]> nv-tegra.nvidia Code Review - linux-2.6.git/blobdiff - block/blktrace.c
ufs: Use lowercase names of quota functions
[linux-2.6.git] / block / blktrace.c
index 74e02c04b2dab6eb9567a49f9e589cfe69fb2e9e..7cf9d1ff45a015e0d8fe7be2546c6fb7f95f590e 100644 (file)
 #include <linux/mutex.h>
 #include <linux/debugfs.h>
 #include <linux/time.h>
+#include <trace/block.h>
 #include <asm/uaccess.h>
 
-static DEFINE_PER_CPU(unsigned long long, blk_trace_cpu_offset) = { 0, };
 static unsigned int blktrace_seq __read_mostly = 1;
 
+/* 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.
  */
@@ -41,7 +48,7 @@ static void trace_note(struct blk_trace *bt, pid_t pid, int action,
                const int cpu = smp_processor_id();
 
                t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
-               t->time = sched_clock() - per_cpu(blk_trace_cpu_offset, cpu);
+               t->time = ktime_to_ns(ktime_get());
                t->device = bt->dev;
                t->action = action;
                t->pid = pid;
@@ -76,6 +83,24 @@ static void trace_note_time(struct blk_trace *bt)
        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;
+
+       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)
 {
@@ -94,29 +119,15 @@ static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
  */
 static u32 ddir_act[2] __read_mostly = { BLK_TC_ACT(BLK_TC_READ), BLK_TC_ACT(BLK_TC_WRITE) };
 
-/*
- * Bio action bits of interest
- */
-static u32 bio_act[9] __read_mostly = { 0, BLK_TC_ACT(BLK_TC_BARRIER), BLK_TC_ACT(BLK_TC_SYNC), 0, BLK_TC_ACT(BLK_TC_AHEAD), 0, 0, 0, BLK_TC_ACT(BLK_TC_META) };
-
-/*
- * More could be added as needed, taking care to increment the decrementer
- * to get correct indexing
- */
-#define trace_barrier_bit(rw)  \
-       (((rw) & (1 << BIO_RW_BARRIER)) >> (BIO_RW_BARRIER - 0))
-#define trace_sync_bit(rw)     \
-       (((rw) & (1 << BIO_RW_SYNC)) >> (BIO_RW_SYNC - 1))
-#define trace_ahead_bit(rw)    \
-       (((rw) & (1 << BIO_RW_AHEAD)) << (2 - BIO_RW_AHEAD))
-#define trace_meta_bit(rw)     \
-       (((rw) & (1 << BIO_RW_META)) >> (BIO_RW_META - 3))
+/* 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.
  */
-void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
+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;
@@ -130,10 +141,11 @@ void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
                return;
 
        what |= ddir_act[rw & WRITE];
-       what |= bio_act[trace_barrier_bit(rw)];
-       what |= bio_act[trace_sync_bit(rw)];
-       what |= bio_act[trace_ahead_bit(rw)];
-       what |= bio_act[trace_meta_bit(rw)];
+       what |= MASK_TC_BIT(rw, BARRIER);
+       what |= MASK_TC_BIT(rw, SYNCIO);
+       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)))
@@ -142,10 +154,7 @@ void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
        /*
         * 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. Once reserved, it's
-        * enough to get preemption disabled to prevent read of this data
-        * before we are through filling it. get_cpu()/put_cpu() does this
-        * for us
+        * from coming in and stepping on our toes.
         */
        local_irq_save(flags);
 
@@ -159,7 +168,7 @@ void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
 
                t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
                t->sequence = ++(*sequence);
-               t->time = sched_clock() - per_cpu(blk_trace_cpu_offset, cpu);
+               t->time = ktime_to_ns(ktime_get());
                t->sector = sector;
                t->bytes = bytes;
                t->action = what;
@@ -176,62 +185,24 @@ void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
        local_irq_restore(flags);
 }
 
-EXPORT_SYMBOL_GPL(__blk_add_trace);
-
 static struct dentry *blk_tree_root;
-static struct mutex blk_tree_mutex;
-static unsigned int root_users;
-
-static inline void blk_remove_root(void)
-{
-       if (blk_tree_root) {
-               debugfs_remove(blk_tree_root);
-               blk_tree_root = NULL;
-       }
-}
-
-static void blk_remove_tree(struct dentry *dir)
-{
-       mutex_lock(&blk_tree_mutex);
-       debugfs_remove(dir);
-       if (--root_users == 0)
-               blk_remove_root();
-       mutex_unlock(&blk_tree_mutex);
-}
-
-static struct dentry *blk_create_tree(const char *blk_name)
-{
-       struct dentry *dir = NULL;
-
-       mutex_lock(&blk_tree_mutex);
-
-       if (!blk_tree_root) {
-               blk_tree_root = debugfs_create_dir("block", NULL);
-               if (!blk_tree_root)
-                       goto err;
-       }
-
-       dir = debugfs_create_dir(blk_name, blk_tree_root);
-       if (dir)
-               root_users++;
-       else
-               blk_remove_root();
-
-err:
-       mutex_unlock(&blk_tree_mutex);
-       return dir;
-}
+static DEFINE_MUTEX(blk_tree_mutex);
 
