netfilter: nf_conntrack: allow nf_ct_alloc_hashtable() to get highmem pages

netfilter: nf_conntrack: allow nf_ct_alloc_hashtable() to get highmem pages

commit 6b1686a71e3158d3c5f125260effce171cc7852b upstream.

commit ea781f197d6a8 (use SLAB_DESTROY_BY_RCU and get rid of call_rcu())
did a mistake in __vmalloc() call in nf_ct_alloc_hashtable().

I forgot to add __GFP_HIGHMEM, so pages were taken from LOWMEM only.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Andi Kleen <ak@linux.intel.com>