Re: [PATCH 1/4] mm: add new mmgrab() helper

[Peter Zijlstra]

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.