Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <33aafc05-daa1-50e0-00ab-dab97bb8a879@arm.com>
Date:   Wed, 6 Jul 2022 10:20:05 +0100
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101
 Thunderbird/91.9.1
Subject: Re: [PATCH] KVM: arm64: Use the bitmap API to allocate bitmaps
Content-Language: en-US
To:     Christophe JAILLET <christophe.jaillet@wanadoo.fr>,
        Marc Zyngier <maz@kernel.org>,
        James Morse <james.morse@arm.com>,
        Alexandru Elisei <alexandru.elisei@arm.com>,
        Suzuki K Poulose <suzuki.poulose@arm.com>,
        Oliver Upton <oliver.upton@linux.dev>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>
Cc:     linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu
References: <a93d3e94be2003922c7e9652b57e96261cc47641.1656961792.git.christophe.jaillet@wanadoo.fr>
From:   Vladimir Murzin <vladimir.murzin@arm.com>
In-Reply-To: <a93d3e94be2003922c7e9652b57e96261cc47641.1656961792.git.christophe.jaillet@wanadoo.fr>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 7/4/22 20:10, Christophe JAILLET wrote:
> Use bitmap_zalloc()/bitmap_free() instead of hand-writing them.
> 
> It is less verbose and it improves the semantic.
> 
> While at it, turn a bitmap_clear() into an equivalent bitmap_zero(). It is
> also less verbose.
> 
> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
> ---
>  arch/arm64/kvm/vmid.c | 7 +++----
>  1 file changed, 3 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/arm64/kvm/vmid.c b/arch/arm64/kvm/vmid.c
> index d78ae63d7c15..f4612cdb60ff 100644
> --- a/arch/arm64/kvm/vmid.c
> +++ b/arch/arm64/kvm/vmid.c
> @@ -47,7 +47,7 @@ static void flush_context(void)
>  	int cpu;
>  	u64 vmid;
>  
> -	bitmap_clear(vmid_map, 0, NUM_USER_VMIDS);
> +	bitmap_zero(vmid_map, NUM_USER_VMIDS);
>  
>  	for_each_possible_cpu(cpu) {
>  		vmid = atomic64_xchg_relaxed(&per_cpu(active_vmids, cpu), 0);
> @@ -182,8 +182,7 @@ int kvm_arm_vmid_alloc_init(void)
>  	 */
>  	WARN_ON(NUM_USER_VMIDS - 1 <= num_possible_cpus());
>  	atomic64_set(&vmid_generation, VMID_FIRST_VERSION);
> -	vmid_map = kcalloc(BITS_TO_LONGS(NUM_USER_VMIDS),
> -			   sizeof(*vmid_map), GFP_KERNEL);
> +	vmid_map = bitmap_zalloc(NUM_USER_VMIDS, GFP_KERNEL);
>  	if (!vmid_map)
>  		return -ENOMEM;
>  
> @@ -192,5 +191,5 @@ int kvm_arm_vmid_alloc_init(void)
>  
>  void kvm_arm_vmid_alloc_free(void)
>  {
> -	kfree(vmid_map);
> +	bitmap_free(vmid_map);
>  }

FWIW

Reviewed-by: Vladimir Murzin <vladimir.murzin@arm.com>

Cheers
Vladimir