[PATCH 08/10] dmaengine: img-mdc-dma: Use vchan_terminate_vdesc() instead of desc_free

From: Peter Ujfalusi
Date: Tue Nov 14 2017 - 09:33:18 EST


To avoid race with vchan_complete, use the race free way to terminate
running transfer.

Implement the device_synchronize callback to make sure that the terminated
descriptor is freed.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@xxxxxx>
---
drivers/dma/img-mdc-dma.c | 17 ++++++++++++-----
1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/drivers/dma/img-mdc-dma.c b/drivers/dma/img-mdc-dma.c
index 0391f930aecc..25cec9c243e1 100644
--- a/drivers/dma/img-mdc-dma.c
+++ b/drivers/dma/img-mdc-dma.c
@@ -694,7 +694,6 @@ static unsigned int mdc_get_new_events(struct mdc_chan *mchan)
static int mdc_terminate_all(struct dma_chan *chan)
{
struct mdc_chan *mchan = to_mdc_chan(chan);
- struct mdc_tx_desc *mdesc;
unsigned long flags;
LIST_HEAD(head);

@@ -703,21 +702,28 @@ static int mdc_terminate_all(struct dma_chan *chan)
mdc_chan_writel(mchan, MDC_CONTROL_AND_STATUS_CANCEL,
MDC_CONTROL_AND_STATUS);

- mdesc = mchan->desc;
- mchan->desc = NULL;
+ if (mchan->desc) {
+ vchan_terminate_vdesc(&mchan->desc->vd);
+ mchan->desc = NULL;
+ }
vchan_get_all_descriptors(&mchan->vc, &head);

mdc_get_new_events(mchan);

spin_unlock_irqrestore(&mchan->vc.lock, flags);

- if (mdesc)
- mdc_desc_free(&mdesc->vd);
vchan_dma_desc_free_list(&mchan->vc, &head);

return 0;
}

+static void mdc_synchronize(struct dma_chan *chan)
+{
+ struct mdc_chan *mchan = to_mdc_chan(chan);
+
+ vchan_synchronize(&mchan->vc);
+}
+
static int mdc_slave_config(struct dma_chan *chan,
struct dma_slave_config *config)
{
@@ -952,6 +958,7 @@ static int mdc_dma_probe(struct platform_device *pdev)
mdma->dma_dev.device_tx_status = mdc_tx_status;
mdma->dma_dev.device_issue_pending = mdc_issue_pending;
mdma->dma_dev.device_terminate_all = mdc_terminate_all;
+ mdma->dma_dev.device_synchronize = mdc_synchronize;
mdma->dma_dev.device_config = mdc_slave_config;

mdma->dma_dev.directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
--
Peter

Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki