hid-xpadneo, rumble: Protect concurrent access with spin locks

Otherwise we may work on a partially updated structure and that may leave the rumble motors running without letting the driver know it. Signed-off-by: Kai Krakow <[email protected]>
kakra · Jun 26, 2020 · e37ea45 · e37ea45
1 parent 44e7210
commit e37ea45
Showing 1 changed file with 18 additions and 5 deletions.
diff --git a/hid-xpadneo/src/hid-xpadneo.c b/hid-xpadneo/src/hid-xpadneo.c
@@ -134,6 +134,7 @@ struct xpadneo_devdata {
 	s32 last_abs_rz;
 
 	/* buffer for ff_worker */
+	spinlock_t ff_lock;
 	struct work_struct ff_worker;
 	struct ff_data ff;
 	struct ff_data ff_shadow;
@@ -207,6 +208,7 @@ static void xpadneo_ff_worker(struct work_struct *work)
 	struct hid_device *hdev = xdata->hdev;
 	struct ff_report *r = xdata->output_report_dmabuf;
 	int ret;
+	unsigned long flags;
 
 	memset(r, 0, sizeof(*r));
 	r->report_id = XPADNEO_XB1S_FF_REPORT;
@@ -227,6 +229,8 @@ static void xpadneo_ff_worker(struct work_struct *work)
 		r->ff.loop_count = U8_MAX;
 	}
 
+	spin_lock_irqsave(&xdata->ff_lock, flags);
+
 	if (unlikely(xdata->quirks & XPADNEO_QUIRK_NO_TRIGGER_RUMBLE)) {
 		/* do not send these bits if not supported */
 		r->ff.enable &= ~FF_RUMBLE_TRIGGERS;
@@ -251,12 +255,16 @@ static void xpadneo_ff_worker(struct work_struct *work)
 		r->ff.enable &= ~FF_RUMBLE_RIGHT;
 
 	/* do not send a report if nothing changed */
-	if (unlikely(r->ff.enable == FF_RUMBLE_NONE))
+	if (unlikely(r->ff.enable == FF_RUMBLE_NONE)) {
+		spin_unlock_irqrestore(&xdata->ff_lock, flags);
 		return;
+	}
 
 	/* shadow our current rumble values for the next cycle */
 	memcpy(&xdata->ff_shadow, &xdata->ff, sizeof(xdata->ff));
 
+	spin_unlock_irqrestore(&xdata->ff_lock, flags);
+
 	/* do not send these bits if not supported */
 	if (unlikely(xdata->quirks & XPADNEO_QUIRK_NO_MOTOR_MASK)) {
 		r->ff.enable = 0;
@@ -277,6 +285,7 @@ static int xpadneo_ff_play(struct input_dev *dev, void *data, struct ff_effect *
 		QUARTER = DIRECTION_LEFT,
 	};
 
+	unsigned long flags;
 	int fraction_TL, fraction_TR, fraction_MAIN;
 	s32 weak, strong, direction, max_damped, max_unscaled;
 
@@ -357,10 +366,6 @@ static int xpadneo_ff_play(struct input_dev *dev, void *data, struct ff_effect *
 		break;
 	}
 
-	/* calculate the physical magnitudes, scale from 16 bit to 0..100 */
-	xdata->ff.magnitude_strong = (u8)((strong * fraction_MAIN) / U16_MAX);
-	xdata->ff.magnitude_weak = (u8)((weak * fraction_MAIN) / U16_MAX);
-
 	/*
 	 * we want to keep the rumbling at the triggers at the maximum
 	 * of the weak and strong main rumble
@@ -376,10 +381,18 @@ static int xpadneo_ff_play(struct input_dev *dev, void *data, struct ff_effect *
 	else
 		max_damped = max_unscaled;
 
+	spin_lock_irqsave(&xdata->ff_lock, flags);
+
+	/* calculate the physical magnitudes, scale from 16 bit to 0..100 */
+	xdata->ff.magnitude_strong = (u8)((strong * fraction_MAIN) / U16_MAX);
+	xdata->ff.magnitude_weak = (u8)((weak * fraction_MAIN) / U16_MAX);
+
 	/* calculate the physical magnitudes, scale from 16 bit to 0..100 */
 	xdata->ff.magnitude_left = (u8)((max_damped * fraction_TL) / U16_MAX);
 	xdata->ff.magnitude_right = (u8)((max_damped * fraction_TR) / U16_MAX);
 
+	spin_unlock_irqrestore(&xdata->ff_lock, flags);
+
 	/* schedule writing a rumble report to the controller */
 	schedule_work(&xdata->ff_worker);
 	return 0;