linux-kernel - [PATCH 2/2] staging: irda: Replace mdelay with usleep_range in irda_usb

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Date:   Wed, 11 Apr 2018 09:33:55 +0800
From:   Jia-Ju Bai <baijiaju1990@...il.com>
To:     samuel@...tiz.org, gregkh@...uxfoundation.org, davem@...emloft.net,
        johan@...nel.org, arvind.yadav.cs@...il.com
Cc:     netdev@...r.kernel.org, devel@...verdev.osuosl.org,
        linux-kernel@...r.kernel.org, Jia-Ju Bai <baijiaju1990@...il.com>
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 <baijiaju1990@...il.com>
---
 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