x86: e820: Remove conditional early mapping in parse_e820_ext

This patch ensures that the memory passed from parse_setup_data() is
large enough to cover the complete data structure. That means that the
conditional mapping in parse_e820_ext() can go.

While here, I also attempt not to map two pages if the address is not
aligned to a page boundary.

Signed-off-by: Sebastian Andrzej Siewior <[e-mail]>
Signed-off-by: Dirk Brandewie <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
LKML-Reference: <[e-mail]>
Signed-off-by: Thomas Gleixner <[e-mail]>

arch/x86/include/asm/e820.h

···
 extern int e820_search_gap(unsigned long *gapstart, unsigned long *gapsize,
 			unsigned long start_addr, unsigned long long end_addr);
 struct setup_data;
-extern void parse_e820_ext(struct setup_data *data, unsigned long pa_data);
+extern void parse_e820_ext(struct setup_data *data);
 
 #if defined(CONFIG_X86_64) || \
 	(defined(CONFIG_X86_32) && defined(CONFIG_HIBERNATION))

arch/x86/kernel/e820.c

···
  * boot_params.e820_map, others are passed via SETUP_E820_EXT node of
  * linked list of struct setup_data, which is parsed here.
  */
-void __init parse_e820_ext(struct setup_data *sdata, unsigned long pa_data)
+void __init parse_e820_ext(struct setup_data *sdata)
 {
-	u32 map_len;
 	int entries;
 	struct e820entry *extmap;
 
 	entries = sdata->len / sizeof(struct e820entry);
-	map_len = sdata->len + sizeof(struct setup_data);
-	if (map_len > PAGE_SIZE)
-		sdata = early_ioremap(pa_data, map_len);
 	extmap = (struct e820entry *)(sdata->data);
 	__append_e820_map(extmap, entries);
 	sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
-	if (map_len > PAGE_SIZE)
-		early_iounmap(sdata, map_len);
 	printk(KERN_INFO "extended physical RAM map:\n");
 	e820_print_map("extended");
 }

arch/x86/kernel/setup.c

···
 		return;
 	pa_data = boot_params.hdr.setup_data;
 	while (pa_data) {
-		data = early_memremap(pa_data, PAGE_SIZE);
+		u32 data_len, map_len;
+
+		map_len = max(PAGE_SIZE - (pa_data & ~PAGE_MASK),
+			      (u64)sizeof(struct setup_data));
+		data = early_memremap(pa_data, map_len);
+		data_len = data->len + sizeof(struct setup_data);
+		if (data_len > map_len) {
+			early_iounmap(data, map_len);
+			data = early_memremap(pa_data, data_len);
+			map_len = data_len;
+		}
+
 		switch (data->type) {
 		case SETUP_E820_EXT:
-			parse_e820_ext(data, pa_data);
+			parse_e820_ext(data);
 			break;
 		default:
 			break;
 		}
 		pa_data = data->next;
-		early_iounmap(data, PAGE_SIZE);
+		early_iounmap(data, map_len);
 	}
 }