2 * Copyright (C) 2006 Jens Axboe <axboe@kernel.dk>
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
13 * You should have received a copy of the GNU General Public License
14 * along with this program; if not, write to the Free Software
15 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
18 #include <linux/kernel.h>
19 #include <linux/blkdev.h>
20 #include <linux/blktrace_api.h>
21 #include <linux/percpu.h>
22 #include <linux/init.h>
23 #include <linux/mutex.h>
24 #include <linux/debugfs.h>
25 #include <linux/time.h>
26 #include <trace/block.h>
27 #include <linux/uaccess.h>
28 #include "trace_output.h"
30 static unsigned int blktrace_seq __read_mostly
= 1;
32 static struct trace_array
*blk_tr
;
33 static bool blk_tracer_enabled __read_mostly
;
35 /* Select an alternative, minimalistic output than the original one */
36 #define TRACE_BLK_OPT_CLASSIC 0x1
38 static struct tracer_opt blk_tracer_opts
[] = {
39 /* Default disable the minimalistic output */
40 { TRACER_OPT(blk_classic
, TRACE_BLK_OPT_CLASSIC
) },
44 static struct tracer_flags blk_tracer_flags
= {
46 .opts
= blk_tracer_opts
,
49 /* Global reference count of probes */
50 static atomic_t blk_probes_ref
= ATOMIC_INIT(0);
52 static void blk_register_tracepoints(void);
53 static void blk_unregister_tracepoints(void);
56 * Send out a notify message.
58 static void trace_note(struct blk_trace
*bt
, pid_t pid
, int action
,
59 const void *data
, size_t len
)
61 struct blk_io_trace
*t
;
66 t
= relay_reserve(bt
->rchan
, sizeof(*t
) + len
);
68 const int cpu
= smp_processor_id();
70 t
->magic
= BLK_IO_TRACE_MAGIC
| BLK_IO_TRACE_VERSION
;
71 t
->time
= ktime_to_ns(ktime_get());
77 memcpy((void *) t
+ sizeof(*t
), data
, len
);
82 * Send out a notify for this process, if we haven't done so since a trace
85 static void trace_note_tsk(struct blk_trace
*bt
, struct task_struct
*tsk
)
87 tsk
->btrace_seq
= blktrace_seq
;
88 trace_note(bt
, tsk
->pid
, BLK_TN_PROCESS
, tsk
->comm
, sizeof(tsk
->comm
));
91 static void trace_note_time(struct blk_trace
*bt
)
98 words
[0] = now
.tv_sec
;
99 words
[1] = now
.tv_nsec
;
101 local_irq_save(flags
);
102 trace_note(bt
, 0, BLK_TN_TIMESTAMP
, words
, sizeof(words
));
103 local_irq_restore(flags
);
106 void __trace_note_message(struct blk_trace
*bt
, const char *fmt
, ...)
113 if (blk_tracer_enabled
) {
115 ftrace_vprintk(fmt
, args
);
123 local_irq_save(flags
);
124 buf
= per_cpu_ptr(bt
->msg_data
, smp_processor_id());
126 n
= vscnprintf(buf
, BLK_TN_MAX_MSG
, fmt
, args
);
129 trace_note(bt
, 0, BLK_TN_MESSAGE
, buf
, n
);
130 local_irq_restore(flags
);
132 EXPORT_SYMBOL_GPL(__trace_note_message
);
134 static int act_log_check(struct blk_trace
*bt
, u32 what
, sector_t sector
,
137 if (((bt
->act_mask
<< BLK_TC_SHIFT
) & what
) == 0)
139 if (sector
< bt
->start_lba
|| sector
> bt
->end_lba
)
141 if (bt
->pid
&& pid
!= bt
->pid
)
148 * Data direction bit lookup
150 static const u32 ddir_act
[2] = { BLK_TC_ACT(BLK_TC_READ
),
151 BLK_TC_ACT(BLK_TC_WRITE
) };
153 /* The ilog2() calls fall out because they're constant */
154 #define MASK_TC_BIT(rw, __name) ((rw & (1 << BIO_RW_ ## __name)) << \
155 (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - BIO_RW_ ## __name))
158 * The worker for the various blk_add_trace*() types. Fills out a
159 * blk_io_trace structure and places it in a per-cpu subbuffer.
161 static void __blk_add_trace(struct blk_trace
*bt
, sector_t sector
, int bytes
,
162 int rw
, u32 what
, int error
, int pdu_len
, void *pdu_data
)
164 struct task_struct
*tsk
= current
;
165 struct ring_buffer_event
*event
= NULL
;
166 struct blk_io_trace
*t
;
167 unsigned long flags
= 0;
168 unsigned long *sequence
;
172 if (unlikely(bt
->trace_state
!= Blktrace_running
&&
173 !blk_tracer_enabled
))
176 what
|= ddir_act
[rw
& WRITE
];
177 what
|= MASK_TC_BIT(rw
, BARRIER
);
178 what
|= MASK_TC_BIT(rw
, SYNCIO
);
179 what
|= MASK_TC_BIT(rw
, AHEAD
);
180 what
|= MASK_TC_BIT(rw
, META
);
181 what
|= MASK_TC_BIT(rw
, DISCARD
);
184 if (unlikely(act_log_check(bt
, what
, sector
, pid
)))
186 cpu
= raw_smp_processor_id();
188 if (blk_tracer_enabled
) {
189 tracing_record_cmdline(current
);
191 pc
= preempt_count();
192 event
= trace_buffer_lock_reserve(blk_tr
, TRACE_BLK
,
193 sizeof(*t
) + pdu_len
,
197 t
= ring_buffer_event_data(event
);
202 * A word about the locking here - we disable interrupts to reserve
203 * some space in the relay per-cpu buffer, to prevent an irq
204 * from coming in and stepping on our toes.
