linux-kernel - Re: [PATCH 3/4] KVM-S390: Less function calls in kvm_s390_import_bp

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <5da7978a-922b-8ccc-fce4-2bffffca888f@users.sourceforge.net>
Date:   Mon, 22 Aug 2016 23:17:26 +0200
From:   SF Markus Elfring <elfring@...rs.sourceforge.net>
To:     Cornelia Huck <cornelia.huck@...ibm.com>
Cc:     kvm@...r.kernel.org, linux-s390@...r.kernel.org,
        Christian Bornträger <borntraeger@...ibm.com>,
        David Hildenbrand <dahi@...ux.vnet.ibm.com>,
        Heiko Carstens <heiko.carstens@...ibm.com>,
        Martin Schwidefsky <schwidefsky@...ibm.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Radim Krčmář <rkrcmar@...hat.com>,
        LKML <linux-kernel@...r.kernel.org>,
        kernel-janitors@...r.kernel.org,
        Julia Lawall <julia.lawall@...6.fr>
Subject: Re: [PATCH 3/4] KVM-S390: Less function calls in
 kvm_s390_import_bp_data() after error detection

>>>> @@ -273,10 +273,12 @@ int kvm_s390_import_bp_data(struct kvm_vcpu *vcpu,
>>>>  	vcpu->arch.guestdbg.nr_hw_wp = nr_wp;
>>>>  	vcpu->arch.guestdbg.hw_wp_info = wp_info;
>>>>  	return 0;
>>>> -error:
>>>> -	kfree(bp_data);
>>>> -	kfree(wp_info);
>>>> +free_bp_info:
>>>>  	kfree(bp_info);
>>>> +free_wp_info:
>>>> +	kfree(wp_info);
>>>> +free_bp_data:
>>>> +	kfree(bp_data);
>>>>  	return ret;
>>>>  }
>>>>
>>>
>>> This replaces a perfectly fine fallthrough
>>
>> The usage of a single goto label like "error" seems to be convenient.
>> But how do these habits fit to the current Linux coding style convention?
>>
>>
>>> with some horrible labels.
>>
>> Do they explain better which processing steps should be performed
>> for an efficient exception handling in this function implementation?
> 
> *sigh*
> 
> It's _exception handling_. It does not need to be "efficient",

I imagine that run time situations could evolve where software efficiency
will also matter for this purpose.


> it needs to be easily parsable by humans.

I guess that we have got different preferences for this detail.


> If in doubt, the compiler will be _much_ better at optimizing
> that kind of stuff anyway.

Which compiler (or optimizer) implementation is capable to restructure
the jump targets for you automatically in the way I propose here?

Regards,
Markus