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Commit | Line | Data |
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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> |
5f3ea37c | 26 | #include <trace/block.h> |
939b3669 | 27 | #include <linux/uaccess.h> |
2db270a8 | 28 | #include "trace_output.h" |
2056a782 | 29 | |
2056a782 JA |
30 | static unsigned int blktrace_seq __read_mostly = 1; |
31 | ||
c71a8961 | 32 | static struct trace_array *blk_tr; |
5006ea73 | 33 | static bool blk_tracer_enabled __read_mostly; |
c71a8961 ACM |
34 | |
35 | /* Select an alternative, minimalistic output than the original one */ | |
ef18012b | 36 | #define TRACE_BLK_OPT_CLASSIC 0x1 |
c71a8961 ACM |
37 | |
38 | static struct tracer_opt blk_tracer_opts[] = { | |
39 | /* Default disable the minimalistic output */ | |
157f9c00 | 40 | { TRACER_OPT(blk_classic, TRACE_BLK_OPT_CLASSIC) }, |
c71a8961 ACM |
41 | { } |
42 | }; | |
43 | ||
44 | static struct tracer_flags blk_tracer_flags = { | |
45 | .val = 0, | |
46 | .opts = blk_tracer_opts, | |
47 | }; | |
48 | ||
5f3ea37c | 49 | /* Global reference count of probes */ |
5f3ea37c ACM |
50 | static atomic_t blk_probes_ref = ATOMIC_INIT(0); |
51 | ||
3c289ba7 | 52 | static void blk_register_tracepoints(void); |
5f3ea37c ACM |
53 | static void blk_unregister_tracepoints(void); |
54 | ||
be1c6341 OK |
55 | /* |
56 | * Send out a notify message. | |
57 | */ | |
a863055b JA |
58 | static void trace_note(struct blk_trace *bt, pid_t pid, int action, |
59 | const void *data, size_t len) | |
be1c6341 OK |
60 | { |
61 | struct blk_io_trace *t; | |
be1c6341 | 62 | |
c71a8961 ACM |
63 | if (!bt->rchan) |
64 | return; | |
65 | ||
be1c6341 | 66 | t = relay_reserve(bt->rchan, sizeof(*t) + len); |
d3d9d2a5 JA |
67 | if (t) { |
68 | const int cpu = smp_processor_id(); | |
69 | ||
70 | t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION; | |
2997c8c4 | 71 | t->time = ktime_to_ns(ktime_get()); |
d3d9d2a5 JA |
72 | t->device = bt->dev; |
73 | t->action = action; | |
74 | t->pid = pid; | |
75 | t->cpu = cpu; | |
76 | t->pdu_len = len; | |
77 | memcpy((void *) t + sizeof(*t), data, len); | |
78 | } | |
be1c6341 OK |
79 | } |
80 | ||
2056a782 JA |
81 | /* |
82 | * Send out a notify for this process, if we haven't done so since a trace | |
83 | * started | |
84 | */ | |
85 | static void trace_note_tsk(struct blk_trace *bt, struct task_struct *tsk) | |
86 | { | |
a863055b JA |
87 | tsk->btrace_seq = blktrace_seq; |
88 | trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm, sizeof(tsk->comm)); | |
be1c6341 | 89 | } |
2056a782 | 90 | |
be1c6341 OK |
91 | static void trace_note_time(struct blk_trace *bt) |
92 | { | |
93 | struct timespec now; | |
94 | unsigned long flags; | |
95 | u32 words[2]; | |
96 | ||
97 | getnstimeofday(&now); | |
98 | words[0] = now.tv_sec; | |
99 | words[1] = now.tv_nsec; | |
100 | ||
101 | local_irq_save(flags); | |
102 | trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words)); | |
103 | local_irq_restore(flags); | |
2056a782 JA |
104 | } |
105 | ||
9d5f09a4 AB |
106 | void __trace_note_message(struct blk_trace *bt, const char *fmt, ...) |
107 | { | |
108 | int n; | |
109 | va_list args; | |
14a73f54 | 110 | unsigned long flags; |
64565911 | 111 | char *buf; |
9d5f09a4 | 112 | |
c71a8961 ACM |
113 | if (blk_tr) { |
114 | va_start(args, fmt); | |
115 | ftrace_vprintk(fmt, args); | |
116 | va_end(args); | |
117 | return; | |
118 | } | |
119 | ||
120 | if (!bt->msg_data) | |
121 | return; | |
122 | ||
14a73f54 | 123 | local_irq_save(flags); |
64565911 | 124 | buf = per_cpu_ptr(bt->msg_data, smp_processor_id()); |
9d5f09a4 | 125 | va_start(args, fmt); |
64565911 | 126 | n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args); |
9d5f09a4 AB |
127 | va_end(args); |
128 | ||
64565911 | 129 | trace_note(bt, 0, BLK_TN_MESSAGE, buf, n); |
14a73f54 | 130 | local_irq_restore(flags); |
9d5f09a4 AB |
131 | } |
132 | EXPORT_SYMBOL_GPL(__trace_note_message); | |
133 | ||
2056a782 JA |
134 | static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector, |
135 | pid_t pid) | |
136 | { | |
137 | if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0) | |
138 | return 1; | |
139 | if (sector < bt->start_lba || sector > bt->end_lba) | |
140 | return 1; | |
141 | if (bt->pid && pid != bt->pid) | |
142 | return 1; | |
143 | ||
144 | return 0; | |
145 | } | |
146 | ||
147 | /* | |
148 | * Data direction bit lookup | |
149 | */ | |
939b3669 ACM |
150 | static u32 ddir_act[2] __read_mostly = { BLK_TC_ACT(BLK_TC_READ), |
151 | BLK_TC_ACT(BLK_TC_WRITE) }; | |
2056a782 | 152 | |
35ba8f70 | 153 | /* The ilog2() calls fall out because they're constant */ |
939b3669 ACM |
154 | #define MASK_TC_BIT(rw, __name) ((rw & (1 << BIO_RW_ ## __name)) << \ |
155 | (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - BIO_RW_ ## __name)) | |
2056a782 JA |
156 | |
157 | /* | |
158 | * The worker for the various blk_add_trace*() types. Fills out a | |
159 | * blk_io_trace structure and places it in a per-cpu subbuffer. | |
160 | */ | |
5f3ea37c | 161 | static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes, |
2056a782 JA |
162 | int rw, u32 what, int error, int pdu_len, void *pdu_data) |
163 | { | |
164 | struct task_struct *tsk = current; | |
c71a8961 | 165 | struct ring_buffer_event *event = NULL; |
2056a782 | 166 | struct blk_io_trace *t; |
0a987751 | 167 | unsigned long flags = 0; |
2056a782 JA |
168 | unsigned long *sequence; |
169 | pid_t pid; | |
c71a8961 | 170 | int cpu, pc = 0; |
2056a782 | 171 | |
157f9c00 ACM |
172 | if (unlikely(bt->trace_state != Blktrace_running || |
173 | !blk_tracer_enabled)) | |
2056a782 JA |
174 | return; |
175 | ||
176 | what |= ddir_act[rw & WRITE]; | |
35ba8f70 | 177 | what |= MASK_TC_BIT(rw, BARRIER); |
93dbb393 | 178 | what |= MASK_TC_BIT(rw, SYNCIO); |
35ba8f70 DW |
179 | what |= MASK_TC_BIT(rw, AHEAD); |
180 | what |= MASK_TC_BIT(rw, META); | |
181 | what |= MASK_TC_BIT(rw, DISCARD); | |
2056a782 JA |
182 | |
183 | pid = tsk->pid; | |
184 | if (unlikely(act_log_check(bt, what, sector, pid))) | |
185 | return; | |
c71a8961 ACM |
186 | cpu = raw_smp_processor_id(); |
187 | ||
188 | if (blk_tr) { | |
c71a8961 ACM |
189 | tracing_record_cmdline(current); |
190 | ||
51a763dd ACM |
191 | pc = preempt_count(); |
192 | event = trace_buffer_lock_reserve(blk_tr, TRACE_BLK, | |
193 | sizeof(*t) + pdu_len, | |
194 | 0, pc); | |
c71a8961 ACM |
195 | if (!event) |
196 | return; | |
51a763dd | 197 | t = ring_buffer_event_data(event); |
c71a8961 ACM |
198 | goto record_it; |
