1	// SPDX-License-Identifier: GPL-2.0
2	/*
3	* Copyright (C) 2006 Jens Axboe <axboe@kernel.dk>
4	*
5	*/
6
7	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
8
9	#include <linux/kernel.h>
10	#include <linux/blkdev.h>
11	#include <linux/blktrace_api.h>
12	#include <linux/percpu.h>
13	#include <linux/init.h>
14	#include <linux/mutex.h>
15	#include <linux/slab.h>
16	#include <linux/debugfs.h>
17	#include <linux/export.h>
18	#include <linux/time.h>
19	#include <linux/uaccess.h>
20	#include <linux/list.h>
21	#include <linux/blk-cgroup.h>
22
23	#include "../../block/blk.h"
24
25	#include <trace/events/block.h>
26
27	#include "trace_output.h"
28
29	#ifdef CONFIG_BLK_DEV_IO_TRACE
30
31	static unsigned int blktrace_seq __read_mostly = 1;
32
33	static struct trace_array *blk_tr;
34	static bool blk_tracer_enabled __read_mostly;
35
36	static LIST_HEAD(running_trace_list);
37	static __cacheline_aligned_in_smp DEFINE_RAW_SPINLOCK(running_trace_lock);
38
39	/* Select an alternative, minimalistic output than the original one */
40	#define TRACE_BLK_OPT_CLASSIC 0x1
41	#define TRACE_BLK_OPT_CGROUP 0x2
42	#define TRACE_BLK_OPT_CGNAME 0x4
43
44	static struct tracer_opt blk_tracer_opts[] = {
45	/* Default disable the minimalistic output */
46	{ TRACER_OPT(blk_classic, TRACE_BLK_OPT_CLASSIC) },
47	#ifdef CONFIG_BLK_CGROUP
48	{ TRACER_OPT(blk_cgroup, TRACE_BLK_OPT_CGROUP) },
49	{ TRACER_OPT(blk_cgname, TRACE_BLK_OPT_CGNAME) },
50	#endif
51	{ }
52	};
53
54	static struct tracer_flags blk_tracer_flags = {
55	.val = 0,
56	.opts = blk_tracer_opts,
57	};
58
59	/* Global reference count of probes */
60	static DEFINE_MUTEX(blk_probe_mutex);
61	static int blk_probes_ref;
62
63	static void blk_register_tracepoints(void);
64	static void blk_unregister_tracepoints(void);
65
66	/*
67	* Send out a notify message.
68	*/
69	static void trace_note(struct blk_trace *bt, pid_t pid, int action,
70	const void *data, size_t len, u64 cgid)
71	{
72	struct blk_io_trace *t;
73	struct ring_buffer_event *event = NULL;
74	struct trace_buffer *buffer = NULL;
75	unsigned int trace_ctx = 0;
76	int cpu = smp_processor_id();
77	bool blk_tracer = blk_tracer_enabled;
78	ssize_t cgid_len = cgid ? sizeof(cgid) : 0;
79
80	if (blk_tracer) {
81	buffer = blk_tr->array_buffer.buffer;
82	trace_ctx = tracing_gen_ctx_flags(irqflags: 0);
83	event = trace_buffer_lock_reserve(buffer, type: TRACE_BLK,
84	len: sizeof(*t) + len + cgid_len,
85	trace_ctx);
86	if (!event)
87	return;
88	t = ring_buffer_event_data(event);
89	goto record_it;
90	}
91
92	if (!bt->rchan)
93	return;
94
95	t = relay_reserve(chan: bt->rchan, length: sizeof(*t) + len + cgid_len);
96	if (t) {
97	t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
98	t->time = ktime_to_ns(kt: ktime_get());
99	record_it:
100	t->device = bt->dev;
101	t->action = action | (cgid ? __BLK_TN_CGROUP : 0);
102	t->pid = pid;
103	t->cpu = cpu;
104	t->pdu_len = len + cgid_len;
105	if (cgid_len)
106	memcpy((void *)t + sizeof(*t), &cgid, cgid_len);
107	memcpy((void *) t + sizeof(*t) + cgid_len, data, len);
108
109	if (blk_tracer)
110	trace_buffer_unlock_commit(tr: blk_tr, buffer, event, trace_ctx);
111	}
112	}
113
114	/*
115	* Send out a notify for this process, if we haven't done so since a trace
116	* started
117	*/
118	static void trace_note_tsk(struct task_struct *tsk)
119	{
120	unsigned long flags;
121	struct blk_trace *bt;
122
123	tsk->btrace_seq = blktrace_seq;
124	raw_spin_lock_irqsave(&running_trace_lock, flags);
125	list_for_each_entry(bt, &running_trace_list, running_list) {
126	trace_note(bt, pid: tsk->pid, BLK_TN_PROCESS, data: tsk->comm,
127	len: sizeof(tsk->comm), cgid: 0);
128	}
129	raw_spin_unlock_irqrestore(&running_trace_lock, flags);
130	}
131
132	static void trace_note_time(struct blk_trace *bt)
133	{
134	struct timespec64 now;
135	unsigned long flags;
136	u32 words[2];
137
138	/* need to check user space to see if this breaks in y2038 or y2106 */
139	ktime_get_real_ts64(tv: &now);
140	words[0] = (u32)now.tv_sec;
141	words[1] = now.tv_nsec;
142
143	local_irq_save(flags);
144	trace_note(bt, pid: 0, BLK_TN_TIMESTAMP, data: words, len: sizeof(words), cgid: 0);
145	local_irq_restore(flags);
146	}
147
148	void __blk_trace_note_message(struct blk_trace *bt,
149	struct cgroup_subsys_state *css, const char *fmt, ...)
150	{
151	int n;
152	va_list args;
153	unsigned long flags;
154	char *buf;
155	u64 cgid = 0;
156
157	if (unlikely(bt->trace_state != Blktrace_running &&
158	!blk_tracer_enabled))
159	return;
160
161	/*
162	* If the BLK_TC_NOTIFY action mask isn't set, don't send any note
163	* message to the trace.
164	*/
165	if (!(bt->act_mask & BLK_TC_NOTIFY))
166	return;
167
168	local_irq_save(flags);
169	buf = this_cpu_ptr(bt->msg_data);
170	va_start(args, fmt);
171	n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args);
172	va_end(args);
173
174	#ifdef CONFIG_BLK_CGROUP
175	if (css && (blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP))
176	cgid = cgroup_id(cgrp: css->cgroup);
177	else
178	cgid = 1;
179	#endif
180	trace_note(bt, current->pid, BLK_TN_MESSAGE, data: buf, len: n, cgid);
181	local_irq_restore(flags);
182	}
183	EXPORT_SYMBOL_GPL(__blk_trace_note_message);
184
185	static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
186	pid_t pid)
187	{
188	if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0)
189	return 1;
190	if (sector && (sector < bt->start_lba || sector > bt->end_lba))
191	return 1;
192	if (bt->pid && pid != bt->pid)
193	return 1;
194
195	return 0;
196	}
197
198	/*
199	* Data direction bit lookup
200	*/
201	static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ),
202	BLK_TC_ACT(BLK_TC_WRITE) };
203
204	#define BLK_TC_RAHEAD BLK_TC_AHEAD
205	#define BLK_TC_PREFLUSH BLK_TC_FLUSH
206
207	/* The ilog2() calls fall out because they're constant */
208	#define MASK_TC_BIT(rw, __name) ((__force u32)(rw & REQ_ ## __name) << \
209	(ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - __REQ_ ## __name))
210
211	/*
212	* The worker for the various blk_add_trace*() types. Fills out a
213	* blk_io_trace structure and places it in a per-cpu subbuffer.
