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From: Linus Torvalds <torvalds@linux-foundation.org>
To: Herbert Xu <herbert@gondor.hengli.com.au>
Cc: "David S. Miller" <davem@davemloft.net>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Linux Crypto Mailing List <linux-crypto@vger.kernel.org>
Subject: Re: Crypto Update for 2.6.38
Date: Thu, 6 Jan 2011 14:13:17 -0800
Message-ID: <AANLkTi=fggNhMm1LpOzzZ0_ofaU6w=ahX8SMGgFkHCui@mail.gmail.com> (raw)
In-Reply-To: <20110106213932.GA26538@gondor.apana.org.au>

On Thu, Jan 6, 2011 at 1:39 PM, Herbert Xu <herbert@gondor.hengli.com.au> wrote:
> On Thu, Jan 06, 2011 at 01:23:19PM -0800, Linus Torvalds wrote:
>>
>> Explanations of interface. Code. Who uses it? What are the actual
>> performance benefits on real code?
>
> You snipped out the bit in my reply where I expanded on it:

You didn't expand on it AT ALL.

You just mentioned "the interface". I haven't seen WHAT THAT INTERFACE IS!

How hard is that to understand?

> Here is the original cover email for the patches:

Ok, this is more like it. This is roughly what I wanted to see:

> : Here is a sample hash program (note that these only illustrate
> : what the interface looks like and are not meant to be good examples
> : of coding :)

But I'm still missing the part where you show that there is any actual
use case that makes sense, and that actually improves performance.
Maybe it's been posted somewhere else, but the thing is, you're asking
_me_ to pull, and as a result you need to convince _me_ that this is a
good idea. So if it's been posted/discussed extensively elsewhere,
please point to those discussions.

I really don't like adding interfaces that don't have hard uses
associated with them. We've done it in the past, and it tends to be a
morass and a bad idea. That's been true even when the idea has been my
own, and thus obviously genius-level and clearly the RightThing(tm),
like "splice()". And it's why I push back on new interfaces when I see
them.

Btw, it doesn't have to be about performance per se. Does this allow
people to use keys without actually _seeing_ those keys? Your example
implies that that is not the case, but that's actually one of the few
reasons to actually support a kernel crypto interface - the ability to
have private personal keys around, but not having to actually let
possibly untrusted programs see them.

For example of why something like that matters, I can well see myself
using some program to encrypt things. But maybe I don't trust that
program enough to give it my actual private keys. In that case, kernel
support is a real feature.

But in your example, it looks like you just give it the key. Which to
me means that you're totally missing one of the major reasons for
having a separate protection domain.

And that makes me think that the interface is bad. And that's why it's
a big change to go from "internal kernel crypto interface" to "actual
user-space interface to the kernel crypto engine". The first one can
be fixed. The second one cannot.

So I'm not necessarily hung up on "performance", but I am hung up on
"there needs to be a point", and "the interface needs to be
-correct-". Performance would be one such point. Not just 'the
hardware is there'. I know the hardware exists, but I'm not at all
convinced that DMA with all the cacheflushing will ever actully be
faster the the CPU. And if it can, I want to hear about the real-world
situation where it actually is used.

