linux-kernel - [PATCH] KVM: arm64: pmu: Drop redundant check for non-NULL kvm_pmu

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Date:   Thu, 12 Oct 2023 12:16:17 +0530
From:   Anshuman Khandual <anshuman.khandual@....com>
To:     linux-arm-kernel@...ts.infradead.org
Cc:     Anshuman Khandual <anshuman.khandual@....com>,
        Marc Zyngier <maz@...nel.org>,
        Oliver Upton <oliver.upton@...ux.dev>,
        James Morse <james.morse@....com>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        kvmarm@...ts.linux.dev, linux-kernel@...r.kernel.org
Subject: [PATCH] KVM: arm64: pmu: Drop redundant check for non-NULL kvm_pmu_events

There is an allocated and valid struct kvm_pmu_events for each cpu on the
system via DEFINE_PER_CPU(). Hence there cannot be a NULL pointer accessed
via this_cpu_ptr() in the helper kvm_get_pmu_events(). Hence non-NULL check
for pmu in such places are redundant and can be dropped.

Cc: Marc Zyngier <maz@...nel.org>
Cc: Oliver Upton <oliver.upton@...ux.dev>
Cc: James Morse <james.morse@....com>
Cc: Suzuki K Poulose <suzuki.poulose@....com>
Cc: kvmarm@...ts.linux.dev
Cc: linux-arm-kernel@...ts.infradead.org
Cc: linux-kernel@...r.kernel.org
Signed-off-by: Anshuman Khandual <anshuman.khandual@....com>
---
 arch/arm64/kvm/pmu.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/kvm/pmu.c b/arch/arm64/kvm/pmu.c
index 0eea225fd09a..a243934c5568 100644
--- a/arch/arm64/kvm/pmu.c
+++ b/arch/arm64/kvm/pmu.c
@@ -39,7 +39,7 @@ void kvm_set_pmu_events(u32 set, struct perf_event_attr *attr)
 {
 	struct kvm_pmu_events *pmu = kvm_get_pmu_events();
 
-	if (!kvm_arm_support_pmu_v3() || !pmu || !kvm_pmu_switch_needed(attr))
+	if (!kvm_arm_support_pmu_v3() || !kvm_pmu_switch_needed(attr))
 		return;
 
 	if (!attr->exclude_host)
@@ -55,7 +55,7 @@ void kvm_clr_pmu_events(u32 clr)
 {
 	struct kvm_pmu_events *pmu = kvm_get_pmu_events();
 
-	if (!kvm_arm_support_pmu_v3() || !pmu)
+	if (!kvm_arm_support_pmu_v3())
 		return;
 
 	pmu->events_host &= ~clr;
-- 
2.25.1