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blktrace.c
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blktrace.c
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/*
* Copyright (C) 2006 Jens Axboe <[email protected]>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
*/
#include <linux/kernel.h>
#include <linux/blkdev.h>
#include <linux/blktrace_api.h>
#include <linux/percpu.h>
#include <linux/init.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/debugfs.h>
#include <linux/export.h>
#include <linux/time.h>
#include <linux/uaccess.h>
#include <linux/list.h>
#include <trace/events/block.h>
#include "trace_output.h"
#ifdef CONFIG_BLK_DEV_IO_TRACE
static unsigned int blktrace_seq __read_mostly = 1;
static struct trace_array *blk_tr;
static bool blk_tracer_enabled __read_mostly;
static LIST_HEAD(running_trace_list);
static __cacheline_aligned_in_smp DEFINE_SPINLOCK(running_trace_lock);
/* Select an alternative, minimalistic output than the original one */
#define TRACE_BLK_OPT_CLASSIC 0x1
static struct tracer_opt blk_tracer_opts[] = {
/* Default disable the minimalistic output */
{ TRACER_OPT(blk_classic, TRACE_BLK_OPT_CLASSIC) },
{ }
};
static struct tracer_flags blk_tracer_flags = {
.val = 0,
.opts = blk_tracer_opts,
};
/* Global reference count of probes */
static atomic_t blk_probes_ref = ATOMIC_INIT(0);
static void blk_register_tracepoints(void);
static void blk_unregister_tracepoints(void);
/*
* Send out a notify message.
*/
static void trace_note(struct blk_trace *bt, pid_t pid, int action,
const void *data, size_t len)
{
struct blk_io_trace *t;
struct ring_buffer_event *event = NULL;
struct ring_buffer *buffer = NULL;
int pc = 0;
int cpu = smp_processor_id();
bool blk_tracer = blk_tracer_enabled;
if (blk_tracer) {
buffer = blk_tr->trace_buffer.buffer;
pc = preempt_count();
event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
sizeof(*t) + len,
0, pc);
if (!event)
return;
t = ring_buffer_event_data(event);
goto record_it;
}
if (!bt->rchan)
return;
t = relay_reserve(bt->rchan, sizeof(*t) + len);
if (t) {
t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
t->time = ktime_to_ns(ktime_get());
record_it:
t->device = bt->dev;
t->action = action;
t->pid = pid;
t->cpu = cpu;
t->pdu_len = len;
memcpy((void *) t + sizeof(*t), data, len);
if (blk_tracer)
trace_buffer_unlock_commit(blk_tr, buffer, event, 0, pc);
}
}
/*
* Send out a notify for this process, if we haven't done so since a trace
* started
*/
static void trace_note_tsk(struct task_struct *tsk)
{
unsigned long flags;
struct blk_trace *bt;
tsk->btrace_seq = blktrace_seq;
spin_lock_irqsave(&running_trace_lock, flags);
list_for_each_entry(bt, &running_trace_list, running_list) {
trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm,
sizeof(tsk->comm));
}
spin_unlock_irqrestore(&running_trace_lock, flags);
}
static void trace_note_time(struct blk_trace *bt)
{
struct timespec now;
unsigned long flags;
u32 words[2];
getnstimeofday(&now);
words[0] = now.tv_sec;
words[1] = now.tv_nsec;
local_irq_save(flags);
trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words));
local_irq_restore(flags);
}
void __trace_note_message(struct blk_trace *bt, const char *fmt, ...)
{
int n;
va_list args;
unsigned long flags;
char *buf;
if (unlikely(bt->trace_state != Blktrace_running &&
!blk_tracer_enabled))
return;
/*
* If the BLK_TC_NOTIFY action mask isn't set, don't send any note
* message to the trace.
