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Date: Fri, 11 Mar 2016 14:10:18 -0800
Message-ID: <CA+8MBbKn5DU22RHPYR=vKWpKd1aBu4dm5p57R5U5WTb7KCpMVQ@mail.gmail.com>
Subject: Re: [PATCH v14] x86, mce: Add memcpy_mcsafe()
From: Tony Luck <tony.luck@gmail.com>
To: =?UTF-8?Q?Mika_Penttil=C3=A4?= <mika.penttila@nextfour.com>,
        Ingo Molnar <mingo@kernel.org>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Thomas Gleixner <tglx@linutronix.de>, Borislav Petkov <bp@alien8.de>,
        Andrew Morton <akpm@linux-foundation.org>,
        Tony Luck <tony.luck@gmail.com>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>,
        "H. Peter Anvin" <hpa@zytor.com>,
        Andy Lutomirski <luto@amacapital.net>,
        "Williams, Dan J" <dan.j.williams@intel.com>
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On Thu, Mar 10, 2016 at 11:37 AM, Luck, Tony <tony.luck@intel.com> wrote:
>> But you return 0 == false for success and 1 == true for failure.
>
> Aaargh!  -ETOOMUCHSHELLSCRIPTPROGRAMMING
>
> -Tony

Options to fix this:
1) Just change the comments in the code.
     This seems like it would confuse people as I thing most people
     would expect the "true" return to mean the copy succeeded.
2) Reverse the return values.
     Better that option 1 - but doesn't leave scope to return a count
     if some future user does want to know where the copy failed.
3) Change the return type back from "bool" to "int"
     0 == success, non-zero == fail (with option to put the non-copied
byte count in later).
4) Something else

-Tony