_save(flags); | |
74 | trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words)); | |
75 | local_irq_restore(flags); | |
2056a782 JA |
76 | } |
77 | ||
9d5f09a4 AB |
78 | void __trace_note_message(struct blk_trace *bt, const char *fmt, ...) |
79 | { | |
80 | int n; | |
81 | va_list args; | |
82 | static char bt_msg_buf[BLK_TN_MAX_MSG]; | |
83 | ||
84 | va_start(args, fmt); | |
85 | n = vscnprintf(bt_msg_buf, BLK_TN_MAX_MSG, fmt, args); | |
86 | va_end(args); | |
87 | ||
88 | trace_note(bt, 0, BLK_TN_MESSAGE, bt_msg_buf, n); | |
89 | } | |
90 | EXPORT_SYMBOL_GPL(__trace_note_message); | |
91 | ||
2056a782 JA |
92 | static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector, |
93 | pid_t pid) | |
94 | { | |
95 | if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0) | |
96 | return 1; | |
97 | if (sector < bt->start_lba || sector > bt->end_lba) | |
98 | return 1; | |
99 | if (bt->pid && pid != bt->pid) | |
100 | return 1; | |
101 | ||
102 | return 0; | |
103 | } | |
104 | ||
105 | /* | |
106 | * Data direction bit lookup | |
107 | */ | |
108 | static u32 ddir_act[2] __read_mostly = { BLK_TC_ACT(BLK_TC_READ), BLK_TC_ACT(BLK_TC_WRITE) }; | |
109 | ||
110 | /* | |
111 | * Bio action bits of interest | |
112 | */ | |
7457e6e2 | 113 | static u32 bio_act[9] __read_mostly = { 0, BLK_TC_ACT(BLK_TC_BARRIER), BLK_TC_ACT(BLK_TC_SYNC), 0, BLK_TC_ACT(BLK_TC_AHEAD), 0, 0, 0, BLK_TC_ACT(BLK_TC_META) }; |
2056a782 JA |
114 | |
115 | /* | |
116 | * More could be added as needed, taking care to increment the decrementer | |
117 | * to get correct indexing | |
118 | */ | |
119 | #define trace_barrier_bit(rw) \ | |
120 | (((rw) & (1 << BIO_RW_BARRIER)) >> (BIO_RW_BARRIER - 0)) | |
121 | #define trace_sync_bit(rw) \ | |
122 | (((rw) & (1 << BIO_RW_SYNC)) >> (BIO_RW_SYNC - 1)) | |
40359ccb | 123 | #define trace_ahead_bit(rw) \ |
ad01b1ca | 124 | (((rw) & (1 << BIO_RW_AHEAD)) << (2 - BIO_RW_AHEAD)) |
7457e6e2 JA |
125 | #define trace_meta_bit(rw) \ |
126 | (((rw) & (1 << BIO_RW_META)) >> (BIO_RW_META - 3)) | |
2056a782 JA |
127 | |
128 | /* | |
129 | * The worker for the various blk_add_trace*() types. Fills out a | |
130 | * blk_io_trace structure and places it in a per-cpu subbuffer. | |
131 | */ | |
132 | void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes, | |
133 | int rw, u32 what, int error, int pdu_len, void *pdu_data) | |
134 | { | |
135 | struct task_struct *tsk = current; | |
136 | struct blk_io_trace *t; | |
137 | unsigned long flags; | |
138 | unsigned long *sequence; | |
139 | pid_t pid; | |
140 | int cpu; | |
141 | ||
142 | if (unlikely(bt->trace_state != Blktrace_running)) | |
143 | return; | |
144 | ||
145 | what |= ddir_act[rw & WRITE]; | |
146 | what |= bio_act[trace_barrier_bit(rw)]; | |
147 | what |= bio_act[trace_sync_bit(rw)]; | |
40359ccb | 148 | what |= bio_act[trace_ahead_bit(rw)]; |
7457e6e2 | 149 | what |= bio_act[trace_meta_bit(rw)]; |
2056a782 JA |
150 | |
151 | pid = tsk->pid; | |
152 | if (unlikely(act_log_check(bt, what, sector, pid))) | |
153 | return; | |
154 | ||
155 | /* | |
156 | * A word about the locking here - we disable interrupts to reserve | |
157 | * some space in the relay per-cpu buffer, to prevent an irq | |
158 | * from coming in and stepping on our toes. Once reserved, it's | |
159 | * enough to get preemption disabled to prevent read of this data | |
160 | * before we are through filling it. get_cpu()/put_cpu() does this | |
161 | * for us | |
162 | */ | |
163 | local_irq_save(flags); | |
164 | ||
165 | if (unlikely(tsk->btrace_seq != blktrace_seq)) | |
166 | trace_note_tsk(bt, tsk); | |
167 | ||
168 | t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len); | |