*/
if (!(bt->act_mask & BLK_TC_NOTIFY))
return;
local_irq_save(flags);
buf = this_cpu_ptr(bt->msg_data);
va_start(args, fmt);
n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args);
va_end(args);
trace_note(bt, 0, BLK_TN_MESSAGE, buf, n);
local_irq_restore(flags);
}
EXPORT_SYMBOL_GPL(__trace_note_message);
static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
pid_t pid)
{
if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0)
return 1;
if (sector && (sector < bt->start_lba || sector > bt->end_lba))
return 1;
if (bt->pid && pid != bt->pid)
return 1;
return 0;
}
/*
* Data direction bit lookup
*/
static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ),
BLK_TC_ACT(BLK_TC_WRITE) };
#define BLK_TC_RAHEAD BLK_TC_AHEAD
/* The ilog2() calls fall out because they're constant */
#define MASK_TC_BIT(rw, __name) ((rw & REQ_ ## __name) << \
(ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - __REQ_ ## __name))
/*
* The worker for the various blk_add_trace*() types. Fills out a
* blk_io_trace structure and places it in a per-cpu subbuffer.
*/
static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
int rw, u32 what, int error, int pdu_len, void *pdu_data)
{
struct task_struct *tsk = current;
struct ring_buffer_event *event = NULL;
struct ring_buffer *buffer = NULL;
struct blk_io_trace *t;
unsigned long flags = 0;
unsigned long *sequence;
pid_t pid;
int cpu, pc = 0;
bool blk_tracer = blk_tracer_enabled;
if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer))
return;
what |= ddir_act[rw & WRITE];
what |= MASK_TC_BIT(rw, SYNC);
what |= MASK_TC_BIT(rw, RAHEAD);
what |= MASK_TC_BIT(rw, META);
what |= MASK_TC_BIT(rw, DISCARD);
what |= MASK_TC_BIT(rw, FLUSH);
what |= MASK_TC_BIT(rw, FUA);
pid = tsk->pid;
if (act_log_check(bt, what, sector, pid))
return;
cpu = raw_smp_processor_id();
if (blk_tracer) {
tracing_record_cmdline(current);
buffer = blk_tr->trace_buffer.buffer;
pc = preempt_count();
event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
sizeof(*t) + pdu_len,
0, pc);
if (!event)
return;
t = ring_buffer_event_data(event);
goto record_it;
}
if (unlikely(tsk->btrace_seq != blktrace_seq))
trace_note_tsk(tsk);
/*
* A word about the locking here - we disable interrupts to reserve
* some space in the relay per-cpu buffer, to prevent an irq
* from coming in and stepping on our toes.
*/
local_irq_save(flags);
t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len);
if (t) {
sequence = per_cpu_ptr(bt->sequence, cpu);
t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
t->sequence = ++(*sequence);
t->time = ktime_to_ns(ktime_get());
record_it:
/*
* These two are not needed in ftrace as they are in the
* generic trace_entry, filled by tracing_generic_entry_update,
* but for the trace_event->bin() synthesizer benefit we do it
* here too.
*/
t->cpu = cpu;
t->pid = pid;
t->sector = sector;
t->bytes = bytes;
t->action = what;
t->device = bt->dev;
t->error = error;
t->pdu_len = pdu_len;
if (pdu_len)
memcpy((void *) t + sizeof(*t), pdu_data, pdu_len);
if (blk_tracer) {
trace_buffer_unlock_commit(blk_tr, buffer, event, 0, pc);
return;
}
}
local_irq_restore(flags);
}
static struct dentry *blk_tree_root;
static DEFINE_MUTEX(blk_tree_mutex);
static void blk_trace_free(struct blk_trace *bt)
{
debugfs_remove(bt->msg_file);
debugfs_remove(bt->dropped_file);
relay_close(bt->rchan);
debugfs_remove(bt->dir);
free_percpu(bt->sequence);
free_percpu(bt->msg_data);
kfree(bt);
}
static void blk_trace_cleanup(struct blk_trace *bt)
{
blk_trace_free(bt);
if (atomic_dec_and_test(&blk_probes_ref))
blk_unregister_tracepoints();
}
int blk_trace_remove(struct request_queue *q)
{
struct blk_trace *bt;
bt = xchg(&q->blk_trace, NULL);
if (!bt)
return -EINVAL;
if (bt->trace_state != Blktrace_running)
blk_trace_cleanup(bt);
return 0;
}
EXPORT_SYMBOL_GPL(blk_trace_remove);
static ssize_t blk_dropped_read(struct file *filp, char __user *buffer,
size_t count, loff_t *ppos)
{
struct blk_trace *bt = filp->private_data;
char buf[16];
snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped));
return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf));
}
static const struct file_operations blk_dropped_fops = {
.owner = THIS_MODULE,
.open = simple_open,
.read = blk_dropped_read,
.llseek = default_llseek,
};
static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
size_t count, loff_t *ppos)
{
char *msg;
struct blk_trace *bt;
if (count >= BLK_TN_MAX_MSG)
return -EINVAL;
msg = memdup_user_nul(buffer, count);
if (IS_ERR(msg))
return PTR_ERR(msg);
bt = filp->private_data;
__trace_note_message(bt, "%s", msg);
kfree(msg);
return count;
}
static const struct file_operations blk_msg_fops = {
.owner = THIS_MODULE,
.open = simple_open,
.write = blk_msg_write,
.llseek = noop_llseek,
};
/*
* Keep track of how many times we encountered a full subbuffer, to aid
* the user space app in telling how many lost events there were.
