v4.19.13 snapshot.
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
new file mode 100644
index 0000000..2868d85
--- /dev/null
+++ b/kernel/trace/blktrace.c
@@ -0,0 +1,1923 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2006 Jens Axboe <axboe@kernel.dk>
+ *
+ */
+#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 <linux/blk-cgroup.h>
+
+#include "../../block/blk.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
+#define TRACE_BLK_OPT_CGROUP 0x2
+#define TRACE_BLK_OPT_CGNAME 0x4
+
+static struct tracer_opt blk_tracer_opts[] = {
+ /* Default disable the minimalistic output */
+ { TRACER_OPT(blk_classic, TRACE_BLK_OPT_CLASSIC) },
+#ifdef CONFIG_BLK_CGROUP
+ { TRACER_OPT(blk_cgroup, TRACE_BLK_OPT_CGROUP) },
+ { TRACER_OPT(blk_cgname, TRACE_BLK_OPT_CGNAME) },
+#endif
+ { }
+};
+
+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 int blk_probes_ref;
+
+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,
+ union kernfs_node_id *cgid)
+{
+ 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;
+ ssize_t cgid_len = cgid ? sizeof(*cgid) : 0;
+
+ if (blk_tracer) {
+ buffer = blk_tr->trace_buffer.buffer;
+ pc = preempt_count();
+ event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
+ sizeof(*t) + len + cgid_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 + cgid_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 | (cgid ? __BLK_TN_CGROUP : 0);
+ t->pid = pid;
+ t->cpu = cpu;
+ t->pdu_len = len + cgid_len;
+ if (cgid)
+ memcpy((void *)t + sizeof(*t), cgid, cgid_len);
+ memcpy((void *) t + sizeof(*t) + cgid_len, 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), NULL);
+ }
+ spin_unlock_irqrestore(&running_trace_lock, flags);
+}
+
+static void trace_note_time(struct blk_trace *bt)
+{
+ struct timespec64 now;
+ unsigned long flags;
+ u32 words[2];
+
+ /* need to check user space to see if this breaks in y2038 or y2106 */
+ ktime_get_real_ts64(&now);
+ words[0] = (u32)now.tv_sec;
+ words[1] = now.tv_nsec;
+
+ local_irq_save(flags);
+ trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words), NULL);
+ local_irq_restore(flags);
+}
+
+void __trace_note_message(struct blk_trace *bt, struct blkcg *blkcg,
+ 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);
+
+ if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP))
+ blkcg = NULL;
+#ifdef CONFIG_BLK_CGROUP
+ trace_note(bt, 0, BLK_TN_MESSAGE, buf, n,
+ blkcg ? cgroup_get_kernfs_id(blkcg->css.cgroup) : NULL);
+#else
+ trace_note(bt, 0, BLK_TN_MESSAGE, buf, n, NULL);
+#endif
+ 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
+#define BLK_TC_PREFLUSH BLK_TC_FLUSH
+
+/* 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 op, int op_flags, u32 what, int error, int pdu_len,
+ void *pdu_data, union kernfs_node_id *cgid)
+{
+ 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;
+ ssize_t cgid_len = cgid ? sizeof(*cgid) : 0;
+
+ if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer))
+ return;
+
+ what |= ddir_act[op_is_write(op) ? WRITE : READ];
+ what |= MASK_TC_BIT(op_flags, SYNC);
+ what |= MASK_TC_BIT(op_flags, RAHEAD);
+ what |= MASK_TC_BIT(op_flags, META);
+ what |= MASK_TC_BIT(op_flags, PREFLUSH);
+ what |= MASK_TC_BIT(op_flags, FUA);
+ if (op == REQ_OP_DISCARD || op == REQ_OP_SECURE_ERASE)
+ what |= BLK_TC_ACT(BLK_TC_DISCARD);
+ if (op == REQ_OP_FLUSH)
+ what |= BLK_TC_ACT(BLK_TC_FLUSH);
+ if (cgid)
+ what |= __BLK_TA_CGROUP;
+
+ 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 + cgid_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 + cgid_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 + cgid_len;
+
+ if (cgid_len)
+ memcpy((void *)t + sizeof(*t), cgid, cgid_len);
+ if (pdu_len)
+ memcpy((void *)t + sizeof(*t) + cgid_len, pdu_data, pdu_len);
+
+ if (blk_tracer) {
+ trace_buffer_unlock_commit(blk_tr, buffer, event, 0, pc);