199 | } | |
2056a782 JA |
200 | |
201 | /* | |
202 | * A word about the locking here - we disable interrupts to reserve | |
203 | * some space in the relay per-cpu buffer, to prevent an irq | |
14a73f54 | 204 | * from coming in and stepping on our toes. |
2056a782 JA |
205 | */ |
206 | local_irq_save(flags); | |
207 | ||
208 | if (unlikely(tsk->btrace_seq != blktrace_seq)) | |
209 | trace_note_tsk(bt, tsk); | |
210 | ||
211 | t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len); | |
212 | if (t) { | |
2056a782 JA |
213 | sequence = per_cpu_ptr(bt->sequence, cpu); |
214 | ||
215 | t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION; | |
216 | t->sequence = ++(*sequence); | |
2997c8c4 | 217 | t->time = ktime_to_ns(ktime_get()); |
c71a8961 | 218 | record_it: |
08a06b83 | 219 | /* |
939b3669 ACM |
220 | * These two are not needed in ftrace as they are in the |
221 | * generic trace_entry, filled by tracing_generic_entry_update, | |
222 | * but for the trace_event->bin() synthesizer benefit we do it | |
223 | * here too. | |
224 | */ | |
225 | t->cpu = cpu; | |
226 | t->pid = pid; | |
08a06b83 | 227 | |
2056a782 JA |
228 | t->sector = sector; |
229 | t->bytes = bytes; | |
230 | t->action = what; | |
2056a782 | 231 | t->device = bt->dev; |
2056a782 JA |
232 | t->error = error; |
233 | t->pdu_len = pdu_len; | |
234 | ||
235 | if (pdu_len) | |
236 | memcpy((void *) t + sizeof(*t), pdu_data, pdu_len); | |
c71a8961 ACM |
237 | |
238 | if (blk_tr) { | |
51a763dd | 239 | trace_buffer_unlock_commit(blk_tr, event, 0, pc); |
c71a8961 ACM |
240 | return; |
241 | } | |
2056a782 JA |
242 | } |
243 | ||
244 | local_irq_restore(flags); | |
245 | } | |
246 | ||
2056a782 | 247 | static struct dentry *blk_tree_root; |
11a57153 | 248 | static DEFINE_MUTEX(blk_tree_mutex); |
2056a782 JA |
249 | |
250 | static void blk_trace_cleanup(struct blk_trace *bt) | |
251 | { | |
02c62304 | 252 | debugfs_remove(bt->msg_file); |
2056a782 | 253 | debugfs_remove(bt->dropped_file); |
f48fc4d3 | 254 | relay_close(bt->rchan); |
2056a782 | 255 | free_percpu(bt->sequence); |
64565911 | 256 | free_percpu(bt->msg_data); |
2056a782 | 257 | kfree(bt); |
5f3ea37c ACM |
258 | if (atomic_dec_and_test(&blk_probes_ref)) |
259 | blk_unregister_tracepoints(); | |
2056a782 JA |
260 | } |
261 | ||
6da127ad | 262 | int blk_trace_remove(struct request_queue *q) |
2056a782 JA |
263 | { |
264 | struct blk_trace *bt; | |
265 | ||
266 | bt = xchg(&q->blk_trace, NULL); | |
267 | if (!bt) | |
268 | return -EINVAL; | |
269 | ||
270 | if (bt->trace_state == Blktrace_setup || | |
271 | bt->trace_state == Blktrace_stopped) | |
272 | blk_trace_cleanup(bt); | |
273 | ||
274 | return 0; | |
275 | } | |
6da127ad | 276 | EXPORT_SYMBOL_GPL(blk_trace_remove); |
2056a782 JA |
277 | |
278 | static int blk_dropped_open(struct inode *inode, struct file *filp) | |
279 | { | |
8e18e294 | 280 | filp->private_data = inode->i_private; |
2056a782 JA |
281 | |
282 | return 0; | |
283 | } | |
284 | ||
285 | static ssize_t blk_dropped_read(struct file *filp, char __user *buffer, | |
286 | size_t count, loff_t *ppos) | |
287 | { | |
288 | struct blk_trace *bt = filp->private_data; | |
289 | char buf[16]; | |
290 | ||
291 | snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped)); | |
292 | ||
293 | return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf)); | |
294 | } | |
295 | ||
2b8693c0 | 296 | static const struct file_operations blk_dropped_fops = { |
2056a782 JA |
297 | .owner = THIS_MODULE, |
298 | .open = blk_dropped_open, | |
299 | .read = blk_dropped_read, | |
300 | }; | |
301 | ||
02c62304 AB |
302 | static int blk_msg_open(struct inode *inode, struct file *filp) |
303 | { | |
304 | filp->private_data = inode->i_private; | |
305 | ||
306 | return 0; | |
307 | } | |
308 | ||
309 | static ssize_t blk_msg_write(struct file *filp, const char __user *buffer, | |
310 | size_t count, loff_t *ppos) | |
311 | { | |
312 | char *msg; | |
313 | struct blk_trace *bt; | |
314 | ||
315 | if (count > BLK_TN_MAX_MSG) | |
316 | return -EINVAL; | |
317 | ||
318 | msg = kmalloc(count, GFP_KERNEL); | |
319 | if (msg == NULL) | |
320 | return -ENOMEM; | |
321 | ||
322 | if (copy_from_user(msg, buffer, count)) { | |
323 | kfree(msg); | |
324 | return -EFAULT; | |
325 | } | |
326 | ||
327 | bt = filp->private_data; | |
328 | __trace_note_message(bt, "%s", msg); | |
329 | kfree(msg); | |
330 | ||
331 | return count; | |
332 | } | |
333 | ||
334 | static const struct file_operations blk_msg_fops = { | |
335 | .owner = THIS_MODULE, | |
336 | .open = blk_msg_open, | |
337 | .write = blk_msg_write, | |
338 | }; | |
339 | ||
2056a782 JA |
340 | /* |
341 | * Keep track of how many times we encountered a full subbuffer, to aid | |
342 | * the user space app in telling how many lost events there were. | |
343 | */ | |
344 | static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf, | |
345 | void *prev_subbuf, size_t prev_padding) | |
346 | { | |
347 | struct blk_trace *bt; | |
348 | ||
349 | if (!relay_buf_full(buf)) | |
350 | return 1; | |
351 | ||
352 | bt = buf->chan->private_data; | |
353 | atomic_inc(&bt->dropped); | |
354 | return 0; | |
355 | } | |
356 | ||
357 | static int blk_remove_buf_file_callback(struct dentry *dentry) | |
358 | { | |
f48fc4d3 | 359 | struct dentry *parent = dentry->d_parent; |
2056a782 | 360 | debugfs_remove(dentry); |
f48fc4d3 JA |
361 | |
362 | /* | |
363 | * this will fail for all but the last file, but that is ok. what we | |
364 | * care about is the top level buts->name directory going away, when | |
365 | * the last trace file is gone. Then we don't have to rmdir() that | |
366 | * manually on trace stop, so it nicely solves the issue with | |
367 | * force killing of running traces. | |
368 | */ | |
369 | ||
370 | debugfs_remove(parent); | |
2056a782 JA |
371 | return 0; |
372 | } | |
373 | ||
374 | static struct dentry *blk_create_buf_file_callback(const char *filename, | |
375 | struct dentry *parent, | |
376 | int mode, | |
377 | struct rchan_buf *buf, | |
378 | int *is_global) | |
379 | { | |
380 | return debugfs_create_file(filename, mode, parent, buf, | |
381 | &relay_file_operations); | |
382 | } | |
383 | ||
384 | static struct rchan_callbacks blk_relay_callbacks = { | |
385 | .subbuf_start = blk_subbuf_start_callback, | |
386 | .create_buf_file = blk_create_buf_file_callback, | |
387 | .remove_buf_file = blk_remove_buf_file_callback, | |
388 | }; | |
389 | ||
390 | /* | |
391 | * Setup everything required to start tracing | |
392 | */ | |