*/
static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
void *prev_subbuf, size_t prev_padding)
{
struct blk_trace *bt;
if (!relay_buf_full(buf))
return 1;
bt = buf->chan->private_data;
atomic_inc(&bt->dropped);
return 0;
}
static int blk_remove_buf_file_callback(struct dentry *dentry)
{
debugfs_remove(dentry);
return 0;
}
static struct dentry *blk_create_buf_file_callback(const char *filename,
struct dentry *parent,
umode_t mode,
struct rchan_buf *buf,
int *is_global)
{
return debugfs_create_file(filename, mode, parent, buf,
&relay_file_operations);
}
static struct rchan_callbacks blk_relay_callbacks = {
.subbuf_start = blk_subbuf_start_callback,
.create_buf_file = blk_create_buf_file_callback,
.remove_buf_file = blk_remove_buf_file_callback,
};
static void blk_trace_setup_lba(struct blk_trace *bt,
struct block_device *bdev)
{
struct hd_struct *part = NULL;
if (bdev)
part = bdev->bd_part;
if (part) {
bt->start_lba = part->start_sect;
bt->end_lba = part->start_sect + part->nr_sects;
} else {
bt->start_lba = 0;
bt->end_lba = -1ULL;
}
}
/*
* Setup everything required to start tracing
*/
int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
struct block_device *bdev,
struct blk_user_trace_setup *buts)
{
struct blk_trace *bt = NULL;
struct dentry *dir = NULL;
int ret;
if (!buts->buf_size || !buts->buf_nr)
return -EINVAL;
strncpy(buts->name, name, BLKTRACE_BDEV_SIZE);
buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0';
/*
* some device names have larger paths - convert the slashes
* to underscores for this to work as expected
*/
strreplace(buts->name, '/', '_');
bt = kzalloc(sizeof(*bt), GFP_KERNEL);
if (!bt)
return -ENOMEM;
ret = -ENOMEM;
bt->sequence = alloc_percpu(unsigned long);
if (!bt->sequence)
goto err;
bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
if (!bt->msg_data)
goto err;
ret = -ENOENT;
mutex_lock(&blk_tree_mutex);
if (!blk_tree_root) {
blk_tree_root = debugfs_create_dir("block", NULL);
if (!blk_tree_root) {
mutex_unlock(&blk_tree_mutex);
goto err;
}
}
mutex_unlock(&blk_tree_mutex);
dir = debugfs_create_dir(buts->name, blk_tree_root);
if (!dir)
goto err;
bt->dir = dir;
bt->dev = dev;
atomic_set(&bt->dropped, 0);
INIT_LIST_HEAD(&bt->running_list);
ret = -EIO;
bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt,
&blk_dropped_fops);
if (!bt->dropped_file)
goto err;
bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
if (!bt->msg_file)
goto err;
bt->rchan = relay_open("trace", dir, buts->buf_size,
buts->buf_nr, &blk_relay_callbacks, bt);
if (!bt->rchan)
goto err;
bt->act_mask = buts->act_mask;
if (!bt->act_mask)
bt->act_mask = (u16) -1;
blk_trace_setup_lba(bt, bdev);
/* overwrite with user settings */
if (buts->start_lba)
bt->start_lba = buts->start_lba;
if (buts->end_lba)
bt->end_lba = buts->end_lba;
bt->pid = buts->pid;
bt->trace_state = Blktrace_setup;
ret = -EBUSY;
if (cmpxchg(&q->blk_trace, NULL, bt))
goto err;
if (atomic_inc_return(&blk_probes_ref) == 1)
blk_register_tracepoints();
return 0;
err:
blk_trace_free(bt);
return ret;
}
int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
struct block_device *bdev,
char __user *arg)
{
struct blk_user_trace_setup buts;
int ret;
ret = copy_from_user(&buts, arg, sizeof(buts));
if (ret)
