Re: [PATCH v6 08/12] device core: Introduce DMA range map, supplanting dma_pfn_offset

[Dan Carpenter <dan.carpenter@oracle.com>]

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Hi Jim,

url:    https://github.com/0day-ci/linux/commits/Jim-Quinlan/PCI-brcmstb-enable-PCIe-for-STB-chips/20200702-053156
base:   https://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci.git next
config: arm-randconfig-m031-20200701 (attached as .config)
compiler: arm-linux-gnueabi-gcc (GCC) 9.3.0

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>

smatch warnings:
drivers/of/address.c:1012 of_dma_get_range() warn: passing zero to 'ERR_PTR'

# https://github.com/0day-ci/linux/commit/0c50b6db383883854419f10df0d79b663433f121
git remote add linux-review https://github.com/0day-ci/linux
git remote update linux-review
git checkout 0c50b6db383883854419f10df0d79b663433f121
vim +/ERR_PTR +1012 drivers/of/address.c

18308c94723e16 Grygorii Strashko 2014-04-24   955  /**
0c50b6db383883 Jim Quinlan       2020-07-01   956   * of_dma_get_range - Get DMA range info and put it into a map array
18308c94723e16 Grygorii Strashko 2014-04-24   957   * @np:		device node to get DMA range info
18308c94723e16 Grygorii Strashko 2014-04-24   958   *
18308c94723e16 Grygorii Strashko 2014-04-24   959   * Look in bottom up direction for the first "dma-ranges" property
0c50b6db383883 Jim Quinlan       2020-07-01   960   * and parse it.  Put the information into a DMA offset map array.
0c50b6db383883 Jim Quinlan       2020-07-01   961   *
18308c94723e16 Grygorii Strashko 2014-04-24   962   * dma-ranges format:
18308c94723e16 Grygorii Strashko 2014-04-24   963   *	DMA addr (dma_addr)	: naddr cells
18308c94723e16 Grygorii Strashko 2014-04-24   964   *	CPU addr (phys_addr_t)	: pna cells
18308c94723e16 Grygorii Strashko 2014-04-24   965   *	size			: nsize cells
18308c94723e16 Grygorii Strashko 2014-04-24   966   *
0c50b6db383883 Jim Quinlan       2020-07-01   967   * It returns -ENODEV if "dma-ranges" property was not found for this
0c50b6db383883 Jim Quinlan       2020-07-01   968   * device in the DT.
18308c94723e16 Grygorii Strashko 2014-04-24   969   */
0c50b6db383883 Jim Quinlan       2020-07-01   970  const struct bus_dma_region *of_dma_get_range(struct device_node *np)
18308c94723e16 Grygorii Strashko 2014-04-24   971  {
0c50b6db383883 Jim Quinlan       2020-07-01   972  	const struct bus_dma_region *map = NULL;
18308c94723e16 Grygorii Strashko 2014-04-24   973  	struct device_node *node = of_node_get(np);
0c50b6db383883 Jim Quinlan       2020-07-01   974  	struct of_range_parser parser;
18308c94723e16 Grygorii Strashko 2014-04-24   975  	const __be32 *ranges = NULL;
951d48855d86e7 Robin Murphy      2019-07-03   976  	bool found_dma_ranges = false;
7a8b64d17e3581 Rob Herring       2020-02-06   977  	struct of_range range;
0c50b6db383883 Jim Quinlan       2020-07-01   978  	int len, num_ranges = 0;
0c50b6db383883 Jim Quinlan       2020-07-01   979  	int ret = 0;
18308c94723e16 Grygorii Strashko 2014-04-24   980  
951d48855d86e7 Robin Murphy      2019-07-03   981  	while (node) {
18308c94723e16 Grygorii Strashko 2014-04-24   982  		ranges = of_get_property(node, "dma-ranges", &len);
18308c94723e16 Grygorii Strashko 2014-04-24   983  
18308c94723e16 Grygorii Strashko 2014-04-24   984  		/* Ignore empty ranges, they imply no translation required */
18308c94723e16 Grygorii Strashko 2014-04-24   985  		if (ranges && len > 0)
18308c94723e16 Grygorii Strashko 2014-04-24   986  			break;
18308c94723e16 Grygorii Strashko 2014-04-24   987  
951d48855d86e7 Robin Murphy      2019-07-03   988  		/* Once we find 'dma-ranges', then a missing one is an error */
951d48855d86e7 Robin Murphy      2019-07-03   989  		if (found_dma_ranges && !ranges) {
951d48855d86e7 Robin Murphy      2019-07-03   990  			ret = -ENODEV;
951d48855d86e7 Robin Murphy      2019-07-03   991  			goto out;
18308c94723e16 Grygorii Strashko 2014-04-24   992  		}
951d48855d86e7 Robin Murphy      2019-07-03   993  		found_dma_ranges = true;
18308c94723e16 Grygorii Strashko 2014-04-24   994  
951d48855d86e7 Robin Murphy      2019-07-03   995  		node = of_get_next_dma_parent(node);
951d48855d86e7 Robin Murphy      2019-07-03   996  	}
951d48855d86e7 Robin Murphy      2019-07-03   997  
951d48855d86e7 Robin Murphy      2019-07-03   998  	if (!node || !ranges) {
0d638a07d3a1e9 Rob Herring       2017-06-01   999  		pr_debug("no dma-ranges found for node(%pOF)\n", np);
18308c94723e16 Grygorii Strashko 2014-04-24  1000  		ret = -ENODEV;
18308c94723e16 Grygorii Strashko 2014-04-24  1001  		goto out;
18308c94723e16 Grygorii Strashko 2014-04-24  1002  	}
18308c94723e16 Grygorii Strashko 2014-04-24  1003  
7a8b64d17e3581 Rob Herring       2020-02-06  1004  	of_dma_range_parser_init(&parser, node);
7a8b64d17e3581 Rob Herring       2020-02-06  1005  
0c50b6db383883 Jim Quinlan       2020-07-01  1006  	for_each_of_range(&parser, &range)
0c50b6db383883 Jim Quinlan       2020-07-01  1007  		num_ranges++;
18308c94723e16 Grygorii Strashko 2014-04-24  1008  
0c50b6db383883 Jim Quinlan       2020-07-01  1009  	map = dma_create_offset_map(node, num_ranges);
                                                        ^^^
If this fails then "ret" is zero so the function returns NULL instead of
an error pointer.

18308c94723e16 Grygorii Strashko 2014-04-24  1010  out:
18308c94723e16 Grygorii Strashko 2014-04-24  1011  	of_node_put(node);
0c50b6db383883 Jim Quinlan       2020-07-01 @1012  	return map ? map : ERR_PTR(ret);
92ea637edea36e Santosh Shilimkar 2014-04-24  1014  

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

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