On Tue, Dec 22, 2015 at 07:35:23PM -0800, Ashutosh Dixit wrote:
> This reverts commit e958e079e254 ("dmaengine: mic_x100: add missing
> spin_unlock").
>
> The above patch is incorrect. There is nothing wrong with the original
> code. The spin_lock is acquired in the "prep" functions and released
> in "submit".
And going by dmaengine sematics, I do not think that is entrely right.
A user may choose to prepare multiple desciptors and then sumbit later,
looking at code I do not see how that will work.
Please fix that
>
> Signed-off-by: Ashutosh Dixit <ashutosh.dixit@xxxxxxxxx>
> ---
> drivers/dma/mic_x100_dma.c | 15 +++++----------
> 1 file changed, 5 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/dma/mic_x100_dma.c b/drivers/dma/mic_x100_dma.c
> index cddfa8d..068e920 100644
> --- a/drivers/dma/mic_x100_dma.c
> +++ b/drivers/dma/mic_x100_dma.c
> @@ -317,7 +317,6 @@ mic_dma_prep_memcpy_lock(struct dma_chan *ch, dma_addr_t dma_dest,
> struct mic_dma_chan *mic_ch = to_mic_dma_chan(ch);
> struct device *dev = mic_dma_ch_to_device(mic_ch);
> int result;
> - struct dma_async_tx_descriptor *tx = NULL;
>
> if (!len && !flags)
> return NULL;
> @@ -325,13 +324,10 @@ mic_dma_prep_memcpy_lock(struct dma_chan *ch, dma_addr_t dma_dest,
> spin_lock(&mic_ch->prep_lock);
> result = mic_dma_do_dma(mic_ch, flags, dma_src, dma_dest, len);
> if (result >= 0)
> - tx = allocate_tx(mic_ch);
> -
> - if (!tx)
> - dev_err(dev, "Error enqueueing dma, error=%d\n", result);
> -
> + return allocate_tx(mic_ch);
> + dev_err(dev, "Error enqueueing dma, error=%d\n", result);
> spin_unlock(&mic_ch->prep_lock);
> - return tx;
> + return NULL;
> }
>
> static struct dma_async_tx_descriptor *
> @@ -339,14 +335,13 @@ mic_dma_prep_interrupt_lock(struct dma_chan *ch, unsigned long flags)
> {
> struct mic_dma_chan *mic_ch = to_mic_dma_chan(ch);
> int ret;
> - struct dma_async_tx_descriptor *tx = NULL;
>
> spin_lock(&mic_ch->prep_lock);
> ret = mic_dma_do_dma(mic_ch, flags, 0, 0, 0);
> if (!ret)
> - tx = allocate_tx(mic_ch);
> + return allocate_tx(mic_ch);
> spin_unlock(&mic_ch->prep_lock);
> - return tx;
> + return NULL;
> }
>
> /* Return the status of the transaction */
> --
> 2.0.0.rc3.2.g998f840
>
--
~Vinod
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