return -EFAULT;
ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
if (ret)
return ret;
if (copy_to_user(arg, &buts, sizeof(buts))) {
blk_trace_remove(q);
return -EFAULT;
}
return 0;
}
EXPORT_SYMBOL_GPL(blk_trace_setup);
#if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
static int compat_blk_trace_setup(struct request_queue *q, char *name,
dev_t dev, struct block_device *bdev,
char __user *arg)
{
struct blk_user_trace_setup buts;
struct compat_blk_user_trace_setup cbuts;
int ret;
if (copy_from_user(&cbuts, arg, sizeof(cbuts)))
return -EFAULT;
buts = (struct blk_user_trace_setup) {
.act_mask = cbuts.act_mask,
.buf_size = cbuts.buf_size,
.buf_nr = cbuts.buf_nr,
.start_lba = cbuts.start_lba,
.end_lba = cbuts.end_lba,
.pid = cbuts.pid,
};
ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
if (ret)
return ret;
if (copy_to_user(arg, &buts.name, ARRAY_SIZE(buts.name))) {
blk_trace_remove(q);
return -EFAULT;
}
return 0;
}
#endif
int blk_trace_startstop(struct request_queue *q, int start)
{
int ret;
struct blk_trace *bt = q->blk_trace;
if (bt == NULL)
return -EINVAL;
/*
* For starting a trace, we can transition from a setup or stopped
* trace. For stopping a trace, the state must be running
*/
ret = -EINVAL;
if (start) {
if (bt->trace_state == Blktrace_setup ||
bt->trace_state == Blktrace_stopped) {
blktrace_seq++;
smp_mb();
bt->trace_state = Blktrace_running;
spin_lock_irq(&running_trace_lock);
list_add(&bt->running_list, &running_trace_list);
spin_unlock_irq(&running_trace_lock);
trace_note_time(bt);
ret = 0;
}
} else {
if (bt->trace_state == Blktrace_running) {
bt->trace_state = Blktrace_stopped;
spin_lock_irq(&running_trace_lock);
list_del_init(&bt->running_list);
spin_unlock_irq(&running_trace_lock);
relay_flush(bt->rchan);
ret = 0;
}
}
return ret;
}
EXPORT_SYMBOL_GPL(blk_trace_startstop);
/**
* blk_trace_ioctl: - handle the ioctls associated with tracing
* @bdev: the block device
* @cmd: the ioctl cmd
* @arg: the argument data, if any
*
**/
int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
{
struct request_queue *q;
int ret, start = 0;
char b[BDEVNAME_SIZE];
q = bdev_get_queue(bdev);
if (!q)
return -ENXIO;
mutex_lock(&bdev->bd_mutex);
switch (cmd) {
case BLKTRACESETUP:
bdevname(bdev, b);
ret = blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
break;
#if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
case BLKTRACESETUP32:
bdevname(bdev, b);
ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
break;
#endif
case BLKTRACESTART:
start = 1;
case BLKTRACESTOP:
ret = blk_trace_startstop(q, start);
break;
case BLKTRACETEARDOWN:
ret = blk_trace_remove(q);
break;
default:
ret = -ENOTTY;
break;
}
mutex_unlock(&bdev->bd_mutex);
return ret;
}
/**
* blk_trace_shutdown: - stop and cleanup trace structures
* @q: the request queue associated with the device
*
**/
void blk_trace_shutdown(struct request_queue *q)
{
if (q->blk_trace) {
blk_trace_startstop(q, 0);
blk_trace_remove(q);
}
}
/*
* blktrace probes
*/
/**
* blk_add_trace_rq - Add a trace for a request oriented action
* @q: queue the io is for
* @rq: the source request
* @nr_bytes: number of completed bytes
* @what: the action
*
* Description:
* Records an action against a request. Will log the bio offset + size.