206 local_irq_save(flags
);
208 if (unlikely(tsk
->btrace_seq
!= blktrace_seq
))
209 trace_note_tsk(bt
, tsk
);
211 t
= relay_reserve(bt
->rchan
, sizeof(*t
) + pdu_len
);
213 sequence
= per_cpu_ptr(bt
->sequence
, cpu
);
215 t
->magic
= BLK_IO_TRACE_MAGIC
| BLK_IO_TRACE_VERSION
;
216 t
->sequence
= ++(*sequence
);
217 t
->time
= ktime_to_ns(ktime_get());
220 * These two are not needed in ftrace as they are in the
221 * generic trace_entry, filled by tracing_generic_entry_update,
222 * but for the trace_event->bin() synthesizer benefit we do it
233 t
->pdu_len
= pdu_len
;
236 memcpy((void *) t
+ sizeof(*t
), pdu_data
, pdu_len
);
238 if (blk_tracer_enabled
) {
239 trace_buffer_unlock_commit(blk_tr
, event
, 0, pc
);
244 local_irq_restore(flags
);
247 static struct dentry
*blk_tree_root
;
248 static DEFINE_MUTEX(blk_tree_mutex
);
250 static void blk_trace_cleanup(struct blk_trace
*bt
)
252 debugfs_remove(bt
->msg_file
);
253 debugfs_remove(bt
->dropped_file
);
254 relay_close(bt
->rchan
);
255 free_percpu(bt
->sequence
);
256 free_percpu(bt
->msg_data
);
258 if (atomic_dec_and_test(&blk_probes_ref
))
259 blk_unregister_tracepoints();
262 int blk_trace_remove(struct request_queue
*q
)
264 struct blk_trace
*bt
;
266 bt
= xchg(&q
->blk_trace
, NULL
);
270 if (bt
->trace_state
!= Blktrace_running
)
271 blk_trace_cleanup(bt
);
275 EXPORT_SYMBOL_GPL(blk_trace_remove
);
277 static int blk_dropped_open(struct inode
*inode
, struct file
*filp
)
279 filp
->private_data
= inode
->i_private
;
284 static ssize_t
blk_dropped_read(struct file
*filp
, char __user
*buffer
,
285 size_t count
, loff_t
*ppos
)
287 struct blk_trace
*bt
= filp
->private_data
;
290 snprintf(buf
, sizeof(buf
), "%u\n", atomic_read(&bt
->dropped
));
292 return simple_read_from_buffer(buffer
, count
, ppos
, buf
, strlen(buf
));
295 static const struct file_operations blk_dropped_fops
= {
296 .owner
= THIS_MODULE
,
297 .open
= blk_dropped_open
,
298 .read
= blk_dropped_read
,
301 static int blk_msg_open(struct inode
*inode
, struct file
*filp
)
303 filp
->private_data
= inode
->i_private
;
308 static ssize_t
blk_msg_write(struct file
*filp
, const char __user
*buffer
,
309 size_t count
, loff_t
*ppos
)
312 struct blk_trace
*bt
;
314 if (count
> BLK_TN_MAX_MSG
)
317 msg
= kmalloc(count
, GFP_KERNEL
);
321 if (copy_from_user(msg
, buffer
, count
)) {
326 bt
= filp
->private_data
;
327 __trace_note_message(bt
, "%s", msg
);
333 static const struct file_operations blk_msg_fops
= {
334 .owner
= THIS_MODULE
,
335 .open
= blk_msg_open
,
336 .write
= blk_msg_write
,
340 * Keep track of how many times we encountered a full subbuffer, to aid
341 * the user space app in telling how many lost events there were.
343 static int blk_subbuf_start_callback(struct rchan_buf
*buf
, void *subbuf
,
344 void *prev_subbuf
, size_t prev_padding
)
346 struct blk_trace
*bt
;
348 if (!relay_buf_full(buf
))
351 bt
= buf
->chan
->private_data
;
352 atomic_inc(&bt
->dropped
);
356 static int blk_remove_buf_file_callback(struct dentry
*dentry
)
358 struct dentry
*parent
= dentry
->d_parent
;
359 debugfs_remove(dentry
);
362 * this will fail for all but the last file, but that is ok. what we
363 * care about is the top level buts->name directory going away, when
364 * the last trace file is gone. Then we don't have to rmdir() that
365 * manually on trace stop, so it nicely solves the issue with
366 * force killing of running traces.
