Export blk_fill_rwbs()

Exported so it can be used by bcache's tracepoints

Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Steven Rostedt <rostedt@goodmis.org>
CC: Frederic Weisbecker <fweisbec@gmail.com>
CC: Ingo Molnar <mingo@redhat.com>

kernel/trace/blktrace.c

diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index 9e5b8c2..20d8a98 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -1828,6 +1828,7 @@
 
 	rwbs[i] = '\0';
 }
+EXPORT_SYMBOL_GPL(blk_fill_rwbs);
 
 #endif /* CONFIG_EVENT_TRACING */