214	*/
215	static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
216	const blk_opf_t opf, u32 what, int error,
217	int pdu_len, void *pdu_data, u64 cgid)
218	{
219	struct task_struct *tsk = current;
220	struct ring_buffer_event *event = NULL;
221	struct trace_buffer *buffer = NULL;
222	struct blk_io_trace *t;
223	unsigned long flags = 0;
224	unsigned long *sequence;
225	unsigned int trace_ctx = 0;
226	pid_t pid;
227	int cpu;
228	bool blk_tracer = blk_tracer_enabled;
229	ssize_t cgid_len = cgid ? sizeof(cgid) : 0;
230	const enum req_op op = opf & REQ_OP_MASK;
231
232	if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer))
233	return;
234
235	what |= ddir_act[op_is_write(op) ? WRITE : READ];
236	what |= MASK_TC_BIT(opf, SYNC);
237	what |= MASK_TC_BIT(opf, RAHEAD);
238	what |= MASK_TC_BIT(opf, META);
239	what |= MASK_TC_BIT(opf, PREFLUSH);
240	what |= MASK_TC_BIT(opf, FUA);
241	if (op == REQ_OP_DISCARD || op == REQ_OP_SECURE_ERASE)
242	what |= BLK_TC_ACT(BLK_TC_DISCARD);
243	if (op == REQ_OP_FLUSH)
244	what |= BLK_TC_ACT(BLK_TC_FLUSH);
245	if (cgid)
246	what |= __BLK_TA_CGROUP;
247
248	pid = tsk->pid;
249	if (act_log_check(bt, what, sector, pid))
250	return;
251	cpu = raw_smp_processor_id();
252
253	if (blk_tracer) {
254	tracing_record_cmdline(current);
255
256	buffer = blk_tr->array_buffer.buffer;
257	trace_ctx = tracing_gen_ctx_flags(irqflags: 0);
258	event = trace_buffer_lock_reserve(buffer, type: TRACE_BLK,
259	len: sizeof(*t) + pdu_len + cgid_len,
260	trace_ctx);
261	if (!event)
262	return;
263	t = ring_buffer_event_data(event);
264	goto record_it;
265	}
266
267	if (unlikely(tsk->btrace_seq != blktrace_seq))
268	trace_note_tsk(tsk);
269
270	/*
271	* A word about the locking here - we disable interrupts to reserve
272	* some space in the relay per-cpu buffer, to prevent an irq
273	* from coming in and stepping on our toes.
274	*/
275	local_irq_save(flags);
276	t = relay_reserve(chan: bt->rchan, length: sizeof(*t) + pdu_len + cgid_len);
277	if (t) {
278	sequence = per_cpu_ptr(bt->sequence, cpu);
279
280	t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
281	t->sequence = ++(*sequence);
282	t->time = ktime_to_ns(kt: ktime_get());
283	record_it:
284	/*
285	* These two are not needed in ftrace as they are in the
286	* generic trace_entry, filled by tracing_generic_entry_update,
287	* but for the trace_event->bin() synthesizer benefit we do it
288	* here too.
289	*/
290	t->cpu = cpu;
291	t->pid = pid;
292
293	t->sector = sector;
294	t->bytes = bytes;
295	t->action = what;
296	t->device = bt->dev;
297	t->error = error;
298	t->pdu_len = pdu_len + cgid_len;
299
300	if (cgid_len)
301	memcpy((void *)t + sizeof(*t), &cgid, cgid_len);
302	if (pdu_len)
303	memcpy((void *)t + sizeof(*t) + cgid_len, pdu_data, pdu_len);
304
305	if (blk_tracer) {
306	trace_buffer_unlock_commit(tr: blk_tr, buffer, event, trace_ctx);
307	return;
308	}
309	}
310
311	local_irq_restore(flags);
312	}
313
314	static void blk_trace_free(struct request_queue *q, struct blk_trace *bt)
315	{
316	relay_close(chan: bt->rchan);
317
318	/*
319	* If 'bt->dir' is not set, then both 'dropped' and 'msg' are created
320	* under 'q->debugfs_dir', thus lookup and remove them.
321	*/
322	if (!bt->dir) {
323	debugfs_lookup_and_remove(name: "dropped", parent: q->debugfs_dir);
324	debugfs_lookup_and_remove(name: "msg", parent: q->debugfs_dir);
325	} else {
326	debugfs_remove(dentry: bt->dir);
327	}
328	free_percpu(pdata: bt->sequence);
329	free_percpu(pdata: bt->msg_data);
330	kfree(objp: bt);
331	}
332
333	static void get_probe_ref(void)
334	{
335	mutex_lock(&blk_probe_mutex);
336	if (++blk_probes_ref == 1)
337	blk_register_tracepoints();
338	mutex_unlock(lock: &blk_probe_mutex);
339	}
340
341	static void put_probe_ref(void)
342	{
343	mutex_lock(&blk_probe_mutex);
344	if (!--blk_probes_ref)
345	blk_unregister_tracepoints();
346	mutex_unlock(lock: &blk_probe_mutex);
347	}
348
349	static int blk_trace_start(struct blk_trace *bt)
350	{
351	if (bt->trace_state != Blktrace_setup &&
352	bt->trace_state != Blktrace_stopped)
353	return -EINVAL;
354
355	blktrace_seq++;
356	smp_mb();
357	bt->trace_state = Blktrace_running;
358	raw_spin_lock_irq(&running_trace_lock);
359	list_add(new: &bt->running_list, head: &running_trace_list);
360	raw_spin_unlock_irq(&running_trace_lock);
361	trace_note_time(bt);
362
363	return 0;
364	}
365
366	static int blk_trace_stop(struct blk_trace *bt)
367	{
368	if (bt->trace_state != Blktrace_running)
369	return -EINVAL;
370
371	bt->trace_state = Blktrace_stopped;
372	raw_spin_lock_irq(&running_trace_lock);
373	list_del_init(entry: &bt->running_list);
374	raw_spin_unlock_irq(&running_trace_lock);
375	relay_flush(chan: bt->rchan);
376
377	return 0;
378	}
379
380	static void blk_trace_cleanup(struct request_queue *q, struct blk_trace *bt)
381	{
382	blk_trace_stop(bt);
383	synchronize_rcu();
384	blk_trace_free(q, bt);
385	put_probe_ref();
386	}
387
388	static int __blk_trace_remove(struct request_queue *q)
389	{
390	struct blk_trace *bt;
391
392	bt = rcu_replace_pointer(q->blk_trace, NULL,
393	lockdep_is_held(&q->debugfs_mutex));
394	if (!bt)
395	return -EINVAL;
396
397	blk_trace_cleanup(q, bt);
398
399	return 0;
400	}
401
402	int blk_trace_remove(struct request_queue *q)
403	{
404	int ret;
405
406	mutex_lock(&q->debugfs_mutex);
407	ret = __blk_trace_remove(q);
408	mutex_unlock(lock: &q->debugfs_mutex);
409
410	return ret;
411	}
412	EXPORT_SYMBOL_GPL(blk_trace_remove);
413
414	static ssize_t blk_dropped_read(struct file *filp, char __user *buffer,
415	size_t count, loff_t *ppos)
416	{
417	struct blk_trace *bt = filp->private_data;
418	char buf[16];
419
420	snprintf(buf, size: sizeof(buf), fmt: "%u\n", atomic_read(v: &bt->dropped));
421
422	return simple_read_from_buffer(to: buffer, count, ppos, from: buf, strlen(buf));
423	}
424
425	static const struct file_operations blk_dropped_fops = {
426	.owner = THIS_MODULE,
427	.open = simple_open,
428	.read = blk_dropped_read,
429	.llseek = default_llseek,
430	};
431
432	static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
433	size_t count, loff_t *ppos)
434	{
435	char *msg;
436	struct blk_trace *bt;
437
438	if (count >= BLK_TN_MAX_MSG)
439	return -EINVAL;
440
441	msg = memdup_user_nul(buffer, count);
442	if (IS_ERR(ptr: msg))
443	return PTR_ERR(ptr: msg);
444
445	bt = filp->private_data;
446	__blk_trace_note_message(bt, NULL, "%s", msg);
447	kfree(objp: msg);
448
449	return count;
450	}
451
452	static const struct file_operations blk_msg_fops = {
453	.owner = THIS_MODULE,
454	.open = simple_open,
455	.write = blk_msg_write,
456	.llseek = noop_llseek,
457	};
458
459	/*
460	* Keep track of how many times we encountered a full subbuffer, to aid
461	* the user space app in telling how many lost events there were.
