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Date:   Wed, 13 Apr 2022 10:52:59 +0800
From:   kernel test robot <lkp@intel.com>
To:     Thomas Gleixner <tglx@linutronix.de>,
        LKML <linux-kernel@vger.kernel.org>
Cc:     kbuild-all@lists.01.org, Christoph Hellwig <hch@infradead.org>,
        Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Subject: Re: [patch V4 1/2] smp: Rename flush_smp_call_function_from_idle()
Message-ID: <202204131011.m9M80Uip-lkp@intel.com>
References: <20220412204353.655068649@linutronix.de>
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In-Reply-To: <20220412204353.655068649@linutronix.de>
User-Agent: Mutt/1.10.1 (2018-07-13)
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Hi Thomas,

I love your patch! Perhaps something to improve:

[auto build test WARNING on tip/sched/core]
[also build test WARNING on hch-configfs/for-next linus/master linux/master v5.18-rc2 next-20220412]
[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]

url:    https://github.com/intel-lab-lkp/linux/commits/Thomas-Gleixner/smp-Make-softirq-handling-RT-friendly/20220413-045944
base:   https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git 089c02ae2771a14af2928c59c56abfb9b885a8d7
config: arc-defconfig (https://download.01.org/0day-ci/archive/20220413/202204131011.m9M80Uip-lkp@intel.com/config)
compiler: arc-elf-gcc (GCC) 11.2.0
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
        # https://github.com/intel-lab-lkp/linux/commit/7c7c3b99f3599eb409f237b32f330fa06bffcd5d
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Thomas-Gleixner/smp-Make-softirq-handling-RT-friendly/20220413-045944
        git checkout 7c7c3b99f3599eb409f237b32f330fa06bffcd5d
        # save the config file to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross O=build_dir ARCH=arc SHELL=/bin/bash

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

All warnings (new ones prefixed by >>):

>> kernel/smp.c:697:6: warning: no previous prototype for 'flush_smp_call_function_queue' [-Wmissing-prototypes]
     697 | void flush_smp_call_function_queue(void)
         |      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~


vim +/flush_smp_call_function_queue +697 kernel/smp.c

   683	
   684	
   685	/**
   686	 * flush_smp_call_function_queue - Flush pending smp-call-function callbacks
   687	 *				   from task context (idle, migration thread)
   688	 *
   689	 * When TIF_POLLING_NRFLAG is supported and a CPU is in idle and has it
   690	 * set, then remote CPUs can avoid sending IPIs and wake the idle CPU by
   691	 * setting TIF_NEED_RESCHED. The idle task on the woken up CPU has to
   692	 * handle queued SMP function calls before scheduling.
   693	 *
   694	 * The migration thread has to ensure that an eventually pending wakeup has
   695	 * been handled before it migrates a task.
   696	 */
 > 697	void flush_smp_call_function_queue(void)
   698	{
   699		unsigned long flags;
   700	
   701		if (llist_empty(this_cpu_ptr(&call_single_queue)))
   702			return;
   703	
   704		cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->idle, CFD_SEQ_NOCPU,
   705			      smp_processor_id(), CFD_SEQ_IDLE);
   706		local_irq_save(flags);
   707		__flush_smp_call_function_queue(true);
   708		if (local_softirq_pending())
   709			do_softirq();
   710	
   711		local_irq_restore(flags);
   712	}
   713	

-- 
0-DAY CI Kernel Test Service
https://01.org/lkp