unsigned long long last_reported_time;
unsigned long long last_read_time;
struct io_stats io_stats;
- unsigned long last_sequence;
unsigned long skips, nskips;
unsigned long long seq_skips, seq_nskips;
unsigned int max_depth[2];
unsigned int cur_depth[2];
- struct rb_root rb_last;
- unsigned long rb_last_entries;
-
struct rb_root rb_track;
int nfiles;
static int ndevices;
static struct per_dev_info *devices;
static char *get_dev_name(struct per_dev_info *, char *, int);
+static int trace_rb_insert_last(struct per_dev_info *, struct trace *);
FILE *ofp = NULL;
static char *output_name;
static unsigned long long genesis_time;
static unsigned long long last_allowed_time;
-static unsigned int smallest_seq_read;
static unsigned long long stopwatch_start; /* start from zero by default */
static unsigned long long stopwatch_end = -1ULL; /* "infinity" */
#define CPU_IDX(cpu) ((cpu) / CPUS_PER_LONG)
#define CPU_BIT(cpu) ((cpu) & (CPUS_PER_LONG - 1))
+static void resize_cpu_info(struct per_dev_info *pdi, int cpu)
+{
+ struct per_cpu_info *cpus = pdi->cpus;
+ int ncpus = pdi->ncpus;
+ int new_count = cpu + 1;
+ int new_space, size;
+ char *new_start;
+
+ size = new_count * sizeof(struct per_cpu_info);
+ cpus = realloc(cpus, size);
+ if (!cpus) {
+ char name[20];
+ fprintf(stderr, "Out of memory, CPU info for device %s (%d)\n",
+ get_dev_name(pdi, name, sizeof(name)), size);
+ exit(1);
+ }
+
+ new_start = (char *)cpus + (ncpus * sizeof(struct per_cpu_info));
+ new_space = (new_count - ncpus) * sizeof(struct per_cpu_info);
+ memset(new_start, 0, new_space);
+
+ pdi->ncpus = new_count;
+ pdi->cpus = cpus;
+
+ for (new_count = 0; new_count < pdi->ncpus; new_count++) {
+ struct per_cpu_info *pci = &pdi->cpus[new_count];
+
+ if (!pci->fd) {
+ pci->fd = -1;
+ memset(&pci->rb_last, 0, sizeof(pci->rb_last));
+ pci->rb_last_entries = 0;
+ pci->last_sequence = -1;
+ }
+ }
+}
+
+static struct per_cpu_info *get_cpu_info(struct per_dev_info *pdi, int cpu)
+{
+ struct per_cpu_info *pci;
+
+ if (cpu >= pdi->ncpus)
+ resize_cpu_info(pdi, cpu);
+
+ pci = &pdi->cpus[cpu];
+ pci->cpu = cpu;
+ return pci;
+}
+
+
+static int resize_devices(char *name)
+{
+ int size = (ndevices + 1) * sizeof(struct per_dev_info);
+
+ devices = realloc(devices, size);
+ if (!devices) {
+ fprintf(stderr, "Out of memory, device %s (%d)\n", name, size);
+ return 1;
+ }
+ memset(&devices[ndevices], 0, sizeof(struct per_dev_info));
+ devices[ndevices].name = name;
+ ndevices++;
+ return 0;
+}
+
+static struct per_dev_info *get_dev_info(dev_t dev)
+{
+ struct per_dev_info *pdi;
+ int i;
+
+ for (i = 0; i < ndevices; i++) {
+ if (!devices[i].dev)
+ devices[i].dev = dev;
+ if (devices[i].dev == dev)
+ return &devices[i];
+ }
+
+ if (resize_devices(NULL))
+ return NULL;
+
+ pdi = &devices[ndevices - 1];
+ pdi->dev = dev;
+ pdi->first_reported_time = 0;
+ pdi->last_read_time = 0;
+ pdi->skips_head = pdi->skips_tail = NULL;
+
+ return pdi;
+}
+
static void insert_skip(struct per_dev_info *pdi, unsigned long start,
unsigned long end)
{
return ppi;
}
+/*
+ * struct trace and blktrace allocation cache, we do potentially
+ * millions of mallocs for these structures while only using at most
+ * a few thousand at the time
+ */
+static inline void t_free(struct trace *t)
+{
+ if (t_alloc_cache < 1024) {
+ t->next = t_alloc_list;
+ t_alloc_list = t;
+ t_alloc_cache++;
+ } else
+ free(t);
+}
+
+static inline struct trace *t_alloc(void)
+{
+ struct trace *t = t_alloc_list;
+
+ if (t) {
+ t_alloc_list = t->next;
+ t_alloc_cache--;
+ return t;
+ }
+
+ return malloc(sizeof(*t));
+}
+
+static inline void bit_free(struct blk_io_trace *bit)
+{
+ if (bit_alloc_cache < 1024 && !bit->pdu_len) {
+ /*
+ * abuse a 64-bit field for a next pointer for the free item
+ */
+ bit->time = (__u64) (unsigned long) bit_alloc_list;
+ bit_alloc_list = (struct blk_io_trace *) bit;
+ bit_alloc_cache++;
+ } else
+ free(bit);
+}
+
+static inline struct blk_io_trace *bit_alloc(void)
+{
+ struct blk_io_trace *bit = bit_alloc_list;
+
+ if (bit) {
+ bit_alloc_list = (struct blk_io_trace *) (unsigned long) \
+ bit->time;
+ bit_alloc_cache--;
+ return bit;
+ }
+
+ return malloc(sizeof(*bit));
+}
+
+static inline void __put_trace_last(struct per_dev_info *pdi, struct trace *t)
+{
+ struct per_cpu_info *pci = get_cpu_info(pdi, t->bit->cpu);
+
+ rb_erase(&t->rb_node, &pci->rb_last);
+ pci->rb_last_entries--;
+
+ bit_free(t->bit);
+ t_free(t);
+}
+
+static void put_trace(struct per_dev_info *pdi, struct trace *t)
+{
+ rb_erase(&t->rb_node, &rb_sort_root);
+ rb_sort_entries--;
+
+ trace_rb_insert_last(pdi, t);
+}
+
static inline int trace_rb_insert(struct trace *t, struct rb_root *root)
{
struct rb_node **p = &root->rb_node;
return 1;
}
-static inline int trace_rb_insert_last(struct per_dev_info *pdi,struct trace *t)
+static int trace_rb_insert_last(struct per_dev_info *pdi, struct trace *t)
{
- if (!trace_rb_insert(t, &pdi->rb_last)) {
- pdi->rb_last_entries++;
- return 0;
+ struct per_cpu_info *pci = get_cpu_info(pdi, t->bit->cpu);
+
+ if (trace_rb_insert(t, &pci->rb_last))
+ return 1;
+
+ pci->rb_last_entries++;
+
+ if (pci->rb_last_entries > rb_batch * pdi->nfiles) {
+ struct rb_node *n = rb_first(&pci->rb_last);
+
+ t = rb_entry(n, struct trace, rb_node);
+ __put_trace_last(pdi, t);
}
- return 1;
+ return 0;
}
static struct trace *trace_rb_find(dev_t device, unsigned long sequence,
return NULL;
}
-static inline struct trace *trace_rb_find_sort(dev_t dev, unsigned long seq)
-{
- return trace_rb_find(dev, seq, &rb_sort_root, 1);
-}
-
static inline struct trace *trace_rb_find_last(struct per_dev_info *pdi,
+ struct per_cpu_info *pci,
unsigned long seq)
{
- return trace_rb_find(pdi->dev, seq, &pdi->rb_last, 0);
+ return trace_rb_find(pdi->dev, seq, &pci->rb_last, 0);
}
static inline int track_rb_insert(struct per_dev_info *pdi,struct io_track *iot)
return &ppi->io_stats;
}
-static void resize_cpu_info(struct per_dev_info *pdi, int cpu)
-{
- struct per_cpu_info *cpus = pdi->cpus;
- int ncpus = pdi->ncpus;
- int new_count = cpu + 1;
- int new_space, size;
- char *new_start;
-
- size = new_count * sizeof(struct per_cpu_info);
- cpus = realloc(cpus, size);
- if (!cpus) {
- char name[20];
- fprintf(stderr, "Out of memory, CPU info for device %s (%d)\n",
- get_dev_name(pdi, name, sizeof(name)), size);
- exit(1);
- }
-
- new_start = (char *)cpus + (ncpus * sizeof(struct per_cpu_info));
- new_space = (new_count - ncpus) * sizeof(struct per_cpu_info);
- memset(new_start, 0, new_space);
-
- pdi->ncpus = new_count;
- pdi->cpus = cpus;
-
- for (new_count = 0; new_count < pdi->ncpus; new_count++)
- if (!pdi->cpus[new_count].fd)
- pdi->cpus[new_count].fd = -1;
-}
-
-static struct per_cpu_info *get_cpu_info(struct per_dev_info *pdi, int cpu)
-{
- struct per_cpu_info *pci;
-
- if (cpu >= pdi->ncpus)
- resize_cpu_info(pdi, cpu);
-
- pci = &pdi->cpus[cpu];
- pci->cpu = cpu;
- return pci;
-}
-
-
-static int resize_devices(char *name)
-{
- int size = (ndevices + 1) * sizeof(struct per_dev_info);
-
- devices = realloc(devices, size);
- if (!devices) {
- fprintf(stderr, "Out of memory, device %s (%d)\n", name, size);
- return 1;
- }
- memset(&devices[ndevices], 0, sizeof(struct per_dev_info));
- devices[ndevices].name = name;
- ndevices++;
- return 0;
-}
-
-static struct per_dev_info *get_dev_info(dev_t dev)
-{
- struct per_dev_info *pdi;
- int i;
-
- for (i = 0; i < ndevices; i++) {
- if (!devices[i].dev)
- devices[i].dev = dev;
- if (devices[i].dev == dev)
- return &devices[i];
- }
-
- if (resize_devices(NULL))
- return NULL;
-
- pdi = &devices[ndevices - 1];
- pdi->dev = dev;
- pdi->first_reported_time = 0;
- pdi->last_sequence = -1;
- pdi->last_read_time = 0;
- memset(&pdi->rb_last, 0, sizeof(pdi->rb_last));
- pdi->rb_last_entries = 0;
-
- pdi->skips_head = pdi->skips_tail = NULL;
-
- return pdi;
-}
-
static char *get_dev_name(struct per_dev_info *pdi, char *buffer, int size)
{
if (pdi->name)
}
}
-/*
- * struct trace and blktrace allocation cache, we do potentially
- * millions of mallocs for these structures while only using at most
- * a few thousand at the time
- */
-static inline void t_free(struct trace *t)
-{
- if (t_alloc_cache < 1024) {
- t->next = t_alloc_list;
- t_alloc_list = t;
- t_alloc_cache++;
- } else
- free(t);
-}
-
-static inline struct trace *t_alloc(void)
-{
- struct trace *t = t_alloc_list;
-
- if (t) {
- t_alloc_list = t->next;
- t_alloc_cache--;
- return t;
- }
-
- return malloc(sizeof(*t));
-}
-
-static inline void bit_free(struct blk_io_trace *bit)
-{
- if (bit_alloc_cache < 1024 && !bit->pdu_len) {
