From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753884AbeDJNox (ORCPT ); Tue, 10 Apr 2018 09:44:53 -0400 Received: from mail-pf0-f194.google.com ([209.85.192.194]:39876 "EHLO mail-pf0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753782AbeDJNou (ORCPT ); Tue, 10 Apr 2018 09:44:50 -0400 X-Google-Smtp-Source: AIpwx4/tbpYZDt0DE4FhKJU3kLyPIuQqQ3Y5GUAbHB7wUvkyfwmvkuvktXgm8e/70GLMBEvncPNbMg== From: Jia-Ju Bai To: kvalo@codeaurora.org, davem@davemloft.net, gustavo@embeddedor.com, mingo@kernel.org, dhowells@redhat.com, johannes.berg@intel.com Cc: linux-wireless@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Jia-Ju Bai Subject: [PATCH] net: wireless: cisco: airo: Replace mdelay with usleep_range in flashgchar Date: Tue, 10 Apr 2018 21:44:41 +0800 Message-Id: <1523367881-32058-1-git-send-email-baijiaju1990@gmail.com> X-Mailer: git-send-email 1.9.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org flashgchar() is never called in atomic context. flashgchar() is only called by flashcard(). flashcard() calls copy_from_user() and kmalloc(GFP_KERNEL), which indicates this function is not called in atomic context. Despite never getting called from atomic context, flashgchar() 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 --- drivers/net/wireless/cisco/airo.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/wireless/cisco/airo.c b/drivers/net/wireless/cisco/airo.c index 54201c0..45747b7 100644 --- a/drivers/net/wireless/cisco/airo.c +++ b/drivers/net/wireless/cisco/airo.c @@ -8106,7 +8106,7 @@ static int flashgchar(struct airo_info *ai,int matchbyte,int dwelltime){ if(dwelltime && !(0x8000 & rchar)){ dwelltime -= 10; - mdelay(10); + usleep_range(10000, 11000); continue; } rbyte = 0xff & rchar; -- 1.9.1