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Subject: Re: [PATCH] net/core: use xx_zalloc instead xx_alloc and memset
From:   Joe Perches <joe@perches.com>
To:     Tian Tao <tiantao6@hisilicon.com>, davem@davemloft.net,
        kuba@kernel.org, linmiaohe@huawei.com, martin.varghese@nokia.com,
        pshelar@ovn.org, pabeni@redhat.com, fw@strlen.de,
        viro@zeniv.linux.org.uk, gnault@redhat.com,
        steffen.klassert@secunet.com, kyk.segfault@gmail.com,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Date:   Wed, 18 Nov 2020 00:31:10 -0800
In-Reply-To: <1605687308-57318-1-git-send-email-tiantao6@hisilicon.com>
References: <1605687308-57318-1-git-send-email-tiantao6@hisilicon.com>
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On Wed, 2020-11-18 at 16:15 +0800, Tian Tao wrote:
> use kmem_cache_zalloc instead kmem_cache_alloc and memset.
[]
> diff --git a/net/core/skbuff.c b/net/core/skbuff.c
[]
> @@ -313,12 +313,10 @@ struct sk_buff *__build_skb(void *data, unsigned int frag_size)
> ?{
> ?	struct sk_buff *skb;
> ?
> -	skb = kmem_cache_alloc(skbuff_head_cache, GFP_ATOMIC);
> +	skb = kmem_cache_zalloc(skbuff_head_cache, GFP_ATOMIC);
> ?	if (unlikely(!skb))
> ?		return NULL;
> ?
> -	memset(skb, 0, offsetof(struct sk_buff, tail));
> -
> ?	return __build_skb_around(skb, data, frag_size);
> ?}
> ?
> 
> @@ -6170,12 +6168,10 @@ static void *skb_ext_get_ptr(struct skb_ext *ext, enum skb_ext_id id)
> ??*/
> ?struct skb_ext *__skb_ext_alloc(gfp_t flags)
> ?{
> -	struct skb_ext *new = kmem_cache_alloc(skbuff_ext_cache, flags);
> +	struct skb_ext *new = kmem_cache_zalloc(skbuff_ext_cache, flags);
> ?
> -	if (new) {
> -		memset(new->offset, 0, sizeof(new->offset));
> +	if (new)
> ?		refcount_set(&new->refcnt, 1);
> -	}
> ?
> ?	return new;
> ?}

I think it'd be nicer to use the same form for both of these functions.
This could be:

struct skb_ext *__skb_ext_alloc(gfp_t flags)
{
	struct skb_ext *new;

	new = kmem_cache_zalloc(skbbuff_ext_cache, flags);
	if (unlikely(!new))
		return NULL;

	refcount_set(&new->refcnt, 1);

	return new;
}