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

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 <olivier.martin@arm.com>
Reviewed-by: Olivier Martin <olivier.martin@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Cc: Leif Lindholm <leif.lindholm@linaro.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>

arch/x86/boot/compressed/eboot.c

@@ -167,31 +167,31 @@ efi_file_size(efi_system_table_t *sys_table, void *__fh,
 }
 
 static inline efi_status_t
-efi_file_read(void *__fh, void *handle, unsigned long *size, void *addr)
+efi_file_read(void *handle, unsigned long *size, void *addr)
 {
 	unsigned long func;
 
 	if (efi_early->is64) {
-		efi_file_handle_64_t *fh = __fh;
+		efi_file_handle_64_t *fh = handle;
 
 		func = (unsigned long)fh->read;
 		return efi_early->call(func, handle, size, addr);
 	} else {
-		efi_file_handle_32_t *fh = __fh;
+		efi_file_handle_32_t *fh = handle;
 
 		func = (unsigned long)fh->read;
 		return efi_early->call(func, handle, size, addr);
 	}
 }
 
-static inline efi_status_t efi_file_close(void *__fh, void *handle)
+static inline efi_status_t efi_file_close(void *handle)
 {
 	if (efi_early->is64) {
-		efi_file_handle_64_t *fh = __fh;
+		efi_file_handle_64_t *fh = handle;
 
 		return efi_early->call((unsigned long)fh->close, handle);
 	} else {
-		efi_file_handle_32_t *fh = __fh;
+		efi_file_handle_32_t *fh = handle;
 
 		return efi_early->call((unsigned long)fh->close, handle);
 	}

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

@@ -397,7 +397,7 @@ static efi_status_t handle_cmdline_files(efi_system_table_t *sys_table_arg,
 				else
 					chunksize = size;
 
-				status = efi_file_read(fh, files[j].handle,
+				status = efi_file_read(files[j].handle,
 						       &chunksize,
 						       (void *)addr);
 				if (status != EFI_SUCCESS) {
@@ -408,7 +408,7 @@ static efi_status_t handle_cmdline_files(efi_system_table_t *sys_table_arg,
 				size -= chunksize;
 			}
 
-			efi_file_close(fh, files[j].handle);
+			efi_file_close(files[j].handle);
 		}
 
 	}
@@ -425,7 +425,7 @@ static efi_status_t handle_cmdline_files(efi_system_table_t *sys_table_arg,
 
 close_handles:
 	for (k = j; k < i; k++)
-		efi_file_close(fh, files[k].handle);
+		efi_file_close(files[k].handle);
 free_files:
 	efi_call_early(free_pool, files);
 fail: