Re: [PATCH next] dma: Add devm_dma_request_chan()

[kernel test robot <lkp@intel.com>]

Hi Bence,

kernel test robot noticed the following build warnings:

[auto build test WARNING on next-20241220]

url:    https://github.com/intel-lab-lkp/linux/commits/Bence-Cs-k-s/dma-Add-devm_dma_request_chan/20241220-211523
base:   next-20241220
patch link:    https://lore.kernel.org/r/20241220131350.544009-1-csokas.bence%40prolan.hu
patch subject: [PATCH next] dma: Add devm_dma_request_chan()
config: x86_64-buildonly-randconfig-002-20241221 (https://download.01.org/0day-ci/archive/20241221/202412211953.UwS2Qw11-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241221/202412211953.UwS2Qw11-lkp@intel.com/reproduce)

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>
| Closes: https://lore.kernel.org/oe-kbuild-all/202412211953.UwS2Qw11-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> drivers/dma/dmaengine.c:944:18: warning: no previous prototype for 'devm_dma_request_chan' [-Wmissing-prototypes]
     944 | struct dma_chan *devm_dma_request_chan(struct device *dev, const char *name)
         |                  ^~~~~~~~~~~~~~~~~~~~~
   drivers/dma/dmaengine.c: In function 'devm_dma_request_chan':
>> drivers/dma/dmaengine.c:953:32: warning: passing argument 1 of 'PTR_ERR' makes pointer from integer without a cast [-Wint-conversion]
     953 |                 return PTR_ERR(ret);
         |                                ^~~
         |                                |
         |                                int
   In file included from arch/x86/include/asm/processor.h:36,
                    from include/linux/sched.h:13,
                    from include/linux/ratelimit.h:6,
                    from include/linux/dev_printk.h:16,
                    from include/linux/device.h:15,
                    from include/linux/platform_device.h:13,
                    from drivers/dma/dmaengine.c:34:
   include/linux/err.h:52:61: note: expected 'const void *' but argument is of type 'int'
      52 | static inline long __must_check PTR_ERR(__force const void *ptr)
         |                                                 ~~~~~~~~~~~~^~~
>> drivers/dma/dmaengine.c:953:24: warning: returning 'long int' from a function with return type 'struct dma_chan *' makes pointer from integer without a cast [-Wint-conversion]
     953 |                 return PTR_ERR(ret);
         |                        ^~~~~~~~~~~~


vim +/devm_dma_request_chan +944 drivers/dma/dmaengine.c

   933	
   934	/**
   935	 * devm_dma_request_chan - try to allocate an exclusive slave channel
   936	 * @dev:	pointer to client device structure
   937	 * @name:	slave channel name
   938	 *
   939	 * Returns pointer to appropriate DMA channel on success or an error pointer.
   940	 *
   941	 * The operation is managed and will be undone on driver detach.
   942	 */
   943	
 > 944	struct dma_chan *devm_dma_request_chan(struct device *dev, const char *name)
   945	{
   946		struct dma_chan *chan = dma_request_chan(dev, name);
   947		int ret = 0;
   948	
   949		if (!IS_ERR(chan))
   950			ret = devm_add_action_or_reset(dev, dmaenginem_release_channel, chan);
   951	
   952		if (ret)
 > 953			return PTR_ERR(ret);
   954	
   955		return chan;
   956	}
   957	EXPORT_SYMBOL_GPL(devm_dma_request_chan);
   958	

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