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[209.132.180.67]) by mx.google.com with ESMTP id f1si7991056pgi.432.2019.05.31.16.37.47; Fri, 31 May 2019 16:38:03 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726880AbfEaXgn (ORCPT + 99 others); Fri, 31 May 2019 19:36:43 -0400 Received: from mail-pg1-f196.google.com ([209.85.215.196]:43227 "EHLO mail-pg1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726643AbfEaXgn (ORCPT ); Fri, 31 May 2019 19:36:43 -0400 Received: by mail-pg1-f196.google.com with SMTP id f25so4849373pgv.10 for ; Fri, 31 May 2019 16:36:42 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:subject:in-reply-to:cc:from:to:message-id :mime-version:content-transfer-encoding; bh=ETJ6ykBl1LYGxegwTN6YGSCsMcqD6BFzZek270Zuebk=; b=IgmLv/Xs176W/ck+Ol/au9faCGFs0O+oyMm8rtkZifVmVhiECGa40A0IJIehQKXM5G kAxZCqVTvwzjJOGRg93FzjNN+JHLnNEPDldPdrv5FoW04RAPwD5Tw+bljOL7e3dDXe56 tiTpfIGL6tY9GTs+7Wq++1vsYBfcFZXywnCMhWxv7iZ9wZJsAThPmhWwc2/8OYPmY394 sd8vEIyqt9MbO35cxHpIdhKnwfC/zBT/F32jeQUHSi7axGAWuQrGVu0O6s4Xy3tpLX0o R40H6BTbppvstsx+QDZnFsMZKvJ+8w+qM5ETSc4/McFUh/tElMunTSKjP1WWmnPJkYDQ cSWQ== X-Gm-Message-State: APjAAAW+m6I57JKLlP3JLIcEsz2/NTyJmNUIH3FFTJzalnHJuz1P19jV z5Y8ZbLnhGs4wEC7unjmPekvMA== X-Received: by 2002:a17:90a:207:: with SMTP id c7mr12479237pjc.94.1559345802001; Fri, 31 May 2019 16:36:42 -0700 (PDT) Received: from localhost ([12.206.222.5]) by smtp.gmail.com with ESMTPSA id t187sm7656787pfb.64.2019.05.31.16.36.41 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Fri, 31 May 2019 16:36:41 -0700 (PDT) Date: Fri, 31 May 2019 16:36:41 -0700 (PDT) X-Google-Original-Date: Fri, 31 May 2019 16:23:50 PDT (-0700) Subject: Re: [PATCH 2/5] Add fchmodat4(), a new syscall In-Reply-To: CC: viro@zeniv.linux.org.uk, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org, linux-arch@vger.kernel.org, x86@kernel.org, luto@kernel.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, hpa@zytor.com From: Palmer Dabbelt To: Arnd Bergmann Message-ID: Mime-Version: 1.0 (MHng) Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 31 May 2019 12:51:00 PDT (-0700), Arnd Bergmann wrote: > On Fri, May 31, 2019 at 9:23 PM Palmer Dabbelt wrote: >> >> man 3p says that fchmodat() takes a flags argument, but the Linux >> syscall does not. There doesn't appear to be a good userspace >> workaround for this issue but the implementation in the kernel is pretty >> straight-forward. The specific use case where the missing flags came up >> was WRT a fuse filesystem implemenation, but the functionality is pretty >> generic so I'm assuming there would be other use cases. >> >> Signed-off-by: Palmer Dabbelt >> --- >> fs/open.c | 21 +++++++++++++++++++-- >> include/linux/syscalls.h | 5 +++++ >> 2 files changed, 24 insertions(+), 2 deletions(-) >> >> diff --git a/fs/open.c b/fs/open.c >> index a00350018a47..cfad7684e8d3 100644 >> --- a/fs/open.c >> +++ b/fs/open.c >> @@ -568,11 +568,17 @@ SYSCALL_DEFINE2(fchmod, unsigned int, fd, umode_t, mode) >> return ksys_fchmod(fd, mode); >> } >> >> -int do_fchmodat(int dfd, const char __user *filename, umode_t mode) >> +int do_fchmodat4(int dfd, const char __user *filename, umode_t mode, int flags) > ... >> + >> +int do_fchmodat(int dfd, const char __user *filename, umode_t mode) >> +{ >> + return do_fchmodat4(dfd, filename, mode, 0); >> +} >> + > > There is only one external caller of do_fchmodat(), so just change that > to pass the extra argument here, and keep a single do_fchmodat() > function used by the sys_fchmod(), sys_fchmod4(), sys_chmod() > and ksys_chmod(). OK, I'll roll that up into a v2.