From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY, USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1043BC64E90 for ; Tue, 1 Dec 2020 14:39:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B73A02076C for ; Tue, 1 Dec 2020 14:39:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391613AbgLAOjd (ORCPT ); Tue, 1 Dec 2020 09:39:33 -0500 Received: from bhuna.collabora.co.uk ([46.235.227.227]:40354 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391368AbgLAOjd (ORCPT ); Tue, 1 Dec 2020 09:39:33 -0500 Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: koike) with ESMTPSA id 1E32E1F44B45 Subject: Re: [PATCH] media: rockchip: rkisp1: remove some dead code To: Dan Carpenter Cc: Dafna Hirschfeld , Mauro Carvalho Chehab , Heiko Stuebner , linux-media@vger.kernel.org, linux-rockchip@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org References: <20201201142754.GI2767@kadam> From: Helen Koike Message-ID: Date: Tue, 1 Dec 2020 11:38:33 -0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.4.0 MIME-Version: 1.0 In-Reply-To: <20201201142754.GI2767@kadam> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org Hi Dan, On 12/1/20 11:27 AM, Dan Carpenter wrote: > On Mon, Nov 30, 2020 at 11:20:05AM -0300, Helen Koike wrote: >> Hi Dan, >> >> Thank you for your patch. >> >> On 11/30/20 9:53 AM, Dan Carpenter wrote: >>> The debugfs_create_dir() function never returns NULLs. It's not supposed >>> to checked for errors in the normal case and there is no need to check >>> in this function so let's just delete this dead code. >>> >>> Signed-off-by: Dan Carpenter >>> --- >>> drivers/media/platform/rockchip/rkisp1/rkisp1-dev.c | 4 ---- >>> 1 file changed, 4 deletions(-) >>> >>> diff --git a/drivers/media/platform/rockchip/rkisp1/rkisp1-dev.c b/drivers/media/platform/rockchip/rkisp1/rkisp1-dev.c >>> index 9af137e4967f..68da1eed753d 100644 >>> --- a/drivers/media/platform/rockchip/rkisp1/rkisp1-dev.c >>> +++ b/drivers/media/platform/rockchip/rkisp1/rkisp1-dev.c >>> @@ -430,10 +430,6 @@ static void rkisp1_debug_init(struct rkisp1_device *rkisp1) >>> struct rkisp1_debug *debug = &rkisp1->debug; >>> >>> debug->debugfs_dir = debugfs_create_dir(RKISP1_DRIVER_NAME, NULL); >>> - if (!debug->debugfs_dir) { >>> - dev_dbg(rkisp1->dev, "failed to create debugfs directory\n"); >>> - return; >>> - } >> >> I was taking a look at the debugfs_create_dir() code, and I saw it can >> return ERR_PTR(), so ideally we should check for errors with IS_ERR() / PTR_ERR(). > > Debugfs functions aren't meant to be error checked in the normal case. > There are some drivers which dereference the dentry pointer so those > need to check it but that's not very common and isn't the case here. right, I just saw the functions in inode.c already checks the parent with IS_ERR(). the debugfs_create_*() function calls start_creating() which already checks the parent. ok, fair enough, I'll ack v2. Regards, Helen > > I'm really sure this must be documented somewhere but I can't find it > at all. :P But look at commit 057e212eae72 ("media: usb: uvc: no need > to check return value of debugfs_create functions") for example. > > regards, > dan carpenter >