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Subject: Re: [PATCH] cryptoapi: Fix sleeping
From: Robert Love <rml@tech9.net>
To: Jeff Garzik <jgarzik@pobox.com>
Cc: Matt Mackall <mpm@selenic.com>, James Morris <jmorris@intercode.com.au>,
       "David S. Miller" <davem@redhat.com>,
       linux-kernel <linux-kernel@vger.kernel.org>
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On Wed, 2003-08-13 at 17:21, Jeff Garzik wrote:

> Do you really want to schedule inside preempt_disable() ?

in_atomic() includes a check for preempt_disable() ... that is actually
all it checks (the preempt_count).  So this fix prevents that.

This patch is interesting, though, because if right now we are
scheduling in the middle of per-CPU code there is a bug (regardless of
kernel preemption -- and with kernel preemption off, the in_atomic()
check might return false even though the code is accessing per-processor
data).

So I think what we really want is to just never call this crypto_yield()
thing when in any sort of critical section, which includes any
per-processor data.

	Robert Love