x86, mm: Let "memmap=" take more entries one time

Current "memmap=" only can take one entry every time.
when we have more entries, we have to use memmap= for each of them.

For pxe booting, we have command line length limitation, those extra
"memmap=" would waste too much space.

This patch make memmap= could take several entries one time,
and those entries will be split with ','

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/1353123563-3103-47-git-send-email-yinghai@kernel.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

arch/x86/kernel/e820.c

@@ -835,7 +835,7 @@ static int __init parse_memopt(char *p)
 }
 early_param("mem", parse_memopt);
 
-static int __init parse_memmap_opt(char *p)
+static int __init parse_memmap_one(char *p)
 {
 	char *oldp;
 	u64 start_at, mem_size;
@@ -877,6 +877,20 @@ static int __init parse_memmap_opt(char *p)
 
 	return *p == '\0' ? 0 : -EINVAL;
 }
+static int __init parse_memmap_opt(char *str)
+{
+	while (str) {
+		char *k = strchr(str, ',');
+
+		if (k)
+			*k++ = 0;
+
+		parse_memmap_one(str);
+		str = k;
+	}
+
+	return 0;
+}
 early_param("memmap", parse_memmap_opt);
 
 void __init finish_e820_parsing(void)