6da127ad | 393 | int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev, |
171044d4 | 394 | struct blk_user_trace_setup *buts) |
2056a782 | 395 | { |
2056a782 JA |
396 | struct blk_trace *old_bt, *bt = NULL; |
397 | struct dentry *dir = NULL; | |
2056a782 JA |
398 | int ret, i; |
399 | ||
171044d4 | 400 | if (!buts->buf_size || !buts->buf_nr) |
2056a782 JA |
401 | return -EINVAL; |
402 | ||
0497b345 JA |
403 | strncpy(buts->name, name, BLKTRACE_BDEV_SIZE); |
404 | buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0'; | |
2056a782 JA |
405 | |
406 | /* | |
407 | * some device names have larger paths - convert the slashes | |
408 | * to underscores for this to work as expected | |
409 | */ | |
171044d4 AB |
410 | for (i = 0; i < strlen(buts->name); i++) |
411 | if (buts->name[i] == '/') | |
412 | buts->name[i] = '_'; | |
2056a782 JA |
413 | |
414 | ret = -ENOMEM; | |
415 | bt = kzalloc(sizeof(*bt), GFP_KERNEL); | |
416 | if (!bt) | |
417 | goto err; | |
418 | ||
419 | bt->sequence = alloc_percpu(unsigned long); | |
420 | if (!bt->sequence) | |
421 | goto err; | |
422 | ||
313e458f | 423 | bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char)); |
64565911 JA |
424 | if (!bt->msg_data) |
425 | goto err; | |
426 | ||
2056a782 | 427 | ret = -ENOENT; |
f48fc4d3 JA |
428 | |
429 | if (!blk_tree_root) { | |
430 | blk_tree_root = debugfs_create_dir("block", NULL); | |
431 | if (!blk_tree_root) | |
1a17662e | 432 | goto err; |
f48fc4d3 JA |
433 | } |
434 | ||
435 | dir = debugfs_create_dir(buts->name, blk_tree_root); | |
436 | ||
2056a782 JA |
437 | if (!dir) |
438 | goto err; | |
439 | ||
440 | bt->dir = dir; | |
6da127ad | 441 | bt->dev = dev; |
2056a782 JA |
442 | atomic_set(&bt->dropped, 0); |
443 | ||
444 | ret = -EIO; | |
939b3669 ACM |
445 | bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt, |
446 | &blk_dropped_fops); | |
2056a782 JA |
447 | if (!bt->dropped_file) |
448 | goto err; | |
449 | ||
02c62304 AB |
450 | bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops); |
451 | if (!bt->msg_file) | |
452 | goto err; | |
453 | ||
171044d4 AB |
454 | bt->rchan = relay_open("trace", dir, buts->buf_size, |
455 | buts->buf_nr, &blk_relay_callbacks, bt); | |
2056a782 JA |
456 | if (!bt->rchan) |
457 | goto err; | |
2056a782 | 458 | |
171044d4 | 459 | bt->act_mask = buts->act_mask; |
2056a782 JA |
460 | if (!bt->act_mask) |
461 | bt->act_mask = (u16) -1; | |
462 | ||
171044d4 AB |
463 | bt->start_lba = buts->start_lba; |
464 | bt->end_lba = buts->end_lba; | |
2056a782 JA |
465 | if (!bt->end_lba) |
466 | bt->end_lba = -1ULL; | |
467 | ||
171044d4 | 468 | bt->pid = buts->pid; |
2056a782 JA |
469 | bt->trace_state = Blktrace_setup; |
470 | ||
471 | ret = -EBUSY; | |
472 | old_bt = xchg(&q->blk_trace, bt); | |
473 | if (old_bt) { | |
474 | (void) xchg(&q->blk_trace, old_bt); | |
475 | goto err; | |
476 | } | |
477 | ||
cbe28296 LZ |
478 | if (atomic_add_return(1, &blk_probes_ref) == 1) |
479 | blk_register_tracepoints(); | |
480 | ||
2056a782 JA |
481 | return 0; |
482 | err: | |
2056a782 | 483 | if (bt) { |
02c62304 AB |
484 | if (bt->msg_file) |
485 | debugfs_remove(bt->msg_file); | |
2056a782 JA |
486 | if (bt->dropped_file) |
487 | debugfs_remove(bt->dropped_file); | |
a1205868 | 488 | free_percpu(bt->sequence); |
64565911 | 489 | free_percpu(bt->msg_data); |
2056a782 JA |
490 | if (bt->rchan) |
491 | relay_close(bt->rchan); | |
492 | kfree(bt); | |
493 | } | |
494 | return ret; | |
495 | } | |
171044d4 | 496 | |
6da127ad CS |
497 | int blk_trace_setup(struct request_queue *q, char *name, dev_t dev, |
498 | char __user *arg) | |
171044d4 AB |
499 | { |
500 | struct blk_user_trace_setup buts; | |
501 | int ret; | |
502 | ||
503 | ret = copy_from_user(&buts, arg, sizeof(buts)); | |
504 | if (ret) | |
505 | return -EFAULT; | |
506 | ||
6da127ad | 507 | ret = do_blk_trace_setup(q, name, dev, &buts); |
171044d4 AB |
508 | if (ret) |
509 | return ret; | |
510 | ||
511 | if (copy_to_user(arg, &buts, sizeof(buts))) | |
512 | return -EFAULT; | |
513 | ||
514 | return 0; | |
515 | } | |
6da127ad | 516 | EXPORT_SYMBOL_GPL(blk_trace_setup); |
2056a782 | 517 | |
6da127ad | 518 | int blk_trace_startstop(struct request_queue *q, int start) |
2056a782 | 519 | { |
2056a782 | 520 | int ret; |
939b3669 | 521 | struct blk_trace *bt = q->blk_trace; |
2056a782 | 522 | |
939b3669 | 523 | if (bt == NULL) |
2056a782 JA |
524 | return -EINVAL; |
525 | ||
526 | /* | |
527 | * For starting a trace, we can transition from a setup or stopped | |
528 | * trace. For stopping a trace, the state must be running | |
529 | */ | |
530 | ret = -EINVAL; | |
531 | if (start) { | |
532 | if (bt->trace_state == Blktrace_setup || | |
533 | bt->trace_state == Blktrace_stopped) { | |
534 | blktrace_seq++; | |
535 | smp_mb(); | |
536 | bt->trace_state = Blktrace_running; | |
be1c6341 OK |
537 | |
538 | trace_note_time(bt); | |
2056a782 JA |
539 | ret = 0; |
540 | } | |
541 | } else { | |
542 | if (bt->trace_state == Blktrace_running) { | |
543 | bt->trace_state = Blktrace_stopped; | |
544 | relay_flush(bt->rchan); | |
545 | ret = 0; | |
546 | } | |
547 | } | |
548 | ||
549 | return ret; | |
550 | } | |
6da127ad | 551 | EXPORT_SYMBOL_GPL(blk_trace_startstop); |
2056a782 JA |
552 | |
553 | /** | |
554 | * blk_trace_ioctl: - handle the ioctls associated with tracing | |
555 | * @bdev: the block device | |
ef18012b | 556 | * @cmd: the ioctl cmd |
2056a782 JA |
557 | * @arg: the argument data, if any |
558 | * | |
559 | **/ | |
560 | int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg) | |
561 | { | |
165125e1 | 562 | struct request_queue *q; |
2056a782 | 563 | int ret, start = 0; |
6da127ad | 564 | char b[BDEVNAME_SIZE]; |
2056a782 JA |
565 | |
566 | q = bdev_get_queue(bdev); | |
567 | if (!q) | |
568 | return -ENXIO; | |
569 | ||
570 | mutex_lock(&bdev->bd_mutex); | |
571 | ||
572 | switch (cmd) { | |
573 | case BLKTRACESETUP: | |
f36f21ec | 574 | bdevname(bdev, b); |
6da127ad | 575 | ret = blk_trace_setup(q, b, bdev->bd_dev, arg); |
2056a782 JA |
576 | break; |
577 | case BLKTRACESTART: | |
578 | start = 1; | |
579 | case BLKTRACESTOP: | |
580 | ret = blk_trace_startstop(q, start); | |
581 | break; | |
582 | case BLKTRACETEARDOWN: | |
583 | ret = blk_trace_remove(q); | |
584 | break; | |
585 | default: | |
586 | ret = -ENOTTY; | |
587 | break; | |
588 | } | |
589 | ||
590 | mutex_unlock(&bdev->bd_mutex); | |
591 | return ret; | |
592 | } | |
593 | ||
594 | /** | |
595 | * blk_trace_shutdown: - stop and cleanup trace structures | |
596 | * @q: the request queue associated with the device | |
