1 files changed, 33 insertions, 9 deletions

diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
index e52ad5d3792d..f7e300769966 100644
--- a/drivers/acpi/acpi_memhotplug.c
+++ b/drivers/acpi/acpi_memhotplug.c
@@ -78,6 +78,7 @@ struct acpi_memory_info {
 	unsigned short caching;	/* memory cache attribute */
 	unsigned short write_protect;	/* memory read/write attribute */
 	unsigned int enabled:1;
+	unsigned int failed:1;
 };
 
 struct acpi_memory_device {
@@ -257,9 +258,23 @@ static int acpi_memory_enable_device(struct acpi_memory_device *mem_device)
 			node = memory_add_physaddr_to_nid(info->start_addr);
 
 		result = add_memory(node, info->start_addr, info->length);
-		if (result)
+
+		/*
+		 * If the memory block has been used by the kernel, add_memory()
+		 * returns -EEXIST. If add_memory() returns the other error, it
+		 * means that this memory block is not used by the kernel.
+		 */
+		if (result && result != -EEXIST) {
+			info->failed = 1;
 			continue;
-		info->enabled = 1;
+		}
+
+		if (!result)
+			info->enabled = 1;
+		/*
+		 * Add num_enable even if add_memory() returns -EEXIST, so the
+		 * device is bound to this driver.
+		 */
 		num_enabled++;
 	}
 	if (!num_enabled) {
@@ -280,21 +295,30 @@ static int acpi_memory_enable_device(struct acpi_memory_device *mem_device)
 
 static int acpi_memory_remove_memory(struct acpi_memory_device *mem_device)
 {
-	int result;
+	int result = 0;
 	struct acpi_memory_info *info, *n;
 
 	list_for_each_entry_safe(info, n, &mem_device->res_list, list) {
-		if (info->enabled) {
-			result = remove_memory(info->start_addr, info->length);
-			if (result)
-				return result;
-		}
+		if (info->failed)
+			/* The kernel does not use this memory block */
+			continue;
+
+		if (!info->enabled)
+			/*
+			 * The kernel uses this memory block, but it may be not
+			 * managed by us.
+			 */
+			return -EBUSY;
+
+		result = remove_memory(info->start_addr, info->length);
+		if (result)
+			return result;
 
 		list_del(&info->list);
 		kfree(info);
 	}
 
-	return 0;
+	return result;
 }
 
 static void acpi_memory_device_notify(acpi_handle handle, u32 event, void *data)