On Mon, Nov 12, 2012 at 4:33 AM, Jon Mason <jon.ma...@intel.com> wrote:
> device_control is an optional and not implemented in all DMA drivers.
> Any calls to these will result in a NULL pointer dereference. dmatest
> makes two of these calls when completing the kernel thread and removing
> the module. These are corrected by calling the dmaengine_device_control
> wrapper and checking for a non-existant device_control function pointer
> there.
>
> Signed-off-by: Jon Mason <jon.ma...@intel.com>
> CC: Vinod Koul <vinod.k...@intel.com>
> CC: Dan Williams <d...@fb.com>
> ---
> drivers/dma/dmatest.c | 4 ++--
> include/linux/dmaengine.h | 5 ++++-
> 2 files changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/dma/dmatest.c b/drivers/dma/dmatest.c
> index 24225f0..6ef9465 100644
> --- a/drivers/dma/dmatest.c
> +++ b/drivers/dma/dmatest.c
> @@ -499,7 +499,7 @@ err_srcs:
> thread_name, total_tests, failed_tests, ret);
>
> /* terminate all transfers on specified channels */
> - chan->device->device_control(chan, DMA_TERMINATE_ALL, 0);
> + dmaengine_terminate_all(chan);
> if (iterations > 0)
> while (!kthread_should_stop()) {
> DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wait_dmatest_exit);
> @@ -524,7 +524,7 @@ static void dmatest_cleanup_channel(struct dmatest_chan
> *dtc)
> }
>
> /* terminate all transfers on specified channels */
> - dtc->chan->device->device_control(dtc->chan, DMA_TERMINATE_ALL, 0);
> + dmaengine_terminate_all(dtc->chan);
>
> kfree(dtc);
> }
> diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
> index d3201e4..cf94e5f 100644
> --- a/include/linux/dmaengine.h
> +++ b/include/linux/dmaengine.h
> @@ -608,7 +608,10 @@ static inline int dmaengine_device_control(struct
> dma_chan *chan,
> enum dma_ctrl_cmd cmd,
> unsigned long arg)
> {
> - return chan->device->device_control(chan, cmd, arg);
> + if (chan->device->device_control)
> + return chan->device->device_control(chan, cmd, arg);
> + else
> + return -ENOSYS;
> }
Reviewed-by: Viresh Kumar <viresh.ku...@linaro.org>
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