                Linus

  reply index

Thread overview: 246+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-12-25  0:17 Crypto Update for 2.6.29 Herbert Xu
2008-12-25  0:20 ` Herbert Xu
2009-03-24  4:49   ` Crypto Update for 2.6.30 Herbert Xu
     [not found]   ` <20090324044932.GA18245@gondor.apana.org.au>
2009-04-02  6:14     ` Herbert Xu
2009-05-17 22:28       ` Herbert Xu
2009-05-31 13:12         ` Herbert Xu
2009-06-13  2:05     ` Crypto Update for 2.6.31 Herbert Xu
2009-06-21 14:09       ` Crypto Fixes " Herbert Xu
2009-09-02 22:03         ` Herbert Xu
2009-09-10 14:19       ` Crypto Update for 2.6.32 Herbert Xu
     [not found]       ` <20090910141905.GA17948@gondor.apana.org.au>
2009-10-20  6:54         ` Crypto Fixes " Herbert Xu
2009-10-20  7:26           ` Herbert Xu
2009-11-23 12:05             ` Herbert Xu
2009-12-30  2:12           ` Crypto Fixes for 2.6.33 Herbert Xu
2010-02-01 19:52             ` Herbert Xu
     [not found]             ` <20100201195204.GA6953@gondor.apana.org.au>
2010-03-05  7:10               ` Crypto Fixes for 2.6.34 Herbert Xu
     [not found]               ` <20100305071043.GA3548@gondor.apana.org.au>
2010-04-27 13:55                 ` Herbert Xu
2010-06-03 10:05                   ` Crypto Fixes for 2.6.35 Herbert Xu
2010-06-03 16:26                     ` Linus Torvalds
2010-06-03 21:56                       ` Herbert Xu
2010-07-16  2:26                     ` Herbert Xu
2010-07-22  5:50                       ` Herbert Xu
2010-07-23  5:17                         ` Lee Nipper
2010-07-23  7:27                           ` Herbert Xu
2010-07-23 13:17                             ` Lee Nipper
2010-09-03  6:00                         ` Herbert Xu
2010-09-03 11:07                           ` Crypto Fixes for 2.6.36 Herbert Xu
2010-12-15 11:50                             ` Crypto Fixes for 2.6.37 Herbert Xu
2010-12-15 20:40                               ` Linus Torvalds
2010-12-16  0:49                                 ` Herbert Xu
2010-12-16  0:58                                   ` Herbert Xu
2011-02-16  5:39                               ` Crypto Fixes for 2.6.38 Herbert Xu
     [not found]                               ` <20110216053911.GA10999@gondor.apana.org.au>
2011-03-28  7:13                                 ` Crypto Fixes for 2.6.39 Herbert Xu
2011-06-29 23:51                                   ` Crypto Fixes for 3.0 Herbert Xu
2011-10-21  8:22                                     ` Crypto Fixes for 3.1 Herbert Xu
2011-10-21  9:41                                       ` David Rientjes
2011-10-21 11:35                                         ` Herbert Xu
2011-11-10 23:00                                       ` Crypto Fixes for 3.2 Herbert Xu
2011-11-26  2:34                                         ` Herbert Xu
2012-01-26  2:43                                     ` Crypto Fixes for 3.3 Herbert Xu
2012-01-26  3:35                                       ` Linus Torvalds
2012-01-26  4:07                                         ` Herbert Xu
2012-01-26  4:16                                           ` Linus Torvalds
2012-02-14  3:35                                       ` Herbert Xu
2012-02-16  5:32                                         ` Herbert Xu
2012-03-03  5:36                                           ` Herbert Xu
2012-03-22  1:20                                       ` Crypto Fixes for 3.4 Herbert Xu
2012-04-02  9:45                                         ` Herbert Xu
2012-04-20 14:16                                           ` Herbert Xu
2012-06-11 13:00                                         ` Crypto Fixes for 3.5 Herbert Xu
2012-06-18  8:24                                           ` Herbert Xu
2012-08-23  8:32                                       ` Crypto Fixes for 3.6 Herbert Xu
2012-09-11  4:10                                         ` Herbert Xu
2012-11-09  9:30                                         ` Crypto Fixes for 3.7 Herbert Xu
2013-03-28  8:28                                           ` Crypto Fixes for 3.9 Herbert Xu
2013-03-28 13:05                                             ` Chaoxing Lin
2013-03-28 13:52                                               ` Herbert Xu
2013-04-10  2:21                                             ` Herbert Xu
2013-04-22  0:34                                               ` Herbert Xu
2013-05-28  5:52                                             ` Crypto Fixes for 3.10 Herbert Xu
2013-06-10  9:05                                               ` Herbert Xu
2013-06-20 13:29                                                 ` Herbert Xu
2013-06-27 13:02                                                   ` Herbert Xu
2013-07-24  7:23                                             ` Crypto Fixes for 3.11 Herbert Xu
2013-09-13 11:30                                             ` Crypto Fixes for 3.12 Herbert Xu
2013-09-13 14:22                                               ` Linus Torvalds
2013-09-13 14:39                                                 ` Herbert Xu
2013-12-03 12:41                                             ` Crypto Fixes for 3.13 Herbert Xu
