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tracing: Consolidate trace() functions
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Move the checking, buffer reserve and buffer commit code in
synth_event_trace_start/end() into inline functions
__synth_event_trace_start/end() so they can also be used by
synth_event_trace() and synth_event_trace_array(), and then have all
those functions use them.

Also, change synth_event_trace_state.enabled to disabled so it only
needs to be set if the event is disabled, which is not normally the
case.

Link: http://lkml.kernel.org/r/b1f3108d0f450e58192955a300e31d0405ab4149.1581374549.git.zanussi@kernel.org

Signed-off-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Tom Zanussi authored and rostedt committed Feb 11, 2020
1 parent 0c62f6c commit 7276531
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Showing 2 changed files with 87 additions and 135 deletions.
2 changes: 1 addition & 1 deletion include/linux/trace_events.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -424,7 +424,7 @@ struct synth_event_trace_state {
struct synth_event *event;
unsigned int cur_field;
unsigned int n_u64;
bool enabled;
bool disabled;
bool add_next;
bool add_name;
};
Expand Down
220 changes: 86 additions & 134 deletions kernel/trace/trace_events_hist.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1791,6 +1791,60 @@ void synth_event_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen)
}
EXPORT_SYMBOL_GPL(synth_event_cmd_init);

static inline int
__synth_event_trace_start(struct trace_event_file *file,
struct synth_event_trace_state *trace_state)
{
int entry_size, fields_size = 0;
int ret = 0;

/*
* Normal event tracing doesn't get called at all unless the
* ENABLED bit is set (which attaches the probe thus allowing
* this code to be called, etc). Because this is called
* directly by the user, we don't have that but we still need
* to honor not logging when disabled. For the the iterated
* trace case, we save the enabed state upon start and just
* ignore the following data calls.
*/
if (!(file->flags & EVENT_FILE_FL_ENABLED) ||
trace_trigger_soft_disabled(file)) {
trace_state->disabled = true;
ret = -ENOENT;
goto out;
}

trace_state->event = file->event_call->data;

fields_size = trace_state->event->n_u64 * sizeof(u64);

/*
* Avoid ring buffer recursion detection, as this event
* is being performed within another event.
*/
trace_state->buffer = file->tr->array_buffer.buffer;
ring_buffer_nest_start(trace_state->buffer);

entry_size = sizeof(*trace_state->entry) + fields_size;
trace_state->entry = trace_event_buffer_reserve(&trace_state->fbuffer,
file,
entry_size);
if (!trace_state->entry) {
ring_buffer_nest_end(trace_state->buffer);
ret = -EINVAL;
}
out:
return ret;
}

static inline void
__synth_event_trace_end(struct synth_event_trace_state *trace_state)
{
trace_event_buffer_commit(&trace_state->fbuffer);

ring_buffer_nest_end(trace_state->buffer);
}

/**
* synth_event_trace - Trace a synthetic event
* @file: The trace_event_file representing the synthetic event
Expand All @@ -1812,69 +1866,38 @@ EXPORT_SYMBOL_GPL(synth_event_cmd_init);
*/
int synth_event_trace(struct trace_event_file *file, unsigned int n_vals, ...)
{
struct trace_event_buffer fbuffer;
struct synth_trace_event *entry;
struct trace_buffer *buffer;
struct synth_event *event;
struct synth_event_trace_state state;
unsigned int i, n_u64;
int fields_size = 0;
va_list args;
int ret = 0;

/*
* Normal event generation doesn't get called at all unless
* the ENABLED bit is set (which attaches the probe thus
* allowing this code to be called, etc). Because this is
* called directly by the user, we don't have that but we
* still need to honor not logging when disabled.
*/
if (!(file->flags & EVENT_FILE_FL_ENABLED) ||
trace_trigger_soft_disabled(file))
return 0;

event = file->event_call->data;

if (n_vals != event->n_fields)
return -EINVAL;

fields_size = event->n_u64 * sizeof(u64);

/*
* Avoid ring buffer recursion detection, as this event
* is being performed within another event.
*/
buffer = file->tr->array_buffer.buffer;
ring_buffer_nest_start(buffer);
int ret;

entry = trace_event_buffer_reserve(&fbuffer, file,
sizeof(*entry) + fields_size);
if (!entry) {
ret = -EINVAL;
goto out;
ret = __synth_event_trace_start(file, &state);
if (ret) {
if (ret == -ENOENT)
ret = 0; /* just disabled, not really an error */
return ret;
}

va_start(args, n_vals);
for (i = 0, n_u64 = 0; i < event->n_fields; i++) {
for (i = 0, n_u64 = 0; i < state.event->n_fields; i++) {
u64 val;

val = va_arg(args, u64);

if (event->fields[i]->is_string) {
if (state.event->fields[i]->is_string) {
char *str_val = (char *)(long)val;
char *str_field = (char *)&entry->fields[n_u64];
char *str_field = (char *)&state.entry->fields[n_u64];