- /*
- * abuse a 64-bit field for a next pointer for the free item
- */
- bit->time = (__u64) (unsigned long) bit_alloc_list;
- bit_alloc_list = (struct blk_io_trace *) bit;
- bit_alloc_cache++;
- } else
- free(bit);
-}
-
-static inline struct blk_io_trace *bit_alloc(void)
-{
- struct blk_io_trace *bit = bit_alloc_list;
-
- if (bit) {
- bit_alloc_list = (struct blk_io_trace *) (unsigned long) \
- bit->time;
- bit_alloc_cache--;
- return bit;
- }
-
- return malloc(sizeof(*bit));
-}
-
static void find_genesis(void)
{
struct trace *t = trace_list;
*/
static int sort_entries(unsigned long long *youngest)
{
+ struct per_dev_info *pdi = NULL;
+ struct per_cpu_info *pci = NULL;
struct trace *t;
if (!genesis_time)
if (bit->time < *youngest || !*youngest)
*youngest = bit->time;
- if (bit->sequence < smallest_seq_read)
- smallest_seq_read = bit->sequence;
+ if (!pdi || pdi->dev != bit->device) {
+ pdi = get_dev_info(bit->device);
+ pci = NULL;
+ }
+
+ if (!pci || pci->cpu != bit->cpu)
+ pci = get_cpu_info(pdi, bit->cpu);
+
+ if (bit->sequence < pci->smallest_seq_read)
+ pci->smallest_seq_read = bit->sequence;
if (check_stopwatch(bit)) {
bit_free(bit);
return 0;
}
-static inline void __put_trace_last(struct per_dev_info *pdi, struct trace *t)
-{
- rb_erase(&t->rb_node, &pdi->rb_last);
- pdi->rb_last_entries--;
-
- bit_free(t->bit);
- t_free(t);
-}
-
-static void put_trace(struct per_dev_info *pdi, struct trace *t)
-{
- rb_erase(&t->rb_node, &rb_sort_root);
- rb_sort_entries--;
-
- trace_rb_insert_last(pdi, t);
-
- if (pdi->rb_last_entries > rb_batch * pdi->nfiles) {
- struct rb_node *n = rb_first(&pdi->rb_last);
-
- t = rb_entry(n, struct trace, rb_node);
- __put_trace_last(pdi, t);
- }
-}
-
/*
* to continue, we must have traces from all online cpus in the tree
*/
static int check_sequence(struct per_dev_info *pdi, struct trace *t, int force)
{
- unsigned long expected_sequence = pdi->last_sequence + 1;
struct blk_io_trace *bit = t->bit;
+ unsigned long expected_sequence;
+ struct per_cpu_info *pci;
struct trace *__t;
+ pci = get_cpu_info(pdi, bit->cpu);
+ expected_sequence = pci->last_sequence + 1;
+
if (!expected_sequence) {
/*
* 1 should be the first entry, just allow it
*/
if (bit->sequence == 1)
return 0;
- if (bit->sequence == smallest_seq_read)
+ if (bit->sequence == pci->smallest_seq_read)
return 0;
return check_cpu_map(pdi);
* we may not have seen that sequence yet. if we are not doing
* the final run, break and wait for more entries.
*/
- if (expected_sequence < smallest_seq_read) {
- __t = trace_rb_find_last(pdi, expected_sequence);
+ if (expected_sequence < pci->smallest_seq_read) {
+ __t = trace_rb_find_last(pdi, pci, expected_sequence);
if (!__t)
goto skip;
t = rb_entry(n, struct trace, rb_node);
bit = t->bit;
- if (!pdi || pdi->dev != bit->device)
+ if (!pdi || pdi->dev != bit->device) {
pdi = get_dev_info(bit->device);
+ pci = NULL;
+ }
if (!pdi) {
fprintf(stderr, "Unknown device ID? (%d,%d)\n",
if (!force && bit->time > last_allowed_time)
break;
- pdi->last_sequence = bit->sequence;
-
check_time(pdi, bit);
if (!pci || pci->cpu != bit->cpu)
pci = get_cpu_info(pdi, bit->cpu);
+ pci->last_sequence = bit->sequence;
+
pci->nelems++;
if (bit->action & (act_mask << BLK_TC_SHIFT))
for (i = 0; i < ndevices; i++) {
pdi = &devices[i];
pdi->nfiles = 0;
- pdi->last_sequence = -1;
for (j = 0;; j++) {
struct stat st;
events_added = 0;
last_allowed_time = -1ULL;
- smallest_seq_read = -1U;
for (i = 0; i < ndevices; i++) {
pdi = &devices[i];
if (pci->fd == -1)
continue;
+ pci->smallest_seq_read = -1;
+
events = read_events(pci->fd, 1, &pci->fdblock);
if (events <= 0) {
cpu_mark_offline(pdi, pci->cpu);
fdblock = -1;
while ((events = read_events(fd, 0, &fdblock)) > 0) {
+#if 0
smallest_seq_read = -1U;
+#endif
if (sort_entries(&youngest))
break;
#include <endian.h>
#include "blktrace_api.h"
+#include "rbtree.h"
#define MINORBITS 20
#define MINORMASK ((1U << MINORBITS) - 1)
char fname[128];
struct io_stats io_stats;
+
+ struct rb_root rb_last;
+ unsigned long rb_last_entries;
+ unsigned long last_sequence;
+ unsigned long smallest_seq_read;
};
extern FILE *ofp;
#define CHECK_MAGIC(t) (((t)->magic & 0xffffff00) == BLK_IO_TRACE_MAGIC)
-#define SUPPORTED_VERSION (0x05)
+#define SUPPORTED_VERSION (0x06)
#if __BYTE_ORDER == __LITTLE_ENDIAN
#define be16_to_cpu(x) __bswap_16(x)
#define BLK_TA_REMAP (__BLK_TA_REMAP | BLK_TC_ACT(BLK_TC_QUEUE))
#define BLK_IO_TRACE_MAGIC 0x65617400
-#define BLK_IO_TRACE_VERSION 0x05
+#define BLK_IO_TRACE_VERSION 0x06
/*
* The trace itself
+++ /dev/null
-diff --git a/block/Kconfig b/block/Kconfig
-index 377f6dd..27eaed9 100644
---- a/block/Kconfig
-+++ b/block/Kconfig
-@@ -11,4 +11,15 @@ config LBD
- your machine, or if you want to have a raid or loopback device
- bigger than 2TB. Otherwise say N.
-
-+config BLK_DEV_IO_TRACE
-+ bool "Support for tracing block io actions"
-+ select RELAYFS_FS
-+ 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 user space
-+ support tools needed), fetch the blktrace app from:
-+
-+ git://brick.kernel.dk/data/git/blktrace.git
-+
- source block/Kconfig.iosched
-diff --git a/block/Makefile b/block/Makefile
-index 7e4f93e..c05de0e 100644
---- a/block/Makefile
-+++ b/block/Makefile
-@@ -8,3 +8,5 @@ obj-$(CONFIG_IOSCHED_NOOP) += noop-iosch
- obj-$(CONFIG_IOSCHED_AS) += as-iosched.o
- obj-$(CONFIG_IOSCHED_DEADLINE) += deadline-iosched.o
- obj-$(CONFIG_IOSCHED_CFQ) += cfq-iosched.o
-+
-+obj-$(CONFIG_BLK_DEV_IO_TRACE) += blktrace.o
-diff --git a/block/blktrace.c b/block/blktrace.c
-new file mode 100644
-index 0000000..d12d166
---- /dev/null
-+++ b/block/blktrace.c
-@@ -0,0 +1,360 @@
-+#include <linux/config.h>
-+#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 <asm/uaccess.h>
-+
-+static DEFINE_PER_CPU(unsigned long long, blk_trace_cpu_offset) = { 0, };
-+
-+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 blk_io_trace t;
-+ unsigned long flags;
-+ void *rbuf;
-+ pid_t pid;
-+ int cpu;
-+
-+ if (rw & (1 << BIO_RW_BARRIER))
-+ what |= BLK_TC_ACT(BLK_TC_BARRIER);
-+ if (rw & (1 << BIO_RW_SYNC))
-+ what |= BLK_TC_ACT(BLK_TC_SYNC);
-+
-+ if (rw & WRITE)
-+ what |= BLK_TC_ACT(BLK_TC_WRITE);
-+ else
-+ what |= BLK_TC_ACT(BLK_TC_READ);
-+
-+ if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0)
-+ return;
-+ if (sector < bt->start_lba || sector > bt->end_lba)
-+ return;
-+
-+ pid = current->pid;
-+ if (bt->pid && pid != bt->pid)
-+ return;
-+
-+ t.magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
-+
-+ t.device = bt->dev;
-+ t.sector = sector;
-+ t.bytes = bytes;
-+ t.action = what;
-+ t.error = error;
-+ t.pdu_len = pdu_len;
-+
-+ t.pid = pid;
-+ memcpy(t.comm, current->comm, sizeof(t.comm));
-+
-+ /*
-+ * need to serialize this part completely to prevent multiple CPUs
-+ * from misordering events
-+ */
-+ spin_lock_irqsave(&bt->lock, flags);
-+
-+ t.sequence = ++bt->sequence;
-+
-+ cpu = smp_processor_id();
-+ t.cpu = cpu;
-+ t.time = sched_clock() - per_cpu(blk_trace_cpu_offset, cpu);
-+
-+ rbuf = relay_reserve(bt->rchan, sizeof(t) + pdu_len);
-+ if (rbuf) {
-+ memcpy(rbuf, &t, sizeof(t));
-+ if (pdu_len)
-+ memcpy(rbuf + sizeof(t), pdu_data, pdu_len);
-+ }
-+
-+ spin_unlock_irqrestore(&bt->lock, flags);
-+}
-+
-+EXPORT_SYMBOL_GPL(__blk_add_trace);
-+
-+static struct dentry *blk_tree_root;
-+static struct mutex blk_tree_mutex;
-+
-+static inline void blk_remove_root(void)
-+{
-+ if (relayfs_remove_dir(blk_tree_root) != -ENOTEMPTY)
-+ blk_tree_root = NULL;
-+}
-+
-+static void blk_remove_tree(struct dentry *dir)
-+{
-+ mutex_lock(&blk_tree_mutex);
-+ relayfs_remove_dir(dir);
-+ 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 = relayfs_create_dir("block", NULL);
-+ if (!blk_tree_root)
-+ goto err;
-+ }
-+
-+ dir = relayfs_create_dir(blk_name, blk_tree_root);
-+ if (!dir)
-+ blk_remove_root();
-+
-+err:
-+ mutex_unlock(&blk_tree_mutex);
-+ return dir;
-+}
-+
-+void blk_cleanup_trace(struct blk_trace *bt)
-+{
-+ relay_close(bt->rchan);
-+ relayfs_remove_file(bt->dropped_file);
-+ blk_remove_tree(bt->dir);
-+ kfree(bt);
-+}
-+
-+int blk_stop_trace(struct block_device *bdev)
-+{
-+ request_queue_t *q = bdev_get_queue(bdev);
-+ struct blk_trace *bt = NULL;
-+ int ret = -EINVAL;
-+
-+ if (!q)
-+ return -ENXIO;
-+
-+ down(&bdev->bd_sem);
-+
-+ if (q->blk_trace) {
-+ bt = q->blk_trace;
-+ q->blk_trace = NULL;
-+ ret = 0;
-+ }
-+
-+ up(&bdev->bd_sem);
-+
-+ if (bt)
-+ blk_cleanup_trace(bt);
-+
-+ return ret;
-+}
-+
-+static int blk_dropped_open(struct inode *inode, struct file *filp)
-+{