597 | * | |
598 | **/ | |
165125e1 | 599 | void blk_trace_shutdown(struct request_queue *q) |
2056a782 | 600 | { |
6c5c9341 AD |
601 | if (q->blk_trace) { |
602 | blk_trace_startstop(q, 0); | |
603 | blk_trace_remove(q); | |
604 | } | |
2056a782 | 605 | } |
5f3ea37c ACM |
606 | |
607 | /* | |
608 | * blktrace probes | |
609 | */ | |
610 | ||
611 | /** | |
612 | * blk_add_trace_rq - Add a trace for a request oriented action | |
613 | * @q: queue the io is for | |
614 | * @rq: the source request | |
615 | * @what: the action | |
616 | * | |
617 | * Description: | |
618 | * Records an action against a request. Will log the bio offset + size. | |
619 | * | |
620 | **/ | |
621 | static void blk_add_trace_rq(struct request_queue *q, struct request *rq, | |
622 | u32 what) | |
623 | { | |
624 | struct blk_trace *bt = q->blk_trace; | |
625 | int rw = rq->cmd_flags & 0x03; | |
626 | ||
627 | if (likely(!bt)) | |
628 | return; | |
629 | ||
630 | if (blk_discard_rq(rq)) | |
631 | rw |= (1 << BIO_RW_DISCARD); | |
632 | ||
633 | if (blk_pc_request(rq)) { | |
634 | what |= BLK_TC_ACT(BLK_TC_PC); | |
635 | __blk_add_trace(bt, 0, rq->data_len, rw, what, rq->errors, | |
636 | sizeof(rq->cmd), rq->cmd); | |
637 | } else { | |
638 | what |= BLK_TC_ACT(BLK_TC_FS); | |
639 | __blk_add_trace(bt, rq->hard_sector, rq->hard_nr_sectors << 9, | |
640 | rw, what, rq->errors, 0, NULL); | |
641 | } | |
642 | } | |
643 | ||
644 | static void blk_add_trace_rq_abort(struct request_queue *q, struct request *rq) | |
645 | { | |
646 | blk_add_trace_rq(q, rq, BLK_TA_ABORT); | |
647 | } | |
648 | ||
649 | static void blk_add_trace_rq_insert(struct request_queue *q, struct request *rq) | |
650 | { | |
651 | blk_add_trace_rq(q, rq, BLK_TA_INSERT); | |
652 | } | |
653 | ||
654 | static void blk_add_trace_rq_issue(struct request_queue *q, struct request *rq) | |
655 | { | |
656 | blk_add_trace_rq(q, rq, BLK_TA_ISSUE); | |
657 | } | |
658 | ||
939b3669 ACM |
659 | static void blk_add_trace_rq_requeue(struct request_queue *q, |
660 | struct request *rq) | |
5f3ea37c ACM |
661 | { |
662 | blk_add_trace_rq(q, rq, BLK_TA_REQUEUE); | |
663 | } | |
664 | ||
939b3669 ACM |
665 | static void blk_add_trace_rq_complete(struct request_queue *q, |
666 | struct request *rq) | |
5f3ea37c ACM |
667 | { |
668 | blk_add_trace_rq(q, rq, BLK_TA_COMPLETE); | |
669 | } | |
670 | ||
671 | /** | |
672 | * blk_add_trace_bio - Add a trace for a bio oriented action | |
673 | * @q: queue the io is for | |
674 | * @bio: the source bio | |
675 | * @what: the action | |
676 | * | |
677 | * Description: | |
678 | * Records an action against a bio. Will log the bio offset + size. | |
679 | * | |
680 | **/ | |
681 | static void blk_add_trace_bio(struct request_queue *q, struct bio *bio, | |
682 | u32 what) | |
683 | { | |
684 | struct blk_trace *bt = q->blk_trace; | |
685 | ||
686 | if (likely(!bt)) | |
687 | return; | |
688 | ||
689 | __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, what, | |
690 | !bio_flagged(bio, BIO_UPTODATE), 0, NULL); | |
691 | } | |
692 | ||
693 | static void blk_add_trace_bio_bounce(struct request_queue *q, struct bio *bio) | |
694 | { | |
695 | blk_add_trace_bio(q, bio, BLK_TA_BOUNCE); | |
696 | } | |
697 | ||
698 | static void blk_add_trace_bio_complete(struct request_queue *q, struct bio *bio) | |
699 | { | |
700 | blk_add_trace_bio(q, bio, BLK_TA_COMPLETE); | |
701 | } | |
702 | ||
939b3669 ACM |
703 | static void blk_add_trace_bio_backmerge(struct request_queue *q, |
704 | struct bio *bio) | |
5f3ea37c ACM |
705 | { |
706 | blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE); | |
707 | } | |
708 | ||
939b3669 ACM |
709 | static void blk_add_trace_bio_frontmerge(struct request_queue *q, |
710 | struct bio *bio) | |
5f3ea37c ACM |
711 | { |
712 | blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE); | |
713 | } | |
714 | ||
715 | static void blk_add_trace_bio_queue(struct request_queue *q, struct bio *bio) | |
716 | { | |
717 | blk_add_trace_bio(q, bio, BLK_TA_QUEUE); | |
718 | } | |
719 | ||
939b3669 ACM |
720 | static void blk_add_trace_getrq(struct request_queue *q, |
721 | struct bio *bio, int rw) | |
5f3ea37c ACM |
722 | { |
723 | if (bio) | |
724 | blk_add_trace_bio(q, bio, BLK_TA_GETRQ); | |
725 | else { | |
726 | struct blk_trace *bt = q->blk_trace; | |
727 | ||
728 | if (bt) | |
729 | __blk_add_trace(bt, 0, 0, rw, BLK_TA_GETRQ, 0, 0, NULL); | |
730 | } | |
731 | } | |
732 | ||
733 | ||
939b3669 ACM |
734 | static void blk_add_trace_sleeprq(struct request_queue *q, |
735 | struct bio *bio, int rw) | |
5f3ea37c ACM |
736 | { |
737 | if (bio) | |
738 | blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ); | |
739 | else { | |
740 | struct blk_trace *bt = q->blk_trace; | |
741 | ||
742 | if (bt) | |
939b3669 ACM |
743 | __blk_add_trace(bt, 0, 0, rw, BLK_TA_SLEEPRQ, |
744 | 0, 0, NULL); | |
5f3ea37c ACM |
745 | } |
746 | } | |
747 | ||
748 | static void blk_add_trace_plug(struct request_queue *q) | |
749 | { | |
750 | struct blk_trace *bt = q->blk_trace; | |
751 | ||
752 | if (bt) | |
753 | __blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL); | |
754 | } | |
755 | ||
756 | static void blk_add_trace_unplug_io(struct request_queue *q) | |
757 | { | |
758 | struct blk_trace *bt = q->blk_trace; | |
759 | ||
760 | if (bt) { | |
761 | unsigned int pdu = q->rq.count[READ] + q->rq.count[WRITE]; | |
762 | __be64 rpdu = cpu_to_be64(pdu); | |
763 | ||
764 | __blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_IO, 0, | |
765 | sizeof(rpdu), &rpdu); | |
766 | } | |
767 | } | |
768 | ||
769 | static void blk_add_trace_unplug_timer(struct request_queue *q) | |
770 | { | |
771 | struct blk_trace *bt = q->blk_trace; | |
772 | ||
773 | if (bt) { | |
774 | unsigned int pdu = q->rq.count[READ] + q->rq.count[WRITE]; | |
775 | __be64 rpdu = cpu_to_be64(pdu); | |
776 | ||
777 | __blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_TIMER, 0, | |
778 | sizeof(rpdu), &rpdu); | |
779 | } | |
780 | } | |
781 | ||
782 | static void blk_add_trace_split(struct request_queue *q, struct bio *bio, | |
783 | unsigned int pdu) | |
784 | { | |
785 | struct blk_trace *bt = q->blk_trace; | |
786 | ||
787 | if (bt) { | |
788 | __be64 rpdu = cpu_to_be64(pdu); | |
789 | ||
790 | __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, | |
791 | BLK_TA_SPLIT, !bio_flagged(bio, BIO_UPTODATE), | |
792 | sizeof(rpdu), &rpdu); | |
793 | } | |
794 | } | |
795 | ||
796 | /** | |
797 | * blk_add_trace_remap - Add a trace for a remap operation | |
798 | * @q: queue the io is for | |
