tracing/filters: use ring_buffer_discard_commit() in filter_check_discard()

This patch changes filter_check_discard() to make use of the new
ring_buffer_discard_commit() function and modifies the current users to
call the old commit function in the non-discard case.

It also introduces a version of filter_check_discard() that uses the
global trace buffer (filter_current_check_discard()) for those cases.

v2 changes:

- fix compile error noticed by Ingo Molnar

Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: fweisbec@gmail.com
LKML-Reference: <1239178554.10295.36.camel@tropicana>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

7 files changed, 48 insertions, 43 deletions

diff --git a/kernel/trace/kmemtrace.c b/kernel/trace/kmemtrace.c
index 9419ad10541b..86cdf671d7e2 100644
--- a/kernel/trace/kmemtrace.c
+++ b/kernel/trace/kmemtrace.c
@@ -63,9 +63,8 @@ static inline void kmemtrace_alloc(enum kmemtrace_type_id type_id,
         entry->gfp_flags        = gfp_flags;
         entry->node             = node;
 
-        filter_check_discard(call, entry, event);
-
-        ring_buffer_unlock_commit(tr->buffer, event);
+        if (!filter_check_discard(call, entry, tr->buffer, event))
+                ring_buffer_unlock_commit(tr->buffer, event);
 
         trace_wake_up();
 }
@@ -90,9 +89,8 @@ static inline void kmemtrace_free(enum kmemtrace_type_id type_id,
         entry->call_site        = call_site;
         entry->ptr              = ptr;
 
-        filter_check_discard(call, entry, event);
-
-        ring_buffer_unlock_commit(tr->buffer, event);
+        if (!filter_check_discard(call, entry, tr->buffer, event))
+                ring_buffer_unlock_commit(tr->buffer, event);
 
         trace_wake_up();
 }
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index d880ab2772ce..c0047fcf7076 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -171,6 +171,12 @@ static struct trace_array	global_trace;
 
 static DEFINE_PER_CPU(struct trace_array_cpu, global_trace_cpu);
 
+int filter_current_check_discard(struct ftrace_event_call *call, void *rec,
+                                 struct ring_buffer_event *event)
+{
+        return filter_check_discard(call, rec, global_trace.buffer, event);
+}
+
 cycle_t ftrace_now(int cpu)
 {
         u64 ts;
@@ -919,9 +925,8 @@ trace_function(struct trace_array *tr,
         entry->ip                       = ip;
         entry->parent_ip                = parent_ip;
 
-        filter_check_discard(call, entry, event);
-
-        ring_buffer_unlock_commit(tr->buffer, event);
+        if (!filter_check_discard(call, entry, tr->buffer, event))
+                ring_buffer_unlock_commit(tr->buffer, event);
 }
 
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
@@ -943,8 +948,8 @@ static int __trace_graph_entry(struct trace_array *tr,
                 return 0;
         entry   = ring_buffer_event_data(event);
         entry->graph_ent                        = *trace;
-        filter_check_discard(call, entry, event);
-        ring_buffer_unlock_commit(global_trace.buffer, event);
+        if (!filter_current_check_discard(call, entry, event))
+                ring_buffer_unlock_commit(global_trace.buffer, event);
 
         return 1;
 }
@@ -967,8 +972,8 @@ static void __trace_graph_return(struct trace_array *tr,
                 return;
         entry   = ring_buffer_event_data(event);
         entry->ret                              = *trace;
-        filter_check_discard(call, entry, event);
-        ring_buffer_unlock_commit(global_trace.buffer, event);
+        if (!filter_current_check_discard(call, entry, event))
+                ring_buffer_unlock_commit(global_trace.buffer, event);
 }
 #endif
 
@@ -1004,8 +1009,8 @@ static void __ftrace_trace_stack(struct trace_array *tr,
         trace.entries           = entry->caller;
 
         save_stack_trace(&trace);
-        filter_check_discard(call, entry, event);
-        ring_buffer_unlock_commit(tr->buffer, event);
+        if (!filter_check_discard(call, entry, tr->buffer, event))
+                ring_buffer_unlock_commit(tr->buffer, event);
 #endif
 }
 
@@ -1052,8 +1057,8 @@ static void ftrace_trace_userstack(struct trace_array *tr,
         trace.entries           = entry->caller;
 
         save_stack_trace_user(&trace);
-        filter_check_discard(call, entry, event);
-        ring_buffer_unlock_commit(tr->buffer, event);
+        if (!filter_check_discard(call, entry, tr->buffer, event))
+                ring_buffer_unlock_commit(tr->buffer, event);
 #endif
 }
 
@@ -1114,9 +1119,8 @@ tracing_sched_switch_trace(struct trace_array *tr,
         entry->next_state               = next->state;
         entry->next_cpu = task_cpu(next);
 
-        filter_check_discard(call, entry, event);
-
-        trace_buffer_unlock_commit(tr, event, flags, pc);
+        if (!filter_check_discard(call, entry, tr->buffer, event))
+                trace_buffer_unlock_commit(tr, event, flags, pc);
 }
 
 void
@@ -1142,9 +1146,8 @@ tracing_sched_wakeup_trace(struct trace_array *tr,
         entry->next_state               = wakee->state;
         entry->next_cpu                 = task_cpu(wakee);
 
