tree: https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git perf-wip head: 817022be1c1afcf3b0ca057ef25a8298c7a0a959 commit: 33801f83c8ad07e0c4fdf56362081b29882d5bf7 [30/33] block: change plugging to use a singly linked list config: arm-buildonly-randconfig-r002-20211015 (attached as .config) compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 6069a6a5049497a32a50a49661c2f4169078bdba) 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://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git/com... git remote add axboe-block https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git git fetch --no-tags axboe-block perf-wip git checkout 33801f83c8ad07e0c4fdf56362081b29882d5bf7 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 ARCH=arm If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All errors (new ones prefixed by >>): void blk_mq_plug_issue_direct(struct blk_plug *plug, bool from_schedule) ^ block/blk-mq.c:2168:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void blk_mq_plug_issue_direct(struct blk_plug *plug, bool from_schedule) ^ static } else if (same_queue_rq) { ^~~~~~~~~~~~~ block/blk-mq.c:2598:7: note: uninitialized use occurs here if (first_rq) { ^~~~~~~~ block/blk-mq.c:2591:10: note: remove the 'if' if its condition is always true } else if (same_queue_rq) { ^~~~~~~~~~~~~~~~~~~ block/blk-mq.c:2580:27: note: initialize the variable 'first_rq' to silence this warning struct request *first_rq; ^ = NULL 2 errors generated. vim +/blk_mq_plug_issue_direct +2168 block/blk-mq.c 2167 2169 { 2170 struct blk_mq_hw_ctx *hctx = NULL; 2171 int queued = 0; 2172 int errors = 0; 2173 2174 while (!rq_list_empty(plug->mq_list)) { 2175 struct request *rq; 2176 blk_status_t ret; 2177 2178 rq = rq_list_pop(&plug->mq_list); 2179 2180 if (!hctx) 2181 hctx = rq->mq_hctx; 2182 else if (hctx != rq->mq_hctx && hctx->queue->mq_ops->commit_rqs) { 2183 trace_block_unplug(hctx->queue, queued, !from_schedule); 2184 hctx->queue->mq_ops->commit_rqs(hctx); 2185 queued = 0; 2186 hctx = rq->mq_hctx; 2187 } 2188 2189 ret = blk_mq_request_issue_directly(rq, 2190 rq_list_empty(plug->mq_list)); 2191 if (ret != BLK_STS_OK) { 2192 if (ret == BLK_STS_RESOURCE || 2193 ret == BLK_STS_DEV_RESOURCE) { 2194 blk_mq_request_bypass_insert(rq, false, 2195 rq_list_empty(plug->mq_list)); 2196 break; 2197 } 2198 blk_mq_end_request(rq, ret); 2199 errors++; 2200 } else 2201 queued++; 2202 } 2203 2204 /* 2205 * If we didn't flush the entire list, we could have told 2206 * the driver there was more coming, but that turned out to 2207 * be a lie. 2208 */ 2209 if ((!rq_list_empty(plug->mq_list) || errors) && 2210 hctx->queue->mq_ops->commit_rqs && queued) 2211 hctx->queue->mq_ops->commit_rqs(hctx); 2212 } 2213 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org