linux-kernel - Re: [PATCH] arch/powerpc: Remove unnecessary endian conversion code in XICS

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Date:   Wed, 26 Jul 2023 13:37:06 +0530
From:   Gautam Menghani <Gautam.Menghani@...ux.ibm.com>
To:     Michael Ellerman <mpe@...erman.id.au>
Cc:     Gautam Menghani <gautam@...ux.ibm.com>, npiggin@...il.com,
        christophe.leroy@...roup.eu, linuxppc-dev@...ts.ozlabs.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] arch/powerpc: Remove unnecessary endian conversion code
 in XICS

On Thu, Jul 06, 2023 at 05:50:57PM +1000, Jordan Niethe wrote:
> 
> 
> On 30/6/23 3:56 pm, Gautam Menghani wrote:
> > Remove an unnecessary piece of code that does an endianness conversion but
> > does not use the result. The following warning was reported by Clang's
> > static analyzer:
> > 
> > arch/powerpc/sysdev/xics/ics-opal.c:114:2: warning: Value stored to
> > 'server' is never read [deadcode.DeadStores]
> >          server = be16_to_cpu(oserver);
> > 
> > As the result of endianness conversion is never used, delete the line
> > and fix the warning.
> > 
> > Signed-off-by: Gautam Menghani <gautam@...ux.ibm.com>
> 
> 'server' was used as a parameter to opal_get_xive() in commit 5c7c1e9444d8
> ("powerpc/powernv: Add OPAL ICS backend") when it was introduced. 'server'
> was also used in an error message for the call to opal_get_xive().
> 
> 'server' was always later set by a call to ics_opal_mangle_server() before
> being used.
> 
> Commit bf8e0f891a32 ("powerpc/powernv: Fix endian issues in OPAL ICS
> backend") used a new variable 'oserver' as the parameter to opal_get_xive()
> instead of 'server' for endian correctness. It also removed 'server' from
> the error message for the call to opal_get_xive().
> 
> It was commit bf8e0f891a32 that added the unnecessary conversion and never
> used the result.
> 
> Reviewed-by: Jordan Niethe <jniethe5@...il.com>
> 

Hello Michael,

Do you have any more questions on this patch or is it good to go?

Thanks,
Gautam