tree a93311357f7ac4589cffd2445be90bdacdd753f6
parent 4c1c7740335b40b51cce9303e68d4b3f3a8ac102
author Michal Hocko <mhocko@suse.com> 1500377163 +0200
committer Michal Hocko <mhocko@suse.com> 1500392725 +0200

mm, arch: unify vmemmap_populate altmap handling

vmem_altmap allows vmemmap_populate to allocate memmap (struct page
array) from an alternative allocator rather than bootmem resp.
kmalloc. Only x86 currently supports altmap handling, most likely
because only nvdim code uses this mechanism currently and the code
depends on ZONE_DEVICE which is present only for x86_64. This will
change in follow up changes so we would like other architectures
to support it as well.

Provide vmemmap_populate generic implementation which simply resolves
altmap and then call into arch specific __vmemmap_populate.
Architectures then only need to use __vmemmap_alloc_block_buf to
allocate the memmap. vmemmap_free then needs to call vmem_altmap_free
if there is any altmap associated with the address.

This patch shouldn't introduce any functional changes because
to_vmem_altmap always returns NULL on !x86_x64.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-ia64@vger.kernel.org
Cc: x86@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>