diff options
| -rw-r--r-- | include/linux/trace_seq.h | 2 | ||||
| -rw-r--r-- | kernel/trace/trace_output.c | 32 |
2 files changed, 34 insertions, 0 deletions
diff --git a/include/linux/trace_seq.h b/include/linux/trace_seq.h index ba9627f00d3f..c68bccba2074 100644 --- a/include/linux/trace_seq.h +++ b/include/linux/trace_seq.h @@ -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); diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c index 425725c1622d..c05aff465dc9 100644 --- a/kernel/trace/trace_output.c +++ b/kernel/trace/trace_output.c @@ -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; |