tracing: Make tracepoint_printk a static_key

Currently, when tracepoint_printk is set (enabled by the "tp_printk" kernel
command line), it causes trace events to print via printk(). This is a very
dangerous operation, but is useful for debugging.

The issue is, it's seldom used, but it is always checked even if it's not
enabled by the kernel command line. Instead of having this feature called by
a branch against a variable, turn that variable into a static key, and this
will remove the test and jump.

To simplify things, the functions output_printk() and
trace_event_buffer_commit() were moved from trace_events.c to trace.c.

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

1 files changed, 0 insertions, 40 deletions

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index ba67ede48822..d35fc2b0d304 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -283,46 +283,6 @@ void *trace_event_buffer_reserve(struct trace_event_buffer *fbuffer,
 }
 EXPORT_SYMBOL_GPL(trace_event_buffer_reserve);
 
-static DEFINE_SPINLOCK(tracepoint_iter_lock);
-
-static void output_printk(struct trace_event_buffer *fbuffer)
-{
-	struct trace_event_call *event_call;
-	struct trace_event *event;
-	unsigned long flags;
-	struct trace_iterator *iter = tracepoint_print_iter;
-
-	if (!iter)
-		return;
-
-	event_call = fbuffer->trace_file->event_call;
-	if (!event_call || !event_call->event.funcs ||
-	    !event_call->event.funcs->trace)
-		return;
-
-	event = &fbuffer->trace_file->event_call->event;
-
-	spin_lock_irqsave(&tracepoint_iter_lock, flags);
-	trace_seq_init(&iter->seq);
-	iter->ent = fbuffer->entry;
-	event_call->event.funcs->trace(iter, 0, event);
-	trace_seq_putc(&iter->seq, 0);
-	printk("%s", iter->seq.buffer);
-
-	spin_unlock_irqrestore(&tracepoint_iter_lock, flags);
-}
-
-void trace_event_buffer_commit(struct trace_event_buffer *fbuffer)
-{
-	if (tracepoint_printk)
-		output_printk(fbuffer);
-
-	event_trigger_unlock_commit(fbuffer->trace_file, fbuffer->buffer,
-				    fbuffer->event, fbuffer->entry,
-				    fbuffer->flags, fbuffer->pc);
-}
-EXPORT_SYMBOL_GPL(trace_event_buffer_commit);
-
 int trace_event_reg(struct trace_event_call *call,
 		    enum trace_reg type, void *data)
 {