If unsure, say N.
-config BLK_DEV_IO_TRACE
- bool "Support for tracing block io actions"
- depends on SYSFS
- select RELAY
- select DEBUG_FS
- select TRACEPOINTS
- select TRACING
- select STACKTRACE
- help
- Say Y here if you want to be able to trace the block layer actions
- on a given queue. Tracing allows you to see any traffic happening
- on a block device queue. For more information (and the userspace
- support tools needed), fetch the blktrace tools from:
-
- git://git.kernel.dk/blktrace.git
-
- Tracing also is possible using the ftrace interface, e.g.:
-
- echo 1 > /sys/block/sda/sda1/trace/enable
- echo blk > /sys/kernel/debug/tracing/current_tracer
- cat /sys/kernel/debug/tracing/trace_pipe
-
- If unsure, say N.
-
config BLK_DEV_BSG
bool "Block layer SG support v4 (EXPERIMENTAL)"
depends on EXPERIMENTAL
obj-$(CONFIG_IOSCHED_DEADLINE) += deadline-iosched.o
obj-$(CONFIG_IOSCHED_CFQ) += cfq-iosched.o
-obj-$(CONFIG_BLK_DEV_IO_TRACE) += blktrace.o
obj-$(CONFIG_BLOCK_COMPAT) += compat_ioctl.o
obj-$(CONFIG_BLK_DEV_INTEGRITY) += blk-integrity.o
+++ /dev/null
-/*
- * Copyright (C) 2006 Jens Axboe <axboe@kernel.dk>
- *
- * 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/debugfs.h>
-#include <linux/time.h>
-#include <trace/block.h>
-#include <linux/uaccess.h>
-#include <../kernel/trace/trace_output.h>
-
-static unsigned int blktrace_seq __read_mostly = 1;
-
-static struct trace_array *blk_tr;
-static int __read_mostly blk_tracer_enabled;
-
-/* 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 DEFINE_MUTEX(blk_probe_mutex);
-static atomic_t blk_probes_ref = ATOMIC_INIT(0);
-
-static int 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;
-
- if (!bt->rchan)
- return;
-
- t = relay_reserve(bt->rchan, sizeof(*t) + len);
- if (t) {
- const int cpu = smp_processor_id();
-
- t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
- t->time = ktime_to_ns(ktime_get());
- t->device = bt->dev;
- t->action = action;
- t->pid = pid;
- t->cpu = cpu;
- t->pdu_len = len;
- memcpy((void *) t + sizeof(*t), data, len);
- }
-}
-
-/*
- * Send out a notify for this process, if we haven't done so since a trace
- * started
- */
-static void trace_note_tsk(struct blk_trace *bt, struct task_struct *tsk)
-{
- tsk->btrace_seq = blktrace_seq;
- trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm, sizeof(tsk->comm));
-}
-
-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 (blk_tr) {
- va_start(args, fmt);
- ftrace_vprintk(fmt, args);
- va_end(args);
- return;
- }
-
- if (!bt->msg_data)
- return;
-
- local_irq_save(flags);
- buf = per_cpu_ptr(bt->msg_data, smp_processor_id());
- 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 < bt->start_lba || sector > bt->end_lba)
- return 1;
- if (bt->pid && pid != bt->pid)
- return 1;
-
- return 0;
-}
-
-/*
- * Data direction bit lookup
- */
-static u32 ddir_act[2] __read_mostly = { BLK_TC_ACT(BLK_TC_READ),
- BLK_TC_ACT(BLK_TC_WRITE) };
-
-/* The ilog2() calls fall out because they're constant */
-#define MASK_TC_BIT(rw, __name) ((rw & (1 << BIO_RW_ ## __name)) << \
- (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - BIO_RW_ ## __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 blk_io_trace *t;
- unsigned long flags = 0;
- unsigned long *sequence;
- pid_t pid;
- int cpu, pc = 0;
-
- if (unlikely(bt->trace_state != Blktrace_running ||
- !blk_tracer_enabled))
- return;
-
- what |= ddir_act[rw & WRITE];
- what |= MASK_TC_BIT(rw, BARRIER);
- what |= MASK_TC_BIT(rw, SYNC);
- what |= MASK_TC_BIT(rw, AHEAD);
- what |= MASK_TC_BIT(rw, META);
- what |= MASK_TC_BIT(rw, DISCARD);
-
- pid = tsk->pid;
- if (unlikely(act_log_check(bt, what, sector, pid)))
- return;
- cpu = raw_smp_processor_id();
-
- if (blk_tr) {
- tracing_record_cmdline(current);
-
- pc = preempt_count();
- event = trace_buffer_lock_reserve(blk_tr, TRACE_BLK,
- sizeof(*t) + pdu_len,
- 0, pc);
- if (!event)
- return;
- t = ring_buffer_event_data(event);
- goto record_it;
- }
-
- /*
- * 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);
-
- if (unlikely(tsk->btrace_seq != blktrace_seq))
- trace_note_tsk(bt, tsk);
-
- 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_tr) {
- trace_buffer_unlock_commit(blk_tr, event, 0, pc);
- return;
- }
- }
-
- local_irq_restore(flags);
-}
-
-static struct dentry *blk_tree_root;
-static DEFINE_MUTEX(blk_tree_mutex);
-
-static void blk_trace_cleanup(struct blk_trace *bt)
-{
- debugfs_remove(bt->msg_file);
- debugfs_remove(bt->dropped_file);
- relay_close(bt->rchan);
- free_percpu(bt->sequence);
- free_percpu(bt->msg_data);
- kfree(bt);
- mutex_lock(&blk_probe_mutex);
- if (atomic_dec_and_test(&blk_probes_ref))
- blk_unregister_tracepoints();
- mutex_unlock(&blk_probe_mutex);
-}
-
-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_setup ||
- bt->trace_state == Blktrace_stopped)
- blk_trace_cleanup(bt);
-
- return 0;
-}
-EXPORT_SYMBOL_GPL(blk_trace_remove);
-
-static int blk_dropped_open(struct inode *inode, struct file *filp)
-{
- filp->private_data = inode->i_private;
-
- return 0;
-}
-
-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 = blk_dropped_open,
- .read = blk_dropped_read,
-};
-
-static int blk_msg_open(struct inode *inode, struct file *filp)
-{
- filp->private_data = inode->i_private;
-
- return 0;
-}
-
-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 = kmalloc(count, GFP_KERNEL);
- if (msg == NULL)
- return -ENOMEM;
-
- if (copy_from_user(msg, buffer, count)) {
- kfree(msg);
- return -EFAULT;
- }
-
- 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 = blk_msg_open,
- .write = blk_msg_write,
-};
-
-/*
- * 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)
-{
- struct dentry *parent = dentry->d_parent;
- debugfs_remove(dentry);
-
- /*
- * this will fail for all but the last file, but that is ok. what we
- * care about is the top level buts->name directory going away, when
- * the last trace file is gone. Then we don't have to rmdir() that
- * manually on trace stop, so it nicely solves the issue with
- * force killing of running traces.
