Subject: Re: [PATCH v2 3/5] crypto/net/tcp: Use crypto_pool for TCP-MD5

From: Jakub Kicinski <[email-masked]>
Date: Fri, 6 Jan 2023 18:05:26 -0800

On Tue,  3 Jan 2023 18:42:55 +0000 Dmitry Safonov wrote:
> Use crypto_pool API that was designed with tcp_md5sig_pool in mind.
> The conversion to use crypto_pool will allow:
> - to reuse ahash_request(s) for different users
> - to allocate only one per-CPU scratch buffer rather than a new one for
>   each user
> - to have a common API for net/ users that need ahash on RX/TX fast path

>  config TCP_MD5SIG
>  	bool "TCP: MD5 Signature Option support (RFC2385)"
> -	select CRYPTO
> +	select CRYPTO_POOL

Are you sure we don't need to select CRYPTO any more?
select does not resolve dependencies.

>  	select CRYPTO_MD5
>  	help
>  	  RFC2385 specifies a method of giving MD5 protection to TCP sessions.

> @@ -749,29 +746,27 @@ static int tcp_v6_md5_hash_skb(char *md5_hash,
>  		daddr = &ip6h->daddr;
>  	}
>  
> -	hp = tcp_get_md5sig_pool();
> -	if (!hp)
> +	if (crypto_pool_get(tcp_md5_crypto_pool_id, (struct crypto_pool *)&hp))

&hp.base ? To avoid the cast

>  		goto clear_hash_noput;
> -	req = hp->md5_req;
>  
> -	if (crypto_ahash_init(req))
> +	if (crypto_ahash_init(hp.req))
>  		goto clear_hash;
>  
> -	if (tcp_v6_md5_hash_headers(hp, daddr, saddr, th, skb->len))
> +	if (tcp_v6_md5_hash_headers(&hp, daddr, saddr, th, skb->len))
>  		goto clear_hash;
> -	if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
> +	if (tcp_md5_hash_skb_data(&hp, skb, th->doff << 2))
>  		goto clear_hash;
> -	if (tcp_md5_hash_key(hp, key))
> +	if (tcp_md5_hash_key(&hp, key))
>  		goto clear_hash;
> -	ahash_request_set_crypt(req, NULL, md5_hash, 0);
> -	if (crypto_ahash_final(req))
> +	ahash_request_set_crypt(hp.req, NULL, md5_hash, 0);
> +	if (crypto_ahash_final(hp.req))
>  		goto clear_hash;
>  
> -	tcp_put_md5sig_pool();
> +	crypto_pool_put();
>  	return 0;
>  
>  clear_hash:
> -	tcp_put_md5sig_pool();
> +	crypto_pool_put();
>  clear_hash_noput:
>  	memset(md5_hash, 0, 16);
>  	return 1;