Re: [PATCH 1/4] tracing: Consolidate some synth_event_trace code

From: Tom Zanussi
Date: Fri Jan 31 2020 - 18:00:42 EST


On Fri, 2020-01-31 at 17:43 -0500, Steven Rostedt wrote:
> On Fri, 31 Jan 2020 15:55:31 -0600
> Tom Zanussi <zanussi@xxxxxxxxxx> wrote:
>
> > +++ b/kernel/trace/trace_events_hist.c
> > @@ -2053,24 +2053,72 @@ int synth_event_trace_start(struct
> > trace_event_file *file,
> > }
> > EXPORT_SYMBOL_GPL(synth_event_trace_start);
> >
> > -static int save_synth_val(struct synth_field *field, u64 val,
> > +int __synth_event_add_val(const char *field_name, u64 val,
>
> Hmm, shouldn't __synth_event_add_val() still be static?
>
> -- Steve
>
> > struct synth_event_trace_state
> > *trace_state)
> > {
> > - struct synth_trace_event *entry = trace_state->entry;
> > + struct synth_field *field = NULL;
> > + struct synth_trace_event *entry;
> > + struct synth_event *event;
> > + int i, ret = 0;
> > +

Here's the patch with __synth_event_add_val() made static. Let me know
if you want me to just do a v2 of this series..

Thanks,

Tom

[PATCH] tracing: Consolidate some synth_event_trace code

The synth_event trace code contains some almost identical functions
and some small functions that are called only once - consolidate the
common code into single functions and fold in the small functions to
simplify the code overall.

Signed-off-by: Tom Zanussi <zanussi@xxxxxxxxxx>
---
kernel/trace/trace_events_hist.c | 141 ++++++++++++++++-----------------------
1 file changed, 57 insertions(+), 84 deletions(-)

diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 5b4e04780411..42058a1b5146 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -2053,24 +2053,72 @@ int synth_event_trace_start(struct trace_event_file *file,
}
EXPORT_SYMBOL_GPL(synth_event_trace_start);

-static int save_synth_val(struct synth_field *field, u64 val,
- struct synth_event_trace_state *trace_state)
+static int __synth_event_add_val(const char *field_name, u64 val,
+ struct synth_event_trace_state *trace_state)
{
- struct synth_trace_event *entry = trace_state->entry;
+ struct synth_field *field = NULL;
+ struct synth_trace_event *entry;
+ struct synth_event *event;
+ int i, ret = 0;
+
+ if (!trace_state) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ /* can't mix add_next_synth_val() with add_synth_val() */
+ if (field_name) {
+ if (trace_state->add_next) {
+ ret = -EINVAL;
+ goto out;
+ }
+ trace_state->add_name = true;
+ } else {
+ if (trace_state->add_name) {
+ ret = -EINVAL;
+ goto out;
+ }
+ trace_state->add_next = true;
+ }
+
+ if (!trace_state->enabled)
+ goto out;
+
+ event = trace_state->event;
+ if (trace_state->add_name) {
+ for (i = 0; i < event->n_fields; i++) {
+ field = event->fields[i];
+ if (strcmp(field->name, field_name) == 0)
+ break;
+ }
+ if (!field) {
+ ret = -EINVAL;
+ goto out;
+ }
+ } else {
+ if (trace_state->cur_field >= event->n_fields) {
+ ret = -EINVAL;
+ goto out;
+ }
+ field = event->fields[trace_state->cur_field++];
+ }

+ entry = trace_state->entry;
if (field->is_string) {
char *str_val = (char *)(long)val;
char *str_field;

- if (!str_val)
- return -EINVAL;
+ if (!str_val) {
+ ret = -EINVAL;
+ goto out;
+ }

str_field = (char *)&entry->fields[field->offset];
strscpy(str_field, str_val, STR_VAR_LEN_MAX);
} else
entry->fields[field->offset] = val;
-
- return 0;
+ out:
+ return ret;
}

/**
@@ -2104,54 +2152,10 @@ static int save_synth_val(struct synth_field *field, u64 val,
int synth_event_add_next_val(u64 val,
struct synth_event_trace_state *trace_state)
{
- struct synth_field *field;
- struct synth_event *event;
- int ret = 0;
-
- if (!trace_state) {
- ret = -EINVAL;
- goto out;
- }
-
- /* can't mix add_next_synth_val() with add_synth_val() */
- if (trace_state->add_name) {
- ret = -EINVAL;
- goto out;
- }
- trace_state->add_next = true;
-
- if (!trace_state->enabled)
- goto out;
-
- event = trace_state->event;
-
- if (trace_state->cur_field >= event->n_fields) {
- ret = -EINVAL;
- goto out;
- }
-
- field = event->fields[trace_state->cur_field++];
- ret = save_synth_val(field, val, trace_state);
- out:
- return ret;
+ return __synth_event_add_val(NULL, val, trace_state);
}
EXPORT_SYMBOL_GPL(synth_event_add_next_val);

-static struct synth_field *find_synth_field(struct synth_event *event,
- const char *field_name)
-{
- struct synth_field *field = NULL;
- unsigned int i;
-
- for (i = 0; i < event->n_fields; i++) {
- field = event->fields[i];
- if (strcmp(field->name, field_name) == 0)
- return field;
- }
-
- return NULL;
-}
-
/**
* synth_event_add_val - Add a named field's value to an open synth trace
* @field_name: The name of the synthetic event field value to set
@@ -2183,38 +2187,7 @@ static struct synth_field *find_synth_field(struct synth_event *event,
int synth_event_add_val(const char *field_name, u64 val,
struct synth_event_trace_state *trace_state)
{
- struct synth_trace_event *entry;
- struct synth_event *event;
- struct synth_field *field;
- int ret = 0;
-
- if (!trace_state) {
- ret = -EINVAL;
- goto out;
- }
-
- /* can't mix add_next_synth_val() with add_synth_val() */
- if (trace_state->add_next) {
- ret = -EINVAL;
- goto out;
- }
- trace_state->add_name = true;
-
- if (!trace_state->enabled)
- goto out;
-
- event = trace_state->event;
- entry = trace_state->entry;
-
- field = find_synth_field(event, field_name);
- if (!field) {
- ret = -EINVAL;
- goto out;
- }
-
- ret = save_synth_val(field, val, trace_state);
- out:
- return ret;
+ return __synth_event_add_val(field_name, val, trace_state);
}
EXPORT_SYMBOL_GPL(synth_event_add_val);

--
2.14.1