Date: Fri, 17 Jan 2014 21:09:23 +0100
From: Oleg Nesterov <oleg@redhat.com>
To: Alex Thorlton <athorlton@sgi.com>
Cc: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Rik van Riel <riel@redhat.com>,
        Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>,
        "Eric W. Biederman" <ebiederm@xmission.com>,
        Andy Lutomirski <luto@amacapital.net>,
        Al Viro <viro@zeniv.linux.org.uk>, Kees Cook <keescook@chromium.org>,
        Andrea Arcangeli <aarcange@redhat.com>
Subject: Re: [RFC PATCHv2 1/2] Add mm flag to control THP
Message-ID: <20140117200923.GA15234@redhat.com>
References: <1bc8f911363af956b37d8ea415d734f3191f1c78.1389905087.git.athorlton@sgi.com>
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On 01/16, Alex Thorlton wrote:
>
> +	case PR_GET_THP_DISABLE:
> +		error = put_user(test_bit(MMF_THP_DISABLE,
> +				 &me->mm->flags),
> +				 (int __user *) arg2);
> +		break;

Do we really want put_user?

	error = test_bit(MMF_THP_DISABLE);

can work too and looks simpler (and to me simpler to use in userspace).

PR_GET_DUMPABLE works this way.

Oleg.

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