-+ filp->private_data = inode->u.generic_ip;
-+
-+ 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 struct file_operations blk_dropped_fops = {
-+ .owner = THIS_MODULE,
-+ .open = blk_dropped_open,
-+ .read = blk_dropped_read,
-+};
-+
-+static int blk_subbuf_start_callback (struct rchan_buf *buf,
-+ void *subbuf,
-+ void *prev_subbuf,
-+ size_t prev_padding)
-+{
-+ if (relay_buf_full(buf)) {
-+ struct blk_trace *bt = buf->chan->private_data;
-+
-+ atomic_inc(&bt->dropped);
-+ return 0;
-+ }
-+
-+ return 1;
-+}
-+
-+static struct rchan_callbacks blk_relay_callbacks = {
-+ .subbuf_start = blk_subbuf_start_callback,
-+};
-+
-+int blk_start_trace(struct block_device *bdev, char __user *arg)
-+{
-+ request_queue_t *q = bdev_get_queue(bdev);
-+ struct blk_user_trace_setup buts;
-+ struct blk_trace *bt = NULL;
-+ struct dentry *dir = NULL;
-+ char b[BDEVNAME_SIZE];
-+ int ret, i;
-+
-+ if (!q)
-+ return -ENXIO;
-+
-+ if (copy_from_user(&buts, arg, sizeof(buts)))
-+ return -EFAULT;
-+
-+ if (!buts.buf_size || !buts.buf_nr)
-+ return -EINVAL;
-+
-+ strcpy(buts.name, bdevname(bdev, b));
-+
-+ /*
-+ * 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;
-+
-+ down(&bdev->bd_sem);
-+ ret = -EBUSY;
-+ if (q->blk_trace)
-+ goto err;
-+
-+ ret = -ENOMEM;
-+ bt = kmalloc(sizeof(*bt), GFP_KERNEL);
-+ if (!bt)
-+ goto err;
-+
-+ ret = -ENOENT;
-+ dir = blk_create_tree(buts.name);
-+ if (!dir)
-+ goto err;
-+
-+ bt->dir = dir;
-+ bt->dev = bdev->bd_dev;
-+ bt->sequence = 0;
-+ spin_lock_init(&bt->lock);
-+ atomic_set(&bt->dropped, 0);
-+
-+ ret = -EIO;
-+ bt->dropped_file = relayfs_create_file("dropped", dir, 0, &blk_dropped_fops, bt);
-+ if (!bt->dropped_file)
-+ goto err;
-+
-+ bt->rchan = relay_open("trace", dir, buts.buf_size, buts.buf_nr, &blk_relay_callbacks);
-+ if (!bt->rchan)
-+ goto err;
-+ bt->rchan->private_data = bt;
-+
-+ 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;
-+
-+ q->blk_trace = bt;
-+ up(&bdev->bd_sem);
-+ return 0;
-+err:
-+ up(&bdev->bd_sem);
-+ if (bt && bt->dropped_file)
-+ relayfs_remove_file(bt->dropped_file);
-+ if (dir)
-+ blk_remove_tree(dir);
-+ if (bt)
-+ kfree(bt);
-+ return ret;
-+}
-+
-+/*
-+ * Average offset over two calls to sched_clock() with a gettimeofday()
-+ * in the middle
-+ */
-+static void blk_check_time(unsigned long long *t)
-+{
-+ unsigned long long a, b;
-+ struct timeval tv;
-+
-+ a = sched_clock();
-+ do_gettimeofday(&tv);
-+ b = sched_clock();
-+
-+ *t = tv.tv_sec * 1000000000 + tv.tv_usec * 1000;
-+ *t -= (a + b) / 2;
-+}
-+
-+static void blk_trace_check_cpu_time(void *data)
-+{
-+ unsigned long long *t;
-+ int cpu = get_cpu();
-+
-+ t = &per_cpu(blk_trace_cpu_offset, cpu);
-+
-+ /*
-+ * 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);
-+
-+ put_cpu();
-+}
-+
-+/*
-+ * Call blk_trace_check_cpu_time() on each CPU to calibrate our inter-CPU
-+ * timings
-+ */
-+static void blk_trace_calibrate_offsets(void)
-+{
-+ unsigned long flags;
-+
-+ smp_call_function(blk_trace_check_cpu_time, NULL, 1, 1);
-+ local_irq_save(flags);
-+ blk_trace_check_cpu_time(NULL);
-+ local_irq_restore(flags);
-+}
-+
-+static void blk_trace_set_ht_offsets(void)
-+{
-+#if defined(CONFIG_SCHED_SMT)
-+ int cpu, i;
-+
-+ /*
-+ * now make sure HT siblings have the same time offset
-+ */
-+ preempt_disable();
-+ for_each_online_cpu(cpu) {
-+ unsigned long long *cpu_off, *sibling_off;
-+
-+ for_each_cpu_mask(i, cpu_sibling_map[cpu]) {
-+ if (i == cpu)
-+ continue;
-+
-+ cpu_off = &per_cpu(blk_trace_cpu_offset, cpu);
-+ sibling_off = &per_cpu(blk_trace_cpu_offset, i);
-+ *sibling_off = *cpu_off;
-+ }
-+ }
-+ preempt_enable();
-+#endif
-+}
-+
-+static __init int blk_trace_init(void)
-+{
-+ mutex_init(&blk_tree_mutex);
-+ blk_trace_calibrate_offsets();
-+ blk_trace_set_ht_offsets();
-+
-+ return 0;
-+}
-+
-+module_init(blk_trace_init);
-+
-diff --git a/block/elevator.c b/block/elevator.c
-index c9f424d..793c686 100644
---- a/block/elevator.c
-+++ b/block/elevator.c
-@@ -33,6 +33,7 @@
- #include <linux/init.h>
- #include <linux/compiler.h>
- #include <linux/delay.h>
-+#include <linux/blktrace_api.h>
-
- #include <asm/uaccess.h>
-
-@@ -333,6 +334,8 @@ void __elv_add_request(request_queue_t *
- struct list_head *pos;
- unsigned ordseq;
-
-+ blk_add_trace_rq(q, rq, BLK_TA_INSERT);
-+
- if (q->ordcolor)
- rq->flags |= REQ_ORDERED_COLOR;
-
-@@ -491,6 +494,7 @@ struct request *elv_next_request(request
- * not be passed by new incoming requests
- */
- rq->flags |= REQ_STARTED;
-+ blk_add_trace_rq(q, rq, BLK_TA_ISSUE);
- }
-
- if (!q->boundary_rq || q->boundary_rq == rq) {
-diff --git a/block/ioctl.c b/block/ioctl.c
-index e110949..63e67a2 100644
---- a/block/ioctl.c
-+++ b/block/ioctl.c
-@@ -5,6 +5,7 @@
- #include <linux/backing-dev.h>
- #include <linux/buffer_head.h>
- #include <linux/smp_lock.h>
-+#include <linux/blktrace_api.h>
- #include <asm/uaccess.h>
-
- static int blkpg_ioctl(struct block_device *bdev, struct blkpg_ioctl_arg __user *arg)
-@@ -189,6 +190,10 @@ static int blkdev_locked_ioctl(struct fi
- return put_ulong(arg, bdev->bd_inode->i_size >> 9);
- case BLKGETSIZE64:
- return put_u64(arg, bdev->bd_inode->i_size);
-+ case BLKSTARTTRACE:
-+ return blk_start_trace(bdev, (char __user *) arg);
-+ case BLKSTOPTRACE:
-+ return blk_stop_trace(bdev);
- }
- return -ENOIOCTLCMD;
- }
-diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c
-index 8e27d0a..bfcde0f 100644
---- a/block/ll_rw_blk.c
-+++ b/block/ll_rw_blk.c
-@@ -28,6 +28,7 @@
- #include <linux/writeback.h>
- #include <linux/interrupt.h>
- #include <linux/cpu.h>
-+#include <linux/blktrace_api.h>
-
- /*
- * for max sense size
-@@ -1555,8 +1556,10 @@ void blk_plug_device(request_queue_t *q)
- if (test_bit(QUEUE_FLAG_STOPPED, &q->queue_flags))
- return;
-
-- if (!test_and_set_bit(QUEUE_FLAG_PLUGGED, &q->queue_flags))
-+ if (!test_and_set_bit(QUEUE_FLAG_PLUGGED, &q->queue_flags)) {
- mod_timer(&q->unplug_timer, jiffies + q->unplug_delay);
-+ blk_add_trace_generic(q, NULL, 0, BLK_TA_PLUG);
-+ }
- }
-
- EXPORT_SYMBOL(blk_plug_device);
-@@ -1620,14 +1623,21 @@ static void blk_backing_dev_unplug(struc
- /*
- * devices don't necessarily have an ->unplug_fn defined
- */
-- if (q->unplug_fn)
-+ if (q->unplug_fn) {
-+ blk_add_trace_pdu_int(q, BLK_TA_UNPLUG_IO, NULL,
-+ q->rq.count[READ] + q->rq.count[WRITE]);
-+
- q->unplug_fn(q);
-+ }
- }
-
- static void blk_unplug_work(void *data)
- {
- request_queue_t *q = data;
-
-+ blk_add_trace_pdu_int(q, BLK_TA_UNPLUG_IO, NULL,
-+ q->rq.count[READ] + q->rq.count[WRITE]);
-+
- q->unplug_fn(q);
- }
-
-@@ -1635,6 +1645,9 @@ static void blk_unplug_timeout(unsigned
- {
- request_queue_t *q = (request_queue_t *)data;
-
-+ blk_add_trace_pdu_int(q, BLK_TA_UNPLUG_TIMER, NULL,
-+ q->rq.count[READ] + q->rq.count[WRITE]);
-+
- kblockd_schedule_work(&q->unplug_work);
- }
-
-@@ -1757,6 +1770,11 @@ void blk_cleanup_queue(request_queue_t *
- if (q->queue_tags)
- __blk_queue_free_tags(q);
-
-+ if (q->blk_trace) {
-+ blk_cleanup_trace(q->blk_trace);
-+ q->blk_trace = NULL;
-+ }
-+
- kmem_cache_free(requestq_cachep, q);
- }
-
-@@ -2108,6 +2126,8 @@ rq_starved:
-
- rq_init(q, rq);
- rq->rl = rl;
-+
-+ blk_add_trace_generic(q, bio, rw, BLK_TA_GETRQ);
- out:
- return rq;
- }
-@@ -2136,6 +2156,8 @@ static struct request *get_request_wait(
- if (!rq) {
- struct io_context *ioc;
-
-+ blk_add_trace_generic(q, bio, rw, BLK_TA_SLEEPRQ);
-+
- __generic_unplug_device(q);
- spin_unlock_irq(q->queue_lock);
- io_schedule();
-@@ -2189,6 +2211,8 @@ EXPORT_SYMBOL(blk_get_request);
- */
- void blk_requeue_request(request_queue_t *q, struct request *rq)
- {
-+ blk_add_trace_rq(q, rq, BLK_TA_REQUEUE);
-+
- if (blk_rq_tagged(rq))
- blk_queue_end_tag(q, rq);
-
-@@ -2820,6 +2844,8 @@ static int __make_request(request_queue_
- if (!q->back_merge_fn(q, req, bio))
- break;
-
-+ blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE);
-+
- req->biotail->bi_next = bio;
- req->biotail = bio;
- req->nr_sectors = req->hard_nr_sectors += nr_sectors;
-@@ -2835,6 +2861,8 @@ static int __make_request(request_queue_
- if (!q->front_merge_fn(q, req, bio))
- break;
-
-+ blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE);
-+
- bio->bi_next = req->bio;
- req->bio = bio;
-
-@@ -2952,6 +2980,7 @@ void generic_make_request(struct bio *bi
- request_queue_t *q;
- sector_t maxsector;
- int ret, nr_sectors = bio_sectors(bio);
-+ dev_t old_dev;
-
- might_sleep();
- /* Test device or partition size, when known. */
-@@ -2978,6 +3007,8 @@ void generic_make_request(struct bio *bi
- * NOTE: we don't repeat the blk_size check for each new device.
