Messages in this thread | | | Date | Tue, 25 Jan 2022 11:01:42 -0800 | From | "Paul E. McKenney" <> | Subject | Re: [ammarfaizi2-block:paulmck/linux-rcu/dev 80/85] kernel/rcu/srcutree.c:1168:27: warning: variable 'sdp' set but not used |
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On Tue, Jan 25, 2022 at 07:24:14PM +0800, kernel test robot wrote: > tree: https://github.com/ammarfaizi2/linux-block paulmck/linux-rcu/dev > head: 3cd375aa70d563fe8aa3e5f03280bdd8a334de45 > commit: 2c773bcaf4dd5031d0b2c980cc623ecfbcc6ab62 [80/85] squash! srcu: Make Tree SRCU able to operate without snp_node array > config: nds32-defconfig (https://download.01.org/0day-ci/archive/20220125/202201251933.iaAyduWp-lkp@intel.com/config) > compiler: nds32le-linux-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/ammarfaizi2/linux-block/commit/2c773bcaf4dd5031d0b2c980cc623ecfbcc6ab62 > git remote add ammarfaizi2-block https://github.com/ammarfaizi2/linux-block > git fetch --no-tags ammarfaizi2-block paulmck/linux-rcu/dev > git checkout 2c773bcaf4dd5031d0b2c980cc623ecfbcc6ab62 > # 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=nds32 SHELL=/bin/bash kernel/rcu/ > > 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/rcu/srcutree.c: In function 'srcu_barrier': > >> kernel/rcu/srcutree.c:1168:27: warning: variable 'sdp' set but not used [-Wunused-but-set-variable] > 1168 | struct srcu_data *sdp; > | ^~~
Fixed in e3ec4a4e8733 ("srcu: Make Tree SRCU able to operate without snp_node array").
Thank you for your testing efforts!
Thanx, Paul
> vim +/sdp +1168 kernel/rcu/srcutree.c > > 2c773bcaf4dd50 Paul E. McKenney 2022-01-24 1160 > dad81a2026841b Paul E. McKenney 2017-03-25 1161 /** > dad81a2026841b Paul E. McKenney 2017-03-25 1162 * srcu_barrier - Wait until all in-flight call_srcu() callbacks complete. > aacb5d91ab1bfb Paul E. McKenney 2018-10-28 1163 * @ssp: srcu_struct on which to wait for in-flight callbacks. > dad81a2026841b Paul E. McKenney 2017-03-25 1164 */ > aacb5d91ab1bfb Paul E. McKenney 2018-10-28 1165 void srcu_barrier(struct srcu_struct *ssp) > dad81a2026841b Paul E. McKenney 2017-03-25 1166 { > da915ad5cf25b5 Paul E. McKenney 2017-04-05 1167 int cpu; > da915ad5cf25b5 Paul E. McKenney 2017-04-05 @1168 struct srcu_data *sdp; > aacb5d91ab1bfb Paul E. McKenney 2018-10-28 1169 unsigned long s = rcu_seq_snap(&ssp->srcu_barrier_seq); > da915ad5cf25b5 Paul E. McKenney 2017-04-05 1170 > aacb5d91ab1bfb Paul E. McKenney 2018-10-28 1171 check_init_srcu_struct(ssp); > aacb5d91ab1bfb Paul E. McKenney 2018-10-28 1172 mutex_lock(&ssp->srcu_barrier_mutex); > aacb5d91ab1bfb Paul E. McKenney 2018-10-28 1173 if (rcu_seq_done(&ssp->srcu_barrier_seq, s)) { > da915ad5cf25b5 Paul E. McKenney 2017-04-05 1174 smp_mb(); /* Force ordering following return. */ > aacb5d91ab1bfb Paul E. McKenney 2018-10-28 1175 mutex_unlock(&ssp->srcu_barrier_mutex); > da915ad5cf25b5 Paul E. McKenney 2017-04-05 1176 return; /* Someone else did our work for us. */ > da915ad5cf25b5 Paul E. McKenney 2017-04-05 1177 } > aacb5d91ab1bfb Paul E. McKenney 2018-10-28 1178 rcu_seq_start(&ssp->srcu_barrier_seq); > aacb5d91ab1bfb Paul E. McKenney 