[bug report] mtd: nand: omap2: fix return value check in omap_nand_probe()

[Roger Quadros]

Boris,

On 10/08/16 16:48, Boris Brezillon wrote:
> Hi,
> 
> On Thu, 4 Aug 2016 10:05:09 +0300
> Roger Quadros <rogerq at ti.com> wrote:
> 
>> +Franklin
>>
>> On 03/08/16 15:32, Dan Carpenter wrote:
>>> Hello Wei Yongjun,
>>>
>>> The patch de3bfc4a1616: "mtd: nand: omap2: fix return value check in
>>> omap_nand_probe()" from Jul 14, 2016, leads to the following static
>>> checker warning:
>>>
>>> 	drivers/mtd/nand/omap2.c:2173 omap_nand_probe()
>>> 	error: 'info->dma' dereferencing possible ERR_PTR()
>>>
>>> drivers/mtd/nand/omap2.c
>>>   1921          case NAND_OMAP_PREFETCH_DMA:
>>>   1922                  dma_cap_zero(mask);
>>>   1923                  dma_cap_set(DMA_SLAVE, mask);
>>>   1924                  info->dma = dma_request_chan(pdev->dev.parent, "rxtx");
>>>   1925  
>>>   1926                  if (IS_ERR(info->dma)) {
>>>                                    ^^^^^^^^^
>>>   1927                          dev_err(&pdev->dev, "DMA engine request failed\n");
>>>   1928                          err = PTR_ERR(info->dma);
>>>   1929                          goto return_error;
>>>   1930                  } else {
>>>   1931                          struct dma_slave_config cfg;
>>>   1932  
>>>   1933                          memset(&cfg, 0, sizeof(cfg));
>>>   1934                          cfg.src_addr = info->phys_base;
>>>   1935                          cfg.dst_addr = info->phys_base;
>>>   1936                          cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
>>>   1937                          cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
>>>   1938                          cfg.src_maxburst = 16;
>>>   1939                          cfg.dst_maxburst = 16;
>>>   1940                          err = dmaengine_slave_config(info->dma, &cfg);
>>>   1941                          if (err) {
>>>   1942                                  dev_err(&pdev->dev, "DMA engine slave config failed: %d\n",
>>>   1943                                          err);
>>>   1944                                  goto return_error;
>>>   1945                          }
>>>   1946                          nand_chip->read_buf   = omap_read_buf_dma_pref;
>>>   1947                          nand_chip->write_buf  = omap_write_buf_dma_pref;
>>>   1948                  }
>>>   1949                  break;
>>>   1950  
>>>
>>> [ snip ]
>>>
>>>   2170  
>>>   2171  return_error:
>>>   2172          if (info->dma)
>>>   2173                  dma_release_channel(info->dma);
>>>                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>>> We can't pass error pointers to dma_release_channel().  I can't compile
>>> this code though, so I'm not going to patch it.
> 
> 		if (!IS_ERR_OR_NULL(info->dma))
> 			dma_release_channel(info->dma);
> 
> Should do the trick.
> 
> Franklin, Roger, can you check if I'm right and send a fix?
> 
I'll send a patch by today. Thanks.

cheers,
-roger