-        filter_check_discard(call, entry, event);
-
-        ring_buffer_unlock_commit(tr->buffer, event);
+        if (!filter_check_discard(call, entry, tr->buffer, event))
+                ring_buffer_unlock_commit(tr->buffer, event);
         ftrace_trace_stack(tr, flags, 6, pc);
         ftrace_trace_userstack(tr, flags, pc);
 }
@@ -1285,8 +1288,8 @@ int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
         entry->fmt                      = fmt;
 
         memcpy(entry->buf, trace_buf, sizeof(u32) * len);
-        filter_check_discard(call, entry, event);
-        ring_buffer_unlock_commit(tr->buffer, event);
+        if (!filter_check_discard(call, entry, tr->buffer, event))
+                ring_buffer_unlock_commit(tr->buffer, event);
 
 out_unlock:
         __raw_spin_unlock(&trace_buf_lock);
@@ -1341,8 +1344,8 @@ int trace_vprintk(unsigned long ip, const char *fmt, va_list args)
 
         memcpy(&entry->buf, trace_buf, len);
         entry->buf[len] = 0;
-        filter_check_discard(call, entry, event);
-        ring_buffer_unlock_commit(tr->buffer, event);
+        if (!filter_check_discard(call, entry, tr->buffer, event))
+                ring_buffer_unlock_commit(tr->buffer, event);
 
  out_unlock:
         __raw_spin_unlock(&trace_buf_lock);
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index dfefffd7ae39..9729d14767d8 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -866,13 +866,21 @@ extern int filter_match_preds(struct ftrace_event_call *call, void *rec);
 extern void filter_free_subsystem_preds(struct event_subsystem *system);
 extern int filter_add_subsystem_pred(struct event_subsystem *system,
                                      struct filter_pred *pred);
+extern int filter_current_check_discard(struct ftrace_event_call *call,
+                                        void *rec,
+                                        struct ring_buffer_event *event);
 
-static inline void
+static inline int
 filter_check_discard(struct ftrace_event_call *call, void *rec,
+                     struct ring_buffer *buffer,
                      struct ring_buffer_event *event)
 {
-        if (unlikely(call->preds) && !filter_match_preds(call, rec))
-                ring_buffer_event_discard(event);
+        if (unlikely(call->preds) && !filter_match_preds(call, rec)) {
+                ring_buffer_discard_commit(buffer, event);
+                return 1;
+        }
+
+        return 0;
 }
 
 #define __common_field(type, item)                                      \
diff --git a/kernel/trace/trace_branch.c b/kernel/trace/trace_branch.c
index c95c25d838ef..8e64e604f5a7 100644
--- a/kernel/trace/trace_branch.c
+++ b/kernel/trace/trace_branch.c
@@ -74,9 +74,8 @@ probe_likely_condition(struct ftrace_branch_data *f, int val, int expect)
         entry->line = f->line;
         entry->correct = val == expect;
 
-        filter_check_discard(call, entry, event);
-
-        ring_buffer_unlock_commit(tr->buffer, event);
+        if (!filter_check_discard(call, entry, tr->buffer, event))
+                ring_buffer_unlock_commit(tr->buffer, event);
 
  out:
         atomic_dec(&tr->data[cpu]->disabled);
diff --git a/kernel/trace/trace_events_stage_3.h b/kernel/trace/trace_events_stage_3.h
index d2f34bf30e59..b2b298269eb0 100644
--- a/kernel/trace/trace_events_stage_3.h
+++ b/kernel/trace/trace_events_stage_3.h
@@ -222,11 +222,8 @@ static void ftrace_raw_event_##call(proto)				\
                                                                         \
         assign;                                                         \
                                                                         \
-        if (call->preds && !filter_match_preds(call, entry))            \
-                trace_current_buffer_discard_commit(event);             \
-        else                                                            \
+        if (!filter_current_check_discard(call, entry, event))          \
                 trace_nowake_buffer_unlock_commit(event, irq_flags, pc); \
-                                                                        \
 }                                                                       \
                                                                         \
 static int ftrace_raw_reg_event_##call(void)                            \
diff --git a/kernel/trace/trace_hw_branches.c b/kernel/trace/trace_hw_branches.c
index e6b275b22ac0..8683d50a753a 100644
--- a/kernel/trace/trace_hw_branches.c
+++ b/kernel/trace/trace_hw_branches.c
@@ -195,8 +195,8 @@ void trace_hw_branch(u64 from, u64 to)
         entry->ent.type = TRACE_HW_BRANCHES;
         entry->from = from;
         entry->to   = to;
-        filter_check_discard(call, entry, event);
-        trace_buffer_unlock_commit(tr, event, 0, 0);
+        if (!filter_check_discard(call, entry, tr->buffer, event))
+                trace_buffer_unlock_commit(tr, event, 0, 0);
 
  out:
         atomic_dec(&tr->data[cpu]->disabled);
diff --git a/kernel/trace/trace_power.c b/kernel/trace/trace_power.c
index 8ce7d7d62c07..810a5b7cf1c5 100644
--- a/kernel/trace/trace_power.c
+++ b/kernel/trace/trace_power.c
@@ -55,8 +55,8 @@ static void probe_power_end(struct power_trace *it)
                 goto out;
         entry   = ring_buffer_event_data(event);
         entry->state_data = *it;
-        filter_check_discard(call, entry, event);
-        trace_buffer_unlock_commit(tr, event, 0, 0);
+        if (!filter_check_discard(call, entry, tr->buffer, event))
+                trace_buffer_unlock_commit(tr, event, 0, 0);
  out:
         preempt_enable();
 }
@@ -87,8 +87,8 @@ static void probe_power_mark(struct power_trace *it, unsigned int type,
                 goto out;
         entry   = ring_buffer_event_data(event);
         entry->state_data = *it;
-        filter_check_discard(call, entry, event);
-        trace_buffer_unlock_commit(tr, event, 0, 0);
+        if (!filter_check_discard(call, entry, tr->buffer, event))
+                trace_buffer_unlock_commit(tr, event, 0, 0);
  out:
         preempt_enable();
 }