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Commit 725c624a authored by Steven Rostedt's avatar Steven Rostedt Committed by Steven Rostedt
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tracing: add trace_seq_vprint interface 



The code to update the print formats for events requires a vprintf
format in the trace_seq. This patch adds that interface.

Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent 6556d1df

include/linux/trace_seq.h

+2 −0
Original line number Diff line number Diff line
@@ -27,6 +27,8 @@ trace_seq_init(struct trace_seq *s) 
#ifdef CONFIG_TRACING

extern int trace_seq_printf(struct trace_seq *s, const char *fmt, ...)

	__attribute__ ((format (printf, 2, 3)));

extern int trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args)

	__attribute__ ((format (printf, 2, 0)));

extern int

trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary);

extern void trace_print_seq(struct seq_file *m, struct trace_seq *s);

kernel/trace/trace_output.c

+32 −0
Original line number Diff line number Diff line
@@ -100,6 +100,38 @@ trace_seq_printf(struct trace_seq *s, const char *fmt, ...) 
}

EXPORT_SYMBOL_GPL(trace_seq_printf);



/**

 * 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 (!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)

		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;