- */
-
- debugfs_remove(parent);
- return 0;
-}
-
-static struct dentry *blk_create_buf_file_callback(const char *filename,
- struct dentry *parent,
- int 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,
-};
-
-/*
- * Setup everything required to start tracing
- */
-int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
- struct blk_user_trace_setup *buts)
-{
- struct blk_trace *old_bt, *bt = NULL;
- struct dentry *dir = NULL;
- int ret, i;
-
- 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
- */
- for (i = 0; i < strlen(buts->name); i++)
- if (buts->name[i] == '/')
- buts->name[i] = '_';
-
- ret = -ENOMEM;
- bt = kzalloc(sizeof(*bt), GFP_KERNEL);
- if (!bt)
- goto err;
-
- bt->sequence = alloc_percpu(unsigned long);
- if (!bt->sequence)
- goto err;
-
- bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG);
- if (!bt->msg_data)
- goto err;
-
- ret = -ENOENT;
-
- if (!blk_tree_root) {
- blk_tree_root = debugfs_create_dir("block", NULL);
- if (!blk_tree_root)
- return -ENOMEM;
- }
-
- dir = debugfs_create_dir(buts->name, blk_tree_root);
-
- if (!dir)
- goto err;
-
- bt->dir = dir;
- bt->dev = dev;
- atomic_set(&bt->dropped, 0);
-
- 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;
-
- bt->start_lba = buts->start_lba;
- bt->end_lba = buts->end_lba;
- if (!bt->end_lba)
- bt->end_lba = -1ULL;
-
- bt->pid = buts->pid;
- bt->trace_state = Blktrace_setup;
-
- mutex_lock(&blk_probe_mutex);
- if (atomic_add_return(1, &blk_probes_ref) == 1) {
- ret = blk_register_tracepoints();
- if (ret)
- goto probe_err;
- }
- mutex_unlock(&blk_probe_mutex);
-
- ret = -EBUSY;
- old_bt = xchg(&q->blk_trace, bt);
- if (old_bt) {
- (void) xchg(&q->blk_trace, old_bt);
- goto err;
- }
-
- return 0;
-probe_err:
- atomic_dec(&blk_probes_ref);
- mutex_unlock(&blk_probe_mutex);
-err:
- if (bt) {
- if (bt->msg_file)
- debugfs_remove(bt->msg_file);
- if (bt->dropped_file)
- debugfs_remove(bt->dropped_file);
- free_percpu(bt->sequence);
- free_percpu(bt->msg_data);
- if (bt->rchan)
- relay_close(bt->rchan);
- kfree(bt);
- }
- return ret;
-}
-
-int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
- 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, &buts);
- if (ret)
- return ret;
-
- if (copy_to_user(arg, &buts, sizeof(buts)))
- return -EFAULT;
-
- return 0;
-}
-EXPORT_SYMBOL_GPL(blk_trace_setup);
-
-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;
-
- trace_note_time(bt);
- ret = 0;
- }
- } else {
- if (bt->trace_state == Blktrace_running) {
- bt->trace_state = Blktrace_stopped;
- 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, arg);
- break;
- 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
- * @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,
- u32 what)
-{
- struct blk_trace *bt = q->blk_trace;
- int rw = rq->cmd_flags & 0x03;
-
- if (likely(!bt))
- return;
-
- if (blk_discard_rq(rq))
- rw |= (1 << BIO_RW_DISCARD);
-
- if (blk_pc_request(rq)) {
- what |= BLK_TC_ACT(BLK_TC_PC);
- __blk_add_trace(bt, 0, rq->data_len, rw, what, rq->errors,
- sizeof(rq->cmd), rq->cmd);
- } else {
- what |= BLK_TC_ACT(BLK_TC_FS);
- __blk_add_trace(bt, rq->hard_sector, rq->hard_nr_sectors << 9,
- rw, what, rq->errors, 0, NULL);
- }
-}
-
-static void blk_add_trace_rq_abort(struct request_queue *q, struct request *rq)
-{
- blk_add_trace_rq(q, rq, BLK_TA_ABORT);
-}
-
-static void blk_add_trace_rq_insert(struct request_queue *q, struct request *rq)
-{
- blk_add_trace_rq(q, rq, BLK_TA_INSERT);
-}
-
-static void blk_add_trace_rq_issue(struct request_queue *q, struct request *rq)
-{
- blk_add_trace_rq(q, rq, BLK_TA_ISSUE);
-}
-
-static void blk_add_trace_rq_requeue(struct request_queue *q,
- struct request *rq)
-{
- blk_add_trace_rq(q, rq, BLK_TA_REQUEUE);
-}
-
-static void blk_add_trace_rq_complete(struct request_queue *q,
- struct request *rq)
-{
- blk_add_trace_rq(q, rq, 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
- *
- * 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)
-{
- struct blk_trace *bt = q->blk_trace;
-
- if (likely(!bt))
- return;
-
- __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, what,
- !bio_flagged(bio, BIO_UPTODATE), 0, NULL);
-}
-
-static void blk_add_trace_bio_bounce(struct request_queue *q, struct bio *bio)
-{
- blk_add_trace_bio(q, bio, BLK_TA_BOUNCE);
-}
-
-static void blk_add_trace_bio_complete(struct request_queue *q, struct bio *bio)
-{
- blk_add_trace_bio(q, bio, BLK_TA_COMPLETE);
-}
-
-static void blk_add_trace_bio_backmerge(struct request_queue *q,
- struct bio *bio)
-{
- blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE);
-}
-
-static void blk_add_trace_bio_frontmerge(struct request_queue *q,
- struct bio *bio)
-{
- blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE);
-}
-
-static void blk_add_trace_bio_queue(struct request_queue *q, struct bio *bio)
-{
- blk_add_trace_bio(q, bio, BLK_TA_QUEUE);
-}
-
-static void blk_add_trace_getrq(struct request_queue *q,
- struct bio *bio, int rw)
-{
- if (bio)
- blk_add_trace_bio(q, bio, BLK_TA_GETRQ);
- 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(struct request_queue *q,
- struct bio *bio, int rw)
-{
- if (bio)
- blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ);
- 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(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_io(struct request_queue *q)
-{
- struct blk_trace *bt = q->blk_trace;
-
- if (bt) {
- unsigned int pdu = q->rq.count[READ] + q->rq.count[WRITE];
- __be64 rpdu = cpu_to_be64(pdu);
-
- __blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_IO, 0,
- sizeof(rpdu), &rpdu);
- }
-}
-
-static void blk_add_trace_unplug_timer(struct request_queue *q)
-{
- struct blk_trace *bt = q->blk_trace;
-
- if (bt) {
- unsigned int pdu = q->rq.count[READ] + q->rq.count[WRITE];
- __be64 rpdu = cpu_to_be64(pdu);
-
- __blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_TIMER, 0,
- sizeof(rpdu), &rpdu);
- }
-}
-
-static void blk_add_trace_split(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_sector, bio->bi_size, bio->bi_rw,
- BLK_TA_SPLIT, !bio_flagged(bio, BIO_UPTODATE),
- sizeof(rpdu), &rpdu);
- }
-}
-
-/**
- * blk_add_trace_remap - Add a trace for a remap operation
- * @q: queue the io is for
- * @bio: the source bio
- * @dev: target device
- * @from: source sector
- * @to: target 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_remap(struct request_queue *q, struct bio *bio,
- dev_t dev, sector_t from, sector_t to)
-{
- struct blk_trace *bt = q->blk_trace;
- struct blk_io_trace_remap r;
-
- if (likely(!bt))
- return;
-
- r.device = cpu_to_be32(dev);
- r.device_from = cpu_to_be32(bio->bi_bdev->bd_dev);
- r.sector = cpu_to_be64(to);
-
- __blk_add_trace(bt, from, bio->bi_size, bio->bi_rw, BLK_TA_REMAP,
- !bio_flagged(bio, BIO_UPTODATE), 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 (blk_pc_request(rq))
- __blk_add_trace(bt, 0, rq->data_len, 0, BLK_TA_DRV_DATA,
- rq->errors, len, data);
- else
- __blk_add_trace(bt, rq->hard_sector, rq->hard_nr_sectors << 9,
- 0, BLK_TA_DRV_DATA, rq->errors, len, data);
-}
-EXPORT_SYMBOL_GPL(blk_add_driver_data);
-
-static int blk_register_tracepoints(void)
-{
- int ret;
-
- ret = register_trace_block_rq_abort(blk_add_trace_rq_abort);
- WARN_ON(ret);
- ret = register_trace_block_rq_insert(blk_add_trace_rq_insert);
- WARN_ON(ret);
- ret = register_trace_block_rq_issue(blk_add_trace_rq_issue);
- WARN_ON(ret);
- ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue);
- WARN_ON(ret);
- ret = register_trace_block_rq_complete(blk_add_trace_rq_complete);
- WARN_ON(ret);
- ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce);
- WARN_ON(ret);
- ret = register_trace_block_bio_complete(blk_add_trace_bio_complete);
- WARN_ON(ret);
- ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge);
- WARN_ON(ret);
- ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge);
- WARN_ON(ret);
- ret = register_trace_block_bio_queue(blk_add_trace_bio_queue);
- WARN_ON(ret);
- ret = register_trace_block_getrq(blk_add_trace_getrq);
- WARN_ON(ret);
- ret = register_trace_block_sleeprq(blk_add_trace_sleeprq);
- WARN_ON(ret);
- ret = register_trace_block_plug(blk_add_trace_plug);
- WARN_ON(ret);
- ret = register_trace_block_unplug_timer(blk_add_trace_unplug_timer);
- WARN_ON(ret);
- ret = register_trace_block_unplug_io(blk_add_trace_unplug_io);
- WARN_ON(ret);
- ret = register_trace_block_split(blk_add_trace_split);
- WARN_ON(ret);
- ret = register_trace_block_remap(blk_add_trace_remap);
- WARN_ON(ret);
- return 0;
-}
-
-static void blk_unregister_tracepoints(void)
-{