+ return;
+ }
+ }
+
+ local_irq_restore(flags);
+}
+
+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 get_probe_ref(void)
+{
+ mutex_lock(&blk_probe_mutex);
+ if (++blk_probes_ref == 1)
+ blk_register_tracepoints();
+ mutex_unlock(&blk_probe_mutex);
+}
+
+static void put_probe_ref(void)
+{
+ mutex_lock(&blk_probe_mutex);
+ if (!--blk_probes_ref)
+ blk_unregister_tracepoints();
+ mutex_unlock(&blk_probe_mutex);
+}
+
+static void blk_trace_cleanup(struct blk_trace *bt)
+{
+ blk_trace_free(bt);
+ put_probe_ref();
+}
+
+static 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;
+}
+
+int blk_trace_remove(struct request_queue *q)
+{
+ int ret;
+
+ mutex_lock(&q->blk_trace_mutex);
+ ret = __blk_trace_remove(q);
+ mutex_unlock(&q->blk_trace_mutex);
+
+ return ret;
+}
+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, NULL, "%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
+ */
+static 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;
+
+ if (!blk_debugfs_root)
+ return -ENOENT;
+
+ 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;
+
+ dir = debugfs_lookup(buts->name, blk_debugfs_root);
+ if (!dir)
+ bt->dir = dir = debugfs_create_dir(buts->name, blk_debugfs_root);
+ if (!dir)
+ goto err;
+
+ 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;
+
+ get_probe_ref();
+
+ ret = 0;
+err:
+ if (dir && !bt->dir)
+ dput(dir);
+ if (ret)
+ blk_trace_free(bt);
+ return ret;
+}
+
+static 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;
+}
+
+int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
+ struct block_device *bdev,
+ char __user *arg)
+{
+ int ret;
+
+ mutex_lock(&q->blk_trace_mutex);
+ ret = __blk_trace_setup(q, name, dev, bdev, arg);
+ mutex_unlock(&q->blk_trace_mutex);
+
+ return ret;
+}
+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
+
+static 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;
+}
+
+int blk_trace_startstop(struct request_queue *q, int start)
+{
+ int ret;
+
+ mutex_lock(&q->blk_trace_mutex);
+ ret = __blk_trace_startstop(q, start);
+ mutex_unlock(&q->blk_trace_mutex);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(blk_trace_startstop);
+
+/*
+ * When reading or writing the blktrace sysfs files, the references to the
+ * opened sysfs or device files should prevent the underlying block device
+ * from being removed. So no further delete protection is really needed.
+ */
+
+/**
+ * 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(&q->blk_trace_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(&q->blk_trace_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)
+{
+ mutex_lock(&q->blk_trace_mutex);
+
+ if (q->blk_trace) {
+ __blk_trace_startstop(q, 0);
+ __blk_trace_remove(q);
+ }
+
+ mutex_unlock(&q->blk_trace_mutex);
+}
+
+#ifdef CONFIG_BLK_CGROUP
+static union kernfs_node_id *
+blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio)
+{
+ struct blk_trace *bt = q->blk_trace;
+
+ if (!bt || !(blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP))
+ return NULL;
+
+ if (!bio->bi_css)
+ return NULL;
+ return cgroup_get_kernfs_id(bio->bi_css->cgroup);
+}
+#else
+static union kernfs_node_id *
+blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio)
+{
+ return NULL;
+}
+#endif
+
+static union kernfs_node_id *
+blk_trace_request_get_cgid(struct request_queue *q, struct request *rq)
+{
+ if (!rq->bio)
+ return NULL;
+ /* Use the first bio */
+ return blk_trace_bio_get_cgid(q, rq->bio);
+}
+
+/*
+ * blktrace probes
+ */
+
+/**
+ * blk_add_trace_rq - Add a trace for a request oriented action
+ * @rq: the source request
+ * @error: return status to log
+ * @nr_bytes: number of completed bytes
+ * @what: the action
+ * @cgid: the cgroup info
+ *
+ * Description:
+ * Records an action against a request. Will log the bio offset + size.
