From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io0-f198.google.com (mail-io0-f198.google.com [209.85.223.198]) by kanga.kvack.org (Postfix) with ESMTP id 8A0BC6B000D for ; Wed, 27 Jun 2018 22:11:04 -0400 (EDT) Received: by mail-io0-f198.google.com with SMTP id n18-v6so3095763iog.10 for ; Wed, 27 Jun 2018 19:11:04 -0700 (PDT) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id u6-v6sor2297027itd.0.2018.06.27.19.11.03 for (Google Transport Security); Wed, 27 Jun 2018 19:11:03 -0700 (PDT) MIME-Version: 1.0 References: <60052659-7b37-cb69-bf9f-1683caa46219@redhat.com> In-Reply-To: <60052659-7b37-cb69-bf9f-1683caa46219@redhat.com> From: Linus Torvalds Date: Wed, 27 Jun 2018 19:10:51 -0700 Message-ID: Subject: Re: [PATCH] mm: reject MAP_SHARED_VALIDATE without new flags Content-Type: text/plain; charset="UTF-8" Sender: owner-linux-mm@kvack.org List-ID: To: Eric Sandeen Cc: linux-fsdevel , linux-mm , Linux API , linux-xfs , linux-ext4@vger.kernel.org, "linux-nvdimm@lists.01.org" , Dan Williams , Jan Kara , Christoph Hellwig , zhibli@redhat.com On Wed, Jun 27, 2018 at 6:45 PM Eric Sandeen wrote: > > Thus the invalid flag combination of (MAP_SHARED|MAP_PRIVATE) now > passes without error, which is a regression. It's not a regression, it's just new behavior. "regression" doesn't mean "things changed". It means "something broke". What broke? Because if it's some manual page breakage, just fix the manual. That's what "new behavior" is all about. There is nothing that says that "MAP_SHARED_VALIDATE" can't work with just the legacy flags. Because I'd be worried about your patch breaking some actual new user of MAP_SHARED_VALIDATE. Because it's actual *users* of behavior we care about, not some test-suite or manual pages. Linus