2018-10-28 1179 init_completion(&ssp->srcu_barrier_completion); > da915ad5cf25b5 Paul E. McKenney 2017-04-05 1180 > da915ad5cf25b5 Paul E. McKenney 2017-04-05 1181 /* Initial count prevents reaching zero until all CBs are posted. */ > aacb5d91ab1bfb Paul E. McKenney 2018-10-28 1182 atomic_set(&ssp->srcu_barrier_cpu_cnt, 1); > da915ad5cf25b5 Paul E. McKenney 2017-04-05 1183 > 2c773bcaf4dd50 Paul E. McKenney 2022-01-24 1184 if (!smp_load_acquire(&ssp->srcu_size_state)) { > 2c773bcaf4dd50 Paul E. McKenney 2022-01-24 1185 srcu_barrier_one_cpu(ssp, per_cpu_ptr(ssp->sda, 0)); > 2c773bcaf4dd50 Paul E. McKenney 2022-01-24 1186 } else { > 2c773bcaf4dd50 Paul E. McKenney 2022-01-24 1187 > da915ad5cf25b5 Paul E. McKenney 2017-04-05 1188 /* > da915ad5cf25b5 Paul E. McKenney 2017-04-05 1189 * Each pass through this loop enqueues a callback, but only > da915ad5cf25b5 Paul E. McKenney 2017-04-05 1190 * on CPUs already having callbacks enqueued. Note that if > da915ad5cf25b5 Paul E. McKenney 2017-04-05 1191 * a CPU already has callbacks enqueue, it must have already > da915ad5cf25b5 Paul E. McKenney 2017-04-05 1192 * registered the need for a future grace period, so all we > da915ad5cf25b5 Paul E. McKenney 2017-04-05 1193 * need do is enqueue a callback that will use the same > da915ad5cf25b5 Paul E. McKenney 2017-04-05 1194 * grace period as the last callback already in the queue. > da915ad5cf25b5 Paul E. McKenney 2017-04-05 1195 */ > da915ad5cf25b5 Paul E. McKenney 2017-04-05 1196 for_each_possible_cpu(cpu) { > aacb5d91ab1bfb Paul E. McKenney 2018-10-28 1197 sdp = per_cpu_ptr(ssp->sda, cpu); > 2c773bcaf4dd50 Paul E. McKenney 2022-01-24 1198 srcu_barrier_one_cpu(ssp, per_cpu_ptr(ssp->sda, cpu)); > a602538e46c9c6 Paul E. McKenney 2017-04-28 1199 } > da915ad5cf25b5 Paul E. McKenney 2017-04-05 1200 } > da915ad5cf25b5 Paul E. McKenney 2017-04-05 1201 > da915ad5cf25b5 Paul E. McKenney 2017-04-05 1202 /* Remove the initial count, at which point reaching zero can happen. */ > aacb5d91ab1bfb Paul E. McKenney 2018-10-28 1203 if (atomic_dec_and_test(&ssp->srcu_barrier_cpu_cnt)) > aacb5d91ab1bfb Paul E. McKenney 2018-10-28 1204 complete(&ssp->srcu_barrier_completion); > aacb5d91ab1bfb Paul E. McKenney 2018-10-28 1205 wait_for_completion(&ssp->srcu_barrier_completion); > da915ad5cf25b5 Paul E. McKenney 2017-04-05 1206 > aacb5d91ab1bfb Paul E. McKenney 2018-10-28 1207 rcu_seq_end(&ssp->srcu_barrier_seq); > aacb5d91ab1bfb Paul E. McKenney 2018-10-28 1208 mutex_unlock(&ssp->srcu_barrier_mutex); > dad81a2026841b Paul E. McKenney 2017-03-25 1209 } > dad81a2026841b Paul E. McKenney 2017-03-25 1210 EXPORT_SYMBOL_GPL(srcu_barrier); > dad81a2026841b Paul E. McKenney 2017-03-25 1211 > > :::::: The code at line 1168 was first introduced by commit > :::::: da915ad5cf25b5f5d358dd3670c3378d8ae8c03e srcu: Parallelize callback handling > > :::::: TO: Paul E. McKenney <paulmck@linux.vnet.ibm.com> > :::::: CC: Paul E. McKenney <paulmck@linux.vnet.ibm.com> > > --- > 0-DAY CI Kernel Test Service, Intel Corporation > https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
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