pinctrl: st: avoid multiple mutex lock

Using the sysfs inteface to inspect the pins configuration the system can walk around a path which acquires the same mutex twice. On STiH407 platform, for example : cat /sys/kernel/debug/pinctrl/920f080.pin-controller-front0/pinconf-pins hangs the kernel and never returns. With this patch the mutex is temporary freed. Signed-off-by: Francesco Virlinzi <[email protected]> Signed-off-by: Patrice Chotard <[email protected]> Signed-off-by: Linus Walleij <[email protected]>
kyagi · Jan 7, 2015 · 96d16c3 · 96d16c3
1 parent f2dd028
commit 96d16c3
Showing 1 changed file with 3 additions and 1 deletion.
diff --git a/drivers/pinctrl/pinctrl-st.c b/drivers/pinctrl/pinctrl-st.c
@@ -1012,8 +1012,10 @@ static void st_pinconf_dbg_show(struct pinctrl_dev *pctldev,
 				   struct seq_file *s, unsigned pin_id)
 {
 	unsigned long config;
-	st_pinconf_get(pctldev, pin_id, &config);
 
+	mutex_unlock(&pctldev->mutex);
+	st_pinconf_get(pctldev, pin_id, &config);
+	mutex_lock(&pctldev->mutex);
 	seq_printf(s, "[OE:%ld,PU:%ld,OD:%ld]\n"
 		"\t\t[retime:%ld,invclk:%ld,clknotdat:%ld,"
 		"de:%ld,rt-clk:%ld,rt-delay:%ld]",