1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (C) 2006 Jens Axboe <axboe@kernel.dk>
7 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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>
23 #include "../../block/blk.h"
25 #include <trace/events/block.h>
27 #include "trace_output.h"
29 #ifdef CONFIG_BLK_DEV_IO_TRACE
31 static unsigned int blktrace_seq __read_mostly = 1;
33 static struct trace_array *blk_tr;
34 static bool blk_tracer_enabled __read_mostly;
36 static LIST_HEAD(running_trace_list);
37 static __cacheline_aligned_in_smp DEFINE_RAW_SPINLOCK(running_trace_lock);
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
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) },
54 static struct tracer_flags blk_tracer_flags = {
56 .opts = blk_tracer_opts,
59 /* Global reference count of probes */
60 static DEFINE_MUTEX(blk_probe_mutex);
61 static int blk_probes_ref;
63 static void blk_register_tracepoints(void);
64 static void blk_unregister_tracepoints(void);
67 * Send out a notify message.
69 static void trace_note(struct blk_trace *bt, pid_t pid, int action,
70 const void *data, size_t len, u64 cgid)
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;
81 buffer = blk_tr->array_buffer.buffer;
82 trace_ctx = tracing_gen_ctx_flags(0);
83 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
84 sizeof(*t) + len + cgid_len,
88 t = ring_buffer_event_data(event);
95 t = relay_reserve(bt->rchan, sizeof(*t) + len + cgid_len);
97 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
98 t->time = ktime_to_ns(ktime_get());
101 t->action = action | (cgid ? __BLK_TN_CGROUP : 0);
104 t->pdu_len = len + cgid_len;
106 memcpy((void *)t + sizeof(*t), &cgid, cgid_len);
107 memcpy((void *) t + sizeof(*t) + cgid_len, data, len);
110 trace_buffer_unlock_commit(blk_tr, buffer, event, trace_ctx);
115 * Send out a notify for this process, if we haven't done so since a trace
118 static void trace_note_tsk(struct task_struct *tsk)
121 struct blk_trace *bt;
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, tsk->pid, BLK_TN_PROCESS, tsk->comm,
127 sizeof(tsk->comm), 0);
129 raw_spin_unlock_irqrestore(&running_trace_lock, flags);
132 static void trace_note_time(struct blk_trace *bt)
134 struct timespec64 now;
138 /* need to check user space to see if this breaks in y2038 or y2106 */
139 ktime_get_real_ts64(&now);
140 words[0] = (u32)now.tv_sec;
141 words[1] = now.tv_nsec;
143 local_irq_save(flags);
144 trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words), 0);
145 local_irq_restore(flags);
148 void __blk_trace_note_message(struct blk_trace *bt,
149 struct cgroup_subsys_state *css, const char *fmt, ...)
157 if (unlikely(bt->trace_state != Blktrace_running &&
158 !blk_tracer_enabled))
162 * If the BLK_TC_NOTIFY action mask isn't set, don't send any note
163 * message to the trace.
165 if (!(bt->act_mask & BLK_TC_NOTIFY))
168 local_irq_save(flags);
169 buf = this_cpu_ptr(bt->msg_data);
171 n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args);
174 #ifdef CONFIG_BLK_CGROUP
175 if (css && (blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP))
176 cgid = cgroup_id(css->cgroup);
180 trace_note(bt, current->pid, BLK_TN_MESSAGE, buf, n, cgid);
181 local_irq_restore(flags);
183 EXPORT_SYMBOL_GPL(__blk_trace_note_message);
185 static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
188 if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0)
190 if (sector && (sector < bt->start_lba || sector > bt->end_lba))
192 if (bt->pid && pid != bt->pid)
199 * Data direction bit lookup
201 static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ),
202 BLK_TC_ACT(BLK_TC_WRITE) };
204 #define BLK_TC_RAHEAD BLK_TC_AHEAD
205 #define BLK_TC_PREFLUSH BLK_TC_FLUSH
207 /* The ilog2() calls fall out because they're constant */
208 #define MASK_TC_BIT(rw, __name) ((rw & REQ_ ## __name) << \
209 (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - __REQ_ ## __name))
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.
215 static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
216 int op, int op_flags, u32 what, int error, int pdu_len,
217 void *pdu_data, u64 cgid)
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;
228 bool blk_tracer = blk_tracer_enabled;
229 ssize_t cgid_len = cgid ? sizeof(cgid) : 0;
231 if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer))
234 what |= ddir_act[op_is_write(op) ? WRITE : READ];
235 what |= MASK_TC_BIT(op_flags, SYNC);
236 what |= MASK_TC_BIT(op_flags, RAHEAD);
237 what |= MASK_TC_BIT(op_flags, META);
238 what |= MASK_TC_BIT(op_flags, PREFLUSH);
239 what |= MASK_TC_BIT(op_flags, FUA);
240 if (op == REQ_OP_DISCARD || op == REQ_OP_SECURE_ERASE)
241 what |= BLK_TC_ACT(BLK_TC_DISCARD);
242 if (op == REQ_OP_FLUSH)
243 what |= BLK_TC_ACT(BLK_TC_FLUSH);
245 what |= __BLK_TA_CGROUP;
248 if (act_log_check(bt, what, sector, pid))
250 cpu = raw_smp_processor_id();
253 tracing_record_cmdline(current);
255 buffer = blk_tr->array_buffer.buffer;
256 trace_ctx = tracing_gen_ctx_flags(0);
257 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
258 sizeof(*t) + pdu_len + cgid_len,
262 t = ring_buffer_event_data(event);
266 if (unlikely(tsk->btrace_seq != blktrace_seq))
270 * A word about the locking here - we disable interrupts to reserve
271 * some space in the relay per-cpu buffer, to prevent an irq
272 * from coming in and stepping on our toes.