169 | if (t) { | |
170 | cpu = smp_processor_id(); | |
171 | sequence = per_cpu_ptr(bt->sequence, cpu); | |
172 | ||
173 | t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION; | |
174 | t->sequence = ++(*sequence); | |
2997c8c4 | 175 | t->time = ktime_to_ns(ktime_get()); |
2056a782 JA |
176 | t->sector = sector; |
177 | t->bytes = bytes; | |
178 | t->action = what; | |
179 | t->pid = pid; | |
180 | t->device = bt->dev; | |
181 | t->cpu = cpu; | |
182 | t->error = error; | |
183 | t->pdu_len = pdu_len; | |
184 | ||
185 | if (pdu_len) | |
186 | memcpy((void *) t + sizeof(*t), pdu_data, pdu_len); | |
187 | } | |
188 | ||
189 | local_irq_restore(flags); | |
190 | } | |
191 | ||
192 | EXPORT_SYMBOL_GPL(__blk_add_trace); | |
193 | ||
194 | static struct dentry *blk_tree_root; | |
11a57153 | 195 | static DEFINE_MUTEX(blk_tree_mutex); |
2056a782 JA |
196 | static unsigned int root_users; |
197 | ||
198 | static inline void blk_remove_root(void) | |
199 | { | |
200 | if (blk_tree_root) { | |
201 | debugfs_remove(blk_tree_root); | |
202 | blk_tree_root = NULL; | |
203 | } | |
204 | } | |
205 | ||
206 | static void blk_remove_tree(struct dentry *dir) | |
207 | { | |
208 | mutex_lock(&blk_tree_mutex); | |
209 | debugfs_remove(dir); | |
210 | if (--root_users == 0) | |
211 | blk_remove_root(); | |
212 | mutex_unlock(&blk_tree_mutex); | |
213 | } | |
214 | ||
215 | static struct dentry *blk_create_tree(const char *blk_name) | |
216 | { | |
217 | struct dentry *dir = NULL; | |
35fc51e7 | 218 | int created = 0; |
2056a782 JA |
219 | |
220 | mutex_lock(&blk_tree_mutex); | |
221 | ||
222 | if (!blk_tree_root) { | |
223 | blk_tree_root = debugfs_create_dir("block", NULL); | |
224 | if (!blk_tree_root) | |
225 | goto err; | |
35fc51e7 | 226 | created = 1; |
2056a782 JA |
227 | } |
228 | ||
229 | dir = debugfs_create_dir(blk_name, blk_tree_root); | |
230 | if (dir) | |
231 | root_users++; | |
35fc51e7 AK |
232 | else { |
233 | /* Delete root only if we created it */ | |
234 | if (created) | |
235 | blk_remove_root(); | |
236 | } | |
2056a782 JA |
237 | |
238 | err: | |
239 | mutex_unlock(&blk_tree_mutex); | |
240 | return dir; | |
241 | } | |
242 | ||
243 | static void blk_trace_cleanup(struct blk_trace *bt) | |
244 | { | |
245 | relay_close(bt->rchan); | |
246 | debugfs_remove(bt->dropped_file); | |
247 | blk_remove_tree(bt->dir); | |
248 | free_percpu(bt->sequence); | |
249 | kfree(bt); | |
250 | } | |
251 | ||
6da127ad | 252 | int blk_trace_remove(struct request_queue *q) |
2056a782 JA |
253 | { |
254 | struct blk_trace *bt; | |
255 | ||
256 | bt = xchg(&q->blk_trace, NULL); | |
257 | if (!bt) | |
258 | return -EINVAL; | |
259 | ||
260 | if (bt->trace_state == Blktrace_setup || | |
261 | bt->trace_state == Blktrace_stopped) | |
262 | blk_trace_cleanup(bt); | |
263 | ||
264 | return 0; | |
265 | } | |
6da127ad | 266 | EXPORT_SYMBOL_GPL(blk_trace_remove); |
2056a782 JA |
267 | |
268 | static int blk_dropped_open(struct inode *inode, struct file *filp) | |
269 | { | |
8e18e294 | 270 | filp->private_data = inode->i_private; |
2056a782 JA |
271 | |
272 | return 0; | |
273 | } | |
274 | ||
275 | static ssize_t blk_dropped_read(struct file *filp, char __user *buffer, | |
276 | size_t count, loff_t *ppos) | |
277 | { | |
278 | struct blk_trace *bt = filp->private_data; | |
279 | char buf[16]; | |
280 | ||
281 | snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped)); | |
282 | ||
283 | return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf)); | |
284 | } | |
285 | ||
2b8693c0 | 286 | static const struct file_operations blk_dropped_fops = { |
2056a782 JA |
287 | .owner = THIS_MODULE, |
288 | .open = blk_dropped_open, | |
