Re: [PATCH for_v23 1/3] x86/sgx: Update the free page count in a single operation

[Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>]

On Tue, Oct 22, 2019 at 03:49:20PM -0700, Sean Christopherson wrote:
> Use atomic_add() instead of running atomic_inc() in a loop to manually
> do the equivalent addition.
> 
> Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
> ---
>  arch/x86/kernel/cpu/sgx/main.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
> index 499a9b0740c8..d45bf6fca0c8 100644
> --- a/arch/x86/kernel/cpu/sgx/main.c
> +++ b/arch/x86/kernel/cpu/sgx/main.c
> @@ -195,8 +195,7 @@ static bool __init sgx_alloc_epc_section(u64 addr, u64 size,
>  		list_add_tail(&page->list, &section->unsanitized_page_list);
>  	}
>  
> -	for (i = 0; i < nr_pages; i++)
> -		atomic_inc(&sgx_nr_free_pages);
> +	atomic_add(nr_pages, &sgx_nr_free_pages);
>  
>  	return true;
>  
> -- 
> 2.22.0
> 

There reason I used atomic_inc() was that atomic_add() takes int that
could potentially overflow.

I'll ignore this as I'll do the revert that I promised to do.

/Jarkko