ASoC: fsl_asrc_dma: Fix dma_chan leak when config DMA channel failed

fsl_asrc_dma_hw_params() invokes dma_request_channel() or
fsl_asrc_get_dma_channel(), which returns a reference of the specified
dma_chan object to "pair->dma_chan[dir]" with increased refcnt.

The reference counting issue happens in one exception handling path of
fsl_asrc_dma_hw_params(). When config DMA channel failed for Back-End,
the function forgets to decrease the refcnt increased by
dma_request_channel() or fsl_asrc_get_dma_channel(), causing a refcnt
leak.

Fix this issue by calling dma_release_channel() when config DMA channel
failed.

Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
Link: https://lore.kernel.org/r/1590415966-52416-1-git-send-email-xiyuyang19@fudan.edu.cn
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/sound/soc/fsl/fsl_asrc_dma.c b/sound/soc/fsl/fsl_asrc_dma.c
index e5d1b21..d6a3fc5 100644 (file)
--- a/sound/soc/fsl/fsl_asrc_dma.c
+++ b/sound/soc/fsl/fsl_asrc_dma.c
@@ -261,6 +261,7 @@ static int fsl_asrc_dma_hw_params(struct snd_soc_component *component,
        ret = dmaengine_slave_config(pair->dma_chan[dir], &config_be);
        if (ret) {
                dev_err(dev, "failed to config DMA channel for Back-End\n");
+               dma_release_channel(pair->dma_chan[dir]);
                return ret;
        }