289 | .read = blk_dropped_read, | |
290 | }; | |
291 | ||
292 | /* | |
293 | * Keep track of how many times we encountered a full subbuffer, to aid | |
294 | * the user space app in telling how many lost events there were. | |
295 | */ | |
296 | static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf, | |
297 | void *prev_subbuf, size_t prev_padding) | |
298 | { | |
299 | struct blk_trace *bt; | |
300 | ||
301 | if (!relay_buf_full(buf)) | |
302 | return 1; | |
303 | ||
304 | bt = buf->chan->private_data; | |
305 | atomic_inc(&bt->dropped); | |
306 | return 0; | |
307 | } | |
308 | ||
309 | static int blk_remove_buf_file_callback(struct dentry *dentry) | |
310 | { | |
311 | debugfs_remove(dentry); | |
312 | return 0; | |
313 | } | |
314 | ||
315 | static struct dentry *blk_create_buf_file_callback(const char *filename, | |
316 | struct dentry *parent, | |
317 | int mode, | |
318 | struct rchan_buf *buf, | |
319 | int *is_global) | |
320 | { | |
321 | return debugfs_create_file(filename, mode, parent, buf, | |
322 | &relay_file_operations); | |
323 | } | |
324 | ||
325 | static struct rchan_callbacks blk_relay_callbacks = { | |
326 | .subbuf_start = blk_subbuf_start_callback, | |
327 | .create_buf_file = blk_create_buf_file_callback, | |
328 | .remove_buf_file = blk_remove_buf_file_callback, | |
329 | }; | |
330 | ||
331 | /* | |
332 | * Setup everything required to start tracing | |
333 | */ | |
6da127ad | 334 | int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev, |
171044d4 | 335 | struct blk_user_trace_setup *buts) |
2056a782 | 336 | { |
2056a782 JA |
337 | struct blk_trace *old_bt, *bt = NULL; |
338 | struct dentry *dir = NULL; | |
2056a782 JA |
339 | int ret, i; |
340 | ||
171044d4 | 341 | if (!buts->buf_size || !buts->buf_nr) |
2056a782 JA |
342 | return -EINVAL; |
343 | ||
6da127ad | 344 | strcpy(buts->name, name); |
2056a782 JA |
345 | |
346 | /* | |
347 | * some device names have larger paths - convert the slashes | |
348 | * to underscores for this to work as expected | |
349 | */ | |
171044d4 AB |
350 | for (i = 0; i < strlen(buts->name); i++) |
351 | if (buts->name[i] == '/') | |
352 | buts->name[i] = '_'; | |
2056a782 JA |
353 | |
354 | ret = -ENOMEM; | |
355 | bt = kzalloc(sizeof(*bt), GFP_KERNEL); | |
356 | if (!bt) | |
357 | goto err; | |
358 | ||
359 | bt->sequence = alloc_percpu(unsigned long); | |
360 | if (!bt->sequence) | |
361 | goto err; | |
362 | ||
363 | ret = -ENOENT; | |
171044d4 | 364 | dir = blk_create_tree(buts->name); |
2056a782 JA |
365 | if (!dir) |
366 | goto err; | |
367 | ||
368 | bt->dir = dir; | |
6da127ad | 369 | bt->dev = dev; |
2056a782 JA |
370 | atomic_set(&bt->dropped, 0); |
371 | ||
372 | ret = -EIO; | |
373 | bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt, &blk_dropped_fops); | |
374 | if (!bt->dropped_file) | |
375 | goto err; | |
376 | ||
171044d4 AB |
377 | bt->rchan = relay_open("trace", dir, buts->buf_size, |
378 | buts->buf_nr, &blk_relay_callbacks, bt); | |
2056a782 JA |
379 | if (!bt->rchan) |
380 | goto err; | |
2056a782 | 381 | |
171044d4 | 382 | bt->act_mask = buts->act_mask; |
2056a782 JA |
383 | if (!bt->act_mask) |
384 | bt->act_mask = (u16) -1; | |
385 | ||
171044d4 AB |
386 | bt->start_lba = buts->start_lba; |
387 | bt->end_lba = buts->end_lba; | |
2056a782 JA |
388 | if (!bt->end_lba) |
389 | bt->end_lba = -1ULL; | |
390 | ||
171044d4 | 391 | bt->pid = buts->pid; |
2056a782 JA |
392 | bt->trace_state = Blktrace_setup; |
393 | ||
394 | ret = -EBUSY; | |
395 | old_bt = xchg(&q->blk_trace, bt); | |
396 | if (old_bt) { | |
397 | (void) xchg(&q->blk_trace, old_bt); | |
398 | goto err; | |
399 | } | |
400 | ||