369 debugfs_remove(parent
);
373 static struct dentry
*blk_create_buf_file_callback(const char *filename
,
374 struct dentry
*parent
,
376 struct rchan_buf
*buf
,
379 return debugfs_create_file(filename
, mode
, parent
, buf
,
380 &relay_file_operations
);
383 static struct rchan_callbacks blk_relay_callbacks
= {
384 .subbuf_start
= blk_subbuf_start_callback
,
385 .create_buf_file
= blk_create_buf_file_callback
,
386 .remove_buf_file
= blk_remove_buf_file_callback
,
390 * Setup everything required to start tracing
392 int do_blk_trace_setup(struct request_queue
*q
, char *name
, dev_t dev
,
393 struct blk_user_trace_setup
*buts
)
395 struct blk_trace
*old_bt
, *bt
= NULL
;
396 struct dentry
*dir
= NULL
;
399 if (!buts
->buf_size
|| !buts
->buf_nr
)
402 strncpy(buts
->name
, name
, BLKTRACE_BDEV_SIZE
);
403 buts
->name
[BLKTRACE_BDEV_SIZE
- 1] = '\0';
406 * some device names have larger paths - convert the slashes
407 * to underscores for this to work as expected
409 for (i
= 0; i
< strlen(buts
->name
); i
++)
410 if (buts
->name
[i
] == '/')
414 bt
= kzalloc(sizeof(*bt
), GFP_KERNEL
);
418 bt
->sequence
= alloc_percpu(unsigned long);
422 bt
->msg_data
= __alloc_percpu(BLK_TN_MAX_MSG
, __alignof__(char));
428 mutex_lock(&blk_tree_mutex
);
429 if (!blk_tree_root
) {
430 blk_tree_root
= debugfs_create_dir("block", NULL
);
431 if (!blk_tree_root
) {
432 mutex_unlock(&blk_tree_mutex
);
436 mutex_unlock(&blk_tree_mutex
);
438 dir
= debugfs_create_dir(buts
->name
, blk_tree_root
);
445 atomic_set(&bt
->dropped
, 0);
448 bt
->dropped_file
= debugfs_create_file("dropped", 0444, dir
, bt
,
450 if (!bt
->dropped_file
)
453 bt
->msg_file
= debugfs_create_file("msg", 0222, dir
, bt
, &blk_msg_fops
);
457 bt
->rchan
= relay_open("trace", dir
, buts
->buf_size
,
458 buts
->buf_nr
, &blk_relay_callbacks
, bt
);
462 bt
->act_mask
= buts
->act_mask
;
464 bt
->act_mask
= (u16
) -1;
466 bt
->start_lba
= buts
->start_lba
;
467 bt
->end_lba
= buts
->end_lba
;
472 bt
->trace_state
= Blktrace_setup
;
475 old_bt
= xchg(&q
->blk_trace
, bt
);
477 (void) xchg(&q
->blk_trace
, old_bt
);
481 if (atomic_add_return(1, &blk_probes_ref
) == 1)
482 blk_register_tracepoints();
488 debugfs_remove(bt
->msg_file
);
489 if (bt
->dropped_file
)
490 debugfs_remove(bt
->dropped_file
);
491 free_percpu(bt
->sequence
);
492 free_percpu(bt
->msg_data
);
494 relay_close(bt
->rchan
);
500 int blk_trace_setup(struct request_queue
*q
, char *name
, dev_t dev
,
503 struct blk_user_trace_setup buts
;
506 ret
= copy_from_user(&buts
, arg
, sizeof(buts
));
510 ret
= do_blk_trace_setup(q
, name
, dev
, &buts
);
514 if (copy_to_user(arg
, &buts
, sizeof(buts
)))
519 EXPORT_SYMBOL_GPL(blk_trace_setup
);
521 int blk_trace_startstop(struct request_queue
*q
, int start
)
524 struct blk_trace
*bt
= q
->blk_trace
;
530 * For starting a trace, we can transition from a setup or stopped
531 * trace. For stopping a trace, the state must be running
535 if (bt
->trace_state
== Blktrace_setup
||
536 bt
->trace_state
== Blktrace_stopped
) {
539 bt
->trace_state
= Blktrace_running
;
545 if (bt
->trace_state
== Blktrace_running
) {
546 bt
->trace_state
= Blktrace_stopped
;
547 relay_flush(bt
->rchan
);
554 EXPORT_SYMBOL_GPL(blk_trace_startstop
);
557 * blk_trace_ioctl: - handle the ioctls associated with tracing
558 * @bdev: the block device
559 * @cmd: the ioctl cmd
560 * @arg: the argument data, if any
563 int blk_trace_ioctl(struct block_device
*bdev
, unsigned cmd
, char __user
*arg
)
565 struct request_queue
*q
;
567 char b
[BDEVNAME_SIZE
];
569 q
= bdev_get_queue(bdev
);
573 mutex_lock(&bdev
->bd_mutex
);
578 ret
= blk_trace_setup(q
, b
, bdev
->bd_dev
, arg
);
583 ret
= blk_trace_startstop(q
, start
);
585 case BLKTRACETEARDOWN
:
586 ret
= blk_trace_remove(q
);
593 mutex_unlock(&bdev
->bd_mutex
);
598 * blk_trace_shutdown: - stop and cleanup trace structures
599 * @q: the request queue associated with the device
602 void blk_trace_shutdown(struct request_queue
*q
)
605 blk_trace_startstop(q
, 0);
615 * blk_add_trace_rq - Add a trace for a request oriented action
616 * @q: queue the io is for
617 * @rq: the source request
621 * Records an action against a request. Will log the bio offset + size.
624 static void blk_add_trace_rq(struct request_queue
*q
, struct request
*rq
,
627 struct blk_trace
*bt
= q
->blk_trace
;
628 int rw
= rq
->cmd_flags
& 0x03;
633 if (blk_discard_rq(rq
))
634 rw
|= (1 << BIO_RW_DISCARD
);
636 if (blk_pc_request(rq
)) {
637 what
|= BLK_TC_ACT(BLK_TC_PC
);
638 __blk_add_trace(bt
, 0, rq
->data_len
, rw
, what
, rq
->errors
,
639 sizeof(rq
->cmd
), rq
->cmd
);
641 what
|= BLK_TC_ACT(BLK_TC_FS
);
642 __blk_add_trace(bt
, rq
->hard_sector
, rq
->hard_nr_sectors
<< 9,
643 rw
, what
, rq
->errors
, 0, NULL
);
647 static void blk_add_trace_rq_abort(struct request_queue
*q
, struct request
*rq
)
649 blk_add_trace_rq(q
, rq
, BLK_TA_ABORT
);
652 static void blk_add_trace_rq_insert(struct request_queue
*q
, struct request
*rq
)
654 blk_add_trace_rq(q
, rq
, BLK_TA_INSERT
);
657 static void blk_add_trace_rq_issue(struct request_queue
*q
, struct request
*rq
)
659 blk_add_trace_rq(q
, rq
, BLK_TA_ISSUE
);
662 static void blk_add_trace_rq_requeue(struct request_queue
*q
,
665 blk_add_trace_rq(q
, rq
, BLK_TA_REQUEUE
);
668 static void blk_add_trace_rq_complete(struct request_queue
*q
,
671 blk_add_trace_rq(q
, rq
, BLK_TA_COMPLETE
);
675 * blk_add_trace_bio - Add a trace for a bio oriented action
676 * @q: queue the io is for
677 * @bio: the source bio
681 * Records an action against a bio. Will log the bio offset + size.
