linux-kernel - [PATCH] KVM: arm64: Avoid shadowing a previous local

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Date:   Tue, 26 Oct 2021 22:42:12 -0400
From:   Qian Cai <quic_qiancai@...cinc.com>
To:     Marc Zyngier <maz@...nel.org>
CC:     James Morse <james.morse@....com>,
        Alexandru Elisei <alexandru.elisei@....com>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <kvmarm@...ts.cs.columbia.edu>, <linux-kernel@...r.kernel.org>,
        Qian Cai <quic_qiancai@...cinc.com>
Subject: [PATCH] KVM: arm64: Avoid shadowing a previous local

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@...cinc.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__)
-- 
2.30.2