RE: [PATCH 6/8] fsl-dma: use spin_lock_bh to instead ofspin_lock_irqsave

[Liu Qiang-B32616]

Hi all,

Please ignore this one. Thanks.

> -----Original Message-----
> From: Liu Qiang-B32616
> Sent: Monday, August 06, 2012 6:15 PM
> To: linux-crypto@xxxxxxxxxxxxxxx; linuxppc-dev@xxxxxxxxxxxxxxxx;
> dan.j.williams@xxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> dan.j.williams@xxxxxxxxx; vinod.koul@xxxxxxxxx
> Cc: Phillips Kim-R1AAHA; herbert@xxxxxxxxxxxxxxxxxxxx;
> davem@xxxxxxxxxxxxx; arnd@xxxxxxxx; gregkh@xxxxxxxxxxxxxxxxxxx; Liu
> Qiang-B32616; Li Yang-R58472; Tabi Timur-B04825
> Subject: [PATCH 6/8] fsl-dma: use spin_lock_bh to instead of
> spin_lock_irqsave
> 
> From: Qiang Liu <qiang.liu@xxxxxxxxxxxxx>
> 
> 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.
> 
> Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
> Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
> Cc: Vinod Koul <vinod.koul@xxxxxxxxx>
> Cc: Li Yang <leoli@xxxxxxxxxxxxx>
> Cc: Timur Tabi <timur@xxxxxxxxxxxxx>
> Signed-off-by: Qiang Liu <qiang.liu@xxxxxxxxxxxxx>
> Acked-by: Ira W. Snyder <iws@xxxxxxxxxxxxxxxx>
> ---
>  drivers/dma/fsldma.c |   30 ++++++++++++------------------
>  1 files changed, 12 insertions(+), 18 deletions(-)
> 
> diff --git a/drivers/dma/fsldma.c b/drivers/dma/fsldma.c
> index 938d8c1..3f809df 100644
> --- a/drivers/dma/fsldma.c
> +++ b/drivers/dma/fsldma.c
> @@ -405,10 +405,9 @@ static dma_cookie_t fsl_dma_tx_submit(struct
> dma_async_tx_descriptor *tx)
>  	struct fsldma_chan *chan = to_fsl_chan(tx->chan);
>  	struct fsl_desc_sw *desc = tx_to_fsl_desc(tx);
>  	struct fsl_desc_sw *child;
> -	unsigned long flags;
>  	dma_cookie_t cookie;
> 
> -	spin_lock_irqsave(&chan->desc_lock, flags);
> +	spin_lock_bh(&chan->desc_lock);
> 
>  	/*
>  	 * assign cookies to all of the software descriptors
> @@ -421,7 +420,7 @@ static dma_cookie_t fsl_dma_tx_submit(struct
> dma_async_tx_descriptor *tx)
>  	/* put this transaction onto the tail of the pending queue */
>  	append_ld_queue(chan, desc);
> 
> -	spin_unlock_irqrestore(&chan->desc_lock, flags);
> +	spin_unlock_bh(&chan->desc_lock);
> 
>  	return cookie;
>  }
> @@ -761,15 +760,14 @@ static void fsldma_free_desc_list_reverse(struct
> fsldma_chan *chan,
>  static void fsl_dma_free_chan_resources(struct dma_chan *dchan)
>  {
>  	struct fsldma_chan *chan = to_fsl_chan(dchan);
> -	unsigned long flags;
> 
>  	chan_dbg(chan, "free all channel resources\n");
> -	spin_lock_irqsave(&chan->desc_lock, flags);
> +	spin_lock_bh(&chan->desc_lock);
>  	fsldma_cleanup_descriptors(chan);
>  	fsldma_free_desc_list(chan, &chan->ld_pending);
>  	fsldma_free_desc_list(chan, &chan->ld_running);
>  	fsldma_free_desc_list(chan, &chan->ld_completed);
> -	spin_unlock_irqrestore(&chan->desc_lock, flags);
