[ammarfaizi2-block:paulmck/linux-rcu/dev 94/94] kernel/rcu/srcutree.c:313:6: warning: no previous prototype for function 'spin_lock_irqsave_ssp_contention'

[kernel test robot]

tree:   https://github.com/ammarfaizi2/linux-block paulmck/linux-rcu/dev
head:   903a93309e5a59497d3c178cabb67ecc6c843a69
commit: 903a93309e5a59497d3c178cabb67ecc6c843a69 [94/94] srcu: Add contention-triggered addition of srcu_node tree
config: arm-s5pv210_defconfig (https://download.01.org/0day-ci/archive/20220128/202201281920.PD1buizH-lkp@xxxxxxxxx/config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 33b45ee44b1f32ffdbc995e6fec806271b4b3ba4)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install arm cross compiling tool for clang build
        # apt-get install binutils-arm-linux-gnueabi
        # https://github.com/ammarfaizi2/linux-block/commit/903a93309e5a59497d3c178cabb67ecc6c843a69
        git remote add ammarfaizi2-block https://github.com/ammarfaizi2/linux-block
        git fetch --no-tags ammarfaizi2-block paulmck/linux-rcu/dev
        git checkout 903a93309e5a59497d3c178cabb67ecc6c843a69
        # save the config file to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm SHELL=/bin/bash kernel/rcu/

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>

All warnings (new ones prefixed by >>):

>> kernel/rcu/srcutree.c:313:6: warning: no previous prototype for function 'spin_lock_irqsave_ssp_contention' [-Wmissing-prototypes]
   void spin_lock_irqsave_ssp_contention(struct srcu_struct *ssp, unsigned long *flags)
        ^
   kernel/rcu/srcutree.c:313:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   void spin_lock_irqsave_ssp_contention(struct srcu_struct *ssp, unsigned long *flags)
   ^
   static 
   1 warning generated.


vim +/spin_lock_irqsave_ssp_contention +313 kernel/rcu/srcutree.c

   306	
   307	/*
   308	 * Acquire the specified srcu_struct structure's ->lock, but check for
   309	 * excessive contention, which results in initiation of a transition
   310	 * to SRCU_SIZE_BIG.  But only if the srcutree.convert_to_big module
   311	 * parameter permits this.
   312	 */
 > 313	void spin_lock_irqsave_ssp_contention(struct srcu_struct *ssp, unsigned long *flags)
   314	{
   315		unsigned long j;
   316	
   317		if (spin_trylock_irqsave_rcu_node(ssp, *flags))
   318			return;
   319		spin_lock_irqsave_rcu_node(ssp, *flags);
   320		if (!(convert_to_big & 0x10) || ssp->srcu_size_state)
   321			return;
   322		j = jiffies;
   323		if (ssp->srcu_size_jiffies != j) {
   324			ssp->srcu_size_jiffies = j;
   325			ssp->srcu_n_lock_retries = 0;
   326		}
   327		if (++ssp->srcu_n_lock_retries <= small_contention_lim)
   328			return;
   329		__srcu_transition_to_big(ssp);
   330	}
   331	

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0-DAY CI Kernel Test Service, Intel Corporation
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