Date: Thu, 30 Mar 2017 15:48:48 +0100
From: Al Viro <viro@ZenIV.linux.org.uk>
To: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Richard Henderson <rth@twiddle.net>,
        Russell King <linux@armlinux.org.uk>,
        Will Deacon <will.deacon@arm.com>,
        Haavard Skinnemoen <hskinnemoen@gmail.com>,
        Vineet Gupta <vgupta@synopsys.com>, Steven Miao <realmz6@gmail.com>,
        Jesper Nilsson <jesper.nilsson@axis.com>,
        Mark Salter <msalter@redhat.com>,
        Yoshinori Sato <ysato@users.sourceforge.jp>,
        Richard Kuo <rkuo@codeaurora.org>, Tony Luck <tony.luck@intel.com>,
        Geert Uytterhoeven <geert@linux-m68k.org>,
        James Hogan <james.hogan@imgtec.com>, Michal Simek <monstr@monstr.eu>,
        David Howells <dhowells@redhat.com>, Ley Foon Tan <lftan@altera.com>,
        Jonas Bonn <jonas@southpole.se>, Helge Deller <deller@gmx.de>,
        Ralf Baechle <ralf@linux-mips.org>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Chen Liqin <liqin.linux@gmail.com>,
        "David S. Miller" <davem@davemloft.net>,
        Chris Metcalf <cmetcalf@mellanox.com>,
        Richard Weinberger <richard@nod.at>, Guan Xuetao <gxt@mprc.pku.edu.cn>,
        Thomas Gleixner <tglx@linutronix.de>, Chris Zankel <chris@zankel.net>
Subject: Re: [RFC][CFT][PATCHSET v1] uaccess unification
Message-ID: <20170330144847.GN29622@ZenIV.linux.org.uk>
References: <20170329055706.GH29622@ZenIV.linux.org.uk>
 <20170330143212.31353830@mschwideX1>
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On Thu, Mar 30, 2017 at 02:32:12PM +0200, Martin Schwidefsky wrote:
> On Wed, 29 Mar 2017 06:57:06 +0100
> Al Viro <viro@ZenIV.linux.org.uk> wrote:
> 
> > 	The patchset currently in vfs.git#work.uaccess is the result;
> > there's more work to do, but it takes care of a large part of the
> > problems.  About 2.8KLoc removed, a lot of cruft is gone and semantics
> > is hopefully in sync now.  All but two architectures (ia64 and metag)
> > had been switched to new mechanism; for these two I'm afraid that I'll
> > need serious help from maintainers.
> 
> I have tested the code in vfs.git#work.uaccess and in principle it works
> for s390. I found one bug which would return an incorrect result
> for copy_from_user if the access faults on the last page of the copy.
> In that case the new code would return 0 instead of the remaining bytes.
> 
> This patch snippet should fix it, please just merge it into commit
> "s390: get rid of zeroing, switch to RAW_COPY_USER"

Done.