drivers/net/phy/phylink.c:2209:3: error: call to undeclared function 'unregister_fwnode_pcs_notifier'; ISO C99 and later do not support implicit function declarations

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

tree:   https://github.com/intel-lab-lkp/linux/commits/Christian-Marangi/net-phylink-keep-and-use-MAC-supported_interfaces-in-phylink-struct/20260615-212009
head:   10bf93a42ff6fa44dfd5bc9e6f71cca15ba1750a
commit: fc6fa24f5fd3fbc958ba44beefce3dea9843a70b net: phylink: support late PCS provider attach
date:   13 hours ago
config: x86_64-kexec (https://download.01.org/0day-ci/archive/20260616/202606160351.gbTsXg5I-lkp@intel.com/config)
compiler: clang version 22.0.0git (https://github.com/llvm/llvm-project f43d6834093b19baf79beda8c0337ab020ac5f17)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260616/202606160351.gbTsXg5I-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/202606160351.gbTsXg5I-lkp@intel.com/

All errors (new ones prefixed by >>):

   drivers/net/phy/phylink.c:2083:34: warning: variable 'pl' is uninitialized when used here [-Wuninitialized]
    2083 |         if (config->num_possible_pcs && pl->mac_ops->mac_select_pcs) {
         |                                         ^~
   drivers/net/phy/phylink.c:2069:20: note: initialize the variable 'pl' to silence this warning
    2069 |         struct phylink *pl;
         |                           ^
         |                            = NULL
>> drivers/net/phy/phylink.c:2209:3: error: call to undeclared function 'unregister_fwnode_pcs_notifier'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
    2209 |                 unregister_fwnode_pcs_notifier(&pl->fwnode_pcs_nb);
         |                 ^
   drivers/net/phy/phylink.c:2209:3: note: did you mean 'register_fwnode_pcs_notifier'?
   include/linux/pcs/pcs.h:104:19: note: 'register_fwnode_pcs_notifier' declared here
     104 | static inline int register_fwnode_pcs_notifier(struct notifier_block *nb)
         |                   ^
   1 warning and 1 error generated.


vim +/unregister_fwnode_pcs_notifier +2209 drivers/net/phy/phylink.c

  2189	
  2190	/**
  2191	 * phylink_destroy() - cleanup and destroy the phylink instance
  2192	 * @pl: a pointer to a &struct phylink returned from phylink_create()
  2193	 *
  2194	 * Destroy a phylink instance. Any PHY that has been attached must have been
  2195	 * cleaned up via phylink_disconnect_phy() prior to calling this function.
  2196	 *
  2197	 * Note: the rtnl lock must not be held when calling this function.
  2198	 */
  2199	void phylink_destroy(struct phylink *pl)
  2200	{
  2201		struct phylink_pcs *pcs, *tmp;
  2202	
  2203		sfp_bus_del_upstream(pl->sfp_bus);
  2204		if (pl->link_gpio)
  2205			gpiod_put(pl->link_gpio);
  2206	
  2207		/* Unregister notifier for late PCS attach */
  2208		if (pl->fwnode_pcs_nb.notifier_call)
> 2209			unregister_fwnode_pcs_notifier(&pl->fwnode_pcs_nb);
  2210	
  2211		/* Drop link between PCS and phylink */
  2212		list_for_each_entry(pcs, &pl->pcs_list, list)
  2213			pcs->phylink = NULL;
  2214	
  2215		/* Remove every PCS from phylink PCS list */
  2216		list_for_each_entry_safe(pcs, tmp, &pl->pcs_list, list)
  2217			list_del(&pcs->list);
  2218	
  2219		cancel_work_sync(&pl->resolve);
  2220		kfree(pl);
  2221	}
  2222	EXPORT_SYMBOL_GPL(phylink_destroy);
  2223	

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