+ *
+ **/
+static void blk_add_trace_rq(struct request *rq, int error,
+ unsigned int nr_bytes, u32 what,
+ union kernfs_node_id *cgid)
+{
+ struct blk_trace *bt = rq->q->blk_trace;
+
+ if (likely(!bt))
+ return;
+
+ if (blk_rq_is_passthrough(rq))
+ what |= BLK_TC_ACT(BLK_TC_PC);
+ else
+ what |= BLK_TC_ACT(BLK_TC_FS);
+
+ __blk_add_trace(bt, blk_rq_trace_sector(rq), nr_bytes, req_op(rq),
+ rq->cmd_flags, what, error, 0, NULL, cgid);
+}
+
+static void blk_add_trace_rq_insert(void *ignore,
+ struct request_queue *q, struct request *rq)
+{
+ blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_INSERT,
+ blk_trace_request_get_cgid(q, rq));
+}
+
+static void blk_add_trace_rq_issue(void *ignore,
+ struct request_queue *q, struct request *rq)
+{
+ blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_ISSUE,
+ blk_trace_request_get_cgid(q, rq));
+}
+
+static void blk_add_trace_rq_requeue(void *ignore,
+ struct request_queue *q,
+ struct request *rq)
+{
+ blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_REQUEUE,
+ blk_trace_request_get_cgid(q, rq));
+}
+
+static void blk_add_trace_rq_complete(void *ignore, struct request *rq,
+ int error, unsigned int nr_bytes)
+{
+ blk_add_trace_rq(rq, error, nr_bytes, BLK_TA_COMPLETE,
+ blk_trace_request_get_cgid(rq->q, rq));
+}
+
+/**
+ * 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_op(bio), bio->bi_opf, what, error, 0, NULL,
+ blk_trace_bio_get_cgid(q, bio));
+}
+
+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, 0, BLK_TA_GETRQ, 0, 0,
+ NULL, 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, 0, BLK_TA_SLEEPRQ,
+ 0, 0, NULL, 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, 0, BLK_TA_PLUG, 0, 0, NULL, 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, 0, what, 0, sizeof(rpdu), &rpdu, NULL);
+ }
+}
+
+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_op(bio), bio->bi_opf,
+ BLK_TA_SPLIT, bio->bi_status, sizeof(rpdu),
+ &rpdu, blk_trace_bio_get_cgid(q, bio));
+ }
+}
+
+/**
+ * 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_dev(bio));
+ r.sector_from = cpu_to_be64(from);
+
+ __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
+ bio_op(bio), bio->bi_opf, BLK_TA_REMAP, bio->bi_status,
+ sizeof(r), &r, blk_trace_bio_get_cgid(q, bio));
+}
+
+/**
+ * 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), 0, BLK_TA_REMAP, 0,
+ sizeof(r), &r, blk_trace_request_get_cgid(q, rq));
+}
+
+/**
+ * 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;
+
+ __blk_add_trace(bt, blk_rq_trace_sector(rq), blk_rq_bytes(rq), 0, 0,
+ BLK_TA_DRV_DATA, 0, len, data,
+ blk_trace_request_get_cgid(q, rq));
+}
+EXPORT_SYMBOL_GPL(blk_add_driver_data);
+
+static void blk_register_tracepoints(void)
+{
+ int 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);
+ WARN_ON(ret);
+ ret = register_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
+ WARN_ON(ret);
+ ret = register_trace_block_plug(blk_add_trace_plug, NULL);
+ WARN_ON(ret);
+ ret = register_trace_block_unplug(blk_add_trace_unplug, NULL);
+ WARN_ON(ret);
+ ret = register_trace_block_split(blk_add_trace_split, NULL);
+ WARN_ON(ret);
+ ret = register_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