462	*/
463	static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
464	void *prev_subbuf, size_t prev_padding)
465	{
466	struct blk_trace *bt;
467
468	if (!relay_buf_full(buf))
469	return 1;
470
471	bt = buf->chan->private_data;
472	atomic_inc(v: &bt->dropped);
473	return 0;
474	}
475
476	static int blk_remove_buf_file_callback(struct dentry *dentry)
477	{
478	debugfs_remove(dentry);
479
480	return 0;
481	}
482
483	static struct dentry *blk_create_buf_file_callback(const char *filename,
484	struct dentry *parent,
485	umode_t mode,
486	struct rchan_buf *buf,
487	int *is_global)
488	{
489	return debugfs_create_file(filename, mode, parent, buf,
490	&relay_file_operations);
491	}
492
493	static const struct rchan_callbacks blk_relay_callbacks = {
494	.subbuf_start = blk_subbuf_start_callback,
495	.create_buf_file = blk_create_buf_file_callback,
496	.remove_buf_file = blk_remove_buf_file_callback,
497	};
498
499	static void blk_trace_setup_lba(struct blk_trace *bt,
500	struct block_device *bdev)
501	{
502	if (bdev) {
503	bt->start_lba = bdev->bd_start_sect;
504	bt->end_lba = bdev->bd_start_sect + bdev_nr_sectors(bdev);
505	} else {
506	bt->start_lba = 0;
507	bt->end_lba = -1ULL;
508	}
509	}
510
511	/*
512	* Setup everything required to start tracing
513	*/
514	static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
515	struct block_device *bdev,
516	struct blk_user_trace_setup *buts)
517	{
518	struct blk_trace *bt = NULL;
519	struct dentry *dir = NULL;
520	int ret;
521
522	lockdep_assert_held(&q->debugfs_mutex);
523
524	if (!buts->buf_size || !buts->buf_nr)
525	return -EINVAL;
526
527	strscpy_pad(buts->name, name, BLKTRACE_BDEV_SIZE);
528
529	/*
530	* some device names have larger paths - convert the slashes
531	* to underscores for this to work as expected
532	*/
533	strreplace(str: buts->name, old: '/', new: '_');
534
535	/*
536	* bdev can be NULL, as with scsi-generic, this is a helpful as
537	* we can be.
538	*/
539	if (rcu_dereference_protected(q->blk_trace,
540	lockdep_is_held(&q->debugfs_mutex))) {
541	pr_warn("Concurrent blktraces are not allowed on %s\n",
542	buts->name);
543	return -EBUSY;
544	}
545
546	bt = kzalloc(sizeof(*bt), GFP_KERNEL);
547	if (!bt)
548	return -ENOMEM;
549
550	ret = -ENOMEM;
551	bt->sequence = alloc_percpu(unsigned long);
552	if (!bt->sequence)
553	goto err;
554
555	bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
556	if (!bt->msg_data)
557	goto err;
558
559	/*
560	* When tracing the whole disk reuse the existing debugfs directory
561	* created by the block layer on init. For partitions block devices,
562	* and scsi-generic block devices we create a temporary new debugfs
563	* directory that will be removed once the trace ends.
564	*/
565	if (bdev && !bdev_is_partition(bdev))
566	dir = q->debugfs_dir;
567	else
568	bt->dir = dir = debugfs_create_dir(name: buts->name, parent: blk_debugfs_root);
569
570	/*
571	* As blktrace relies on debugfs for its interface the debugfs directory
572	* is required, contrary to the usual mantra of not checking for debugfs
573	* files or directories.
574	*/
575	if (IS_ERR_OR_NULL(ptr: dir)) {
576	pr_warn("debugfs_dir not present for %s so skipping\n",
577	buts->name);
578	ret = -ENOENT;
579	goto err;
580	}
581
582	bt->dev = dev;
583	atomic_set(v: &bt->dropped, i: 0);
584	INIT_LIST_HEAD(list: &bt->running_list);
585
586	ret = -EIO;
587	debugfs_create_file("dropped", 0444, dir, bt, &blk_dropped_fops);
588	debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
589
590	bt->rchan = relay_open(base_filename: "trace", parent: dir, subbuf_size: buts->buf_size,
591	n_subbufs: buts->buf_nr, cb: &blk_relay_callbacks, private_data: bt);
592	if (!bt->rchan)
593	goto err;
594
595	bt->act_mask = buts->act_mask;
596	if (!bt->act_mask)
597	bt->act_mask = (u16) -1;
598
599	blk_trace_setup_lba(bt, bdev);
600
601	/* overwrite with user settings */
602	if (buts->start_lba)
603	bt->start_lba = buts->start_lba;
604	if (buts->end_lba)
605	bt->end_lba = buts->end_lba;
606
607	bt->pid = buts->pid;
608	bt->trace_state = Blktrace_setup;
609
610	rcu_assign_pointer(q->blk_trace, bt);
611	get_probe_ref();
612
613	ret = 0;
614	err:
615	if (ret)
616	blk_trace_free(q, bt);
617	return ret;
618	}
619
620	int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
621	struct block_device *bdev,
622	char __user *arg)
623	{
624	struct blk_user_trace_setup buts;
625	int ret;
626
627	ret = copy_from_user(to: &buts, from: arg, n: sizeof(buts));
628	if (ret)
629	return -EFAULT;
630
631	mutex_lock(&q->debugfs_mutex);
632	ret = do_blk_trace_setup(q, name, dev, bdev, buts: &buts);
633	mutex_unlock(lock: &q->debugfs_mutex);
634	if (ret)
635	return ret;
636
637	if (copy_to_user(to: arg, from: &buts, n: sizeof(buts))) {
638	blk_trace_remove(q);
639	return -EFAULT;
640	}
641	return 0;
642	}
643	EXPORT_SYMBOL_GPL(blk_trace_setup);
644
645	#if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
646	static int compat_blk_trace_setup(struct request_queue *q, char *name,
647	dev_t dev, struct block_device *bdev,
648	char __user *arg)
649	{
650	struct blk_user_trace_setup buts;
651	struct compat_blk_user_trace_setup cbuts;
652	int ret;
653
654	if (copy_from_user(to: &cbuts, from: arg, n: sizeof(cbuts)))
655	return -EFAULT;
656
657	buts = (struct blk_user_trace_setup) {
658	.act_mask = cbuts.act_mask,
659	.buf_size = cbuts.buf_size,
660	.buf_nr = cbuts.buf_nr,
661	.start_lba = cbuts.start_lba,
662	.end_lba = cbuts.end_lba,
663	.pid = cbuts.pid,
664	};
665
666	mutex_lock(&q->debugfs_mutex);
667	ret = do_blk_trace_setup(q, name, dev, bdev, buts: &buts);
668	mutex_unlock(lock: &q->debugfs_mutex);
669	if (ret)
670	return ret;
671
672	if (copy_to_user(to: arg, from: &buts.name, ARRAY_SIZE(buts.name))) {
673	blk_trace_remove(q);
674	return -EFAULT;
675	}
676
677	return 0;
678	}
679	#endif
680
681	static int __blk_trace_startstop(struct request_queue *q, int start)
682	{
683	struct blk_trace *bt;
684
685	bt = rcu_dereference_protected(q->blk_trace,
686	lockdep_is_held(&q->debugfs_mutex));
687	if (bt == NULL)
688	return -EINVAL;
689
690	if (start)
691	return blk_trace_start(bt);
692	else
693	return blk_trace_stop(bt);
694	}
695
696	int blk_trace_startstop(struct request_queue *q, int start)
697	{
698	int ret;
699
700	mutex_lock(&q->debugfs_mutex);
701	ret = __blk_trace_startstop(q, start);
702	mutex_unlock(lock: &q->debugfs_mutex);
703
704	return ret;
705	}
706	EXPORT_SYMBOL_GPL(blk_trace_startstop);
707
708	/*
709	* When reading or writing the blktrace sysfs files, the references to the
710	* opened sysfs or device files should prevent the underlying block device
711	* from being removed. So no further delete protection is really needed.
