Input: add semaphore and user count to input_dev structure;

       serialize open and close calls and ensure that device's
       open and close methods are only called when first user
       opens it or last user closes it.

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

1 files changed, 4 insertions, 0 deletions

diff --git a/include/linux/input.h b/include/linux/input.h
index 72731d7d189e..43e8ecec602b 100644
--- a/include/linux/input.h
+++ b/include/linux/input.h
@@ -859,6 +859,10 @@ struct input_dev {
         int (*erase_effect)(struct input_dev *dev, int effect_id);
 
         struct input_handle *grab;
+
+        struct semaphore sem;   /* serializes open and close operations */
+        unsigned int users;
+
         struct device *dev;
 
         struct list_head        h_list;