WMI: simplify handling of returned WMI blocks in parse_wdg()

There is no reason why we allocate memory and copy data into an
intermediate buffer, it is not like we are working with data coming
from userspace.

Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Signed-off-by: Matthew Garrett <mjg@redhat.com>

1 files changed, 4 insertions, 11 deletions

diff --git a/drivers/platform/x86/wmi.c b/drivers/platform/x86/wmi.c
index 81552bca6ae4..f6e85c8122de 100644
--- a/drivers/platform/x86/wmi.c
+++ b/drivers/platform/x86/wmi.c
@@ -475,7 +475,7 @@ const struct acpi_buffer *in)
 }
 EXPORT_SYMBOL_GPL(wmi_set_block);
 
-static void wmi_dump_wdg(struct guid_block *g)
+static void wmi_dump_wdg(const struct guid_block *g)
 {
         char guid_string[37];
 
@@ -812,7 +812,7 @@ static acpi_status parse_wdg(acpi_handle handle)
 {
         struct acpi_buffer out = {ACPI_ALLOCATE_BUFFER, NULL};
         union acpi_object *obj;
-        struct guid_block *gblock;
+        const struct guid_block *gblock;
         struct wmi_block *wblock;
         char guid_string[37];
         acpi_status status;
@@ -832,14 +832,9 @@ static acpi_status parse_wdg(acpi_handle handle)
                 goto out_free_pointer;
         }
 
+        gblock = (const struct guid_block *)obj->buffer.pointer;
         total = obj->buffer.length / sizeof(struct guid_block);
 
-        gblock = kmemdup(obj->buffer.pointer, obj->buffer.length, GFP_KERNEL);
-        if (!gblock) {
-                status = AE_NO_MEMORY;
-                goto out_free_pointer;
-        }
-
         for (i = 0; i < total; i++) {
                 /*
                   Some WMI devices, like those for nVidia hooks, have a
@@ -860,7 +855,7 @@ static acpi_status parse_wdg(acpi_handle handle)
                 wblock = kzalloc(sizeof(struct wmi_block), GFP_KERNEL);
                 if (!wblock) {
                         status = AE_NO_MEMORY;
-                        goto out_free_gblock;
+                        goto out_free_pointer;
                 }
 
                 wblock->gblock = gblock[i];
@@ -872,8 +867,6 @@ static acpi_status parse_wdg(acpi_handle handle)
                 list_add_tail(&wblock->list, &wmi_blocks.list);
         }
 
-out_free_gblock:
-        kfree(gblock);
 out_free_pointer:
         kfree(out.pointer);