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=-16.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 6B113C83028 for ; Thu, 2 Sep 2021 16:34:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 50A4060698 for ; Thu, 2 Sep 2021 16:34:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346370AbhIBQfE (ORCPT ); Thu, 2 Sep 2021 12:35:04 -0400 Received: from mail.kernel.org ([198.145.29.99]:36180 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242414AbhIBQfD (ORCPT ); Thu, 2 Sep 2021 12:35:03 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 83320600CC; Thu, 2 Sep 2021 16:34:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1630600445; bh=I+UdrRBmYFaWK3oBwVCt9HxFGvt0IAgmwkIcUTzH7xM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=EYIycoiS5EF3FWRx/vNxubQ06zX8ZPKHRyGJTPNQq+7cwO6+yfdMCnmYnI6UNiPUE h9r2HTL+RdQEelKGYZjBkV1rQmaf1QL2LFl9wqnWD8qazN4dAfL9tea2QrFUIhdNzq ubCmcMX93xfR8O8fnm6xSVzA5paUUiuArWQGMaPs= Date: Thu, 2 Sep 2021 18:34:02 +0200 From: Greg KH To: Christian =?iso-8859-1?Q?K=F6nig?= Cc: Nirmoy Das , rafael@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/1] debugfs: use IS_ERR to check for error Message-ID: References: <20210902102917.2233-1-nirmoy.das@amd.com> <5ab7739d-15a4-2e84-0320-fee8d5df1e83@amd.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Sep 02, 2021 at 05:10:24PM +0200, Christian König wrote: > Am 02.09.21 um 14:20 schrieb Greg KH: > > On Thu, Sep 02, 2021 at 02:03:12PM +0200, Christian König wrote: > > > > > > Am 02.09.21 um 12:38 schrieb Greg KH: > > > > On Thu, Sep 02, 2021 at 12:29:17PM +0200, Nirmoy Das wrote: > > > > > debugfs_create_file() returns encoded error so > > > > > use IS_ERR for checking return value. > > > > > > > > > > References: https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgitlab.freedesktop.org%2Fdrm%2Famd%2F-%2Fissues%2F1686&data=04%7C01%7Cchristian.koenig%40amd.com%7Cffc1109aeb744082181b08d96e0c06db%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637661820207117289%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=6NDHX9sEhGF2jakVfUJ7Qurql6UAdNpFQZ6XvCjwz0E%3D&reserved=0 > > > > > Signed-off-by: Nirmoy Das > > > > > --- > > > > > fs/debugfs/inode.c | 2 +- > > > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > > > > > diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c > > > > > index 8129a430d789..2f117c57160d 100644 > > > > > --- a/fs/debugfs/inode.c > > > > > +++ b/fs/debugfs/inode.c > > > > > @@ -528,7 +528,7 @@ void debugfs_create_file_size(const char *name, umode_t mode, > > > > > { > > > > > struct dentry *de = debugfs_create_file(name, mode, parent, data, fops); > > > > > - if (de) > > > > > + if (!IS_ERR(de)) > > > > > d_inode(de)->i_size = file_size; > > > > > } > > > > > EXPORT_SYMBOL_GPL(debugfs_create_file_size); > > > > > -- > > > > > 2.32.0 > > > > > > > > > Ah, good catch, I'll queue this up after 5.15-rc1 is out, thanks! > > > Thinking more about this if I'm not completely mistaken > > > debugfs_create_file() returns -ENODEV when debugfs is disabled and NULL on > > > any other error. > > How can this function be called if debugfs is not enabled in the system > > configuration? This _is_ the debugfs core code. > > Well, that's what I meant. The original code is correct and Nirmoy's patch > here is breaking it. Ah, yes, sorry, you are right. This function can not return an error value, if something went wrong, the result will always be NULL. > Nirmoys other patch is for a driver and there the function can indeed return > both error code and NULL. You should never be checking this stuff in a caller anyway, so no, don't do it there either. thanks, greg k-h