From: Dan Williams <djbw@fb.com>
To: qiang.liu@freescale.com
Cc: linux-crypto@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
linux-kernel@vger.kernel.org, vinod.koul@intel.com,
kim.phillips@freescale.com, herbert@gondor.hengli.com.au,
davem@davemloft.net, arnd@arndb.de, gregkh@linuxfoundation.org,
Li Yang <leoli@freescale.com>, Timur Tabi <timur@freescale.com>
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: <CAA9_cmeFamCX1u+z3fP_gxAqe83JFbY9Beqpqgb-PjRoJ8BrWA@mail.gmail.com> (raw)
In-Reply-To: <1344500582-11110-1-git-send-email-qiang.liu@freescale.com>
On Thu, Aug 9, 2012 at 1:23 AM, <qiang.liu@freescale.com> wrote:
> From: Qiang Liu <qiang.liu@freescale.com>
>
> 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.
--
Dan
next prev parent 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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