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tracing: Move the trace_seq_* functions into its own trace_seq.c file
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The trace_seq_*() functions are a nice utility that allows users to manipulate
buffers with printf() like formats. It has its own trace_seq.h header in
include/linux and should be in its own file. Being tied with trace_output.c
is rather awkward.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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Steven Rostedt (Red Hat) committed Jul 1, 2014
1 parent 5c27c77 commit 1230627
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Showing 6 changed files with 306 additions and 295 deletions.
2 changes: 2 additions & 0 deletions include/linux/trace_seq.h
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Expand Up @@ -25,6 +25,8 @@ trace_seq_init(struct trace_seq *s)
s->full = 0;
}

#define MAX_MEMHEX_BYTES 8

/*
* Currently only defined when tracing is enabled.
*/
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1 change: 1 addition & 0 deletions kernel/trace/Makefile
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Expand Up @@ -28,6 +28,7 @@ obj-$(CONFIG_RING_BUFFER_BENCHMARK) += ring_buffer_benchmark.o

obj-$(CONFIG_TRACING) += trace.o
obj-$(CONFIG_TRACING) += trace_output.o
obj-$(CONFIG_TRACING) += trace_seq.o
obj-$(CONFIG_TRACING) += trace_stat.o
obj-$(CONFIG_TRACING) += trace_printk.o
obj-$(CONFIG_CONTEXT_SWITCH_TRACER) += trace_sched_switch.o
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24 changes: 0 additions & 24 deletions kernel/trace/trace.c
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Expand Up @@ -923,30 +923,6 @@ int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
return ret;
}

ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, size_t cnt)
{
int len;
int ret;

if (!cnt)
return 0;

if (s->len <= s->readpos)
return -EBUSY;

len = s->len - s->readpos;
if (cnt > len)
cnt = len;
ret = copy_to_user(ubuf, s->buffer + s->readpos, cnt);
if (ret == cnt)
return -EFAULT;

cnt -= ret;

s->readpos += cnt;
return cnt;
}

static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt)
{
int len;
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268 changes: 0 additions & 268 deletions kernel/trace/trace_output.c
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Original file line number Diff line number Diff line change
Expand Up @@ -20,23 +20,6 @@ static struct hlist_head event_hash[EVENT_HASHSIZE] __read_mostly;

static int next_event_type = __TRACE_LAST_TYPE + 1;

int trace_print_seq(struct seq_file *m, struct trace_seq *s)
{
int len = s->len >= PAGE_SIZE ? PAGE_SIZE - 1 : s->len;
int ret;

ret = seq_write(m, s->buffer, len);

/*
* Only reset this buffer if we successfully wrote to the
* seq_file buffer.
*/
if (!ret)
trace_seq_init(s);

return ret;
}

enum print_line_t trace_print_bputs_msg_only(struct trace_iterator *iter)
{
struct trace_seq *s = &iter->seq;
Expand Down Expand Up @@ -85,257 +68,6 @@ enum print_line_t trace_print_printk_msg_only(struct trace_iterator *iter)
return TRACE_TYPE_HANDLED;
}

/**
* trace_seq_printf - sequence printing of trace information
* @s: trace sequence descriptor
* @fmt: printf format string
*
* It returns 0 if the trace oversizes the buffer's free
* space, 1 otherwise.
*
* The tracer may use either sequence operations or its own
* copy to user routines. To simplify formating of a trace
* trace_seq_printf is used to store strings into a special
* buffer (@s). Then the output may be either used by
* the sequencer or pulled into another buffer.
*/
int
trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
{
int len = (PAGE_SIZE - 1) - s->len;
va_list ap;
int ret;

if (s->full || !len)
return 0;

va_start(ap, fmt);
ret = vsnprintf(s->buffer + s->len, len, fmt, ap);
va_end(ap);

/* If we can't write it all, don't bother writing anything */
if (ret >= len) {
s->full = 1;
return 0;
}

s->len += ret;

return 1;
}
EXPORT_SYMBOL_GPL(trace_seq_printf);

/**
* trace_seq_bitmask - put a list of longs as a bitmask print output
* @s: trace sequence descriptor
* @maskp: points to an array of unsigned longs that represent a bitmask
* @nmaskbits: The number of bits that are valid in @maskp
*
* It returns 0 if the trace oversizes the buffer's free
* space, 1 otherwise.
*
* Writes a ASCII representation of a bitmask string into @s.
*/
int
trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
int nmaskbits)
{
int len = (PAGE_SIZE - 1) - s->len;
int ret;

if (s->full || !len)
return 0;

ret = bitmap_scnprintf(s->buffer, len, maskp, nmaskbits);
s->len += ret;

return 1;
}
EXPORT_SYMBOL_GPL(trace_seq_bitmask);

