[rdma-rdma:wip/leon-for-next 38/54] drivers/infiniband/hw/bng_re/bng_fw.c:278:2: error: call to undeclared function 'prefetch'; ISO C99 and later do not support implicit function declarations

[rdma-rdma:wip/leon-for-next 38/54] drivers/infiniband/hw/bng_re/bng_fw.c:278:2: error: call to undeclared function 'prefetch'; ISO C99 and later do not support implicit function declarations

[kernel test robot]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma.git wip/leon-for-next
head:   4022c7b6342a4d9a97e1e974e27efca95e79ed20
commit: 23669ca628b3c39dc3cc43a5b4b93b4b5ab4d58c [38/54] RDMA/bng_re: Add infrastructure for enabling Firmware channel
config: s390-allmodconfig (https://download.01.org/0day-ci/archive/20251125/202511250215.VMVtdDPm-lkp@intel.com/config)
compiler: clang version 18.1.8 (https://github.com/llvm/llvm-project 3b5b5c1ec4a3095ab096dd780e84d7ab81f3d7ff)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251125/202511250215.VMVtdDPm-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/202511250215.VMVtdDPm-lkp@intel.com/

All errors (new ones prefixed by >>):

>> drivers/infiniband/hw/bng_re/bng_fw.c:278:2: error: call to undeclared function 'prefetch'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
     278 |         prefetch(bng_re_get_qe(hwq, sw_cons, NULL));
         |         ^
   1 error generated.


vim +/prefetch +278 drivers/infiniband/hw/bng_re/bng_fw.c

   266	
   267	static irqreturn_t bng_re_creq_irq(int irq, void *dev_instance)
   268	{
   269		struct bng_re_rcfw *rcfw = dev_instance;
   270		struct bng_re_creq_ctx *creq;
   271		struct bng_re_hwq *hwq;
   272		u32 sw_cons;
   273	
   274		creq = &rcfw->creq;
   275		hwq = &creq->hwq;
   276		/* Prefetch the CREQ element */
   277		sw_cons = HWQ_CMP(hwq->cons, hwq);
 > 278		prefetch(bng_re_get_qe(hwq, sw_cons, NULL));
   279	
   280		tasklet_schedule(&creq->creq_tasklet);
   281	
   282		return IRQ_HANDLED;
   283	}
   284	

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