- * Stacking drivers are expected to know what they are doing.
- */
-+ maxsector = -1;
-+ old_dev = 0;
- do {
- char b[BDEVNAME_SIZE];
-
-@@ -3010,6 +3041,15 @@ end_io:
- */
- blk_partition_remap(bio);
-
-+ if (maxsector != -1)
-+ blk_add_trace_remap(q, bio, old_dev, bio->bi_sector,
-+ maxsector);
-+
-+ blk_add_trace_bio(q, bio, BLK_TA_QUEUE);
-+
-+ maxsector = bio->bi_sector;
-+ old_dev = bio->bi_bdev->bd_dev;
-+
- ret = q->make_request_fn(q, bio);
- } while (ret);
- }
-@@ -3129,6 +3169,8 @@ static int __end_that_request_first(stru
- int total_bytes, bio_nbytes, error, next_idx = 0;
- struct bio *bio;
-
-+ blk_add_trace_rq(req->q, req, BLK_TA_COMPLETE);
-+
- /*
- * extend uptodate bool to allow < 0 value to be direct io error
- */
-diff --git a/drivers/block/cciss.c b/drivers/block/cciss.c
-index 12d7b9b..880892a 100644
---- a/drivers/block/cciss.c
-+++ b/drivers/block/cciss.c
-@@ -38,6 +38,7 @@
- #include <linux/hdreg.h>
- #include <linux/spinlock.h>
- #include <linux/compat.h>
-+#include <linux/blktrace_api.h>
- #include <asm/uaccess.h>
- #include <asm/io.h>
-
-@@ -2330,6 +2331,7 @@ static inline void complete_command( ctl
-
- cmd->rq->completion_data = cmd;
- cmd->rq->errors = status;
-+ blk_add_trace_rq(cmd->rq->q, cmd->rq, BLK_TA_COMPLETE);
- blk_complete_request(cmd->rq);
- }
-
-diff --git a/drivers/md/dm.c b/drivers/md/dm.c
-index 8c16359..8c979c2 100644
---- a/drivers/md/dm.c
-+++ b/drivers/md/dm.c
-@@ -17,6 +17,7 @@
- #include <linux/mempool.h>
- #include <linux/slab.h>
- #include <linux/idr.h>
-+#include <linux/blktrace_api.h>
-
- static const char *_name = DM_NAME;
-
-@@ -303,6 +304,8 @@ static void dec_pending(struct dm_io *io
- /* nudge anyone waiting on suspend queue */
- wake_up(&io->md->wait);
-
-+ blk_add_trace_bio(io->md->queue, io->bio, BLK_TA_COMPLETE);
-+
- bio_endio(io->bio, io->bio->bi_size, io->error);
- free_io(io->md, io);
- }
-@@ -361,6 +364,7 @@ static void __map_bio(struct dm_target *
- struct target_io *tio)
- {
- int r;
-+ sector_t sector;
-
- /*
- * Sanity checks.
-@@ -376,10 +380,17 @@ static void __map_bio(struct dm_target *
- * this io.
- */
- atomic_inc(&tio->io->io_count);
-+ sector = clone->bi_sector;
- r = ti->type->map(ti, clone, &tio->info);
-- if (r > 0)
-+ if (r > 0) {
- /* the bio has been remapped so dispatch it */
-+
-+ blk_add_trace_remap(bdev_get_queue(clone->bi_bdev), clone,
-+ tio->io->bio->bi_bdev->bd_dev, sector,
-+ clone->bi_sector);
-+
- generic_make_request(clone);
-+ }
-
- else if (r < 0) {
- /* error the io and bail out */
-diff --git a/fs/bio.c b/fs/bio.c
-index bbc442b..8a1b0b6 100644
---- a/fs/bio.c
-+++ b/fs/bio.c
-@@ -25,6 +25,7 @@
- #include <linux/module.h>
- #include <linux/mempool.h>
- #include <linux/workqueue.h>
-+#include <linux/blktrace_api.h>
- #include <scsi/sg.h> /* for struct sg_iovec */
-
- #define BIO_POOL_SIZE 256
-@@ -1094,6 +1095,9 @@ struct bio_pair *bio_split(struct bio *b
- if (!bp)
- return bp;
-
-+ blk_add_trace_pdu_int(bdev_get_queue(bi->bi_bdev), BLK_TA_SPLIT, bi,
-+ bi->bi_sector + first_sectors);
-+
- BUG_ON(bi->bi_vcnt != 1);
- BUG_ON(bi->bi_idx != 0);
- atomic_set(&bp->cnt, 3);
-diff --git a/fs/compat_ioctl.c b/fs/compat_ioctl.c
-index 5dd0207..010e02b 100644
---- a/fs/compat_ioctl.c
-+++ b/fs/compat_ioctl.c
-@@ -72,6 +72,7 @@
- #include <linux/i2c-dev.h>
- #include <linux/wireless.h>
- #include <linux/atalk.h>
-+#include <linux/blktrace_api.h>
-
- #include <net/sock.h> /* siocdevprivate_ioctl */
- #include <net/bluetooth/bluetooth.h>
-diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
-index 02a585f..195c3b9 100644
---- a/include/linux/blkdev.h
-+++ b/include/linux/blkdev.h
-@@ -22,6 +22,7 @@ typedef struct request_queue request_que
- struct elevator_queue;
- typedef struct elevator_queue elevator_t;
- struct request_pm_state;
-+struct blk_trace;
-
- #define BLKDEV_MIN_RQ 4
- #define BLKDEV_MAX_RQ 128 /* Default maximum */
-@@ -416,6 +417,8 @@ struct request_queue
- unsigned int sg_reserved_size;
- int node;
-
-+ struct blk_trace *blk_trace;
-+
- /*
- * reserved for flush operations
- */
-diff --git a/include/linux/blktrace_api.h b/include/linux/blktrace_api.h
-new file mode 100644
-index 0000000..d6b4317
---- /dev/null
-+++ b/include/linux/blktrace_api.h
-@@ -0,0 +1,216 @@
-+#ifndef BLKTRACE_H
-+#define BLKTRACE_H
-+
-+#include <linux/config.h>
-+#include <linux/blkdev.h>
-+#include <linux/relayfs_fs.h>
-+
-+/*
-+ * Trace categories
-+ */
-+enum blktrace_cat {
-+ BLK_TC_READ = 1 << 0, /* reads */
-+ BLK_TC_WRITE = 1 << 1, /* writes */
-+ BLK_TC_BARRIER = 1 << 2, /* barrier */
-+ BLK_TC_SYNC = 1 << 3, /* barrier */
-+ BLK_TC_QUEUE = 1 << 4, /* queueing/merging */
-+ BLK_TC_REQUEUE = 1 << 5, /* requeueing */
-+ BLK_TC_ISSUE = 1 << 6, /* issue */
-+ BLK_TC_COMPLETE = 1 << 7, /* completions */
-+ BLK_TC_FS = 1 << 8, /* fs requests */
-+ BLK_TC_PC = 1 << 9, /* pc requests */
-+
-+ BLK_TC_END = 1 << 15, /* only 16-bits, reminder */
-+};
-+
-+#define BLK_TC_SHIFT (16)
-+#define BLK_TC_ACT(act) ((act) << BLK_TC_SHIFT)
-+
-+/*
-+ * Basic trace actions
-+ */
-+enum blktrace_act {
-+ __BLK_TA_QUEUE = 1, /* queued */
-+ __BLK_TA_BACKMERGE, /* back merged to existing rq */
-+ __BLK_TA_FRONTMERGE, /* front merge to existing rq */
-+ __BLK_TA_GETRQ, /* allocated new request */
-+ __BLK_TA_SLEEPRQ, /* sleeping on rq allocation */
-+ __BLK_TA_REQUEUE, /* request requeued */
-+ __BLK_TA_ISSUE, /* sent to driver */
-+ __BLK_TA_COMPLETE, /* completed by driver */
-+ __BLK_TA_PLUG, /* queue was plugged */
-+ __BLK_TA_UNPLUG_IO, /* queue was unplugged by io */
-+ __BLK_TA_UNPLUG_TIMER, /* queue was unplugged by timer */
-+ __BLK_TA_INSERT, /* insert request */
-+ __BLK_TA_SPLIT, /* bio was split */
-+ __BLK_TA_BOUNCE, /* bio was bounced */
-+ __BLK_TA_REMAP, /* bio was remapped */
-+};
-+
-+/*
-+ * Trace actions in full. Additionally, read or write is masked
-+ */
-+#define BLK_TA_QUEUE (__BLK_TA_QUEUE | BLK_TC_ACT(BLK_TC_QUEUE))
-+#define BLK_TA_BACKMERGE (__BLK_TA_BACKMERGE | BLK_TC_ACT(BLK_TC_QUEUE))
