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Subject: Re: [PATCH] powerpc/setup_64: fix -Wempty-body warnings
To:     Qian Cai <cai@lca.pw>, mpe@ellerman.id.au
Cc:     paulus@samba.org, linuxppc-dev@lists.ozlabs.org,
        linux-kernel@vger.kernel.org
References: <1559765875-6328-1-git-send-email-cai@lca.pw>
From:   Tyrel Datwyler <tyreld@linux.vnet.ibm.com>
Message-ID: <bc6d4f20-7839-43c6-95b8-cace41b4487f@linux.vnet.ibm.com>
Date:   Wed, 5 Jun 2019 13:33:00 -0700
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On 06/05/2019 01:17 PM, Qian Cai wrote:
> At the beginning of setup_64.c, it has,
> 
>   #ifdef DEBUG
>   #define DBG(fmt...) udbg_printf(fmt)
>   #else
>   #define DBG(fmt...)
>   #endif

Simpler solution is just to define the debug in the else clause as such:

#define DBG(fmt...) do { } while(0)

-Tyrel

> 
> where DBG() could be compiled away, and generate warnings,
> 
> arch/powerpc/kernel/setup_64.c: In function 'initialize_cache_info':
> arch/powerpc/kernel/setup_64.c:579:49: warning: suggest braces around
> empty body in an 'if' statement [-Wempty-body]
>     DBG("Argh, can't find dcache properties !\n");
>                                                  ^
> arch/powerpc/kernel/setup_64.c:582:49: warning: suggest braces around
> empty body in an 'if' statement [-Wempty-body]
>     DBG("Argh, can't find icache properties !\n");
> 
> Signed-off-by: Qian Cai <cai@lca.pw>
> ---
>  arch/powerpc/kernel/setup_64.c | 9 +++++----
>  1 file changed, 5 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
> index 44b4c432a273..23758834324f 100644
> --- a/arch/powerpc/kernel/setup_64.c
> +++ b/arch/powerpc/kernel/setup_64.c
> @@ -575,12 +575,13 @@ void __init initialize_cache_info(void)
>  	 * d-cache and i-cache sizes... -Peter
>  	 */
>  	if (cpu) {
> -		if (!parse_cache_info(cpu, false, &ppc64_caches.l1d))
> +		/* Add an extra brace to silence -Wempty-body warnings. */
> +		if (!parse_cache_info(cpu, false, &ppc64_caches.l1d)) {
>  			DBG("Argh, can't find dcache properties !\n");
> -
> -		if (!parse_cache_info(cpu, true, &ppc64_caches.l1i))
> +		}
> +		if (!parse_cache_info(cpu, true, &ppc64_caches.l1i)) {
>  			DBG("Argh, can't find icache properties !\n");
> -
> +		}
>  		/*
>  		 * Try to find the L2 and L3 if any. Assume they are
>  		 * unified and use the D-side properties.
>