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;
MIME-Version: 1.0
References: <20200114200846.29434-1-vgupta@synopsys.com> <20200114200846.29434-2-vgupta@synopsys.com>
 <CAK8P3a3W0eLK+qypnPwq=PdcF7+ey8OZEhmOoA6Bg7hMGm5hqQ@mail.gmail.com> <6eb7587b-c3bc-691d-9d27-d4e687114a42@synopsys.com>
In-Reply-To: <6eb7587b-c3bc-691d-9d27-d4e687114a42@synopsys.com>
From:   Arnd Bergmann <arnd@arndb.de>
Date:   Thu, 16 Jan 2020 12:43:39 +0100
Message-ID: <CAK8P3a398-ojtETr9A7YsGTHBnmqyiykcC0YmHQSL5Cw1jy=Ew@mail.gmail.com>
Subject: Re: [RFC 1/4] asm-generic/uaccess: don't define inline functions if
 noinline lib/* in use
To:     Vineet Gupta <Vineet.Gupta1@synopsys.com>
Cc:     Khalid Aziz <khalid.aziz@oracle.com>,
        Andrey Konovalov <andreyknvl@google.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Christian Brauner <christian.brauner@ubuntu.com>,
        Kees Cook <keescook@chromium.org>,
        Ingo Molnar <mingo@kernel.org>,
        Aleksa Sarai <cyphar@cyphar.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        "open list:SYNOPSYS ARC ARCHITECTURE" 
        <linux-snps-arc@lists.infradead.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        linux-arch <linux-arch@vger.kernel.org>
Content-Type: text/plain; charset="UTF-8"
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Thu, Jan 16, 2020 at 12:02 AM Vineet Gupta
<Vineet.Gupta1@synopsys.com> wrote:
> On 1/14/20 12:57 PM, Arnd Bergmann wrote:
> > On Tue, Jan 14, 2020 at 9:08 PM Vineet Gupta <Vineet.Gupta1@synopsys.com> wrote:
> >> There are 2 generic varaints of strncpy_from_user() / strnlen_user()
> >>  (1). inline version in asm-generic/uaccess.h
> >>  (2). optimized word-at-a-time version in lib/*
> >>
> >> This patch disables #1 if #2 selected. This allows arches to continue
> >> reusing asm-generic/uaccess.h for rest of code
> >>
> >> This came up when switching ARC to generic word-at-a-time interface
> >>
> >> Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
> > This looks like a useful change, but I think we can do even better: It
> > seems that
> > there are no  callers of __strnlen_user or __strncpy_from_user  in the
> > kernel today, so these should not be defined either when the Kconfig symbols
> > are set. Also, I would suggest moving the 'extern' declaration for the two
> > functions into the #else branch of the conditional so it does not need to be
> > duplicated.
>
> Given where things seem to be heading, do u still want an updated patch for this
> or do u plan to ditch the inline version in short term anyways.

I'm trying to come up with a cleanup series now that I'll send you.
You can base on top of that if you like.

     Arnd