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=-17.2 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, URIBL_BLOCKED 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 573E5C433F5 for ; Tue, 21 Sep 2021 07:03:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2E56B61183 for ; Tue, 21 Sep 2021 07:03:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230054AbhIUHFQ (ORCPT ); Tue, 21 Sep 2021 03:05:16 -0400 Received: from mail.kernel.org ([198.145.29.99]:50896 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230020AbhIUHFP (ORCPT ); Tue, 21 Sep 2021 03:05:15 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 697E961183; Tue, 21 Sep 2021 07:03:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1632207827; bh=mQuKWQo9X6JaJZ7Qid4y074fGnCtlx3T1Uh750N/tEs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=yhtWj7GHyb/Hq3YLZXfZPlNogmK+oV2YZqLjFwHz5QEeOVIOQ24hElvvY+55X6RAp k+uA+r3rxqR0ke0ZpaUG1iog7FtXXJHHGNx9/beGQCdcn2wpq8K3BiGMMkbFWZpc8j S+rOuecgOJYh5v3k5btl7iI0wnWevUXglHwvk0e0= Date: Tue, 21 Sep 2021 09:03:44 +0200 From: Greg KH To: Christian =?iso-8859-1?Q?K=F6nig?= Cc: "Das, Nirmoy" , rafael@kernel.org, linux-kernel@vger.kernel.org, Nirmoy Das 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 Fri, Sep 03, 2021 at 08:27:34AM +0200, Christian König wrote: > Am 02.09.21 um 19:01 schrieb Das, Nirmoy: > > > > On 9/2/2021 6:34 PM, Greg KH wrote: > > > 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%7Cnirmoy.das%40amd.com%7C7a1f1095c0d64416576c08d96e2f7b38%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637661973378236086%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=g9BQRJG8gvjGFq6oj5vk9PCemQ39U19CLmkMNHVUafg%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. > > > > > > I just realized that we don't return NULL on error anymore: > > > > commit ff9fb72bc07705c00795ca48631f7fffe24d2c6b > > Author: Greg Kroah-Hartman > > Date:   Wed Jan 23 11:28:14 2019 +0100 > > > >     debugfs: return error values, not NULL > > > > > > and the current doc also says "If an error occurs, ERR_PTR(-ERROR) will > > be returned." > > > > If I am not missing anything, this patch should be fine. > > Ah! Yes, now that makes sense. > > Looks like that my memory and the documentation under > https://www.kernel.org/doc/htmldocs/filesystems/API-debugfs-create-file.html > is outdated. > > I can update my memory, but I have no idea where this documentation comes > from and how to fix it. I do not know how that is created either, it looks very old. This link should always be used instead: https://www.kernel.org/doc/html/latest/index.html thanks, greg k-h