712	*/
713
714	/**
715	* blk_trace_ioctl - handle the ioctls associated with tracing
716	* @bdev: the block device
717	* @cmd: the ioctl cmd
718	* @arg: the argument data, if any
719	*
720	**/
721	int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
722	{
723	struct request_queue *q = bdev_get_queue(bdev);
724	int ret, start = 0;
725	char b[BDEVNAME_SIZE];
726
727	switch (cmd) {
728	case BLKTRACESETUP:
729	snprintf(buf: b, size: sizeof(b), fmt: "%pg", bdev);
730	ret = blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
731	break;
732	#if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
733	case BLKTRACESETUP32:
734	snprintf(buf: b, size: sizeof(b), fmt: "%pg", bdev);
735	ret = compat_blk_trace_setup(q, name: b, dev: bdev->bd_dev, bdev, arg);
736	break;
737	#endif
738	case BLKTRACESTART:
739	start = 1;
740	fallthrough;
741	case BLKTRACESTOP:
742	ret = blk_trace_startstop(q, start);
743	break;
744	case BLKTRACETEARDOWN:
745	ret = blk_trace_remove(q);
746	break;
747	default:
748	ret = -ENOTTY;
749	break;
750	}
751	return ret;
752	}
753
754	/**
755	* blk_trace_shutdown - stop and cleanup trace structures
756	* @q: the request queue associated with the device
757	*
758	**/
759	void blk_trace_shutdown(struct request_queue *q)
760	{
761	if (rcu_dereference_protected(q->blk_trace,
762	lockdep_is_held(&q->debugfs_mutex)))
763	__blk_trace_remove(q);
764	}
765
766	#ifdef CONFIG_BLK_CGROUP
767	static u64 blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio)
768	{
769	struct cgroup_subsys_state *blkcg_css;
770	struct blk_trace *bt;
771
772	/* We don't use the 'bt' value here except as an optimization... */
773	bt = rcu_dereference_protected(q->blk_trace, 1);
774	if (!bt || !(blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP))
775	return 0;
776
777	blkcg_css = bio_blkcg_css(bio);
778	if (!blkcg_css)
779	return 0;
780	return cgroup_id(cgrp: blkcg_css->cgroup);
781	}
782	#else
783	static u64 blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio)
784	{
785	return 0;
786	}
787	#endif
788
789	static u64
790	blk_trace_request_get_cgid(struct request *rq)
791	{
792	if (!rq->bio)
793	return 0;
794	/* Use the first bio */
795	return blk_trace_bio_get_cgid(q: rq->q, bio: rq->bio);
796	}
797
798	/*
799	* blktrace probes
800	*/
801
802	/**
803	* blk_add_trace_rq - Add a trace for a request oriented action
804	* @rq: the source request
805	* @error: return status to log
806	* @nr_bytes: number of completed bytes
807	* @what: the action
808	* @cgid: the cgroup info
809	*
810	* Description:
811	* Records an action against a request. Will log the bio offset + size.
812	*
813	**/
814	static void blk_add_trace_rq(struct request *rq, blk_status_t error,
815	unsigned int nr_bytes, u32 what, u64 cgid)
816	{
817	struct blk_trace *bt;
818
819	rcu_read_lock();
820	bt = rcu_dereference(rq->q->blk_trace);
821	if (likely(!bt)) {
822	rcu_read_unlock();
823	return;
824	}
825
826	if (blk_rq_is_passthrough(rq))
827	what |= BLK_TC_ACT(BLK_TC_PC);
828	else
829	what |= BLK_TC_ACT(BLK_TC_FS);
830
831	__blk_add_trace(bt, sector: blk_rq_trace_sector(rq), bytes: nr_bytes, opf: rq->cmd_flags,
832	what, error: blk_status_to_errno(status: error), pdu_len: 0, NULL, cgid);
833	rcu_read_unlock();
834	}
835
836	static void blk_add_trace_rq_insert(void *ignore, struct request *rq)
837	{
838	blk_add_trace_rq(rq, error: 0, nr_bytes: blk_rq_bytes(rq), BLK_TA_INSERT,
839	cgid: blk_trace_request_get_cgid(rq));
840	}
841
842	static void blk_add_trace_rq_issue(void *ignore, struct request *rq)
843	{
844	blk_add_trace_rq(rq, error: 0, nr_bytes: blk_rq_bytes(rq), BLK_TA_ISSUE,
845	cgid: blk_trace_request_get_cgid(rq));
846	}
847
848	static void blk_add_trace_rq_merge(void *ignore, struct request *rq)
849	{
850	blk_add_trace_rq(rq, error: 0, nr_bytes: blk_rq_bytes(rq), BLK_TA_BACKMERGE,
851	cgid: blk_trace_request_get_cgid(rq));
852	}
853
854	static void blk_add_trace_rq_requeue(void *ignore, struct request *rq)
855	{
856	blk_add_trace_rq(rq, error: 0, nr_bytes: blk_rq_bytes(rq), BLK_TA_REQUEUE,
857	cgid: blk_trace_request_get_cgid(rq));
858	}
859
860	static void blk_add_trace_rq_complete(void *ignore, struct request *rq,
861	blk_status_t error, unsigned int nr_bytes)
862	{
863	blk_add_trace_rq(rq, error, nr_bytes, BLK_TA_COMPLETE,
864	cgid: blk_trace_request_get_cgid(rq));
865	}
866
867	/**
868	* blk_add_trace_bio - Add a trace for a bio oriented action
869	* @q: queue the io is for
870	* @bio: the source bio
871	* @what: the action
872	* @error: error, if any
873	*
874	* Description:
875	* Records an action against a bio. Will log the bio offset + size.
876	*
877	**/
878	static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
879	u32 what, int error)
880	{
881	struct blk_trace *bt;
882
883	rcu_read_lock();
884	bt = rcu_dereference(q->blk_trace);
885	if (likely(!bt)) {
886	rcu_read_unlock();
887	return;
888	}
889
890	__blk_add_trace(bt, sector: bio->bi_iter.bi_sector, bytes: bio->bi_iter.bi_size,
891	opf: bio->bi_opf, what, error, pdu_len: 0, NULL,
892	cgid: blk_trace_bio_get_cgid(q, bio));
893	rcu_read_unlock();
894	}
895
896	static void blk_add_trace_bio_complete(void *ignore,
897	struct request_queue *q, struct bio *bio)
898	{
899	blk_add_trace_bio(q, bio, BLK_TA_COMPLETE,
900	error: blk_status_to_errno(status: bio->bi_status));
901	}
902
903	static void blk_add_trace_bio_backmerge(void *ignore, struct bio *bio)
904	{
905	blk_add_trace_bio(q: bio->bi_bdev->bd_disk->queue, bio, BLK_TA_BACKMERGE,
906	error: 0);
907	}
908
909	static void blk_add_trace_bio_frontmerge(void *ignore, struct bio *bio)
910	{
911	blk_add_trace_bio(q: bio->bi_bdev->bd_disk->queue, bio, BLK_TA_FRONTMERGE,
912	error: 0);
913	}
914
915	static void blk_add_trace_bio_queue(void *ignore, struct bio *bio)
916	{
917	blk_add_trace_bio(q: bio->bi_bdev->bd_disk->queue, bio, BLK_TA_QUEUE, error: 0);
918	}
919
920	static void blk_add_trace_getrq(void *ignore, struct bio *bio)
921	{
922	blk_add_trace_bio(q: bio->bi_bdev->bd_disk->queue, bio, BLK_TA_GETRQ, error: 0);
923	}
924
925	static void blk_add_trace_plug(void *ignore, struct request_queue *q)
926	{
927	struct blk_trace *bt;
928
929	rcu_read_lock();
930	bt = rcu_dereference(q->blk_trace);
931	if (bt)
932	__blk_add_trace(bt, sector: 0, bytes: 0, opf: 0, BLK_TA_PLUG, error: 0, pdu_len: 0, NULL, cgid: 0);
933	rcu_read_unlock();
934	}
935
936	static void blk_add_trace_unplug(void *ignore, struct request_queue *q,
937	unsigned int depth, bool explicit)
938	{
939	struct blk_trace *bt;
940
941	rcu_read_lock();
942	bt = rcu_dereference(q->blk_trace);
943	if (bt) {
944	__be64 rpdu = cpu_to_be64(depth);
945	u32 what;
946
947	if (explicit)
948	what = BLK_TA_UNPLUG_IO;
949	else
950	what = BLK_TA_UNPLUG_TIMER;
951
952	__blk_add_trace(bt, sector: 0, bytes: 0, opf: 0, what, error: 0, pdu_len: sizeof(rpdu), pdu_data: &rpdu, cgid: 0);
953	}
954	rcu_read_unlock();
955	}
956
957	static void blk_add_trace_split(void *ignore, struct bio *bio, unsigned int pdu)
958	{
959	struct request_queue *q = bio->bi_bdev->bd_disk->queue;
960	struct blk_trace *bt;
961
962	rcu_read_lock();
963	bt = rcu_dereference(q->blk_trace);
964	if (bt) {
965	__be64 rpdu = cpu_to_be64(pdu);
966
967	__blk_add_trace(bt, sector: bio->bi_iter.bi_sector,
968	bytes: bio->bi_iter.bi_size, opf: bio->bi_opf, BLK_TA_SPLIT,
969	error: blk_status_to_errno(status: bio->bi_status),
970	pdu_len: sizeof(rpdu), pdu_data: &rpdu,
971	cgid: blk_trace_bio_get_cgid(q, bio));
972	}
973	rcu_read_unlock();
974	}
975
976	/**
977	* blk_add_trace_bio_remap - Add a trace for a bio-remap operation
978	* @ignore: trace callback data parameter (not used)
979	* @bio: the source bio
980	* @dev: source device
981	* @from: source sector
982	*
983	* Called after a bio is remapped to a different device and/or sector.