+ WARN_ON(ret);
+ ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
+ WARN_ON(ret);
+}
+
+static void blk_unregister_tracepoints(void)
+{
+ unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
+ unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
+ unregister_trace_block_split(blk_add_trace_split, NULL);
+ unregister_trace_block_unplug(blk_add_trace_unplug, NULL);
+ unregister_trace_block_plug(blk_add_trace_plug, NULL);
+ unregister_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
+ unregister_trace_block_getrq(blk_add_trace_getrq, NULL);
+ unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
+ unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
+ unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
+ unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
+ unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
+ unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
+ unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
+ unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
+ unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
+
+ tracepoint_synchronize_unregister();
+}
+
+/*
+ * struct blk_io_tracer formatting routines
+ */
+
+static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
+{
+ int i = 0;
+ int tc = t->action >> BLK_TC_SHIFT;
+
+ if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) {
+ rwbs[i++] = 'N';
+ goto out;
+ }
+
+ if (tc & BLK_TC_FLUSH)
+ rwbs[i++] = 'F';
+
+ if (tc & BLK_TC_DISCARD)
+ rwbs[i++] = 'D';
+ else if (tc & BLK_TC_WRITE)
+ rwbs[i++] = 'W';
+ else if (t->bytes)
+ rwbs[i++] = 'R';
+ else
+ rwbs[i++] = 'N';
+
+ if (tc & BLK_TC_FUA)
+ rwbs[i++] = 'F';
+ if (tc & BLK_TC_AHEAD)
+ rwbs[i++] = 'A';
+ if (tc & BLK_TC_SYNC)
+ rwbs[i++] = 'S';
+ if (tc & BLK_TC_META)
+ rwbs[i++] = 'M';
+out:
+ 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, bool has_cg)
+{
+ return (void *)(te_blk_io_trace(ent) + 1) +
+ (has_cg ? sizeof(union kernfs_node_id) : 0);
+}
+
+static inline const void *cgid_start(const struct trace_entry *ent)
+{
+ return (void *)(te_blk_io_trace(ent) + 1);
+}
+
+static inline int pdu_real_len(const struct trace_entry *ent, bool has_cg)
+{
+ return te_blk_io_trace(ent)->pdu_len -
+ (has_cg ? sizeof(union kernfs_node_id) : 0);
+}
+
+static inline u32 t_action(const struct trace_entry *ent)
+{
+ return te_blk_io_trace(ent)->action;
+}
+
+static inline u32 t_bytes(const struct trace_entry *ent)
+{
+ return te_blk_io_trace(ent)->bytes;
+}
+
+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)->error;
+}
+
+static __u64 get_pdu_int(const struct trace_entry *ent, bool has_cg)
+{
+ const __u64 *val = pdu_start(ent, has_cg);
+ return be64_to_cpu(*val);
+}
+
+static void get_pdu_remap(const struct trace_entry *ent,
+ struct blk_io_trace_remap *r, bool has_cg)
+{
+ const struct blk_io_trace_remap *__r = pdu_start(ent, has_cg);
+ __u64 sector_from = __r->sector_from;
+
+ r->device_from = be32_to_cpu(__r->device_from);
+ r->device_to = be32_to_cpu(__r->device_to);
+ r->sector_from = be64_to_cpu(sector_from);
+}
+
+typedef void (blk_log_action_t) (struct trace_iterator *iter, const char *act,
+ bool has_cg);
+