799 | * @bio: the source bio | |
800 | * @dev: target device | |
801 | * @from: source sector | |
802 | * @to: target sector | |
803 | * | |
804 | * Description: | |
805 | * Device mapper or raid target sometimes need to split a bio because | |
806 | * it spans a stripe (or similar). Add a trace for that action. | |
807 | * | |
808 | **/ | |
809 | static void blk_add_trace_remap(struct request_queue *q, struct bio *bio, | |
810 | dev_t dev, sector_t from, sector_t to) | |
811 | { | |
812 | struct blk_trace *bt = q->blk_trace; | |
813 | struct blk_io_trace_remap r; | |
814 | ||
815 | if (likely(!bt)) | |
816 | return; | |
817 | ||
818 | r.device = cpu_to_be32(dev); | |
819 | r.device_from = cpu_to_be32(bio->bi_bdev->bd_dev); | |
820 | r.sector = cpu_to_be64(to); | |
821 | ||
822 | __blk_add_trace(bt, from, bio->bi_size, bio->bi_rw, BLK_TA_REMAP, | |
823 | !bio_flagged(bio, BIO_UPTODATE), sizeof(r), &r); | |
824 | } | |
825 | ||
826 | /** | |
827 | * blk_add_driver_data - Add binary message with driver-specific data | |
828 | * @q: queue the io is for | |
829 | * @rq: io request | |
830 | * @data: driver-specific data | |
831 | * @len: length of driver-specific data | |
832 | * | |
833 | * Description: | |
834 | * Some drivers might want to write driver-specific data per request. | |
835 | * | |
836 | **/ | |
837 | void blk_add_driver_data(struct request_queue *q, | |
838 | struct request *rq, | |
839 | void *data, size_t len) | |
840 | { | |
841 | struct blk_trace *bt = q->blk_trace; | |
842 | ||
843 | if (likely(!bt)) | |
844 | return; | |
845 | ||
846 | if (blk_pc_request(rq)) | |
847 | __blk_add_trace(bt, 0, rq->data_len, 0, BLK_TA_DRV_DATA, | |
848 | rq->errors, len, data); | |
849 | else | |
850 | __blk_add_trace(bt, rq->hard_sector, rq->hard_nr_sectors << 9, | |
851 | 0, BLK_TA_DRV_DATA, rq->errors, len, data); | |
852 | } | |
853 | EXPORT_SYMBOL_GPL(blk_add_driver_data); | |
854 | ||
3c289ba7 | 855 | static void blk_register_tracepoints(void) |
5f3ea37c ACM |
856 | { |
857 | int ret; | |
858 | ||
859 | ret = register_trace_block_rq_abort(blk_add_trace_rq_abort); | |
860 | WARN_ON(ret); | |
861 | ret = register_trace_block_rq_insert(blk_add_trace_rq_insert); | |
862 | WARN_ON(ret); | |
863 | ret = register_trace_block_rq_issue(blk_add_trace_rq_issue); | |
864 | WARN_ON(ret); | |
865 | ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue); | |
866 | WARN_ON(ret); | |
867 | ret = register_trace_block_rq_complete(blk_add_trace_rq_complete); | |
868 | WARN_ON(ret); | |
869 | ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce); | |
870 | WARN_ON(ret); | |
871 | ret = register_trace_block_bio_complete(blk_add_trace_bio_complete); | |
872 | WARN_ON(ret); | |
873 | ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge); | |
874 | WARN_ON(ret); | |
875 | ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge); | |
876 | WARN_ON(ret); | |
877 | ret = register_trace_block_bio_queue(blk_add_trace_bio_queue); | |
878 | WARN_ON(ret); | |
879 | ret = register_trace_block_getrq(blk_add_trace_getrq); | |
880 | WARN_ON(ret); | |
881 | ret = register_trace_block_sleeprq(blk_add_trace_sleeprq); | |
882 | WARN_ON(ret); | |
883 | ret = register_trace_block_plug(blk_add_trace_plug); | |
884 | WARN_ON(ret); | |
885 | ret = register_trace_block_unplug_timer(blk_add_trace_unplug_timer); | |
886 | WARN_ON(ret); | |
887 | ret = register_trace_block_unplug_io(blk_add_trace_unplug_io); | |
888 | WARN_ON(ret); | |
889 | ret = register_trace_block_split(blk_add_trace_split); | |
890 | WARN_ON(ret); | |
891 | ret = register_trace_block_remap(blk_add_trace_remap); | |
892 | WARN_ON(ret); | |
5f3ea37c ACM |
893 | } |
894 | ||
895 | static void blk_unregister_tracepoints(void) | |
896 | { | |
897 | unregister_trace_block_remap(blk_add_trace_remap); | |
898 | unregister_trace_block_split(blk_add_trace_split); | |
899 | unregister_trace_block_unplug_io(blk_add_trace_unplug_io); | |
900 | unregister_trace_block_unplug_timer(blk_add_trace_unplug_timer); | |
901 | unregister_trace_block_plug(blk_add_trace_plug); | |
902 | unregister_trace_block_sleeprq(blk_add_trace_sleeprq); | |
903 | unregister_trace_block_getrq(blk_add_trace_getrq); | |
904 | unregister_trace_block_bio_queue(blk_add_trace_bio_queue); | |
905 | unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge); | |
906 | unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge); | |
907 | unregister_trace_block_bio_complete(blk_add_trace_bio_complete); | |
908 | unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce); | |
909 | unregister_trace_block_rq_complete(blk_add_trace_rq_complete); | |
910 | unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue); | |
911 | unregister_trace_block_rq_issue(blk_add_trace_rq_issue); | |
912 | unregister_trace_block_rq_insert(blk_add_trace_rq_insert); | |
913 | unregister_trace_block_rq_abort(blk_add_trace_rq_abort); | |
914 | ||
915 | tracepoint_synchronize_unregister(); | |
916 | } | |
c71a8961 ACM |
917 | |
918 | /* | |
919 | * struct blk_io_tracer formatting routines | |
920 | */ | |
921 | ||
922 | static void fill_rwbs(char *rwbs, const struct blk_io_trace *t) | |
923 | { | |
157f9c00 ACM |
924 | int i = 0; |
925 | ||
926 | if (t->action & BLK_TC_DISCARD) | |
927 | rwbs[i++] = 'D'; | |
928 | else if (t->action & BLK_TC_WRITE) | |
929 | rwbs[i++] = 'W'; | |
930 | else if (t->bytes) | |
931 | rwbs[i++] = 'R'; | |
932 | else | |
933 | rwbs[i++] = 'N'; | |
934 | ||
935 | if (t->action & BLK_TC_AHEAD) | |
936 | rwbs[i++] = 'A'; | |
937 | if (t->action & BLK_TC_BARRIER) | |
938 | rwbs[i++] = 'B'; | |
939 | if (t->action & BLK_TC_SYNC) | |
940 | rwbs[i++] = 'S'; | |
941 | if (t->action & BLK_TC_META) | |
942 | rwbs[i++] = 'M'; | |
943 | ||
944 | rwbs[i] = '\0'; | |
c71a8961 ACM |
945 | } |
946 | ||
947 | static inline | |
948 | const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent) | |
949 | { | |
950 | return (const struct blk_io_trace *)ent; | |
951 | } | |
952 | ||
953 | static inline const void *pdu_start(const struct trace_entry *ent) | |
954 | { | |
955 | return te_blk_io_trace(ent) + 1; | |
956 | } | |
957 | ||
958 | static inline u32 t_sec(const struct trace_entry *ent) | |
959 | { | |
960 | return te_blk_io_trace(ent)->bytes >> 9; | |
961 | } | |
962 | ||
963 | static inline unsigned long long t_sector(const struct trace_entry *ent) | |
964 | { | |
965 | return te_blk_io_trace(ent)->sector; | |
966 | } | |
967 | ||
968 | static inline __u16 t_error(const struct trace_entry *ent) | |
969 | { | |
970 | return te_blk_io_trace(ent)->sector; | |