2013-12-09 11:57                                               ` Herbert Xu
2014-01-01  6:10                                                 ` Herbert Xu
2014-02-03 12:59                                                   ` Crypto Fixes for 3.14 Herbert Xu
2014-04-13 23:34                                                     ` Crypto Fixes for 3.15 Herbert Xu
2014-05-13 11:02                                                       ` Herbert Xu
2014-05-21 12:22                                                         ` Herbert Xu
2014-07-10  9:03                                                     ` Crypto Fixes for 3.16 Herbert Xu
2014-07-18 10:57                                                       ` Herbert Xu
2014-07-28 14:05                                                         ` Herbert Xu
2014-07-31 13:59                                                           ` Herbert Xu
2014-09-15 11:35                                                       ` Crypto Fixes for 3.17 Herbert Xu
2014-09-24 13:27                                                         ` Herbert Xu
2014-11-10  8:57                                                           ` Crypto Fixes for 3.18 Herbert Xu
2014-12-31  3:32                                                     ` Crypto Fixes for 3.19 Herbert Xu
2015-01-07  2:17                                                       ` Herbert Xu
2015-01-20  0:52                                                         ` Herbert Xu
2015-03-09  5:19                                                         ` Crypto Fixes for 4.0 Herbert Xu
2015-03-18  5:25                                                           ` Herbert Xu
2015-03-18 18:12                                                             ` Linus Torvalds
2015-04-25  8:03                                                         ` Crypto Fixes for 4.1 Herbert Xu
2015-05-05 10:06                                                           ` Herbert Xu
2015-05-11  5:56                                                             ` Herbert Xu
2015-05-20  6:54                                                               ` Herbert Xu
2015-05-22  4:05                                                                 ` Herbert Xu
2015-05-22 21:29                                                                   ` Linus Torvalds
2015-05-22 21:39                                                                     ` Herbert Xu
2015-05-26  8:43                                                                   ` Herbert Xu
2015-06-18  3:43                                                                     ` Herbert Xu
2010-09-04 10:45                           ` Crypto Fixes for 2.6.35 Chuck Ebbert
2010-09-04 12:22                             ` Herbert Xu
2010-11-13 12:59               ` Crypto Fixes for 2.6.37 Herbert Xu
2009-12-04 13:55     ` Crypto Update for 2.6.33 Herbert Xu
2010-02-26  0:49       ` Crypto Update for 2.6.34 Herbert Xu
2010-03-01  7:50         ` tip: origin tree boot crash Ingo Molnar
2010-03-01 14:55           ` Steffen Klassert
2010-03-03 14:42             ` Herbert Xu
2010-03-04  3:00               ` Ingo Molnar
2010-03-04  5:31                 ` Herbert Xu
2010-05-19  2:06         ` Crypto Update for 2.6.35 Herbert Xu
2010-05-21 10:44           ` Herbert Xu
2010-08-04 14:04             ` Crypto Update for 2.6.36 Herbert Xu
2010-10-24  6:16               ` Crypto Update for 2.6.37 Herbert Xu
     [not found]               ` <20101024061625.GA23715@gondor.apana.org.au>
2011-01-06  0:01                 ` Crypto Update for 2.6.38 Herbert Xu
2011-01-06 18:05                   ` Linus Torvalds
2011-01-06 21:16                     ` Herbert Xu
2011-01-06 21:23                       ` Linus Torvalds
2011-01-06 21:39                         ` Herbert Xu
2011-01-06 22:13                           ` Linus Torvalds [this message]
2011-01-06 22:30                             ` Herbert Xu
2011-01-06 22:33                               ` David Miller
2011-01-06 22:43                               ` Linus Torvalds
2011-01-06 22:53                                 ` Herbert Xu
2011-01-06 23:25                                   ` Linus Torvalds
2011-01-07  0:14                                     ` Herbert Xu
2011-01-07  2:43                                       ` David Miller
2011-01-07  3:04                                         ` Herbert Xu
2011-01-07  2:39                                   ` Pavel Roskin
2011-01-07  3:03                                     ` Herbert Xu
2011-01-07 12:04                             ` Neil Horman
2011-01-08 13:23                               ` Nikos Mavrogiannopoulos
2011-01-10 12:03                                 ` Neil Horman
2011-01-10 19:05                                   ` Dag Arne Osvik
2011-01-06 21:46                       ` Pavel Roskin
2011-01-06 21:49                         ` Herbert Xu
2011-01-06 23:02                         ` Mihai Donțu
2011-01-13  1:44                   ` Herbert Xu
2011-03-15 14:59                   ` Crypto Update for 2.6.39 Herbert Xu
2011-05-20 23:54                     ` Crypto Update for 2.6.40 Herbert Xu
