tracing: make the set_event and available_events subsystem aware

This patch makes the event files, set_event and available_events
aware of the subsystem.

Now you can enable an entire subsystem with:

  echo 'irq:*' > set_event

Note: the '*' is not needed.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>

1 files changed, 40 insertions, 3 deletions

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 19332200c457..b811eb343522 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -12,6 +12,8 @@
 
 #include "trace_events.h"
 
+#define TRACE_SYSTEM "TRACE_SYSTEM"
+
 #define events_for_each(event)                                          \
         for (event = __start_ftrace_events;                             \
              (unsigned long)event < (unsigned long)__stop_ftrace_events; \
@@ -45,14 +47,47 @@ static void ftrace_clear_events(void)
 static int ftrace_set_clr_event(char *buf, int set)
 {
         struct ftrace_event_call *call = __start_ftrace_events;
+        char *event = NULL, *sub = NULL, *match;
+        int ret = -EINVAL;
+
+        /*
+         * The buf format can be <subsystem>:<event-name>
+         *  *:<event-name> means any event by that name.
+         *  :<event-name> is the same.
+         *
+         *  <subsystem>:* means all events in that subsystem
+         *  <subsystem>: means the same.
+         *
+         *  <name> (no ':') means all events in a subsystem with
+         *  the name <name> or any event that matches <name>
+         */
+
+        match = strsep(&buf, ":");
+        if (buf) {
+                sub = match;
+                event = buf;
+                match = NULL;
 
+                if (!strlen(sub) || strcmp(sub, "*") == 0)
+                        sub = NULL;
+                if (!strlen(event) || strcmp(event, "*") == 0)
+                        event = NULL;
+        }
 
         events_for_each(call) {
 
                 if (!call->name)
                         continue;
 
-                if (strcmp(buf, call->name) != 0)
+                if (match &&
+                    strcmp(match, call->name) != 0 &&
+                    strcmp(match, call->system) != 0)
+                        continue;
+
+                if (sub && strcmp(sub, call->system) != 0)
+                        continue;
+
+                if (event && strcmp(event, call->name) != 0)
                         continue;
 
                 if (set) {
@@ -68,9 +103,9 @@ static int ftrace_set_clr_event(char *buf, int set)
                         call->enabled = 0;
                         call->unregfunc();
                 }
-                return 0;
+                ret = 0;
         }
-        return -EINVAL;
+        return ret;
 }
 
 /* 128 should be much more than enough */
@@ -200,6 +235,8 @@ static int t_show(struct seq_file *m, void *v)
 {
         struct ftrace_event_call *call = v;
 
+        if (strcmp(call->system, TRACE_SYSTEM) != 0)
+                seq_printf(m, "%s:", call->system);
         seq_printf(m, "%s\n", call->name);
 
         return 0;