linux-kernel - Re: [PATCH 1/2] tpm/tpm_ppi: Do not compare strcmp(a,b) == -1

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Date:	Wed, 30 Oct 2013 20:35:36 +0100
From:	Peter Hüwe <PeterHuewe@....de>
To:	Joe Perches <joe@...ches.com>,
	Jason Gunthorpe <jgunthorpe@...idianresearch.com>
Cc:	Ashley Lai <ashley@...leylai.com>, Rajiv Andrade <mail@...jiv.net>,
	Marcel Selhorst <tpmdd@...horst.net>,
	tpmdd-devel@...ts.sourceforge.net, linux-kernel@...r.kernel.org,
	Xiaoyan Zhang <xiaoyan.zhang@...el.com>,
	Gang Wei <gang.wei@...el.com>, stable@...r.kernel.org
Subject: Re: [PATCH 1/2] tpm/tpm_ppi: Do not compare strcmp(a,b) == -1

Hi Joe, Jason
> fyi: using
> 	if (strcmp(foo, bar) < 0)
> is canonical.

Yeah of course you're both right - 
    if (strcmp(foo, bar) < 0) 
is the correct version.
Sorry about the rubbish patch.


> lib/string.c:strcmp returns only -1,0,1
> so that's what the arch versions should do too.
> However, arch implementations do vary...

Joe, You are right on this one as well.

I did not pay attention to where cscope did send me 
- it was arch/x86/boot/string.c which implements it as 

        while (*s1 || *s2) {
                delta = *s2 - *s1;
                if (delta)
                        return delta;
                s1++;
                s2++;
        }

Although I know that this is not used here, 
it differs from the version in lib. (Maybe worth changing?)


In anycase 
    if (strcmp(foo, bar) < 0)
is better than
    if (strcmp(foo, bar) == -1)
so I'll resend the patch.

Thanks for reviewing!

Peter

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