From mboxrd@z Thu Jan 1 00:00:00 1970 From: Johan Hovold Subject: Re: [PATCH 1/2] staging: irda: Replace mdelay with usleep_range in stir421x_fw_upload Date: Wed, 11 Apr 2018 09:07:42 +0200 Message-ID: <20180411070742.GE10795@localhost> References: <1523410174-1553-1-git-send-email-baijiaju1990@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: devel@driverdev.osuosl.org, samuel@sortiz.org, gregkh@linuxfoundation.org, johan@kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, arvind.yadav.cs@gmail.com, davem@davemloft.net To: Jia-Ju Bai Return-path: Content-Disposition: inline In-Reply-To: <1523410174-1553-1-git-send-email-baijiaju1990@gmail.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: driverdev-devel-bounces@linuxdriverproject.org Sender: "devel" List-Id: netdev.vger.kernel.org On Wed, Apr 11, 2018 at 09:29:34AM +0800, Jia-Ju Bai wrote: > stir421x_fw_upload() is never called in atomic context. > > The call chain ending up at stir421x_fw_upload() is: > [1] stir421x_fw_upload() <- stir421x_patch_device() <- irda_usb_probe() > > irda_usb_probe() is set as ".probe" in struct usb_driver. > This function is not called in atomic context. > > Despite never getting called from atomic context, stir421x_fw_upload() > 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 This all looks good (also note the call to usb_control_msg(), which may sleep, just above the mdelay()). Reviewed-by: Johan Hovold Thanks, Johan