linux-kernel - Re: [PATCH] iommu/vt-d: Use kcalloc() instead of kzalloc()

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Message-ID: <1e3b71a7-1515-4533-a102-34509f8b2f01@linux.intel.com>
Date: Mon, 26 Feb 2024 14:09:26 +0800
From: Baolu Lu <baolu.lu@...ux.intel.com>
To: Erick Archer <erick.archer@....com>, David Woodhouse
 <dwmw2@...radead.org>, Joerg Roedel <joro@...tes.org>,
 Will Deacon <will@...nel.org>, Robin Murphy <robin.murphy@....com>,
 "Gustavo A. R. Silva" <gustavoars@...nel.org>,
 Kees Cook <keescook@...omium.org>
Cc: baolu.lu@...ux.intel.com, iommu@...ts.linux.dev,
 linux-kernel@...r.kernel.org, linux-hardening@...r.kernel.org
Subject: Re: [PATCH] iommu/vt-d: Use kcalloc() instead of kzalloc()

On 2/12/24 1:51 AM, Erick Archer wrote:
> This is an effort to get rid of all multiplications from allocation
> functions in order to prevent integer overflows [1].
> 
> Here the multiplication is obviously safe because DMAR_LATENCY_NUM
> is the number of latency types defined in the "latency_type" enum.
> 
> enum latency_type {
> 	DMAR_LATENCY_INV_IOTLB = 0,
> 	DMAR_LATENCY_INV_DEVTLB,
> 	DMAR_LATENCY_INV_IEC,
> 	DMAR_LATENCY_PRQ,
> 	DMAR_LATENCY_NUM
> };
> 
> However, using kcalloc() is more appropriate [2] and improves
> readability. This patch has no effect on runtime behavior.
> 
> Link:https://github.com/KSPP/linux/issues/162  [1]
> Link:https://www.kernel.org/doc/html/next/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments  [2]
> Signed-off-by: Erick Archer<erick.archer@....com>
> ---
>   drivers/iommu/intel/perf.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)

I have queued this patch for v6.9.

Best regards,
baolu