684 static void blk_add_trace_bio(struct request_queue
*q
, struct bio
*bio
,
687 struct blk_trace
*bt
= q
->blk_trace
;
692 __blk_add_trace(bt
, bio
->bi_sector
, bio
->bi_size
, bio
->bi_rw
, what
,
693 !bio_flagged(bio
, BIO_UPTODATE
), 0, NULL
);
696 static void blk_add_trace_bio_bounce(struct request_queue
*q
, struct bio
*bio
)
698 blk_add_trace_bio(q
, bio
, BLK_TA_BOUNCE
);
701 static void blk_add_trace_bio_complete(struct request_queue
*q
, struct bio
*bio
)
703 blk_add_trace_bio(q
, bio
, BLK_TA_COMPLETE
);
706 static void blk_add_trace_bio_backmerge(struct request_queue
*q
,
709 blk_add_trace_bio(q
, bio
, BLK_TA_BACKMERGE
);
712 static void blk_add_trace_bio_frontmerge(struct request_queue
*q
,
715 blk_add_trace_bio(q
, bio
, BLK_TA_FRONTMERGE
);
718 static void blk_add_trace_bio_queue(struct request_queue
*q
, struct bio
*bio
)
720 blk_add_trace_bio(q
, bio
, BLK_TA_QUEUE
);
723 static void blk_add_trace_getrq(struct request_queue
*q
,
724 struct bio
*bio
, int rw
)
727 blk_add_trace_bio(q
, bio
, BLK_TA_GETRQ
);
729 struct blk_trace
*bt
= q
->blk_trace
;
732 __blk_add_trace(bt
, 0, 0, rw
, BLK_TA_GETRQ
, 0, 0, NULL
);
737 static void blk_add_trace_sleeprq(struct request_queue
*q
,
738 struct bio
*bio
, int rw
)
741 blk_add_trace_bio(q
, bio
, BLK_TA_SLEEPRQ
);
743 struct blk_trace
*bt
= q
->blk_trace
;
746 __blk_add_trace(bt
, 0, 0, rw
, BLK_TA_SLEEPRQ
,
751 static void blk_add_trace_plug(struct request_queue
*q
)
753 struct blk_trace
*bt
= q
->blk_trace
;
756 __blk_add_trace(bt
, 0, 0, 0, BLK_TA_PLUG
, 0, 0, NULL
);
759 static void blk_add_trace_unplug_io(struct request_queue
*q
)
761 struct blk_trace
*bt
= q
->blk_trace
;
764 unsigned int pdu
= q
->rq
.count
[READ
] + q
->rq
.count
[WRITE
];
765 __be64 rpdu
= cpu_to_be64(pdu
);
767 __blk_add_trace(bt
, 0, 0, 0, BLK_TA_UNPLUG_IO
, 0,
768 sizeof(rpdu
), &rpdu
);
772 static void blk_add_trace_unplug_timer(struct request_queue
*q
)
774 struct blk_trace
*bt
= q
->blk_trace
;
777 unsigned int pdu
= q
->rq
.count
[READ
] + q
->rq
.count
[WRITE
];
778 __be64 rpdu
= cpu_to_be64(pdu
);
780 __blk_add_trace(bt
, 0, 0, 0, BLK_TA_UNPLUG_TIMER
, 0,
781 sizeof(rpdu
), &rpdu
);
785 static void blk_add_trace_split(struct request_queue
*q
, struct bio
*bio
,
788 struct blk_trace
*bt
= q
->blk_trace
;
791 __be64 rpdu
= cpu_to_be64(pdu
);
793 __blk_add_trace(bt
, bio
->bi_sector
, bio
->bi_size
, bio
->bi_rw
,
794 BLK_TA_SPLIT
, !bio_flagged(bio
, BIO_UPTODATE
),
795 sizeof(rpdu
), &rpdu
);
800 * blk_add_trace_remap - Add a trace for a remap operation
801 * @q: queue the io is for
802 * @bio: the source bio
803 * @dev: target device
804 * @from: source sector
808 * Device mapper or raid target sometimes need to split a bio because
809 * it spans a stripe (or similar). Add a trace for that action.
812 static void blk_add_trace_remap(struct request_queue
*q
, struct bio
*bio
,
813 dev_t dev
, sector_t from
, sector_t to
)
815 struct blk_trace
*bt
= q
->blk_trace
;
816 struct blk_io_trace_remap r
;
821 r
.device
= cpu_to_be32(dev
);
822 r
.device_from
= cpu_to_be32(bio
->bi_bdev
->bd_dev
);
823 r
.sector
= cpu_to_be64(to
);
825 __blk_add_trace(bt
, from
, bio
->bi_size
, bio
->bi_rw
, BLK_TA_REMAP
,
826 !bio_flagged(bio
, BIO_UPTODATE
), sizeof(r
), &r
);
830 * blk_add_driver_data - Add binary message with driver-specific data
831 * @q: queue the io is for
833 * @data: driver-specific data
834 * @len: length of driver-specific data
837 * Some drivers might want to write driver-specific data per request.
