[PATCH 5.15 068/244] Input: exc3000 - fix return value check of wait_for_completion_timeout

Greg Kroah-Hartman
2022-08-23T09:53:03Z

From: Miaoqian Lin <linmq006@gmail.com>

commit 6bb7144c3fa16a5efb54a8e2aff1817b4168018e upstream.

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@gmail.com>
Link: https://lore.kernel.org/r/20220411105828.22140-1-linmq006@gmail.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/input/touchscreen/exc3000.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

--- a/drivers/input/touchscreen/exc3000.c
+++ b/drivers/input/touchscreen/exc3000.c
@@ -220,6 +220,7 @@ static int exc3000_vendor_data_request(s
{
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(s
goto out_unlock;

if (response) {
- ret = wait_for_completion_timeout(&data->wait_event,
- timeout * HZ);
- if (ret <= 0) {
+ time_left = wait_for_completion_timeout(&data->wait_event,
+ timeout * HZ);
+ if (time_left == 0) {
ret = -ETIMEDOUT;
goto out_unlock;
}