* Re: [PATCH] KVM: remove redundant code in kvm_arch_vm_ioctl
@ 2019-10-21 8:39 linmiaohe
0 siblings, 0 replies; 4+ messages in thread
From: linmiaohe @ 2019-10-21 8:39 UTC (permalink / raw)
To: Thomas Gleixner
Cc: pbonzini, rkrcmar, sean.j.christopherson, vkuznets, wanpengli,
jmattson, joro, mingo, bp, hpa, x86, kvm, linux-kernel
On Mon, 21 Oct 2019, tglx wrote:
>On Mon, 21 Oct 2019, Miaohe Lin wrote:
>> If we reach here with r = 0, we will reassign r = 0 unnecesarry, then
>> do the label set_irqchip_out work.
>> If we reach here with r != 0, then we will do the label work directly.
>> So this if statement and r = 0 assignment is redundant.
>
>Can you please get rid of that odd jump label completely?
>
> if (irqchip_kernel(kvm))
> r = kvm_vm_ioctl_set_irqchip(kvm, chip);
>
>Hmm?
Sure, thanks for your reply. I will send patch v2 to complete it.
Thanks again.
^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH] KVM: remove redundant code in kvm_arch_vm_ioctl
@ 2019-10-21 2:52 Miaohe Lin
2019-10-21 8:16 ` Thomas Gleixner
0 siblings, 1 reply; 4+ messages in thread
From: Miaohe Lin @ 2019-10-21 2:52 UTC (permalink / raw)
To: pbonzini, rkrcmar, sean.j.christopherson, vkuznets, wanpengli,
jmattson, joro, tglx, mingo, bp, hpa
Cc: x86, kvm, linux-kernel, linmiaohe
If we reach here with r = 0, we will reassign r = 0
unnecesarry, then do the label set_irqchip_out work.
If we reach here with r != 0, then we will do the label
work directly. So this if statement and r = 0 assignment
is redundant.
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
---
arch/x86/kvm/x86.c | 3 ---
1 file changed, 3 deletions(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 661e2bf38526..0b3ebc2afb3d 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4916,9 +4916,6 @@ long kvm_arch_vm_ioctl(struct file *filp,
if (!irqchip_kernel(kvm))
goto set_irqchip_out;
r = kvm_vm_ioctl_set_irqchip(kvm, chip);
- if (r)
- goto set_irqchip_out;
- r = 0;
set_irqchip_out:
kfree(chip);
break;
--
2.19.1
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] KVM: remove redundant code in kvm_arch_vm_ioctl
2019-10-21 2:52 Miaohe Lin
@ 2019-10-21 8:16 ` Thomas Gleixner
2019-10-21 8:56 ` Paolo Bonzini
0 siblings, 1 reply; 4+ messages in thread
From: Thomas Gleixner @ 2019-10-21 8:16 UTC (permalink / raw)
To: Miaohe Lin
Cc: pbonzini, rkrcmar, sean.j.christopherson, vkuznets, wanpengli,
jmattson, joro, mingo, bp, hpa, x86, kvm, linux-kernel
On Mon, 21 Oct 2019, Miaohe Lin wrote:
> If we reach here with r = 0, we will reassign r = 0
> unnecesarry, then do the label set_irqchip_out work.
> If we reach here with r != 0, then we will do the label
> work directly. So this if statement and r = 0 assignment
> is redundant.
>
> Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
> ---
> arch/x86/kvm/x86.c | 3 ---
> 1 file changed, 3 deletions(-)
>
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 661e2bf38526..0b3ebc2afb3d 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -4916,9 +4916,6 @@ long kvm_arch_vm_ioctl(struct file *filp,
> if (!irqchip_kernel(kvm))
> goto set_irqchip_out;
> r = kvm_vm_ioctl_set_irqchip(kvm, chip);
> - if (r)
> - goto set_irqchip_out;
> - r = 0;
> set_irqchip_out:
> kfree(chip);
> break;
Can you please get rid of that odd jump label completely?
if (irqchip_kernel(kvm))
r = kvm_vm_ioctl_set_irqchip(kvm, chip);
Hmm?
Thanks,
tglx
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] KVM: remove redundant code in kvm_arch_vm_ioctl
2019-10-21 8:16 ` Thomas Gleixner
@ 2019-10-21 8:56 ` Paolo Bonzini
0 siblings, 0 replies; 4+ messages in thread
From: Paolo Bonzini @ 2019-10-21 8:56 UTC (permalink / raw)
To: Thomas Gleixner, Miaohe Lin
Cc: rkrcmar, sean.j.christopherson, vkuznets, wanpengli, jmattson,
joro, mingo, bp, hpa, x86, kvm, linux-kernel
On 21/10/19 10:16, Thomas Gleixner wrote:
> Can you please get rid of that odd jump label completely?
>
> if (irqchip_kernel(kvm))
> r = kvm_vm_ioctl_set_irqchip(kvm, chip);
Keeping the label has the advantage of making the get and set cases a
bit more similar (the get case has to do a copy_to_user after
kvm_vm_ioctl_get_irqchip returns). Unfortunately struct kvm_irqchip is
quite big (520 bytes) so we don't allocate it on the stack.
So I queued Miaohe's patch.
Paolo
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2019-10-21 8:56 UTC | newest]
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2019-10-21 2:52 Miaohe Lin
2019-10-21 8:16 ` Thomas Gleixner
2019-10-21 8:56 ` Paolo Bonzini
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