From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jia-Ju Bai Subject: [PATCH 1/2] staging: irda: Replace mdelay with usleep_range in stir421x_fw_upload Date: Wed, 11 Apr 2018 09:29:34 +0800 Message-ID: <1523410174-1553-1-git-send-email-baijiaju1990@gmail.com> Cc: netdev@vger.kernel.org, devel@driverdev.osuosl.org, linux-kernel@vger.kernel.org, Jia-Ju Bai To: samuel@sortiz.org, gregkh@linuxfoundation.org, davem@davemloft.net, johan@kernel.org, arvind.yadav.cs@gmail.com Return-path: Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org 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 --- 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..c6c8c2c 100644 --- a/drivers/staging/irda/drivers/irda-usb.c +++ b/drivers/staging/irda/drivers/irda-usb.c @@ -1050,7 +1050,7 @@ static int stir421x_fw_upload(struct irda_usb_cb *self, if (ret < 0) break; - mdelay(10); + usleep_range(10000, 11000); } kfree(patch_block); -- 1.9.1