[openeuler:openEuler-1.0-LTS 1402/1402] block/blk-mq-sched.c:219:5: warning: no previous prototype for '__blk_mq_sched_dispatch_requests'

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

tree:   https://gitee.com/openeuler/kernel.git openEuler-1.0-LTS
head:   97f98c391a1fd153ae010a2faf73f9e03270da6e
commit: c1ea82c0ddde70d5998c2f547520afbee10bea2a [1402/1402] block: Limit number of items taken from the I/O scheduler in one go
config: x86_64-buildonly-randconfig-006-20250109 (https://download.01.org/0day-ci/archive/20250110/202501100428.rcoZkFtm-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250110/202501100428.rcoZkFtm-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/202501100428.rcoZkFtm-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> block/blk-mq-sched.c:219:5: warning: no previous prototype for '__blk_mq_sched_dispatch_requests' [-Wmissing-prototypes]
     219 | int __blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx)
         |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


vim +/__blk_mq_sched_dispatch_requests +219 block/blk-mq-sched.c

   218	
 > 219	int __blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx)
   220	{
   221		struct request_queue *q = hctx->queue;
   222		struct elevator_queue *e = q->elevator;
   223		const bool has_sched_dispatch = e && e->type->ops.mq.dispatch_request;
   224		int ret = 0;
   225		LIST_HEAD(rq_list);
   226	
   227		/*
   228		 * If we have previous entries on our dispatch list, grab them first for
   229		 * more fair dispatch.
   230		 */
   231		if (!list_empty_careful(&hctx->dispatch)) {
   232			spin_lock(&hctx->lock);
   233			if (!list_empty(&hctx->dispatch))
   234				list_splice_init(&hctx->dispatch, &rq_list);
   235			spin_unlock(&hctx->lock);
   236		}
   237	
   238		/*
   239		 * Only ask the scheduler for requests, if we didn't have residual
   240		 * requests from the dispatch list. This is to avoid the case where
   241		 * we only ever dispatch a fraction of the requests available because
   242		 * of low device queue depth. Once we pull requests out of the IO
   243		 * scheduler, we can no longer merge or sort them. So it's best to
   244		 * leave them there for as long as we can. Mark the hw queue as
   245		 * needing a restart in that case.
   246		 *
   247		 * We want to dispatch from the scheduler if there was nothing
   248		 * on the dispatch list or we were able to dispatch from the
   249		 * dispatch list.
   250		 */
   251		if (!list_empty(&rq_list)) {
   252			blk_mq_sched_mark_restart_hctx(hctx);
   253			if (blk_mq_dispatch_rq_list(q, &rq_list, false)) {
   254				if (has_sched_dispatch)
   255					ret = blk_mq_do_dispatch_sched(hctx);
   256				else
   257					ret = blk_mq_do_dispatch_ctx(hctx);
   258			}
   259		} else if (has_sched_dispatch) {
   260			ret = blk_mq_do_dispatch_sched(hctx);
   261		} else if (hctx->dispatch_busy) {
   262			/* dequeue request one by one from sw queue if queue is busy */
   263			ret = blk_mq_do_dispatch_ctx(hctx);
   264		} else {
   265			blk_mq_flush_busy_ctxs(hctx, &rq_list);
   266			blk_mq_dispatch_rq_list(q, &rq_list, false);
   267		}
   268	
   269		return ret;
   270	}
   271	

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