274 local_irq_save(flags);
275 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len + cgid_len);
277 sequence = per_cpu_ptr(bt->sequence, cpu);
279 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
280 t->sequence = ++(*sequence);
281 t->time = ktime_to_ns(ktime_get());
284 * These two are not needed in ftrace as they are in the
285 * generic trace_entry, filled by tracing_generic_entry_update,
286 * but for the trace_event->bin() synthesizer benefit we do it
297 t->pdu_len = pdu_len + cgid_len;
300 memcpy((void *)t + sizeof(*t), &cgid, cgid_len);
302 memcpy((void *)t + sizeof(*t) + cgid_len, pdu_data, pdu_len);
305 trace_buffer_unlock_commit(blk_tr, buffer, event, trace_ctx);
310 local_irq_restore(flags);
313 static void blk_trace_free(struct request_queue *q, struct blk_trace *bt)
315 relay_close(bt->rchan);
318 * If 'bt->dir' is not set, then both 'dropped' and 'msg' are created
319 * under 'q->debugfs_dir', thus lookup and remove them.
322 debugfs_remove(debugfs_lookup("dropped", q->debugfs_dir));
323 debugfs_remove(debugfs_lookup("msg", q->debugfs_dir));
325 debugfs_remove(bt->dir);
327 free_percpu(bt->sequence);
328 free_percpu(bt->msg_data);
332 static void get_probe_ref(void)
334 mutex_lock(&blk_probe_mutex);
335 if (++blk_probes_ref == 1)
336 blk_register_tracepoints();
337 mutex_unlock(&blk_probe_mutex);
340 static void put_probe_ref(void)
342 mutex_lock(&blk_probe_mutex);
343 if (!--blk_probes_ref)
344 blk_unregister_tracepoints();
345 mutex_unlock(&blk_probe_mutex);
348 static void blk_trace_cleanup(struct request_queue *q, struct blk_trace *bt)
351 blk_trace_free(q, bt);
355 static int __blk_trace_remove(struct request_queue *q)
357 struct blk_trace *bt;
359 bt = rcu_replace_pointer(q->blk_trace, NULL,
360 lockdep_is_held(&q->debugfs_mutex));
364 if (bt->trace_state != Blktrace_running)
365 blk_trace_cleanup(q, bt);
370 int blk_trace_remove(struct request_queue *q)
374 mutex_lock(&q->debugfs_mutex);
375 ret = __blk_trace_remove(q);
376 mutex_unlock(&q->debugfs_mutex);
380 EXPORT_SYMBOL_GPL(blk_trace_remove);
382 static ssize_t blk_dropped_read(struct file *filp, char __user *buffer,
383 size_t count, loff_t *ppos)
385 struct blk_trace *bt = filp->private_data;
388 snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped));
390 return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf));
393 static const struct file_operations blk_dropped_fops = {
394 .owner = THIS_MODULE,
396 .read = blk_dropped_read,
397 .llseek = default_llseek,
400 static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
401 size_t count, loff_t *ppos)
404 struct blk_trace *bt;
406 if (count >= BLK_TN_MAX_MSG)
409 msg = memdup_user_nul(buffer, count);
413 bt = filp->private_data;
414 __blk_trace_note_message(bt, NULL, "%s", msg);
420 static const struct file_operations blk_msg_fops = {
421 .owner = THIS_MODULE,
423 .write = blk_msg_write,
424 .llseek = noop_llseek,
428 * Keep track of how many times we encountered a full subbuffer, to aid
429 * the user space app in telling how many lost events there were.
431 static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
432 void *prev_subbuf, size_t prev_padding)
434 struct blk_trace *bt;
436 if (!relay_buf_full(buf))
439 bt = buf->chan->private_data;
440 atomic_inc(&bt->dropped);
444 static int blk_remove_buf_file_callback(struct dentry *dentry)
446 debugfs_remove(dentry);
451 static struct dentry *blk_create_buf_file_callback(const char *filename,
452 struct dentry *parent,
454 struct rchan_buf *buf,
457 return debugfs_create_file(filename, mode, parent, buf,
458 &relay_file_operations);
461 static const struct rchan_callbacks blk_relay_callbacks = {
462 .subbuf_start = blk_subbuf_start_callback,
463 .create_buf_file = blk_create_buf_file_callback,
464 .remove_buf_file = blk_remove_buf_file_callback,
467 static void blk_trace_setup_lba(struct blk_trace *bt,
468 struct block_device *bdev)
471 bt->start_lba = bdev->bd_start_sect;
472 bt->end_lba = bdev->bd_start_sect + bdev_nr_sectors(bdev);
480 * Setup everything required to start tracing
482 static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
483 struct block_device *bdev,
484 struct blk_user_trace_setup *buts)
486 struct blk_trace *bt = NULL;
487 struct dentry *dir = NULL;
490 lockdep_assert_held(&q->debugfs_mutex);
492 if (!buts->buf_size || !buts->buf_nr)
495 strncpy(buts->name, name, BLKTRACE_BDEV_SIZE);
496 buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0';
499 * some device names have larger paths - convert the slashes
500 * to underscores for this to work as expected
502 strreplace(buts->name, '/', '_');
505 * bdev can be NULL, as with scsi-generic, this is a helpful as
508 if (rcu_dereference_protected(q->blk_trace,
509 lockdep_is_held(&q->debugfs_mutex))) {
510 pr_warn("Concurrent blktraces are not allowed on %s\n",
515 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
520 bt->sequence = alloc_percpu(unsigned long);
524 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
529 * When tracing the whole disk reuse the existing debugfs directory
530 * created by the block layer on init. For partitions block devices,
531 * and scsi-generic block devices we create a temporary new debugfs
532 * directory that will be removed once the trace ends.
