Bluetooth: hidp: Fix assumptions on the return value of hidp_send_message

hidp_send_message was changed to return non-zero values on success,
which some other bits did not expect. This caused spurious errors to be
propagated through the stack, breaking some drivers, such as hid-sony
for the Dualshock 4 in Bluetooth mode.

As pointed out by Dan Carpenter, hid-microsoft directly relied on that
assumption as well.

Fixes: 48d9cc9d ("Bluetooth: hidp: Let hidp_send_message return number of queued bytes")
Signed-off-by: Dan Elkouby <streetwalkermc@gmail.com>
Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

drivers/hid/hid-microsoft.c

@@ -303,7 +303,7 @@ static void ms_ff_worker(struct work_struct *work)
 	r->magnitude[MAGNITUDE_WEAK] = ms->weak;     /* right actuator */
 
 	ret = hid_hw_output_report(hdev, (__u8 *)r, sizeof(*r));
-	if (ret)
+	if (ret < 0)
 		hid_warn(hdev, "failed to send FF report\n");
 }
 

net/bluetooth/hidp/core.c

@@ -267,7 +267,7 @@ static int hidp_get_raw_report(struct hid_device *hid,
 	set_bit(HIDP_WAITING_FOR_RETURN, &session->flags);
 	data[0] = report_number;
 	ret = hidp_send_ctrl_message(session, report_type, data, 1);
-	if (ret)
+	if (ret < 0)
 		goto err;
 
 	/* Wait for the return of the report. The returned report
@@ -343,7 +343,7 @@ static int hidp_set_raw_report(struct hid_device *hid, unsigned char reportnum,
 	data[0] = reportnum;
 	set_bit(HIDP_WAITING_FOR_SEND_ACK, &session->flags);
 	ret = hidp_send_ctrl_message(session, report_type, data, count);
-	if (ret)
+	if (ret < 0)
 		goto err;
 
 	/* Wait for the ACK from the device. */