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SubjectRe: [PATCH] KVM: arm64: Avoid shadowing a previous local
On 2021-10-27 03:42, Qian Cai wrote:
> It is less-prone to have a different variable name from the one in a
> wider
> scope. This is also flagged by GCC (W=2):
>
> In file included from ./include/linux/kvm_host.h:39,
> from arch/arm64/kvm/arm.c:12:
> arch/arm64/kvm/arm.c: In function 'kvm_arch_vcpu_ioctl_run':
> ./arch/arm64/include/asm/kvm_host.h:638:26: warning: declaration of
> 'ret' shadows a previous local [-Wshadow]
> 638 | typeof(f(__VA_ARGS__)) ret; \
> | ^~~
> arch/arm64/kvm/arm.c:852:9: note: in expansion of macro
> 'kvm_call_hyp_ret'
> 852 | ret = kvm_call_hyp_ret(__kvm_vcpu_run, vcpu);
> | ^~~~~~~~~~~~~~~~
> arch/arm64/kvm/arm.c:773:6: note: shadowed declaration is here
> 773 | int ret;
> | ^~~
>
> Signed-off-by: Qian Cai <quic_qiancai@quicinc.com>
> ---
> arch/arm64/include/asm/kvm_host.h | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/arch/arm64/include/asm/kvm_host.h
> b/arch/arm64/include/asm/kvm_host.h
> index 4be8486042a7..4693d84ccd95 100644
> --- a/arch/arm64/include/asm/kvm_host.h
> +++ b/arch/arm64/include/asm/kvm_host.h
> @@ -635,16 +635,16 @@ void kvm_arm_resume_guest(struct kvm *kvm);
>
> #define kvm_call_hyp_ret(f, ...) \
> ({ \
> - typeof(f(__VA_ARGS__)) ret; \
> + typeof(f(__VA_ARGS__)) __ret; \
> \
> if (has_vhe()) { \
> - ret = f(__VA_ARGS__); \
> + __ret = f(__VA_ARGS__); \
> isb(); \
> } else { \
> - ret = kvm_call_hyp_nvhe(f, ##__VA_ARGS__); \
> + __ret = kvm_call_hyp_nvhe(f, ##__VA_ARGS__); \
> } \
> \
> - ret; \
> + __ret; \
> })
> #else /* __KVM_NVHE_HYPERVISOR__ */
> #define kvm_call_hyp(f, ...) f(__VA_ARGS__)

I don't think this makes much sense. This is bound to eventually clash
with another variable, and you're back to square one.

Thanks,

M.
--
Jazz is not dead. It just smells funny...

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