534 if (bdev && !bdev_is_partition(bdev))
535 dir = q->debugfs_dir;
537 bt->dir = dir = debugfs_create_dir(buts->name, blk_debugfs_root);
540 * As blktrace relies on debugfs for its interface the debugfs directory
541 * is required, contrary to the usual mantra of not checking for debugfs
542 * files or directories.
544 if (IS_ERR_OR_NULL(dir)) {
545 pr_warn("debugfs_dir not present for %s so skipping\n",
552 atomic_set(&bt->dropped, 0);
553 INIT_LIST_HEAD(&bt->running_list);
556 debugfs_create_file("dropped", 0444, dir, bt, &blk_dropped_fops);
557 debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
559 bt->rchan = relay_open("trace", dir, buts->buf_size,
560 buts->buf_nr, &blk_relay_callbacks, bt);
564 bt->act_mask = buts->act_mask;
566 bt->act_mask = (u16) -1;
568 blk_trace_setup_lba(bt, bdev);
570 /* overwrite with user settings */
572 bt->start_lba = buts->start_lba;
574 bt->end_lba = buts->end_lba;
577 bt->trace_state = Blktrace_setup;
579 rcu_assign_pointer(q->blk_trace, bt);
585 blk_trace_free(q, bt);
589 static int __blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
590 struct block_device *bdev, char __user *arg)
592 struct blk_user_trace_setup buts;
595 ret = copy_from_user(&buts, arg, sizeof(buts));
599 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
603 if (copy_to_user(arg, &buts, sizeof(buts))) {
604 __blk_trace_remove(q);
610 int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
611 struct block_device *bdev,
616 mutex_lock(&q->debugfs_mutex);
617 ret = __blk_trace_setup(q, name, dev, bdev, arg);
618 mutex_unlock(&q->debugfs_mutex);
622 EXPORT_SYMBOL_GPL(blk_trace_setup);
624 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
625 static int compat_blk_trace_setup(struct request_queue *q, char *name,
626 dev_t dev, struct block_device *bdev,
629 struct blk_user_trace_setup buts;
630 struct compat_blk_user_trace_setup cbuts;
633 if (copy_from_user(&cbuts, arg, sizeof(cbuts)))
636 buts = (struct blk_user_trace_setup) {
637 .act_mask = cbuts.act_mask,
638 .buf_size = cbuts.buf_size,
639 .buf_nr = cbuts.buf_nr,
640 .start_lba = cbuts.start_lba,
641 .end_lba = cbuts.end_lba,
645 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
649 if (copy_to_user(arg, &buts.name, ARRAY_SIZE(buts.name))) {
650 __blk_trace_remove(q);
658 static int __blk_trace_startstop(struct request_queue *q, int start)
661 struct blk_trace *bt;
663 bt = rcu_dereference_protected(q->blk_trace,
664 lockdep_is_held(&q->debugfs_mutex));
669 * For starting a trace, we can transition from a setup or stopped
670 * trace. For stopping a trace, the state must be running
674 if (bt->trace_state == Blktrace_setup ||
675 bt->trace_state == Blktrace_stopped) {
678 bt->trace_state = Blktrace_running;
679 raw_spin_lock_irq(&running_trace_lock);
680 list_add(&bt->running_list, &running_trace_list);
681 raw_spin_unlock_irq(&running_trace_lock);
687 if (bt->trace_state == Blktrace_running) {
688 bt->trace_state = Blktrace_stopped;
689 raw_spin_lock_irq(&running_trace_lock);
690 list_del_init(&bt->running_list);
691 raw_spin_unlock_irq(&running_trace_lock);
692 relay_flush(bt->rchan);
700 int blk_trace_startstop(struct request_queue *q, int start)
704 mutex_lock(&q->debugfs_mutex);
705 ret = __blk_trace_startstop(q, start);
706 mutex_unlock(&q->debugfs_mutex);
710 EXPORT_SYMBOL_GPL(blk_trace_startstop);
713 * When reading or writing the blktrace sysfs files, the references to the
714 * opened sysfs or device files should prevent the underlying block device
715 * from being removed. So no further delete protection is really needed.
719 * blk_trace_ioctl: - handle the ioctls associated with tracing
720 * @bdev: the block device
721 * @cmd: the ioctl cmd
722 * @arg: the argument data, if any
725 int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
727 struct request_queue *q;
729 char b[BDEVNAME_SIZE];
731 q = bdev_get_queue(bdev);
735 mutex_lock(&q->debugfs_mutex);
740 ret = __blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
742 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
743 case BLKTRACESETUP32:
745 ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
752 ret = __blk_trace_startstop(q, start);
754 case BLKTRACETEARDOWN:
755 ret = __blk_trace_remove(q);
762 mutex_unlock(&q->debugfs_mutex);
767 * blk_trace_shutdown: - stop and cleanup trace structures
768 * @q: the request queue associated with the device
771 void blk_trace_shutdown(struct request_queue *q)
773 if (rcu_dereference_protected(q->blk_trace,
774 lockdep_is_held(&q->debugfs_mutex))) {
775 __blk_trace_startstop(q, 0);
776 __blk_trace_remove(q);
780 #ifdef CONFIG_BLK_CGROUP
781 static u64 blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio)
783 struct cgroup_subsys_state *blkcg_css;
784 struct blk_trace *bt;
786 /* We don't use the 'bt' value here except as an optimization... */
787 bt = rcu_dereference_protected(q->blk_trace, 1);
788 if (!bt || !(blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP))
791 blkcg_css = bio_blkcg_css(bio);
794 return cgroup_id(blkcg_css->cgroup);
797 static u64 blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio)
804 blk_trace_request_get_cgid(struct request *rq)
808 /* Use the first bio */
809 return blk_trace_bio_get_cgid(rq->q, rq->bio);
817 * blk_add_trace_rq - Add a trace for a request oriented action
818 * @rq: the source request
819 * @error: return status to log
820 * @nr_bytes: number of completed bytes
822 * @cgid: the cgroup info
825 * Records an action against a request. Will log the bio offset + size.
