1 files changed, 19 insertions, 0 deletions

diff --git a/drivers/hid/hid-wiimote.c b/drivers/hid/hid-wiimote.c
index deaf23207812..3416f69302cd 100644
--- a/drivers/hid/hid-wiimote.c
+++ b/drivers/hid/hid-wiimote.c
@@ -10,6 +10,7 @@
  * any later version.
  */
 
+#include <linux/atomic.h>
 #include <linux/device.h>
 #include <linux/hid.h>
 #include <linux/input.h>
@@ -20,6 +21,7 @@
 #define WIIMOTE_NAME "Nintendo Wii Remote"
 
 struct wiimote_data {
+        atomic_t ready;
         struct hid_device *hdev;
         struct input_dev *input;
 };
@@ -27,12 +29,26 @@ struct wiimote_data {
 static int wiimote_input_event(struct input_dev *dev, unsigned int type,
                                                 unsigned int code, int value)
 {
+        struct wiimote_data *wdata = input_get_drvdata(dev);
+
+        if (!atomic_read(&wdata->ready))
+                return -EBUSY;
+        /* smp_rmb: Make sure wdata->xy is available when wdata->ready is 1 */
+        smp_rmb();
+
         return 0;
 }
 
 static int wiimote_hid_event(struct hid_device *hdev, struct hid_report *report,
                                                         u8 *raw_data, int size)
 {
+        struct wiimote_data *wdata = hid_get_drvdata(hdev);
+
+        if (!atomic_read(&wdata->ready))
+                return -EBUSY;
+        /* smp_rmb: Make sure wdata->xy is available when wdata->ready is 1 */
+        smp_rmb();
+
         if (size < 1)
                 return -EINVAL;
 
@@ -103,6 +119,9 @@ static int wiimote_hid_probe(struct hid_device *hdev,
                 goto err_stop;
         }
 
+        /* smp_wmb: Write wdata->xy first before wdata->ready is set to 1 */
+        smp_wmb();
+        atomic_set(&wdata->ready, 1);
         hid_info(hdev, "New device registered\n");
         return 0;