+static void blk_log_action_classic(struct trace_iterator *iter, const char *act,
+ bool has_cg)
+{
+ char rwbs[RWBS_LEN];
+ unsigned long long ts = iter->ts;
+ unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC);
+ unsigned secs = (unsigned long)ts;
+ const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
+
+ fill_rwbs(rwbs, t);
+
+ trace_seq_printf(&iter->seq,
+ "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
+ MAJOR(t->device), MINOR(t->device), iter->cpu,
+ secs, nsec_rem, iter->ent->pid, act, rwbs);
+}
+
+static void blk_log_action(struct trace_iterator *iter, const char *act,
+ bool has_cg)
+{
+ char rwbs[RWBS_LEN];
+ const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
+
+ fill_rwbs(rwbs, t);
+ if (has_cg) {
+ const union kernfs_node_id *id = cgid_start(iter->ent);
+
+ if (blk_tracer_flags.val & TRACE_BLK_OPT_CGNAME) {
+ char blkcg_name_buf[NAME_MAX + 1] = "<...>";
+
+ cgroup_path_from_kernfs_id(id, blkcg_name_buf,
+ sizeof(blkcg_name_buf));
+ trace_seq_printf(&iter->seq, "%3d,%-3d %s %2s %3s ",
+ MAJOR(t->device), MINOR(t->device),
+ blkcg_name_buf, act, rwbs);
+ } else
+ trace_seq_printf(&iter->seq,
+ "%3d,%-3d %x,%-x %2s %3s ",
+ MAJOR(t->device), MINOR(t->device),
+ id->ino, id->generation, act, rwbs);
+ } else
+ trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
+ MAJOR(t->device), MINOR(t->device), act, rwbs);
+}
+
+static void blk_log_dump_pdu(struct trace_seq *s,
+ const struct trace_entry *ent, bool has_cg)
+{
+ const unsigned char *pdu_buf;
+ int pdu_len;
+ int i, end;
+
+ pdu_buf = pdu_start(ent, has_cg);
+ pdu_len = pdu_real_len(ent, has_cg);
+
+ if (!pdu_len)
+ return;
+
+ /* find the last zero that needs to be printed */
+ for (end = pdu_len - 1; end >= 0; end--)
+ if (pdu_buf[end])
+ break;
+ end++;
+
+ trace_seq_putc(s, '(');
+
+ for (i = 0; i < pdu_len; i++) {
+
+ trace_seq_printf(s, "%s%02x",
+ i == 0 ? "" : " ", pdu_buf[i]);
+
+ /*
+ * stop when the rest is just zeroes and indicate so
+ * with a ".." appended
+ */
+ if (i == end && end != pdu_len - 1) {
+ trace_seq_puts(s, " ..) ");
+ return;
+ }
+ }
+
+ trace_seq_puts(s, ") ");
+}
+
+static void blk_log_generic(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
+{
+ char cmd[TASK_COMM_LEN];
+
+ trace_find_cmdline(ent->pid, cmd);
+
+ if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
+ trace_seq_printf(s, "%u ", t_bytes(ent));
+ blk_log_dump_pdu(s, ent, has_cg);
+ trace_seq_printf(s, "[%s]\n", cmd);
+ } else {
+ if (t_sec(ent))
+ trace_seq_printf(s, "%llu + %u [%s]\n",
+ t_sector(ent), t_sec(ent), cmd);
+ else
+ trace_seq_printf(s, "[%s]\n", cmd);
+ }
+}
+
+static void blk_log_with_error(struct trace_seq *s,
+ const struct trace_entry *ent, bool has_cg)
+{
+ if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
+ blk_log_dump_pdu(s, ent, has_cg);
+ trace_seq_printf(s, "[%d]\n", t_error(ent));
+ } else {
+ if (t_sec(ent))
+ trace_seq_printf(s, "%llu + %u [%d]\n",
+ t_sector(ent),
+ t_sec(ent), t_error(ent));
+ else
+ trace_seq_printf(s, "%llu [%d]\n",
+ t_sector(ent), t_error(ent));
+ }
+}
+
+static void blk_log_remap(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
+{
+ struct blk_io_trace_remap r = { .device_from = 0, };
