efi, pstore: Read data from variable store before memcpy()

Seiji reported getting empty dmesg-* files, because the data was never
actually read in efi_pstore_read_func(), and so the memcpy() was copying
garbage data.

This patch necessitated adding __efivar_entry_get() which is callable
between efivar_entry_iter_{begin,end}(). We can also delete
__efivar_entry_size() because efi_pstore_read_func() was the only
caller.

Reported-by: Seiji Aguchi <seiji.aguchi@hds.com>
Tested-by: Seiji Aguchi <seiji.aguchi@hds.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Matthew Garrett <matthew.garrett@nebula.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/include/linux/efi.h b/include/linux/efi.h
index 3f7257f1f5e8..2bc0ad78d058 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -808,8 +808,9 @@ void efivar_entry_remove(struct efivar_entry *entry);
 int __efivar_entry_delete(struct efivar_entry *entry);
 int efivar_entry_delete(struct efivar_entry *entry);
 
-int __efivar_entry_size(struct efivar_entry *entry, unsigned long *size);
 int efivar_entry_size(struct efivar_entry *entry, unsigned long *size);
+int __efivar_entry_get(struct efivar_entry *entry, u32 *attributes,
+                       unsigned long *size, void *data);
 int efivar_entry_get(struct efivar_entry *entry, u32 *attributes,
                      unsigned long *size, void *data);
 int efivar_entry_set(struct efivar_entry *entry, u32 attributes,