blktrace: make blk_tracer_enabled a bool flag

It doesn't have to be a counter, and it can be a bool flag instead.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <49C2F5D3.8090104@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index fb3bc53835dd5a1c20bfb7c462975654bef1cffa..73845b7968bb266154a4f8974a8be1ad7221cae7 100644 (file)
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -30,7 +30,7 @@
 static unsigned int blktrace_seq __read_mostly = 1;
 
 static struct trace_array *blk_tr;
-static int __read_mostly  blk_tracer_enabled;
+static bool blk_tracer_enabled __read_mostly;
 
 /* Select an alternative, minimalistic output than the original one */
 #define TRACE_BLK_OPT_CLASSIC  0x1
@@ -1111,9 +1111,7 @@ static int blk_tracer_init(struct trace_array *tr)
 {
        blk_tr = tr;
        blk_tracer_start(tr);
-       mutex_lock(&blk_probe_mutex);
-       blk_tracer_enabled++;
-       mutex_unlock(&blk_probe_mutex);
+       blk_tracer_enabled = true;
        return 0;
 }
 
@@ -1131,11 +1129,7 @@ static void blk_tracer_reset(struct trace_array *tr)
        if (!atomic_read(&blk_probes_ref))
                return;
 
-       mutex_lock(&blk_probe_mutex);
-       blk_tracer_enabled--;
-       WARN_ON(blk_tracer_enabled < 0);
-       mutex_unlock(&blk_probe_mutex);
-
+       blk_tracer_enabled = false;
        blk_tracer_stop(tr);
 }