linux-kernel - [PATCH -next] x86: Fix unused variable 'hi'

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Message-ID: <20210322035426.71169-2-xuyihang@huawei.com>
Date:   Mon, 22 Mar 2021 11:54:26 +0800
From:   Xu Yihang <xuyihang@...wei.com>
To:     <kys@...rosoft.com>, <haiyangz@...rosoft.com>,
        <sthemmin@...rosoft.com>, <wei.liu@...nel.org>,
        <tglx@...utronix.de>, <mingo@...hat.com>, <bp@...en8.de>,
        <x86@...nel.org>, <hpa@...or.com>
CC:     <linux-hyperv@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <xuyihang@...wei.com>, <johnny.chenyi@...wei.com>
Subject: [PATCH -next] x86: Fix unused variable 'hi'

Fixes the following W=1 kernel build warning(s):
arch/x86/hyperv/hv_apic.c:58:15: warning: variable ‘hi’ set but not used [-Wunused-but-set-variable]

Compiled with CONFIG_HYPERV enabled:
make allmodconfig ARCH=x86_64 CROSS_COMPILE=x86_64-linux-gnu-
make W=1 arch/x86/hyperv/hv_apic.o ARCH=x86_64 CROSS_COMPILE=x86_64-linux-gnu-

HV_X64_MSR_EOI stores on bit 31:0 and HV_X64_MSR_TPR stores in bit 7:0, which means higher 32 bits are not really used, therefore __maybe_unused added.

Reported-by: Hulk Robot <hulkci@...wei.com>
Signed-off-by: Xu Yihang <xuyihang@...wei.com>
---
 arch/x86/hyperv/hv_apic.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/hyperv/hv_apic.c b/arch/x86/hyperv/hv_apic.c
index 284e73661a18..c0b0a5774f31 100644
--- a/arch/x86/hyperv/hv_apic.c
+++ b/arch/x86/hyperv/hv_apic.c
@@ -55,7 +55,8 @@ static void hv_apic_icr_write(u32 low, u32 id)
 
 static u32 hv_apic_read(u32 reg)
 {
-	u32 reg_val, hi;
+	u32 hi __maybe_unused;
+	u32 reg_val;
 
 	switch (reg) {
 	case APIC_EOI:
-- 
2.17.1