828 static void blk_add_trace_rq(struct request *rq, blk_status_t error,
829 unsigned int nr_bytes, u32 what, u64 cgid)
831 struct blk_trace *bt;
834 bt = rcu_dereference(rq->q->blk_trace);
840 if (blk_rq_is_passthrough(rq))
841 what |= BLK_TC_ACT(BLK_TC_PC);
843 what |= BLK_TC_ACT(BLK_TC_FS);
845 __blk_add_trace(bt, blk_rq_trace_sector(rq), nr_bytes, req_op(rq),
846 rq->cmd_flags, what, blk_status_to_errno(error), 0,
851 static void blk_add_trace_rq_insert(void *ignore, struct request *rq)
853 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_INSERT,
854 blk_trace_request_get_cgid(rq));
857 static void blk_add_trace_rq_issue(void *ignore, struct request *rq)
859 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_ISSUE,
860 blk_trace_request_get_cgid(rq));
863 static void blk_add_trace_rq_merge(void *ignore, struct request *rq)
865 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_BACKMERGE,
866 blk_trace_request_get_cgid(rq));
869 static void blk_add_trace_rq_requeue(void *ignore, struct request *rq)
871 blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_REQUEUE,
872 blk_trace_request_get_cgid(rq));
875 static void blk_add_trace_rq_complete(void *ignore, struct request *rq,
876 blk_status_t error, unsigned int nr_bytes)
878 blk_add_trace_rq(rq, error, nr_bytes, BLK_TA_COMPLETE,
879 blk_trace_request_get_cgid(rq));
883 * blk_add_trace_bio - Add a trace for a bio oriented action
884 * @q: queue the io is for
885 * @bio: the source bio
887 * @error: error, if any
890 * Records an action against a bio. Will log the bio offset + size.
893 static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
896 struct blk_trace *bt;
899 bt = rcu_dereference(q->blk_trace);
905 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
906 bio_op(bio), bio->bi_opf, what, error, 0, NULL,
907 blk_trace_bio_get_cgid(q, bio));
911 static void blk_add_trace_bio_bounce(void *ignore, struct bio *bio)
913 blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_BOUNCE, 0);
916 static void blk_add_trace_bio_complete(void *ignore,
917 struct request_queue *q, struct bio *bio)
919 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE,
920 blk_status_to_errno(bio->bi_status));
923 static void blk_add_trace_bio_backmerge(void *ignore, struct bio *bio)
925 blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_BACKMERGE,
929 static void blk_add_trace_bio_frontmerge(void *ignore, struct bio *bio)
931 blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_FRONTMERGE,
935 static void blk_add_trace_bio_queue(void *ignore, struct bio *bio)
937 blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_QUEUE, 0);
940 static void blk_add_trace_getrq(void *ignore, struct bio *bio)
942 blk_add_trace_bio(bio->bi_bdev->bd_disk->queue, bio, BLK_TA_GETRQ, 0);
945 static void blk_add_trace_plug(void *ignore, struct request_queue *q)
947 struct blk_trace *bt;
950 bt = rcu_dereference(q->blk_trace);
952 __blk_add_trace(bt, 0, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL, 0);
956 static void blk_add_trace_unplug(void *ignore, struct request_queue *q,
957 unsigned int depth, bool explicit)
959 struct blk_trace *bt;
962 bt = rcu_dereference(q->blk_trace);
964 __be64 rpdu = cpu_to_be64(depth);
968 what = BLK_TA_UNPLUG_IO;
970 what = BLK_TA_UNPLUG_TIMER;
972 __blk_add_trace(bt, 0, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu, 0);
977 static void blk_add_trace_split(void *ignore, struct bio *bio, unsigned int pdu)
979 struct request_queue *q = bio->bi_bdev->bd_disk->queue;
980 struct blk_trace *bt;
983 bt = rcu_dereference(q->blk_trace);
985 __be64 rpdu = cpu_to_be64(pdu);
987 __blk_add_trace(bt, bio->bi_iter.bi_sector,
988 bio->bi_iter.bi_size, bio_op(bio), bio->bi_opf,
990 blk_status_to_errno(bio->bi_status),
992 blk_trace_bio_get_cgid(q, bio));
998 * blk_add_trace_bio_remap - Add a trace for a bio-remap operation
999 * @ignore: trace callback data parameter (not used)
1000 * @bio: the source bio
1001 * @dev: source device
1002 * @from: source sector
1004 * Called after a bio is remapped to a different device and/or sector.
1006 static void blk_add_trace_bio_remap(void *ignore, struct bio *bio, dev_t dev,
1009 struct request_queue *q = bio->bi_bdev->bd_disk->queue;
1010 struct blk_trace *bt;
1011 struct blk_io_trace_remap r;
1014 bt = rcu_dereference(q->blk_trace);
1020 r.device_from = cpu_to_be32(dev);
1021 r.device_to = cpu_to_be32(bio_dev(bio));
1022 r.sector_from = cpu_to_be64(from);
1024 __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
1025 bio_op(bio), bio->bi_opf, BLK_TA_REMAP,
1026 blk_status_to_errno(bio->bi_status),
1027 sizeof(r), &r, blk_trace_bio_get_cgid(q, bio));
1032 * blk_add_trace_rq_remap - Add a trace for a request-remap operation
1033 * @ignore: trace callback data parameter (not used)
1034 * @rq: the source request
1035 * @dev: target device
1036 * @from: source sector
1039 * Device mapper remaps request to other devices.