-+#define BLK_TA_FRONTMERGE (__BLK_TA_FRONTMERGE | BLK_TC_ACT(BLK_TC_QUEUE))
-+#define BLK_TA_GETRQ (__BLK_TA_GETRQ | BLK_TC_ACT(BLK_TC_QUEUE))
-+#define BLK_TA_SLEEPRQ (__BLK_TA_SLEEPRQ | BLK_TC_ACT(BLK_TC_QUEUE))
-+#define BLK_TA_REQUEUE (__BLK_TA_REQUEUE | BLK_TC_ACT(BLK_TC_REQUEUE))
-+#define BLK_TA_ISSUE (__BLK_TA_ISSUE | BLK_TC_ACT(BLK_TC_ISSUE))
-+#define BLK_TA_COMPLETE (__BLK_TA_COMPLETE| BLK_TC_ACT(BLK_TC_COMPLETE))
-+#define BLK_TA_PLUG (__BLK_TA_PLUG | BLK_TC_ACT(BLK_TC_QUEUE))
-+#define BLK_TA_UNPLUG_IO (__BLK_TA_UNPLUG_IO | BLK_TC_ACT(BLK_TC_QUEUE))
-+#define BLK_TA_UNPLUG_TIMER (__BLK_TA_UNPLUG_TIMER | BLK_TC_ACT(BLK_TC_QUEUE))
-+#define BLK_TA_INSERT (__BLK_TA_INSERT | BLK_TC_ACT(BLK_TC_QUEUE))
-+#define BLK_TA_SPLIT (__BLK_TA_SPLIT)
-+#define BLK_TA_BOUNCE (__BLK_TA_BOUNCE)
-+#define BLK_TA_REMAP (__BLK_TA_REMAP | BLK_TC_ACT(BLK_TC_QUEUE))
-+
-+#define BLK_IO_TRACE_MAGIC 0x65617400
-+#define BLK_IO_TRACE_VERSION 0x05
-+
-+/*
-+ * The trace itself
-+ */
-+struct blk_io_trace {
-+ u32 magic; /* MAGIC << 8 | version */
-+ u32 sequence; /* event number */
-+ u64 time; /* in microseconds */
-+ u64 sector; /* disk offset */
-+ u32 bytes; /* transfer length */
-+ u32 action; /* what happened */
-+ u32 pid; /* who did it */
-+ u32 cpu; /* on what cpu did it happen */
-+ u16 error; /* completion error */
-+ u16 pdu_len; /* length of data after this trace */
-+ u32 device; /* device number */
-+ char comm[16]; /* task command name (TASK_COMM_LEN) */
-+};
-+
-+/*
-+ * The remap event
-+ */
-+struct blk_io_trace_remap {
-+ u32 device;
-+ u32 __pad;
-+ u64 sector;
-+};
-+
-+struct blk_trace {
-+ struct dentry *dir;
-+ struct rchan *rchan;
-+ struct dentry *dropped_file;
-+ atomic_t dropped;
-+ spinlock_t lock;
-+ unsigned long sequence;
-+ u32 dev;
-+ u16 act_mask;
-+ u64 start_lba;
-+ u64 end_lba;
-+ u32 pid;
-+};
-+
-+/*
-+ * User setup structure passed with BLKSTARTTRACE
-+ */
-+struct blk_user_trace_setup {
-+ char name[BDEVNAME_SIZE]; /* output */
-+ u16 act_mask; /* input */
-+ u32 buf_size; /* input */
-+ u32 buf_nr; /* input */
-+ u64 start_lba;
-+ u64 end_lba;
-+ u32 pid;
-+};
-+
-+#if defined(CONFIG_BLK_DEV_IO_TRACE)
-+extern int blk_start_trace(struct block_device *, char __user *);
-+extern int blk_stop_trace(struct block_device *);
-+extern void blk_cleanup_trace(struct blk_trace *);
-+extern void __blk_add_trace(struct blk_trace *, sector_t, int, int, u32, int, int, void *);
-+
-+static inline void blk_add_trace_rq(struct request_queue *q, struct request *rq,
-+ u32 what)
-+{
-+ struct blk_trace *bt = q->blk_trace;
-+ int rw = rq->flags & 0x07;
-+
-+ if (likely(!bt))
-+ return;
-+
-+ 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 inline 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 inline void blk_add_trace_generic(struct request_queue *q,
-+ struct bio *bio, int rw, u32 what)
-+{
-+ struct blk_trace *bt = q->blk_trace;
-+
-+ if (likely(!bt))
-+ return;
-+
-+ if (bio)
-+ blk_add_trace_bio(q, bio, what);
-+ else
-+ __blk_add_trace(bt, 0, 0, rw, what, 0, 0, NULL);
-+}
-+
-+static inline void blk_add_trace_pdu_int(struct request_queue *q, u32 what,
-+ struct bio *bio, unsigned int pdu)
-+{
-+ struct blk_trace *bt = q->blk_trace;
-+ u64 rpdu = cpu_to_be64(pdu);
-+
-+ if (likely(!bt))
-+ return;
-+
-+ if (bio)
-+ __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, what, !bio_flagged(bio, BIO_UPTODATE), sizeof(rpdu), &rpdu);
-+ else
-+ __blk_add_trace(bt, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu);
-+}
-+
-+static inline 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.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);
-+}
-+
-+#else /* !CONFIG_BLK_DEV_IO_TRACE */
-+#define blk_start_trace(bdev, arg) (-EINVAL)
-+#define blk_stop_trace(bdev) (-EINVAL)
-+#define blk_cleanup_trace(bt) do { } while (0)
-+#define blk_add_trace_rq(q, rq, what) do { } while (0)
-+#define blk_add_trace_bio(q, rq, what) do { } while (0)
-+#define blk_add_trace_generic(q, rq, rw, what) do { } while (0)
-+#define blk_add_trace_pdu_int(q, what, bio, pdu) do { } while (0)
-+#define blk_add_trace_remap(q, bio, dev, f, t) do {} while (0)
-+#endif /* CONFIG_BLK_DEV_IO_TRACE */
-+
-+#endif
-diff --git a/include/linux/compat_ioctl.h b/include/linux/compat_ioctl.h
-index 8fad50f..5bed09a 100644
---- a/include/linux/compat_ioctl.h
-+++ b/include/linux/compat_ioctl.h
-@@ -97,6 +97,8 @@ COMPATIBLE_IOCTL(BLKRRPART)
- COMPATIBLE_IOCTL(BLKFLSBUF)
- COMPATIBLE_IOCTL(BLKSECTSET)
- COMPATIBLE_IOCTL(BLKSSZGET)
-+COMPATIBLE_IOCTL(BLKSTARTTRACE)
-+COMPATIBLE_IOCTL(BLKSTOPTRACE)
- ULONG_IOCTL(BLKRASET)
- ULONG_IOCTL(BLKFRASET)
- /* RAID */
-diff --git a/include/linux/fs.h b/include/linux/fs.h
-index b77f260..5575284 100644
---- a/include/linux/fs.h
-+++ b/include/linux/fs.h
-@@ -196,6 +196,8 @@ extern int dir_notify_enable;
- #define BLKBSZGET _IOR(0x12,112,size_t)
- #define BLKBSZSET _IOW(0x12,113,size_t)
- #define BLKGETSIZE64 _IOR(0x12,114,size_t) /* return device size in bytes (u64 *arg) */
-+#define BLKSTARTTRACE _IOWR(0x12,115,struct blk_user_trace_setup)
-+#define BLKSTOPTRACE _IO(0x12,116)
-
- #define BMAP_IOCTL 1 /* obsolete - kept for compatibility */
- #define FIBMAP _IO(0x00,1) /* bmap access */
-diff --git a/mm/highmem.c b/mm/highmem.c
-index ce2e7e8..d0ea1ee 100644
---- a/mm/highmem.c
-+++ b/mm/highmem.c
-@@ -26,6 +26,7 @@
- #include <linux/init.h>
- #include <linux/hash.h>
- #include <linux/highmem.h>
-+#include <linux/blktrace_api.h>
- #include <asm/tlbflush.h>
-
- static mempool_t *page_pool, *isa_page_pool;
-@@ -483,6 +484,8 @@ void blk_queue_bounce(request_queue_t *q
- pool = isa_page_pool;
- }
-
-+ blk_add_trace_bio(q, *bio_orig, BLK_TA_BOUNCE);
-+
- /*
- * slow path
- */
--- /dev/null
+diff --git a/block/Kconfig b/block/Kconfig
+index 377f6dd..27eaed9 100644
+--- a/block/Kconfig
++++ b/block/Kconfig
+@@ -11,4 +11,15 @@ config LBD
+ your machine, or if you want to have a raid or loopback device
+ bigger than 2TB. Otherwise say N.
+
++config BLK_DEV_IO_TRACE
++ bool "Support for tracing block io actions"
++ select RELAYFS_FS
++ 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 user space
++ support tools needed), fetch the blktrace app from:
++
++ git://brick.kernel.dk/data/git/blktrace.git
++
+ source block/Kconfig.iosched
+diff --git a/block/Makefile b/block/Makefile
+index 7e4f93e..c05de0e 100644
+--- a/block/Makefile
++++ b/block/Makefile
+@@ -8,3 +8,5 @@ obj-$(CONFIG_IOSCHED_NOOP) += noop-iosch
+ obj-$(CONFIG_IOSCHED_AS) += as-iosched.o
+ obj-$(CONFIG_IOSCHED_DEADLINE) += deadline-iosched.o
+ obj-$(CONFIG_IOSCHED_CFQ) += cfq-iosched.o
++
++obj-$(CONFIG_BLK_DEV_IO_TRACE) += blktrace.o
+diff --git a/block/blktrace.c b/block/blktrace.c
+new file mode 100644
+index 0000000..21b381d
+--- /dev/null
++++ b/block/blktrace.c
+@@ -0,0 +1,362 @@
++#include <linux/config.h>
++#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 <asm/uaccess.h>
++
++static DEFINE_PER_CPU(unsigned long long, blk_trace_cpu_offset) = { 0, };
++
++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 blk_io_trace *t;
++ unsigned long flags;
++ unsigned long *sequence;
++ pid_t pid;
++ int cpu;
++
++ if (rw & (1 << BIO_RW_BARRIER))
++ what |= BLK_TC_ACT(BLK_TC_BARRIER);
++ if (rw & (1 << BIO_RW_SYNC))
++ what |= BLK_TC_ACT(BLK_TC_SYNC);
++
++ if (rw & WRITE)
++ what |= BLK_TC_ACT(BLK_TC_WRITE);
++ else
++ what |= BLK_TC_ACT(BLK_TC_READ);
++
++ if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0)
++ return;
++ if (sector < bt->start_lba || sector > bt->end_lba)
++ return;
++
++ pid = current->pid;
++ if (bt->pid && pid != bt->pid)
++ return;
++
++ local_irq_save(flags);
++
++ t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len);
++ if (unlikely(!t)) {
++ local_irq_restore(flags);
++ return;
++ }
++
++ cpu = smp_processor_id();
++ sequence = per_cpu_ptr(bt->sequence, cpu);
++ t->sequence = ++(*sequence);
++ t->time = sched_clock() - per_cpu(blk_trace_cpu_offset, cpu);
++ t->cpu = cpu;
++
++ local_irq_restore(flags);
++
++ t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
++ t->device = bt->dev;
++ t->sector = sector;
++ t->bytes = bytes;
++ t->action = what;
++ t->error = error;
++ t->pdu_len = pdu_len;
++
++ t->pid = pid;
++ memcpy(t->comm, current->comm, sizeof(t->comm));
++
++ if (pdu_len)
++ memcpy((void *) t + sizeof(*t), pdu_data, pdu_len);
++}
++
++EXPORT_SYMBOL_GPL(__blk_add_trace);
++
++static struct dentry *blk_tree_root;
++static struct mutex blk_tree_mutex;
++
++static inline void blk_remove_root(void)
++{
++ if (relayfs_remove_dir(blk_tree_root) != -ENOTEMPTY)
++ blk_tree_root = NULL;
++}
++
++static void blk_remove_tree(struct dentry *dir)
++{
++ mutex_lock(&blk_tree_mutex);
++ relayfs_remove_dir(dir);
++ 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 = relayfs_create_dir("block", NULL);
++ if (!blk_tree_root)
++ goto err;
++ }
++
++ dir = relayfs_create_dir(blk_name, blk_tree_root);
++ if (!dir)
++ blk_remove_root();
++
++err:
++ mutex_unlock(&blk_tree_mutex);
++ return dir;
++}
++
++void blk_cleanup_trace(struct blk_trace *bt)
++{
++ relay_close(bt->rchan);
++ relayfs_remove_file(bt->dropped_file);
++ blk_remove_tree(bt->dir);
++ kfree(bt);
++}
++
++int blk_stop_trace(struct block_device *bdev)
++{
++ request_queue_t *q = bdev_get_queue(bdev);
++ struct blk_trace *bt = NULL;
++ int ret = -EINVAL;
++
++ if (!q)
++ return -ENXIO;
++
++ down(&bdev->bd_sem);
++
++ if (q->blk_trace) {
++ bt = q->blk_trace;
++ q->blk_trace = NULL;
++ ret = 0;
++ }
++
++ up(&bdev->bd_sem);
++
++ if (bt)
++ blk_cleanup_trace(bt);
++
++ return ret;
++}
++
++static int blk_dropped_open(struct inode *inode, struct file *filp)
++{
++ filp->private_data = inode->u.generic_ip;
++
++ 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 struct file_operations blk_dropped_fops = {
++ .owner = THIS_MODULE,
++ .open = blk_dropped_open,
++ .read = blk_dropped_read,
++};
++
++static int blk_subbuf_start_callback (struct rchan_buf *buf,
++ void *subbuf,
++ void *prev_subbuf,
++ size_t prev_padding)
++{
++ if (relay_buf_full(buf)) {
++ struct blk_trace *bt = buf->chan->private_data;
++
++ atomic_inc(&bt->dropped);
++ return 0;
++ }
++
++ return 1;
++}
++
++static struct rchan_callbacks blk_relay_callbacks = {
++ .subbuf_start = blk_subbuf_start_callback,
++};
++
++int blk_start_trace(struct block_device *bdev, char __user *arg)
++{
++ request_queue_t *q = bdev_get_queue(bdev);
++ struct blk_user_trace_setup buts;
++ struct blk_trace *bt = NULL;
++ struct dentry *dir = NULL;
++ char b[BDEVNAME_SIZE];
++ int ret, i;
++
++ if (!q)
++ return -ENXIO;
++
++ if (copy_from_user(&buts, arg, sizeof(buts)))
++ return -EFAULT;
++
++ if (!buts.buf_size || !buts.buf_nr)
++ return -EINVAL;
++
++ strcpy(buts.name, bdevname(bdev, b));
++
++ /*
++ * 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;
++
++ down(&bdev->bd_sem);
++ ret = -EBUSY;
++ if (q->blk_trace)
++ goto err;
++
++ ret = -ENOMEM;
++ bt = kzalloc(sizeof(*bt), GFP_KERNEL);
++ if (!bt)
++ goto err;
++
++ bt->sequence = alloc_percpu(unsigned long);
++ if (!bt->sequence)
++ goto err;
++
++ ret = -ENOENT;
++ dir = blk_create_tree(buts.name);
++ if (!dir)
++ goto err;
++
++ bt->dir = dir;
++ bt->dev = bdev->bd_dev;
++ atomic_set(&bt->dropped, 0);
++
++ ret = -EIO;
++ bt->dropped_file = relayfs_create_file("dropped", dir, 0, &blk_dropped_fops, bt);
++ if (!bt->dropped_file)
++ goto err;
++
++ bt->rchan = relay_open("trace", dir, buts.buf_size, buts.buf_nr, &blk_relay_callbacks);
++ if (!bt->rchan)
++ goto err;
++ bt->rchan->private_data = bt;
++
++ 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;
++
++ q->blk_trace = bt;
++ up(&bdev->bd_sem);
++ return 0;
++err:
++ up(&bdev->bd_sem);
++ if (bt && bt->dropped_file)
++ relayfs_remove_file(bt->dropped_file);
++ if (dir)
++ blk_remove_tree(dir);
++ if (bt) {
++ if (bt->sequence)
++ free_percpu(bt->sequence);
++ kfree(bt);
++ }
++ return ret;
++}
++
++/*
++ * Average offset over two calls to sched_clock() with a gettimeofday()
++ * in the middle
++ */
++static void blk_check_time(unsigned long long *t)
++{
++ unsigned long long a, b;
++ struct timeval tv;
++
++ a = sched_clock();
++ do_gettimeofday(&tv);
++ b = sched_clock();
++
++ *t = tv.tv_sec * 1000000000 + tv.tv_usec * 1000;
++ *t -= (a + b) / 2;
++}
++
++static void blk_trace_check_cpu_time(void *data)
++{
++ unsigned long long *t;
++ int cpu = get_cpu();
++
++ t = &per_cpu(blk_trace_cpu_offset, cpu);
++
++ /*
++ * 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);
++
++ put_cpu();
++}
++
++/*
++ * Call blk_trace_check_cpu_time() on each CPU to calibrate our inter-CPU
++ * timings
++ */
++static void blk_trace_calibrate_offsets(void)
++{
++ unsigned long flags;
++
++ smp_call_function(blk_trace_check_cpu_time, NULL, 1, 1);
++ local_irq_save(flags);
++ blk_trace_check_cpu_time(NULL);
++ local_irq_restore(flags);
++}
++
++static void blk_trace_set_ht_offsets(void)
++{
++#if defined(CONFIG_SCHED_SMT)
++ int cpu, i;
++
++ /*
++ * now make sure HT siblings have the same time offset
++ */
++ preempt_disable();
++ for_each_online_cpu(cpu) {
++ unsigned long long *cpu_off, *sibling_off;
++
++ for_each_cpu_mask(i, cpu_sibling_map[cpu]) {
++ if (i == cpu)
++ continue;
++
