Input: Add proper locking when changing device's keymap

Take dev->event_lock to make sure that we don't race with input_event() and
also force key up event when removing a key from keymap table.

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

2 files changed, 75 insertions, 9 deletions

diff --git a/drivers/input/evdev.c b/drivers/input/evdev.c
index e5b4e9bfbdc5..0727b0a12557 100644
--- a/drivers/input/evdev.c
+++ b/drivers/input/evdev.c
@@ -617,7 +617,7 @@ static long evdev_do_ioctl(struct file *file, unsigned int cmd,
                 if (get_user(t, ip))
                         return -EFAULT;
 
-                error = dev->getkeycode(dev, t, &v);
+                error = input_get_keycode(dev, t, &v);
                 if (error)
                         return error;
 
@@ -630,7 +630,7 @@ static long evdev_do_ioctl(struct file *file, unsigned int cmd,
                 if (get_user(t, ip) || get_user(v, ip + 1))
                         return -EFAULT;
 
-                return dev->setkeycode(dev, t, v);
+                return input_set_keycode(dev, t, v);
 
         case EVIOCSFF:
                 if (copy_from_user(&effect, p, sizeof(effect)))
@@ -683,7 +683,7 @@ static long evdev_do_ioctl(struct file *file, unsigned int cmd,
                                 case EV_FF:  bits = dev->ffbit;  len = FF_MAX;  break;
                                 case EV_SW:  bits = dev->swbit;  len = SW_MAX;  break;
                                 default: return -EINVAL;
-                        }
+                                }
                                 return bits_to_user(bits, len, _IOC_SIZE(cmd), p, compat_mode);
                         }
 
diff --git a/drivers/input/input.c b/drivers/input/input.c
index a0be978501ff..e1729e1dd9b2 100644
--- a/drivers/input/input.c
+++ b/drivers/input/input.c
@@ -493,7 +493,7 @@ static void input_disconnect_device(struct input_dev *dev)
         if (is_event_supported(EV_KEY, dev->evbit, EV_MAX)) {
                 for (code = 0; code <= KEY_MAX; code++) {
                         if (is_event_supported(code, dev->keybit, KEY_MAX) &&
-                            test_bit(code, dev->key)) {
+                            __test_and_clear_bit(code, dev->key)) {
                                 input_pass_event(dev, EV_KEY, code, 0);
                         }
                 }
@@ -526,7 +526,7 @@ static int input_default_getkeycode(struct input_dev *dev,
         if (!dev->keycodesize)
                 return -EINVAL;
 
-        if (scancode < 0 || scancode >= dev->keycodemax)
+        if (scancode >= dev->keycodemax)
                 return -EINVAL;
 
         *keycode = input_fetch_keycode(dev, scancode);
@@ -540,10 +540,7 @@ static int input_default_setkeycode(struct input_dev *dev,
         int old_keycode;
         int i;
 
-        if (scancode < 0 || scancode >= dev->keycodemax)
-                return -EINVAL;
-
-        if (keycode < 0 || keycode > KEY_MAX)
+        if (scancode >= dev->keycodemax)
                 return -EINVAL;
 
         if (!dev->keycodesize)
@@ -586,6 +583,75 @@ static int input_default_setkeycode(struct input_dev *dev,
         return 0;
 }
 
+/**
+ * input_get_keycode - retrieve keycode currently mapped to a given scancode
+ * @dev: input device which keymap is being queried
+ * @scancode: scancode (or its equivalent for device in question) for which
+ *      keycode is needed
+ * @keycode: result
+ *
+ * This function should be called by anyone interested in retrieving current
+ * keymap. Presently keyboard and evdev handlers use it.
+ */
+int input_get_keycode(struct input_dev *dev, int scancode, int *keycode)
+{
+        if (scancode < 0)
+                return -EINVAL;
+
+        return dev->getkeycode(dev, scancode, keycode);
+}
+EXPORT_SYMBOL(input_get_keycode);
+
+/**
+ * input_get_keycode - assign new keycode to a given scancode
+ * @dev: input device which keymap is being updated
+ * @scancode: scancode (or its equivalent for device in question)
+ * @keycode: new keycode to be assigned to the scancode
+ *
+ * This function should be called by anyone needing to update current
+ * keymap. Presently keyboard and evdev handlers use it.
+ */
+int input_set_keycode(struct input_dev *dev, int scancode, int keycode)
+{
+        unsigned long flags;
+        int old_keycode;
+        int retval;
+
+        if (scancode < 0)
+                return -EINVAL;
+
+        if (keycode < 0 || keycode > KEY_MAX)
+                return -EINVAL;
+
+        spin_lock_irqsave(&dev->event_lock, flags);
+
+        retval = dev->getkeycode(dev, scancode, &old_keycode);
+        if (retval)
+                goto out;
+
+        retval = dev->setkeycode(dev, scancode, keycode);
+        if (retval)
+                goto out;
+
+        /*
+         * Simulate keyup event if keycode is not present
+         * in the keymap anymore
+         */
+        if (test_bit(EV_KEY, dev->evbit) &&
+            !is_event_supported(old_keycode, dev->keybit, KEY_MAX) &&
+            __test_and_clear_bit(old_keycode, dev->key)) {
+
+                input_pass_event(dev, EV_KEY, old_keycode, 0);
+                if (dev->sync)
+                        input_pass_event(dev, EV_SYN, SYN_REPORT, 1);
+        }
+
+ out:
+        spin_unlock_irqrestore(&dev->event_lock, flags);
+
+        return retval;
+}
+EXPORT_SYMBOL(input_set_keycode);
 
 #define MATCH_BIT(bit, max) \
                 for (i = 0; i < BITS_TO_LONGS(max); i++) \