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)