- unregister_trace_block_remap(blk_add_trace_remap);
- unregister_trace_block_split(blk_add_trace_split);
- unregister_trace_block_unplug_io(blk_add_trace_unplug_io);
- unregister_trace_block_unplug_timer(blk_add_trace_unplug_timer);
- unregister_trace_block_plug(blk_add_trace_plug);
- unregister_trace_block_sleeprq(blk_add_trace_sleeprq);
- unregister_trace_block_getrq(blk_add_trace_getrq);
- unregister_trace_block_bio_queue(blk_add_trace_bio_queue);
- unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge);
- unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge);
- unregister_trace_block_bio_complete(blk_add_trace_bio_complete);
- unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce);
- unregister_trace_block_rq_complete(blk_add_trace_rq_complete);
- unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue);
- unregister_trace_block_rq_issue(blk_add_trace_rq_issue);
- unregister_trace_block_rq_insert(blk_add_trace_rq_insert);
- unregister_trace_block_rq_abort(blk_add_trace_rq_abort);
-
- tracepoint_synchronize_unregister();
-}
-
-/*
- * struct blk_io_tracer formatting routines
- */
-
-static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
-{
- int i = 0;
-
- if (t->action & BLK_TC_DISCARD)
- rwbs[i++] = 'D';
- else if (t->action & BLK_TC_WRITE)
- rwbs[i++] = 'W';
- else if (t->bytes)
- rwbs[i++] = 'R';
- else
- rwbs[i++] = 'N';
-
- if (t->action & BLK_TC_AHEAD)
- rwbs[i++] = 'A';
- if (t->action & BLK_TC_BARRIER)
- rwbs[i++] = 'B';
- if (t->action & BLK_TC_SYNC)
- rwbs[i++] = 'S';
- if (t->action & BLK_TC_META)
- rwbs[i++] = 'M';
-
- rwbs[i] = '\0';
-}
-
-static inline
-const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent)
-{
- return (const struct blk_io_trace *)ent;
-}
-
-static inline const void *pdu_start(const struct trace_entry *ent)
-{
- return te_blk_io_trace(ent) + 1;
-}
-
-static inline u32 t_sec(const struct trace_entry *ent)
-{
- return te_blk_io_trace(ent)->bytes >> 9;
-}
-
-static inline unsigned long long t_sector(const struct trace_entry *ent)
-{
- return te_blk_io_trace(ent)->sector;
-}
-
-static inline __u16 t_error(const struct trace_entry *ent)
-{
- return te_blk_io_trace(ent)->sector;
-}
-
-static __u64 get_pdu_int(const struct trace_entry *ent)
-{
- const __u64 *val = pdu_start(ent);
- return be64_to_cpu(*val);
-}
-
-static void get_pdu_remap(const struct trace_entry *ent,
- struct blk_io_trace_remap *r)
-{
- const struct blk_io_trace_remap *__r = pdu_start(ent);
- __u64 sector = __r->sector;
-
- r->device = be32_to_cpu(__r->device);
- r->device_from = be32_to_cpu(__r->device_from);
- r->sector = be64_to_cpu(sector);
-}
-
-static int blk_log_action_iter(struct trace_iterator *iter, const char *act)
-{
- char rwbs[6];
- unsigned long long ts = ns2usecs(iter->ts);
- unsigned long usec_rem = do_div(ts, USEC_PER_SEC);
- unsigned secs = (unsigned long)ts;
- const struct trace_entry *ent = iter->ent;
- const struct blk_io_trace *t = (const struct blk_io_trace *)ent;
-
- fill_rwbs(rwbs, t);
-
- return trace_seq_printf(&iter->seq,
- "%3d,%-3d %2d %5d.%06lu %5u %2s %3s ",
- MAJOR(t->device), MINOR(t->device), iter->cpu,
- secs, usec_rem, ent->pid, act, rwbs);
-}
-
-static int blk_log_action_seq(struct trace_seq *s, const struct blk_io_trace *t,
- const char *act)
-{
- char rwbs[6];
- fill_rwbs(rwbs, t);
- return trace_seq_printf(s, "%3d,%-3d %2s %3s ",
- MAJOR(t->device), MINOR(t->device), act, rwbs);
-}
-
-static int blk_log_generic(struct trace_seq *s, const struct trace_entry *ent)
-{
- const char *cmd = trace_find_cmdline(ent->pid);
-
- if (t_sec(ent))
- return trace_seq_printf(s, "%llu + %u [%s]\n",
- t_sector(ent), t_sec(ent), cmd);
- return trace_seq_printf(s, "[%s]\n", cmd);
-}
-
-static int blk_log_with_error(struct trace_seq *s,
- const struct trace_entry *ent)
-{
- if (t_sec(ent))
- return trace_seq_printf(s, "%llu + %u [%d]\n", t_sector(ent),
- t_sec(ent), t_error(ent));
- return trace_seq_printf(s, "%llu [%d]\n", t_sector(ent), t_error(ent));
-}
-
-static int blk_log_remap(struct trace_seq *s, const struct trace_entry *ent)
-{
- struct blk_io_trace_remap r = { .device = 0, };
-
- get_pdu_remap(ent, &r);
- return trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
- t_sector(ent),
- t_sec(ent), MAJOR(r.device), MINOR(r.device),
- (unsigned long long)r.sector);
-}
-
-static int blk_log_plug(struct trace_seq *s, const struct trace_entry *ent)
-{
- return trace_seq_printf(s, "[%s]\n", trace_find_cmdline(ent->pid));
-}
-
-static int blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent)
-{
- return trace_seq_printf(s, "[%s] %llu\n", trace_find_cmdline(ent->pid),
- get_pdu_int(ent));
-}
-
-static int blk_log_split(struct trace_seq *s, const struct trace_entry *ent)
-{
- return trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
- get_pdu_int(ent), trace_find_cmdline(ent->pid));
-}
-
-/*
- * struct tracer operations
- */
-
-static void blk_tracer_print_header(struct seq_file *m)
-{
- if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
- return;
- seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n"
- "# | | | | | |\n");
-}
-
-static void blk_tracer_start(struct trace_array *tr)
-{
- mutex_lock(&blk_probe_mutex);
- if (atomic_add_return(1, &blk_probes_ref) == 1)
- if (blk_register_tracepoints())
- atomic_dec(&blk_probes_ref);
- mutex_unlock(&blk_probe_mutex);
- trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
-}
-
-static int blk_tracer_init(struct trace_array *tr)
-{
- blk_tr = tr;
- blk_tracer_start(tr);
- mutex_lock(&blk_probe_mutex);
- blk_tracer_enabled++;
- mutex_unlock(&blk_probe_mutex);
- return 0;
-}
-
-static void blk_tracer_stop(struct trace_array *tr)
-{
- trace_flags |= TRACE_ITER_CONTEXT_INFO;
- mutex_lock(&blk_probe_mutex);
- if (atomic_dec_and_test(&blk_probes_ref))
- blk_unregister_tracepoints();
- mutex_unlock(&blk_probe_mutex);
-}
-
-static void blk_tracer_reset(struct trace_array *tr)
-{
- if (!atomic_read(&blk_probes_ref))
- return;
-
- mutex_lock(&blk_probe_mutex);
- blk_tracer_enabled--;
- WARN_ON(blk_tracer_enabled < 0);
- mutex_unlock(&blk_probe_mutex);
-
- blk_tracer_stop(tr);
-}
-
-static struct {
- const char *act[2];
- int (*print)(struct trace_seq *s, const struct trace_entry *ent);
-} what2act[] __read_mostly = {
- [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic },
- [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic },
- [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic },
- [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic },
- [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic },
- [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error },
- [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic },
- [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error },
- [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug },
- [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug },
- [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug },
- [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic },
- [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split },
- [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic },
- [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap },
-};
-
-static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
- int flags)
-{
- struct trace_seq *s = &iter->seq;
- const struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
- const u16 what = t->action & ((1 << BLK_TC_SHIFT) - 1);
- int ret;
-
- if (!trace_print_context(iter))
- return TRACE_TYPE_PARTIAL_LINE;
-
- if (unlikely(what == 0 || what > ARRAY_SIZE(what2act)))
- ret = trace_seq_printf(s, "Bad pc action %x\n", what);
- else {
- const bool long_act = !!(trace_flags & TRACE_ITER_VERBOSE);
- ret = blk_log_action_seq(s, t, what2act[what].act[long_act]);
- if (ret)
- ret = what2act[what].print(s, iter->ent);
- }
-
- return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
-}
-
-static int blk_trace_synthesize_old_trace(struct trace_iterator *iter)
-{
- struct trace_seq *s = &iter->seq;
- struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
- const int offset = offsetof(struct blk_io_trace, sector);
- struct blk_io_trace old = {
- .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
- .time = ns2usecs(iter->ts),
- };
-
- if (!trace_seq_putmem(s, &old, offset))
- return 0;
- return trace_seq_putmem(s, &t->sector,
- sizeof(old) - offset + t->pdu_len);
-}
-
-static enum print_line_t
-blk_trace_event_print_binary(struct trace_iterator *iter, int flags)
-{
- return blk_trace_synthesize_old_trace(iter) ?
- TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
-}
-
-static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
-{
- const struct blk_io_trace *t;
- u16 what;
- int ret;
-
- if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
- return TRACE_TYPE_UNHANDLED;
-
- t = (const struct blk_io_trace *)iter->ent;
- what = t->action & ((1 << BLK_TC_SHIFT) - 1);
-
- if (unlikely(what == 0 || what > ARRAY_SIZE(what2act)))
- ret = trace_seq_printf(&iter->seq, "Bad pc action %x\n", what);
- else {
- const bool long_act = !!(trace_flags & TRACE_ITER_VERBOSE);
- ret = blk_log_action_iter(iter, what2act[what].act[long_act]);
- if (ret)
- ret = what2act[what].print(&iter->seq, iter->ent);
- }
-
- return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
-}
-
-static struct tracer blk_tracer __read_mostly = {
- .name = "blk",
- .init = blk_tracer_init,
- .reset = blk_tracer_reset,
- .start = blk_tracer_start,
- .stop = blk_tracer_stop,
- .print_header = blk_tracer_print_header,
- .print_line = blk_tracer_print_line,
- .flags = &blk_tracer_flags,
-};
-
-static struct trace_event trace_blk_event = {
- .type = TRACE_BLK,
- .trace = blk_trace_event_print,
- .latency_trace = blk_trace_event_print,
- .binary = blk_trace_event_print_binary,
-};
-
-static int __init init_blk_tracer(void)
-{
- if (!register_ftrace_event(&trace_blk_event)) {
- pr_warning("Warning: could not register block events\n");
- return 1;
- }
-
- if (register_tracer(&blk_tracer) != 0) {
- pr_warning("Warning: could not register the block tracer\n");
- unregister_ftrace_event(&trace_blk_event);
- return 1;
- }
-
- return 0;
-}
-
-device_initcall(init_blk_tracer);
-
-static int blk_trace_remove_queue(struct request_queue *q)
-{
- struct blk_trace *bt;
-
- bt = xchg(&q->blk_trace, NULL);
- if (bt == NULL)
- return -EINVAL;
-
- kfree(bt);
- return 0;
-}
-
-/*
- * Setup everything required to start tracing
- */
-static int blk_trace_setup_queue(struct request_queue *q, dev_t dev)
-{
- struct blk_trace *old_bt, *bt = NULL;
- int ret;
-
- ret = -ENOMEM;
- bt = kzalloc(sizeof(*bt), GFP_KERNEL);
- if (!bt)
- goto err;
-
- bt->dev = dev;
- bt->act_mask = (u16)-1;
- bt->end_lba = -1ULL;
- bt->trace_state = Blktrace_running;
-
- old_bt = xchg(&q->blk_trace, bt);
- if (old_bt != NULL) {
- (void)xchg(&q->blk_trace, old_bt);
- kfree(bt);
- ret = -EBUSY;
- }
- return 0;
-err:
- return ret;
-}
-
-/*
- * sysfs interface to enable and configure tracing
- */
-
-static ssize_t sysfs_blk_trace_enable_show(struct device *dev,
- struct device_attribute *attr,
- char *buf)
-{
- struct hd_struct *p = dev_to_part(dev);
- struct block_device *bdev;
- ssize_t ret = -ENXIO;
-
- lock_kernel();
- bdev = bdget(part_devt(p));
- if (bdev != NULL) {
- struct request_queue *q = bdev_get_queue(bdev);
-
- if (q != NULL) {
- mutex_lock(&bdev->bd_mutex);
- ret = sprintf(buf, "%u\n", !!q->blk_trace);
- mutex_unlock(&bdev->bd_mutex);
- }
-
- bdput(bdev);
- }
-
- unlock_kernel();
- return ret;
-}
-
-static ssize_t sysfs_blk_trace_enable_store(struct device *dev,
- struct device_attribute *attr,
- const char *buf, size_t count)
-{
- struct block_device *bdev;
- struct request_queue *q;
- struct hd_struct *p;
- int value;
- ssize_t ret = -ENXIO;
-
- if (count == 0 || sscanf(buf, "%d", &value) != 1)
- goto out;
-
- lock_kernel();
- p = dev_to_part(dev);
- bdev = bdget(part_devt(p));
- if (bdev == NULL)
- goto out_unlock_kernel;
-
- q = bdev_get_queue(bdev);
- if (q == NULL)
- goto out_bdput;
-
- mutex_lock(&bdev->bd_mutex);
- if (value)
- ret = blk_trace_setup_queue(q, bdev->bd_dev);
- else
- ret = blk_trace_remove_queue(q);
- mutex_unlock(&bdev->bd_mutex);
-
- if (ret == 0)
- ret = count;
-out_bdput:
- bdput(bdev);
-out_unlock_kernel:
- unlock_kernel();
-out:
- return ret;
-}
-
-static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
- struct device_attribute *attr,
- char *buf);
-static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
- struct device_attribute *attr,
- const char *buf, size_t count);
-#define BLK_TRACE_DEVICE_ATTR(_name) \
- DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
- sysfs_blk_trace_attr_show, \
- sysfs_blk_trace_attr_store)
-
-static DEVICE_ATTR(enable, S_IRUGO | S_IWUSR,
- sysfs_blk_trace_enable_show, sysfs_blk_trace_enable_store);
-static BLK_TRACE_DEVICE_ATTR(act_mask);
-static BLK_TRACE_DEVICE_ATTR(pid);
-static BLK_TRACE_DEVICE_ATTR(start_lba);
-static BLK_TRACE_DEVICE_ATTR(end_lba);
-
-static struct attribute *blk_trace_attrs[] = {
- &dev_attr_enable.attr,
- &dev_attr_act_mask.attr,
- &dev_attr_pid.attr,
- &dev_attr_start_lba.attr,
- &dev_attr_end_lba.attr,
- NULL
-};
-
-struct attribute_group blk_trace_attr_group = {
- .name = "trace",
- .attrs = blk_trace_attrs,
-};
-
-static int blk_str2act_mask(const char *str)
-{
- int mask = 0;
- char *copy = kstrdup(str, GFP_KERNEL), *s;
-
- if (copy == NULL)
- return -ENOMEM;
-
- s = strstrip(copy);
-
- while (1) {
- char *sep = strchr(s, ',');
-
- if (sep != NULL)
- *sep = '\0';
-
- if (strcasecmp(s, "barrier") == 0)
- mask |= BLK_TC_BARRIER;
- else if (strcasecmp(s, "complete") == 0)
- mask |= BLK_TC_COMPLETE;
- else if (strcasecmp(s, "fs") == 0)
- mask |= BLK_TC_FS;
- else if (strcasecmp(s, "issue") == 0)
- mask |= BLK_TC_ISSUE;
- else if (strcasecmp(s, "pc") == 0)
- mask |= BLK_TC_PC;
- else if (strcasecmp(s, "queue") == 0)
- mask |= BLK_TC_QUEUE;
- else if (strcasecmp(s, "read") == 0)
- mask |= BLK_TC_READ;
- else if (strcasecmp(s, "requeue") == 0)
- mask |= BLK_TC_REQUEUE;
- else if (strcasecmp(s, "sync") == 0)
- mask |= BLK_TC_SYNC;
- else if (strcasecmp(s, "write") == 0)
- mask |= BLK_TC_WRITE;
-
- if (sep == NULL)
- break;
-
- s = sep + 1;
- }
- kfree(copy);
-
- return mask;
-}
-
-static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
- struct device_attribute *attr,
- char *buf)
-{
- struct hd_struct *p = dev_to_part(dev);
- struct request_queue *q;
- struct block_device *bdev;
- ssize_t ret = -ENXIO;
-
- lock_kernel();
- bdev = bdget(part_devt(p));
- if (bdev == NULL)
- goto out_unlock_kernel;
-
- q = bdev_get_queue(bdev);
- if (q == NULL)
- goto out_bdput;
- mutex_lock(&bdev->bd_mutex);
- if (q->blk_trace == NULL)
- ret = sprintf(buf, "disabled\n");
- else if (attr == &dev_attr_act_mask)
- ret = sprintf(buf, "%#x\n", q->blk_trace->act_mask);
- else if (attr == &dev_attr_pid)
- ret = sprintf(buf, "%u\n", q->blk_trace->pid);
- else if (attr == &dev_attr_start_lba)
- ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba);
- else if (attr == &dev_attr_end_lba)
- ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba);
- mutex_unlock(&bdev->bd_mutex);
-out_bdput:
- bdput(bdev);
-out_unlock_kernel:
- unlock_kernel();
- return ret;
-}
-
-static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
- struct device_attribute *attr,
- const char *buf, size_t count)
-{
- struct block_device *bdev;
- struct request_queue *q;
- struct hd_struct *p;
- u64 value;
- ssize_t ret = -ENXIO;
-
- if (count == 0)
- goto out;
-
- if (attr == &dev_attr_act_mask) {
- if (sscanf(buf, "%llx", &value) != 1) {
- /* Assume it is a list of trace category names */
- value = blk_str2act_mask(buf);
- if (value < 0)
- goto out;
- }
- } else if (sscanf(buf, "%llu", &value) != 1)
- goto out;
-
- lock_kernel();
- p = dev_to_part(dev);
- bdev = bdget(part_devt(p));
- if (bdev == NULL)
- goto out_unlock_kernel;
-
- q = bdev_get_queue(bdev);
- if (q == NULL)
- goto out_bdput;
-
- mutex_lock(&bdev->bd_mutex);
- ret = 0;
- if (q->blk_trace == NULL)
- ret = blk_trace_setup_queue(q, bdev->bd_dev);
-
- if (ret == 0) {
- if (attr == &dev_attr_act_mask)
- q->blk_trace->act_mask = value;
- else if (attr == &dev_attr_pid)
- q->blk_trace->pid = value;
- else if (attr == &dev_attr_start_lba)
- q->blk_trace->start_lba = value;
- else if (attr == &dev_attr_end_lba)
- q->blk_trace->end_lba = value;
- ret = count;
- }
- mutex_unlock(&bdev->bd_mutex);
-out_bdput:
- bdput(bdev);
-out_unlock_kernel:
- unlock_kernel();
-out:
- return ret;
-}
For example it can help a developer to decide whether he should
choose a per cpu workqueue instead of a singlethreaded one.