971 | } | |
972 | ||
973 | static __u64 get_pdu_int(const struct trace_entry *ent) | |
974 | { | |
975 | const __u64 *val = pdu_start(ent); | |
976 | return be64_to_cpu(*val); | |
977 | } | |
978 | ||
979 | static void get_pdu_remap(const struct trace_entry *ent, | |
980 | struct blk_io_trace_remap *r) | |
981 | { | |
982 | const struct blk_io_trace_remap *__r = pdu_start(ent); | |
983 | __u64 sector = __r->sector; | |
984 | ||
985 | r->device = be32_to_cpu(__r->device); | |
986 | r->device_from = be32_to_cpu(__r->device_from); | |
987 | r->sector = be64_to_cpu(sector); | |
988 | } | |
989 | ||
990 | static int blk_log_action_iter(struct trace_iterator *iter, const char *act) | |
991 | { | |
992 | char rwbs[6]; | |
993 | unsigned long long ts = ns2usecs(iter->ts); | |
994 | unsigned long usec_rem = do_div(ts, USEC_PER_SEC); | |
995 | unsigned secs = (unsigned long)ts; | |
996 | const struct trace_entry *ent = iter->ent; | |
997 | const struct blk_io_trace *t = (const struct blk_io_trace *)ent; | |
998 | ||
999 | fill_rwbs(rwbs, t); | |
1000 | ||
1001 | return trace_seq_printf(&iter->seq, | |
1002 | "%3d,%-3d %2d %5d.%06lu %5u %2s %3s ", | |
1003 | MAJOR(t->device), MINOR(t->device), iter->cpu, | |
1004 | secs, usec_rem, ent->pid, act, rwbs); | |
1005 | } | |
1006 | ||
1007 | static int blk_log_action_seq(struct trace_seq *s, const struct blk_io_trace *t, | |
1008 | const char *act) | |
1009 | { | |
1010 | char rwbs[6]; | |
1011 | fill_rwbs(rwbs, t); | |
1012 | return trace_seq_printf(s, "%3d,%-3d %2s %3s ", | |
1013 | MAJOR(t->device), MINOR(t->device), act, rwbs); | |
1014 | } | |
1015 | ||
1016 | static int blk_log_generic(struct trace_seq *s, const struct trace_entry *ent) | |
1017 | { | |
4ca53085 SR |
1018 | char cmd[TASK_COMM_LEN]; |
1019 | ||
1020 | trace_find_cmdline(ent->pid, cmd); | |
c71a8961 ACM |
1021 | |
1022 | if (t_sec(ent)) | |
1023 | return trace_seq_printf(s, "%llu + %u [%s]\n", | |
1024 | t_sector(ent), t_sec(ent), cmd); | |
1025 | return trace_seq_printf(s, "[%s]\n", cmd); | |
1026 | } | |
1027 | ||
157f9c00 ACM |
1028 | static int blk_log_with_error(struct trace_seq *s, |
1029 | const struct trace_entry *ent) | |
c71a8961 ACM |
1030 | { |
1031 | if (t_sec(ent)) | |
1032 | return trace_seq_printf(s, "%llu + %u [%d]\n", t_sector(ent), | |
1033 | t_sec(ent), t_error(ent)); | |
1034 | return trace_seq_printf(s, "%llu [%d]\n", t_sector(ent), t_error(ent)); | |
1035 | } | |
1036 | ||
1037 | static int blk_log_remap(struct trace_seq *s, const struct trace_entry *ent) | |
1038 | { | |
1039 | struct blk_io_trace_remap r = { .device = 0, }; | |
1040 | ||
1041 | get_pdu_remap(ent, &r); | |
1042 | return trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n", | |
1043 | t_sector(ent), | |
1044 | t_sec(ent), MAJOR(r.device), MINOR(r.device), | |
1045 | (unsigned long long)r.sector); | |
1046 | } | |
1047 | ||
1048 | static int blk_log_plug(struct trace_seq *s, const struct trace_entry *ent) | |
1049 | { | |
4ca53085 SR |
1050 | char cmd[TASK_COMM_LEN]; |
1051 | ||
1052 | trace_find_cmdline(ent->pid, cmd); | |
1053 | ||
1054 | return trace_seq_printf(s, "[%s]\n", cmd); | |
c71a8961 ACM |
1055 | } |
1056 | ||
1057 | static int blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent) | |
1058 | { | |
4ca53085 SR |
1059 | char cmd[TASK_COMM_LEN]; |
1060 | ||
1061 | trace_find_cmdline(ent->pid, cmd); | |
1062 | ||
1063 | return trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent)); | |
c71a8961 ACM |
1064 | } |
1065 | ||
1066 | static int blk_log_split(struct trace_seq *s, const struct trace_entry *ent) | |
1067 | { | |
4ca53085 SR |
1068 | char cmd[TASK_COMM_LEN]; |
1069 | ||
1070 | trace_find_cmdline(ent->pid, cmd); | |
1071 | ||
c71a8961 | 1072 | return trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent), |
4ca53085 | 1073 | get_pdu_int(ent), cmd); |
c71a8961 ACM |
1074 | } |
1075 | ||
1076 | /* | |
1077 | * struct tracer operations | |
1078 | */ | |
1079 | ||
1080 | static void blk_tracer_print_header(struct seq_file *m) | |
1081 | { | |
1082 | if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC)) | |
1083 | return; | |
1084 | seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n" | |
1085 | "# | | | | | |\n"); | |
1086 | } | |
1087 | ||
1088 | static void blk_tracer_start(struct trace_array *tr) | |
1089 | { | |
c71a8961 | 1090 | if (atomic_add_return(1, &blk_probes_ref) == 1) |
3c289ba7 | 1091 | blk_register_tracepoints(); |
08a06b83 | 1092 | trace_flags &= ~TRACE_ITER_CONTEXT_INFO; |
c71a8961 ACM |
1093 | } |
1094 | ||
1095 | static int blk_tracer_init(struct trace_array *tr) | |
1096 | { | |
1097 | blk_tr = tr; | |
1098 | blk_tracer_start(tr); | |
5006ea73 | 1099 | blk_tracer_enabled = true; |
c71a8961 ACM |
1100 | return 0; |
1101 | } | |
1102 | ||
1103 | static void blk_tracer_stop(struct trace_array *tr) | |
1104 | { | |
08a06b83 | 1105 | trace_flags |= TRACE_ITER_CONTEXT_INFO; |
c71a8961 ACM |
1106 | if (atomic_dec_and_test(&blk_probes_ref)) |
1107 | blk_unregister_tracepoints(); | |
c71a8961 ACM |
1108 | } |
1109 | ||
1110 | static void blk_tracer_reset(struct trace_array *tr) | |
1111 | { | |
1112 | if (!atomic_read(&blk_probes_ref)) | |
1113 | return; | |
1114 | ||
5006ea73 | 1115 | blk_tracer_enabled = false; |
c71a8961 ACM |
1116 | blk_tracer_stop(tr); |
1117 | } | |
1118 | ||
1119 | static struct { | |
1120 | const char *act[2]; | |
ef18012b | 1121 | int (*print)(struct trace_seq *s, const struct trace_entry *ent); |
c71a8961 | 1122 | } what2act[] __read_mostly = { |
ef18012b | 1123 | [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic }, |
c71a8961 ACM |
1124 | [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic }, |
1125 | [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic }, | |
1126 | [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic }, | |
1127 | [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic }, | |
1128 | [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error }, | |
1129 | [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic }, | |
1130 | [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error }, | |
1131 | [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug }, | |
1132 | [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug }, | |
1133 | [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug }, | |
1134 | [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic }, | |
1135 | [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split }, | |
1136 | [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic }, | |
