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[209.132.180.67]) by mx.google.com with ESMTP id d5si7498012pla.376.2019.05.31.12.53.28; Fri, 31 May 2019 12:53:44 -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 S1727416AbfEaTvS (ORCPT + 99 others); Fri, 31 May 2019 15:51:18 -0400 Received: from mail-qt1-f196.google.com ([209.85.160.196]:43802 "EHLO mail-qt1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727199AbfEaTvR (ORCPT ); Fri, 31 May 2019 15:51:17 -0400 Received: by mail-qt1-f196.google.com with SMTP id z24so2332567qtj.10; Fri, 31 May 2019 12:51:17 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=Xsy7KltLXxbW0BgIu9F6NiZrWo9L3TAjqu6dUK3uAPQ=; b=HKiKcAe9NTvT7jlqURubrv6AeE+r3LE2+ofsKjOLjlU0ld0Pi3r+5W07WAc3VTxYm/ 5wrIZtFRKGTy2rH60ru5gu6eOl/YzHfcZSENVMsY8hGuobbDe4O1sp/TxLr5Xtsr4Dl0 dwdKN9ROAl13qXJcOMT007U4IWvdTWmffPs1e/NuDc2RCbGRUSJHKyvb2Ua41NmLi8G1 EhPapRhPY4RVQXaXXLgkI1YZG/BcMmh5QvS0t30z3V25fLVbsq6/fspHUsKpvJ5a4hme +UQJfWQiDpAbWQZ3HSdJDulMjntf/kxRd4eh+RUPfIwyjA0FaD9D0kqAasz8h5U5CYIq Ph5g== X-Gm-Message-State: APjAAAUm+OEZ/7YxeQJx+zOKF7n1s+UtucC9RQHHqU7lyIRYoURhthq4 lFcldEooRRjhXGvtLlCoJhz/ZuU5uw2YIIyBzTU= X-Received: by 2002:a0c:e78b:: with SMTP id x11mr6666549qvn.93.1559332276507; Fri, 31 May 2019 12:51:16 -0700 (PDT) MIME-Version: 1.0 References: <20190531191204.4044-1-palmer@sifive.com> <20190531191204.4044-3-palmer@sifive.com> In-Reply-To: <20190531191204.4044-3-palmer@sifive.com> From: Arnd Bergmann Date: Fri, 31 May 2019 21:51:00 +0200 Message-ID: Subject: Re: [PATCH 2/5] Add fchmodat4(), a new syscall To: Palmer Dabbelt Cc: Al Viro , Linux Kernel Mailing List , Linux FS-devel Mailing List , Linux API , linux-arch , "the arch/x86 maintainers" , Andy Lutomirski , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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(). Arnd