[PATCH 2/3] perf/probe: Cleanup synthesize_probe_trace_command

From: Masami Hiramatsu
Date: Fri Jun 04 2021 - 12:28:40 EST


Cleanup the synthesize_probe_trace_command() to simplify
code path.

Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
---
tools/perf/util/probe-event.c | 86 +++++++++++++++++++++++------------------
1 file changed, 49 insertions(+), 37 deletions(-)

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index a6e121afb651..505c0702dbe2 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -2127,19 +2127,55 @@ static int synthesize_probe_trace_arg(struct probe_trace_arg *arg,
}

static int
-synthesize_uprobe_trace_def(struct probe_trace_event *tev, struct strbuf *buf)
+synthesize_probe_trace_args(struct probe_trace_event *tev, struct strbuf *buf)
+{
+ int i, ret = 0;
+
+ for (i = 0; i < tev->nargs && ret >= 0; i++)
+ ret = synthesize_probe_trace_arg(&tev->args[i], buf);
+
+ return ret;
+}
+
+static int
+synthesize_uprobe_trace_def(struct probe_trace_point *tp, struct strbuf *buf)
{
- struct probe_trace_point *tp = &tev->point;
int err;

+ /* Uprobes must have tp->module */
+ if (!tp->module)
+ return -EINVAL;
+ /*
+ * If tp->address == 0, then this point must be a
+ * absolute address uprobe.
+ * try_to_find_absolute_address() should have made
+ * tp->symbol to "0x0".
+ */
+ if (!tp->address && (!tp->symbol || strcmp(tp->symbol, "0x0")))
+ return -EINVAL;
+
+ /* Use the tp->address for uprobes */
err = strbuf_addf(buf, "%s:0x%lx", tp->module, tp->address);

if (err >= 0 && tp->ref_ctr_offset) {
if (!uprobe_ref_ctr_is_supported())
- return -1;
+ return -EINVAL;
err = strbuf_addf(buf, "(0x%lx)", tp->ref_ctr_offset);
}
- return err >= 0 ? 0 : -1;
+ return err >= 0 ? 0 : err;
+}
+
+static int
+synthesize_kprobe_trace_def(struct probe_trace_point *tp, struct strbuf *buf)
+{
+ if (!strncmp(tp->symbol, "0x", 2)) {
+ /* Absolute address. See try_to_find_absolute_address() */
+ return strbuf_addf(buf, "%s%s0x%lx", tp->module ?: "",
+ tp->module ? ":" : "", tp->address);
+ } else {
+ return strbuf_addf(buf, "%s%s%s+%lu", tp->module ?: "",
+ tp->module ? ":" : "", tp->symbol, tp->offset);
+ }
}

char *synthesize_probe_trace_command(struct probe_trace_event *tev)
@@ -2147,11 +2183,7 @@ char *synthesize_probe_trace_command(struct probe_trace_event *tev)
struct probe_trace_point *tp = &tev->point;
struct strbuf buf;
char *ret = NULL;
- int i, err;
-
- /* Uprobes must have tp->module */
- if (tev->uprobes && !tp->module)
- return NULL;
+ int err;

if (strbuf_init(&buf, 32) < 0)
return NULL;
@@ -2159,37 +2191,17 @@ char *synthesize_probe_trace_command(struct probe_trace_event *tev)
if (strbuf_addf(&buf, "%c:%s/%s ", tp->retprobe ? 'r' : 'p',
tev->group, tev->event) < 0)
goto error;
- /*
- * If tp->address == 0, then this point must be a
- * absolute address uprobe.
- * try_to_find_absolute_address() should have made
- * tp->symbol to "0x0".
- */
- if (tev->uprobes && !tp->address) {
- if (!tp->symbol || strcmp(tp->symbol, "0x0"))
- goto error;
- }

- /* Use the tp->address for uprobes */
- if (tev->uprobes) {
- err = synthesize_uprobe_trace_def(tev, &buf);
- } else if (!strncmp(tp->symbol, "0x", 2)) {
- /* Absolute address. See try_to_find_absolute_address() */
- err = strbuf_addf(&buf, "%s%s0x%lx", tp->module ?: "",
- tp->module ? ":" : "", tp->address);
- } else {
- err = strbuf_addf(&buf, "%s%s%s+%lu", tp->module ?: "",
- tp->module ? ":" : "", tp->symbol, tp->offset);
- }
-
- if (err)
- goto error;
+ if (tev->uprobes)
+ err = synthesize_uprobe_trace_def(tp, &buf);
+ else
+ err = synthesize_kprobe_trace_def(tp, &buf);

- for (i = 0; i < tev->nargs; i++)
- if (synthesize_probe_trace_arg(&tev->args[i], &buf) < 0)
- goto error;
+ if (err >= 0)
+ err = synthesize_probe_trace_args(tev, &buf);

- ret = strbuf_detach(&buf, NULL);
+ if (err >= 0)
+ ret = strbuf_detach(&buf, NULL);
error:
strbuf_release(&buf);
return ret;