ACPI: use memory_read_from_buffer()

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Acked-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 2 insertions, 13 deletions

diff --git a/drivers/acpi/system.c b/drivers/acpi/system.c
index 769f24855eb6..5bd2dec9a7ac 100644
--- a/drivers/acpi/system.c
+++ b/drivers/acpi/system.c
@@ -77,7 +77,6 @@ static ssize_t acpi_table_show(struct kobject *kobj,
             container_of(bin_attr, struct acpi_table_attr, attr);
         struct acpi_table_header *table_header = NULL;
         acpi_status status;
-        ssize_t ret_count = count;
 
         status =
             acpi_get_table(table_attr->name, table_attr->instance,
@@ -85,18 +84,8 @@ static ssize_t acpi_table_show(struct kobject *kobj,
         if (ACPI_FAILURE(status))
                 return -ENODEV;
 
-        if (offset >= table_header->length) {
-                ret_count = 0;
-                goto end;
-        }
-
-        if (offset + ret_count > table_header->length)
-                ret_count = table_header->length - offset;
-
-        memcpy(buf, ((char *)table_header) + offset, ret_count);
-
-      end:
-        return ret_count;
+        return memory_read_from_buffer(buf, count, &offset,
+                                        table_header, table_header->length);
 }
 
 static void acpi_table_attr_init(struct acpi_table_attr *table_attr,