x86: cleanup e820_setup_gap(), v2

e820_search_gap also take a end_addr parameter to limit search from
start_addr to end_addr.

Signed-off-by: AloK N Kataria <akataria@vmware.com>
Acked-by: Yinghai Lu <yhlu.kernel@gmail.com>
Cc: "lenb@kernel.org" <lenb@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/kernel/e820.c

@@ -487,17 +487,19 @@ void __init update_e820(void)
 	printk(KERN_INFO "modified physical RAM map:\n");
 	e820_print_map("modified");
 }
-
+#define MAX_GAP_END 0x100000000ull
 /*
- * Search for a gap in the e820 memory space from start_addr to 2^32.
+ * Search for a gap in the e820 memory space from start_addr to end_addr.
  */
 __init int e820_search_gap(unsigned long *gapstart, unsigned long *gapsize,
-		unsigned long start_addr)
+		unsigned long start_addr, unsigned long long end_addr)
 {
-	unsigned long long last = 0x100000000ull;
+	unsigned long long last;
 	int i = e820.nr_map;
 	int found = 0;
 
+	last = (end_addr && end_addr < MAX_GAP_END) ? end_addr : MAX_GAP_END;
+
 	while (--i >= 0) {
 		unsigned long long start = e820.map[i].addr;
 		unsigned long long end = start + e820.map[i].size;
@@ -537,7 +539,7 @@ __init void e820_setup_gap(void)
 
 	gapstart = 0x10000000;
 	gapsize = 0x400000;
-	found  = e820_search_gap(&gapstart, &gapsize, 0);
+	found  = e820_search_gap(&gapstart, &gapsize, 0, MAX_GAP_END);
 
 #ifdef CONFIG_X86_64
 	if (!found) {

include/asm-x86/e820.h

@@ -75,7 +75,7 @@ extern u64 e820_remove_range(u64 start, u64 size, unsigned old_type,
 extern void update_e820(void);
 extern void e820_setup_gap(void);
 extern int e820_search_gap(unsigned long *gapstart, unsigned long *gapsize,
-				unsigned long start_addr);
+			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);