+
+ get_pdu_remap(ent, &r, has_cg);
+ trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
+ t_sector(ent), t_sec(ent),
+ MAJOR(r.device_from), MINOR(r.device_from),
+ (unsigned long long)r.sector_from);
+}
+
+static void blk_log_plug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
+{
+ char cmd[TASK_COMM_LEN];
+
+ trace_find_cmdline(ent->pid, cmd);
+
+ trace_seq_printf(s, "[%s]\n", cmd);
+}
+
+static void blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
+{
+ char cmd[TASK_COMM_LEN];
+
+ trace_find_cmdline(ent->pid, cmd);
+
+ trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent, has_cg));
+}
+
+static void blk_log_split(struct trace_seq *s, const struct trace_entry *ent, bool has_cg)
+{
+ char cmd[TASK_COMM_LEN];
+
+ trace_find_cmdline(ent->pid, cmd);
+
+ trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
+ get_pdu_int(ent, has_cg), cmd);
+}
+
+static void blk_log_msg(struct trace_seq *s, const struct trace_entry *ent,
+ bool has_cg)
+{
+
+ trace_seq_putmem(s, pdu_start(ent, has_cg),
+ pdu_real_len(ent, has_cg));
+ trace_seq_putc(s, '\n');
+}
+
+/*
+ * 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)
+{
+ blk_tracer_enabled = true;
+}
+
+static int blk_tracer_init(struct trace_array *tr)
+{
+ blk_tr = tr;
+ blk_tracer_start(tr);
+ return 0;
+}
+
+static void blk_tracer_stop(struct trace_array *tr)
+{
+ blk_tracer_enabled = false;
+}
+
+static void blk_tracer_reset(struct trace_array *tr)
+{
+ blk_tracer_stop(tr);
+}
+
+static const struct {
+ const char *act[2];
+ void (*print)(struct trace_seq *s, const struct trace_entry *ent,
+ bool has_cg);
+} what2act[] = {
+ [__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 print_one_line(struct trace_iterator *iter,
+ bool classic)
+{
+ struct trace_array *tr = iter->tr;
+ struct trace_seq *s = &iter->seq;
+ const struct blk_io_trace *t;
+ u16 what;
+ bool long_act;
+ blk_log_action_t *log_action;
+ bool has_cg;
+
+ t = te_blk_io_trace(iter->ent);
+ what = (t->action & ((1 << BLK_TC_SHIFT) - 1)) & ~__BLK_TA_CGROUP;
+ long_act = !!(tr->trace_flags & TRACE_ITER_VERBOSE);
+ log_action = classic ? &blk_log_action_classic : &blk_log_action;
+ has_cg = t->action & __BLK_TA_CGROUP;
+
+ if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) {
+ log_action(iter, long_act ? "message" : "m", has_cg);
+ blk_log_msg(s, iter->ent, has_cg);
+ return trace_handle_return(s);
+ }
+
+ if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
+ trace_seq_printf(s, "Unknown action %x\n", what);
+ else {
+ log_action(iter, what2act[what].act[long_act], has_cg);
+ what2act[what].print(s, iter->ent, has_cg);
+ }
+
+ return trace_handle_return(s);
+}
+
+static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
+ int flags, struct trace_event *event)
+{
+ return print_one_line(iter, false);
+}
+
+static void 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 = iter->ts,
+ };
+
+ trace_seq_putmem(s, &old, offset);
+ 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,
+ struct trace_event *event)
+{
+ blk_trace_synthesize_old_trace(iter);
+
+ return trace_handle_return(&iter->seq);
+}
+
+static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