2011-07-24  1:17                       ` Crypto Update for 3.1 Herbert Xu
2011-10-31  4:09                         ` Crypto Update for 3.2 Herbert Xu
2011-10-31 16:42                           ` Randy Dunlap
2011-10-31 17:16                             ` Linus Torvalds
2011-11-01  3:48                               ` Herbert Xu
2012-01-06  4:12                           ` Crypto Update for 3.3 Herbert Xu
2012-01-11 22:19                             ` Herbert Xu
2012-03-20  3:27                             ` Herbert Xu
2012-05-23  1:35                               ` Crypto Update for 3.5 Herbert Xu
2012-05-23 23:06                                 ` Linus Torvalds
2012-05-24  0:21                                   ` Herbert Xu
2012-05-24  8:36                                     ` Arnd Bergmann
2012-05-24  7:03                                   ` Linus Walleij
2012-07-25  8:41                                 ` Crypto Update for 3.6 Herbert Xu
2012-10-04  9:53                             ` Crypto Update for 3.7 Herbert Xu
2012-12-14 10:31                               ` Crypto Update for 3.8 Herbert Xu
2013-02-23  2:33                                 ` Crypto Update for 3.9 Herbert Xu
2013-05-02  1:47                                   ` Crypto Update for 3.10 Herbert Xu
2013-07-05  9:52                                     ` Crypto Update for 3.11 Herbert Xu
2013-09-07  3:55                                   ` Crypto Update for 3.12 Herbert Xu
2013-11-07  8:01                                     ` Crypto Update for 3.13 Herbert Xu
2013-11-12 16:41                                       ` Herbert Xu
2013-11-12 16:59                                         ` Borislav Petkov
2013-11-12 18:27                                           ` Herbert Xu
2013-11-19  2:21                                         ` [GIT] " Herbert Xu
2013-11-23  1:34                                         ` Herbert Xu
2013-11-23  1:40                                           ` Herbert Xu
2014-01-23 11:53                                       ` Crypto Update for 3.14 Herbert Xu
2014-04-01 10:00                                         ` Crypto Update for 3.15 Herbert Xu
2014-06-05  6:23                                           ` Crypto Update for 3.16 Herbert Xu
2014-06-08  2:56                                             ` Linus Torvalds
2014-06-08  4:55                                               ` Herbert Xu
2014-06-09  1:47                                               ` Steven Miao
2014-08-04 13:03                                             ` Crypto Update for 3.17 Herbert Xu
2014-10-07 13:18                                               ` Crypto Update for 3.18 Herbert Xu
2014-12-11 12:51                                                 ` Crypto Update for 3.19 Herbert Xu
2014-12-12 11:54                                                   ` Herbert Xu
2015-02-14  9:43                                                   ` Crypto Update for 3.20 Herbert Xu
2015-04-15  3:39                                                     ` Crypto Update for 4.1 Herbert Xu
2015-04-16  1:58                                                       ` Linus Torvalds
2015-04-16  2:37                                                         ` Linus Torvalds
2015-04-16  2:38                                                           ` Linus Torvalds
2015-04-16  2:42                                                             ` Herbert Xu
2015-04-16  2:49                                                               ` Linus Torvalds
2015-04-16  3:07                                                                 ` Herbert Xu
2015-04-16  3:34                                                                   ` Linus Torvalds
2015-04-23 19:27                                                                     ` Bobby Powers
2015-04-23 20:10                                                                       ` Ard Biesheuvel
2015-04-23 21:35                                                                         ` Bobby Powers
2015-04-24  6:37                                                                           ` [PATCH] crypto: x86/sha512_ssse3 - fixup for asm function prototype change Ard Biesheuvel
2015-04-24 12:20                                                                             ` Herbert Xu
2015-06-22  8:44                                                       ` Crypto Update for 4.2 Herbert Xu
2015-06-23  4:26                                                         ` Linus Torvalds
2015-06-23  4:32                                                           ` Herbert Xu
2015-06-24  2:11                                                         ` Linus Torvalds
2015-06-24 13:29                                                           ` Herbert Xu
2015-08-31 13:56                                                         ` Crypto Update for 4.3 Herbert Xu
2015-11-02  8:04                                                           ` Crypto Update for 4.4 Herbert Xu
2016-01-11 10:14                                                             ` Crypto Update for 4.5 Herbert Xu