840 void blk_add_driver_data(struct request_queue
*q
,
842 void *data
, size_t len
)
844 struct blk_trace
*bt
= q
->blk_trace
;
849 if (blk_pc_request(rq
))
850 __blk_add_trace(bt
, 0, rq
->data_len
, 0, BLK_TA_DRV_DATA
,
851 rq
->errors
, len
, data
);
853 __blk_add_trace(bt
, rq
->hard_sector
, rq
->hard_nr_sectors
<< 9,
854 0, BLK_TA_DRV_DATA
, rq
->errors
, len
, data
);
856 EXPORT_SYMBOL_GPL(blk_add_driver_data
);
858 static void blk_register_tracepoints(void)
862 ret
= register_trace_block_rq_abort(blk_add_trace_rq_abort
);
864 ret
= register_trace_block_rq_insert(blk_add_trace_rq_insert
);
866 ret
= register_trace_block_rq_issue(blk_add_trace_rq_issue
);
868 ret
= register_trace_block_rq_requeue(blk_add_trace_rq_requeue
);
870 ret
= register_trace_block_rq_complete(blk_add_trace_rq_complete
);
872 ret
= register_trace_block_bio_bounce(blk_add_trace_bio_bounce
);
874 ret
= register_trace_block_bio_complete(blk_add_trace_bio_complete
);
876 ret
= register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge
);
878 ret
= register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge
);
880 ret
= register_trace_block_bio_queue(blk_add_trace_bio_queue
);
882 ret
= register_trace_block_getrq(blk_add_trace_getrq
);
884 ret
= register_trace_block_sleeprq(blk_add_trace_sleeprq
);
886 ret
= register_trace_block_plug(blk_add_trace_plug
);
888 ret
= register_trace_block_unplug_timer(blk_add_trace_unplug_timer
);
890 ret
= register_trace_block_unplug_io(blk_add_trace_unplug_io
);
892 ret
= register_trace_block_split(blk_add_trace_split
);
894 ret
= register_trace_block_remap(blk_add_trace_remap
);
898 static void blk_unregister_tracepoints(void)
900 unregister_trace_block_remap(blk_add_trace_remap
);
901 unregister_trace_block_split(blk_add_trace_split
);
902 unregister_trace_block_unplug_io(blk_add_trace_unplug_io
);
903 unregister_trace_block_unplug_timer(blk_add_trace_unplug_timer
);
904 unregister_trace_block_plug(blk_add_trace_plug
);
905 unregister_trace_block_sleeprq(blk_add_trace_sleeprq
);
906 unregister_trace_block_getrq(blk_add_trace_getrq
);
907 unregister_trace_block_bio_queue(blk_add_trace_bio_queue
);
908 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge
);
909 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge
);
910 unregister_trace_block_bio_complete(blk_add_trace_bio_complete
);
911 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce
);
912 unregister_trace_block_rq_complete(blk_add_trace_rq_complete
);
913 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue
);
914 unregister_trace_block_rq_issue(blk_add_trace_rq_issue
);
915 unregister_trace_block_rq_insert(blk_add_trace_rq_insert
);
916 unregister_trace_block_rq_abort(blk_add_trace_rq_abort
);
918 tracepoint_synchronize_unregister();
922 * struct blk_io_tracer formatting routines
925 static void fill_rwbs(char *rwbs
, const struct blk_io_trace
*t
)
928 int tc
= t
->action
>> BLK_TC_SHIFT
;
930 if (tc
& BLK_TC_DISCARD
)
932 else if (tc
& BLK_TC_WRITE
)
939 if (tc
& BLK_TC_AHEAD
)
941 if (tc
& BLK_TC_BARRIER
)
943 if (tc
& BLK_TC_SYNC
)
945 if (tc
& BLK_TC_META
)
952 const struct blk_io_trace
*te_blk_io_trace(const struct trace_entry
*ent
)
954 return (const struct blk_io_trace
*)ent
;
957 static inline const void *pdu_start(const struct trace_entry
*ent
)
959 return te_blk_io_trace(ent
) + 1;
962 static inline u32
t_sec(const struct trace_entry
*ent
)
964 return te_blk_io_trace(ent
)->bytes
>> 9;
967 static inline unsigned long long t_sector(const struct trace_entry
*ent
)
969 return te_blk_io_trace(ent
)->sector
;
972 static inline __u16
t_error(const struct trace_entry
*ent
)
974 return te_blk_io_trace(ent
)->error
;
977 static __u64
get_pdu_int(const struct trace_entry
*ent
)
979 const __u64
*val
= pdu_start(ent
);
980 return be64_to_cpu(*val
);
983 static void get_pdu_remap(const struct trace_entry
*ent
,
984 struct blk_io_trace_remap
*r
)
986 const struct blk_io_trace_remap
*__r
= pdu_start(ent
);
987 __u64 sector
= __r
->sector
;
989 r
->device
= be32_to_cpu(__r
->device
);
990 r
->device_from
= be32_to_cpu(__r
->device_from
