linux-kernel - Re: [PATCH] x86/hyperv: Use pointer from memcpy() call for assignment in hv_crash_setup

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Message-ID: <cea9d987-0231-4131-82ac-9ba8c852f963@linux.microsoft.com>
Date: Fri, 31 Oct 2025 14:58:56 +0530
From: Naman Jain <namjain@...ux.microsoft.com>
To: Markus Elfring <Markus.Elfring@....de>, linux-hyperv@...r.kernel.org,
 x86@...nel.org, Borislav Petkov <bp@...en8.de>,
 Dave Hansen <dave.hansen@...ux.intel.com>, Dexuan Cui <decui@...rosoft.com>,
 Haiyang Zhang <haiyangz@...rosoft.com>, "H. Peter Anvin" <hpa@...or.com>,
 Ingo Molnar <mingo@...hat.com>, "K. Y. Srinivasan" <kys@...rosoft.com>,
 Long Li <longli@...rosoft.com>, Mukesh Rathor <mrathor@...ux.microsoft.com>,
 Thomas Gleixner <tglx@...utronix.de>, Wei Liu <wei.liu@...nel.org>
Cc: LKML <linux-kernel@...r.kernel.org>, kernel-janitors@...r.kernel.org,
 Miaoqian Lin <linmq006@...il.com>
Subject: Re: [PATCH] x86/hyperv: Use pointer from memcpy() call for assignment
 in hv_crash_setup_trampdata()

On 10/31/2025 2:03 PM, Markus Elfring wrote:
> From: Markus Elfring <elfring@...rs.sourceforge.net>
> Date: Fri, 31 Oct 2025 09:24:31 +0100
> 
> A pointer was assigned to a variable. The same pointer was used for
> the destination parameter of a memcpy() call.
> This function is documented in the way that the same value is returned.
> Thus convert two separate statements into a direct variable assignment for
> the return value from a memory copy action.
> 
> The source code was transformed by using the Coccinelle software.
> 
> Signed-off-by: Markus Elfring <elfring@...rs.sourceforge.net>
> ---
>   arch/x86/hyperv/hv_crash.c | 4 +---
>   1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/arch/x86/hyperv/hv_crash.c b/arch/x86/hyperv/hv_crash.c
> index c0e22921ace1..745d02066308 100644
> --- a/arch/x86/hyperv/hv_crash.c
> +++ b/arch/x86/hyperv/hv_crash.c
> @@ -464,9 +464,7 @@ static int hv_crash_setup_trampdata(u64 trampoline_va)
>   		return -1;
>   	}
>   
> -	dest = (void *)trampoline_va;
> -	memcpy(dest, &hv_crash_asm32, size);
> -
> +	dest = memcpy((void *)trampoline_va, &hv_crash_asm32, size);
>   	dest += size;
>   	dest = (void *)round_up((ulong)dest, 16);
>   	tramp = (struct hv_crash_tramp_data *)dest;

I tried running spatch Coccinelle checks on this file, but could not get 
it to flag this improvement. Do you mind sharing more details on the 
issue reproduction please.

I am OK with this change, though it may cost code readability a little 
bit. But if this is a result of some known standard rule, added as part 
of these Coccinelle rules, we should be good.

Regards,
Naman