Re: [PATCH] x86/xen: Remove use of VLAs

[Ingo Molnar]

* Laura Abbott <labbott@xxxxxxxxxx> wrote:

> There's an ongoing effort to remove VLAs[1] from the kernel to eventually
> turn on -Wvla. The few VLAs in use have an upper bound based on a size
> of 64K. This doesn't produce an excessively large stack so just switch
> the upper bound.
> 
> [1] https://lkml.org/lkml/2018/3/7/621
> 
> Signed-off-by: Laura Abbott <labbott@xxxxxxxxxx>
> ---
>  arch/x86/xen/enlighten_pv.c | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
> index c36d23aa6c35..d96a5a535cbb 100644
> --- a/arch/x86/xen/enlighten_pv.c
> +++ b/arch/x86/xen/enlighten_pv.c
> @@ -421,8 +421,7 @@ static void xen_load_gdt(const struct desc_ptr *dtr)
>  {
>  	unsigned long va = dtr->address;
>  	unsigned int size = dtr->size + 1;
> -	unsigned pages = DIV_ROUND_UP(size, PAGE_SIZE);
> -	unsigned long frames[pages];
> +	unsigned long frames[DIV_ROUND_UP(SZ_64K, PAGE_SIZE)];
>  	int f;
>  
>  	/*
> @@ -470,8 +469,7 @@ static void __init xen_load_gdt_boot(const struct desc_ptr *dtr)
>  {
>  	unsigned long va = dtr->address;
>  	unsigned int size = dtr->size + 1;
> -	unsigned pages = DIV_ROUND_UP(size, PAGE_SIZE);
> -	unsigned long frames[pages];
> +	unsigned long frames[DIV_ROUND_UP(SZ_64K, PAGE_SIZE)];
>  	int f;

Reviewed-by: Ingo Molnar <mingo@xxxxxxxxxx>

Thanks,

	Ingo