);
991 r
->sector
= be64_to_cpu(sector
);
994 static int blk_log_action_iter(struct trace_iterator
*iter
, const char *act
)
997 unsigned long long ts
= iter
->ts
;
998 unsigned long nsec_rem
= do_div(ts
, NSEC_PER_SEC
);
999 unsigned secs
= (unsigned long)ts
;
1000 const struct trace_entry
*ent
= iter
->ent
;
1001 const struct blk_io_trace
*t
= (const struct blk_io_trace
*)ent
;
1005 return trace_seq_printf(&iter
->seq
,
1006 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
1007 MAJOR(t
->device
), MINOR(t
->device
), iter
->cpu
,
1008 secs
, nsec_rem
, ent
->pid
, act
, rwbs
);
1011 static int blk_log_action_seq(struct trace_seq
*s
, const struct blk_io_trace
*t
,
1016 return trace_seq_printf(s
, "%3d,%-3d %2s %3s ",
1017 MAJOR(t
->device
), MINOR(t
->device
), act
, rwbs
);
1020 static int blk_log_generic(struct trace_seq
*s
, const struct trace_entry
*ent
)
1022 char cmd
[TASK_COMM_LEN
];
1024 trace_find_cmdline(ent
->pid
, cmd
);
1027 return trace_seq_printf(s
, "%llu + %u [%s]\n",
1028 t_sector(ent
), t_sec(ent
), cmd
);
1029 return trace_seq_printf(s
, "[%s]\n", cmd
);
1032 static int blk_log_with_error(struct trace_seq
*s
,
1033 const struct trace_entry
*ent
)
1036 return trace_seq_printf(s
, "%llu + %u [%d]\n", t_sector(ent
),
1037 t_sec(ent
), t_error(ent
));
1038 return trace_seq_printf(s
, "%llu [%d]\n", t_sector(ent
), t_error(ent
));
1041 static int blk_log_remap(struct trace_seq
*s
, const struct trace_entry
*ent
)
1043 struct blk_io_trace_remap r
= { .device
= 0, };
1045 get_pdu_remap(ent
, &r
);
1046 return trace_seq_printf(s
, "%llu + %u <- (%d,%d) %llu\n",
1048 t_sec(ent
), MAJOR(r
.device
), MINOR(r
.device
),
1049 (unsigned long long)r
.sector
);
1052 static int blk_log_plug(struct trace_seq
*s
, const struct trace_entry
*ent
)
1054 char cmd
[TASK_COMM_LEN
];
1056 trace_find_cmdline(ent
->pid
, cmd
);
1058 return trace_seq_printf(s
, "[%s]\n", cmd
);
1061 static int blk_log_unplug(struct trace_seq
*s
, const struct trace_entry
*ent
)
1063 char cmd
[TASK_COMM_LEN
];
1065 trace_find_cmdline(ent
->pid
, cmd
);
1067 return trace_seq_printf(s
, "[%s] %llu\n", cmd
, get_pdu_int(ent
));
1070 static int blk_log_split(struct trace_seq
*s
, const struct trace_entry
*ent
)
1072 char cmd
[TASK_COMM_LEN
];
1074 trace_find_cmdline(ent
->pid
, cmd
);
1076 return trace_seq_printf(s
, "%llu / %llu [%s]\n", t_sector(ent
),
1077 get_pdu_int(ent
), cmd
);
1081 * struct tracer operations
1084 static void blk_tracer_print_header(struct seq_file
*m
)
1086 if (!(blk_tracer_flags
.val
& TRACE_BLK_OPT_CLASSIC
))
1088 seq_puts(m
, "# DEV CPU TIMESTAMP PID ACT FLG\n"
1092 static void blk_tracer_start(struct trace_array
*tr
)
1094 if (atomic_add_return(1, &blk_probes_ref
) == 1)
1095 blk_register_tracepoints();
1096 trace_flags
&= ~TRACE_ITER_CONTEXT_INFO
;
1099 static int blk_tracer_init(struct trace_array
*tr
)
1102 blk_tracer_start(tr
);
1103 blk_tracer_enabled
= true;
1107 static void blk_tracer_stop(struct trace_array
*tr
)
1109 trace_flags
|= TRACE_ITER_CONTEXT_INFO
;
1110 if (atomic_dec_and_test(&blk_probes_ref
))
1111 blk_unregister_tracepoints();
1114 static void blk_tracer_reset(struct trace_array
*tr
)
1116 if (!atomic_read(&blk_probes_ref
))
1119 blk_tracer_enabled
= false;
1120 blk_tracer_stop(tr
);
1123 static const struct {
1125 int (*print
)(struct trace_seq
*s
, const struct trace_entry
*ent
);
1127 [__BLK_TA_QUEUE
] = {{ "Q", "queue" }, blk_log_generic
},
1128 [__BLK_TA_BACKMERGE
] = {{ "M", "backmerge" }, blk_log_generic
},
1129 [__BLK_TA_FRONTMERGE
] = {{ "F", "frontmerge" }, blk_log_generic
},
1130 [__BLK_TA_GETRQ
] = {{ "G", "getrq" }, blk_log_generic
},
1131 [__BLK_TA_SLEEPRQ
] = {{ "S", "sleeprq" }, blk_log_generic
},
1132 [__BLK_TA_REQUEUE
] = {{ "R", "requeue" }, blk_log_with_error
},
1133 [__BLK_TA_ISSUE
] = {{ "D", "issue" }, blk_log_generic
},
1134 [__BLK_TA_COMPLETE
] = {{ "C", "complete" }, blk_log_with_error
},
1135 [__BLK_TA_PLUG
] = {{ "P", "plug" }, blk_log_plug
},
1136 [__BLK_TA_UNPLUG_IO
] = {{ "U", "unplug_io" }, blk_log_unplug
},
1137 [__BLK_TA_UNPLUG_TIMER
] = {{ "UT", "unplug_timer" }, blk_log_unplug
