2018-04-11 01:37:47

by Jia-Ju Bai

Subject: [PATCH 2/2] staging: irda: Replace mdelay with usleep_range in irda_usb_probe

irda_usb_probe() is never called in atomic context.

irda_usb_probe() is only set as ".probe" in struct usb_driver.

Despite never getting called from atomic context, irda_usb_probe()
calls mdelay() to busily wait.
This is not necessary and can be replaced with usleep_range() to
avoid busy waiting.

This is found by a static analysis tool named DCNS written by myself.
And I also manually check it.

Signed-off-by: Jia-Ju Bai <[email protected]>
---
drivers/staging/irda/drivers/irda-usb.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/staging/irda/drivers/irda-usb.c b/drivers/staging/irda/drivers/irda-usb.c
index 723e49b..6ff5b08 100644
--- a/drivers/staging/irda/drivers/irda-usb.c
+++ b/drivers/staging/irda/drivers/irda-usb.c
@@ -1710,7 +1710,7 @@ static int irda_usb_probe(struct usb_interface *intf,
pr_debug("usb_control_msg failed %d\n", ret);
goto err_out_3;
} else {
- mdelay(10);
+ usleep_range(10000, 11000);
}
}

--
1.9.1

2018-04-11 07:13:17

by Johan Hovold

Subject: Re: [PATCH 2/2] staging: irda: Replace mdelay with usleep_range in irda_usb_probe

On Wed, Apr 11, 2018 at 09:33:55AM +0800, Jia-Ju Bai wrote:
> irda_usb_probe() is never called in atomic context.
>
> irda_usb_probe() is only set as ".probe" in struct usb_driver.
>
> Despite never getting called from atomic context, irda_usb_probe()
> calls mdelay() to busily wait.
> This is not necessary and can be replaced with usleep_range() to
> avoid busy waiting.
>
> This is found by a static analysis tool named DCNS written by myself.
> And I also manually check it.
>
> Signed-off-by: Jia-Ju Bai <[email protected]>

Reviewed-by: Johan Hovold <[email protected]>