401 | return 0; | |
402 | err: | |
403 | if (dir) | |
404 | blk_remove_tree(dir); | |
405 | if (bt) { | |
406 | if (bt->dropped_file) | |
407 | debugfs_remove(bt->dropped_file); | |
a1205868 | 408 | free_percpu(bt->sequence); |
2056a782 JA |
409 | if (bt->rchan) |
410 | relay_close(bt->rchan); | |
411 | kfree(bt); | |
412 | } | |
413 | return ret; | |
414 | } | |
171044d4 | 415 | |
6da127ad CS |
416 | int blk_trace_setup(struct request_queue *q, char *name, dev_t dev, |
417 | char __user *arg) | |
171044d4 AB |
418 | { |
419 | struct blk_user_trace_setup buts; | |
420 | int ret; | |
421 | ||
422 | ret = copy_from_user(&buts, arg, sizeof(buts)); | |
423 | if (ret) | |
424 | return -EFAULT; | |
425 | ||
6da127ad | 426 | ret = do_blk_trace_setup(q, name, dev, &buts); |
171044d4 AB |
427 | if (ret) |
428 | return ret; | |
429 | ||
430 | if (copy_to_user(arg, &buts, sizeof(buts))) | |
431 | return -EFAULT; | |
432 | ||
433 | return 0; | |
434 | } | |
6da127ad | 435 | EXPORT_SYMBOL_GPL(blk_trace_setup); |
2056a782 | 436 | |
6da127ad | 437 | int blk_trace_startstop(struct request_queue *q, int start) |
2056a782 JA |
438 | { |
439 | struct blk_trace *bt; | |
440 | int ret; | |
441 | ||
442 | if ((bt = q->blk_trace) == NULL) | |
443 | return -EINVAL; | |
444 | ||
445 | /* | |
446 | * For starting a trace, we can transition from a setup or stopped | |
447 | * trace. For stopping a trace, the state must be running | |
448 | */ | |
449 | ret = -EINVAL; | |
450 | if (start) { | |
451 | if (bt->trace_state == Blktrace_setup || | |
452 | bt->trace_state == Blktrace_stopped) { | |
453 | blktrace_seq++; | |
454 | smp_mb(); | |
455 | bt->trace_state = Blktrace_running; | |
be1c6341 OK |
456 | |
457 | trace_note_time(bt); | |
2056a782 JA |
458 | ret = 0; |
459 | } | |
460 | } else { | |
461 | if (bt->trace_state == Blktrace_running) { | |
462 | bt->trace_state = Blktrace_stopped; | |
463 | relay_flush(bt->rchan); | |
464 | ret = 0; | |
465 | } | |
466 | } | |
467 | ||
468 | return ret; | |
469 | } | |
6da127ad | 470 | EXPORT_SYMBOL_GPL(blk_trace_startstop); |
2056a782 JA |
471 | |
472 | /** | |
473 | * blk_trace_ioctl: - handle the ioctls associated with tracing | |
474 | * @bdev: the block device | |
475 | * @cmd: the ioctl cmd | |
476 | * @arg: the argument data, if any | |
477 | * | |
478 | **/ | |
479 | int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg) | |
480 | { | |
165125e1 | 481 | struct request_queue *q; |
2056a782 | 482 | int ret, start = 0; |
6da127ad | 483 | char b[BDEVNAME_SIZE]; |
2056a782 JA |
484 | |
485 | q = bdev_get_queue(bdev); | |
486 | if (!q) | |
487 | return -ENXIO; | |
488 | ||
489 | mutex_lock(&bdev->bd_mutex); | |
490 | ||
491 | switch (cmd) { | |
492 | case BLKTRACESETUP: | |
f36f21ec | 493 | bdevname(bdev, b); |
6da127ad | 494 | ret = blk_trace_setup(q, b, bdev->bd_dev, arg); |
2056a782 JA |
495 | break; |
496 | case BLKTRACESTART: | |
497 | start = 1; | |
498 | case BLKTRACESTOP: | |
499 | ret = blk_trace_startstop(q, start); | |
500 | break; | |
501 | case BLKTRACETEARDOWN: | |
502 | ret = blk_trace_remove(q); | |
503 | break; | |
504 | default: | |
505 | ret = -ENOTTY; | |
506 | break; | |
507 | } | |
508 | ||
509 | mutex_unlock(&bdev->bd_mutex); | |
510 | return ret; | |
511 | } | |
512 | ||
513 | /** | |
514 | * blk_trace_shutdown: - stop and cleanup trace structures | |
515 | * @q: the request queue associated with the device | |
516 | * | |
517 | **/ | |
165125e1 | 518 | void blk_trace_shutdown(struct request_queue *q) |
2056a782 | 519 | { |
6c5c9341 AD |
520 | if (q->blk_trace) { |
521 | blk_trace_startstop(q, 0); | |
522 | blk_trace_remove(q); | |
523 | } | |
2056a782 | 524 | } |