strscpy(str_field, str_val, STR_VAR_LEN_MAX);
n_u64 += STR_VAR_LEN_MAX / sizeof(u64);
} else {
entry->fields[n_u64] = val;
state.entry->fields[n_u64] = val;
n_u64++;
}
}
va_end(args);

trace_event_buffer_commit(&fbuffer);
out:
ring_buffer_nest_end(buffer);
__synth_event_trace_end(&state);

return ret;
}
Expand All @@ -1901,62 +1924,31 @@ EXPORT_SYMBOL_GPL(synth_event_trace);
int synth_event_trace_array(struct trace_event_file *file, u64 *vals,
unsigned int n_vals)
{
struct trace_event_buffer fbuffer;
struct synth_trace_event *entry;
struct trace_buffer *buffer;
struct synth_event *event;
struct synth_event_trace_state state;
unsigned int i, n_u64;
int fields_size = 0;
int ret = 0;

/*
* Normal event generation doesn't get called at all unless
* the ENABLED bit is set (which attaches the probe thus
* allowing this code to be called, etc). Because this is
* called directly by the user, we don't have that but we
* still need to honor not logging when disabled.
*/
if (!(file->flags & EVENT_FILE_FL_ENABLED) ||
trace_trigger_soft_disabled(file))
return 0;

event = file->event_call->data;

if (n_vals != event->n_fields)
return -EINVAL;

fields_size = event->n_u64 * sizeof(u64);

/*
* Avoid ring buffer recursion detection, as this event
* is being performed within another event.
*/
buffer = file->tr->array_buffer.buffer;
ring_buffer_nest_start(buffer);
int ret;

entry = trace_event_buffer_reserve(&fbuffer, file,
sizeof(*entry) + fields_size);
if (!entry) {
ret = -EINVAL;
goto out;
ret = __synth_event_trace_start(file, &state);
if (ret) {
if (ret == -ENOENT)
ret = 0; /* just disabled, not really an error */
return ret;
}

for (i = 0, n_u64 = 0; i < event->n_fields; i++) {
if (event->fields[i]->is_string) {
for (i = 0, n_u64 = 0; i < state.event->n_fields; i++) {
if (state.event->fields[i]->is_string) {
char *str_val = (char *)(long)vals[i];
char *str_field = (char *)&entry->fields[n_u64];
char *str_field = (char *)&state.entry->fields[n_u64];

strscpy(str_field, str_val, STR_VAR_LEN_MAX);
n_u64 += STR_VAR_LEN_MAX / sizeof(u64);
} else {
entry->fields[n_u64] = vals[i];
state.entry->fields[n_u64] = vals[i];
n_u64++;
}
}

trace_event_buffer_commit(&fbuffer);
out:
ring_buffer_nest_end(buffer);
__synth_event_trace_end(&state);

return ret;
}
Expand Down Expand Up @@ -1993,55 +1985,17 @@ EXPORT_SYMBOL_GPL(synth_event_trace_array);
int synth_event_trace_start(struct trace_event_file *file,
struct synth_event_trace_state *trace_state)
{
struct synth_trace_event *entry;
int fields_size = 0;
int ret = 0;
int ret;

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

memset(trace_state, '\0', sizeof(*trace_state));

/*
* Normal event tracing doesn't get called at all unless the
* ENABLED bit is set (which attaches the probe thus allowing
* this code to be called, etc). Because this is called
* directly by the user, we don't have that but we still need
* to honor not logging when disabled. For the the iterated
* trace case, we save the enabed state upon start and just
* ignore the following data calls.
*/
if (!(file->flags & EVENT_FILE_FL_ENABLED) ||
trace_trigger_soft_disabled(file)) {
trace_state->enabled = false;
goto out;
}

trace_state->enabled = true;
ret = __synth_event_trace_start(file, trace_state);
if (ret == -ENOENT)
ret = 0; /* just disabled, not really an error */

trace_state->event = file->event_call->data;

fields_size = trace_state->event->n_u64 * sizeof(u64);

/*
* Avoid ring buffer recursion detection, as this event
* is being performed within another event.
*/
trace_state->buffer = file->tr->array_buffer.buffer;
ring_buffer_nest_start(trace_state->buffer);

entry = trace_event_buffer_reserve(&trace_state->fbuffer, file,
sizeof(*entry) + fields_size);
if (!entry) {
ring_buffer_nest_end(trace_state->buffer);
ret = -EINVAL;
goto out;
}

trace_state->entry = entry;
out:
return ret;
}
EXPORT_SYMBOL_GPL(synth_event_trace_start);
Expand Down Expand Up @@ -2074,7 +2028,7 @@ static int __synth_event_add_val(const char *field_name, u64 val,
trace_state->add_next = true;
}

if (!trace_state->enabled)
if (trace_state->disabled)
goto out;

event = trace_state->event;
Expand Down Expand Up @@ -2209,9 +2163,7 @@ int synth_event_trace_end(struct synth_event_trace_state *trace_state)
if (!trace_state)
return -EINVAL;

trace_event_buffer_commit(&trace_state->fbuffer);

ring_buffer_nest_end(trace_state->buffer);
__synth_event_trace_end(trace_state);

return 0;
}
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