datapath: convert to kvmalloc

datapath: convert to kvmalloc

Upstream commit:
    commit ee9c5e67557f9663b27946ba1d3813fb1924b1fe
    Author: Kent Overstreet <kent.overstreet@gmail.com>
    Date:   Mon Mar 11 23:31:02 2019 -0700

    openvswitch: convert to kvmalloc

    Patch series "generic radix trees; drop flex arrays".

    This patch (of 7):

    There was no real need for this code to be using flexarrays, it's just
    implementing a hash table - ideally it would be using rhashtables, but
    that conversion would be significantly more complicated.

Link: http://lkml.kernel.org/r/20181217131929.11727-2-kent.overstreet@gmail.com
    Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
    Reviewed-by: Matthew Wilcox <willy@infradead.org>
    Cc: Pravin B Shelar <pshelar@ovn.org>
    Cc: Alexey Dobriyan <adobriyan@gmail.com>
    Cc: Al Viro <viro@zeniv.linux.org.uk>
    Cc: Dave Hansen <dave.hansen@intel.com>
    Cc: Eric Paris <eparis@parisplace.org>
    Cc: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
    Cc: Neil Horman <nhorman@tuxdriver.com>
    Cc: Paul Moore <paul@paul-moore.com>
    Cc: Shaohua Li <shli@kernel.org>
    Cc: Stephen Smalley <sds@tycho.nsa.gov>
    Cc: Vlad Yasevich <vyasevich@gmail.com>
    Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
    Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Reviewed-by: Yifeng Sun <pkusunyifeng@gmail.com>
Signed-off-by: Greg Rose <gvrose8192@gmail.com>
Signed-off-by: Ben Pfaff <blp@ovn.org>