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

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>

1 files changed, 6 insertions, 1 deletions

diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index c89c245eff40..3f96a487aa2a 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -1018,7 +1018,12 @@ 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;