*
**/
static void blk_add_trace_rq(struct request_queue *q, struct request *rq,
unsigned int nr_bytes, u32 what)
{
struct blk_trace *bt = q->blk_trace;
if (likely(!bt))
return;
if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
what |= BLK_TC_ACT(BLK_TC_PC);
__blk_add_trace(bt, 0, nr_bytes, rq->cmd_flags,
what, rq->errors, rq->cmd_len, rq->cmd);
} else {
what |= BLK_TC_ACT(BLK_TC_FS);
__blk_add_trace(bt, blk_rq_pos(rq), nr_bytes,
rq->cmd_flags, what, rq->errors, 0, NULL);
}
}
static void blk_add_trace_rq_abort(void *ignore,
struct request_queue *q, struct request *rq)
{
blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_ABORT);
}
static void blk_add_trace_rq_insert(void *ignore,
struct request_queue *q, struct request *rq)
{
blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_INSERT);
}
static void blk_add_trace_rq_issue(void *ignore,
struct request_queue *q, struct request *rq)
{
blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_ISSUE);
}
static void blk_add_trace_rq_requeue(void *ignore,
struct request_queue *q,
struct request *rq)
{
blk_add_trace_rq(q, rq, blk_rq_bytes(rq), BLK_TA_REQUEUE);
}
static void blk_add_trace_rq_complete(void *ignore,
struct request_queue *q,
struct request *rq,
unsigned int nr_bytes)
{
blk_add_trace_rq(q, rq, nr_bytes, BLK_TA_COMPLETE);
}
/**
* blk_add_trace_bio - Add a trace for a bio oriented action
* @q: queue the io is for
* @bio: the source bio
* @what: the action
* @error: error, if any
*
* Description:
* Records an action against a bio. Will log the bio offset + size.
*
**/
static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
u32 what, int error)
{
struct blk_trace *bt = q->blk_trace;
if (likely(!bt))
return;
__blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
bio->bi_rw, what, error, 0, NULL);
}
static void blk_add_trace_bio_bounce(void *ignore,
struct request_queue *q, struct bio *bio)
{
blk_add_trace_bio(q, bio, BLK_TA_BOUNCE, 0);
}
static void blk_add_trace_bio_complete(void *ignore,
struct request_queue *q, struct bio *bio,
int error)
{
blk_add_trace_bio(q, bio, BLK_TA_COMPLETE, error);
}
static void blk_add_trace_bio_backmerge(void *ignore,
struct request_queue *q,
struct request *rq,
struct bio *bio)
{
blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE, 0);
}
static void blk_add_trace_bio_frontmerge(void *ignore,
struct request_queue *q,
struct request *rq,
struct bio *bio)
{
blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE, 0);
}
static void blk_add_trace_bio_queue(void *ignore,
struct request_queue *q, struct bio *bio)
{
blk_add_trace_bio(q, bio, BLK_TA_QUEUE, 0);
}
static void blk_add_trace_getrq(void *ignore,
struct request_queue *q,
struct bio *bio, int rw)
{
if (bio)
blk_add_trace_bio(q, bio, BLK_TA_GETRQ, 0);
else {
struct blk_trace *bt = q->blk_trace;
if (bt)
__blk_add_trace(bt, 0, 0, rw, BLK_TA_GETRQ, 0, 0, NULL);
}
}
static void blk_add_trace_sleeprq(void *ignore,
struct request_queue *q,
struct bio *bio, int rw)
{
if (bio)
blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ, 0);
else {
struct blk_trace *bt = q->blk_trace;
if (bt)
__blk_add_trace(bt, 0, 0, rw, BLK_TA_SLEEPRQ,
0, 0, NULL);
}
}
static void blk_add_trace_plug(void *ignore, struct request_queue *q)
{
struct blk_trace *bt = q->blk_trace;
if (bt)
__blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL);
}
static void blk_add_trace_unplug(void *ignore, struct request_queue *q,
unsigned int depth, bool explicit)
{
struct blk_trace *bt = q->blk_trace;
if (bt) {
__be64 rpdu = cpu_to_be64(depth);
u32 what;
if (explicit)
