tracing: Separate out trace events from global variables

The trace events for ftrace are all defined via global variables.
The arrays of events and event systems are linked to a global list.
This prevents multiple users of the event system (what to enable and
what not to).

By adding descriptors to represent the event/file relation, as well
as to which trace_array descriptor they are associated with, allows
for more than one set of events to be defined. Once the trace events
files have a link between the trace event and the trace_array they
are associated with, we can create multiple trace_arrays that can
record separate events in separate buffers.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

6 files changed, 622 insertions, 260 deletions

diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h
index 13a54d0bdfa8..c7191d482f98 100644
--- a/include/linux/ftrace_event.h
+++ b/include/linux/ftrace_event.h
@@ -182,18 +182,20 @@ extern int ftrace_event_reg(struct ftrace_event_call *event,
                             enum trace_reg type, void *data);
 
 enum {
-        TRACE_EVENT_FL_ENABLED_BIT,
         TRACE_EVENT_FL_FILTERED_BIT,
-        TRACE_EVENT_FL_RECORDED_CMD_BIT,
         TRACE_EVENT_FL_CAP_ANY_BIT,
         TRACE_EVENT_FL_NO_SET_FILTER_BIT,
         TRACE_EVENT_FL_IGNORE_ENABLE_BIT,
 };
 
+/*
+ * Event flags:
+ *  FILTERED      - The event has a filter attached
+ *  CAP_ANY       - Any user can enable for perf
+ *  NO_SET_FILTER - Set when filter has error and is to be ignored
+ */
 enum {
-        TRACE_EVENT_FL_ENABLED          = (1 << TRACE_EVENT_FL_ENABLED_BIT),
         TRACE_EVENT_FL_FILTERED         = (1 << TRACE_EVENT_FL_FILTERED_BIT),
-        TRACE_EVENT_FL_RECORDED_CMD     = (1 << TRACE_EVENT_FL_RECORDED_CMD_BIT),
         TRACE_EVENT_FL_CAP_ANY          = (1 << TRACE_EVENT_FL_CAP_ANY_BIT),
         TRACE_EVENT_FL_NO_SET_FILTER    = (1 << TRACE_EVENT_FL_NO_SET_FILTER_BIT),
         TRACE_EVENT_FL_IGNORE_ENABLE    = (1 << TRACE_EVENT_FL_IGNORE_ENABLE_BIT),
@@ -203,12 +205,44 @@ struct ftrace_event_call {
         struct list_head        list;
         struct ftrace_event_class *class;
         char                    *name;
-        struct dentry           *dir;
         struct trace_event      event;
         const char              *print_fmt;
         struct event_filter     *filter;
+        struct list_head        *files;
         void                    *mod;
         void                    *data;
+        int                     flags; /* static flags of different events */
+
+#ifdef CONFIG_PERF_EVENTS
+        int                             perf_refcount;
+        struct hlist_head __percpu      *perf_events;
+#endif
+};
+
+struct trace_array;
+struct ftrace_subsystem_dir;
+
+enum {
+        FTRACE_EVENT_FL_ENABLED_BIT,
+        FTRACE_EVENT_FL_RECORDED_CMD_BIT,
+};
+
+/*
+ * Ftrace event file flags:
+ *  ENABELD       - The event is enabled
+ *  RECORDED_CMD  - The comms should be recorded at sched_switch
+ */
+enum {
+        FTRACE_EVENT_FL_ENABLED         = (1 << FTRACE_EVENT_FL_ENABLED_BIT),
+        FTRACE_EVENT_FL_RECORDED_CMD    = (1 << FTRACE_EVENT_FL_RECORDED_CMD_BIT),
+};
+
+struct ftrace_event_file {
+        struct list_head                list;
+        struct ftrace_event_call        *event_call;
+        struct dentry                   *dir;
+        struct trace_array              *tr;
+        struct ftrace_subsystem_dir     *system;
 
         /*
          * 32 bit flags:
@@ -223,17 +257,12 @@ struct ftrace_event_call {
          *
          * Note: Reads of flags do not hold the event_mutex since
          * they occur in critical sections. But the way flags
-         * is currently used, these changes do no affect the code
+         * is currently used, these changes do not affect the code
          * except that when a change is made, it may have a slight
          * delay in propagating the changes to other CPUs due to
          * caching and such.
          */
         unsigned int            flags;
-
-#ifdef CONFIG_PERF_EVENTS
-        int                             perf_refcount;
-        struct hlist_head __percpu      *perf_events;
-#endif
 };
 
 #define __TRACE_EVENT_FLAGS(name, value)                                \
diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h
index 40dc5e8fe340..191d9661e277 100644
--- a/include/trace/ftrace.h
+++ b/include/trace/ftrace.h
@@ -518,7 +518,8 @@ static inline notrace int ftrace_get_offsets_##call(			\
 static notrace void                                                     \
 ftrace_raw_event_##call(void *__data, proto)                            \
 {                                                                       \
-        struct ftrace_event_call *event_call = __data;                  \
+        struct ftrace_event_file *ftrace_file = __data;                 \
+        struct ftrace_event_call *event_call = ftrace_file->event_call; \
         struct ftrace_data_offsets_##call __maybe_unused __data_offsets;\
         struct ring_buffer_event *event;                                \
         struct ftrace_raw_##call *entry;                                \
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 4f1dade56981..932931897b8d 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -189,6 +189,8 @@ unsigned long long ns2usecs(cycle_t nsec)
  */
 static struct trace_array       global_trace;
 
+LIST_HEAD(ftrace_trace_arrays);
+
 static DEFINE_PER_CPU(struct trace_array_cpu, global_trace_cpu);
 
 int filter_current_check_discard(struct ring_buffer *buffer,
@@ -5359,6 +5361,12 @@ __init static int tracer_alloc_buffers(void)
 
         register_die_notifier(&trace_die_notifier);
 
+        global_trace.flags = TRACE_ARRAY_FL_GLOBAL;
+
+        INIT_LIST_HEAD(&global_trace.systems);
+        INIT_LIST_HEAD(&global_trace.events);
+        list_add(&global_trace.list, &ftrace_trace_arrays);
+
         while (trace_boot_options) {
                 char *option;
 
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 2081971367ea..037f7eb03d69 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -158,13 +158,39 @@ struct trace_array_cpu {
  */
 struct trace_array {
         struct ring_buffer      *buffer;
+        struct list_head        list;
         int                     cpu;
         int                     buffer_disabled;
+        unsigned int            flags;
         cycle_t                 time_start;
+        struct dentry           *dir;
+        struct dentry           *event_dir;
+        struct list_head        systems;
+        struct list_head        events;
         struct task_struct      *waiter;
         struct trace_array_cpu  *data[NR_CPUS];
 };
 
+enum {
+        TRACE_ARRAY_FL_GLOBAL   = (1 << 0)
+};
+
+extern struct list_head ftrace_trace_arrays;
+
+/*
+ * The global tracer (top) should be the first trace array added,
+ * but we check the fl