watchdog: cpwd: use generic compat_ptr_ioctl

The cpwd_compat_ioctl() contains a bogus mutex that dates
back to a leftover BKL instance.

Simplify the implementation by using the new compat_ptr_ioctl()
helper function that will do the right thing for all calls
here.

Note that WIOCSTART/WIOCSTOP don't take any arguments, so
the compat_ptr() conversion is not needed here, but it also
doesn't hurt.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20190814204259.120942-6-arnd@arndb.de
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

1 files changed, 1 insertions, 24 deletions

diff --git a/drivers/watchdog/cpwd.c b/drivers/watchdog/cpwd.c
index b973b31179df..9393be584e72 100644
--- a/drivers/watchdog/cpwd.c
+++ b/drivers/watchdog/cpwd.c
@@ -473,29 +473,6 @@ static long cpwd_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
         return 0;
 }
 
-static long cpwd_compat_ioctl(struct file *file, unsigned int cmd,
-                              unsigned long arg)
-{
-        int rval = -ENOIOCTLCMD;
-
-        switch (cmd) {
-        /* solaris ioctls are specific to this driver */
-        case WIOCSTART:
-        case WIOCSTOP:
-        case WIOCGSTAT:
-                mutex_lock(&cpwd_mutex);
-                rval = cpwd_ioctl(file, cmd, arg);
-                mutex_unlock(&cpwd_mutex);
-                break;
-
-        /* everything else is handled by the generic compat layer */
-        default:
-                break;
-        }
-
-        return rval;
-}
-
 static ssize_t cpwd_write(struct file *file, const char __user *buf,
                           size_t count, loff_t *ppos)
 {
@@ -520,7 +497,7 @@ static ssize_t cpwd_read(struct file *file, char __user *buffer,
 static const struct file_operations cpwd_fops = {
         .owner =                THIS_MODULE,
         .unlocked_ioctl =       cpwd_ioctl,
-        .compat_ioctl =         cpwd_compat_ioctl,
+        .compat_ioctl =         compat_ptr_ioctl,
         .open =                 cpwd_open,
         .write =                cpwd_write,
         .read =                 cpwd_read,