+{
+ if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
+ return TRACE_TYPE_UNHANDLED;
+
+ return print_one_line(iter, true);
+}
+
+static int
+blk_tracer_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
+{
+ /* don't output context-info for blk_classic output */
+ if (bit == TRACE_BLK_OPT_CLASSIC) {
+ if (set)
+ tr->trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
+ else
+ tr->trace_flags |= TRACE_ITER_CONTEXT_INFO;
+ }
+ return 0;
+}
+
+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,
+ .set_flag = blk_tracer_set_flag,
+};
+
+static struct trace_event_functions trace_blk_event_funcs = {
+ .trace = blk_trace_event_print,
+ .binary = blk_trace_event_print_binary,
+};
+
+static struct trace_event trace_blk_event = {
+ .type = TRACE_BLK,
+ .funcs = &trace_blk_event_funcs,
+};
+
+static int __init init_blk_tracer(void)
+{
+ if (!register_trace_event(&trace_blk_event)) {
+ pr_warn("Warning: could not register block events\n");
+ return 1;
+ }
+
+ if (register_tracer(&blk_tracer) != 0) {
+ pr_warn("Warning: could not register the block tracer\n");
+ unregister_trace_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;
+
+ put_probe_ref();
+ blk_trace_free(bt);
+ return 0;
+}
+
+/*
+ * Setup everything required to start tracing
+ */
+static int blk_trace_setup_queue(struct request_queue *q,
+ struct block_device *bdev)
+{
+ struct blk_trace *bt = NULL;
+ int ret = -ENOMEM;
+
+ bt = kzalloc(sizeof(*bt), GFP_KERNEL);
+ if (!bt)
+ return -ENOMEM;
+
+ bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
+ if (!bt->msg_data)
+ goto free_bt;
+
+ bt->dev = bdev->bd_dev;
+ bt->act_mask = (u16)-1;
+
+ blk_trace_setup_lba(bt, bdev);
+
+ ret = -EBUSY;
+ if (cmpxchg(&q->blk_trace, NULL, bt))
+ goto free_bt;
+
+ get_probe_ref();
+ return 0;
+
+free_bt:
+ blk_trace_free(bt);
+ return ret;
+}
+
+/*
+ * sysfs interface to enable and configure tracing
+ */
+
+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 BLK_TRACE_DEVICE_ATTR(enable);
+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 const struct {
+ int mask;
+ const char *str;
+} mask_maps[] = {
+ { BLK_TC_READ, "read" },
+ { BLK_TC_WRITE, "write" },
+ { BLK_TC_FLUSH, "flush" },
+ { BLK_TC_SYNC, "sync" },
+ { BLK_TC_QUEUE, "queue" },
+ { BLK_TC_REQUEUE, "requeue" },
+ { BLK_TC_ISSUE, "issue" },
+ { BLK_TC_COMPLETE, "complete" },
+ { BLK_TC_FS, "fs" },
+ { BLK_TC_PC, "pc" },
+ { BLK_TC_NOTIFY, "notify" },
+ { BLK_TC_AHEAD, "ahead" },
+ { BLK_TC_META, "meta" },
+ { BLK_TC_DISCARD, "discard" },
+ { BLK_TC_DRV_DATA, "drv_data" },
+ { BLK_TC_FUA, "fua" },
+};
+
+static int blk_trace_str2mask(const char *str)
+{
+ int i;
+ int mask = 0;
+ char *buf, *s, *token;
+
+ buf = kstrdup(str, GFP_KERNEL);
+ if (buf == NULL)
+ return -ENOMEM;
+ s = strstrip(buf);
+
+ while (1) {
+ token = strsep(&s, ",");
+ if (token == NULL)
+ break;
+
+ if (*token == '\0')
+ continue;
+
+ for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
+ if (strcasecmp(token, mask_maps[i].str) == 0) {
+ mask |= mask_maps[i].mask;
+ break;
+ }
+ }
+ if (i == ARRAY_SIZE(mask_maps)) {
+ mask = -EINVAL;
+ break;
+ }
+ }
+ kfree(buf);
+
+ return mask;
+}
+
