From: Xin Long <lucien.xin@gmail.com>
Date: Wed,  5 Dec 2018 14:49:40 +0800

This patch is to separate the base data memory from struct flex_array and
save it into a page. With this change, total_nr_elements of a flex_array
can grow or shrink without having the old element's memory changed when
the new size of the flex_arry crosses FLEX_ARRAY_BASE_SIZE, which will
be added in the next patch.

Suggested-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>

This needs to be reviewed by the flex array hackers and lkml.

It can't just get reviewed on netdev alone.