++ cpu_off = &per_cpu(blk_trace_cpu_offset, cpu);
++ sibling_off = &per_cpu(blk_trace_cpu_offset, i);
++ *sibling_off = *cpu_off;
++ }
++ }
++ preempt_enable();
++#endif
++}
++
++static __init int blk_trace_init(void)
++{
++ mutex_init(&blk_tree_mutex);
++ blk_trace_calibrate_offsets();
++ blk_trace_set_ht_offsets();
++
++ return 0;
++}
++
++module_init(blk_trace_init);
++
+diff --git a/block/elevator.c b/block/elevator.c
+index c9f424d..793c686 100644
+--- a/block/elevator.c
++++ b/block/elevator.c
+@@ -33,6 +33,7 @@
+ #include <linux/init.h>
+ #include <linux/compiler.h>
+ #include <linux/delay.h>
++#include <linux/blktrace_api.h>
+
+ #include <asm/uaccess.h>
+
+@@ -333,6 +334,8 @@ void __elv_add_request(request_queue_t *
+ struct list_head *pos;
+ unsigned ordseq;
+
++ blk_add_trace_rq(q, rq, BLK_TA_INSERT);
++
+ if (q->ordcolor)
+ rq->flags |= REQ_ORDERED_COLOR;
+
+@@ -491,6 +494,7 @@ struct request *elv_next_request(request
+ * not be passed by new incoming requests
+ */
+ rq->flags |= REQ_STARTED;
++ blk_add_trace_rq(q, rq, BLK_TA_ISSUE);
+ }
+
+ if (!q->boundary_rq || q->boundary_rq == rq) {
+diff --git a/block/ioctl.c b/block/ioctl.c
+index e110949..63e67a2 100644
+--- a/block/ioctl.c
++++ b/block/ioctl.c
+@@ -5,6 +5,7 @@
+ #include <linux/backing-dev.h>
+ #include <linux/buffer_head.h>
+ #include <linux/smp_lock.h>
++#include <linux/blktrace_api.h>
+ #include <asm/uaccess.h>
+
+ static int blkpg_ioctl(struct block_device *bdev, struct blkpg_ioctl_arg __user *arg)
+@@ -189,6 +190,10 @@ static int blkdev_locked_ioctl(struct fi
+ return put_ulong(arg, bdev->bd_inode->i_size >> 9);
+ case BLKGETSIZE64:
+ return put_u64(arg, bdev->bd_inode->i_size);
++ case BLKSTARTTRACE:
++ return blk_start_trace(bdev, (char __user *) arg);
++ case BLKSTOPTRACE:
++ return blk_stop_trace(bdev);
+ }
+ return -ENOIOCTLCMD;
+ }
+diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c
+index 8e27d0a..bfcde0f 100644
+--- a/block/ll_rw_blk.c
++++ b/block/ll_rw_blk.c
+@@ -28,6 +28,7 @@
+ #include <linux/writeback.h>
+ #include <linux/interrupt.h>
+ #include <linux/cpu.h>
++#include <linux/blktrace_api.h>
+
+ /*
+ * for max sense size
+@@ -1555,8 +1556,10 @@ void blk_plug_device(request_queue_t *q)
+ if (test_bit(QUEUE_FLAG_STOPPED, &q->queue_flags))
+ return;
+
+- if (!test_and_set_bit(QUEUE_FLAG_PLUGGED, &q->queue_flags))
++ if (!test_and_set_bit(QUEUE_FLAG_PLUGGED, &q->queue_flags)) {
+ mod_timer(&q->unplug_timer, jiffies + q->unplug_delay);
++ blk_add_trace_generic(q, NULL, 0, BLK_TA_PLUG);
++ }
+ }
+
+ EXPORT_SYMBOL(blk_plug_device);
+@@ -1620,14 +1623,21 @@ static void blk_backing_dev_unplug(struc
+ /*
+ * devices don't necessarily have an ->unplug_fn defined
+ */
+- if (q->unplug_fn)
++ if (q->unplug_fn) {
++ blk_add_trace_pdu_int(q, BLK_TA_UNPLUG_IO, NULL,
++ q->rq.count[READ] + q->rq.count[WRITE]);
++
+ q->unplug_fn(q);
++ }
+ }
+
+ static void blk_unplug_work(void *data)
+ {
+ request_queue_t *q = data;
+
++ blk_add_trace_pdu_int(q, BLK_TA_UNPLUG_IO, NULL,
++ q->rq.count[READ] + q->rq.count[WRITE]);
++
+ q->unplug_fn(q);
+ }
+
+@@ -1635,6 +1645,9 @@ static void blk_unplug_timeout(unsigned
+ {
+ request_queue_t *q = (request_queue_t *)data;
+
++ blk_add_trace_pdu_int(q, BLK_TA_UNPLUG_TIMER, NULL,
++ q->rq.count[READ] + q->rq.count[WRITE]);
++
+ kblockd_schedule_work(&q->unplug_work);
+ }
+
+@@ -1757,6 +1770,11 @@ void blk_cleanup_queue(request_queue_t *
+ if (q->queue_tags)
+ __blk_queue_free_tags(q);
+
++ if (q->blk_trace) {
++ blk_cleanup_trace(q->blk_trace);
++ q->blk_trace = NULL;
++ }
++
+ kmem_cache_free(requestq_cachep, q);
+ }
+
+@@ -2108,6 +2126,8 @@ rq_starved:
+
+ rq_init(q, rq);
+ rq->rl = rl;
++
++ blk_add_trace_generic(q, bio, rw, BLK_TA_GETRQ);
+ out:
+ return rq;
+ }
+@@ -2136,6 +2156,8 @@ static struct request *get_request_wait(
+ if (!rq) {
+ struct io_context *ioc;
+
++ blk_add_trace_generic(q, bio, rw, BLK_TA_SLEEPRQ);
++
+ __generic_unplug_device(q);
+ spin_unlock_irq(q->queue_lock);
+ io_schedule();
+@@ -2189,6 +2211,8 @@ EXPORT_SYMBOL(blk_get_request);
+ */
+ void blk_requeue_request(request_queue_t *q, struct request *rq)
+ {
++ blk_add_trace_rq(q, rq, BLK_TA_REQUEUE);
++
+ if (blk_rq_tagged(rq))
+ blk_queue_end_tag(q, rq);
+
+@@ -2820,6 +2844,8 @@ static int __make_request(request_queue_
+ if (!q->back_merge_fn(q, req, bio))
+ break;
+
++ blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE);
++
+ req->biotail->bi_next = bio;
+ req->biotail = bio;
+ req->nr_sectors = req->hard_nr_sectors += nr_sectors;
+@@ -2835,6 +2861,8 @@ static int __make_request(request_queue_
+ if (!q->front_merge_fn(q, req, bio))
+ break;
+
++ blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE);
++
+ bio->bi_next = req->bio;
+ req->bio = bio;
+
+@@ -2952,6 +2980,7 @@ void generic_make_request(struct bio *bi
+ request_queue_t *q;
+ sector_t maxsector;
+ int ret, nr_sectors = bio_sectors(bio);
++ dev_t old_dev;
+
+ might_sleep();
+ /* Test device or partition size, when known. */
+@@ -2978,6 +3007,8 @@ void generic_make_request(struct bio *bi
+ * NOTE: we don't repeat the blk_size check for each new device.
+ * Stacking drivers are expected to know what they are doing.
+ */
++ maxsector = -1;
++ old_dev = 0;
+ do {
+ char b[BDEVNAME_SIZE];
+
+@@ -3010,6 +3041,15 @@ end_io:
+ */
+ blk_partition_remap(bio);
+
++ if (maxsector != -1)
++ blk_add_trace_remap(q, bio, old_dev, bio->bi_sector,
++ maxsector);
++
++ blk_add_trace_bio(q, bio, BLK_TA_QUEUE);
++
++ maxsector = bio->bi_sector;
++ old_dev = bio->bi_bdev->bd_dev;
++
+ ret = q->make_request_fn(q, bio);
+ } while (ret);
+ }
+@@ -3129,6 +3169,8 @@ static int __end_that_request_first(stru
+ int total_bytes, bio_nbytes, error, next_idx = 0;
+ struct bio *bio;
+
++ blk_add_trace_rq(req->q, req, BLK_TA_COMPLETE);
++
+ /*
+ * extend uptodate bool to allow < 0 value to be direct io error
+ */
+diff --git a/drivers/block/cciss.c b/drivers/block/cciss.c
+index 12d7b9b..880892a 100644
+--- a/drivers/block/cciss.c
++++ b/drivers/block/cciss.c
+@@ -38,6 +38,7 @@
+ #include <linux/hdreg.h>
+ #include <linux/spinlock.h>
+ #include <linux/compat.h>
++#include <linux/blktrace_api.h>
+ #include <asm/uaccess.h>
+ #include <asm/io.h>
+
+@@ -2330,6 +2331,7 @@ static inline void complete_command( ctl
+
+ cmd->rq->completion_data = cmd;
+ cmd->rq->errors = status;
++ blk_add_trace_rq(cmd->rq->q, cmd->rq, BLK_TA_COMPLETE);
+ blk_complete_request(cmd->rq);
+ }
+
+diff --git a/drivers/md/dm.c b/drivers/md/dm.c
+index 8c16359..8c979c2 100644
+--- a/drivers/md/dm.c
++++ b/drivers/md/dm.c
+@@ -17,6 +17,7 @@
+ #include <linux/mempool.h>
+ #include <linux/slab.h>
+ #include <linux/idr.h>
++#include <linux/blktrace_api.h>
+
+ static const char *_name = DM_NAME;
+
+@@ -303,6 +304,8 @@ static void dec_pending(struct dm_io *io
+ /* nudge anyone waiting on suspend queue */
+ wake_up(&io->md->wait);
+
++ blk_add_trace_bio(io->md->queue, io->bio, BLK_TA_COMPLETE);
++
+ bio_endio(io->bio, io->bio->bi_size, io->error);
+ free_io(io->md, io);
+ }
+@@ -361,6 +364,7 @@ static void __map_bio(struct dm_target *
+ struct target_io *tio)
+ {
+ int r;
++ sector_t sector;
+
+ /*
+ * Sanity checks.
+@@ -376,10 +380,17 @@ static void __map_bio(struct dm_target *
+ * this io.