+config BLK_DEV_IO_TRACE
+ bool "Support for tracing block io actions"
+ depends on SYSFS
+ select RELAY
+ select DEBUG_FS
+ select TRACEPOINTS
+ select TRACING
+ select STACKTRACE
+ help
+ Say Y here if you want to be able to trace the block layer actions
+ on a given queue. Tracing allows you to see any traffic happening
+ on a block device queue. For more information (and the userspace
+ support tools needed), fetch the blktrace tools from:
+
+ git://git.kernel.dk/blktrace.git
+
+ Tracing also is possible using the ftrace interface, e.g.:
+
+ echo 1 > /sys/block/sda/sda1/trace/enable
+ echo blk > /sys/kernel/debug/tracing/current_tracer
+ cat /sys/kernel/debug/tracing/trace_pipe
+
+ If unsure, say N.
config DYNAMIC_FTRACE
bool "enable/disable ftrace tracepoints dynamically"
obj-$(CONFIG_POWER_TRACER) += trace_power.o
obj-$(CONFIG_KMEMTRACE) += kmemtrace.o
obj-$(CONFIG_WORKQUEUE_TRACER) += trace_workqueue.o
+obj-$(CONFIG_BLK_DEV_IO_TRACE) += blktrace.o
libftrace-y := ftrace.o
--- /dev/null
+/*
+ * Copyright (C) 2006 Jens Axboe <axboe@kernel.dk>
+ *
+ * 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/debugfs.h>
+#include <linux/time.h>
+#include <trace/block.h>
+#include <linux/uaccess.h>
+#include "trace_output.h"
+
+static unsigned int blktrace_seq __read_mostly = 1;
+
+static struct trace_array *blk_tr;
+static int __read_mostly blk_tracer_enabled;
+
+/* 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 DEFINE_MUTEX(blk_probe_mutex);
+static atomic_t blk_probes_ref = ATOMIC_INIT(0);
+
+static int 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;
+
+ if (!bt->rchan)
+ return;
+
+ t = relay_reserve(bt->rchan, sizeof(*t) + len);
+ if (t) {
+ const int cpu = smp_processor_id();
+
+ t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
+ t->time = ktime_to_ns(ktime_get());
+ t->device = bt->dev;
+ t->action = action;
+ t->pid = pid;
+ t->cpu = cpu;
+ t->pdu_len = len;
+ memcpy((void *) t + sizeof(*t), data, len);
+ }
+}
+
+/*
+ * Send out a notify for this process, if we haven't done so since a trace
+ * started
+ */
+static void trace_note_tsk(struct blk_trace *bt, struct task_struct *tsk)
+{
+ tsk->btrace_seq = blktrace_seq;
+ trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm, sizeof(tsk->comm));
+}
+
+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 (blk_tr) {
+ va_start(args, fmt);
+ ftrace_vprintk(fmt, args);
+ va_end(args);
+ return;
+ }
+
+ if (!bt->msg_data)
+ return;
+
+ local_irq_save(flags);
+ buf = per_cpu_ptr(bt->msg_data, smp_processor_id());
+ 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 < bt->start_lba || sector > bt->end_lba)
+ return 1;
+ if (bt->pid && pid != bt->pid)
+ return 1;
+
+ return 0;
+}
+
+/*
+ * Data direction bit lookup
+ */
+static u32 ddir_act[2] __read_mostly = { BLK_TC_ACT(BLK_TC_READ),
+ BLK_TC_ACT(BLK_TC_WRITE) };
+
+/* The ilog2() calls fall out because they're constant */
+#define MASK_TC_BIT(rw, __name) ((rw & (1 << BIO_RW_ ## __name)) << \
+ (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - BIO_RW_ ## __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 blk_io_trace *t;
+ unsigned long flags = 0;
+ unsigned long *sequence;
+ pid_t pid;
+ int cpu, pc = 0;
+
+ if (unlikely(bt->trace_state != Blktrace_running ||
+ !blk_tracer_enabled))
+ return;
+
+ what |= ddir_act[rw & WRITE];
+ what |= MASK_TC_BIT(rw, BARRIER);
+ what |= MASK_TC_BIT(rw, SYNC);
+ what |= MASK_TC_BIT(rw, AHEAD);
+ what |= MASK_TC_BIT(rw, META);
+ what |= MASK_TC_BIT(rw, DISCARD);
+
+ pid = tsk->pid;
+ if (unlikely(act_log_check(bt, what, sector, pid)))
+ return;
+ cpu = raw_smp_processor_id();
+
+ if (blk_tr) {
+ tracing_record_cmdline(current);
+
+ pc = preempt_count();
+ event = trace_buffer_lock_reserve(blk_tr, TRACE_BLK,
+ sizeof(*t) + pdu_len,
+ 0, pc);
+ if (!event)
+ return;
+ t = ring_buffer_event_data(event);
+ goto record_it;
+ }
+
+ /*
+ * 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);
+
+ if (unlikely(tsk->btrace_seq != blktrace_seq))
+ trace_note_tsk(bt, tsk);
+
+ 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_tr) {
+ trace_buffer_unlock_commit(blk_tr, event, 0, pc);
+ return;
+ }
+ }
+
+ local_irq_restore(flags);
+}
+
+static struct dentry *blk_tree_root;
+static DEFINE_MUTEX(blk_tree_mutex);
+
+static void blk_trace_cleanup(struct blk_trace *bt)
+{
+ debugfs_remove(bt->msg_file);
+ debugfs_remove(bt->dropped_file);
+ relay_close(bt->rchan);
+ free_percpu(bt->sequence);
+ free_percpu(bt->msg_data);
+ kfree(bt);
+ mutex_lock(&blk_probe_mutex);
+ if (atomic_dec_and_test(&blk_probes_ref))
+ blk_unregister_tracepoints();
+ mutex_unlock(&blk_probe_mutex);
+}
+
+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_setup ||
+ bt->trace_state == Blktrace_stopped)
+ blk_trace_cleanup(bt);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(blk_trace_remove);
+
+static int blk_dropped_open(struct inode *inode, struct file *filp)
+{
+ filp->private_data = inode->i_private;
+
+ return 0;
+}
+
+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 = blk_dropped_open,
+ .read = blk_dropped_read,
+};
+
+static int blk_msg_open(struct inode *inode, struct file *filp)
+{
+ filp->private_data = inode->i_private;
+
+ return 0;
+}
+
+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 = kmalloc(count, GFP_KERNEL);
+ if (msg == NULL)
+ return -ENOMEM;
+
+ if (copy_from_user(msg, buffer, count)) {
+ kfree(msg);
+ return -EFAULT;
+ }
+
+ 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 = blk_msg_open,
+ .write = blk_msg_write,
+};
+
+/*
+ * 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)
+{
+ struct dentry *parent = dentry->d_parent;
+ debugfs_remove(dentry);
+
+ /*
+ * this will fail for all but the last file, but that is ok. what we
+ * care about is the top level buts->name directory going away, when
+ * the last trace file is gone. Then we don't have to rmdir() that
+ * manually on trace stop, so it nicely solves the issue with
+ * force killing of running traces.
