tracing: Encapsulate global_trace and remove dependencies on global vars

The global_trace variable in kernel/trace/trace.c has been kept 'static' and
local to that file so that it would not be used too much outside of that
file. This has paid off, even though there were lots of changes to make
the trace_array structure more generic (not depending on global_trace).

Removal of a lot of direct usages of global_trace is needed to be able to
create more trace_arrays such that we can add multiple buffers.

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

1 files changed, 20 insertions, 1 deletions

diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index da09a037abcd..b80fbcf70af4 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -127,12 +127,21 @@ enum trace_flag_type {
 
 #define TRACE_BUF_SIZE          1024
 
+struct trace_array;
+
+struct trace_cpu {
+        struct trace_array      *tr;
+        struct dentry           *dir;
+        int                     cpu;
+};
+
 /*
  * The CPU trace array - it consists of thousands of trace entries
  * plus some other descriptor data: (for example which task started
  * the trace, etc.)
  */
 struct trace_array_cpu {
+        struct trace_cpu        trace_cpu;
         atomic_t                disabled;
         void                    *buffer_page;   /* ring buffer spare */
 
@@ -151,6 +160,8 @@ struct trace_array_cpu {
         char                    comm[TASK_COMM_LEN];
 };
 
+struct tracer;
+
 /*
  * The trace array - an array of per-CPU trace arrays. This is the
  * highest level data structure that individual tracers deal with.
@@ -161,9 +172,16 @@ struct trace_array {
         struct list_head        list;
         int                     cpu;
         int                     buffer_disabled;
+        struct trace_cpu        trace_cpu;      /* place holder */
+        int                     stop_count;
+        int                     clock_id;
+        struct tracer           *current_trace;
         unsigned int            flags;
         cycle_t                 time_start;
+        raw_spinlock_t          start_lock;
         struct dentry           *dir;
+        struct dentry           *options;
+        struct dentry           *percpu_dir;
         struct dentry           *event_dir;
         struct list_head        systems;
         struct list_head        events;
@@ -474,6 +492,7 @@ struct dentry *trace_create_file(const char *name,
                                  void *data,
                                  const struct file_operations *fops);
 
+struct dentry *tracing_init_dentry_tr(struct trace_array *tr);
 struct dentry *tracing_init_dentry(void);
 
 struct ring_buffer_event;
@@ -979,7 +998,7 @@ extern const char *__stop___trace_bprintk_fmt[];
 void trace_printk_init_buffers(void);
 void trace_printk_start_comm(void);
 int trace_keep_overwrite(struct tracer *tracer, u32 mask, int set);
-int set_tracer_flag(unsigned int mask, int enabled);
+int set_tracer_flag(struct trace_array *tr, unsigned int mask, int enabled);
 
 #undef FTRACE_ENTRY
 #define FTRACE_ENTRY(call, struct_name, id, tstruct, print, filter)     \