![Jens Axboe](/assets/img/avatar_default.png)
Currently it uses a single static char array, but that risks being corrupted when multiple users issue message notes at the same time. Make the buffers dynamically allocated when the trace is setup and make them per-cpu instead. The default max message size of 1k is also very large, the interface is mainly for small text notes. So shrink it to 128 bytes. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
331 lines
9.5 KiB
C
331 lines
9.5 KiB
C
#ifndef BLKTRACE_H
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#define BLKTRACE_H
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#include <linux/blkdev.h>
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#include <linux/relay.h>
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/*
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* Trace categories
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*/
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enum blktrace_cat {
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BLK_TC_READ = 1 << 0, /* reads */
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BLK_TC_WRITE = 1 << 1, /* writes */
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BLK_TC_BARRIER = 1 << 2, /* barrier */
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BLK_TC_SYNC = 1 << 3, /* sync IO */
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BLK_TC_QUEUE = 1 << 4, /* queueing/merging */
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BLK_TC_REQUEUE = 1 << 5, /* requeueing */
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BLK_TC_ISSUE = 1 << 6, /* issue */
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BLK_TC_COMPLETE = 1 << 7, /* completions */
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BLK_TC_FS = 1 << 8, /* fs requests */
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BLK_TC_PC = 1 << 9, /* pc requests */
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BLK_TC_NOTIFY = 1 << 10, /* special message */
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BLK_TC_AHEAD = 1 << 11, /* readahead */
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BLK_TC_META = 1 << 12, /* metadata */
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BLK_TC_END = 1 << 15, /* only 16-bits, reminder */
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};
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#define BLK_TC_SHIFT (16)
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#define BLK_TC_ACT(act) ((act) << BLK_TC_SHIFT)
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/*
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* Basic trace actions
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*/
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enum blktrace_act {
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__BLK_TA_QUEUE = 1, /* queued */
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__BLK_TA_BACKMERGE, /* back merged to existing rq */
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__BLK_TA_FRONTMERGE, /* front merge to existing rq */
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__BLK_TA_GETRQ, /* allocated new request */
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__BLK_TA_SLEEPRQ, /* sleeping on rq allocation */
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__BLK_TA_REQUEUE, /* request requeued */
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__BLK_TA_ISSUE, /* sent to driver */
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__BLK_TA_COMPLETE, /* completed by driver */
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__BLK_TA_PLUG, /* queue was plugged */
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__BLK_TA_UNPLUG_IO, /* queue was unplugged by io */
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__BLK_TA_UNPLUG_TIMER, /* queue was unplugged by timer */
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__BLK_TA_INSERT, /* insert request */
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__BLK_TA_SPLIT, /* bio was split */
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__BLK_TA_BOUNCE, /* bio was bounced */
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__BLK_TA_REMAP, /* bio was remapped */
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};
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/*
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* Notify events.
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*/
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enum blktrace_notify {
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__BLK_TN_PROCESS = 0, /* establish pid/name mapping */
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__BLK_TN_TIMESTAMP, /* include system clock */
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__BLK_TN_MESSAGE, /* Character string message */
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};
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/*
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* Trace actions in full. Additionally, read or write is masked
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*/
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#define BLK_TA_QUEUE (__BLK_TA_QUEUE | BLK_TC_ACT(BLK_TC_QUEUE))
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#define BLK_TA_BACKMERGE (__BLK_TA_BACKMERGE | BLK_TC_ACT(BLK_TC_QUEUE))
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#define BLK_TA_FRONTMERGE (__BLK_TA_FRONTMERGE | BLK_TC_ACT(BLK_TC_QUEUE))
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#define BLK_TA_GETRQ (__BLK_TA_GETRQ | BLK_TC_ACT(BLK_TC_QUEUE))
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#define BLK_TA_SLEEPRQ (__BLK_TA_SLEEPRQ | BLK_TC_ACT(BLK_TC_QUEUE))
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#define BLK_TA_REQUEUE (__BLK_TA_REQUEUE | BLK_TC_ACT(BLK_TC_REQUEUE))
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#define BLK_TA_ISSUE (__BLK_TA_ISSUE | BLK_TC_ACT(BLK_TC_ISSUE))
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#define BLK_TA_COMPLETE (__BLK_TA_COMPLETE| BLK_TC_ACT(BLK_TC_COMPLETE))
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#define BLK_TA_PLUG (__BLK_TA_PLUG | BLK_TC_ACT(BLK_TC_QUEUE))
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#define BLK_TA_UNPLUG_IO (__BLK_TA_UNPLUG_IO | BLK_TC_ACT(BLK_TC_QUEUE))
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#define BLK_TA_UNPLUG_TIMER (__BLK_TA_UNPLUG_TIMER | BLK_TC_ACT(BLK_TC_QUEUE))
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#define BLK_TA_INSERT (__BLK_TA_INSERT | BLK_TC_ACT(BLK_TC_QUEUE))
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#define BLK_TA_SPLIT (__BLK_TA_SPLIT)
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#define BLK_TA_BOUNCE (__BLK_TA_BOUNCE)
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#define BLK_TA_REMAP (__BLK_TA_REMAP | BLK_TC_ACT(BLK_TC_QUEUE))
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#define BLK_TN_PROCESS (__BLK_TN_PROCESS | BLK_TC_ACT(BLK_TC_NOTIFY))
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#define BLK_TN_TIMESTAMP (__BLK_TN_TIMESTAMP | BLK_TC_ACT(BLK_TC_NOTIFY))
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#define BLK_TN_MESSAGE (__BLK_TN_MESSAGE | BLK_TC_ACT(BLK_TC_NOTIFY))
