perf ftrace: Show error message when fails to set ftrace files

It'd be better for debugging to show an error message when it fails to
setup ftrace for some reason.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: kernel-team@lge.com
Link: http://lkml.kernel.org/r/20170618142302.25390-1-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Namhyung Kim 2017-06-18 23:22:59 +09:00 committed by Arnaldo Carvalho de Melo
parent 106dacd86f
commit e7bd9ba20a

View file

@ -61,6 +61,7 @@ static int __write_tracing_file(const char *name, const char *val, bool append)
int fd, ret = -1;
ssize_t size = strlen(val);
int flags = O_WRONLY;
char errbuf[512];
file = get_tracing_file(name);
if (!file) {
@ -75,14 +76,16 @@ static int __write_tracing_file(const char *name, const char *val, bool append)
fd = open(file, flags);
if (fd < 0) {
pr_debug("cannot open tracing file: %s\n", name);
pr_debug("cannot open tracing file: %s: %s\n",
name, str_error_r(errno, errbuf, sizeof(errbuf)));
goto out;
}
if (write(fd, val, size) == size)
ret = 0;
else
pr_debug("write '%s' to tracing/%s failed\n", val, name);
pr_debug("write '%s' to tracing/%s failed: %s\n",
val, name, str_error_r(errno, errbuf, sizeof(errbuf)));
close(fd);
out: