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

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Message-Id: <20160822213736.62f1ae29.cornelia.huck@de.ibm.com>
Date:   Mon, 22 Aug 2016 21:37:36 +0200
From:   Cornelia Huck <cornelia.huck@...ibm.com>
To:     SF Markus Elfring <elfring@...rs.sourceforge.net>
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

On Mon, 22 Aug 2016 18:56:47 +0200
SF Markus Elfring <elfring@...rs.sourceforge.net> wrote:

> >> @@ -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", it needs
to be easily parsable by humans. If in doubt, the compiler will be
_much_ better at optimizing that kind of stuff anyway.

So still NACK.