1137 | [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap }, | |
1138 | }; | |
1139 | ||
ae7462b4 ACM |
1140 | static enum print_line_t blk_trace_event_print(struct trace_iterator *iter, |
1141 | int flags) | |
c71a8961 | 1142 | { |
2c9b238e ACM |
1143 | struct trace_seq *s = &iter->seq; |
1144 | const struct blk_io_trace *t = (struct blk_io_trace *)iter->ent; | |
c71a8961 ACM |
1145 | const u16 what = t->action & ((1 << BLK_TC_SHIFT) - 1); |
1146 | int ret; | |
1147 | ||
d9793bd8 | 1148 | if (!trace_print_context(iter)) |
08a06b83 ACM |
1149 | return TRACE_TYPE_PARTIAL_LINE; |
1150 | ||
c71a8961 ACM |
1151 | if (unlikely(what == 0 || what > ARRAY_SIZE(what2act))) |
1152 | ret = trace_seq_printf(s, "Bad pc action %x\n", what); | |
1153 | else { | |
1154 | const bool long_act = !!(trace_flags & TRACE_ITER_VERBOSE); | |
1155 | ret = blk_log_action_seq(s, t, what2act[what].act[long_act]); | |
1156 | if (ret) | |
2c9b238e | 1157 | ret = what2act[what].print(s, iter->ent); |
c71a8961 ACM |
1158 | } |
1159 | ||
1160 | return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE; | |
1161 | } | |
1162 | ||
08a06b83 ACM |
1163 | static int blk_trace_synthesize_old_trace(struct trace_iterator *iter) |
1164 | { | |
1165 | struct trace_seq *s = &iter->seq; | |
1166 | struct blk_io_trace *t = (struct blk_io_trace *)iter->ent; | |
1167 | const int offset = offsetof(struct blk_io_trace, sector); | |
1168 | struct blk_io_trace old = { | |
1169 | .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION, | |
1170 | .time = ns2usecs(iter->ts), | |
1171 | }; | |
1172 | ||
1173 | if (!trace_seq_putmem(s, &old, offset)) | |
1174 | return 0; | |
1175 | return trace_seq_putmem(s, &t->sector, | |
1176 | sizeof(old) - offset + t->pdu_len); | |
1177 | } | |
1178 | ||
ae7462b4 ACM |
1179 | static enum print_line_t |
1180 | blk_trace_event_print_binary(struct trace_iterator *iter, int flags) | |
08a06b83 ACM |
1181 | { |
1182 | return blk_trace_synthesize_old_trace(iter) ? | |
1183 | TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE; | |
1184 | } | |
1185 | ||
c71a8961 ACM |
1186 | static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter) |
1187 | { | |
1188 | const struct blk_io_trace *t; | |
1189 | u16 what; | |
1190 | int ret; | |
1191 | ||
1192 | if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC)) | |
1193 | return TRACE_TYPE_UNHANDLED; | |
1194 | ||
1195 | t = (const struct blk_io_trace *)iter->ent; | |
1196 | what = t->action & ((1 << BLK_TC_SHIFT) - 1); | |
1197 | ||
1198 | if (unlikely(what == 0 || what > ARRAY_SIZE(what2act))) | |
1199 | ret = trace_seq_printf(&iter->seq, "Bad pc action %x\n", what); | |
1200 | else { | |
1201 | const bool long_act = !!(trace_flags & TRACE_ITER_VERBOSE); | |
1202 | ret = blk_log_action_iter(iter, what2act[what].act[long_act]); | |
1203 | if (ret) | |
1204 | ret = what2act[what].print(&iter->seq, iter->ent); | |
1205 | } | |
1206 | ||
1207 | return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE; | |
1208 | } | |
1209 | ||
1210 | static struct tracer blk_tracer __read_mostly = { | |
1211 | .name = "blk", | |
1212 | .init = blk_tracer_init, | |
1213 | .reset = blk_tracer_reset, | |
1214 | .start = blk_tracer_start, | |
1215 | .stop = blk_tracer_stop, | |
1216 | .print_header = blk_tracer_print_header, | |
1217 | .print_line = blk_tracer_print_line, | |
1218 | .flags = &blk_tracer_flags, | |
1219 | }; | |
1220 | ||
1221 | static struct trace_event trace_blk_event = { | |
ef18012b | 1222 | .type = TRACE_BLK, |
c71a8961 | 1223 | .trace = blk_trace_event_print, |
08a06b83 | 1224 | .binary = blk_trace_event_print_binary, |
c71a8961 ACM |
1225 | }; |
1226 | ||
1227 | static int __init init_blk_tracer(void) | |
1228 | { | |
1229 | if (!register_ftrace_event(&trace_blk_event)) { | |
1230 | pr_warning("Warning: could not register block events\n"); | |
1231 | return 1; | |
1232 | } | |
1233 | ||
1234 | if (register_tracer(&blk_tracer) != 0) { | |
1235 | pr_warning("Warning: could not register the block tracer\n"); | |
1236 | unregister_ftrace_event(&trace_blk_event); | |
1237 | return 1; | |
1238 | } | |
1239 | ||
1240 | return 0; | |
1241 | } | |
1242 | ||
1243 | device_initcall(init_blk_tracer); | |
1244 | ||
1245 | static int blk_trace_remove_queue(struct request_queue *q) | |
1246 | { | |
1247 | struct blk_trace *bt; | |
1248 | ||
1249 | bt = xchg(&q->blk_trace, NULL); | |
1250 | if (bt == NULL) | |
1251 | return -EINVAL; | |
1252 | ||
1253 | kfree(bt); | |
1254 | return 0; | |
1255 | } | |
1256 | ||
1257 | /* | |
1258 | * Setup everything required to start tracing | |
1259 | */ | |
1260 | static int blk_trace_setup_queue(struct request_queue *q, dev_t dev) | |
1261 | { | |
1262 | struct blk_trace *old_bt, *bt = NULL; | |
1263 | int ret; | |
1264 | ||
1265 | ret = -ENOMEM; | |
1266 | bt = kzalloc(sizeof(*bt), GFP_KERNEL); | |
1267 | if (!bt) | |
1268 | goto err; | |
1269 | ||
1270 | bt->dev = dev; | |
1271 | bt->act_mask = (u16)-1; | |
1272 | bt->end_lba = -1ULL; | |
1273 | bt->trace_state = Blktrace_running; | |
1274 | ||
1275 | old_bt = xchg(&q->blk_trace, bt); | |
1276 | if (old_bt != NULL) { | |
1277 | (void)xchg(&q->blk_trace, old_bt); | |
1278 | kfree(bt); | |
1279 | ret = -EBUSY; | |
1280 | } | |
1281 | return 0; | |
1282 | err: | |
1283 | return ret; | |
1284 | } | |
1285 | ||
1286 | /* | |
1287 | * sysfs interface to enable and configure tracing | |
1288 | */ | |
1289 | ||
1290 | static ssize_t sysfs_blk_trace_enable_show(struct device *dev, | |
1291 | struct device_attribute *attr, | |
1292 | char *buf) | |
1293 | { | |
1294 | struct hd_struct *p = dev_to_part(dev); | |
1295 | struct block_device *bdev; | |
1296 | ssize_t ret = -ENXIO; | |
1297 | ||
1298 | lock_kernel(); | |
1299 | bdev = bdget(part_devt(p)); | |
1300 | if (bdev != NULL) { | |
1301 | struct request_queue *q = bdev_get_queue(bdev); | |
1302 | ||
1303 | if (q != NULL) { | |
1304 | mutex_lock(&bdev->bd_mutex); | |
1305 | ret = sprintf(buf, "%u\n", !!q->blk_trace); | |
1306 | mutex_unlock(&bdev->bd_mutex); | |
1307 | } | |
1308 | ||
1309 | bdput(bdev); | |
1310 | } | |
1311 | ||
1312 | unlock_kernel(); | |
1313 | return ret; | |
1314 | } | |
1315 | ||
1316 | static ssize_t sysfs_blk_trace_enable_store(struct device *dev, | |
1317 | struct device_attribute *attr, | |
1318 | const char *buf, size_t count) | |
1319 | { | |
1320 | struct block_device *bdev; | |
1321 | struct request_queue *q; | |
1322 | struct hd_struct *p; | |
1323 | int value; | |
1324 | ssize_t ret = -ENXIO; | |
1325 | ||