984	**/
985	static void blk_add_trace_bio_remap(void *ignore, struct bio *bio, dev_t dev,
986	sector_t from)
987	{
988	struct request_queue *q = bio->bi_bdev->bd_disk->queue;
989	struct blk_trace *bt;
990	struct blk_io_trace_remap r;
991
992	rcu_read_lock();
993	bt = rcu_dereference(q->blk_trace);
994	if (likely(!bt)) {
995	rcu_read_unlock();
996	return;
997	}
998
999	r.device_from = cpu_to_be32(dev);
1000	r.device_to = cpu_to_be32(bio_dev(bio));
1001	r.sector_from = cpu_to_be64(from);
1002
1003	__blk_add_trace(bt, sector: bio->bi_iter.bi_sector, bytes: bio->bi_iter.bi_size,
1004	opf: bio->bi_opf, BLK_TA_REMAP,
1005	error: blk_status_to_errno(status: bio->bi_status),
1006	pdu_len: sizeof(r), pdu_data: &r, cgid: blk_trace_bio_get_cgid(q, bio));
1007	rcu_read_unlock();
1008	}
1009
1010	/**
1011	* blk_add_trace_rq_remap - Add a trace for a request-remap operation
1012	* @ignore: trace callback data parameter (not used)
1013	* @rq: the source request
1014	* @dev: target device
1015	* @from: source sector
1016	*
1017	* Description:
1018	* Device mapper remaps request to other devices.
1019	* Add a trace for that action.
1020	*
1021	**/
1022	static void blk_add_trace_rq_remap(void *ignore, struct request *rq, dev_t dev,
1023	sector_t from)
1024	{
1025	struct blk_trace *bt;
1026	struct blk_io_trace_remap r;
1027
1028	rcu_read_lock();
1029	bt = rcu_dereference(rq->q->blk_trace);
1030	if (likely(!bt)) {
1031	rcu_read_unlock();
1032	return;
1033	}
1034
1035	r.device_from = cpu_to_be32(dev);
1036	r.device_to = cpu_to_be32(disk_devt(rq->q->disk));
1037	r.sector_from = cpu_to_be64(from);
1038
1039	__blk_add_trace(bt, sector: blk_rq_pos(rq), bytes: blk_rq_bytes(rq),
1040	opf: rq->cmd_flags, BLK_TA_REMAP, error: 0,
1041	pdu_len: sizeof(r), pdu_data: &r, cgid: blk_trace_request_get_cgid(rq));
1042	rcu_read_unlock();
1043	}
1044
1045	/**
1046	* blk_add_driver_data - Add binary message with driver-specific data
1047	* @rq: io request
1048	* @data: driver-specific data
1049	* @len: length of driver-specific data
1050	*
1051	* Description:
1052	* Some drivers might want to write driver-specific data per request.
1053	*
1054	**/
1055	void blk_add_driver_data(struct request *rq, void *data, size_t len)
1056	{
1057	struct blk_trace *bt;
1058
1059	rcu_read_lock();
1060	bt = rcu_dereference(rq->q->blk_trace);
1061	if (likely(!bt)) {
1062	rcu_read_unlock();
1063	return;
1064	}
1065
1066	__blk_add_trace(bt, sector: blk_rq_trace_sector(rq), bytes: blk_rq_bytes(rq), opf: 0,
1067	BLK_TA_DRV_DATA, error: 0, pdu_len: len, pdu_data: data,
1068	cgid: blk_trace_request_get_cgid(rq));
1069	rcu_read_unlock();
1070	}
1071	EXPORT_SYMBOL_GPL(blk_add_driver_data);
1072
1073	static void blk_register_tracepoints(void)
1074	{
1075	int ret;
1076
1077	ret = register_trace_block_rq_insert(probe: blk_add_trace_rq_insert, NULL);
1078	WARN_ON(ret);
1079	ret = register_trace_block_rq_issue(probe: blk_add_trace_rq_issue, NULL);
1080	WARN_ON(ret);
1081	ret = register_trace_block_rq_merge(probe: blk_add_trace_rq_merge, NULL);
1082	WARN_ON(ret);
1083	ret = register_trace_block_rq_requeue(probe: blk_add_trace_rq_requeue, NULL);
1084	WARN_ON(ret);
1085	ret = register_trace_block_rq_complete(probe: blk_add_trace_rq_complete, NULL);
1086	WARN_ON(ret);
1087	ret = register_trace_block_bio_complete(probe: blk_add_trace_bio_complete, NULL);
1088	WARN_ON(ret);
1089	ret = register_trace_block_bio_backmerge(probe: blk_add_trace_bio_backmerge, NULL);
1090	WARN_ON(ret);
1091	ret = register_trace_block_bio_frontmerge(probe: blk_add_trace_bio_frontmerge, NULL);
1092	WARN_ON(ret);
1093	ret = register_trace_block_bio_queue(probe: blk_add_trace_bio_queue, NULL);
1094	WARN_ON(ret);
1095	ret = register_trace_block_getrq(probe: blk_add_trace_getrq, NULL);
1096	WARN_ON(ret);
1097	ret = register_trace_block_plug(probe: blk_add_trace_plug, NULL);
1098	WARN_ON(ret);
1099	ret = register_trace_block_unplug(probe: blk_add_trace_unplug, NULL);
1100	WARN_ON(ret);
1101	ret = register_trace_block_split(probe: blk_add_trace_split, NULL);
1102	WARN_ON(ret);
1103	ret = register_trace_block_bio_remap(probe: blk_add_trace_bio_remap, NULL);
1104	WARN_ON(ret);
1105	ret = register_trace_block_rq_remap(probe: blk_add_trace_rq_remap, NULL);
1106	WARN_ON(ret);
1107	}
1108
1109	static void blk_unregister_tracepoints(void)
1110	{
1111	unregister_trace_block_rq_remap(probe: blk_add_trace_rq_remap, NULL);
1112	unregister_trace_block_bio_remap(probe: blk_add_trace_bio_remap, NULL);
1113	unregister_trace_block_split(probe: blk_add_trace_split, NULL);
1114	unregister_trace_block_unplug(probe: blk_add_trace_unplug, NULL);
1115	unregister_trace_block_plug(probe: blk_add_trace_plug, NULL);
1116	unregister_trace_block_getrq(probe: blk_add_trace_getrq, NULL);
1117	unregister_trace_block_bio_queue(probe: blk_add_trace_bio_queue, NULL);
1118	unregister_trace_block_bio_frontmerge(probe: blk_add_trace_bio_frontmerge, NULL);
1119	unregister_trace_block_bio_backmerge(probe: blk_add_trace_bio_backmerge, NULL);
1120	unregister_trace_block_bio_complete(probe: blk_add_trace_bio_complete, NULL);
1121	unregister_trace_block_rq_complete(probe: blk_add_trace_rq_complete, NULL);
1122	unregister_trace_block_rq_requeue(probe: blk_add_trace_rq_requeue, NULL);
1123	unregister_trace_block_rq_merge(probe: blk_add_trace_rq_merge, NULL);
1124	unregister_trace_block_rq_issue(probe: blk_add_trace_rq_issue, NULL);
1125	unregister_trace_block_rq_insert(probe: blk_add_trace_rq_insert, NULL);
1126
1127	tracepoint_synchronize_unregister();
1128	}
1129
1130	/*
1131	* struct blk_io_tracer formatting routines
1132	*/
1133
1134	static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
1135	{
1136	int i = 0;
1137	int tc = t->action >> BLK_TC_SHIFT;
1138
1139	if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) {
1140	rwbs[i++] = 'N';
1141	goto out;
1142	}
1143
1144	if (tc & BLK_TC_FLUSH)
1145	rwbs[i++] = 'F';
1146
1147	if (tc & BLK_TC_DISCARD)
1148	rwbs[i++] = 'D';
1149	else if (tc & BLK_TC_WRITE)
1150	rwbs[i++] = 'W';
1151	else if (t->bytes)
1152	rwbs[i++] = 'R';
1153	else
1154	rwbs[i++] = 'N';
1155
1156	if (tc & BLK_TC_FUA)
1157	rwbs[i++] = 'F';
1158	if (tc & BLK_TC_AHEAD)
1159	rwbs[i++] = 'A';
1160	if (tc & BLK_TC_SYNC)
1161	rwbs[i++] = 'S';
1162	if (tc & BLK_TC_META)
1163	rwbs[i++] = 'M';
1164	out:
1165	rwbs[i] = '\0';
1166	}
1167
1168	static inline
1169	const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent)
1170	{
1171	return (const struct blk_io_trace *)ent;
1172	}
1173
1174	static inline const void *pdu_start(const struct trace_entry *ent, bool has_cg)
1175	{
1176	return (void *)(te_blk_io_trace(ent) + 1) + (has_cg ? sizeof(u64) : 0);
1177	}
1178
1179	static inline u64 t_cgid(const struct trace_entry *ent)
1180	{
1181	return *(u64 *)(te_blk_io_trace(ent) + 1);
