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 for linux-mtd@lists.infradead.org; Wed, 10 Aug 2016 13:48:59 +0000
Date: Wed, 10 Aug 2016 15:48:34 +0200
From: Boris Brezillon <boris.brezillon@free-electrons.com>
To: Roger Quadros <rogerq@ti.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>,
 <yongjun_wei@trendmicro.com.cn>, "Cooper Jr., Franklin" <fcooper@ti.com>,
 Richard Weinberger <richard@nod.at>, linux-mtd@lists.infradead.org
Subject: Re: [bug report] mtd: nand: omap2: fix return value check in
 omap_nand_probe()
Message-ID: <20160810154834.5bd3c1f9@bbrezillon>
In-Reply-To: <bd02b812-5dc7-e431-bd8e-94b3edc706b1@ti.com>
References: <20160803123218.GA19033@mwanda>
 <bd02b812-5dc7-e431-bd8e-94b3edc706b1@ti.com>
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Hi,

On Thu, 4 Aug 2016 10:05:09 +0300
Roger Quadros <rogerq@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?