2022-05-08 02:29:47

by Jürgen Groß

[permalink] [raw]
Subject: Re: [PATCH] x86: Function missing integer return value

On 05.05.22 13:32, Li kunyu wrote:
> This function may need to return a value
>
> Signed-off-by: Li kunyu <[email protected]>
> ---
> arch/x86/kvm/mmu/mmu.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
> index 64a2a7e2be90..68f33b932f94 100644
> --- a/arch/x86/kvm/mmu/mmu.c
> +++ b/arch/x86/kvm/mmu/mmu.c
> @@ -6500,6 +6500,8 @@ static int kvm_nx_lpage_recovery_worker(struct kvm *kvm, uintptr_t data)
>
> kvm_recover_nx_lpages(kvm);
> }
> +
> + return 0;

This statement is not reachable, so the patch is adding unneeded dead
code only.


Juergen


Attachments:
OpenPGP_0xB0DE9DD628BF132F.asc (3.08 kB)
OpenPGP public key
OpenPGP_signature (505.00 B)
OpenPGP digital signature
Download all attachments

2022-05-08 10:01:19

by Maciej S. Szmigiero

[permalink] [raw]
Subject: Re: [PATCH] x86: Function missing integer return value

On 5.05.2022 13:36, Juergen Gross wrote:
> On 05.05.22 13:32, Li kunyu wrote:
>> This function may need to return a value
>>
>> Signed-off-by: Li kunyu <[email protected]>
>> ---
>>   arch/x86/kvm/mmu/mmu.c | 2 ++
>>   1 file changed, 2 insertions(+)
>>
>> diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
>> index 64a2a7e2be90..68f33b932f94 100644
>> --- a/arch/x86/kvm/mmu/mmu.c
>> +++ b/arch/x86/kvm/mmu/mmu.c
>> @@ -6500,6 +6500,8 @@ static int kvm_nx_lpage_recovery_worker(struct kvm *kvm, uintptr_t data)
>>           kvm_recover_nx_lpages(kvm);
>>       }
>> +
>> +    return 0;
>
> This statement is not reachable, so the patch is adding unneeded dead
> code only.

Maybe some static checker isn't smart enough to figure this out.

In this case it would probably be better to also change:
> if (kthread_should_stop())
> return 0;

into:
> if (kthread_should_stop())
> break;

so the newly introduced code isn't dead.

> Juergen

Thanks,
Maciej

2022-05-09 05:09:06

by kunyu

[permalink] [raw]
Subject: Re: [PATCH] x86: Function missing integer return value


Hello, senior, I've considered break before, but I'm not sure if I want to execute more instructions.
Query break executed one more NOP instruction.