tracing: Consolidate trace() functions

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>

diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h
index 67f528e..2109829 100644 (file)
--- a/include/linux/trace_events.h
+++ b/include/linux/trace_events.h
@@ -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;
 };

diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 99a0216..65b54d6 100644 (file)
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -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
@@ -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;
 }
@@ -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;
 }
@@ -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);
@@ -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;
@@ -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;
 }