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From: Dan Williams <>
	Li Yang <>, Timur Tabi <>
Subject: Re: [PATCH v7 6/8] fsl-dma: use spin_lock_bh to instead of spin_lock_irqsave
Date: Sun, 2 Sep 2012 01:41:18 -0700	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

On Thu, Aug 9, 2012 at 1:23 AM,  <> wrote:
> From: Qiang Liu <>
> The use of spin_lock_irqsave() is a stronger locking mechanism than is
> required throughout the driver. The minimum locking required should be
> used instead. Interrupts will be turned off and context will be saved,
> there is needless to use irqsave.
> Change all instances of spin_lock_irqsave() to spin_lock_bh().
> All manipulation of protected fields is done using tasklet context or
> weaker, which makes spin_lock_bh() the correct choice.

It seems you are coordinating fsl-dma copy and talitos xor operations.
 It looks like fsl-dma will be called through
talitos_process_pending()->dma_run_dependencies(), which is
potentially called in hard irq context.

This all comes back to the need to fix raid offload to manage the
channels explicitly rather than the current dependency chains.


  reply	other threads:[~2012-09-02  8:41 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-08-09  8:23 [PATCH v7 6/8] fsl-dma: use spin_lock_bh to instead of spin_lock_irqsave qiang.liu
2012-09-02  8:41 ` Dan Williams [this message]
2012-09-04 12:39   ` Liu Qiang-B32616

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