/**
* trace_seq_vprintf - sequence printing of trace information
* @s: trace sequence descriptor
* @fmt: printf format string
*
* The tracer may use either sequence operations or its own
* copy to user routines. To simplify formating of a trace
* trace_seq_printf is used to store strings into a special
* buffer (@s). Then the output may be either used by
* the sequencer or pulled into another buffer.
*/
int
trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args)
{
int len = (PAGE_SIZE - 1) - s->len;
int ret;

if (s->full || !len)
return 0;

ret = vsnprintf(s->buffer + s->len, len, fmt, args);

/* If we can't write it all, don't bother writing anything */
if (ret >= len) {
s->full = 1;
return 0;
}

s->len += ret;

return len;
}
EXPORT_SYMBOL_GPL(trace_seq_vprintf);

int trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary)
{
int len = (PAGE_SIZE - 1) - s->len;
int ret;

if (s->full || !len)
return 0;

ret = bstr_printf(s->buffer + s->len, len, fmt, binary);

/* If we can't write it all, don't bother writing anything */
if (ret >= len) {
s->full = 1;
return 0;
}

s->len += ret;

return len;
}

/**
* trace_seq_puts - trace sequence printing of simple string
* @s: trace sequence descriptor
* @str: simple string to record
*
* The tracer may use either the sequence operations or its own
* copy to user routines. This function records a simple string
* into a special buffer (@s) for later retrieval by a sequencer
* or other mechanism.
*/
int trace_seq_puts(struct trace_seq *s, const char *str)
{
int len = strlen(str);

if (s->full)
return 0;

if (len > ((PAGE_SIZE - 1) - s->len)) {
s->full = 1;
return 0;
}

memcpy(s->buffer + s->len, str, len);
s->len += len;

return len;
}

int trace_seq_putc(struct trace_seq *s, unsigned char c)
{
if (s->full)
return 0;

if (s->len >= (PAGE_SIZE - 1)) {
s->full = 1;
return 0;
}

s->buffer[s->len++] = c;

return 1;
}
EXPORT_SYMBOL(trace_seq_putc);

int trace_seq_putmem(struct trace_seq *s, const void *mem, size_t len)
{
if (s->full)
return 0;

if (len > ((PAGE_SIZE - 1) - s->len)) {
s->full = 1;
return 0;
}

memcpy(s->buffer + s->len, mem, len);
s->len += len;

return len;
}

int trace_seq_putmem_hex(struct trace_seq *s, const void *mem, size_t len)
{
unsigned char hex[HEX_CHARS];
const unsigned char *data = mem;
int i, j;

if (s->full)
return 0;

#ifdef __BIG_ENDIAN
for (i = 0, j = 0; i < len; i++) {
#else
for (i = len-1, j = 0; i >= 0; i--) {
#endif
hex[j++] = hex_asc_hi(data[i]);
hex[j++] = hex_asc_lo(data[i]);
}
hex[j++] = ' ';

return trace_seq_putmem(s, hex, j);
}

void *trace_seq_reserve(struct trace_seq *s, size_t len)
{
void *ret;

if (s->full)
return NULL;

if (len > ((PAGE_SIZE - 1) - s->len)) {
s->full = 1;
return NULL;
}

ret = s->buffer + s->len;
s->len += len;

return ret;
}

int trace_seq_path(struct trace_seq *s, const struct path *path)
{
unsigned char *p;

if (s->full)
return 0;

if (s->len >= (PAGE_SIZE - 1)) {
s->full = 1;
return 0;
}

p = d_path(path, s->buffer + s->len, PAGE_SIZE - s->len);
if (!IS_ERR(p)) {
p = mangle_path(s->buffer + s->len, p, "\n");
if (p) {
s->len = p - s->buffer;
return 1;
}
} else {
s->buffer[s->len++] = '?';
return 1;
}

s->full = 1;
return 0;
}

const char *
ftrace_print_flags_seq(struct trace_seq *p, const char *delim,
unsigned long flags,
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3 changes: 0 additions & 3 deletions kernel/trace/trace_output.h
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Original file line number Diff line number Diff line change
Expand Up @@ -35,9 +35,6 @@ trace_print_lat_fmt(struct trace_seq *s, struct trace_entry *entry);
extern int __unregister_ftrace_event(struct trace_event *event);
extern struct rw_semaphore trace_event_sem;

#define MAX_MEMHEX_BYTES 8
#define HEX_CHARS (MAX_MEMHEX_BYTES*2 + 1)

#define SEQ_PUT_FIELD_RET(s, x) \
do { \
if (!trace_seq_putmem(s, &(x), sizeof(x))) \
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