[linux-next:master 3454/5042] drivers/dma/fsl-edma-main.c:133 fsl_edma_xlate() warn: inconsistent returns '&fsl_edma->fsl_edma_mutex'.

[linux-next:master 3454/5042] drivers/dma/fsl-edma-main.c:133 fsl_edma_xlate() warn: inconsistent returns '&fsl_edma->fsl_edma_mutex'.

[Dan Carpenter]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
head:   6ebf211bb11dfc004a2ff73a9de5386fa309c430
commit: 6aa60f79e6794bbbc571ea4e0501b9fcc26026e2 [3454/5042] dmaengine: fsl-edma: add safety check for 'srcid'
config: i386-randconfig-141-20240411 (https://download.01.org/0day-ci/archive/20240411/202404110915.riwV3ZAC-lkp@intel.com/config)
compiler: gcc-13 (Ubuntu 13.2.0-4ubuntu3) 13.2.0

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
| Closes: https://lore.kernel.org/r/202404110915.riwV3ZAC-lkp@intel.com/

smatch warnings:
drivers/dma/fsl-edma-main.c:133 fsl_edma_xlate() warn: inconsistent returns '&fsl_edma->fsl_edma_mutex'.

vim +133 drivers/dma/fsl-edma-main.c

d6be34fbd39b7d drivers/dma/fsl-edma.c      Jingchang Lu 2014-02-18   96  static struct dma_chan *fsl_edma_xlate(struct of_phandle_args *dma_spec,
d6be34fbd39b7d drivers/dma/fsl-edma.c      Jingchang Lu 2014-02-18   97  		struct of_dma *ofdma)
d6be34fbd39b7d drivers/dma/fsl-edma.c      Jingchang Lu 2014-02-18   98  {
d6be34fbd39b7d drivers/dma/fsl-edma.c      Jingchang Lu 2014-02-18   99  	struct fsl_edma_engine *fsl_edma = ofdma->of_dma_data;
178c81e58e9155 drivers/dma/fsl-edma.c      Jingchang Lu 2014-02-21  100  	struct dma_chan *chan, *_chan;
82d149b86d31e1 drivers/dma/fsl-edma.c      Yuan Yao     2015-10-30  101  	struct fsl_edma_chan *fsl_chan;
af802728e4ab07 drivers/dma/fsl-edma.c      Robin Gong   2019-06-25  102  	u32 dmamux_nr = fsl_edma->drvdata->dmamuxs;
af802728e4ab07 drivers/dma/fsl-edma.c      Robin Gong   2019-06-25  103  	unsigned long chans_per_mux = fsl_edma->n_chans / dmamux_nr;
d6be34fbd39b7d drivers/dma/fsl-edma.c      Jingchang Lu 2014-02-18  104  
d6be34fbd39b7d drivers/dma/fsl-edma.c      Jingchang Lu 2014-02-18  105  	if (dma_spec->args_count != 2)
d6be34fbd39b7d drivers/dma/fsl-edma.c      Jingchang Lu 2014-02-18  106  		return NULL;
d6be34fbd39b7d drivers/dma/fsl-edma.c      Jingchang Lu 2014-02-18  107  
d6be34fbd39b7d drivers/dma/fsl-edma.c      Jingchang Lu 2014-02-18  108  	mutex_lock(&fsl_edma->fsl_edma_mutex);
178c81e58e9155 drivers/dma/fsl-edma.c      Jingchang Lu 2014-02-21  109  	list_for_each_entry_safe(chan, _chan, &fsl_edma->dma_dev.channels, device_node) {
d6be34fbd39b7d drivers/dma/fsl-edma.c      Jingchang Lu 2014-02-18  110  		if (chan->client_count)
d6be34fbd39b7d drivers/dma/fsl-edma.c      Jingchang Lu 2014-02-18  111  			continue;
211bfef7c2bc8c drivers/dma/fsl-edma.c      Jingchang Lu 2014-07-01  112  		if ((chan->chan_id / chans_per_mux) == dma_spec->args[0]) {
d6be34fbd39b7d drivers/dma/fsl-edma.c      Jingchang Lu 2014-02-18  113  			chan = dma_get_slave_channel(chan);
d6be34fbd39b7d drivers/dma/fsl-edma.c      Jingchang Lu 2014-02-18  114  			if (chan) {
d6be34fbd39b7d drivers/dma/fsl-edma.c      Jingchang Lu 2014-02-18  115  				chan->device->privatecnt++;
82d149b86d31e1 drivers/dma/fsl-edma.c      Yuan Yao     2015-10-30  116  				fsl_chan = to_fsl_edma_chan(chan);
cee8cbfc7be8ff drivers/dma/fsl-edma-main.c Frank Li     2024-03-23  117  				fsl_chan->srcid = dma_spec->args[1];
6aa60f79e6794b drivers/dma/fsl-edma-main.c Frank Li     2024-03-23  118  
6aa60f79e6794b drivers/dma/fsl-edma-main.c Frank Li     2024-03-23  119  				if (!fsl_chan->srcid) {
6aa60f79e6794b drivers/dma/fsl-edma-main.c Frank Li     2024-03-23  120  					dev_err(&fsl_chan->pdev->dev, "Invalidate srcid %d\n",
6aa60f79e6794b drivers/dma/fsl-edma-main.c Frank Li     2024-03-23  121  						fsl_chan->srcid);

mutex_unlock(&fsl_edma->fsl_edma_mutex); before returning

6aa60f79e6794b drivers/dma/fsl-edma-main.c Frank Li     2024-03-23  122  					return NULL;
6aa60f79e6794b drivers/dma/fsl-edma-main.c Frank Li     2024-03-23  123  				}
6aa60f79e6794b drivers/dma/fsl-edma-main.c Frank Li     2024-03-23  124  
cee8cbfc7be8ff drivers/dma/fsl-edma-main.c Frank Li     2024-03-23  125  				fsl_edma_chan_mux(fsl_chan, fsl_chan->srcid,
82d149b86d31e1 drivers/dma/fsl-edma.c      Yuan Yao     2015-10-30  126  						true);
d6be34fbd39b7d drivers/dma/fsl-edma.c      Jingchang Lu 2014-02-18  127  				mutex_unlock(&fsl_edma->fsl_edma_mutex);
d6be34fbd39b7d drivers/dma/fsl-edma.c      Jingchang Lu 2014-02-18  128  				return chan;
d6be34fbd39b7d drivers/dma/fsl-edma.c      Jingchang Lu 2014-02-18  129  			}
d6be34fbd39b7d drivers/dma/fsl-edma.c      Jingchang Lu 2014-02-18  130  		}
d6be34fbd39b7d drivers/dma/fsl-edma.c      Jingchang Lu 2014-02-18  131  	}
d6be34fbd39b7d drivers/dma/fsl-edma.c      Jingchang Lu 2014-02-18  132  	mutex_unlock(&fsl_edma->fsl_edma_mutex);
d6be34fbd39b7d drivers/dma/fsl-edma.c      Jingchang Lu 2014-02-18 @133  	return NULL;
d6be34fbd39b7d drivers/dma/fsl-edma.c      Jingchang Lu 2014-02-18  134  }

-- 
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https://github.com/intel/lkp-tests/wiki