kernel/include/linux/blktrace_api.h

#ifndef BLKTRACE_H
#define BLKTRACE_H

#include <linux/types.h>
#ifdef __KERNEL__
#include <linux/blkdev.h>
#include <linux/relay.h>
#include <linux/compat.h>
#endif

/*
 * 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,	/* sync IO */
	BLK_TC_SYNCIO	= BLK_TC_SYNC,
	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_NOTIFY	= 1 << 10,	/* special message */
	BLK_TC_AHEAD	= 1 << 11,	/* readahead */
	BLK_TC_META	= 1 << 12,	/* metadata */
	BLK_TC_DISCARD	= 1 << 13,	/* discard requests */
	BLK_TC_DRV_DATA	= 1 << 14,	/* binary per-driver data */

	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 */
	__BLK_TA_ABORT,			/* request aborted */
	__BLK_TA_DRV_DATA,		/* driver-specific binary data */
};

/*
 * Notify events.
 */
enum blktrace_notify {
	__BLK_TN_PROCESS = 0,		/* establish pid/name mapping */
	__BLK_TN_TIMESTAMP,		/* include system clock */
	__BLK_TN_MESSAGE,		/* Character string message */
};


/*
 * 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_TA_ABORT		(__BLK_TA_ABORT | BLK_TC_ACT(BLK_TC_QUEUE))
#define BLK_TA_DRV_DATA	(__BLK_TA_DRV_DATA | BLK_TC_ACT(BLK_TC_DRV_DATA))

#define BLK_TN_PROCESS		(__BLK_TN_PROCESS | BLK_TC_ACT(BLK_TC_NOTIFY))
#define BLK_TN_TIMESTAMP	(__BLK_TN_TIMESTAMP | BLK_TC_ACT(BLK_TC_NOTIFY))
#define BLK_TN_MESSAGE		(__BLK_TN_MESSAGE | BLK_TC_ACT(BLK_TC_NOTIFY))

#define BLK_IO_TRACE_MAGIC	0x65617400
#define BLK_IO_TRACE_VERSION	0x07

/*
 * 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 device;		/* device number */
	__u32 cpu;		/* on what cpu did it happen */
	__u16 error;		/* completion error */
	__u16 pdu_len;		/* length of data after this trace */
};

/*
 * The remap event
 */
struct blk_io_trace_remap {
	__be32 device_from;
	__be32 device_to;
	__be64 sector_from;
};

enum {
	Blktrace_setup = 1,
	Blktrace_running,
	Blktrace_stopped,
};

#define BLKTRACE_BDEV_SIZE	32

/*
 * User setup structure passed with BLKTRACESTART
 */
struct blk_user_trace_setup {
	char name[BLKTRACE_BDEV_SIZE];	/* output */
	__u16 act_mask;			/* input */
	__u32 buf_size;			/* input */
	__u32 buf_nr;			/* input */
	__u64 start_lba;
	__u64 end_lba;
	__u32 pid;
};

#ifdef __KERNEL__
#if defined(CONFIG_BLK_DEV_IO_TRACE)

#include <linux/sysfs.h>

struct blk_trace {
	int trace_state;
	struct rchan *rchan;
	unsigned long __percpu *sequence;
	unsigned char __percpu *msg_data;
	u16 act_mask;
	u64 start_lba;
	u64 end_lba;
	u32 pid;
	u32 dev;
	struct dentry *dir;
	struct dentry *dropped_file;
	struct dentry *msg_file;
	atomic_t dropped;
};

extern int blk_trace_ioctl(struct block_device *, unsigned, char __user *);
extern void blk_trace_shutdown(struct request_queue *);
extern int do_blk_trace_setup(struct request_queue *q, char *name,
			      dev_t dev, struct block_device *bdev,
			      struct blk_user_trace_setup *buts);
extern __attribute__((format(printf, 2, 3)))
void __trace_note_message(struct blk_trace *, const char *fmt, ...);

/**
 * blk_add_trace_msg - Add a (simple) message to the blktrace stream
 * @q:		queue the io is for
 * @fmt:	format to print message in
 * args...	Variable argument list for format
 *
 * Description:
 *     Records a (simple) message onto the blktrace stream.
 *
 *     NOTE: BLK_TN_MAX_MSG characters are output at most.
 *     NOTE: Can not use 'static inline' due to presence of var args...
 *
 **/
#define blk_add_trace_msg(q, fmt, ...)					\
	do {								\
		struct blk_trace *bt = (q)->blk_trace;			\
		if (unlikely(bt))					\
			__trace_note_message(bt, fmt, ##__VA_ARGS__);	\
	} while (0)
#define BLK_TN_MAX_MSG		128

extern void blk_add_driver_data(struct request_queue *q, struct request *rq,
				void *data, size_t len);
extern int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
			   struct block_device *bdev,
			   char __user *arg);
extern int blk_trace_startstop(struct request_queue *q, int start);
extern int blk_trace_remove(struct request_queue *q);
extern void blk_trace_remove_sysfs(struct device *dev);
extern int blk_trace_init_sysfs(struct device *dev);

extern struct attribute_group blk_trace_attr_group;

#else /* !CONFIG_BLK_DEV_IO_TRACE */
# define blk_trace_ioctl(bdev, cmd, arg)		(-ENOTTY)
# define blk_trace_shutdown(q)				do { } while (0)
# define do_blk_trace_setup(q, name, dev, bdev, buts)	(-ENOTTY)
# define blk_add_driver_data(q, rq, data, len)		do {} while (0)
# define blk_trace_setup(q, name, dev, bdev, arg)	(-ENOTTY)
# define blk_trace_startstop(q, start)			(-ENOTTY)
# define blk_trace_remove(q)				(-ENOTTY)
# define blk_add_trace_msg(q, fmt, ...)			do { } while (0)
# define blk_trace_remove_sysfs(dev)			do { } while (0)
static inline int blk_trace_init_sysfs(struct device *dev)
{
	return 0;
}

#endif /* CONFIG_BLK_DEV_IO_TRACE */

#ifdef CONFIG_COMPAT

struct compat_blk_user_trace_setup {
	char name[32];
	u16 act_mask;
	u32 buf_size;
	u32 buf_nr;
	compat_u64 start_lba;
	compat_u64 end_lba;
	u32 pid;
};
#define BLKTRACESETUP32 _IOWR(0x12, 115, struct compat_blk_user_trace_setup)

#endif

#if defined(CONFIG_EVENT_TRACING) && defined(CONFIG_BLOCK)

static inline int blk_cmd_buf_len(struct request *rq)
{
	return (rq->cmd_type == REQ_TYPE_BLOCK_PC) ? rq->cmd_len * 3 : 1;
}

extern void blk_dump_cmd(char *buf, struct request *rq);
extern void blk_fill_rwbs(char *rwbs, u32 rw, int bytes);

#endif /* CONFIG_EVENT_TRACING && CONFIG_BLOCK */

#endif /* __KERNEL__ */
#endif