[PATCH -mm 1/4] x86_64 boot: Add free_early to early reservation machanism

["Huang, Ying" <ying.huang@intel.com>]

Add free_early to early reservation mechanism.

Signed-off-by: Huang Ying <ying.huang@intel.com>

---
 arch/x86/kernel/e820_64.c |   17 +++++++++++++++++
 include/asm-x86/e820_64.h |    1 +
 2 files changed, 18 insertions(+)

--- a/arch/x86/kernel/e820_64.c
+++ b/arch/x86/kernel/e820_64.c
@@ -84,6 +84,23 @@ void __init reserve_early(unsigned long 
 		strncpy(r->name, name, sizeof(r->name) - 1);
 }
 
+void __init free_early(unsigned long start, unsigned long end)
+{
+	int i, j;
+	struct early_res *r;
+	for (i = 0; i < MAX_EARLY_RES && early_res[i].end; i++) {
+		r = &early_res[i];
+		if (start == r->start && end == r->end)
+			break;
+	}
+	if (i >= MAX_EARLY_RES || !early_res[i].end)
+		panic("free_early on not reserved area: %lx-%lx!", start, end);
+	for (j = i+1; j < MAX_EARLY_RES && early_res[j].end; j++) ;
+	memcpy(&early_res[i], &early_res[i+1],
+	       (j-1-i) * sizeof(struct early_res));
+	early_res[j-1].end = 0;
+}
+
 void __init early_res_to_bootmem(void)
 {
 	int i;
--- a/include/asm-x86/e820_64.h
+++ b/include/asm-x86/e820_64.h
@@ -41,6 +41,7 @@ extern struct e820map e820;
 extern void update_e820(void);
 
 extern void reserve_early(unsigned long start, unsigned long end, char *name);
+extern void free_early(unsigned long start, unsigned long end);
 extern void early_res_to_bootmem(void);
 
 #endif/*!__ASSEMBLY__*/