+ */
+
+ debugfs_remove(parent);
+ return 0;
+}
+
+static struct dentry *blk_create_buf_file_callback(const char *filename,
+ struct dentry *parent,
+ int 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,
+};
+
+/*
+ * Setup everything required to start tracing
+ */
+int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
+ struct blk_user_trace_setup *buts)
+{
+ struct blk_trace *old_bt, *bt = NULL;
+ struct dentry *dir = NULL;
+ int ret, i;
+
+ 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
+ */
+ for (i = 0; i < strlen(buts->name); i++)
+ if (buts->name[i] == '/')
+ buts->name[i] = '_';
+
+ ret = -ENOMEM;
+ bt = kzalloc(sizeof(*bt), GFP_KERNEL);
+ if (!bt)
+ goto err;
+
+ bt->sequence = alloc_percpu(unsigned long);
+ if (!bt->sequence)
+ goto err;
+
+ bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG);
+ if (!bt->msg_data)
+ goto err;
+
+ ret = -ENOENT;
+
+ if (!blk_tree_root) {
+ blk_tree_root = debugfs_create_dir("block", NULL);
+ if (!blk_tree_root)
+ return -ENOMEM;
+ }
+
+ dir = debugfs_create_dir(buts->name, blk_tree_root);
+
+ if (!dir)
+ goto err;
+
+ bt->dir = dir;
+ bt->dev = dev;
+ atomic_set(&bt->dropped, 0);
+
+ 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;
+
+ bt->start_lba = buts->start_lba;
+ bt->end_lba = buts->end_lba;
+ if (!bt->end_lba)
+ bt->end_lba = -1ULL;
+
+ bt->pid = buts->pid;
+ bt->trace_state = Blktrace_setup;
+
+ mutex_lock(&blk_probe_mutex);
+ if (atomic_add_return(1, &blk_probes_ref) == 1) {
+ ret = blk_register_tracepoints();
+ if (ret)
+ goto probe_err;
+ }
+ mutex_unlock(&blk_probe_mutex);
+
+ ret = -EBUSY;
+ old_bt = xchg(&q->blk_trace, bt);
+ if (old_bt) {
+ (void) xchg(&q->blk_trace, old_bt);
+ goto err;
+ }
+
+ return 0;
+probe_err:
+ atomic_dec(&blk_probes_ref);
+ mutex_unlock(&blk_probe_mutex);
+err:
+ if (bt) {
+ if (bt->msg_file)
+ debugfs_remove(bt->msg_file);
+ if (bt->dropped_file)
+ debugfs_remove(bt->dropped_file);
+ free_percpu(bt->sequence);
+ free_percpu(bt->msg_data);
+ if (bt->rchan)
+ relay_close(bt->rchan);
+ kfree(bt);
+ }
+ return ret;
+}
+
+int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
+ 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, &buts);
+ if (ret)
+ return ret;
+
+ if (copy_to_user(arg, &buts, sizeof(buts)))
+ return -EFAULT;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(blk_trace_setup);
+
+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;
+
+ trace_note_time(bt);
+ ret = 0;
+ }
+ } else {
+ if (bt->trace_state == Blktrace_running) {
+ bt->trace_state = Blktrace_stopped;
+ 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, arg);
+ break;
+ 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
+ * @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,
+ u32 what)
+{
+ struct blk_trace *bt = q->blk_trace;
+ int rw = rq->cmd_flags & 0x03;
+
+ if (likely(!bt))
+ return;
+
+ if (blk_discard_rq(rq))
+ rw |= (1 << BIO_RW_DISCARD);
+
+ if (blk_pc_request(rq)) {
+ what |= BLK_TC_ACT(BLK_TC_PC);
+ __blk_add_trace(bt, 0, rq->data_len, rw, what, rq->errors,
+ sizeof(rq->cmd), rq->cmd);
+ } else {
+ what |= BLK_TC_ACT(BLK_TC_FS);
+ __blk_add_trace(bt, rq->hard_sector, rq->hard_nr_sectors << 9,
+ rw, what, rq->errors, 0, NULL);
+ }
+}
+
+static void blk_add_trace_rq_abort(struct request_queue *q, struct request *rq)
+{
+ blk_add_trace_rq(q, rq, BLK_TA_ABORT);
+}
+
+static void blk_add_trace_rq_insert(struct request_queue *q, struct request *rq)
+{
+ blk_add_trace_rq(q, rq, BLK_TA_INSERT);
+}
+
+static void blk_add_trace_rq_issue(struct request_queue *q, struct request *rq)
+{
+ blk_add_trace_rq(q, rq, BLK_TA_ISSUE);
+}
+
+static void blk_add_trace_rq_requeue(struct request_queue *q,
+ struct request *rq)
+{
+ blk_add_trace_rq(q, rq, BLK_TA_REQUEUE);
+}
+
+static void blk_add_trace_rq_complete(struct request_queue *q,
+ struct request *rq)
+{
+ blk_add_trace_rq(q, rq, 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
+ *
+ * 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)
+{
+ struct blk_trace *bt = q->blk_trace;
+
+ if (likely(!bt))
+ return;
+
+ __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, what,
+ !bio_flagged(bio, BIO_UPTODATE), 0, NULL);
+}
+
+static void blk_add_trace_bio_bounce(struct request_queue *q, struct bio *bio)
+{
+ blk_add_trace_bio(q, bio, BLK_TA_BOUNCE);
+}
+
+static void blk_add_trace_bio_complete(struct request_queue *q, struct bio *bio)
+{
+ blk_add_trace_bio(q, bio, BLK_TA_COMPLETE);
+}
+
+static void blk_add_trace_bio_backmerge(struct request_queue *q,
+ struct bio *bio)
+{
+ blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE);
+}
+
+static void blk_add_trace_bio_frontmerge(struct request_queue *q,
+ struct bio *bio)
+{
+ blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE);
+}
+
+static void blk_add_trace_bio_queue(struct request_queue *q, struct bio *bio)
+{
+ blk_add_trace_bio(q, bio, BLK_TA_QUEUE);
+}
+
+static void blk_add_trace_getrq(struct request_queue *q,
+ struct bio *bio, int rw)
+{
+ if (bio)
+ blk_add_trace_bio(q, bio, BLK_TA_GETRQ);
+ 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(struct request_queue *q,
+ struct bio *bio, int rw)
+{
+ if (bio)
+ blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ);
+ 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(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_io(struct request_queue *q)
+{
+ struct blk_trace *bt = q->blk_trace;
+
+ if (bt) {
+ unsigned int pdu = q->rq.count[READ] + q->rq.count[WRITE];
+ __be64 rpdu = cpu_to_be64(pdu);
+
+ __blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_IO, 0,
+ sizeof(rpdu), &rpdu);
+ }
+}
+
+static void blk_add_trace_unplug_timer(struct request_queue *q)
+{
+ struct blk_trace *bt = q->blk_trace;
+
+ if (bt) {
+ unsigned int pdu = q->rq.count[READ] + q->rq.count[WRITE];
+ __be64 rpdu = cpu_to_be64(pdu);
+
+ __blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_TIMER, 0,
+ sizeof(rpdu), &rpdu);
+ }
+}
+
+static void blk_add_trace_split(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_sector, bio->bi_size, bio->bi_rw,
+ BLK_TA_SPLIT, !bio_flagged(bio, BIO_UPTODATE),
+ sizeof(rpdu), &rpdu);
+ }
+}
+
+/**
+ * blk_add_trace_remap - Add a trace for a remap operation
+ * @q: queue the io is for
+ * @bio: the source bio
+ * @dev: target device
+ * @from: source sector
+ * @to: target 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_remap(struct request_queue *q, struct bio *bio,
+ dev_t dev, sector_t from, sector_t to)
+{
+ struct blk_trace *bt = q->blk_trace;
+ struct blk_io_trace_remap r;
+
+ if (likely(!bt))
+ return;
+
+ r.device = cpu_to_be32(dev);
+ r.device_from = cpu_to_be32(bio->bi_bdev->bd_dev);
+ r.sector = cpu_to_be64(to);
+
+ __blk_add_trace(bt, from, bio->bi_size, bio->bi_rw, BLK_TA_REMAP,
+ !bio_flagged(bio, BIO_UPTODATE), 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 (blk_pc_request(rq))
+ __blk_add_trace(bt, 0, rq->data_len, 0, BLK_TA_DRV_DATA,
+ rq->errors, len, data);
+ else
+ __blk_add_trace(bt, rq->hard_sector, rq->hard_nr_sectors << 9,
+ 0, BLK_TA_DRV_DATA, rq->errors, len, data);
+}
+EXPORT_SYMBOL_GPL(blk_add_driver_data);
+
+static int blk_register_tracepoints(void)
+{
+ int ret;
+
+ ret = register_trace_block_rq_abort(blk_add_trace_rq_abort);
+ WARN_ON(ret);
+ ret = register_trace_block_rq_insert(blk_add_trace_rq_insert);
+ WARN_ON(ret);
+ ret = register_trace_block_rq_issue(blk_add_trace_rq_issue);
+ WARN_ON(ret);
+ ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue);
+ WARN_ON(ret);
+ ret = register_trace_block_rq_complete(blk_add_trace_rq_complete);
+ WARN_ON(ret);
+ ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce);
+ WARN_ON(ret);
+ ret = register_trace_block_bio_complete(blk_add_trace_bio_complete);
+ WARN_ON(ret);
+ ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge);
+ WARN_ON(ret);
+ ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge);
+ WARN_ON(ret);
+ ret = register_trace_block_bio_queue(blk_add_trace_bio_queue);
+ WARN_ON(ret);
+ ret = register_trace_block_getrq(blk_add_trace_getrq);
+ WARN_ON(ret);
+ ret = register_trace_block_sleeprq(blk_add_trace_sleeprq);
+ WARN_ON(ret);
+ ret = register_trace_block_plug(blk_add_trace_plug);
+ WARN_ON(ret);
+ ret = register_trace_block_unplug_timer(blk_add_trace_unplug_timer);
+ WARN_ON(ret);
+ ret = register_trace_block_unplug_io(blk_add_trace_unplug_io);
+ WARN_ON(ret);
+ ret = register_trace_block_split(blk_add_trace_split);
+ WARN_ON(ret);
+ ret = register_trace_block_remap(blk_add_trace_remap);
+ WARN_ON(ret);
+ return 0;
+}
+
+static void blk_unregister_tracepoints(void)
