[RFC 1/7] powerpc/mm: Make vmemmap_populate accommodate ZONE_DEVICE memory

[Anshuman Khandual <khandual@linux.vnet.ibm.com>]

Change the vmemmap_populate function to detect device memory through
to_vmemmap_altmap and then call generic the __vmmemap_alloc_block_buf
function instead of vmemmap_alloc_block as the earlier can allocate
physical memory from the device range instead of the system RAM.

Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>
---
 arch/powerpc/mm/init_64.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c
index ba65566..db73708 100644
--- a/arch/powerpc/mm/init_64.c
+++ b/arch/powerpc/mm/init_64.c
@@ -42,6 +42,7 @@
 #include <linux/memblock.h>
 #include <linux/hugetlb.h>
 #include <linux/slab.h>
+#include <linux/memremap.h>
 
 #include <asm/pgalloc.h>
 #include <asm/page.h>
@@ -312,6 +313,7 @@ static __meminit void vmemmap_list_populate(unsigned long phys,
 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node)
 {
 	unsigned long page_size = 1 << mmu_psize_defs[mmu_vmemmap_psize].shift;
+	unsigned long orig = start;
 
 	/* Align to the page size of the linear mapping. */
 	start = _ALIGN_DOWN(start, page_size);
@@ -319,13 +321,15 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node)
 	pr_debug("vmemmap_populate %lx..%lx, node %d\n", start, end, node);
 
 	for (; start < end; start += page_size) {
+		struct vmem_altmap *altmap;
 		void *p;
 		int rc;
 
 		if (vmemmap_populated(start, page_size))
 			continue;
 
-		p = vmemmap_alloc_block(page_size, node);
+		altmap = to_vmem_altmap((unsigned long) orig);
+		p = __vmemmap_alloc_block_buf(page_size, node, altmap);
 		if (!p)
 			return -ENOMEM;
 
-- 
1.8.3.1