 static void blk_trace_cleanup(struct blk_trace *bt)
 {
-       relay_close(bt->rchan);
+       debugfs_remove(bt->msg_file);
        debugfs_remove(bt->dropped_file);
-       blk_remove_tree(bt->dir);
+       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);
 }
 
-static int blk_trace_remove(request_queue_t *q)
+int blk_trace_remove(struct request_queue *q)
 {
        struct blk_trace *bt;
 
@@ -245,6 +216,7 @@ static int blk_trace_remove(request_queue_t *q)
 
        return 0;
 }
+EXPORT_SYMBOL_GPL(blk_trace_remove);
 
 static int blk_dropped_open(struct inode *inode, struct file *filp)
 {
@@ -264,12 +236,50 @@ static ssize_t blk_dropped_read(struct file *filp, char __user *buffer,
        return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf));
 }
 
-static struct file_operations blk_dropped_fops = {
+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.
@@ -289,7 +299,18 @@ static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
 
 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;
 }
 
@@ -312,33 +333,26 @@ static struct rchan_callbacks blk_relay_callbacks = {
 /*
  * Setup everything required to start tracing
  */
-static int blk_trace_setup(request_queue_t *q, struct block_device *bdev,
-                          char __user *arg)
+int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
+                       struct blk_user_trace_setup *buts)
 {
-       struct blk_user_trace_setup buts;
        struct blk_trace *old_bt, *bt = NULL;
        struct dentry *dir = NULL;
-       char b[BDEVNAME_SIZE];
        int ret, i;
 
-       if (copy_from_user(&buts, arg, sizeof(buts)))
-               return -EFAULT;
-
-       if (!buts.buf_size || !buts.buf_nr)
+       if (!buts->buf_size || !buts->buf_nr)
                return -EINVAL;
 
-       strcpy(buts.name, bdevname(bdev, b));
+       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] = '_';
-
-       if (copy_to_user(arg, &buts, sizeof(buts)))
-               return -EFAULT;
+       for (i = 0; i < strlen(buts->name); i++)
+               if (buts->name[i] == '/')
+                       buts->name[i] = '_';
 
        ret = -ENOMEM;
        bt = kzalloc(sizeof(*bt), GFP_KERNEL);
@@ -349,13 +363,25 @@ static int blk_trace_setup(request_queue_t *q, struct block_device *bdev,
        if (!bt->sequence)
                goto err;
 
+       bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG);
+       if (!bt->msg_data)
+               goto err;
+
        ret = -ENOENT;
-       dir = blk_create_tree(buts.name);
+
+       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 = bdev->bd_dev;
+       bt->dev = dev;
        atomic_set(&bt->dropped, 0);
 
        ret = -EIO;
@@ -363,23 +389,35 @@ static int blk_trace_setup(request_queue_t *q, struct block_device *bdev,
        if (!bt->dropped_file)
                goto err;
 
-       bt->rchan = relay_open("trace", dir, buts.buf_size, buts.buf_nr, &blk_relay_callbacks);
+       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->rchan->private_data = bt;
 
-       bt->act_mask = buts.act_mask;
+       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;
+       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->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) {
@@ -388,14 +426,17 @@ static int blk_trace_setup(request_queue_t *q, struct block_device *bdev,
        }
 
        return 0;
+probe_err:
+       atomic_dec(&blk_probes_ref);
+       mutex_unlock(&blk_probe_mutex);
 err:
-       if (dir)
-               blk_remove_tree(dir);
        if (bt) {
+               if (bt->msg_file)
+                       debugfs_remove(bt->msg_file);
                if (bt->dropped_file)
                        debugfs_remove(bt->dropped_file);
-               if (bt->sequence)
-                       free_percpu(bt->sequence);
+               free_percpu(bt->sequence);
+               free_percpu(bt->msg_data);
                if (bt->rchan)
                        relay_close(bt->rchan);
                kfree(bt);
@@ -403,7 +444,28 @@ err:
        return ret;
 }
 