1040 * Add a trace for that action.
1043 static void blk_add_trace_rq_remap(void *ignore, struct request *rq, dev_t dev,
1046 struct blk_trace *bt;
1047 struct blk_io_trace_remap r;
1050 bt = rcu_dereference(rq->q->blk_trace);
1056 r.device_from = cpu_to_be32(dev);
1057 r.device_to = cpu_to_be32(disk_devt(rq->q->disk));
1058 r.sector_from = cpu_to_be64(from);
1060 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
1061 rq_data_dir(rq), 0, BLK_TA_REMAP, 0,
1062 sizeof(r), &r, blk_trace_request_get_cgid(rq));
1067 * blk_add_driver_data - Add binary message with driver-specific data
1069 * @data: driver-specific data
1070 * @len: length of driver-specific data
1073 * Some drivers might want to write driver-specific data per request.
1076 void blk_add_driver_data(struct request *rq, void *data, size_t len)
1078 struct blk_trace *bt;
1081 bt = rcu_dereference(rq->q->blk_trace);
1087 __blk_add_trace(bt, blk_rq_trace_sector(rq), blk_rq_bytes(rq), 0, 0,
1088 BLK_TA_DRV_DATA, 0, len, data,
1089 blk_trace_request_get_cgid(rq));
1092 EXPORT_SYMBOL_GPL(blk_add_driver_data);
1094 static void blk_register_tracepoints(void)
1098 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1100 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1102 ret = register_trace_block_rq_merge(blk_add_trace_rq_merge, NULL);
1104 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1106 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1108 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1110 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1112 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1114 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1116 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1118 ret = register_trace_block_getrq(blk_add_trace_getrq, NULL);
1120 ret = register_trace_block_plug(blk_add_trace_plug, NULL);
1122 ret = register_trace_block_unplug(blk_add_trace_unplug, NULL);
1124 ret = register_trace_block_split(blk_add_trace_split, NULL);
1126 ret = register_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1128 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1132 static void blk_unregister_tracepoints(void)
1134 unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1135 unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
1136 unregister_trace_block_split(blk_add_trace_split, NULL);
1137 unregister_trace_block_unplug(blk_add_trace_unplug, NULL);
1138 unregister_trace_block_plug(blk_add_trace_plug, NULL);
1139 unregister_trace_block_getrq(blk_add_trace_getrq, NULL);
1140 unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1141 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1142 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1143 unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1144 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1145 unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1146 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1147 unregister_trace_block_rq_merge(blk_add_trace_rq_merge, NULL);
1148 unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1149 unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1151 tracepoint_synchronize_unregister();
1155 * struct blk_io_tracer formatting routines
1158 static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
1161 int tc = t->action >> BLK_TC_SHIFT;
1163 if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) {
1168 if (tc & BLK_TC_FLUSH)
1171 if (tc & BLK_TC_DISCARD)
1173 else if (tc & BLK_TC_WRITE)
1180 if (tc & BLK_TC_FUA)
1182 if (tc & BLK_TC_AHEAD)
1184 if (tc & BLK_TC_SYNC)
1186 if (tc & BLK_TC_META)
1193 const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent)
1195 return (const struct blk_io_trace *)ent;
1198 static inline const void *pdu_start(const struct trace_entry *ent, bool has_cg)
1200 return (void *)(te_blk_io_trace(ent) + 1) + (has_cg ? sizeof(u64) : 0);
1203 static inline u64 t_cgid(const struct trace_entry *ent)
1205 return *(u64 *)(te_blk_io_trace(ent) + 1);
1208 static inline int pdu_real_len(const struct trace_entry *ent, bool has_cg)
1210 return te_blk_io_trace(ent)->pdu_len - (has_cg ? sizeof(u64) : 0);
1213 static inline u32 t_action(const struct trace_entry *ent)
1215 return te_blk_io_trace(ent)->action;
1218 static inline u32 t_bytes(const struct trace_entry *ent)
1220 return te_blk_io_trace(ent)->bytes;
1223 static inline u32 t_sec(const struct trace_entry *ent)
1225 return te_blk_io_trace(ent)->bytes >> 9;
1228 static inline unsigned long long t_sector(const struct trace_entry *ent)
1230 return te_blk_io_trace(ent)->sector;
1233 static inline __u16 t_error(const struct trace_entry *ent)
1235 return te_blk_io_trace(ent)->error;
1238 static __u64 get_pdu_int(const struct trace_entry *ent, bool has_cg)
1240 const __be64 *val = pdu_start(ent, has_cg);
1241 return be64_to_cpu(*val);
1244 typedef void (blk_log_action_t) (struct trace_iterator *iter, const char *act,
1247 static void blk_log_action_classic(struct trace_iterator *iter, const char *act,
1250 char rwbs[RWBS_LEN];
1251 unsigned long long ts = iter->ts;
1252 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC);
1253 unsigned secs = (unsigned long)ts;
1254 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1258 trace_seq_printf(&iter->seq,
1259 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
1260 MAJOR(t->device), MINOR(t->device), iter->cpu,
1261 secs, nsec_rem, iter->ent->pid, act, rwbs);
1264 static void blk_log_action(struct trace_iterator *iter, const char *act,
1267 char rwbs[RWBS_LEN];
1268 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1272 u64 id = t_cgid(iter->ent);
1274 if (blk_tracer_flags.val & TRACE_BLK_OPT_CGNAME) {
1275 char blkcg_name_buf[NAME_MAX + 1] = "<...>";
1277 cgroup_path_from_kernfs_id(id, blkcg_name_buf,
1278 sizeof(blkcg_name_buf));
1279 trace_seq_printf(&iter->seq, "%3d,%-3d %s %2s %3s ",
1280 MAJOR(t->device), MINOR(t->device),
1281 blkcg_name_buf, act, rwbs);
1284 * The cgid portion used to be "INO,GEN". Userland
1285 * builds a FILEID_INO32_GEN fid out of them and
1286 * opens the cgroup using open_by_handle_at(2).