+static ssize_t blk_trace_mask2str(char *buf, int mask)
+{
+ int i;
+ char *p = buf;
+
+ for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
+ if (mask & mask_maps[i].mask) {
+ p += sprintf(p, "%s%s",
+ (p == buf) ? "" : ",", mask_maps[i].str);
+ }
+ }
+ *p++ = '\n';
+
+ return p - buf;
+}
+
+static struct request_queue *blk_trace_get_queue(struct block_device *bdev)
+{
+ if (bdev->bd_disk == NULL)
+ return NULL;
+
+ return bdev_get_queue(bdev);
+}
+
+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;
+
+ bdev = bdget(part_devt(p));
+ if (bdev == NULL)
+ goto out;
+
+ q = blk_trace_get_queue(bdev);
+ if (q == NULL)
+ goto out_bdput;
+
+ mutex_lock(&q->blk_trace_mutex);
+
+ if (attr == &dev_attr_enable) {
+ ret = sprintf(buf, "%u\n", !!q->blk_trace);
+ goto out_unlock_bdev;
+ }
+
+ if (q->blk_trace == NULL)
+ ret = sprintf(buf, "disabled\n");
+ else if (attr == &dev_attr_act_mask)
+ ret = blk_trace_mask2str(buf, 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);
+
+out_unlock_bdev:
+ mutex_unlock(&q->blk_trace_mutex);
+out_bdput:
+ bdput(bdev);
+out:
+ 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 = -EINVAL;
+
+ if (count == 0)
+ goto out;
+
+ if (attr == &dev_attr_act_mask) {
+ if (kstrtoull(buf, 0, &value)) {
+ /* Assume it is a list of trace category names */
+ ret = blk_trace_str2mask(buf);
+ if (ret < 0)
+ goto out;
+ value = ret;
+ }
+ } else if (kstrtoull(buf, 0, &value))
+ goto out;
+
+ ret = -ENXIO;
+
+ p = dev_to_part(dev);
+ bdev = bdget(part_devt(p));
+ if (bdev == NULL)
+ goto out;
+
+ q = blk_trace_get_queue(bdev);
+ if (q == NULL)
+ goto out_bdput;
+
+ mutex_lock(&q->blk_trace_mutex);
+
+ if (attr == &dev_attr_enable) {
+ if (!!value == !!q->blk_trace) {
+ ret = 0;
+ goto out_unlock_bdev;
+ }
+ if (value)
+ ret = blk_trace_setup_queue(q, bdev);
+ else
+ ret = blk_trace_remove_queue(q);
+ goto out_unlock_bdev;
+ }
+
+ ret = 0;
+ if (q->blk_trace == NULL)
+ ret = blk_trace_setup_queue(q, bdev);
+
+ 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;
+ }
+
+out_unlock_bdev:
+ mutex_unlock(&q->blk_trace_mutex);
+out_bdput:
+ bdput(bdev);
+out:
+ return ret ? ret : count;
+}
+
+int blk_trace_init_sysfs(struct device *dev)
+{
+ return sysfs_create_group(&dev->kobj, &blk_trace_attr_group);
+}
+
+void blk_trace_remove_sysfs(struct device *dev)
+{
+ sysfs_remove_group(&dev->kobj, &blk_trace_attr_group);
+}
+
+#endif /* CONFIG_BLK_DEV_IO_TRACE */
+
+#ifdef CONFIG_EVENT_TRACING
+
+void blk_fill_rwbs(char *rwbs, unsigned int op, int bytes)
+{
+ int i = 0;
+
+ if (op & REQ_PREFLUSH)
+ rwbs[i++] = 'F';
+
+ switch (op & REQ_OP_MASK) {
+ case REQ_OP_WRITE:
+ case REQ_OP_WRITE_SAME:
+ rwbs[i++] = 'W';
+ break;
+ case REQ_OP_DISCARD:
+ rwbs[i++] = 'D';
+ break;
+ case REQ_OP_SECURE_ERASE:
+ rwbs[i++] = 'D';
+ rwbs[i++] = 'E';
+ break;
+ case REQ_OP_FLUSH:
+ rwbs[i++] = 'F';
+ break;
+ case REQ_OP_READ:
+ rwbs[i++] = 'R';
+ break;
+ default:
+ rwbs[i++] = 'N';
+ }
+
+ if (op & REQ_FUA)
+ rwbs[i++] = 'F';
+ if (op & REQ_RAHEAD)
+ rwbs[i++] = 'A';
+ if (op & REQ_SYNC)
+ rwbs[i++] = 'S';
+ if (op & REQ_META)
+ rwbs[i++] = 'M';
+
+ rwbs[i] = '\0';
+}
+EXPORT_SYMBOL_GPL(blk_fill_rwbs);
+
+#endif /* CONFIG_EVENT_TRACING */
+