[PATCH] HID: logitech-dj: Fix error handling in logi_dj_recv_switch_to_dj_mode()

[Nikita Zhandarovich]

Presently, if a call to logi_dj_recv_send_report() fails, we do
not learn about the error until after sending short
HID_OUTPUT_REPORT with hid_hw_raw_request().
To handle this somewhat unlikely issue, return on error in
logi_dj_recv_send_report() (minding ugly sleep workaround) and
take into account the result of hid_hw_raw_request().

Found by Linux Verification Center (linuxtesting.org) with static
analysis tool SVACE.

Fixes: 6a9ddc897883 ("HID: logitech-dj: enable notifications on connect/disconnect")
Signed-off-by: Nikita Zhandarovich <n.zhandarovich@xxxxxxxxxx>
---
 drivers/hid/hid-logitech-dj.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/hid/hid-logitech-dj.c b/drivers/hid/hid-logitech-dj.c
index 62180414efcc..e6a8b6d8eab7 100644
--- a/drivers/hid/hid-logitech-dj.c
+++ b/drivers/hid/hid-logitech-dj.c
@@ -1285,6 +1285,9 @@ static int logi_dj_recv_switch_to_dj_mode(struct dj_receiver_dev *djrcv_dev,
 		 * 50 msec should gives enough time to the receiver to be ready.
 		 */
 		msleep(50);
+
+		if (retval)
+			return retval;
 	}
 
 	/*
@@ -1306,7 +1309,7 @@ static int logi_dj_recv_switch_to_dj_mode(struct dj_receiver_dev *djrcv_dev,
 	buf[5] = 0x09;
 	buf[6] = 0x00;
 
-	hid_hw_raw_request(hdev, REPORT_ID_HIDPP_SHORT, buf,
+	retval = hid_hw_raw_request(hdev, REPORT_ID_HIDPP_SHORT, buf,
 			HIDPP_REPORT_SHORT_LENGTH, HID_OUTPUT_REPORT,
 			HID_REQ_SET_REPORT);
 
-- 
2.25.1