1287 * While 32bit ino setups are still the same, 64bit
1288 * ones now use the 64bit ino as the whole ID and
1289 * no longer use generation.
1291 * Regardless of the content, always output
1292 * "LOW32,HIGH32" so that FILEID_INO32_GEN fid can
1293 * be mapped back to @id on both 64 and 32bit ino
1294 * setups. See __kernfs_fh_to_dentry().
1296 trace_seq_printf(&iter->seq,
1297 "%3d,%-3d %llx,%-llx %2s %3s ",
1298 MAJOR(t->device), MINOR(t->device),
1299 id & U32_MAX, id >> 32, act, rwbs);
1302 trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
1303 MAJOR(t->device), MINOR(t->device), act, rwbs);
1306 static void blk_log_dump_pdu(struct trace_seq *s,
1307 const struct trace_entry *ent, bool has_cg)
1309 const unsigned char *pdu_buf;
1313 pdu_buf = pdu_start(ent, has_cg);
1314 pdu_len = pdu_real_len(ent, has_cg);
1319 /* find the last zero that needs to be printed */
1320 for (end = pdu_len - 1; end >= 0; end--)
1325 trace_seq_putc(s, '(');
1327 for (i = 0; i < pdu_len; i++) {
1329 trace_seq_printf(s, "%s%02x",
1330 i == 0 ? "" : " ", pdu_buf[i]);
1333 * stop when the rest is just zeros and indicate so
1334 * with a ".." appended
1336 if (i == end && end != pdu_len - 1) {
1337 trace_seq_puts(s, " ..) ");
1342 trace_seq_puts(s, ") ");
1345 static void blk_log_generic(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1347 char cmd[TASK_COMM_LEN];
1349 trace_find_cmdline(ent->pid, cmd);
1351 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1352 trace_seq_printf(s, "%u ", t_bytes(ent));
1353 blk_log_dump_pdu(s, ent, has_cg);
1354 trace_seq_printf(s, "[%s]\n", cmd);
1357 trace_seq_printf(s, "%llu + %u [%s]\n",
1358 t_sector(ent), t_sec(ent), cmd);
1360 trace_seq_printf(s, "[%s]\n", cmd);
1364 static void blk_log_with_error(struct trace_seq *s,
1365 const struct trace_entry *ent, bool has_cg)
1367 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1368 blk_log_dump_pdu(s, ent, has_cg);
1369 trace_seq_printf(s, "[%d]\n", t_error(ent));
1372 trace_seq_printf(s, "%llu + %u [%d]\n",
1374 t_sec(ent), t_error(ent));
1376 trace_seq_printf(s, "%llu [%d]\n",
1377 t_sector(ent), t_error(ent));
1381 static void blk_log_remap(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1383 const struct blk_io_trace_remap *__r = pdu_start(ent, has_cg);
1385 trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
1386 t_sector(ent), t_sec(ent),
1387 MAJOR(be32_to_cpu(__r->device_from)),
1388 MINOR(be32_to_cpu(__r->device_from)),
1389 be64_to_cpu(__r->sector_from));
1392 static void blk_log_plug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1394 char cmd[TASK_COMM_LEN];
1396 trace_find_cmdline(ent->pid, cmd);
1398 trace_seq_printf(s, "[%s]\n", cmd);
1401 static void blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1403 char cmd[TASK_COMM_LEN];
1405 trace_find_cmdline(ent->pid, cmd);
1407 trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent, has_cg));
1410 static void blk_log_split(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
1412 char cmd[TASK_COMM_LEN];
1414 trace_find_cmdline(ent->pid, cmd);
1416 trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
1417 get_pdu_int(ent, has_cg), cmd);
1420 static void blk_log_msg(struct trace_seq *s, const struct trace_entry *ent,
1424 trace_seq_putmem(s, pdu_start(ent, has_cg),
1425 pdu_real_len(ent, has_cg));
1426 trace_seq_putc(s, '\n');
1430 * struct tracer operations
1433 static void blk_tracer_print_header(struct seq_file *m)
1435 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1437 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n"
1441 static void blk_tracer_start(struct trace_array *tr)
1443 blk_tracer_enabled = true;
1446 static int blk_tracer_init(struct trace_array *tr)
1449 blk_tracer_start(tr);
1453 static void blk_tracer_stop(struct trace_array *tr)
1455 blk_tracer_enabled = false;
1458 static void blk_tracer_reset(struct trace_array *tr)
1460 blk_tracer_stop(tr);
1463 static const struct {
1465 void (*print)(struct trace_seq *s, const struct trace_entry *ent,
1468 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic },
1469 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic },
1470 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic },
1471 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic },
1472 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic },
1473 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error },
1474 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic },
1475 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error },
1476 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug },
1477 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug },
1478 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug },
