[PATCH v2 4/5] driver core: Add device probe log helper dev_warn_probe()

[kernel test robot]

Hi Dragan,

kernel test robot noticed the following build warnings:

[auto build test WARNING on rockchip/for-next]
[also build test WARNING on broonie-spi/for-next driver-core/driver-core-testing driver-core/driver-core-next driver-core/driver-core-linus linus/master v6.11 next-20240927]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Dragan-Simic/spi-rockchip-Perform-trivial-code-cleanups/20240928-121548
base:   https://git.kernel.org/pub/scm/linux/kernel/git/mmind/linux-rockchip.git for-next
patch link:    https://lore.kernel.org/r/2fd9a60e0efe906dc7a203cd652c8d0b7f932470.1727496560.git.dsimic%40manjaro.org
patch subject: [PATCH v2 4/5] driver core: Add device probe log helper dev_warn_probe()
config: openrisc-allnoconfig (https://download.01.org/0day-ci/archive/20240929/202409290956.jwLrcN1S-lkp@intel.com/config)
compiler: or1k-linux-gcc (GCC) 14.1.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240929/202409290956.jwLrcN1S-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 at intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202409290956.jwLrcN1S-lkp@intel.com/

All warnings (new ones prefixed by >>):

   drivers/base/core.c: In function 'dev_err_probe':
>> drivers/base/core.c:5055:1: warning: control reaches end of non-void function [-Wreturn-type]
    5055 | }
         | ^
   drivers/base/core.c: In function 'dev_warn_probe':
   drivers/base/core.c:5101:1: warning: control reaches end of non-void function [-Wreturn-type]
    5101 | }
         | ^


vim +5055 drivers/base/core.c

  5011	
  5012	/**
  5013	 * dev_err_probe - probe error check and log helper
  5014	 * @dev: the pointer to the struct device
  5015	 * @err: error value to test
  5016	 * @fmt: printf-style format string
  5017	 * @...: arguments as specified in the format string
  5018	 *
  5019	 * This helper implements common pattern present in probe functions for error
  5020	 * checking: print debug or error message depending if the error value is
  5021	 * -EPROBE_DEFER and propagate error upwards.
  5022	 * In case of -EPROBE_DEFER it sets also defer probe reason, which can be
  5023	 * checked later by reading devices_deferred debugfs attribute.
  5024	 * It replaces the following code sequence::
  5025	 *
  5026	 * 	if (err != -EPROBE_DEFER)
  5027	 * 		dev_err(dev, ...);
  5028	 * 	else
  5029	 * 		dev_dbg(dev, ...);
  5030	 * 	return err;
  5031	 *
  5032	 * with::
  5033	 *
  5034	 * 	return dev_err_probe(dev, err, ...);
  5035	 *
  5036	 * Using this helper in your probe function is totally fine even if @err
  5037	 * is known to never be -EPROBE_DEFER.
  5038	 * The benefit compared to a normal dev_err() is the standardized format
  5039	 * of the error code, which is emitted symbolically (i.e. you get "EAGAIN"
  5040	 * instead of "-35"), and having the error code returned allows more
  5041	 * compact error paths.
  5042	 *
  5043	 * Returns @err.
  5044	 */
  5045	int dev_err_probe(const struct device *dev, int err, const char *fmt, ...)
  5046	{
  5047		va_list args;
  5048	
  5049		va_start(args, fmt);
  5050	
  5051		/* Use dev_err() for logging when err doesn't equal -EPROBE_DEFER */
  5052		dev_probe_failed(dev, err, true, fmt, args);
  5053	
  5054		va_end(args);
> 5055	}
  5056	EXPORT_SYMBOL_GPL(dev_err_probe);
  5057	

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