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From: Herbert Xu <herbert@gondor.apana.org.au>
To: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Steffen Klassert <steffen.klassert@secunet.com>,
	andrea.parri@amarulasolutions.com, boqun.feng@gmail.com,
	paulmck@linux.ibm.com, peterz@infradead.org,
	linux-arch@vger.kernel.org, linux-crypto@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] padata: use smp_mb in padata_reorder to avoid orphaned padata jobs
Date: Tue, 16 Jul 2019 18:04:47 +0800	[thread overview]
Message-ID: <20190716100447.pdongriwwfxsuajf@gondor.apana.org.au> (raw)
In-Reply-To: <20190715161045.zqwgsp62uqjnvx3l@ca-dmjordan1.us.oracle.com>

On Mon, Jul 15, 2019 at 12:10:46PM -0400, Daniel Jordan wrote:
>
> I've been wrong before plenty of times, and there's nothing preventing this
> from being one of those times :) , but in this case I believe what I'm showing
> is correct.
> 
> The padata_do_serial call for a given job ensures padata_reorder runs on the
> CPU that the job hashed to in padata_do_parallel, which is not necessarily the
> same CPU as the one that padata_do_parallel itself ran on.

You're right.  I was taking the comment in the code at face value,
never trust comments :)

While looking at the code in question, I think it is seriously
broken.  For instance, padata_replace does not deal with async
crypto at all.  It would fail miserably if the underlying async
crypto held onto references to the old pd.

So we may have to restrict pcrypt to sync crypto only, which
would obviously mean that it can no longer use aesni.  Or we
will have to spend a lot of time to fix this up properly.

Cheers,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

  reply	other threads:[~2019-07-16 10:05 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-11 22:12 [PATCH] padata: use smp_mb in padata_reorder to avoid orphaned padata jobs Daniel Jordan
2019-07-12 10:06 ` Herbert Xu
2019-07-12 10:10   ` Steffen Klassert
2019-07-12 16:07     ` Daniel Jordan
2019-07-13  5:03       ` Herbert Xu
2019-07-15 16:10         ` Daniel Jordan
2019-07-16 10:04           ` Herbert Xu [this message]
2019-07-16 11:14             ` Steffen Klassert
2019-07-16 12:57               ` [PATCH] padata: Use RCU when fetching pd from do_serial Herbert Xu
2019-07-16 13:09                 ` Herbert Xu
2019-07-16 13:23                   ` [v2 PATCH] " Herbert Xu
2019-07-17  8:36                     ` Steffen Klassert
2019-07-17  8:50                       ` Herbert Xu
2019-07-17  8:28                   ` [PATCH] " Steffen Klassert
2019-07-17  8:47                     ` Herbert Xu
2019-07-17  8:53                       ` Steffen Klassert
2019-07-16 13:15                 ` Peter Zijlstra
2019-07-16 13:18                   ` Herbert Xu
2019-07-16 13:50                     ` Peter Zijlstra
2019-07-16 13:52                       ` Herbert Xu
2019-07-16 12:53       ` [PATCH] padata: use smp_mb in padata_reorder to avoid orphaned padata jobs Andrea Parri
2019-07-16 13:13         ` Peter Zijlstra
2019-07-16 15:01         ` Herbert Xu
2019-07-16 15:44           ` Daniel Jordan
2019-07-16 16:32             ` [PATCH v2] " Daniel Jordan
2019-07-17 11:11               ` [PATCH] padata: Replace delayed timer with immediate workqueue in padata_reorder Herbert Xu
2019-07-17 18:32                 ` Daniel Jordan
2019-07-18  3:31                   ` Herbert Xu
2019-07-18 14:27                     ` Daniel Jordan
2019-07-18 14:56                       ` Herbert Xu
2019-07-18 15:01                         ` [v2 PATCH] " Herbert Xu
2019-07-19 14:37                           ` Daniel Jordan
2019-07-19 14:55                             ` Herbert Xu
2019-07-19 19:04                               ` [PATCH] padata: purge get_cpu and reorder_via_wq from padata_do_serial Daniel Jordan
2019-07-26 12:36                                 ` Herbert Xu
2019-07-19 14:27                         ` [PATCH] padata: Replace delayed timer with immediate workqueue in padata_reorder Daniel Jordan
2019-07-17 23:21                 ` Daniel Jordan
2019-07-18  3:30                   ` Herbert Xu
2019-07-18 14:25                     ` Daniel Jordan
2019-07-18 14:49                       ` Herbert Xu
2019-07-19 14:21                         ` Daniel Jordan
2019-07-18  5:42               ` [PATCH v2] padata: use smp_mb in padata_reorder to avoid orphaned padata jobs Herbert Xu

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