linux-kernel - [PATCH 5/6] staging: rtl8192u: Replace mdelay with usleep_range in rtl8192_usb

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Date:   Tue, 10 Apr 2018 20:25:09 +0800
From:   Jia-Ju Bai <baijiaju1990@...il.com>
To:     gregkh@...uxfoundation.org, szekelyszilv@...il.com,
        shreeya.patel23498@...il.com, colin.king@...onical.com
Cc:     devel@...verdev.osuosl.org, linux-kernel@...r.kernel.org,
        Jia-Ju Bai <baijiaju1990@...il.com>
Subject: [PATCH 5/6] staging: rtl8192u: Replace mdelay with usleep_range in rtl8192_usb_disconnect

rtl8192_usb_disconnect() is never called in atomic context.

rtl8192_usb_disconnect() is only set as ".disconnect" in 
struct usb_driver.

Despite never getting called from atomic context, 
rtl8192_usb_disconnect() 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/rtl8192u/r8192U_core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/staging/rtl8192u/r8192U_core.c b/drivers/staging/rtl8192u/r8192U_core.c
index 46b3f19..04ed34a 100644
--- a/drivers/staging/rtl8192u/r8192U_core.c
+++ b/drivers/staging/rtl8192u/r8192U_core.c
@@ -5033,7 +5033,7 @@ static void rtl8192_usb_disconnect(struct usb_interface *intf)
 		kfree(priv->pFirmware);
 		priv->pFirmware = NULL;
 		rtl8192_usb_deleteendpoints(dev);
-		mdelay(10);
+		usleep_range(10000, 11000);
 	}
 	free_ieee80211(dev);
 	RT_TRACE(COMP_DOWN, "wlan driver removed\n");
-- 
1.9.1