[block:for-5.6/block-test 12/12] block/blk-mq-tag.c:135:2: error: implicit declaration of function 'cpus_read_lock'

[block:for-5.6/block-test 12/12] block/blk-mq-tag.c:135:2: error: implicit declaration of function 'cpus_read_lock'

[kbuild test robot]

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tree:   https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git for-5.6/block-test
head:   584946919310652c384d95ee9d8a538ced9e62b7
commit: 584946919310652c384d95ee9d8a538ced9e62b7 [12/12] blk-mq: allocate tags in batches
config: mips-pnx8335_stb225_defconfig (attached as .config)
compiler: mipsel-linux-gcc (GCC) 5.5.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        git checkout 584946919310652c384d95ee9d8a538ced9e62b7
        # save the attached .config to linux build tree
        GCC_VERSION=5.5.0 make.cross ARCH=mips 

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

All errors (new ones prefixed by >>):

   block/blk-mq-tag.c: In function 'blk_mq_tag_flush_batches':
>> block/blk-mq-tag.c:135:2: error: implicit declaration of function 'cpus_read_lock' [-Werror=implicit-function-declaration]
     cpus_read_lock();
     ^
>> block/blk-mq-tag.c:141:2: error: implicit declaration of function 'cpus_read_unlock' [-Werror=implicit-function-declaration]
     cpus_read_unlock();
     ^
   cc1: some warnings being treated as errors

vim +/cpus_read_lock +135 block/blk-mq-tag.c

   128	
   129	static void blk_mq_tag_flush_batches(struct blk_mq_hw_ctx *hctx)
   130	{
   131		int cpu, err;
   132	
   133		if (atomic_cmpxchg(&hctx->flush_pending, 0, hctx->nr_ctx))
   134			return;
 > 135		cpus_read_lock();
   136		for_each_cpu(cpu, hctx->cpumask) {
   137			err = smp_call_function_single(cpu, ctx_flush_ipi, hctx, 0);
   138			if (err)
   139				atomic_dec(&hctx->flush_pending);
   140		}
 > 141		cpus_read_unlock();
   142	}
   143	

---
0-DAY kernel test infrastructure                 Open Source Technology Center
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org Intel Corporation

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