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From: Eric Dumazet <eric.dumazet@gmail.com>
To: Leonard Crestez <cdleonard@gmail.com>,
	Dmitry Safonov <0x7f454c46@gmail.com>,
	David Ahern <dsahern@kernel.org>, Shuah Khan <shuah@kernel.org>
Cc: Eric Dumazet <edumazet@google.com>,
	"David S. Miller" <davem@davemloft.net>,
	Herbert Xu <herbert@gondor.apana.org.au>,
	Kuniyuki Iwashima <kuniyu@amazon.co.jp>,
	Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
	Jakub Kicinski <kuba@kernel.org>,
	Yuchung Cheng <ycheng@google.com>,
	Francesco Ruggeri <fruggeri@arista.com>,
	Mat Martineau <mathew.j.martineau@linux.intel.com>,
	Christoph Paasch <cpaasch@apple.com>,
	Ivan Delalande <colona@arista.com>,
	Priyaranjan Jha <priyarjha@google.com>,
	Menglong Dong <dong.menglong@zte.com.cn>,
	netdev@vger.kernel.org, linux-crypto@vger.kernel.org,
	linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [RFCv3 05/15] tcp: authopt: Add crypto initialization
Date: Tue, 24 Aug 2021 16:02:32 -0700	[thread overview]
Message-ID: <72d126d8-1d44-de0c-fa1d-4362774ea3db@gmail.com> (raw)
In-Reply-To: <abb720b34b9eef1cc52ef68017334e27a2af83c6.1629840814.git.cdleonard@gmail.com>



On 8/24/21 2:34 PM, Leonard Crestez wrote:
> The crypto_shash API is used in order to compute packet signatures. The
> API comes with several unfortunate limitations:
> 
> 1) Allocating a crypto_shash can sleep and must be done in user context.
> 2) Packet signatures must be computed in softirq context
> 3) Packet signatures use dynamic "traffic keys" which require exclusive
> access to crypto_shash for crypto_setkey.
> 
> The solution is to allocate one crypto_shash for each possible cpu for
> each algorithm at setsockopt time. The per-cpu tfm is then borrowed from
> softirq context, signatures are computed and the tfm is returned.
> 
> The pool for each algorithm is reference counted, initialized at
> setsockopt time and released in tcp_authopt_key_info's rcu callback
> 
>

I don't know, why should we really care and try so hard to release
the tfm per cpu ?

I would simply allocate them at boot time.
This would avoid the expensive refcounting (potential false sharing)


  reply	other threads:[~2021-08-24 23:02 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-24 21:34 [RFCv3 00/15] tcp: Initial support for RFC5925 auth option Leonard Crestez
2021-08-24 21:34 ` [RFCv3 01/15] tcp: authopt: Initial support and key management Leonard Crestez
2021-08-31 19:04   ` Dmitry Safonov
2021-09-03 14:26     ` Leonard Crestez
2021-08-24 21:34 ` [RFCv3 02/15] docs: Add user documentation for tcp_authopt Leonard Crestez
2021-08-24 21:34 ` [RFCv3 03/15] selftests: Initial tcp_authopt test module Leonard Crestez
2021-08-24 21:34 ` [RFCv3 04/15] selftests: tcp_authopt: Initial sockopt manipulation Leonard Crestez
2021-08-24 21:34 ` [RFCv3 05/15] tcp: authopt: Add crypto initialization Leonard Crestez
2021-08-24 23:02   ` Eric Dumazet [this message]
2021-08-24 23:34   ` Eric Dumazet
2021-08-25  8:08     ` Herbert Xu
2021-08-25 14:55       ` Eric Dumazet
2021-08-25 16:04       ` Ard Biesheuvel
2021-08-25 16:31         ` Leonard Crestez
2021-08-25 16:35     ` Leonard Crestez
2021-08-25 17:55       ` Eric Dumazet
2021-08-25 18:56         ` Leonard Crestez
2021-08-24 21:34 ` [RFCv3 06/15] tcp: authopt: Compute packet signatures Leonard Crestez
2021-08-24 21:34 ` [RFCv3 07/15] tcp: authopt: Hook into tcp core Leonard Crestez
2021-08-24 22:59   ` Eric Dumazet
2021-08-25 16:32     ` Leonard Crestez
2021-08-24 21:34 ` [RFCv3 08/15] tcp: authopt: Add snmp counters Leonard Crestez
2021-08-24 21:34 ` [RFCv3 09/15] selftests: tcp_authopt: Test key address binding Leonard Crestez
2021-08-25  5:18   ` David Ahern
2021-08-25 16:37     ` Leonard Crestez
2021-08-24 21:34 ` [RFCv3 10/15] selftests: tcp_authopt: Capture and verify packets Leonard Crestez
2021-08-24 21:34 ` [RFCv3 11/15] selftests: Initial tcp_authopt support for nettest Leonard Crestez
2021-08-24 21:34 ` [RFCv3 12/15] selftests: Initial tcp_authopt support for fcnal-test Leonard Crestez
2021-08-24 21:34 ` [RFCv3 13/15] selftests: Add -t tcp_authopt option for fcnal-test.sh Leonard Crestez
2021-08-24 21:34 ` [RFCv3 14/15] tcp: authopt: Add key selection controls Leonard Crestez
2021-08-24 21:34 ` [RFCv3 15/15] selftests: tcp_authopt: Add tests for rollover Leonard Crestez

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