Date: Fri, 16 Dec 2016 10:56:24 +0100
From: Peter Zijlstra <peterz@infradead.org>
To: Vegard Nossum <vegard.nossum@oracle.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        Rik van Riel <riel@redhat.com>,
        Matthew Wilcox <mawilcox@microsoft.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Michal Hocko <mhocko@suse.com>, Al Viro <viro@zeniv.linux.org.uk>,
        Ingo Molnar <mingo@kernel.org>,
        Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH 1/4] mm: add new mmgrab() helper
Message-ID: <20161216095624.GR3107@twins.programming.kicks-ass.net>
References: <20161216082202.21044-1-vegard.nossum@oracle.com>
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On Fri, Dec 16, 2016 at 09:21:59AM +0100, Vegard Nossum wrote:
> Apart from adding the helper function itself, the rest of the kernel is
> converted mechanically using:
> 
>   git grep -l 'atomic_inc.*mm_count' | xargs sed -i 's/atomic_inc(&\(.*\)->mm_count);/mmgrab\(\1\);/'
>   git grep -l 'atomic_inc.*mm_count' | xargs sed -i 's/atomic_inc(&\(.*\)\.mm_count);/mmgrab\(\&\1\);/'
> 
> This is needed for a later patch that hooks into the helper, but might be
> a worthwhile cleanup on its own.

Given the desire to replace all refcounting with a specific refcount
type, this seems to make sense.

FYI: http://www.openwall.com/lists/kernel-hardening/2016/12/07/8

But I must say mmget() vs mmgrab() is a wee bit confusing.