linux-kernel - Re: [patch] crypto, tcrypt: remove local_bh_disable/enable() around local_irq

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Message-ID: <20120927054417.GC22311@gondor.apana.org.au>
Date:	Wed, 26 Sep 2012 22:44:18 -0700
From:	Herbert Xu <herbert@...dor.apana.org.au>
To:	Suresh Siddha <suresh.b.siddha@...el.com>
Cc:	linux-kernel@...r.kernel.org, tim.c.chen@...ux.intel.com
Subject: Re: [patch] crypto, tcrypt: remove local_bh_disable/enable()
 around local_irq_disable/enable()

On Mon, Sep 17, 2012 at 10:37:26AM -0700, Suresh Siddha wrote:
> Ran into this while looking at some new crypto code using FPU
> hitting a WARN_ON_ONCE(!irq_fpu_usable()) in the kernel_fpu_begin()
> on a x86 kernel that uses the new eagerfpu model. In short, current eagerfpu
> changes return 0 for interrupted_kernel_fpu_idle() and the in_interrupt()
> thinks it is in the interrupt context because of the local_bh_disable().
> Thus resulting in the WARN_ON().
> 
> Remove the local_bh_disable/enable() calls around the existing
> local_irq_disable/enable() calls. local_irq_disable/enable() already
> disables the BH.
> 
>  [ If there are any other legitimate users calling kernel_fpu_begin() from
>    the process context but with BH disabled, then we can look into fixing the
>    irq_fpu_usable() in future. ]
> 
> Signed-off-by: Suresh Siddha <suresh.b.siddha@...el.com>
> Cc: Tim Chen <tim.c.chen@...ux.intel.com>

Patch applied.  Thanks!
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Email: Herbert Xu <herbert@...dor.apana.org.au>
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