mm/um: use free_highmem_page() to free highmem pages into buddy system

Use helper function free_highmem_page() to free highmem pages into
the buddy system.
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/um/kernel/mem.c

@@ -42,17 +42,12 @@ static unsigned long brk_end;
 static void setup_highmem(unsigned long highmem_start,
 			  unsigned long highmem_len)
 {
-	struct page *page;
 	unsigned long highmem_pfn;
 	int i;
 
 	highmem_pfn = __pa(highmem_start) >> PAGE_SHIFT;
-	for (i = 0; i < highmem_len >> PAGE_SHIFT; i++) {
-		page = &mem_map[highmem_pfn + i];
-		ClearPageReserved(page);
-		init_page_count(page);
-		__free_page(page);
-	}
+	for (i = 0; i < highmem_len >> PAGE_SHIFT; i++)
+		free_highmem_page(&mem_map[highmem_pfn + i]);
 }
 #endif
 
@@ -73,18 +68,13 @@ void __init mem_init(void)
 	totalram_pages = free_all_bootmem();
 	max_low_pfn = totalram_pages;
 #ifdef CONFIG_HIGHMEM
-	totalhigh_pages = highmem >> PAGE_SHIFT;
-	totalram_pages += totalhigh_pages;
+	setup_highmem(end_iomem, highmem);
 #endif
 	num_physpages = totalram_pages;
 	max_pfn = totalram_pages;
 	printk(KERN_INFO "Memory: %luk available\n",
 	       nr_free_pages() << (PAGE_SHIFT-10));
 	kmalloc_ok = 1;
-
-#ifdef CONFIG_HIGHMEM
-	setup_highmem(end_iomem, highmem);
-#endif
 }
 
 /*