[PATCH 3.4 151/214] x86,efi: Check max_size only if it is non-zero.

Greg Kroah-Hartman
2014-06-05T04:39:44Z

From: Richard Weinberger <richard@nod.at>

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>
Cc: Rui Xiang <rui.xiang@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/x86/platform/efi/efi.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -979,7 +979,12 @@ efi_status_t efi_query_variable_store(u3
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;