[WATCHDOG] w836?7hf_wdt spinlock fixes.
Add io spinlocks to prevent possible race
conditions between start and stop operations
that are issued from different child processes
where the master process opened /dev/watchdog.
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
diff --git a/drivers/char/watchdog/w83697hf_wdt.c b/drivers/char/watchdog/w83697hf_wdt.c
index ef6612e..21e822e 100644
--- a/drivers/char/watchdog/w83697hf_wdt.c
+++ b/drivers/char/watchdog/w83697hf_wdt.c
@@ -33,6 +33,7 @@
#include <linux/notifier.h>
#include <linux/reboot.h>
#include <linux/init.h>
+#include <linux/spinlock.h>
#include <asm/io.h>
#include <asm/uaccess.h>
@@ -44,6 +45,7 @@
static unsigned long wdt_is_open;
static char expect_close;
+static spinlock_t io_lock;
/* You must set this - there is no sane way to probe for this board. */
static int wdt_io = 0x2E;
@@ -114,12 +116,16 @@
static void
wdt_ctrl(int timeout)
{
+ spin_lock(&io_lock);
+
w83697hf_select_wd_register();
outb_p(0xF4, WDT_EFER); /* Select CRF4 */
outb_p(timeout, WDT_EFDR); /* Write Timeout counter to CRF4 */
w83697hf_unselect_wd_register();
+
+ spin_unlock(&io_lock);
}
static int
@@ -307,6 +313,8 @@
{
int ret;
+ spin_lock_init(&io_lock);
+
printk(KERN_INFO "WDT driver for the Winbond(TM) W83697HF Super I/O chip initialising.\n");
if (wdt_set_heartbeat(timeout)) {