},
1138 [__BLK_TA_INSERT
] = {{ "I", "insert" }, blk_log_generic
},
1139 [__BLK_TA_SPLIT
] = {{ "X", "split" }, blk_log_split
},
1140 [__BLK_TA_BOUNCE
] = {{ "B", "bounce" }, blk_log_generic
},
1141 [__BLK_TA_REMAP
] = {{ "A", "remap" }, blk_log_remap
},
1144 static enum print_line_t
blk_trace_event_print(struct trace_iterator
*iter
,
1147 struct trace_seq
*s
= &iter
->seq
;
1148 const struct blk_io_trace
*t
= (struct blk_io_trace
*)iter
->ent
;
1149 const u16 what
= t
->action
& ((1 << BLK_TC_SHIFT
) - 1);
1152 if (!trace_print_context(iter
))
1153 return TRACE_TYPE_PARTIAL_LINE
;
1155 if (unlikely(what
== 0 || what
>= ARRAY_SIZE(what2act
)))
1156 ret
= trace_seq_printf(s
, "Bad pc action %x\n", what
);
1158 const bool long_act
= !!(trace_flags
& TRACE_ITER_VERBOSE
);
1159 ret
= blk_log_action_seq(s
, t
, what2act
[what
].act
[long_act
]);
1161 ret
= what2act
[what
].print(s
, iter
->ent
);
1164 return ret
? TRACE_TYPE_HANDLED
: TRACE_TYPE_PARTIAL_LINE
;
1167 static int blk_trace_synthesize_old_trace(struct trace_iterator
*iter
)
1169 struct trace_seq
*s
= &iter
->seq
;
1170 struct blk_io_trace
*t
= (struct blk_io_trace
*)iter
->ent
;
1171 const int offset
= offsetof(struct blk_io_trace
, sector
);
1172 struct blk_io_trace old
= {
1173 .magic
= BLK_IO_TRACE_MAGIC
| BLK_IO_TRACE_VERSION
,
1177 if (!trace_seq_putmem(s
, &old
, offset
))
1179 return trace_seq_putmem(s
, &t
->sector
,
1180 sizeof(old
) - offset
+ t
->pdu_len
);
1183 static enum print_line_t
1184 blk_trace_event_print_binary(struct trace_iterator
*iter
, int flags
)
1186 return blk_trace_synthesize_old_trace(iter
) ?
1187 TRACE_TYPE_HANDLED
: TRACE_TYPE_PARTIAL_LINE
;
1190 static enum print_line_t
blk_tracer_print_line(struct trace_iterator
*iter
)
1192 const struct blk_io_trace
*t
;
1196 if (!(blk_tracer_flags
.val
& TRACE_BLK_OPT_CLASSIC
))
1197 return TRACE_TYPE_UNHANDLED
;
1199 t
= (const struct blk_io_trace
*)iter
->ent
;
1200 what
= t
->action
& ((1 << BLK_TC_SHIFT
) - 1);
1202 if (unlikely(what
== 0 || what
>= ARRAY_SIZE(what2act
)))
1203 ret
= trace_seq_printf(&iter
->seq
, "Bad pc action %x\n", what
);
1205 const bool long_act
= !!(trace_flags
& TRACE_ITER_VERBOSE
);
1206 ret
= blk_log_action_iter(iter
, what2act
[what
].act
[long_act
]);
1208 ret
= what2act
[what
].print(&iter
->seq
, iter
->ent
);
1211 return ret
? TRACE_TYPE_HANDLED
: TRACE_TYPE_PARTIAL_LINE
;
1214 static struct tracer blk_tracer __read_mostly
= {
1216 .init
= blk_tracer_init
,
1217 .reset
= blk_tracer_reset
,
1218 .start
= blk_tracer_start
,
1219 .stop
= blk_tracer_stop
,
1220 .print_header
= blk_tracer_print_header
,
1221 .print_line
= blk_tracer_print_line
,
1222 .flags
= &blk_tracer_flags
,
1225 static struct trace_event trace_blk_event
= {
1227 .trace
= blk_trace_event_print
,
1228 .binary
= blk_trace_event_print_binary
,
1231 static int __init
init_blk_tracer(void)
1233 if (!register_ftrace_event(&trace_blk_event
)) {
1234 pr_warning("Warning: could not register block events\n");
1238 if (register_tracer(&blk_tracer
) != 0) {
1239 pr_warning("Warning: could not register the block tracer\n");
1240 unregister_ftrace_event(&trace_blk_event
);
1247 device_initcall(init_blk_tracer
);
1249 static int blk_trace_remove_queue(struct request_queue
*q
)
1251 struct blk_trace
*bt
;
1253 bt
= xchg(&q
->blk_trace
, NULL
);
1262 * Setup everything required to start tracing
1264 static int blk_trace_setup_queue(struct request_queue
*q
, dev_t dev
)
1266 struct blk_trace
*old_bt
, *bt
= NULL
;
1268 bt
= kzalloc(sizeof(*bt
), GFP_KERNEL
);
1273 bt
->act_mask
= (u16
)-1;
1274 bt
->end_lba
= -1ULL;
1276 old_bt
= xchg(&q
->blk_trace
, bt
);
1277 if (old_bt
!= NULL
) {
1278 (void)xchg(&q
->blk_trace
, old_bt
);
1287 * sysfs interface to enable and configure tracing
1290 static ssize_t
sysfs_blk_trace_attr_show(struct device
*dev
,
1291 struct device_attribute
*attr
,
1293 static ssize_t
sysfs_blk_trace_attr_store(struct device
*dev
,
1294 struct device_attribute
*attr
,
1295 const char *buf
, size_t count
);
1296 #define BLK_TRACE_DEVICE_ATTR(_name) \
