dmaengine: fix balance of privatecnt (214fc4e4) · Commits · e / devices / android_kernel_teracube_2e

dma_release_channel() decrements privatecnt counter and almost all dma_get* function increments it with the exception of dma_get_slave_channel(). In most cases this does not cause issue since normally the channel is not requested and released, but if a driver requests DMA channel via dma_get_slave_channel() and releases the channel the privatecnt will be unbalanced and this will prevent for example getting channel for memcpy. Signed-off-by:

Peter Ujfalusi <peter.ujfalusi@ti.com> Signed-off-by:

Vinod Koul <vinod.koul@intel.com>

drivers/dma/dmaengine.c

+9 −1

Original line number	Original line	Diff line number	Diff line
	@@ -554,10 +554,18 @@ struct dma_chan dma_get_slave_channel(struct dma_chan chan)
	mutex_lock(&dma_list_mutex);		mutex_lock(&dma_list_mutex);

	if (chan->client_count == 0) {		if (chan->client_count == 0) {
			struct dma_device *device = chan->device;

			dma_cap_set(DMA_PRIVATE, device->cap_mask);
			device->privatecnt++;
	err = dma_chan_get(chan);		err = dma_chan_get(chan);
	if (err)		if (err) {
	pr_debug("%s: failed to get %s: (%d)\n",		pr_debug("%s: failed to get %s: (%d)\n",
	__func__, dma_chan_name(chan), err);		__func__, dma_chan_name(chan), err);
			chan = NULL;
			if (--device->privatecnt == 0)
			dma_cap_clear(DMA_PRIVATE, device->cap_mask);
			}
	} else		} else
	chan = NULL;		chan = NULL;