Re: [linux-next:master 3841/4021] kernel/workqueue.c:6798:32: error: passing 'const struct bus_type *' to parameter of type 'struct bus_type *' discards qualifiers

["Ricardo B. Marliere" <ricardo@marliere.net>]

On  5 Feb 15:15, kernel test robot wrote:
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
> head:   23e11d0318521e8693459b0e4d23aec614b3b68b
> commit: d412ace11144aa2bf692c7cf9778351efc15c827 [3841/4021] workqueue: make wq_subsys const
> config: i386-buildonly-randconfig-003-20240205 (https://download.01.org/0day-ci/archive/20240205/202402051505.kM9Rr3CJ-lkp@intel.com/config)
> compiler: clang version 17.0.6 (https://github.com/llvm/llvm-project 6009708b4367171ccdbf4b5905cb6a803753fe18)
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240205/202402051505.kM9Rr3CJ-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/202402051505.kM9Rr3CJ-lkp@intel.com/
> 
> Note: the linux-next/master HEAD 23e11d0318521e8693459b0e4d23aec614b3b68b builds fine.
>       It may have been fixed somewhere.
> 
> All errors (new ones prefixed by >>):
> 
> >> kernel/workqueue.c:6798:32: error: passing 'const struct bus_type *' to parameter of type 'struct bus_type *' discards qualifiers [-Werror,-Wincompatible-pointer-types-discards-qualifiers]
>     6798 |         err = subsys_virtual_register(&wq_subsys, NULL);
>          |                                       ^~~~~~~~~~
>    include/linux/device.h:77:46: note: passing argument to parameter 'subsys' here
>       77 | int subsys_virtual_register(struct bus_type *subsys,

I'm not sure how to flag this as invalid, since this is fixed already in
32f78abe59c7 ("driver core: bus: constantify subsys_register() calls")

>          |                                              ^
>    1 error generated.
> 
> 
> vim +6798 kernel/workqueue.c
> 
> b05a79280b346e Frederic Weisbecker 2015-04-27  6792  
> 6ba94429c8e7b8 Frederic Weisbecker 2015-04-02  6793  static int __init wq_sysfs_init(void)
> 2d3854a37e8b76 Rusty Russell       2008-11-05  6794  {
> 686f669780276d Greg Kroah-Hartman  2023-03-13  6795  	struct device *dev_root;
> b05a79280b346e Frederic Weisbecker 2015-04-27  6796  	int err;
> b05a79280b346e Frederic Weisbecker 2015-04-27  6797  
> b05a79280b346e Frederic Weisbecker 2015-04-27 @6798  	err = subsys_virtual_register(&wq_subsys, NULL);
> b05a79280b346e Frederic Weisbecker 2015-04-27  6799  	if (err)
> b05a79280b346e Frederic Weisbecker 2015-04-27  6800  		return err;
> b05a79280b346e Frederic Weisbecker 2015-04-27  6801  
> 686f669780276d Greg Kroah-Hartman  2023-03-13  6802  	dev_root = bus_get_dev_root(&wq_subsys);
> 686f669780276d Greg Kroah-Hartman  2023-03-13  6803  	if (dev_root) {
> fe28f631fa941f Waiman Long         2023-10-25  6804  		struct device_attribute *attr;
> fe28f631fa941f Waiman Long         2023-10-25  6805  
> fe28f631fa941f Waiman Long         2023-10-25  6806  		for (attr = wq_sysfs_cpumask_attrs; attr->attr.name; attr++) {
> fe28f631fa941f Waiman Long         2023-10-25  6807  			err = device_create_file(dev_root, attr);
> fe28f631fa941f Waiman Long         2023-10-25  6808  			if (err)
> fe28f631fa941f Waiman Long         2023-10-25  6809  				break;
> fe28f631fa941f Waiman Long         2023-10-25  6810  		}
> 686f669780276d Greg Kroah-Hartman  2023-03-13  6811  		put_device(dev_root);
> 686f669780276d Greg Kroah-Hartman  2023-03-13  6812  	}
> 686f669780276d Greg Kroah-Hartman  2023-03-13  6813  	return err;
> 2d3854a37e8b76 Rusty Russell       2008-11-05  6814  }
> 6ba94429c8e7b8 Frederic Weisbecker 2015-04-02  6815  core_initcall(wq_sysfs_init);
> 2d3854a37e8b76 Rusty Russell       2008-11-05  6816  
> 
> :::::: The code at line 6798 was first introduced by commit
> :::::: b05a79280b346eb24ddb73b39988398015291075 workqueue: Create low-level unbound workqueues cpumask
> 
> :::::: TO: Frederic Weisbecker <fweisbec@gmail.com>
> :::::: CC: Tejun Heo <tj@kernel.org>
> 
> -- 
> 0-DAY CI Kernel Test Service
> https://github.com/intel/lkp-tests/wiki