Input: mac mouse emulation - add locking

We need to add appropriate locking when toggling mac mouse emulation
on and off to ensure that input device and handler are in consistent
state.

Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

1 files changed, 8 insertions, 0 deletions

diff --git a/drivers/macintosh/mac_hid.c b/drivers/macintosh/mac_hid.c
index 067f9962f499..6a82388505f0 100644
--- a/drivers/macintosh/mac_hid.c
+++ b/drivers/macintosh/mac_hid.c
@@ -23,6 +23,8 @@ static int mouse_button3_keycode = KEY_RIGHTALT;	/* right option key */
 
 static struct input_dev *mac_hid_emumouse_dev;
 
+static DEFINE_MUTEX(mac_hid_emumouse_mutex);
+
 static int mac_hid_create_emumouse(void)
 {
         static struct lock_class_key mac_hid_emumouse_dev_event_class;
@@ -187,6 +189,10 @@ static int mac_hid_toggle_emumouse(ctl_table *table, int write,
         int old_val = *valp;
         int rc;
 
+        rc = mutex_lock_killable(&mac_hid_emumouse_mutex);
+        if (rc)
+                return rc;
+
         rc = proc_dointvec(table, write, buffer, lenp, ppos);
 
         if (rc == 0 && write && *valp != old_val) {
@@ -202,6 +208,8 @@ static int mac_hid_toggle_emumouse(ctl_table *table, int write,
         if (rc)
                 *valp = old_val;
 
+        mutex_unlock(&mac_hid_emumouse_mutex);
+
         return rc;
 }