1182	}
1183
1184	static inline int pdu_real_len(const struct trace_entry *ent, bool has_cg)
1185	{
1186	return te_blk_io_trace(ent)->pdu_len - (has_cg ? sizeof(u64) : 0);
1187	}
1188
1189	static inline u32 t_action(const struct trace_entry *ent)
1190	{
1191	return te_blk_io_trace(ent)->action;
1192	}
1193
1194	static inline u32 t_bytes(const struct trace_entry *ent)
1195	{
1196	return te_blk_io_trace(ent)->bytes;
1197	}
1198
1199	static inline u32 t_sec(const struct trace_entry *ent)
1200	{
1201	return te_blk_io_trace(ent)->bytes >> 9;
1202	}
1203
1204	static inline unsigned long long t_sector(const struct trace_entry *ent)
1205	{
1206	return te_blk_io_trace(ent)->sector;
1207	}
1208
1209	static inline __u16 t_error(const struct trace_entry *ent)
1210	{
1211	return te_blk_io_trace(ent)->error;
1212	}
1213
1214	static __u64 get_pdu_int(const struct trace_entry *ent, bool has_cg)
1215	{
1216	const __be64 *val = pdu_start(ent, has_cg);
1217	return be64_to_cpu(*val);
1218	}
1219
1220	typedef void (blk_log_action_t) (struct trace_iterator *iter, const char *act,
1221	bool has_cg);
1222
1223	static void blk_log_action_classic(struct trace_iterator *iter, const char *act,
1224	bool has_cg)
1225	{
1226	char rwbs[RWBS_LEN];
1227	unsigned long long ts = iter->ts;
1228	unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC);
1229	unsigned secs = (unsigned long)ts;
1230	const struct blk_io_trace *t = te_blk_io_trace(ent: iter->ent);
1231
1232	fill_rwbs(rwbs, t);
1233
1234	trace_seq_printf(s: &iter->seq,
1235	fmt: "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
1236	MAJOR(t->device), MINOR(t->device), iter->cpu,
1237	secs, nsec_rem, iter->ent->pid, act, rwbs);
1238	}
1239
1240	static void blk_log_action(struct trace_iterator *iter, const char *act,
1241	bool has_cg)
1242	{
1243	char rwbs[RWBS_LEN];
1244	const struct blk_io_trace *t = te_blk_io_trace(ent: iter->ent);
1245
1246	fill_rwbs(rwbs, t);
1247	if (has_cg) {
1248	u64 id = t_cgid(ent: iter->ent);
1249
1250	if (blk_tracer_flags.val & TRACE_BLK_OPT_CGNAME) {
1251	char blkcg_name_buf[NAME_MAX + 1] = "<...>";
1252
1253	cgroup_path_from_kernfs_id(id, buf: blkcg_name_buf,
1254	buflen: sizeof(blkcg_name_buf));
1255	trace_seq_printf(s: &iter->seq, fmt: "%3d,%-3d %s %2s %3s ",
1256	MAJOR(t->device), MINOR(t->device),
1257	blkcg_name_buf, act, rwbs);
1258	} else {
1259	/*
1260	* The cgid portion used to be "INO,GEN". Userland
1261	* builds a FILEID_INO32_GEN fid out of them and
1262	* opens the cgroup using open_by_handle_at(2).
1263	* While 32bit ino setups are still the same, 64bit
1264	* ones now use the 64bit ino as the whole ID and
1265	* no longer use generation.
1266	*
1267	* Regardless of the content, always output
1268	* "LOW32,HIGH32" so that FILEID_INO32_GEN fid can
1269	* be mapped back to @id on both 64 and 32bit ino
1270	* setups. See __kernfs_fh_to_dentry().
1271	*/
1272	trace_seq_printf(s: &iter->seq,
1273	fmt: "%3d,%-3d %llx,%-llx %2s %3s ",
1274	MAJOR(t->device), MINOR(t->device),
1275	id & U32_MAX, id >> 32, act, rwbs);
1276	}
1277	} else
1278	trace_seq_printf(s: &iter->seq, fmt: "%3d,%-3d %2s %3s ",
1279	MAJOR(t->device), MINOR(t->device), act, rwbs);
1280	}
1281
1282	static void blk_log_dump_pdu(struct trace_seq *s,
1283	const struct trace_entry *ent, bool has_cg)
1284	{
1285	const unsigned char *pdu_buf;
1286	int pdu_len;
1287	int i, end;
1288
1289	pdu_buf = pdu_start(ent, has_cg);
1290	pdu_len = pdu_real_len(ent, has_cg);
1291
1292	if (!pdu_len)
1293	return;
1294
1295	/* find the last zero that needs to be printed */
1296	for (end = pdu_len - 1; end >= 0; end--)
1297	if (pdu_buf[end])
1298	break;
1299	end++;
1300
1301	trace_seq_putc(s, c: '(');
1302
1303	for (i = 0; i < pdu_len; i++) {
1304
1305	trace_seq_printf(s, fmt: "%s%02x",
1306	i == 0 ? "" : " ", pdu_buf[i]);
1307
1308	/*
1309	* stop when the rest is just zeros and indicate so
1310	* with a ".." appended
1311	*/
1312	if (i == end && end != pdu_len - 1) {
1313	trace_seq_puts(s, str: " ..) ");
1314	return;
1315	}
1316	}
1317
1318	trace_seq_puts(s, str: ") ");
1319	}
1320
1321	static void blk_log_generic(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1322	{
1323	char cmd[TASK_COMM_LEN];
1324
1325	trace_find_cmdline(pid: ent->pid, comm: cmd);
1326
1327	if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1328	trace_seq_printf(s, fmt: "%u ", t_bytes(ent));
1329	blk_log_dump_pdu(s, ent, has_cg);
1330	trace_seq_printf(s, fmt: "[%s]\n", cmd);
1331	} else {
1332	if (t_sec(ent))
1333	trace_seq_printf(s, fmt: "%llu + %u [%s]\n",
1334	t_sector(ent), t_sec(ent), cmd);
1335	else
1336	trace_seq_printf(s, fmt: "[%s]\n", cmd);
1337	}
1338	}
1339
1340	static void blk_log_with_error(struct trace_seq *s,
1341	const struct trace_entry *ent, bool has_cg)
1342	{
1343	if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1344	blk_log_dump_pdu(s, ent, has_cg);
1345	trace_seq_printf(s, fmt: "[%d]\n", t_error(ent));
1346	} else {
1347	if (t_sec(ent))
1348	trace_seq_printf(s, fmt: "%llu + %u [%d]\n",
1349	t_sector(ent),
1350	t_sec(ent), t_error(ent));
1351	else
1352	trace_seq_printf(s, fmt: "%llu [%d]\n",
1353	t_sector(ent), t_error(ent));
1354	}
1355	}
1356
1357	static void blk_log_remap(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1358	{
1359	const struct blk_io_trace_remap *__r = pdu_start(ent, has_cg);
1360
1361	trace_seq_printf(s, fmt: "%llu + %u <- (%d,%d) %llu\n",
1362	t_sector(ent), t_sec(ent),
1363	MAJOR(be32_to_cpu(__r->device_from)),
1364	MINOR(be32_to_cpu(__r->device_from)),
1365	be64_to_cpu(__r->sector_from));
1366	}
1367
1368	static void blk_log_plug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1369	{
1370	char cmd[TASK_COMM_LEN];
1371
1372	trace_find_cmdline(pid: ent->pid, comm: cmd);
1373
1374	trace_seq_printf(s, fmt: "[%s]\n", cmd);
1375	}
1376
1377	static void blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1378	{
1379	char cmd[TASK_COMM_LEN];
1380
1381	trace_find_cmdline(pid: ent->pid, comm: cmd);
1382
1383	trace_seq_printf(s, fmt: "[%s] %llu\n", cmd, get_pdu_int(ent, has_cg));
1384	}
1385
1386	static void blk_log_split(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1387	{
1388	char cmd[TASK_COMM_LEN];
1389
1390	trace_find_cmdline(pid: ent->pid, comm: cmd);
1391
1392	trace_seq_printf(s, fmt: "%llu / %llu [%s]\n", t_sector(ent),
1393	get_pdu_int(ent, has_cg), cmd);
1394	}
1395
1396	static void blk_log_msg(struct trace_seq *s, const struct trace_entry *ent,
1397	bool has_cg)
1398	{
1399
1400	trace_seq_putmem(s, mem: pdu_start(ent, has_cg),
1401	len: pdu_real_len(ent, has_cg));
1402	trace_seq_putc(s, c: '\n');
1403	}
1404
1405	/*
1406	* struct tracer operations
1407	*/
1408
1409	static void blk_tracer_print_header(struct seq_file *m)
1410	{
1411	if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1412	return;
1413	seq_puts(m, s: "# DEV CPU TIMESTAMP PID ACT FLG\n"
1414	"# | | | | | |\n");
1415	}
1416
1417	static void blk_tracer_start(struct trace_array *tr)
1418	{
1419	blk_tracer_enabled = true;
1420	}
1421
1422	static int blk_tracer_init(struct trace_array *tr)
1423	{
1424	blk_tr = tr;
1425	blk_tracer_start(tr);
1426	return 0;
1427	}
1428
1429	static void blk_tracer_stop(struct trace_array *tr)
1430	{
1431	blk_tracer_enabled = false;
1432	}
1433
1434	static void blk_tracer_reset(struct trace_array *tr)
1435	{
1436	blk_tracer_stop(tr);
1437	}
1438
1439	static const struct {
1440	const char *act[2];
1441	void (*print)(struct trace_seq *s, const struct trace_entry *ent,
1442	bool has_cg);
1443	} what2act[] = {
1444	[__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic },
1445	[__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic },
1446	[__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic },
1447	[__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic },
1448	[__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic },
1449	[__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error },
1450	[__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic },
1451	[__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error },
1452	[__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug },
1453	[__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug },
1454	[__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug },
1455	[__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic },
1456	[__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split },
1457	[__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap },
1458	};
1459
1460	static enum print_line_t print_one_line(struct trace_iterator *iter,
1461	bool classic)
1462	{
1463	struct trace_array *tr = iter->tr;
1464	struct trace_seq *s = &iter->seq;
1465	const struct blk_io_trace *t;
1466	u16 what;
1467	bool long_act;
1468	blk_log_action_t *log_action;
1469	bool has_cg;
1470
1471	t = te_blk_io_trace(ent: iter->ent);
1472	what = (t->action & ((1 << BLK_TC_SHIFT) - 1)) & ~__BLK_TA_CGROUP;
1473	long_act = !!(tr->trace_flags & TRACE_ITER_VERBOSE);
1474	log_action = classic ? &blk_log_action_classic : &blk_log_action;
1475	has_cg = t->action & __BLK_TA_CGROUP;
1476
1477	if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) {
1478	log_action(iter, long_act ? "message" : "m", has_cg);
1479	blk_log_msg(s, ent: iter->ent, has_cg);
1480	return trace_handle_return(s);
1481	}
1482
1483	if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
1484	trace_seq_printf(s, fmt: "Unknown action %x\n", what);
1485	else {
1486	log_action(iter, what2act[what].act[long_act], has_cg);
1487	what2act[what].print(s, iter->ent, has_cg);
1488	}
1489
1490	return trace_handle_return(s);
1491	}
1492
1493	static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
1494	int flags, struct trace_event *event)
1495	{
1496	return print_one_line(iter, classic: false);
1497	}
1498
1499	static void blk_trace_synthesize_old_trace(struct trace_iterator *iter)
1500	{
1501	struct trace_seq *s = &iter->seq;
1502	struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
1503	const int offset = offsetof(struct blk_io_trace, sector);
1504	struct blk_io_trace old = {
1505	.magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
1506	.time = iter->ts,
1507	};
1508
1509	trace_seq_putmem(s, mem: &old, len: offset);
1510	trace_seq_putmem(s, mem: &t->sector,
1511	len: sizeof(old) - offset + t->pdu_len);
1512	}
1513
1514	static enum print_line_t
1515	blk_trace_event_print_binary(struct trace_iterator *iter, int flags,
1516	struct trace_event *event)
1517	{
1518	blk_trace_synthesize_old_trace(iter);
1519
1520	return trace_handle_return(s: &iter->seq);
1521	}
1522
1523	static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
1524	{
1525	if ((iter->ent->type != TRACE_BLK) ||
1526	!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1527	return TRACE_TYPE_UNHANDLED;
1528
1529	return print_one_line(iter, classic: true);
1530	}
1531
1532	static int
1533	blk_tracer_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
1534	{
1535	/* don't output context-info for blk_classic output */
1536	if (bit == TRACE_BLK_OPT_CLASSIC) {
1537	if (set)
1538	tr->trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
1539	else
1540	tr->trace_flags |= TRACE_ITER_CONTEXT_INFO;
1541	}
1542	return 0;
1543	}
1544
1545	static struct tracer blk_tracer __read_mostly = {
1546	.name = "blk",
1547	.init = blk_tracer_init,
1548	.reset = blk_tracer_reset,
1549	.start = blk_tracer_start,
1550	.stop = blk_tracer_stop,
1551	.print_header = blk_tracer_print_header,
1552	.print_line = blk_tracer_print_line,
1553	.flags = &blk_tracer_flags,
1554	.set_flag = blk_tracer_set_flag,
1555	};
1556
1557	static struct trace_event_functions trace_blk_event_funcs = {
1558	.trace = blk_trace_event_print,
1559	.binary = blk_trace_event_print_binary,
1560	};
1561
1562	static struct trace_event trace_blk_event = {
1563	.type = TRACE_BLK,
1564	.funcs = &trace_blk_event_funcs,
1565	};
1566
1567	static int __init init_blk_tracer(void)
1568	{
1569	if (!register_trace_event(event: &trace_blk_event)) {
1570	pr_warn("Warning: could not register block events\n");
1571	return 1;
1572	}
1573
1574	if (register_tracer(type: &blk_tracer) != 0) {
1575	pr_warn("Warning: could not register the block tracer\n");
1576	unregister_trace_event(event: &trace_blk_event);
1577	return 1;
1578	}
1579
1580	return 0;
1581	}
1582
1583	device_initcall(init_blk_tracer);
1584
1585	static int blk_trace_remove_queue(struct request_queue *q)
1586	{
1587	struct blk_trace *bt;
1588
1589	bt = rcu_replace_pointer(q->blk_trace, NULL,
1590	lockdep_is_held(&q->debugfs_mutex));
1591	if (bt == NULL)
1592	return -EINVAL;
1593
1594	blk_trace_stop(bt);
1595
1596	put_probe_ref();
1597	synchronize_rcu();
1598	blk_trace_free(q, bt);
1599	return 0;
1600	}
1601
1602	/*
1603	* Setup everything required to start tracing
1604	*/
1605	static int blk_trace_setup_queue(struct request_queue *q,
1606	struct block_device *bdev)
1607	{
1608	struct blk_trace *bt = NULL;
1609	int ret = -ENOMEM;
1610
1611	bt = kzalloc(sizeof(*bt), GFP_KERNEL);
1612	if (!bt)
1613	return -ENOMEM;
1614
1615	bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
1616	if (!bt->msg_data)
1617	goto free_bt;
1618
1619	bt->dev = bdev->bd_dev;
1620	bt->act_mask = (u16)-1;
1621
1622	blk_trace_setup_lba(bt, bdev);
1623
1624	rcu_assign_pointer(q->blk_trace, bt);
1625	get_probe_ref();
1626	return 0;
1627
1628	free_bt:
1629	blk_trace_free(q, bt);
1630	return ret;
1631	}
1632
1633	/*
1634	* sysfs interface to enable and configure tracing
1635	*/
1636
