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Message-ID: <20140423055141.GA32284@intel.com>
Date: Wed, 23 Apr 2014 11:21:41 +0530
From: Vinod Koul <vinod.koul@...el.com>
To: Joel Fernandes <joelf@...com>
Cc: dan.j.williams@...el.com, nsekhar@...com,
dmaengine@...r.kernel.org,
davinci-linux-open-source@...ux.davincidsp.com,
Linux OMAP List <linux-omap@...r.kernel.org>,
Linux ARM Kernel List <linux-arm-kernel@...ts.infradead.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] dmaengine: edma: No need save/restore interrupt flags
during spin_lock in IRQ
On Thu, Apr 17, 2014 at 12:58:33AM -0500, Joel Fernandes wrote:
> The vchan lock in edma_callback is acquired in hard interrupt context. As
> interrupts are already disabled, there's no point in save/restoring interrupt
> mask bit or cpsr flags.
>
> Get rid of flags local variable and use spin_lock instead of spin_lock_irqsave.
Applied, thanks
--
~Vinod
>
> Signed-off-by: Joel Fernandes <joelf@...com>
> ---
> drivers/dma/edma.c | 9 ++++-----
> 1 file changed, 4 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/dma/edma.c b/drivers/dma/edma.c
> index 91849aa..25a75e2 100644
> --- a/drivers/dma/edma.c
> +++ b/drivers/dma/edma.c
> @@ -638,7 +638,6 @@ static void edma_callback(unsigned ch_num, u16 ch_status, void *data)
> struct edma_chan *echan = data;
> struct device *dev = echan->vchan.chan.device->dev;
> struct edma_desc *edesc;
> - unsigned long flags;
> struct edmacc_param p;
>
> edesc = echan->edesc;
> @@ -649,7 +648,7 @@ static void edma_callback(unsigned ch_num, u16 ch_status, void *data)
>
> switch (ch_status) {
> case EDMA_DMA_COMPLETE:
> - spin_lock_irqsave(&echan->vchan.lock, flags);
> + spin_lock(&echan->vchan.lock);
>
> if (edesc) {
> if (edesc->cyclic) {
> @@ -665,11 +664,11 @@ static void edma_callback(unsigned ch_num, u16 ch_status, void *data)
> }
> }
>
> - spin_unlock_irqrestore(&echan->vchan.lock, flags);
> + spin_unlock(&echan->vchan.lock);
>
> break;
> case EDMA_DMA_CC_ERROR:
> - spin_lock_irqsave(&echan->vchan.lock, flags);
> + spin_lock(&echan->vchan.lock);
>
> edma_read_slot(EDMA_CHAN_SLOT(echan->slot[0]), &p);
>
> @@ -700,7 +699,7 @@ static void edma_callback(unsigned ch_num, u16 ch_status, void *data)
> edma_trigger_channel(echan->ch_num);
> }
>
> - spin_unlock_irqrestore(&echan->vchan.lock, flags);
> + spin_unlock(&echan->vchan.lock);
>
> break;
> default:
> --
> 1.7.9.5
>
--
--
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