diff options
| author | Peter Ujfalusi <peter.ujfalusi@ti.com> | 2015-09-24 11:03:35 +0200 |
|---|---|---|
| committer | Vinod Koul <vinod.koul@intel.com> | 2015-09-30 10:00:08 +0200 |
| commit | 214fc4e423ff38b41b60db2209cf49b4e9a7209b (patch) | |
| tree | a66ae822330d8ee43275299d6669552bdfe6e48a /drivers/dma | |
| parent | dmaengine: sun4i: fix unsafe list iteration (diff) | |
| download | linux-214fc4e423ff38b41b60db2209cf49b4e9a7209b.tar.xz linux-214fc4e423ff38b41b60db2209cf49b4e9a7209b.zip | |
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>
Diffstat (limited to 'drivers/dma')
| -rw-r--r-- | drivers/dma/dmaengine.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c index 3ff284c8e3d5..09479d4be4db 100644 --- a/drivers/dma/dmaengine.c +++ b/drivers/dma/dmaengine.c @@ -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; |