2016-01-22 10:18                                                               ` Crypto Fixes " Herbert Xu
2016-02-01  8:31                                                                 ` Herbert Xu
2016-02-09 17:54                                                                 ` Herbert Xu
2016-03-23 13:09                                                                 ` Crypto Fixes for 4.6 Herbert Xu
2016-03-30  9:11                                                                 ` Herbert Xu
2016-04-14  6:25                                                                   ` Herbert Xu
2016-04-25 11:12                                                                     ` Herbert Xu
2016-04-20  9:49                                                                   ` Herbert Xu
2016-05-09  8:46                                                                   ` Herbert Xu
2016-05-13  5:59                                                                 ` Herbert Xu
2016-05-20  8:41                                                                   ` Crypto Fixes for 4.7 Herbert Xu
2016-05-30  6:31                                                                     ` Herbert Xu
2016-06-27  6:28                                                                     ` Herbert Xu
2016-08-16  8:48                                                                       ` Crypto Fixes for 4.8 Herbert Xu
2016-07-22  3:39                                                                     ` Crypto Fixes for 4.7 Herbert Xu
2016-07-23  3:10                                                                       ` Herbert Xu
2016-08-01  9:58                                                                 ` Crypto Fixes for 4.8 Herbert Xu
2016-08-23  9:51                                                                   ` Herbert Xu
2016-08-31 14:19                                                                     ` Herbert Xu
2016-09-05  9:33                                                                   ` Herbert Xu
2016-09-13 10:35                                                                     ` Herbert Xu
2016-09-19 11:21                                                                     ` Herbert Xu
2016-09-23 14:48                                                                     ` Herbert Xu
2016-10-25  2:34                                                                   ` Crypto Fixes for 4.9 Herbert Xu
2016-03-15  7:20                                                               ` Crypto Update for 4.6 Herbert Xu
2016-05-16  7:16                                                                 ` Crypto Update for 4.7 Herbert Xu
2016-07-25 10:53                                                                   ` Crypto Update for 4.8 Herbert Xu
2016-10-10  3:34                                                                     ` Crypto Update for 4.9 Herbert Xu
2015-06-26 10:22                                                     ` Crypto Fixes for 4.2 Herbert Xu
2015-06-26 20:07                                                       ` Linus Torvalds
2015-06-27  6:56                                                         ` Herbert Xu
2015-06-27 16:40                                                           ` Linus Torvalds
2015-06-29  7:32                                                             ` Herbert Xu
2015-06-30 13:51                                                       ` Herbert Xu
2015-07-13  4:08                                                         ` Herbert Xu
2015-08-03  7:16                                                           ` Herbert Xu
2015-08-17  8:27                                                             ` Herbert Xu
2015-09-08  9:25                                                       ` Crypto Fixes for 4.3 Herbert Xu
2015-09-16 10:30                                                         ` Herbert Xu
2015-09-26 20:01                                                           ` Herbert Xu
2015-10-13 12:17                                                             ` Herbert Xu
2015-10-13 17:23                                                               ` Linus Torvalds
2015-10-14  1:03                                                                 ` Herbert Xu
2015-10-14  2:00                                                                   ` Linus Torvalds
2015-10-14  2:38                                                                     ` Herbert Xu
2015-10-26 11:02                                                         ` Herbert Xu
2015-11-11  7:08                                                           ` Crypto Fixes for 4.4 Herbert Xu
2015-11-17  9:41                                                             ` Herbert Xu
2015-12-05  1:04                                                             ` Herbert Xu
2015-12-14  9:29                                                               ` Herbert Xu
2015-12-28 13:26                                                             ` Herbert Xu

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