1326 | if (count == 0 || sscanf(buf, "%d", &value) != 1) | |
1327 | goto out; | |
1328 | ||
1329 | lock_kernel(); | |
1330 | p = dev_to_part(dev); | |
1331 | bdev = bdget(part_devt(p)); | |
1332 | if (bdev == NULL) | |
1333 | goto out_unlock_kernel; | |
1334 | ||
1335 | q = bdev_get_queue(bdev); | |
1336 | if (q == NULL) | |
1337 | goto out_bdput; | |
1338 | ||
1339 | mutex_lock(&bdev->bd_mutex); | |
1340 | if (value) | |
1341 | ret = blk_trace_setup_queue(q, bdev->bd_dev); | |
1342 | else | |
1343 | ret = blk_trace_remove_queue(q); | |
1344 | mutex_unlock(&bdev->bd_mutex); | |
1345 | ||
1346 | if (ret == 0) | |
1347 | ret = count; | |
1348 | out_bdput: | |
1349 | bdput(bdev); | |
1350 | out_unlock_kernel: | |
1351 | unlock_kernel(); | |
1352 | out: | |
1353 | return ret; | |
1354 | } | |
1355 | ||
1356 | static ssize_t sysfs_blk_trace_attr_show(struct device *dev, | |
1357 | struct device_attribute *attr, | |
1358 | char *buf); | |
1359 | static ssize_t sysfs_blk_trace_attr_store(struct device *dev, | |
1360 | struct device_attribute *attr, | |
1361 | const char *buf, size_t count); | |
1362 | #define BLK_TRACE_DEVICE_ATTR(_name) \ | |
1363 | DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \ | |
1364 | sysfs_blk_trace_attr_show, \ | |
1365 | sysfs_blk_trace_attr_store) | |
1366 | ||
1367 | static DEVICE_ATTR(enable, S_IRUGO | S_IWUSR, | |
1368 | sysfs_blk_trace_enable_show, sysfs_blk_trace_enable_store); | |
1369 | static BLK_TRACE_DEVICE_ATTR(act_mask); | |
1370 | static BLK_TRACE_DEVICE_ATTR(pid); | |
1371 | static BLK_TRACE_DEVICE_ATTR(start_lba); | |
1372 | static BLK_TRACE_DEVICE_ATTR(end_lba); | |
1373 | ||
1374 | static struct attribute *blk_trace_attrs[] = { | |
1375 | &dev_attr_enable.attr, | |
1376 | &dev_attr_act_mask.attr, | |
1377 | &dev_attr_pid.attr, | |
1378 | &dev_attr_start_lba.attr, | |
1379 | &dev_attr_end_lba.attr, | |
1380 | NULL | |
1381 | }; | |
1382 | ||
1383 | struct attribute_group blk_trace_attr_group = { | |
1384 | .name = "trace", | |
1385 | .attrs = blk_trace_attrs, | |
1386 | }; | |
1387 | ||
1388 | static int blk_str2act_mask(const char *str) | |
1389 | { | |
1390 | int mask = 0; | |
1391 | char *copy = kstrdup(str, GFP_KERNEL), *s; | |
1392 | ||
1393 | if (copy == NULL) | |
1394 | return -ENOMEM; | |
1395 | ||
1396 | s = strstrip(copy); | |
1397 | ||
1398 | while (1) { | |
1399 | char *sep = strchr(s, ','); | |
1400 | ||
1401 | if (sep != NULL) | |
1402 | *sep = '\0'; | |
1403 | ||
1404 | if (strcasecmp(s, "barrier") == 0) | |
1405 | mask |= BLK_TC_BARRIER; | |
1406 | else if (strcasecmp(s, "complete") == 0) | |
1407 | mask |= BLK_TC_COMPLETE; | |
1408 | else if (strcasecmp(s, "fs") == 0) | |
1409 | mask |= BLK_TC_FS; | |
1410 | else if (strcasecmp(s, "issue") == 0) | |
1411 | mask |= BLK_TC_ISSUE; | |
1412 | else if (strcasecmp(s, "pc") == 0) | |
1413 | mask |= BLK_TC_PC; | |
1414 | else if (strcasecmp(s, "queue") == 0) | |
1415 | mask |= BLK_TC_QUEUE; | |
1416 | else if (strcasecmp(s, "read") == 0) | |
1417 | mask |= BLK_TC_READ; | |
1418 | else if (strcasecmp(s, "requeue") == 0) | |
1419 | mask |= BLK_TC_REQUEUE; | |
1420 | else if (strcasecmp(s, "sync") == 0) | |
1421 | mask |= BLK_TC_SYNC; | |
1422 | else if (strcasecmp(s, "write") == 0) | |
1423 | mask |= BLK_TC_WRITE; | |
1424 | ||
1425 | if (sep == NULL) | |
1426 | break; | |
1427 | ||
1428 | s = sep + 1; | |
1429 | } | |
1430 | kfree(copy); | |
1431 | ||
1432 | return mask; | |
1433 | } | |
1434 | ||
1435 | static ssize_t sysfs_blk_trace_attr_show(struct device *dev, | |
1436 | struct device_attribute *attr, | |
1437 | char *buf) | |
1438 | { | |
1439 | struct hd_struct *p = dev_to_part(dev); | |
1440 | struct request_queue *q; | |
1441 | struct block_device *bdev; | |
1442 | ssize_t ret = -ENXIO; | |
1443 | ||
1444 | lock_kernel(); | |
1445 | bdev = bdget(part_devt(p)); | |
1446 | if (bdev == NULL) | |
1447 | goto out_unlock_kernel; | |
1448 | ||
1449 | q = bdev_get_queue(bdev); | |
1450 | if (q == NULL) | |
1451 | goto out_bdput; | |
1452 | mutex_lock(&bdev->bd_mutex); | |
1453 | if (q->blk_trace == NULL) | |
1454 | ret = sprintf(buf, "disabled\n"); | |
1455 | else if (attr == &dev_attr_act_mask) | |
1456 | ret = sprintf(buf, "%#x\n", q->blk_trace->act_mask); | |
1457 | else if (attr == &dev_attr_pid) | |
1458 | ret = sprintf(buf, "%u\n", q->blk_trace->pid); | |
1459 | else if (attr == &dev_attr_start_lba) | |
1460 | ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba); | |
1461 | else if (attr == &dev_attr_end_lba) | |
1462 | ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba); | |
1463 | mutex_unlock(&bdev->bd_mutex); | |
1464 | out_bdput: | |
1465 | bdput(bdev); | |
1466 | out_unlock_kernel: | |
1467 | unlock_kernel(); | |
1468 | return ret; | |
1469 | } | |
1470 | ||
1471 | static ssize_t sysfs_blk_trace_attr_store(struct device *dev, | |
1472 | struct device_attribute *attr, | |
1473 | const char *buf, size_t count) | |
1474 | { | |
1475 | struct block_device *bdev; | |
1476 | struct request_queue *q; | |
1477 | struct hd_struct *p; | |
1478 | u64 value; | |
1479 | ssize_t ret = -ENXIO; | |
1480 | ||
1481 | if (count == 0) | |
1482 | goto out; | |
1483 | ||
1484 | if (attr == &dev_attr_act_mask) { | |
1485 | if (sscanf(buf, "%llx", &value) != 1) { | |
1486 | /* Assume it is a list of trace category names */ | |
1487 | value = blk_str2act_mask(buf); | |
1488 | if (value < 0) | |
1489 | goto out; | |
1490 | } | |
1491 | } else if (sscanf(buf, "%llu", &value) != 1) | |
1492 | goto out; | |
1493 | ||
1494 | lock_kernel(); | |
1495 | p = dev_to_part(dev); | |
1496 | bdev = bdget(part_devt(p)); | |
1497 | if (bdev == NULL) | |
1498 | goto out_unlock_kernel; | |
1499 | ||
1500 | q = bdev_get_queue(bdev); | |
1501 | if (q == NULL) | |
1502 | goto out_bdput; | |
1503 | ||
1504 | mutex_lock(&bdev->bd_mutex); | |
1505 | ret = 0; | |
1506 | if (q->blk_trace == NULL) | |
1507 | ret = blk_trace_setup_queue(q, bdev->bd_dev); | |
1508 | ||
1509 | if (ret == 0) { | |
1510 | if (attr == &dev_attr_act_mask) | |
1511 | q->blk_trace->act_mask = value; | |
1512 | else if (attr == &dev_attr_pid) | |
1513 | q->blk_trace->pid = value; | |
1514 | else if (attr == &dev_attr_start_lba) | |
1515 | q->blk_trace->start_lba = value; | |
1516 | else if (attr == &dev_attr_end_lba) | |
1517 | q->blk_trace->end_lba = value; | |
1518 | ret = count; | |
1519 | } | |
1520 | mutex_unlock(&bdev->bd_mutex); | |
1521 | out_bdput: | |
1522 | bdput(bdev); | |
1523 | out_unlock_kernel: | |
1524 | unlock_kernel(); | |
1525 | out: | |
1526 | return ret; | |
1527 | } |