+ */
+ atomic_inc(&tio->io->io_count);
++ sector = clone->bi_sector;
+ r = ti->type->map(ti, clone, &tio->info);
+- if (r > 0)
++ if (r > 0) {
+ /* the bio has been remapped so dispatch it */
++
++ blk_add_trace_remap(bdev_get_queue(clone->bi_bdev), clone,
++ tio->io->bio->bi_bdev->bd_dev, sector,
++ clone->bi_sector);
++
+ generic_make_request(clone);
++ }
+
+ else if (r < 0) {
+ /* error the io and bail out */
+diff --git a/fs/bio.c b/fs/bio.c
+index bbc442b..8a1b0b6 100644
+--- a/fs/bio.c
++++ b/fs/bio.c
+@@ -25,6 +25,7 @@
+ #include <linux/module.h>
+ #include <linux/mempool.h>
+ #include <linux/workqueue.h>
++#include <linux/blktrace_api.h>
+ #include <scsi/sg.h> /* for struct sg_iovec */
+
+ #define BIO_POOL_SIZE 256
+@@ -1094,6 +1095,9 @@ struct bio_pair *bio_split(struct bio *b
+ if (!bp)
+ return bp;
+
++ blk_add_trace_pdu_int(bdev_get_queue(bi->bi_bdev), BLK_TA_SPLIT, bi,
++ bi->bi_sector + first_sectors);
++
+ BUG_ON(bi->bi_vcnt != 1);
+ BUG_ON(bi->bi_idx != 0);
+ atomic_set(&bp->cnt, 3);
+diff --git a/fs/compat_ioctl.c b/fs/compat_ioctl.c
+index 5dd0207..010e02b 100644
+--- a/fs/compat_ioctl.c
++++ b/fs/compat_ioctl.c
+@@ -72,6 +72,7 @@
+ #include <linux/i2c-dev.h>
+ #include <linux/wireless.h>
+ #include <linux/atalk.h>
++#include <linux/blktrace_api.h>
+
+ #include <net/sock.h> /* siocdevprivate_ioctl */
+ #include <net/bluetooth/bluetooth.h>
+diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
+index 02a585f..195c3b9 100644
+--- a/include/linux/blkdev.h
++++ b/include/linux/blkdev.h
+@@ -22,6 +22,7 @@ typedef struct request_queue request_que
+ struct elevator_queue;
+ typedef struct elevator_queue elevator_t;
+ struct request_pm_state;
++struct blk_trace;
+
+ #define BLKDEV_MIN_RQ 4
+ #define BLKDEV_MAX_RQ 128 /* Default maximum */
+@@ -416,6 +417,8 @@ struct request_queue
+ unsigned int sg_reserved_size;
+ int node;
+
++ struct blk_trace *blk_trace;
++
+ /*
+ * reserved for flush operations
+ */
+diff --git a/include/linux/blktrace_api.h b/include/linux/blktrace_api.h
+new file mode 100644
+index 0000000..026b995
+--- /dev/null
++++ b/include/linux/blktrace_api.h
+@@ -0,0 +1,215 @@
++#ifndef BLKTRACE_H
++#define BLKTRACE_H
++
++#include <linux/config.h>
++#include <linux/blkdev.h>
++#include <linux/relayfs_fs.h>
++
++/*
++ * Trace categories
++ */
++enum blktrace_cat {
++ BLK_TC_READ = 1 << 0, /* reads */
++ BLK_TC_WRITE = 1 << 1, /* writes */
++ BLK_TC_BARRIER = 1 << 2, /* barrier */
++ BLK_TC_SYNC = 1 << 3, /* barrier */
++ BLK_TC_QUEUE = 1 << 4, /* queueing/merging */
++ BLK_TC_REQUEUE = 1 << 5, /* requeueing */
++ BLK_TC_ISSUE = 1 << 6, /* issue */
++ BLK_TC_COMPLETE = 1 << 7, /* completions */
++ BLK_TC_FS = 1 << 8, /* fs requests */
++ BLK_TC_PC = 1 << 9, /* pc requests */
++
++ BLK_TC_END = 1 << 15, /* only 16-bits, reminder */
++};
++
++#define BLK_TC_SHIFT (16)
++#define BLK_TC_ACT(act) ((act) << BLK_TC_SHIFT)
++
++/*
++ * Basic trace actions
++ */
++enum blktrace_act {
++ __BLK_TA_QUEUE = 1, /* queued */
++ __BLK_TA_BACKMERGE, /* back merged to existing rq */
++ __BLK_TA_FRONTMERGE, /* front merge to existing rq */
++ __BLK_TA_GETRQ, /* allocated new request */
++ __BLK_TA_SLEEPRQ, /* sleeping on rq allocation */
++ __BLK_TA_REQUEUE, /* request requeued */
++ __BLK_TA_ISSUE, /* sent to driver */
++ __BLK_TA_COMPLETE, /* completed by driver */
++ __BLK_TA_PLUG, /* queue was plugged */
++ __BLK_TA_UNPLUG_IO, /* queue was unplugged by io */
++ __BLK_TA_UNPLUG_TIMER, /* queue was unplugged by timer */
++ __BLK_TA_INSERT, /* insert request */
++ __BLK_TA_SPLIT, /* bio was split */
++ __BLK_TA_BOUNCE, /* bio was bounced */
++ __BLK_TA_REMAP, /* bio was remapped */
++};
++
++/*
++ * Trace actions in full. Additionally, read or write is masked
++ */
++#define BLK_TA_QUEUE (__BLK_TA_QUEUE | BLK_TC_ACT(BLK_TC_QUEUE))
++#define BLK_TA_BACKMERGE (__BLK_TA_BACKMERGE | BLK_TC_ACT(BLK_TC_QUEUE))
++#define BLK_TA_FRONTMERGE (__BLK_TA_FRONTMERGE | BLK_TC_ACT(BLK_TC_QUEUE))
++#define BLK_TA_GETRQ (__BLK_TA_GETRQ | BLK_TC_ACT(BLK_TC_QUEUE))
++#define BLK_TA_SLEEPRQ (__BLK_TA_SLEEPRQ | BLK_TC_ACT(BLK_TC_QUEUE))
++#define BLK_TA_REQUEUE (__BLK_TA_REQUEUE | BLK_TC_ACT(BLK_TC_REQUEUE))
++#define BLK_TA_ISSUE (__BLK_TA_ISSUE | BLK_TC_ACT(BLK_TC_ISSUE))
++#define BLK_TA_COMPLETE (__BLK_TA_COMPLETE| BLK_TC_ACT(BLK_TC_COMPLETE))
++#define BLK_TA_PLUG (__BLK_TA_PLUG | BLK_TC_ACT(BLK_TC_QUEUE))
++#define BLK_TA_UNPLUG_IO (__BLK_TA_UNPLUG_IO | BLK_TC_ACT(BLK_TC_QUEUE))
++#define BLK_TA_UNPLUG_TIMER (__BLK_TA_UNPLUG_TIMER | BLK_TC_ACT(BLK_TC_QUEUE))
++#define BLK_TA_INSERT (__BLK_TA_INSERT | BLK_TC_ACT(BLK_TC_QUEUE))
++#define BLK_TA_SPLIT (__BLK_TA_SPLIT)
++#define BLK_TA_BOUNCE (__BLK_TA_BOUNCE)
++#define BLK_TA_REMAP (__BLK_TA_REMAP | BLK_TC_ACT(BLK_TC_QUEUE))
++
++#define BLK_IO_TRACE_MAGIC 0x65617400
++#define BLK_IO_TRACE_VERSION 0x06
++
++/*
++ * The trace itself
++ */
++struct blk_io_trace {
++ u32 magic; /* MAGIC << 8 | version */
++ u32 sequence; /* event number */
++ u64 time; /* in microseconds */
++ u64 sector; /* disk offset */
++ u32 bytes; /* transfer length */
++ u32 action; /* what happened */
++ u32 pid; /* who did it */
++ u32 cpu; /* on what cpu did it happen */
++ u16 error; /* completion error */
++ u16 pdu_len; /* length of data after this trace */
++ u32 device; /* device number */
++ char comm[16]; /* task command name (TASK_COMM_LEN) */
++};
++
++/*
++ * The remap event
++ */
++struct blk_io_trace_remap {
++ u32 device;
++ u32 __pad;
++ u64 sector;
++};
++
++struct blk_trace {
++ struct dentry *dir;
++ struct rchan *rchan;
++ struct dentry *dropped_file;
++ atomic_t dropped;
++ unsigned long *sequence;
++ u32 dev;
++ u16 act_mask;
++ u64 start_lba;
++ u64 end_lba;
++ u32 pid;
++};
++
++/*
++ * User setup structure passed with BLKSTARTTRACE
++ */
++struct blk_user_trace_setup {
++ char name[BDEVNAME_SIZE]; /* output */
++ u16 act_mask; /* input */
++ u32 buf_size; /* input */
++ u32 buf_nr; /* input */
++ u64 start_lba;
++ u64 end_lba;
++ u32 pid;
++};
++
++#if defined(CONFIG_BLK_DEV_IO_TRACE)
++extern int blk_start_trace(struct block_device *, char __user *);
++extern int blk_stop_trace(struct block_device *);
++extern void blk_cleanup_trace(struct blk_trace *);
++extern void __blk_add_trace(struct blk_trace *, sector_t, int, int, u32, int, int, void *);
++
++static inline void blk_add_trace_rq(struct request_queue *q, struct request *rq,
++ u32 what)
++{
++ struct blk_trace *bt = q->blk_trace;
++ int rw = rq->flags & 0x07;
++
++ if (likely(!bt))
++ return;
++
++ 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 inline 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 inline void blk_add_trace_generic(struct request_queue *q,
++ struct bio *bio, int rw, u32 what)
++{
++ struct blk_trace *bt = q->blk_trace;
++
++ if (likely(!bt))
++ return;
++
++ if (bio)
++ blk_add_trace_bio(q, bio, what);
++ else
++ __blk_add_trace(bt, 0, 0, rw, what, 0, 0, NULL);
++}
++
++static inline void blk_add_trace_pdu_int(struct request_queue *q, u32 what,
++ struct bio *bio, unsigned int pdu)
++{
++ struct blk_trace *bt = q->blk_trace;
++ u64 rpdu = cpu_to_be64(pdu);
++
++ if (likely(!bt))
++ return;
++
++ if (bio)
++ __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, what, !bio_flagged(bio, BIO_UPTODATE), sizeof(rpdu), &rpdu);
++ else
++ __blk_add_trace(bt, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu);
++}
++
++static inline 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.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);
++}
++
++#else /* !CONFIG_BLK_DEV_IO_TRACE */
++#define blk_start_trace(bdev, arg) (-EINVAL)
++#define blk_stop_trace(bdev) (-EINVAL)
++#define blk_cleanup_trace(bt) do { } while (0)
++#define blk_add_trace_rq(q, rq, what) do { } while (0)
++#define blk_add_trace_bio(q, rq, what) do { } while (0)
++#define blk_add_trace_generic(q, rq, rw, what) do { } while (0)
++#define blk_add_trace_pdu_int(q, what, bio, pdu) do { } while (0)
++#define blk_add_trace_remap(q, bio, dev, f, t) do {} while (0)
++#endif /* CONFIG_BLK_DEV_IO_TRACE */
++
++#endif
+diff --git a/include/linux/compat_ioctl.h b/include/linux/compat_ioctl.h
+index 8fad50f..5bed09a 100644
+--- a/include/linux/compat_ioctl.h
++++ b/include/linux/compat_ioctl.h
+@@ -97,6 +97,8 @@ COMPATIBLE_IOCTL(BLKRRPART)
+ COMPATIBLE_IOCTL(BLKFLSBUF)
+ COMPATIBLE_IOCTL(BLKSECTSET)
+ COMPATIBLE_IOCTL(BLKSSZGET)
++COMPATIBLE_IOCTL(BLKSTARTTRACE)
++COMPATIBLE_IOCTL(BLKSTOPTRACE)
+ ULONG_IOCTL(BLKRASET)
+ ULONG_IOCTL(BLKFRASET)
+ /* RAID */
+diff --git a/include/linux/fs.h b/include/linux/fs.h
+index b77f260..5575284 100644
+--- a/include/linux/fs.h
++++ b/include/linux/fs.h
+@@ -196,6 +196,8 @@ extern int dir_notify_enable;
+ #define BLKBSZGET _IOR(0x12,112,size_t)
+ #define BLKBSZSET _IOW(0x12,113,size_t)
+ #define BLKGETSIZE64 _IOR(0x12,114,size_t) /* return device size in bytes (u64 *arg) */
++#define BLKSTARTTRACE _IOWR(0x12,115,struct blk_user_trace_setup)
++#define BLKSTOPTRACE _IO(0x12,116)
+
+ #define BMAP_IOCTL 1 /* obsolete - kept for compatibility */
+ #define FIBMAP _IO(0x00,1) /* bmap access */
+diff --git a/mm/highmem.c b/mm/highmem.c
+index ce2e7e8..d0ea1ee 100644
+--- a/mm/highmem.c
++++ b/mm/highmem.c
+@@ -26,6 +26,7 @@
+ #include <linux/init.h>
+ #include <linux/hash.h>
+ #include <linux/highmem.h>
++#include <linux/blktrace_api.h>
+ #include <asm/tlbflush.h>
+
+ static mempool_t *page_pool, *isa_page_pool;
+@@ -483,6 +484,8 @@ void blk_queue_bounce(request_queue_t *q
+ pool = isa_page_pool;
+ }
+
++ blk_add_trace_bio(q, *bio_orig, BLK_TA_BOUNCE);
++
+ /*
+ * slow path
+ */
projects / blktrace.git / commitdiff