1297 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
1298 sysfs_blk_trace_attr_show, \
1299 sysfs_blk_trace_attr_store)
1301 static BLK_TRACE_DEVICE_ATTR(enable
);
1302 static BLK_TRACE_DEVICE_ATTR(act_mask
);
1303 static BLK_TRACE_DEVICE_ATTR(pid
);
1304 static BLK_TRACE_DEVICE_ATTR(start_lba
);
1305 static BLK_TRACE_DEVICE_ATTR(end_lba
);
1307 static struct attribute
*blk_trace_attrs
[] = {
1308 &dev_attr_enable
.attr
,
1309 &dev_attr_act_mask
.attr
,
1311 &dev_attr_start_lba
.attr
,
1312 &dev_attr_end_lba
.attr
,
1316 struct attribute_group blk_trace_attr_group
= {
1318 .attrs
= blk_trace_attrs
,
1321 static const struct {
1325 { BLK_TC_READ
, "read" },
1326 { BLK_TC_WRITE
, "write" },
1327 { BLK_TC_BARRIER
, "barrier" },
1328 { BLK_TC_SYNC
, "sync" },
1329 { BLK_TC_QUEUE
, "queue" },
1330 { BLK_TC_REQUEUE
, "requeue" },
1331 { BLK_TC_ISSUE
, "issue" },
1332 { BLK_TC_COMPLETE
, "complete" },
1333 { BLK_TC_FS
, "fs" },
1334 { BLK_TC_PC
, "pc" },
1335 { BLK_TC_AHEAD
, "ahead" },
1336 { BLK_TC_META
, "meta" },
1337 { BLK_TC_DISCARD
, "discard" },
1338 { BLK_TC_DRV_DATA
, "drv_data" },
1341 static int blk_trace_str2mask(const char *str
)
1347 s
= kstrdup(str
, GFP_KERNEL
);
1353 token
= strsep(&s
, ",");
1360 for (i
= 0; i
< ARRAY_SIZE(mask_maps
); i
++) {
1361 if (strcasecmp(token
, mask_maps
[i
].str
) == 0) {
1362 mask
|= mask_maps
[i
].mask
;
1366 if (i
== ARRAY_SIZE(mask_maps
)) {
1376 static ssize_t
blk_trace_mask2str(char *buf
, int mask
)
1381 for (i
= 0; i
< ARRAY_SIZE(mask_maps
); i
++) {
1382 if (mask
& mask_maps
[i
].mask
) {
1383 p
+= sprintf(p
, "%s%s",
1384 (p
== buf
) ? "" : ",", mask_maps
[i
].str
);
1392 static struct request_queue
*blk_trace_get_queue(struct block_device
*bdev
)
1394 if (bdev
->bd_disk
== NULL
)
1397 return bdev_get_queue(bdev
);
1400 static ssize_t
sysfs_blk_trace_attr_show(struct device
*dev
,
1401 struct device_attribute
*attr
,
1404 struct hd_struct
*p
= dev_to_part(dev
);
1405 struct request_queue
*q
;
1406 struct block_device
*bdev
;
1407 ssize_t ret
= -ENXIO
;
1410 bdev
= bdget(part_devt(p
));
1412 goto out_unlock_kernel
;
1414 q
= blk_trace_get_queue(bdev
);
1418 mutex_lock(&bdev
->bd_mutex
);
1420 if (attr
== &dev_attr_enable
) {
1421 ret
= sprintf(buf
, "%u\n", !!q
->blk_trace
);
1422 goto out_unlock_bdev
;
1425 if (q
->blk_trace
== NULL
)
1426 ret
= sprintf(buf
, "disabled\n");
1427 else if (attr
== &dev_attr_act_mask
)
1428 ret
= blk_trace_mask2str(buf
, q
->blk_trace
->act_mask
);
1429 else if (attr
== &dev_attr_pid
)
1430 ret
= sprintf(buf
, "%u\n", q
->blk_trace
->pid
);
1431 else if (attr
== &dev_attr_start_lba
)
1432 ret
= sprintf(buf
, "%llu\n", q
->blk_trace
->start_lba
);
1433 else if (attr
== &dev_attr_end_lba
)
1434 ret
= sprintf(buf
, "%llu\n", q
->blk_trace
->end_lba
);
1437 mutex_unlock(&bdev
->bd_mutex
);
1445 static ssize_t
sysfs_blk_trace_attr_store(struct device
*dev
,
1446 struct device_attribute
*attr
,
1447 const char *buf
, size_t count
)
1449 struct block_device
*bdev
;
1450 struct request_queue
*q
;
1451 struct hd_struct
*p
;
1453 ssize_t ret
= -EINVAL
;
1458 if (attr
== &dev_attr_act_mask
) {
1459 if (sscanf(buf
, "%llx", &value
) != 1) {
1460 /* Assume it is a list of trace category names */
1461 ret
= blk_trace_str2mask(buf
);
1466 } else if (sscanf(buf
, "%llu", &value
) != 1)
1472 p
= dev_to_part(dev
);
1473 bdev
= bdget(part_devt(p
));
1475 goto out_unlock_kernel
;
1477 q
= blk_trace_get_queue(bdev
);
1481 mutex_lock(&bdev
->bd_mutex
);
1483 if (attr
== &dev_attr_enable
) {
1485 ret
= blk_trace_setup_queue(q
, bdev
->bd_dev
);
1487 ret
= blk_trace_remove_queue(q
);
1488 goto out_unlock_bdev
;
1492 if (q
->blk_trace
== NULL
)
1493 ret
= blk_trace_setup_queue(q
, bdev
->bd_dev
);
1496 if (attr
== &dev_attr_act_mask
)
1497 q
->blk_trace
->act_mask
= value
;
1498 else if (attr
== &dev_attr_pid
)
1499 q
->blk_trace
->pid
= value
;
1500 else if (attr
== &dev_attr_start_lba
)
1501 q
->blk_trace
->start_lba
= value
;
1502 else if (attr
== &dev_attr_end_lba
)
1503 q
->blk_trace
->end_lba
= value
;
1507 mutex_unlock(&bdev
->bd_mutex
);
1513 return ret
? ret
: count
;