+{
+ unregister_trace_block_remap(blk_add_trace_remap);
+ unregister_trace_block_split(blk_add_trace_split);
+ unregister_trace_block_unplug_io(blk_add_trace_unplug_io);
+ unregister_trace_block_unplug_timer(blk_add_trace_unplug_timer);
+ unregister_trace_block_plug(blk_add_trace_plug);
+ unregister_trace_block_sleeprq(blk_add_trace_sleeprq);
+ unregister_trace_block_getrq(blk_add_trace_getrq);
+ unregister_trace_block_bio_queue(blk_add_trace_bio_queue);
+ unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge);
+ unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge);
+ unregister_trace_block_bio_complete(blk_add_trace_bio_complete);
+ unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce);
+ unregister_trace_block_rq_complete(blk_add_trace_rq_complete);
+ unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue);
+ unregister_trace_block_rq_issue(blk_add_trace_rq_issue);
+ unregister_trace_block_rq_insert(blk_add_trace_rq_insert);
+ unregister_trace_block_rq_abort(blk_add_trace_rq_abort);
+
+ tracepoint_synchronize_unregister();
+}
+
+/*
+ * struct blk_io_tracer formatting routines
+ */
+
+static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
+{
+ int i = 0;
+
+ if (t->action & BLK_TC_DISCARD)
+ rwbs[i++] = 'D';
+ else if (t->action & BLK_TC_WRITE)
+ rwbs[i++] = 'W';
+ else if (t->bytes)
+ rwbs[i++] = 'R';
+ else
+ rwbs[i++] = 'N';
+
+ if (t->action & BLK_TC_AHEAD)
+ rwbs[i++] = 'A';
+ if (t->action & BLK_TC_BARRIER)
+ rwbs[i++] = 'B';
+ if (t->action & BLK_TC_SYNC)
+ rwbs[i++] = 'S';
+ if (t->action & BLK_TC_META)
+ rwbs[i++] = 'M';
+
+ rwbs[i] = '\0';
+}
+
+static inline
+const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent)
+{
+ return (const struct blk_io_trace *)ent;
+}
+
+static inline const void *pdu_start(const struct trace_entry *ent)
+{
+ return te_blk_io_trace(ent) + 1;
+}
+
+static inline u32 t_sec(const struct trace_entry *ent)
+{
+ return te_blk_io_trace(ent)->bytes >> 9;
+}
+
+static inline unsigned long long t_sector(const struct trace_entry *ent)
+{
+ return te_blk_io_trace(ent)->sector;
+}
+
+static inline __u16 t_error(const struct trace_entry *ent)
+{
+ return te_blk_io_trace(ent)->sector;
+}
+
+static __u64 get_pdu_int(const struct trace_entry *ent)
+{
+ const __u64 *val = pdu_start(ent);
+ return be64_to_cpu(*val);
+}
+
+static void get_pdu_remap(const struct trace_entry *ent,
+ struct blk_io_trace_remap *r)
+{
+ const struct blk_io_trace_remap *__r = pdu_start(ent);
+ __u64 sector = __r->sector;
+
+ r->device = be32_to_cpu(__r->device);
+ r->device_from = be32_to_cpu(__r->device_from);
+ r->sector = be64_to_cpu(sector);
+}
+
+static int blk_log_action_iter(struct trace_iterator *iter, const char *act)
+{
+ char rwbs[6];
+ unsigned long long ts = ns2usecs(iter->ts);
+ unsigned long usec_rem = do_div(ts, USEC_PER_SEC);
+ unsigned secs = (unsigned long)ts;
+ const struct trace_entry *ent = iter->ent;
+ const struct blk_io_trace *t = (const struct blk_io_trace *)ent;
+
+ fill_rwbs(rwbs, t);
+
+ return trace_seq_printf(&iter->seq,
+ "%3d,%-3d %2d %5d.%06lu %5u %2s %3s ",
+ MAJOR(t->device), MINOR(t->device), iter->cpu,
+ secs, usec_rem, ent->pid, act, rwbs);
+}
+
+static int blk_log_action_seq(struct trace_seq *s, const struct blk_io_trace *t,
+ const char *act)
+{
+ char rwbs[6];
+ fill_rwbs(rwbs, t);
+ return trace_seq_printf(s, "%3d,%-3d %2s %3s ",
+ MAJOR(t->device), MINOR(t->device), act, rwbs);
+}
+
+static int blk_log_generic(struct trace_seq *s, const struct trace_entry *ent)
+{
+ const char *cmd = trace_find_cmdline(ent->pid);
+
+ if (t_sec(ent))
+ return trace_seq_printf(s, "%llu + %u [%s]\n",
+ t_sector(ent), t_sec(ent), cmd);
+ return trace_seq_printf(s, "[%s]\n", cmd);
+}
+
+static int blk_log_with_error(struct trace_seq *s,
+ const struct trace_entry *ent)
+{
+ if (t_sec(ent))
+ return trace_seq_printf(s, "%llu + %u [%d]\n", t_sector(ent),
+ t_sec(ent), t_error(ent));
+ return trace_seq_printf(s, "%llu [%d]\n", t_sector(ent), t_error(ent));
+}
+
+static int blk_log_remap(struct trace_seq *s, const struct trace_entry *ent)
+{
+ struct blk_io_trace_remap r = { .device = 0, };
+
+ get_pdu_remap(ent, &r);
+ return trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
+ t_sector(ent),
+ t_sec(ent), MAJOR(r.device), MINOR(r.device),
+ (unsigned long long)r.sector);
+}
+
+static int blk_log_plug(struct trace_seq *s, const struct trace_entry *ent)
+{
+ return trace_seq_printf(s, "[%s]\n", trace_find_cmdline(ent->pid));
+}
+
+static int blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent)
+{
+ return trace_seq_printf(s, "[%s] %llu\n", trace_find_cmdline(ent->pid),
+ get_pdu_int(ent));
+}
+
+static int blk_log_split(struct trace_seq *s, const struct trace_entry *ent)
+{
+ return trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
+ get_pdu_int(ent), trace_find_cmdline(ent->pid));
+}
+
+/*
+ * struct tracer operations
+ */
+
+static void blk_tracer_print_header(struct seq_file *m)
+{
+ if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
+ return;
+ seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n"
+ "# | | | | | |\n");
+}
+
+static void blk_tracer_start(struct trace_array *tr)
+{
+ mutex_lock(&blk_probe_mutex);
+ if (atomic_add_return(1, &blk_probes_ref) == 1)
+ if (blk_register_tracepoints())
+ atomic_dec(&blk_probes_ref);
+ mutex_unlock(&blk_probe_mutex);
+ trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
+}
+
+static int blk_tracer_init(struct trace_array *tr)
+{
+ blk_tr = tr;
+ blk_tracer_start(tr);
+ mutex_lock(&blk_probe_mutex);
+ blk_tracer_enabled++;
+ mutex_unlock(&blk_probe_mutex);
+ return 0;
+}
+
+static void blk_tracer_stop(struct trace_array *tr)
+{
+ trace_flags |= TRACE_ITER_CONTEXT_INFO;
+ mutex_lock(&blk_probe_mutex);
+ if (atomic_dec_and_test(&blk_probes_ref))
+ blk_unregister_tracepoints();
+ mutex_unlock(&blk_probe_mutex);
+}
+
+static void blk_tracer_reset(struct trace_array *tr)
+{
+ if (!atomic_read(&blk_probes_ref))
+ return;
+
+ mutex_lock(&blk_probe_mutex);
+ blk_tracer_enabled--;
+ WARN_ON(blk_tracer_enabled < 0);
+ mutex_unlock(&blk_probe_mutex);
+
+ blk_tracer_stop(tr);
+}
+
+static struct {
+ const char *act[2];
+ int (*print)(struct trace_seq *s, const struct trace_entry *ent);
+} what2act[] __read_mostly = {
+ [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic },
+ [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic },
+ [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic },
+ [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic },
+ [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic },
+ [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error },
+ [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic },
+ [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error },
+ [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug },
+ [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug },
+ [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug },
+ [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic },
+ [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split },
+ [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic },
+ [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap },
+};
+
+static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
+ int flags)
+{
+ struct trace_seq *s = &iter->seq;
+ const struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
+ const u16 what = t->action & ((1 << BLK_TC_SHIFT) - 1);
+ int ret;
+
+ if (!trace_print_context(iter))
+ return TRACE_TYPE_PARTIAL_LINE;
+
+ if (unlikely(what == 0 || what > ARRAY_SIZE(what2act)))
+ ret = trace_seq_printf(s, "Bad pc action %x\n", what);
+ else {
+ const bool long_act = !!(trace_flags & TRACE_ITER_VERBOSE);
+ ret = blk_log_action_seq(s, t, what2act[what].act[long_act]);
+ if (ret)
+ ret = what2act[what].print(s, iter->ent);
+ }
+
+ return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
+}
+
+static int blk_trace_synthesize_old_trace(struct trace_iterator *iter)
+{
+ struct trace_seq *s = &iter->seq;
+ struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
+ const int offset = offsetof(struct blk_io_trace, sector);
+ struct blk_io_trace old = {
+ .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
+ .time = ns2usecs(iter->ts),
+ };
+
+ if (!trace_seq_putmem(s, &old, offset))
+ return 0;
+ return trace_seq_putmem(s, &t->sector,
+ sizeof(old) - offset + t->pdu_len);
+}
+
+static enum print_line_t
+blk_trace_event_print_binary(struct trace_iterator *iter, int flags)
+{
+ return blk_trace_synthesize_old_trace(iter) ?
+ TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
+}
+
+static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
+{
+ const struct blk_io_trace *t;
+ u16 what;
+ int ret;
+
+ if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
+ return TRACE_TYPE_UNHANDLED;
+
+ t = (const struct blk_io_trace *)iter->ent;
+ what = t->action & ((1 << BLK_TC_SHIFT) - 1);
+
+ if (unlikely(what == 0 || what > ARRAY_SIZE(what2act)))
+ ret = trace_seq_printf(&iter->seq, "Bad pc action %x\n", what);
+ else {
+ const bool long_act = !!(trace_flags & TRACE_ITER_VERBOSE);
+ ret = blk_log_action_iter(iter, what2act[what].act[long_act]);
+ if (ret)
+ ret = what2act[what].print(&iter->seq, iter->ent);
+ }
+
+ return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
+}
+
+static struct tracer blk_tracer __read_mostly = {
+ .name = "blk",
+ .init = blk_tracer_init,
+ .reset = blk_tracer_reset,
+ .start = blk_tracer_start,
+ .stop = blk_tracer_stop,
+ .print_header = blk_tracer_print_header,
+ .print_line = blk_tracer_print_line,
+ .flags = &blk_tracer_flags,
+};
+
+static struct trace_event trace_blk_event = {
+ .type = TRACE_BLK,
+ .trace = blk_trace_event_print,
+ .latency_trace = blk_trace_event_print,
+ .binary = blk_trace_event_print_binary,
+};
+
+static int __init init_blk_tracer(void)
+{
+ if (!register_ftrace_event(&trace_blk_event)) {
+ pr_warning("Warning: could not register block events\n");
+ return 1;
+ }
+
+ if (register_tracer(&blk_tracer) != 0) {
+ pr_warning("Warning: could not register the block tracer\n");
+ unregister_ftrace_event(&trace_blk_event);
+ return 1;
+ }
+
+ return 0;
+}
+
+device_initcall(init_blk_tracer);
+
+static int blk_trace_remove_queue(struct request_queue *q)
+{
+ struct blk_trace *bt;
+
+ bt = xchg(&q->blk_trace, NULL);
+ if (bt == NULL)
+ return -EINVAL;
+
+ kfree(bt);
+ return 0;
+}
+
+/*
+ * Setup everything required to start tracing
+ */
+static int blk_trace_setup_queue(struct request_queue *q, dev_t dev)
+{
+ struct blk_trace *old_bt, *bt = NULL;
+ int ret;
+
+ ret = -ENOMEM;
+ bt = kzalloc(sizeof(*bt), GFP_KERNEL);
+ if (!bt)
+ goto err;
+
+ bt->dev = dev;
+ bt->act_mask = (u16)-1;
+ bt->end_lba = -1ULL;
+ bt->trace_state = Blktrace_running;
+
+ old_bt = xchg(&q->blk_trace, bt);
+ if (old_bt != NULL) {
+ (void)xchg(&q->blk_trace, old_bt);
+ kfree(bt);
+ ret = -EBUSY;
+ }
+ return 0;
+err:
+ return ret;
+}
+
+/*
+ * sysfs interface to enable and configure tracing
+ */
+
+static ssize_t sysfs_blk_trace_enable_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct hd_struct *p = dev_to_part(dev);
+ struct block_device *bdev;
+ ssize_t ret = -ENXIO;
+
+ lock_kernel();
+ bdev = bdget(part_devt(p));
+ if (bdev != NULL) {
+ struct request_queue *q = bdev_get_queue(bdev);
+
+ if (q != NULL) {
+ mutex_lock(&bdev->bd_mutex);
+ ret = sprintf(buf, "%u\n", !!q->blk_trace);
+ mutex_unlock(&bdev->bd_mutex);
+ }
+
+ bdput(bdev);
+ }
+
+ unlock_kernel();
+ return ret;
+}
+
+static ssize_t sysfs_blk_trace_enable_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct block_device *bdev;
+ struct request_queue *q;
+ struct hd_struct *p;
+ int value;
+ ssize_t ret = -ENXIO;
+
+ if (count == 0 || sscanf(buf, "%d", &value) != 1)
+ goto out;
+
+ lock_kernel();
+ p = dev_to_part(dev);
+ bdev = bdget(part_devt(p));
+ if (bdev == NULL)
+ goto out_unlock_kernel;
+
+ q = bdev_get_queue(bdev);
+ if (q == NULL)
+ goto out_bdput;
+
+ mutex_lock(&bdev->bd_mutex);
+ if (value)
+ ret = blk_trace_setup_queue(q, bdev->bd_dev);
+ else
+ ret = blk_trace_remove_queue(q);
+ mutex_unlock(&bdev->bd_mutex);
+
+ if (ret == 0)
+ ret = count;
+out_bdput:
+ bdput(bdev);
+out_unlock_kernel:
+ unlock_kernel();
+out:
+ return ret;
+}
+
+static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf);
+static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count);
+#define BLK_TRACE_DEVICE_ATTR(_name) \
+ DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
+ sysfs_blk_trace_attr_show, \
+ sysfs_blk_trace_attr_store)
+
+static DEVICE_ATTR(enable, S_IRUGO | S_IWUSR,
+ sysfs_blk_trace_enable_show, sysfs_blk_trace_enable_store);
+static BLK_TRACE_DEVICE_ATTR(act_mask);
+static BLK_TRACE_DEVICE_ATTR(pid);
+static BLK_TRACE_DEVICE_ATTR(start_lba);
+static BLK_TRACE_DEVICE_ATTR(end_lba);
+
+static struct attribute *blk_trace_attrs[] = {
+ &dev_attr_enable.attr,
+ &dev_attr_act_mask.attr,
+ &dev_attr_pid.attr,
+ &dev_attr_start_lba.attr,
+ &dev_attr_end_lba.attr,
+ NULL
+};
+
+struct attribute_group blk_trace_attr_group = {
+ .name = "trace",
+ .attrs = blk_trace_attrs,
+};
+
+static int blk_str2act_mask(const char *str)
+{
+ int mask = 0;
+ char *copy = kstrdup(str, GFP_KERNEL), *s;
+
+ if (copy == NULL)
+ return -ENOMEM;
+
+ s = strstrip(copy);
+
+ while (1) {
+ char *sep = strchr(s, ',');
+
+ if (sep != NULL)
+ *sep = '\0';
+
+ if (strcasecmp(s, "barrier") == 0)
+ mask |= BLK_TC_BARRIER;
+ else if (strcasecmp(s, "complete") == 0)
+ mask |= BLK_TC_COMPLETE;
+ else if (strcasecmp(s, "fs") == 0)
+ mask |= BLK_TC_FS;
+ else if (strcasecmp(s, "issue") == 0)
+ mask |= BLK_TC_ISSUE;
+ else if (strcasecmp(s, "pc") == 0)
+ mask |= BLK_TC_PC;
+ else if (strcasecmp(s, "queue") == 0)
+ mask |= BLK_TC_QUEUE;
+ else if (strcasecmp(s, "read") == 0)
+ mask |= BLK_TC_READ;
+ else if (strcasecmp(s, "requeue") == 0)
+ mask |= BLK_TC_REQUEUE;
+ else if (strcasecmp(s, "sync") == 0)
+ mask |= BLK_TC_SYNC;
+ else if (strcasecmp(s, "write") == 0)
+ mask |= BLK_TC_WRITE;
+
+ if (sep == NULL)
+ break;
+
+ s = sep + 1;
+ }
+ kfree(copy);
+
+ return mask;
+}
+
+static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct hd_struct *p = dev_to_part(dev);
+ struct request_queue *q;
+ struct block_device *bdev;
+ ssize_t ret = -ENXIO;
+
+ lock_kernel();
+ bdev = bdget(part_devt(p));
+ if (bdev == NULL)
+ goto out_unlock_kernel;
+
+ q = bdev_get_queue(bdev);
+ if (q == NULL)
+ goto out_bdput;
+ mutex_lock(&bdev->bd_mutex);
+ if (q->blk_trace == NULL)
+ ret = sprintf(buf, "disabled\n");
+ else if (attr == &dev_attr_act_mask)
+ ret = sprintf(buf, "%#x\n", q->blk_trace->act_mask);
+ else if (attr == &dev_attr_pid)
+ ret = sprintf(buf, "%u\n", q->blk_trace->pid);
+ else if (attr == &dev_attr_start_lba)
+ ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba);
+ else if (attr == &dev_attr_end_lba)
+ ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba);
+ mutex_unlock(&bdev->bd_mutex);
+out_bdput:
+ bdput(bdev);
+out_unlock_kernel:
+ unlock_kernel();
+ return ret;
+}
+
+static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct block_device *bdev;
+ struct request_queue *q;
+ struct hd_struct *p;
+ u64 value;
+ ssize_t ret = -ENXIO;
+
+ if (count == 0)
+ goto out;
+
+ if (attr == &dev_attr_act_mask) {
+ if (sscanf(buf, "%llx", &value) != 1) {
+ /* Assume it is a list of trace category names */
+ value = blk_str2act_mask(buf);
+ if (value < 0)
+ goto out;
+ }
+ } else if (sscanf(buf, "%llu", &value) != 1)
+ goto out;
+
+ lock_kernel();
+ p = dev_to_part(dev);
+ bdev = bdget(part_devt(p));
+ if (bdev == NULL)
+ goto out_unlock_kernel;
+
+ q = bdev_get_queue(bdev);
+ if (q == NULL)
+ goto out_bdput;
+
+ mutex_lock(&bdev->bd_mutex);
+ ret = 0;
+ if (q->blk_trace == NULL)
+ ret = blk_trace_setup_queue(q, bdev->bd_dev);
+
+ if (ret == 0) {
+ if (attr == &dev_attr_act_mask)
+ q->blk_trace->act_mask = value;
+ else if (attr == &dev_attr_pid)
+ q->blk_trace->pid = value;
+ else if (attr == &dev_attr_start_lba)
+ q->blk_trace->start_lba = value;
+ else if (attr == &dev_attr_end_lba)
+ q->blk_trace->end_lba = value;
+ ret = count;
+ }
+ mutex_unlock(&bdev->bd_mutex);
+out_bdput:
+ bdput(bdev);
+out_unlock_kernel:
+ unlock_kernel();
+out:
+ return ret;
+}
projects / deliverable / linux.git / commitdiff
