dmatest: properly handle duplicate DMA channels
Update the the dmatest driver so that it handles duplicate DMA channels
properly.
When a DMA client is notified of an available DMA channel, it must check if it
has already allocated resources for that channel. If so, it should return
DMA_DUP. This can happen, for example, if a DMA driver calls
dma_async_device_register() more than once.
Acked-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
Signed-off-by: Timur Tabi <timur@freescale.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
diff --git a/drivers/dma/dmatest.c b/drivers/dma/dmatest.c
index a08d197..422500c 100644
--- a/drivers/dma/dmatest.c
+++ b/drivers/dma/dmatest.c
@@ -325,6 +325,11 @@
struct dmatest_thread *thread;
unsigned int i;
+ /* Have we already been told about this channel? */
+ list_for_each_entry(dtc, &dmatest_channels, node)
+ if (dtc->chan == chan)
+ return DMA_DUP;
+
dtc = kmalloc(sizeof(struct dmatest_chan), GFP_ATOMIC);
if (!dtc) {
pr_warning("dmatest: No memory for %s\n", chan->dev.bus_id);