i2c: Use rwsem instead of mutex for board info

By using rwsem we can easily manage recursive calls of
i2c_scan_static_board_info() function without breaking the locking.

Signed-off-by: Rodolfo Giometti <giometti@linux.it>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

1 files changed, 3 insertions, 1 deletions

diff --git a/drivers/i2c/i2c-core.h b/drivers/i2c/i2c-core.h
index cd5bff874855..9f9c57ff6708 100644
--- a/drivers/i2c/i2c-core.h
+++ b/drivers/i2c/i2c-core.h
@@ -16,6 +16,8 @@
  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
 
+#include <linux/rwsem.h>
+
 struct i2c_devinfo {
         struct list_head        list;
         int                     busnum;
@@ -25,7 +27,7 @@ struct i2c_devinfo {
 /* board_lock protects board_list and first_dynamic_bus_num.
  * only i2c core components are allowed to use these symbols.
  */
-extern struct mutex     __i2c_board_lock;
+extern struct rw_semaphore      __i2c_board_lock;
 extern struct list_head __i2c_board_list;
 extern int              __i2c_first_dynamic_bus_num;