tracing/filters: Refactor subsystem filter code

Change:
	for_each_pred
		for_each_subsystem
To:
	for_each_subsystem
		for_each_pred

This change also prepares for later patches.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <4AD69502.8060903@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

2 files changed, 45 insertions, 80 deletions

diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index acef8b4636f0..628614532d16 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -683,7 +683,6 @@ struct event_filter {
         int                     n_preds;
         struct filter_pred      **preds;
         char                    *filter_string;
-        bool                    no_reset;
 };
 
 struct event_subsystem {
diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index 92672016da28..9c4f9a0dae2b 100644
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -615,14 +615,7 @@ static int init_subsystem_preds(struct event_subsystem *system)
         return 0;
 }
 
-enum {
-        FILTER_DISABLE_ALL,
-        FILTER_INIT_NO_RESET,
-        FILTER_SKIP_NO_RESET,
-};
-
-static void filter_free_subsystem_preds(struct event_subsystem *system,
-                                        int flag)
+static void filter_free_subsystem_preds(struct event_subsystem *system)
 {
         struct ftrace_event_call *call;
 
@@ -633,14 +626,6 @@ static void filter_free_subsystem_preds(struct event_subsystem *system,
                 if (strcmp(call->system, system->name) != 0)
                         continue;
 
-                if (flag == FILTER_INIT_NO_RESET) {
-                        call->filter->no_reset = false;
-                        continue;
-                }
-
-                if (flag == FILTER_SKIP_NO_RESET && call->filter->no_reset)
-                        continue;
-
                 filter_disable_preds(call);
                 remove_filter_string(call->filter);
         }
@@ -817,44 +802,6 @@ add_pred_fn:
         return 0;
 }
 
-static int filter_add_subsystem_pred(struct filter_parse_state *ps,
-                                     struct event_subsystem *system,
-                                     struct filter_pred *pred,
-                                     char *filter_string,
-                                     bool dry_run)
-{
-        struct ftrace_event_call *call;
-        int err = 0;
-        bool fail = true;
-
-        list_for_each_entry(call, &ftrace_events, list) {
-
-                if (!call->define_fields)
-                        continue;
-
-                if (strcmp(call->system, system->name))
-                        continue;
-
-                if (call->filter->no_reset)
-                        continue;
-
-                err = filter_add_pred(ps, call, pred, dry_run);
-                if (err)
-                        call->filter->no_reset = true;
-                else
-                        fail = false;
-
-                if (!dry_run)
-                        replace_filter_string(call->filter, filter_string);
-        }
-
-        if (fail) {
-                parse_error(ps, FILT_ERR_BAD_SUBSYS_FILTER, 0);
-                return err;
-        }
-        return 0;
-}
-
 static void parse_init(struct filter_parse_state *ps,
                        struct filter_op *ops,
                        char *infix_string)
@@ -1209,8 +1156,7 @@ static int check_preds(struct filter_parse_state *ps)
         return 0;
 }
 
-static int replace_preds(struct event_subsystem *system,
-                         struct ftrace_event_call *call,
+static int replace_preds(struct ftrace_event_call *call,
                          struct filter_parse_state *ps,
                          char *filter_string,
                          bool dry_run)
@@ -1257,11 +1203,7 @@ static int replace_preds(struct event_subsystem *system,
 add_pred:
                 if (!pred)
                         return -ENOMEM;
-                if (call)
-                        err = filter_add_pred(ps, call, pred, false);
-                else
-                        err = filter_add_subsystem_pred(ps, system, pred,
-                                                filter_string, dry_run);
+                err = filter_add_pred(ps, call, pred, dry_run);
                 filter_free_pred(pred);
                 if (err)
                         return err;
@@ -1272,6 +1214,44 @@ add_pred:
         return 0;
 }
 
+static int replace_system_preds(struct event_subsystem *system,
+                                struct filter_parse_state *ps,
+                                char *filter_string)
+{
+        struct ftrace_event_call *call;
+        int err;
+        bool fail = true;
+
+        list_for_each_entry(call, &ftrace_events, list) {
+
+                if (!call->define_fields)
+                        continue;
+
+                if (strcmp(call->system, system->name) != 0)
+                        continue;
+
+                /* try to see if the filter can be applied */
+                err = replace_preds(call, ps, filter_string, true);
+                if (err)
+                        continue;
+
+                /* really apply the filter */
+                filter_disable_preds(call);
+                err = replace_preds(call, ps, filter_string, false);
+                if (err)
+                        filter_disable_preds(call);
+                else
+                        replace_filter_string(call->filter, filter_string);
+                fail = false;
+        }
+
+        if (fail) {
+                parse_error(ps, FILT_ERR_BAD_SUBSYS_FILTER, 0);
+                return err;
+        }
+        return 0;
+}
+
 int apply_event_filter(struct ftrace_event_call *call, char *filter_string)
 {
         int err;
@@ -1306,7 +1286,7 @@ int apply_event_filter(struct ftrace_event_call *call, char *filter_string)
                 goto out;
         }
 
-        err = replace_preds(NULL, call, ps, filter_string, false);
+        err = replace_preds(call, ps, filter_string, false);
         if (err)
                 append_filter_err(ps, call->filter);
 
@@ -1334,7 +1314,7 @@ int apply_subsystem_event_filter(struct event_subsystem *system,
                 goto out_unlock;
 
         if (!strcmp(strstrip(filter_string), "0")) {
-                filter_free_subsystem_preds(system, FILTER_DISABLE_ALL);
+                filter_free_subsystem_preds(system);
                 remove_filter_string(system->filter);
                 mutex_unlock(&event_mutex);
                 return 0;
@@ -1354,23 +1334,9 @@ int apply_subsystem_event_filter(struct event_subsystem *system,
                 goto out;
         }
 
-        filter_free_subsystem_preds(system, FILTER_INIT_NO_RESET);
-
-        /* try to see the filter can be applied to which events */
-        err = replace_preds(system, NULL, ps, filter_string, true);
-        if (err) {
-                append_filter_err(ps, system->filter);
-                goto out;
-        }
-
-        filter_free_subsystem_preds(system, FILTER_SKIP_NO_RESET);
-
-        /* really apply the filter to the events */
-        err = replace_preds(system, NULL, ps, filter_string, false);
-        if (err) {
+        err = replace_system_preds(system, ps, filter_string);
+        if (err)
                 append_filter_err(ps, system->filter);
-                filter_free_subsystem_preds(system, 2);
-        }
 
 out:
         filter_opstack_clear(ps);