Revert "Input: do not pass injected events back to the originating handler"

This reverts commit 5fdbe44d.

Apparently there exist userspace programs that expect to be able to
"loop back" and distribute to readers events written into
/dev/input/eventX and this change made for the benefit of SysRq
handler broke them. Now that SysRq uses alternative method to suppress
filtering of the events it re-injects we can safely revert this change.
Reported-by: NKristen Carlson Accardi <kristen@linux.intel.com>
Cc: stable@kernel.org
Signed-off-by: NDmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/input.c

@@ -76,7 +76,6 @@ static int input_defuzz_abs_event(int value, int old_val, int fuzz)
  * dev->event_lock held and interrupts disabled.
  */
 static void input_pass_event(struct input_dev *dev,
-			     struct input_handler *src_handler,
 			     unsigned int type, unsigned int code, int value)
 {
 	struct input_handler *handler;
@@ -95,15 +94,6 @@ static void input_pass_event(struct input_dev *dev,
 				continue;
 
 			handler = handle->handler;
-
-			/*
-			 * If this is the handler that injected this
-			 * particular event we want to skip it to avoid
-			 * filters firing again and again.
-			 */
-			if (handler == src_handler)
-				continue;
-
 			if (!handler->filter) {
 				if (filtered)
 					break;
@@ -133,7 +123,7 @@ static void input_repeat_key(unsigned long data)
 	if (test_bit(dev->repeat_key, dev->key) &&
 	    is_event_supported(dev->repeat_key, dev->keybit, KEY_MAX)) {
 
-		input_pass_event(dev, NULL, EV_KEY, dev->repeat_key, 2);
+		input_pass_event(dev, EV_KEY, dev->repeat_key, 2);
 
 		if (dev->sync) {
 			/*
@@ -142,7 +132,7 @@ static void input_repeat_key(unsigned long data)
 			 * Otherwise assume that the driver will send
 			 * SYN_REPORT once it's done.
 			 */
-			input_pass_event(dev, NULL, EV_SYN, SYN_REPORT, 1);
+			input_pass_event(dev, EV_SYN, SYN_REPORT, 1);
 		}
 
 		if (dev->rep[REP_PERIOD])
@@ -175,7 +165,6 @@ static void input_stop_autorepeat(struct input_dev *dev)
 #define INPUT_PASS_TO_ALL	(INPUT_PASS_TO_HANDLERS | INPUT_PASS_TO_DEVICE)
 
 static int input_handle_abs_event(struct input_dev *dev,
-				  struct input_handler *src_handler,
 				  unsigned int code, int *pval)
 {
 	bool is_mt_event;
@@ -219,15 +208,13 @@ static int input_handle_abs_event(struct input_dev *dev,
 	/* Flush pending "slot" event */
 	if (is_mt_event && dev->slot != input_abs_get_val(dev, ABS_MT_SLOT)) {
 		input_abs_set_val(dev, ABS_MT_SLOT, dev->slot);
-		input_pass_event(dev, src_handler,
-				 EV_ABS, ABS_MT_SLOT, dev->slot);
+		input_pass_event(dev, EV_ABS, ABS_MT_SLOT, dev->slot);
 	}
 
 	return INPUT_PASS_TO_HANDLERS;
 }
 
 static void input_handle_event(struct input_dev *dev,
-			       struct input_handler *src_handler,
 			       unsigned int type, unsigned int code, int value)
 {
 	int disposition = INPUT_IGNORE_EVENT;
@@ -280,8 +267,7 @@ static void input_handle_event(struct input_dev *dev,
 
 	case EV_ABS:
 		if (is_event_supported(code, dev->absbit, ABS_MAX))
-			disposition = input_handle_abs_event(dev, src_handler,
-							     code, &value);
+			disposition = input_handle_abs_event(dev, code, &value);
 
 		break;
 
@@ -339,7 +325,7 @@ static void input_handle_event(struct input_dev *dev,
 		dev->event(dev, type, code, value);
 
 	if (disposition & INPUT_PASS_TO_HANDLERS)
-		input_pass_event(dev, src_handler, type, code, value);
+		input_pass_event(dev, type, code, value);
 }
 
 /**
@@ -368,7 +354,7 @@ void input_event(struct input_dev *dev,
 
 		spin_lock_irqsave(&dev->event_lock, flags);
 		add_input_randomness(type, code, value);
-		input_handle_event(dev, NULL, type, code, value);
+		input_handle_event(dev, type, code, value);
 		spin_unlock_irqrestore(&dev->event_lock, flags);
 	}
 }
@@ -398,8 +384,7 @@ void input_inject_event(struct input_handle *handle,
 		rcu_read_lock();
 		grab = rcu_dereference(dev->grab);
 		if (!grab || grab == handle)
-			input_handle_event(dev, handle->handler,
-					   type, code, value);
+			input_handle_event(dev, type, code, value);
 		rcu_read_unlock();
 
 		spin_unlock_irqrestore(&dev->event_lock, flags);
@@ -612,10 +597,10 @@ static void input_dev_release_keys(struct input_dev *dev)
 		for (code = 0; code <= KEY_MAX; code++) {
 			if (is_event_supported(code, dev->keybit, KEY_MAX) &&
 			    __test_and_clear_bit(code, dev->key)) {
-				input_pass_event(dev, NULL, EV_KEY, code, 0);
+				input_pass_event(dev, EV_KEY, code, 0);
 			}
 		}
-		input_pass_event(dev, NULL, EV_SYN, SYN_REPORT, 1);
+		input_pass_event(dev, EV_SYN, SYN_REPORT, 1);
 	}
 }
 
@@ -890,9 +875,9 @@ int input_set_keycode(struct input_dev *dev,
 	    !is_event_supported(old_keycode, dev->keybit, KEY_MAX) &&
 	    __test_and_clear_bit(old_keycode, dev->key)) {
 
-		input_pass_event(dev, NULL, EV_KEY, old_keycode, 0);
+		input_pass_event(dev, EV_KEY, old_keycode, 0);
 		if (dev->sync)
-			input_pass_event(dev, NULL, EV_SYN, SYN_REPORT, 1);
+			input_pass_event(dev, EV_SYN, SYN_REPORT, 1);
 	}
 
  out: