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>

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 19332200c457409040f787c0df7e7ed06ead92c6..b811eb343522c680835550dc2463926efde7cf2b 100644 (file)
--- 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;