x86: trim mtrr don't close gap for resource allocation.

fix the bug reported here:

	http://bugzilla.kernel.org/show_bug.cgi?id=10232

use update_memory_range() instead of add_memory_range() directly
to avoid closing the gap.

( the new code only affects and runs on systems where the MTRR
  workaround triggers. )

Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

3 files changed, 55 insertions, 1 deletions

diff --git a/arch/x86/kernel/cpu/mtrr/main.c b/arch/x86/kernel/cpu/mtrr/main.c
index be83336fddb..a6450b3ae75 100644
--- a/arch/x86/kernel/cpu/mtrr/main.c
+++ b/arch/x86/kernel/cpu/mtrr/main.c
@@ -711,7 +711,8 @@ int __init mtrr_trim_uncached_memory(unsigned long end_pfn)
 		trim_size = end_pfn;
 		trim_size <<= PAGE_SHIFT;
 		trim_size -= trim_start;
-		add_memory_region(trim_start, trim_size, E820_RESERVED);
+		update_memory_range(trim_start, trim_size, E820_RAM,
+					E820_RESERVED);
 		update_e820();
 		return 1;
 	}
diff --git a/arch/x86/kernel/e820_32.c b/arch/x86/kernel/e820_32.c
index 4e16ef4a265..80444c5c9b1 100644
--- a/arch/x86/kernel/e820_32.c
+++ b/arch/x86/kernel/e820_32.c
@@ -749,6 +749,32 @@ static int __init parse_memmap(char *arg)
 	return 0;
 }
 early_param("memmap", parse_memmap);
+void __init update_memory_range(u64 start, u64 size, unsigned old_type,
+				unsigned new_type)
+{
+	int i;
+
+	BUG_ON(old_type == new_type);
+
+	for (i = 0; i < e820.nr_map; i++) {
+		struct e820entry *ei = &e820.map[i];
+		u64 final_start, final_end;
+		if (ei->type != old_type)
+			continue;
+		/* totally covered? */
+		if (ei->addr >= start && ei->size <= size) {
+			ei->type = new_type;
+			continue;
+		}
+		/* partially covered */
+		final_start = max(start, ei->addr);
+		final_end = min(start + size, ei->addr + ei->size);
+		if (final_start >= final_end)
+			continue;
+		add_memory_region(final_start, final_end - final_start,
+					 new_type);
+	}
+}
 void __init update_e820(void)
 {
 	u8 nr_map;
diff --git a/arch/x86/kernel/e820_64.c b/arch/x86/kernel/e820_64.c
index 9f65b4cc323..9be69712601 100644
--- a/arch/x86/kernel/e820_64.c
+++ b/arch/x86/kernel/e820_64.c
@@ -744,6 +744,33 @@ void __init finish_e820_parsing(void)
 	}
 }
 
+void __init update_memory_range(u64 start, u64 size, unsigned old_type,
+				unsigned new_type)
+{
+	int i;
+
+	BUG_ON(old_type == new_type);
+
+	for (i = 0; i < e820.nr_map; i++) {
+		struct e820entry *ei = &e820.map[i];
+		u64 final_start, final_end;
+		if (ei->type != old_type)
+			continue;
+		/* totally covered? */
+		if (ei->addr >= start && ei->size <= size) {
+			ei->type = new_type;
+			continue;
+		}
+		/* partially covered */
+		final_start = max(start, ei->addr);
+		final_end = min(start + size, ei->addr + ei->size);
+		if (final_start >= final_end)
+			continue;
+		add_memory_region(final_start, final_end - final_start,
+					 new_type);
+	}
+}
+
 void __init update_e820(void)
 {
 	u8 nr_map;