linux-kernel - [PATCH] Input: exc3000 - Fix return value check of wait_for_completion

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Date:   Mon, 11 Apr 2022 10:58:23 +0000
From:   Miaoqian Lin <linmq006@...il.com>
To:     Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Miaoqian Lin <linmq006@...il.com>,
        Lucas Stach <l.stach@...gutronix.de>,
        linux-input@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH] Input: exc3000 - Fix return value check of wait_for_completion_timeout

wait_for_completion_timeout() returns unsigned long not int.
It returns 0 if timed out, and positive if completed.
The check for <= 0 is ambiguous and should be == 0 here
indicating timeout which is the only error case.

Fixes: 102feb1ddfd0 ("Input: exc3000 - factor out vendor data request")
Signed-off-by: Miaoqian Lin <linmq006@...il.com>
---
 drivers/input/touchscreen/exc3000.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/input/touchscreen/exc3000.c b/drivers/input/touchscreen/exc3000.c
index cbe0dd412912..b290a0bb26cf 100644
--- a/drivers/input/touchscreen/exc3000.c
+++ b/drivers/input/touchscreen/exc3000.c
@@ -220,6 +220,7 @@ static int exc3000_vendor_data_request(struct exc3000_data *data, u8 *request,
 {
 	u8 buf[EXC3000_LEN_VENDOR_REQUEST] = { 0x67, 0x00, 0x42, 0x00, 0x03 };
 	int ret;
+	unsigned long time_left;
 
 	mutex_lock(&data->query_lock);
 
@@ -233,9 +234,9 @@ static int exc3000_vendor_data_request(struct exc3000_data *data, u8 *request,
 		goto out_unlock;
 
 	if (response) {
-		ret = wait_for_completion_timeout(&data->wait_event,
+		time_left = wait_for_completion_timeout(&data->wait_event,
 						  timeout * HZ);
-		if (ret <= 0) {
+		if (time_left == 0) {
 			ret = -ETIMEDOUT;
 			goto out_unlock;
 		}
-- 
2.17.1