-static int blk_trace_startstop(request_queue_t *q, int start)
+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)
 {
        struct blk_trace *bt;
        int ret;
@@ -436,6 +498,7 @@ static int blk_trace_startstop(request_queue_t *q, int start)
 
        return ret;
 }
+EXPORT_SYMBOL_GPL(blk_trace_startstop);
 
 /**
  * blk_trace_ioctl: - handle the ioctls associated with tracing
@@ -446,8 +509,9 @@ static int blk_trace_startstop(request_queue_t *q, int start)
  **/
 int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
 {
-       request_queue_t *q;
+       struct request_queue *q;
        int ret, start = 0;
+       char b[BDEVNAME_SIZE];
 
        q = bdev_get_queue(bdev);
        if (!q)
@@ -457,7 +521,8 @@ int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
 
        switch (cmd) {
        case BLKTRACESETUP:
-               ret = blk_trace_setup(q, bdev, arg);
+               bdevname(bdev, b);
+               ret = blk_trace_setup(q, b, bdev->bd_dev, arg);
                break;
        case BLKTRACESTART:
                start = 1;
@@ -481,7 +546,7 @@ int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
  * @q:    the request queue associated with the device
  *
  **/
-void blk_trace_shutdown(request_queue_t *q)
+void blk_trace_shutdown(struct request_queue *q)
 {
        if (q->blk_trace) {
                blk_trace_startstop(q, 0);
@@ -490,75 +555,306 @@ void blk_trace_shutdown(request_queue_t *q)
 }
 
 /*
- * Average offset over two calls to sched_clock() with a gettimeofday()
- * in the middle
+ * blktrace probes
  */
-static void blk_check_time(unsigned long long *t)
+
+/**
+ * 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)
 {
-       unsigned long long a, b;
-       struct timeval tv;
+       struct blk_trace *bt = q->blk_trace;
+       int rw = rq->cmd_flags & 0x03;
 
-       a = sched_clock();
-       do_gettimeofday(&tv);
-       b = sched_clock();
+       if (likely(!bt))
+               return;
 
-       *t = tv.tv_sec * 1000000000 + tv.tv_usec * 1000;
-       *t -= (a + b) / 2;
+       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);
+       }
 }
 
-/*
- * calibrate our inter-CPU timings
- */
-static void blk_trace_check_cpu_time(void *data)
+static void blk_add_trace_rq_abort(struct request_queue *q, struct request *rq)
 {
-       unsigned long long *t;
-       int cpu = get_cpu();
+       blk_add_trace_rq(q, rq, BLK_TA_ABORT);
+}
 
-       t = &per_cpu(blk_trace_cpu_offset, cpu);
+static void blk_add_trace_rq_insert(struct request_queue *q, struct request *rq)
+{
+       blk_add_trace_rq(q, rq, BLK_TA_INSERT);
+}
 
-       /*
-        * Just call it twice, hopefully the second call will be cache hot
-        * and a little more precise
-        */
-       blk_check_time(t);
-       blk_check_time(t);
+static void blk_add_trace_rq_issue(struct request_queue *q, struct request *rq)
+{
+       blk_add_trace_rq(q, rq, BLK_TA_ISSUE);
+}
 
-       put_cpu();
+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_trace_set_ht_offsets(void)
+static void blk_add_trace_rq_complete(struct request_queue *q, struct request *rq)
 {
-#if defined(CONFIG_SCHED_SMT)
-       int cpu, i;
+       blk_add_trace_rq(q, rq, BLK_TA_COMPLETE);
+}
 
-       /*
-        * now make sure HT siblings have the same time offset
-        */
-       preempt_disable();
-       for_each_online_cpu(cpu) {
-               unsigned long long *cpu_off, *sibling_off;
+/**
+ * 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;
 
-               for_each_cpu_mask(i, cpu_sibling_map[cpu]) {
-                       if (i == cpu)
-                               continue;
+       if (likely(!bt))
+               return;
 
-                       cpu_off = &per_cpu(blk_trace_cpu_offset, cpu);
-                       sibling_off = &per_cpu(blk_trace_cpu_offset, i);
-                       *sibling_off = *cpu_off;
-               }
+       __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);
        }
-       preempt_enable();
-#endif
 }
 
-static __init int blk_trace_init(void)
+static void blk_add_trace_plug(struct request_queue *q)
 {
-       mutex_init(&blk_tree_mutex);
-       on_each_cpu(blk_trace_check_cpu_time, NULL, 1, 1);
-       blk_trace_set_ht_offsets();
+       struct blk_trace *bt = q->blk_trace;
 
-       return 0;
+       if (bt)
+               __blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL);
 }
 
-module_init(blk_trace_init);
+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();
+}