Re: [PATCH 16/16] KVM: arm/arm64: vgic: Replace spin_is_locked() with lockdep

From: Christoffer Dall <christoffer.dall@arm.com>
To: Lance Roy <ldr709@gmail.com>
Cc: linux-kernel@vger.kernel.org, Marc Zyngier <marc.zyngier@arm.com>,
	Eric Auger <eric.auger@redhat.com>,
	"Paul E. McKenney" <paulmck@linux.ibm.com>,
	kvmarm@lists.cs.columbia.edu,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 16/16] KVM: arm/arm64: vgic: Replace spin_is_locked() with lockdep
Date: Fri, 2 Nov 2018 19:45:33 +0100	[thread overview]
Message-ID: <20181102184533.GA12057@e113682-lin.lund.arm.com> (raw)
In-Reply-To: <20181003053902.6910-17-ldr709@gmail.com>

On Tue, Oct 02, 2018 at 10:39:02PM -0700, Lance Roy wrote:
> lockdep_assert_held() is better suited to checking locking requirements,
> since it won't get confused when someone else holds the lock. This is
> also a step towards possibly removing spin_is_locked().
> 
> Signed-off-by: Lance Roy <ldr709@gmail.com>
> Cc: Christoffer Dall <christoffer.dall@arm.com>
> Cc: Marc Zyngier <marc.zyngier@arm.com>
> Cc: Eric Auger <eric.auger@redhat.com>
> Cc: linux-arm-kernel@lists.infradead.org
> Cc: <kvmarm@lists.cs.columbia.edu>

Acked-by: Christoffer Dall <christoffer.dall@arm.com>

> ---
>  virt/kvm/arm/vgic/vgic.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/virt/kvm/arm/vgic/vgic.c b/virt/kvm/arm/vgic/vgic.c
> index 7cfdfbc910e0..50e25438fb3c 100644
> --- a/virt/kvm/arm/vgic/vgic.c
> +++ b/virt/kvm/arm/vgic/vgic.c
> @@ -196,7 +196,7 @@ void vgic_irq_set_phys_active(struct vgic_irq *irq, bool active)
>   */
>  static struct kvm_vcpu *vgic_target_oracle(struct vgic_irq *irq)
>  {
> -	DEBUG_SPINLOCK_BUG_ON(!spin_is_locked(&irq->irq_lock));
> +	lockdep_assert_held(&irq->irq_lock);
>  
>  	/* If the interrupt is active, it must stay on the current vcpu */
>  	if (irq->active)
> @@ -273,7 +273,7 @@ static void vgic_sort_ap_list(struct kvm_vcpu *vcpu)
>  {
>  	struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
>  
> -	DEBUG_SPINLOCK_BUG_ON(!spin_is_locked(&vgic_cpu->ap_list_lock));
> +	lockdep_assert_held(&vgic_cpu->ap_list_lock);
>  
>  	list_sort(NULL, &vgic_cpu->ap_list_head, vgic_irq_cmp);
>  }
> @@ -311,7 +311,7 @@ bool vgic_queue_irq_unlock(struct kvm *kvm, struct vgic_irq *irq,
>  {
>  	struct kvm_vcpu *vcpu;
>  
> -	DEBUG_SPINLOCK_BUG_ON(!spin_is_locked(&irq->irq_lock));
> +	lockdep_assert_held(&irq->irq_lock);
>  
>  retry:
>  	vcpu = vgic_target_oracle(irq);
> @@ -702,7 +702,7 @@ static inline void vgic_fold_lr_state(struct kvm_vcpu *vcpu)
>  static inline void vgic_populate_lr(struct kvm_vcpu *vcpu,
>  				    struct vgic_irq *irq, int lr)
>  {
> -	DEBUG_SPINLOCK_BUG_ON(!spin_is_locked(&irq->irq_lock));
> +	lockdep_assert_held(&irq->irq_lock);
>  
>  	if (kvm_vgic_global_state.type == VGIC_V2)
>  		vgic_v2_populate_lr(vcpu, irq, lr);
> @@ -736,7 +736,7 @@ static int compute_ap_list_depth(struct kvm_vcpu *vcpu,
>  
>  	*multi_sgi = false;
>  
> -	DEBUG_SPINLOCK_BUG_ON(!spin_is_locked(&vgic_cpu->ap_list_lock));
> +	lockdep_assert_held(&vgic_cpu->ap_list_lock);
>  
>  	list_for_each_entry(irq, &vgic_cpu->ap_list_head, ap_list) {
>  		int w;
> @@ -761,7 +761,7 @@ static void vgic_flush_lr_state(struct kvm_vcpu *vcpu)
>  	bool multi_sgi;
>  	u8 prio = 0xff;
>  
> -	DEBUG_SPINLOCK_BUG_ON(!spin_is_locked(&vgic_cpu->ap_list_lock));
> +	lockdep_assert_held(&vgic_cpu->ap_list_lock);
>  
>  	count = compute_ap_list_depth(vcpu, &multi_sgi);
>  	if (count > kvm_vgic_global_state.nr_lr || multi_sgi)
> -- 
> 2.19.0
> 
> 
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