mm: vmalloc: introduce array allocation functions

mm: vmalloc: introduce array allocation functions

BugLink: https://bugs.launchpad.net/bugs/1987451
[ Upstream commit a8749a35c39903120ec421ef2525acc8e0daa55c ]

Linux has dozens of occurrences of vmalloc(array_size()) and
vzalloc(array_size()).  Allow to simplify the code by providing
vmalloc_array and vcalloc, as well as the underscored variants that let
the caller specify the GFP flags.

Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>