1479 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic },
1480 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split },
1481 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic },
1482 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap },
1485 static enum print_line_t print_one_line(struct trace_iterator *iter,
1488 struct trace_array *tr = iter->tr;
1489 struct trace_seq *s = &iter->seq;
1490 const struct blk_io_trace *t;
1493 blk_log_action_t *log_action;
1496 t = te_blk_io_trace(iter->ent);
1497 what = (t->action & ((1 << BLK_TC_SHIFT) - 1)) & ~__BLK_TA_CGROUP;
1498 long_act = !!(tr->trace_flags & TRACE_ITER_VERBOSE);
1499 log_action = classic ? &blk_log_action_classic : &blk_log_action;
1500 has_cg = t->action & __BLK_TA_CGROUP;
1502 if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) {
1503 log_action(iter, long_act ? "message" : "m", has_cg);
1504 blk_log_msg(s, iter->ent, has_cg);
1505 return trace_handle_return(s);
1508 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
1509 trace_seq_printf(s, "Unknown action %x\n", what);
1511 log_action(iter, what2act[what].act[long_act], has_cg);
1512 what2act[what].print(s, iter->ent, has_cg);
1515 return trace_handle_return(s);
1518 static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
1519 int flags, struct trace_event *event)
1521 return print_one_line(iter, false);
1524 static void blk_trace_synthesize_old_trace(struct trace_iterator *iter)
1526 struct trace_seq *s = &iter->seq;
1527 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
1528 const int offset = offsetof(struct blk_io_trace, sector);
1529 struct blk_io_trace old = {
1530 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
1534 trace_seq_putmem(s, &old, offset);
1535 trace_seq_putmem(s, &t->sector,
1536 sizeof(old) - offset + t->pdu_len);
1539 static enum print_line_t
1540 blk_trace_event_print_binary(struct trace_iterator *iter, int flags,
1541 struct trace_event *event)
1543 blk_trace_synthesize_old_trace(iter);
1545 return trace_handle_return(&iter->seq);
1548 static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
1550 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1551 return TRACE_TYPE_UNHANDLED;
1553 return print_one_line(iter, true);
1557 blk_tracer_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
1559 /* don't output context-info for blk_classic output */
1560 if (bit == TRACE_BLK_OPT_CLASSIC) {
1562 tr->trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
1564 tr->trace_flags |= TRACE_ITER_CONTEXT_INFO;
1569 static struct tracer blk_tracer __read_mostly = {
1571 .init = blk_tracer_init,
1572 .reset = blk_tracer_reset,
1573 .start = blk_tracer_start,
1574 .stop = blk_tracer_stop,
1575 .print_header = blk_tracer_print_header,
1576 .print_line = blk_tracer_print_line,
1577 .flags = &blk_tracer_flags,
1578 .set_flag = blk_tracer_set_flag,
1581 static struct trace_event_functions trace_blk_event_funcs = {
1582 .trace = blk_trace_event_print,
1583 .binary = blk_trace_event_print_binary,
1586 static struct trace_event trace_blk_event = {
1588 .funcs = &trace_blk_event_funcs,
1591 static int __init init_blk_tracer(void)
1593 if (!register_trace_event(&trace_blk_event)) {
1594 pr_warn("Warning: could not register block events\n");
1598 if (register_tracer(&blk_tracer) != 0) {
1599 pr_warn("Warning: could not register the block tracer\n");
1600 unregister_trace_event(&trace_blk_event);
1607 device_initcall(init_blk_tracer);
1609 static int blk_trace_remove_queue(struct request_queue *q)
1611 struct blk_trace *bt;
1613 bt = rcu_replace_pointer(q->blk_trace, NULL,
1614 lockdep_is_held(&q->debugfs_mutex));
1618 if (bt->trace_state == Blktrace_running) {
1619 bt->trace_state = Blktrace_stopped;
1620 raw_spin_lock_irq(&running_trace_lock);
1621 list_del_init(&bt->running_list);
1622 raw_spin_unlock_irq(&running_trace_lock);
1623 relay_flush(bt->rchan);
1628 blk_trace_free(q, bt);
1633 * Setup everything required to start tracing
1635 static int blk_trace_setup_queue(struct request_queue *q,
1636 struct block_device *bdev)
1638 struct blk_trace *bt = NULL;
1641 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
1645 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
1649 bt->dev = bdev->bd_dev;
1650 bt->act_mask = (u16)-1;
1652 blk_trace_setup_lba(bt, bdev);
1654 rcu_assign_pointer(q->blk_trace, bt);
1659 blk_trace_free(q, bt);
1664 * sysfs interface to enable and configure tracing
1667 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1668 struct device_attribute *attr,
1670 static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1671 struct device_attribute *attr,
1672 const char *buf, size_t count);
1673 #define BLK_TRACE_DEVICE_ATTR(_name) \
