clkdev: Fix race condition in clock lookup from device tree

[firefly-linux-kernel-4.4.55.git] / drivers / clk / clkdev.c

diff --git a/drivers/clk/clkdev.c b/drivers/clk/clkdev.c
index 442a31363873d35f319e0d5ee5b6b250084c02fc..48f67218247cb0cb44cfa92b8ed4903a0f193531 100644 (file)
--- a/drivers/clk/clkdev.c
+++ b/drivers/clk/clkdev.c
@@ -21,6 +21,8 @@
 #include <linux/clkdev.h>
 #include <linux/of.h>
 
+#include "clk.h"
+
 static LIST_HEAD(clocks);
 static DEFINE_MUTEX(clocks_mutex);
 
@@ -39,7 +41,13 @@ struct clk *of_clk_get(struct device_node *np, int index)
        if (rc)
                return ERR_PTR(rc);
 
-       clk = of_clk_get_from_provider(&clkspec);
+       of_clk_lock();
+       clk = __of_clk_get_from_provider(&clkspec);
+
+       if (!IS_ERR(clk) && !__clk_get(clk))
+               clk = ERR_PTR(-ENOENT);
+
+       of_clk_unlock();
        of_node_put(clkspec.np);
        return clk;
 }
@@ -157,7 +165,7 @@ struct clk *clk_get(struct device *dev, const char *con_id)
 
        if (dev) {
                clk = of_clk_get_by_name(dev->of_node, con_id);
-               if (!IS_ERR(clk) && __clk_get(clk))
+               if (!IS_ERR(clk))
                        return clk;
        }