[PATCH] [RFC] CMA: clear buffer-head lru before page migration

[Gioh Kim]

Hi,

For page migration of CMA, buffer-heads of lru should be dropped.
Please refer to https://lkml.org/lkml/2014/6/23/932 for the detail.

I'm attaching a patch to drop all buffer-head on lru with invalidate_bh_lrus.
Please look into this. Thanks

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