> +	spin_unlock_bh(&chan->desc_lock);
> 
>  	dma_pool_destroy(chan->desc_pool);
>  	chan->desc_pool = NULL;
> @@ -988,7 +986,6 @@ static int fsl_dma_device_control(struct dma_chan
> *dchan,
>  {
>  	struct dma_slave_config *config;
>  	struct fsldma_chan *chan;
> -	unsigned long flags;
>  	int size;
> 
>  	if (!dchan)
> @@ -998,7 +995,7 @@ static int fsl_dma_device_control(struct dma_chan
> *dchan,
> 
>  	switch (cmd) {
>  	case DMA_TERMINATE_ALL:
> -		spin_lock_irqsave(&chan->desc_lock, flags);
> +		spin_lock_bh(&chan->desc_lock);
> 
>  		/* Halt the DMA engine */
>  		dma_halt(chan);
> @@ -1009,7 +1006,7 @@ static int fsl_dma_device_control(struct dma_chan
> *dchan,
>  		fsldma_free_desc_list(chan, &chan->ld_completed);
>  		chan->idle = true;
> 
> -		spin_unlock_irqrestore(&chan->desc_lock, flags);
> +		spin_unlock_bh(&chan->desc_lock);
>  		return 0;
> 
>  	case DMA_SLAVE_CONFIG:
> @@ -1051,11 +1048,10 @@ static int fsl_dma_device_control(struct dma_chan
> *dchan,
>  static void fsl_dma_memcpy_issue_pending(struct dma_chan *dchan)
>  {
>  	struct fsldma_chan *chan = to_fsl_chan(dchan);
> -	unsigned long flags;
> 
> -	spin_lock_irqsave(&chan->desc_lock, flags);
> +	spin_lock_bh(&chan->desc_lock);
>  	fsl_chan_xfer_ld_queue(chan);
> -	spin_unlock_irqrestore(&chan->desc_lock, flags);
> +	spin_unlock_bh(&chan->desc_lock);
>  }
> 
>  /**
> @@ -1068,15 +1064,14 @@ static enum dma_status fsl_tx_status(struct
> dma_chan *dchan,
>  {
>  	struct fsldma_chan *chan = to_fsl_chan(dchan);
>  	enum dma_status ret;
> -	unsigned long flags;
> 
>  	ret = dma_cookie_status(dchan, cookie, txstate);
>  	if (ret == DMA_SUCCESS)
>  		return ret;
> 
> -	spin_lock_irqsave(&chan->desc_lock, flags);
> +	spin_lock_bh(&chan->desc_lock);
>  	fsldma_cleanup_descriptors(chan);
> -	spin_unlock_irqrestore(&chan->desc_lock, flags);
> +	spin_unlock_bh(&chan->desc_lock);
> 
>  	return dma_cookie_status(dchan, cookie, txstate);
>  }
> @@ -1155,11 +1150,10 @@ static irqreturn_t fsldma_chan_irq(int irq, void
> *data)
>  static void dma_do_tasklet(unsigned long data)
>  {
>  	struct fsldma_chan *chan = (struct fsldma_chan *)data;
> -	unsigned long flags;
> 
>  	chan_dbg(chan, "tasklet entry\n");
> 
> -	spin_lock_irqsave(&chan->desc_lock, flags);
> +	spin_lock_bh(&chan->desc_lock);
> 
>  	/* the hardware is now idle and ready for more */
>  	chan->idle = true;
> @@ -1167,7 +1161,7 @@ static void dma_do_tasklet(unsigned long data)
>  	/* Run all cleanup for descriptors which have been completed */
>  	fsldma_cleanup_descriptors(chan);
> 
> -	spin_unlock_irqrestore(&chan->desc_lock, flags);
> +	spin_unlock_bh(&chan->desc_lock);
> 
>  	chan_dbg(chan, "tasklet exit\n");
>  }
> --
> 1.7.5.1


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