Re: [PATCH 1/8] riscv: move riscv_noncoherent_supported() out of ZICBOM probe

Conor Dooley
2022-10-08T13:06:31Z

On Thu, Oct 06, 2022 at 03:08:11PM +0800, Jisheng Zhang wrote:
> It's a bit wired to call riscv_noncoherent_supported() once when
> insmod a module. Move the calling out of feature patch func.
>
> Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
> ---
> arch/riscv/kernel/cpufeature.c | 7 +------
> arch/riscv/kernel/setup.c | 4 ++++
> 2 files changed, 5 insertions(+), 6 deletions(-)
>
> diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
> index 3b5583db9d80..03611b3ef45e 100644
> --- a/arch/riscv/kernel/cpufeature.c
> +++ b/arch/riscv/kernel/cpufeature.c
> @@ -272,12 +272,7 @@ static bool __init_or_module cpufeature_probe_zicbom(unsigned int stage)
> case RISCV_ALTERNATIVES_EARLY_BOOT:
> return false;
> default:
> - if (riscv_isa_extension_available(NULL, ZICBOM)) {
> - riscv_noncoherent_supported();
> - return true;
> - } else {
> - return false;
> - }
> + return riscv_isa_extension_available(NULL, ZICBOM);
> }
> #endif
>
> diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
> index 2dfc463b86bb..1a055c3f5d9d 100644
> --- a/arch/riscv/kernel/setup.c
> +++ b/arch/riscv/kernel/setup.c
> @@ -299,6 +299,10 @@ void __init setup_arch(char **cmdline_p)
> riscv_init_cbom_blocksize();
> riscv_fill_hwcap();
> apply_boot_alternatives();
> +#ifdef CONFIG_RISCV_DMA_NONCOHERENT
> + if (riscv_isa_extension_available(NULL, ZICBOM))
> + riscv_noncoherent_supported();
> +#endif

I have a personal bias against ifdefs where possible, maybe @Heiko
remembers why riscv_noncoherent_supported() was not defined as something
like `void riscv_noncoherent_support(void){}` for when that CONFIG is
not enabled? If it was this could become a an IS_ENABLED & we wouldn't
have to be so careful about wrapping it's usage in ifdefs.

Your change in isolation makes sense to me though, so:
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>

Thanks,
Conor.

> }
>
> static int __init topology_init(void)
> --
> 2.37.2