1637	static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1638	struct device_attribute *attr,
1639	char *buf);
1640	static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1641	struct device_attribute *attr,
1642	const char *buf, size_t count);
1643	#define BLK_TRACE_DEVICE_ATTR(_name) \
1644	DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
1645	sysfs_blk_trace_attr_show, \
1646	sysfs_blk_trace_attr_store)
1647
1648	static BLK_TRACE_DEVICE_ATTR(enable);
1649	static BLK_TRACE_DEVICE_ATTR(act_mask);
1650	static BLK_TRACE_DEVICE_ATTR(pid);
1651	static BLK_TRACE_DEVICE_ATTR(start_lba);
1652	static BLK_TRACE_DEVICE_ATTR(end_lba);
1653
1654	static struct attribute *blk_trace_attrs[] = {
1655	&dev_attr_enable.attr,
1656	&dev_attr_act_mask.attr,
1657	&dev_attr_pid.attr,
1658	&dev_attr_start_lba.attr,
1659	&dev_attr_end_lba.attr,
1660	NULL
1661	};
1662
1663	struct attribute_group blk_trace_attr_group = {
1664	.name = "trace",
1665	.attrs = blk_trace_attrs,
1666	};
1667
1668	static const struct {
1669	int mask;
1670	const char *str;
1671	} mask_maps[] = {
1672	{ BLK_TC_READ, "read" },
1673	{ BLK_TC_WRITE, "write" },
1674	{ BLK_TC_FLUSH, "flush" },
1675	{ BLK_TC_SYNC, "sync" },
1676	{ BLK_TC_QUEUE, "queue" },
1677	{ BLK_TC_REQUEUE, "requeue" },
1678	{ BLK_TC_ISSUE, "issue" },
1679	{ BLK_TC_COMPLETE, "complete" },
1680	{ BLK_TC_FS, "fs" },
1681	{ BLK_TC_PC, "pc" },
1682	{ BLK_TC_NOTIFY, "notify" },
1683	{ BLK_TC_AHEAD, "ahead" },
1684	{ BLK_TC_META, "meta" },
1685	{ BLK_TC_DISCARD, "discard" },
1686	{ BLK_TC_DRV_DATA, "drv_data" },
1687	{ BLK_TC_FUA, "fua" },
1688	};
1689
1690	static int blk_trace_str2mask(const char *str)
1691	{
1692	int i;
1693	int mask = 0;
1694	char *buf, *s, *token;
1695
1696	buf = kstrdup(s: str, GFP_KERNEL);
1697	if (buf == NULL)
1698	return -ENOMEM;
1699	s = strstrip(str: buf);
1700
1701	while (1) {
1702	token = strsep(&s, ",");
1703	if (token == NULL)
1704	break;
1705
1706	if (*token == '\0')
1707	continue;
1708
1709	for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1710	if (strcasecmp(s1: token, s2: mask_maps[i].str) == 0) {
1711	mask |= mask_maps[i].mask;
1712	break;
1713	}
1714	}
1715	if (i == ARRAY_SIZE(mask_maps)) {
1716	mask = -EINVAL;
1717	break;
1718	}
1719	}
1720	kfree(objp: buf);
1721
1722	return mask;
1723	}
1724
1725	static ssize_t blk_trace_mask2str(char *buf, int mask)
1726	{
1727	int i;
1728	char *p = buf;
1729
1730	for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1731	if (mask & mask_maps[i].mask) {
1732	p += sprintf(buf: p, fmt: "%s%s",
1733	(p == buf) ? "" : ",", mask_maps[i].str);
1734	}
1735	}
1736	*p++ = '\n';
1737
1738	return p - buf;
1739	}
1740
1741	static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1742	struct device_attribute *attr,
1743	char *buf)
1744	{
1745	struct block_device *bdev = dev_to_bdev(dev);
1746	struct request_queue *q = bdev_get_queue(bdev);
1747	struct blk_trace *bt;
1748	ssize_t ret = -ENXIO;
1749
1750	mutex_lock(&q->debugfs_mutex);
1751
1752	bt = rcu_dereference_protected(q->blk_trace,
1753	lockdep_is_held(&q->debugfs_mutex));
1754	if (attr == &dev_attr_enable) {
1755	ret = sprintf(buf, fmt: "%u\n", !!bt);
1756	goto out_unlock_bdev;
1757	}
1758
1759	if (bt == NULL)
1760	ret = sprintf(buf, fmt: "disabled\n");
1761	else if (attr == &dev_attr_act_mask)
1762	ret = blk_trace_mask2str(buf, mask: bt->act_mask);
1763	else if (attr == &dev_attr_pid)
1764	ret = sprintf(buf, fmt: "%u\n", bt->pid);
1765	else if (attr == &dev_attr_start_lba)
1766	ret = sprintf(buf, fmt: "%llu\n", bt->start_lba);
1767	else if (attr == &dev_attr_end_lba)
1768	ret = sprintf(buf, fmt: "%llu\n", bt->end_lba);
1769
1770	out_unlock_bdev:
1771	mutex_unlock(lock: &q->debugfs_mutex);
1772	return ret;
1773	}
1774
1775	static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1776	struct device_attribute *attr,
1777	const char *buf, size_t count)
1778	{
1779	struct block_device *bdev = dev_to_bdev(dev);
1780	struct request_queue *q = bdev_get_queue(bdev);
1781	struct blk_trace *bt;
1782	u64 value;
1783	ssize_t ret = -EINVAL;
1784
1785	if (count == 0)
1786	goto out;
1787
1788	if (attr == &dev_attr_act_mask) {
1789	if (kstrtoull(s: buf, base: 0, res: &value)) {
1790	/* Assume it is a list of trace category names */
1791	ret = blk_trace_str2mask(str: buf);
1792	if (ret < 0)
1793	goto out;
1794	value = ret;
1795	}
1796	} else {
1797	if (kstrtoull(s: buf, base: 0, res: &value))
1798	goto out;
1799	}
1800
1801	mutex_lock(&q->debugfs_mutex);
1802
1803	bt = rcu_dereference_protected(q->blk_trace,
1804	lockdep_is_held(&q->debugfs_mutex));
1805	if (attr == &dev_attr_enable) {
1806	if (!!value == !!bt) {
1807	ret = 0;
1808	goto out_unlock_bdev;
1809	}
1810	if (value)
1811	ret = blk_trace_setup_queue(q, bdev);
1812	else
1813	ret = blk_trace_remove_queue(q);
1814	goto out_unlock_bdev;
1815	}
1816
1817	ret = 0;
1818	if (bt == NULL) {
1819	ret = blk_trace_setup_queue(q, bdev);
1820	bt = rcu_dereference_protected(q->blk_trace,
1821	lockdep_is_held(&q->debugfs_mutex));
1822	}
1823
1824	if (ret == 0) {
1825	if (attr == &dev_attr_act_mask)
1826	bt->act_mask = value;
1827	else if (attr == &dev_attr_pid)
1828	bt->pid = value;
1829	else if (attr == &dev_attr_start_lba)
1830	bt->start_lba = value;
1831	else if (attr == &dev_attr_end_lba)
1832	bt->end_lba = value;
1833	}
1834
1835	out_unlock_bdev:
1836	mutex_unlock(lock: &q->debugfs_mutex);
1837	out:
1838	return ret ? ret : count;
1839	}
1840	#endif /* CONFIG_BLK_DEV_IO_TRACE */
1841
1842	#ifdef CONFIG_EVENT_TRACING
1843
1844	/**
1845	* blk_fill_rwbs - Fill the buffer rwbs by mapping op to character string.
1846	* @rwbs: buffer to be filled
1847	* @opf: request operation type (REQ_OP_XXX) and flags for the tracepoint
1848	*
1849	* Description:
1850	* Maps each request operation and flag to a single character and fills the
1851	* buffer provided by the caller with resulting string.
1852	*
1853	**/
1854	void blk_fill_rwbs(char *rwbs, blk_opf_t opf)
1855	{
1856	int i = 0;
1857
1858	if (opf & REQ_PREFLUSH)
1859	rwbs[i++] = 'F';
1860
1861	switch (opf & REQ_OP_MASK) {
1862	case REQ_OP_WRITE:
1863	rwbs[i++] = 'W';
1864	break;
1865	case REQ_OP_DISCARD:
1866	rwbs[i++] = 'D';
1867	break;
1868	case REQ_OP_SECURE_ERASE:
1869	rwbs[i++] = 'D';
1870	rwbs[i++] = 'E';
1871	break;
1872	case REQ_OP_FLUSH:
1873	rwbs[i++] = 'F';
1874	break;
1875	case REQ_OP_READ:
1876	rwbs[i++] = 'R';
1877	break;
1878	default:
1879	rwbs[i++] = 'N';
1880	}
1881
1882	if (opf & REQ_FUA)
1883	rwbs[i++] = 'F';
1884	if (opf & REQ_RAHEAD)
1885	rwbs[i++] = 'A';
1886	if (opf & REQ_SYNC)
1887	rwbs[i++] = 'S';
1888	if (opf & REQ_META)
1889	rwbs[i++] = 'M';
1890	if (opf & REQ_ATOMIC)
1891	rwbs[i++] = 'U';
1892
1893	rwbs[i] = '\0';
1894	}
1895	EXPORT_SYMBOL_GPL(blk_fill_rwbs);
1896
1897	#endif /* CONFIG_EVENT_TRACING */
1898
1899