Re: [PATCH] EFI loader: remove dead code

[Linn Crosetto]

On Tue, Nov 01, 2016 at 08:38:08PM +0300, Eugene Korenevsky wrote:
> *e820ext is always NULL in 'alloc_e820ext()' (see the code of 'exit_boot()').
> Therefore the 'if' condition is always false and the entire 'if' statement is
> pointless. Remove it.
> 
> ---
>  arch/x86/boot/compressed/eboot.c | 6 ------
>  1 file changed, 6 deletions(-)
> 
> diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c
> index cc69e37..edfd4d6 100644
> --- a/arch/x86/boot/compressed/eboot.c
> +++ b/arch/x86/boot/compressed/eboot.c
> @@ -956,12 +956,6 @@ static efi_status_t alloc_e820ext(u32 nr_desc, struct setup_data **e820ext,
>  	size = sizeof(struct setup_data) +
>  		sizeof(struct e820entry) * nr_desc;
>  
> -	if (*e820ext) {
> -		efi_call_early(free_pool, *e820ext);
> -		*e820ext = NULL;
> -		*e820ext_size = 0;
> -	}
> -

I agree with your reading of the code. On the other hand, alloc_e820ext()
has no knowledge of the 'first' flag used in exit_boot_func() so the call to
free provides some assurance that memory isn't leaked if the calling code is
changed.

If the caller is responsible for freeing the memory in such a case, then
alloc_e820ext() should at least return an error.

--
Linn