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#define BLK_IO_TRACE_MAGIC 0x65617400
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#define BLK_IO_TRACE_VERSION 0x07
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/*
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* The trace itself
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*/
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struct blk_io_trace {
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u32 magic; /* MAGIC << 8 | version */
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u32 sequence; /* event number */
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u64 time; /* in microseconds */
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u64 sector; /* disk offset */
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u32 bytes; /* transfer length */
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u32 action; /* what happened */
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u32 pid; /* who did it */
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u32 device; /* device number */
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u32 cpu; /* on what cpu did it happen */
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u16 error; /* completion error */
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u16 pdu_len; /* length of data after this trace */
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};
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/*
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* The remap event
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*/
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struct blk_io_trace_remap {
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__be32 device;
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__be32 device_from;
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__be64 sector;
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};
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enum {
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Blktrace_setup = 1,
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Blktrace_running,
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Blktrace_stopped,
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};
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struct blk_trace {
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int trace_state;
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struct rchan *rchan;
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unsigned long *sequence;
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unsigned char *msg_data;
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u16 act_mask;
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u64 start_lba;
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u64 end_lba;
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u32 pid;
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u32 dev;
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struct dentry *dir;
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struct dentry *dropped_file;
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atomic_t dropped;
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};
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/*
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* User setup structure passed with BLKTRACESTART
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*/
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struct blk_user_trace_setup {
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char name[BDEVNAME_SIZE]; /* output */
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u16 act_mask; /* input */
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u32 buf_size; /* input */
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u32 buf_nr; /* input */
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u64 start_lba;
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u64 end_lba;
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u32 pid;
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};
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#ifdef __KERNEL__
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#if defined(CONFIG_BLK_DEV_IO_TRACE)
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extern int blk_trace_ioctl(struct block_device *, unsigned, char __user *);
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extern void blk_trace_shutdown(struct request_queue *);
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extern void __blk_add_trace(struct blk_trace *, sector_t, int, int, u32, int, int, void *);
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extern int do_blk_trace_setup(struct request_queue *q,
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char *name, dev_t dev, struct blk_user_trace_setup *buts);
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extern void __trace_note_message(struct blk_trace *, const char *fmt, ...);
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/**
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* blk_add_trace_msg - Add a (simple) message to the blktrace stream
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* @q: queue the io is for
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* @fmt: format to print message in
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* args... Variable argument list for format
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*
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* Description:
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* Records a (simple) message onto the blktrace stream.
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*
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* NOTE: BLK_TN_MAX_MSG characters are output at most.
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* NOTE: Can not use 'static inline' due to presence of var args...
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*
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**/
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#define blk_add_trace_msg(q, fmt, ...) \
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do { \
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struct blk_trace *bt = (q)->blk_trace; \
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if (unlikely(bt)) \
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__trace_note_message(bt, fmt, ##__VA_ARGS__); \
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} while (0)
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#define BLK_TN_MAX_MSG 128
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/**
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* blk_add_trace_rq - Add a trace for a request oriented action
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* @q: queue the io is for
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* @rq: the source request
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* @what: the action
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*
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* Description:
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* Records an action against a request. Will log the bio offset + size.
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*
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**/
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static inline void blk_add_trace_rq(struct request_queue *q, struct request *rq,
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u32 what)
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{
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struct blk_trace *bt = q->blk_trace;
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int rw = rq->cmd_flags & 0x03;
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if (likely(!bt))
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return;
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if (blk_pc_request(rq)) {
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what |= BLK_TC_ACT(BLK_TC_PC);
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__blk_add_trace(bt, 0, rq->data_len, rw, what, rq->errors, sizeof(rq->cmd), rq->cmd);
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} else {
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what |= BLK_TC_ACT(BLK_TC_FS);
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__blk_add_trace(bt, rq->hard_sector, rq->hard_nr_sectors << 9, rw, what, rq->errors, 0, NULL);
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}
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}
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/**
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* blk_add_trace_bio - Add a trace for a bio oriented action
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* @q: queue the io is for
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* @bio: the source bio
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* @what: the action
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*
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* Description:
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* Records an action against a bio. Will log the bio offset + size.
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*
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**/
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static inline void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
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u32 what)
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{
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struct blk_trace *bt = q->blk_trace;
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if (likely(!bt))
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return;
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__blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, what, !bio_flagged(bio, BIO_UPTODATE), 0, NULL);
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}
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/**
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* blk_add_trace_generic - Add a trace for a generic action
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* @q: queue the io is for
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* @bio: the source bio
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* @rw: the data direction
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* @what: the action
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*
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* Description:
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* Records a simple trace
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*
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**/
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static inline void blk_add_trace_generic(struct request_queue *q,
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struct bio *bio, int rw, u32 what)
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{
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struct blk_trace *bt = q->blk_trace;
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if (likely(!bt))
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return;
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if (bio)
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blk_add_trace_bio(q, bio, what);
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else
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__blk_add_trace(bt, 0, 0, rw, what, 0, 0, NULL);
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}
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/**
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* blk_add_trace_pdu_int - Add a trace for a bio with an integer payload
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* @q: queue the io is for
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* @what: the action
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* @bio: the source bio
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* @pdu: the integer payload
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*
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* Description:
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* Adds a trace with some integer payload. This might be an unplug
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* option given as the action, with the depth at unplug time given
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* as the payload
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*
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**/
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static inline void blk_add_trace_pdu_int(struct request_queue *q, u32 what,
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struct bio *bio, unsigned int pdu)
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{
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struct blk_trace *bt = q->blk_trace;
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__be64 rpdu = cpu_to_be64(pdu);
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if (likely(!bt))
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return;
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if (bio)
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__blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, what, !bio_flagged(bio, BIO_UPTODATE), sizeof(rpdu), &rpdu);
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else
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__blk_add_trace(bt, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu);
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}
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/**
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* blk_add_trace_remap - Add a trace for a remap operation
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* @q: queue the io is for
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* @bio: the source bio
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* @dev: target device
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* @from: source sector
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* @to: target sector
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*
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* Description:
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* Device mapper or raid target sometimes need to split a bio because
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* it spans a stripe (or similar). Add a trace for that action.
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*
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**/
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static inline void blk_add_trace_remap(struct request_queue *q, struct bio *bio,
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dev_t dev, sector_t from, sector_t to)
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{
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struct blk_trace *bt = q->blk_trace;
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struct blk_io_trace_remap r;
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if (likely(!bt))
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return;
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r.device = cpu_to_be32(dev);
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r.device_from = cpu_to_be32(bio->bi_bdev->bd_dev);
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r.sector = cpu_to_be64(to);
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__blk_add_trace(bt, from, bio->bi_size, bio->bi_rw, BLK_TA_REMAP, !bio_flagged(bio, BIO_UPTODATE), sizeof(r), &r);
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}
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extern int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
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char __user *arg);
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extern int blk_trace_startstop(struct request_queue *q, int start);
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extern int blk_trace_remove(struct request_queue *q);
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#else /* !CONFIG_BLK_DEV_IO_TRACE */
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#define blk_trace_ioctl(bdev, cmd, arg) (-ENOTTY)
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#define blk_trace_shutdown(q) do { } while (0)
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#define blk_add_trace_rq(q, rq, what) do { } while (0)
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#define blk_add_trace_bio(q, rq, what) do { } while (0)
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#define blk_add_trace_generic(q, rq, rw, what) do { } while (0)
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#define blk_add_trace_pdu_int(q, what, bio, pdu) do { } while (0)
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#define blk_add_trace_remap(q, bio, dev, f, t) do {} while (0)
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#define do_blk_trace_setup(q, name, dev, buts) (-ENOTTY)
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#define blk_trace_setup(q, name, dev, arg) (-ENOTTY)
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#define blk_trace_startstop(q, start) (-ENOTTY)
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#define blk_trace_remove(q) (-ENOTTY)
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#define blk_add_trace_msg(q, fmt, ...) do { } while (0)
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#endif /* CONFIG_BLK_DEV_IO_TRACE */
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#endif /* __KERNEL__ */
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#endif
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