[PATCH v2 13/14] HID: logitech-hidpp: Avoid hidpp_connect_event() running while probe() restarts IO

[Hans de Goede <hdegoede@redhat.com>]

hidpp_probe() restarts IO after setting things up, if we get a connect
event just before hidpp_probe() stops all IO then hidpp_connect_event()
will be running from the workqueue and it will see IO errors.

To avoid this add an enable_connect_event flag and only set that
after the IO restart is done.

Since an hidpp_connect_event() run is queued after restarting IO
anyways, connect events before that run can safely be ignored.

Note this also means that hidpp_connect_event() is now guaranteed to
not get queued on hidpp_connect_and_start() failures so the work
for this no longer needs to be cancelled on failure.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
Changes in v2:
- Use an enable_connect_event flag instead of a mutex
---
 drivers/hid/hid-logitech-hidpp.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/hid/hid-logitech-hidpp.c b/drivers/hid/hid-logitech-hidpp.c
index 37213dcc9d9c..9e34a29619a0 100644
--- a/drivers/hid/hid-logitech-hidpp.c
+++ b/drivers/hid/hid-logitech-hidpp.c
@@ -192,6 +192,7 @@ struct hidpp_device {
 
 	void *private_data;
 
+	atomic_t enable_connect_event;
 	struct work_struct work;
 	struct kfifo delayed_work_fifo;
 	struct input_dev *delayed_input;
@@ -3892,6 +3893,9 @@ static int hidpp_raw_hidpp_event(struct hidpp_device *hidpp, u8 *data,
 	}
 
 	if (unlikely(hidpp_report_is_connect_event(hidpp, report))) {
+		if (!atomic_read(&hidpp->enable_connect_event))
+			return 1;
+
 		if (schedule_work(&hidpp->work) == 0)
 			dbg_hid("%s: connect event already queued\n", __func__);
 		return 1;
@@ -4501,6 +4505,7 @@ static int hidpp_probe(struct hid_device *hdev, const struct hid_device_id *id)
 	 * again (which may cause missing packets) queue hidpp_connect_event()
 	 * to check the connected state of the device.
 	 */
+	atomic_set(&hidpp->enable_connect_event, 1);
 	schedule_work(&hidpp->work);
 	flush_work(&hidpp->work);
 
@@ -4526,7 +4531,6 @@ static int hidpp_probe(struct hid_device *hdev, const struct hid_device_id *id)
 
 hid_hw_start_fail:
 	sysfs_remove_group(&hdev->dev.kobj, &ps_attribute_group);
-	cancel_work_sync(&hidpp->work);
 	mutex_destroy(&hidpp->send_mutex);
 	return ret;
 }
-- 
2.41.0