Commit 214fc4e4 authored Sep 24, 2015 by Peter Ujfalusi Committed by Vinod Koul Sep 30, 2015

dmaengine: fix balance of privatecnt

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>

parent 40482e64

drivers/dma/dmaengine.c

+9 −1

Original line number	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);

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

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