x86,efi: Check max_size only if it is non-zero.

commit 7791c8423f1f7f4dad94e753bae67461d5b80be8 upstream.

Some EFI implementations return always a MaximumVariableSize of 0,
check against max_size only if it is non-zero.
My Intel DQ67SW desktop board has such an implementation.

Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index a20b5b38483777faab3d3e902c61ab6f68910d8e..3d7bb0535126159a5d3fe349d8030c04dc4fc5e2 100644 (file)
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -834,7 +834,12 @@ efi_status_t efi_query_variable_store(u32 attributes, unsigned long size)
        if (status != EFI_SUCCESS)
                return status;
 
-       if (!storage_size || size > remaining_size || size > max_size ||
+       if (!max_size && remaining_size > size)
+               printk_once(KERN_ERR FW_BUG "Broken EFI implementation"
+                           " is returning MaxVariableSize=0\n");
+
+       if (!storage_size || size > remaining_size ||
+           (max_size && size > max_size) ||
            (remaining_size - size) < (storage_size / 2))
                return EFI_OUT_OF_RESOURCES;