2022-04-12 08:53:30

by Miaoqian Lin

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 <[email protected]>
---
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

2022-06-29 05:56:54

by Dmitry Torokhov

Subject: Re: [PATCH] Input: exc3000 - Fix return value check of wait_for_completion_timeout

On Mon, Apr 11, 2022 at 10:58:23AM +0000, Miaoqian Lin wrote:
> 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 <[email protected]>

Applied, thank you.

--
Dmitry