what = BLK_TA_UNPLUG_IO;
else
what = BLK_TA_UNPLUG_TIMER;
__blk_add_trace(bt, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu);
}
}
static void blk_add_trace_split(void *ignore,
struct request_queue *q, struct bio *bio,
unsigned int pdu)
{
struct blk_trace *bt = q->blk_trace;
if (bt) {
__be64 rpdu = cpu_to_be64(pdu);
__blk_add_trace(bt, bio->bi_iter.bi_sector,
bio->bi_iter.bi_size, bio->bi_rw, BLK_TA_SPLIT,
bio->bi_error, sizeof(rpdu), &rpdu);
}
}
/**
* blk_add_trace_bio_remap - Add a trace for a bio-remap operation
* @ignore: trace callback data parameter (not used)
* @q: queue the io is for
* @bio: the source bio
* @dev: target device
* @from: source sector
*
* Description:
* Device mapper or raid target sometimes need to split a bio because
* it spans a stripe (or similar). Add a trace for that action.
*
**/
static void blk_add_trace_bio_remap(void *ignore,
struct request_queue *q, struct bio *bio,
dev_t dev, sector_t from)
{
struct blk_trace *bt = q->blk_trace;
struct blk_io_trace_remap r;
if (likely(!bt))
return;
r.device_from = cpu_to_be32(dev);
r.device_to = cpu_to_be32(bio->bi_bdev->bd_dev);
r.sector_from = cpu_to_be64(from);
__blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
bio->bi_rw, BLK_TA_REMAP, bio->bi_error,
sizeof(r), &r);
}
/**
* blk_add_trace_rq_remap - Add a trace for a request-remap operation
* @ignore: trace callback data parameter (not used)
* @q: queue the io is for
* @rq: the source request
* @dev: target device
* @from: source sector
*
* Description:
* Device mapper remaps request to other devices.
* Add a trace for that action.
*
**/
static void blk_add_trace_rq_remap(void *ignore,
struct request_queue *q,
struct request *rq, dev_t dev,
sector_t from)
{
struct blk_trace *bt = q->blk_trace;
struct blk_io_trace_remap r;
if (likely(!bt))
return;
r.device_from = cpu_to_be32(dev);
r.device_to = cpu_to_be32(disk_devt(rq->rq_disk));
r.sector_from = cpu_to_be64(from);
__blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
rq_data_dir(rq), BLK_TA_REMAP, !!rq->errors,
sizeof(r), &r);
}
/**
* blk_add_driver_data - Add binary message with driver-specific data
* @q: queue the io is for
* @rq: io request
* @data: driver-specific data
* @len: length of driver-specific data
*
* Description:
* Some drivers might want to write driver-specific data per request.
*
**/
void blk_add_driver_data(struct request_queue *q,
struct request *rq,
void *data, size_t len)
{
struct blk_trace *bt = q->blk_trace;
if (likely(!bt))
return;
if (rq->cmd_type == REQ_TYPE_BLOCK_PC)
__blk_add_trace(bt, 0, blk_rq_bytes(rq), 0,
BLK_TA_DRV_DATA, rq->errors, len, data);
else
__blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 0,
BLK_TA_DRV_DATA, rq->errors, len, data);
}
EXPORT_SYMBOL_GPL(blk_add_driver_data);
static void blk_register_tracepoints(void)
{
int ret;
ret = register_trace_block_rq_abort(blk_add_trace_rq_abort, NULL);
WARN_ON(ret);
ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
WARN_ON(ret);
ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
WARN_ON(ret);
ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
WARN_ON(ret);
ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
WARN_ON(ret);
ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
WARN_ON(ret);
ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
WARN_ON(ret);
ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
WARN_ON(ret);
ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
WARN_ON(ret);
ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
WARN_ON(ret);
ret = register_trace_block_getrq(blk_add_trace_getrq, NULL);