linux-kernel - Re: [PATCH] x86/xen: clean up clang build warning

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Date:   Mon, 18 Sep 2017 10:43:22 +0200
From:   Juergen Gross <jgross@...e.com>
To:     Colin King <colin.king@...onical.com>,
        Boris Ostrovsky <boris.ostrovsky@...cle.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        "H . Peter Anvin" <hpa@...or.com>, x86@...nel.org,
        xen-devel@...ts.xenproject.org
Cc:     kernel-janitors@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] x86/xen: clean up clang build warning

On 18/09/17 10:38, Colin King wrote:
> From: Colin Ian King <colin.king@...onical.com>
> 
> In the case where sizeof(maddr) != sizeof(long) p is initialized and
> never read and clang throws a warning on this.  Move declaration of
> p to clean up the clang build warning:
> 
> warning: Value stored to 'p' during its initialization is never read
> 
> Signed-off-by: Colin Ian King <colin.king@...onical.com>

With the code style issue pointed out below fixed:

Reviewed-by: Juergen Gross <jgross@...e.com>

> ---
>  arch/x86/include/asm/xen/hypercall.h | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/x86/include/asm/xen/hypercall.h b/arch/x86/include/asm/xen/hypercall.h
> index 9606688caa4b..5ff77cb2529e 100644
> --- a/arch/x86/include/asm/xen/hypercall.h
> +++ b/arch/x86/include/asm/xen/hypercall.h
> @@ -552,13 +552,13 @@ static inline void
>  MULTI_update_descriptor(struct multicall_entry *mcl, u64 maddr,
>  			struct desc_struct desc)
>  {
> -	u32 *p = (u32 *) &desc;
> -
>  	mcl->op = __HYPERVISOR_update_descriptor;
>  	if (sizeof(maddr) == sizeof(long)) {
>  		mcl->args[0] = maddr;
>  		mcl->args[1] = *(unsigned long *)&desc;
>  	} else {
> +		u32 *p = (u32 *) &desc;

Please omit the space here      ^


Juergen

> +
>  		mcl->args[0] = maddr;
>  		mcl->args[1] = maddr >> 32;
>  		mcl->args[2] = *p++;
>