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dmaengine: fix balance of privatecnt

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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>
This commit is contained in:
Peter Ujfalusi 2015-09-24 12:03:35 +03:00 • committed by Vinod Koul
parent 40482e64b0
commit 214fc4e423
1 changed files with 9 additions and 1 deletions
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10
drivers/dma/dmaengine.c
View file

@ -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;