1674 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
1675 sysfs_blk_trace_attr_show, \
1676 sysfs_blk_trace_attr_store)
1678 static BLK_TRACE_DEVICE_ATTR(enable);
1679 static BLK_TRACE_DEVICE_ATTR(act_mask);
1680 static BLK_TRACE_DEVICE_ATTR(pid);
1681 static BLK_TRACE_DEVICE_ATTR(start_lba);
1682 static BLK_TRACE_DEVICE_ATTR(end_lba);
1684 static struct attribute *blk_trace_attrs[] = {
1685 &dev_attr_enable.attr,
1686 &dev_attr_act_mask.attr,
1688 &dev_attr_start_lba.attr,
1689 &dev_attr_end_lba.attr,
1693 struct attribute_group blk_trace_attr_group = {
1695 .attrs = blk_trace_attrs,
1698 static const struct {
1702 { BLK_TC_READ, "read" },
1703 { BLK_TC_WRITE, "write" },
1704 { BLK_TC_FLUSH, "flush" },
1705 { BLK_TC_SYNC, "sync" },
1706 { BLK_TC_QUEUE, "queue" },
1707 { BLK_TC_REQUEUE, "requeue" },
1708 { BLK_TC_ISSUE, "issue" },
1709 { BLK_TC_COMPLETE, "complete" },
1710 { BLK_TC_FS, "fs" },
1711 { BLK_TC_PC, "pc" },
1712 { BLK_TC_NOTIFY, "notify" },
1713 { BLK_TC_AHEAD, "ahead" },
1714 { BLK_TC_META, "meta" },
1715 { BLK_TC_DISCARD, "discard" },
1716 { BLK_TC_DRV_DATA, "drv_data" },
1717 { BLK_TC_FUA, "fua" },
1720 static int blk_trace_str2mask(const char *str)
1724 char *buf, *s, *token;
1726 buf = kstrdup(str, GFP_KERNEL);
1732 token = strsep(&s, ",");
1739 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1740 if (strcasecmp(token, mask_maps[i].str) == 0) {
1741 mask |= mask_maps[i].mask;
1745 if (i == ARRAY_SIZE(mask_maps)) {
1755 static ssize_t blk_trace_mask2str(char *buf, int mask)
1760 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1761 if (mask & mask_maps[i].mask) {
1762 p += sprintf(p, "%s%s",
1763 (p == buf) ? "" : ",", mask_maps[i].str);
1771 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1772 struct device_attribute *attr,
1775 struct block_device *bdev = dev_to_bdev(dev);
1776 struct request_queue *q = bdev_get_queue(bdev);
1777 struct blk_trace *bt;
1778 ssize_t ret = -ENXIO;
1780 mutex_lock(&q->debugfs_mutex);
1782 bt = rcu_dereference_protected(q->blk_trace,
1783 lockdep_is_held(&q->debugfs_mutex));
1784 if (attr == &dev_attr_enable) {
1785 ret = sprintf(buf, "%u\n", !!bt);
1786 goto out_unlock_bdev;
1790 ret = sprintf(buf, "disabled\n");
1791 else if (attr == &dev_attr_act_mask)
1792 ret = blk_trace_mask2str(buf, bt->act_mask);
1793 else if (attr == &dev_attr_pid)
1794 ret = sprintf(buf, "%u\n", bt->pid);
1795 else if (attr == &dev_attr_start_lba)
1796 ret = sprintf(buf, "%llu\n", bt->start_lba);
1797 else if (attr == &dev_attr_end_lba)
1798 ret = sprintf(buf, "%llu\n", bt->end_lba);
1801 mutex_unlock(&q->debugfs_mutex);
1805 static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1806 struct device_attribute *attr,
1807 const char *buf, size_t count)
1809 struct block_device *bdev = dev_to_bdev(dev);
1810 struct request_queue *q = bdev_get_queue(bdev);
1811 struct blk_trace *bt;
1813 ssize_t ret = -EINVAL;
1818 if (attr == &dev_attr_act_mask) {
1819 if (kstrtoull(buf, 0, &value)) {
1820 /* Assume it is a list of trace category names */
1821 ret = blk_trace_str2mask(buf);
1827 if (kstrtoull(buf, 0, &value))
1831 mutex_lock(&q->debugfs_mutex);
1833 bt = rcu_dereference_protected(q->blk_trace,
1834 lockdep_is_held(&q->debugfs_mutex));
1835 if (attr == &dev_attr_enable) {
1836 if (!!value == !!bt) {
1838 goto out_unlock_bdev;
1841 ret = blk_trace_setup_queue(q, bdev);
1843 ret = blk_trace_remove_queue(q);
1844 goto out_unlock_bdev;
1849 ret = blk_trace_setup_queue(q, bdev);
1850 bt = rcu_dereference_protected(q->blk_trace,
1851 lockdep_is_held(&q->debugfs_mutex));
1855 if (attr == &dev_attr_act_mask)
1856 bt->act_mask = value;
1857 else if (attr == &dev_attr_pid)
1859 else if (attr == &dev_attr_start_lba)
1860 bt->start_lba = value;
1861 else if (attr == &dev_attr_end_lba)
1862 bt->end_lba = value;
1866 mutex_unlock(&q->debugfs_mutex);
1868 return ret ? ret : count;
1871 int blk_trace_init_sysfs(struct device *dev)
1873 return sysfs_create_group(&dev->kobj, &blk_trace_attr_group);
1876 void blk_trace_remove_sysfs(struct device *dev)
1878 sysfs_remove_group(&dev->kobj, &blk_trace_attr_group);
1881 #endif /* CONFIG_BLK_DEV_IO_TRACE */
1883 #ifdef CONFIG_EVENT_TRACING
1886 * blk_fill_rwbs - Fill the buffer rwbs by mapping op to character string.
1887 * @rwbs: buffer to be filled
1888 * @op: REQ_OP_XXX for the tracepoint
1891 * Maps the REQ_OP_XXX to character and fills the buffer provided by the
1892 * caller with resulting string.
1895 void blk_fill_rwbs(char *rwbs, unsigned int op)
1899 if (op & REQ_PREFLUSH)
1902 switch (op & REQ_OP_MASK) {
1906 case REQ_OP_DISCARD:
1909 case REQ_OP_SECURE_ERASE:
1925 if (op & REQ_RAHEAD)
1934 EXPORT_SYMBOL_GPL(blk_fill_rwbs);
1936 #endif /* CONFIG_EVENT_TRACING */