mm/hugetlb: remove gigantic page support for HIGHMEM

This reverts ee8f248 ("hugetlb: add phys addr to struct
huge_bootmem_page").

At one time powerpc used this field and supporting code.  However that
was removed with commit 79cc38d ("powerpc/mm/hugetlb: Add support
for reserving gigantic huge pages via kernel command line").

There are no users of this field and supporting code, so remove it.

Link: http://lkml.kernel.org/r/20180711195913.1294-1-mike.kravetz@oracle.com
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Cannon Matthews <cannonmatthews@google.com>
Cc: Becky Bruce <beckyb@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/hugetlb.h

@@ -348,9 +348,6 @@ struct hstate {
 struct huge_bootmem_page {
 	struct list_head list;
 	struct hstate *hstate;
-#ifdef CONFIG_HIGHMEM
-	phys_addr_t phys;
-#endif
 };
 
 struct page *alloc_huge_page(struct vm_area_struct *vma,

mm/hugetlb.c

@@ -2139,16 +2139,9 @@ static void __init gather_bootmem_prealloc(void)
 	struct huge_bootmem_page *m;
 
 	list_for_each_entry(m, &huge_boot_pages, list) {
+		struct page *page = virt_to_page(m);
 		struct hstate *h = m->hstate;
-		struct page *page;
 
-#ifdef CONFIG_HIGHMEM
-		page = pfn_to_page(m->phys >> PAGE_SHIFT);
-		memblock_free_late(__pa(m),
-				   sizeof(struct huge_bootmem_page));
-#else
-		page = virt_to_page(m);
-#endif
 		WARN_ON(page_count(page) != 1);
 		prep_compound_huge_page(page, h->order);
 		WARN_ON(PageReserved(page));