efi: Pass correct file handle to efi_file_{read,close}

commit 47514c9 upstream.

We're currently passing the file handle for the root file system to
efi_file_read() and efi_file_close(), instead of the file handle for the
file we wish to read/close.

While this has worked up until now, it seems that it has only been by
pure luck. Olivier explains,

 "The issue is the UEFI Fat driver might return the same function for
  'fh->read()' and 'h->read()'. While in our case it does not work with
  a different implementation of EFI_SIMPLE_FILE_SYSTEM_PROTOCOL. In our
  case, we return a different pointer when reading a directory and
  reading a file."

Fixing this actually clears up the two functions because we can drop one
of the arguments, and instead only pass a file 'handle' argument.

Reported-by: Olivier Martin <[email protected]>
Reviewed-by: Olivier Martin <[email protected]>
Reviewed-by: Mark Rutland <[email protected]>
Cc: Leif Lindholm <[email protected]>
Signed-off-by: Matt Fleming <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: Matt Fleming

drivers/firmware/efi/efi-stub-helper.c

@@ -468,7 +468,7 @@ static efi_status_t handle_cmdline_files(efi_system_table_t *sys_table_arg,
 					chunksize = EFI_READ_CHUNK_SIZE;
 				else
 					chunksize = size;
-				status = efi_call_phys3(fh->read,
+				status = efi_call_phys3(files[j].handle->read,
 							files[j].handle,
 							&chunksize,
 							(void *)addr);
@@ -480,7 +480,7 @@ static efi_status_t handle_cmdline_files(efi_system_table_t *sys_table_arg,
 				size -= chunksize;
 			}
 
-			efi_call_phys1(fh->close, files[j].handle);
+			efi_call_phys1(files[j].handle->close, files[j].handle);
 		}
 
 	}
@@ -497,7 +497,7 @@ static efi_status_t handle_cmdline_files(efi_system_table_t *sys_table_arg,
 
 close_handles:
 	for (k = j; k < i; k++)
-		efi_call_phys1(fh->close, files[k].handle);
+		efi_call_phys1(files[k].handle->close, files[k].handle);
 free_files:
 	efi_call_phys1(sys_table_arg->boottime->free_pool, files);
 fail: