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staging: comedi: ni_660x: remove spinlock 'dma_cfg_lock'

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This spinlock is only used to protect changes to the private data 'dma_cfg'.

Before calling any function that would change the 'dma_cfg' the spinlock
'mite_channel_lock' is also locked. That spinlock is not unlocked until
after the 'dma_cfg' change.

Remove the redundant spinlock.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
H Hartley Sweeten 2016-03-22 11:10:51 -07:00 committed by Greg Kroah-Hartman
parent 4f2c3b2077
commit 80c67b37fc
1 changed files with 0 additions and 9 deletions
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9
drivers/staging/comedi/drivers/ni_660x.c
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@ -263,8 +263,6 @@ struct ni_660x_private {
spinlock_t mite_channel_lock;
/* prevents races between interrupt and comedi_poll */
spinlock_t interrupt_lock;
/* protects dma_cfg changes */
spinlock_t dma_cfg_lock;
unsigned int dma_cfg[NI660X_MAX_CHIPS];
unsigned int io_cfg[NI660X_NUM_PFI_CHANNELS];
u64 io_dir;
@ -313,9 +311,7 @@ static inline void ni_660x_set_dma_channel(struct comedi_device *dev,
{
struct ni_660x_private *devpriv = dev->private;
unsigned int chip = counter->chip_index;
unsigned long flags;
spin_lock_irqsave(&devpriv->dma_cfg_lock, flags);
devpriv->dma_cfg[chip] &= ~NI660X_DMA_CFG_SEL_MASK(mite_channel);
devpriv->dma_cfg[chip] |= NI660X_DMA_CFG_SEL(mite_channel,
counter->counter_index);
@ -323,7 +319,6 @@ static inline void ni_660x_set_dma_channel(struct comedi_device *dev,
NI660X_DMA_CFG_RESET(mite_channel),
NI660X_DMA_CFG);
mmiowb();
spin_unlock_irqrestore(&devpriv->dma_cfg_lock, flags);
}
static inline void ni_660x_unset_dma_channel(struct comedi_device *dev,
@ -332,14 +327,11 @@ static inline void ni_660x_unset_dma_channel(struct comedi_device *dev,
{
struct ni_660x_private *devpriv = dev->private;
unsigned int chip = counter->chip_index;
unsigned long flags;
spin_lock_irqsave(&devpriv->dma_cfg_lock, flags);
devpriv->dma_cfg[chip] &= ~NI660X_DMA_CFG_SEL_MASK(mite_channel);
devpriv->dma_cfg[chip] |= NI660X_DMA_CFG_SEL_NONE(mite_channel);
ni_660x_write(dev, chip, devpriv->dma_cfg[chip], NI660X_DMA_CFG);
mmiowb();
spin_unlock_irqrestore(&devpriv->dma_cfg_lock, flags);
}
static int ni_660x_request_mite_channel(struct comedi_device *dev,
@ -500,7 +492,6 @@ static int ni_660x_allocate_private(struct comedi_device *dev)
spin_lock_init(&devpriv->mite_channel_lock);
spin_lock_init(&devpriv->interrupt_lock);
spin_lock_init(&devpriv->dma_cfg_lock);
for (i = 0; i < NI660X_NUM_PFI_CHANNELS; ++i)
devpriv->io_cfg[i] = NI_660X_PFI_OUTPUT_COUNTER;