drivers/md/raid5.c:7902 raid5_start_reshape() warn: statement has no effect 31

From: kernel test robot
Date: Wed Aug 12 2020 - 18:42:43 EST

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tree: config: i386-randconfig-m031-20200811 compiler: gcc-9
If you fix the issue, Reported-by: kernel
New smatch warnings:
drivers/md/raid5.c:7902
Old smatch warnings:
drivers/md/raid5.c:6693 drivers/md/raid5.c:6913 drivers/md/raid5.c:7978
vim +7902 drivers/md/raid5.c

63c70c4f3a30e77 NeilBrown fd01b88c75a7180 NeilBrown 63c70c4f3a30e77 NeilBrown d1688a6d5515f19 NeilBrown 3cb03002000f133 NeilBrown 63c70c4f3a30e77 NeilBrown c04be0aa82ff535 NeilBrown 63c70c4f3a30e77 NeilBrown f416885ef495050 NeilBrown 63c70c4f3a30e77 NeilBrown 63c70c4f3a30e77 NeilBrown 01ee22b496c4138 NeilBrown 01ee22b496c4138 NeilBrown 01ee22b496c4138 NeilBrown 30b67645faadcdc NeilBrown 30b67645faadcdc NeilBrown 30b67645faadcdc NeilBrown c6563a8c38fde3c NeilBrown 469518a3455c796 NeilBrown 1a940fcee31ec6c NeilBrown 292695531ae4019 NeilBrown c6563a8c38fde3c NeilBrown 63c70c4f3a30e77 NeilBrown f416885ef495050 NeilBrown 292695531ae4019 NeilBrown 292695531ae4019 NeilBrown 292695531ae4019 NeilBrown 292695531ae4019 NeilBrown 292695531ae4019 NeilBrown ec32a2bd35bd6b9 NeilBrown ec32a2bd35bd6b9 NeilBrown ec32a2bd35bd6b9 NeilBrown ec32a2bd35bd6b9 NeilBrown ec32a2bd35bd6b9 NeilBrown ec32a2bd35bd6b9 NeilBrown cc6167b4f3b3caa NeilBrown cc6167b4f3b3caa NeilBrown ec32a2bd35bd6b9 NeilBrown ec32a2bd35bd6b9 NeilBrown ec32a2bd35bd6b9 NeilBrown f67055780caac6a NeilBrown 292695531ae4019 NeilBrown c46501b2deaa06e NeilBrown 292695531ae4019 NeilBrown 63c70c4f3a30e77 NeilBrown 09c9e5fa1b93ad5 Andre Noll 09c9e5fa1b93ad5 Andre Noll 88ce4930e2b8037 NeilBrown 88ce4930e2b8037 NeilBrown 05616be5e11f668 NeilBrown 05616be5e11f668 NeilBrown 05616be5e11f668 NeilBrown 05616be5e11f668 NeilBrown 05616be5e11f668 NeilBrown 2c810cddc44d6f9 NeilBrown fef9c61fdfabf97 NeilBrown fef9c61fdfabf97 NeilBrown fef9c61fdfabf97 NeilBrown fef9c61fdfabf97 NeilBrown c46501b2deaa06e NeilBrown 292695531ae4019 NeilBrown 292695531ae4019 NeilBrown 4d77e3ba88d0858 NeilBrown 4d77e3ba88d0858 NeilBrown 4d77e3ba88d0858 NeilBrown 4d77e3ba88d0858 NeilBrown 4d77e3ba88d0858 NeilBrown 4d77e3ba88d0858 NeilBrown 4d77e3ba88d0858 NeilBrown 292695531ae4019 NeilBrown 292695531ae4019 NeilBrown 3424bf6a772cff6 NeilBrown 3424bf6a772cff6 NeilBrown 3424bf6a772cff6 NeilBrown 3424bf6a772cff6 NeilBrown 292695531ae4019 NeilBrown 87a8dec91e15954 NeilBrown dafb20fa34320a4 NeilBrown 292695531ae4019 NeilBrown 292695531ae4019 NeilBrown 199050ea1ff2270 Neil Brown 87a8dec91e15954 NeilBrown 9d4c7d8799c4188 NeilBrown 292695531ae4019 NeilBrown 9d4c7d8799c4188 NeilBrown 9eb07c259207d04 NeilBrown 36fad858a7404a9 36fad858a7404a9 00bcb4ac7ee7e55 NeilBrown 50da08409654e03 NeilBrown 1a940fcee31ec6c NeilBrown 1a940fcee31ec6c NeilBrown 1a940fcee31ec6c NeilBrown 1a940fcee31ec6c NeilBrown 292695531ae4019 NeilBrown 292695531ae4019 NeilBrown 87a8dec91e15954 NeilBrown 87a8dec91e15954 NeilBrown 87a8dec91e15954 NeilBrown 87a8dec91e15954 NeilBrown c04be0aa82ff535 NeilBrown 2e38a37f23c98d7 Song Liu c04be0aa82ff535 NeilBrown ec32a2bd35bd6b9 NeilBrown 63c70c4f3a30e77 NeilBrown e516402c0d4fc02 NeilBrown 2953079c692da06 Shaohua Li f67055780caac6a NeilBrown 292695531ae4019 NeilBrown 292695531ae4019 NeilBrown ea358cd0d2c634f NeilBrown 292695531ae4019 NeilBrown 292695531ae4019 NeilBrown 292695531ae4019 NeilBrown 0da3c6194ec2f32 NeilBrown 292695531ae4019 NeilBrown 292695531ae4019 NeilBrown 292695531ae4019 NeilBrown ba8805b97320416 NeilBrown 292695531ae4019 NeilBrown ba8805b97320416 NeilBrown ba8805b97320416 NeilBrown ba8805b97320416 NeilBrown 05616be5e11f668 NeilBrown 05616be5e11f668 NeilBrown 05616be5e11f668 NeilBrown ba8805b97320416 NeilBrown fef9c61fdfabf97 NeilBrown 1e3fa9bd5061778 NeilBrown ba8805b97320416 NeilBrown 292695531ae4019 NeilBrown 292695531ae4019 NeilBrown 292695531ae4019 NeilBrown c8f517c444e4f9f NeilBrown 292695531ae4019 NeilBrown 292695531ae4019 NeilBrown 292695531ae4019 NeilBrown 292695531ae4019 NeilBrown 292695531ae4019 NeilBrown
:::::: The code :::::: c46501b2deaa06efca
:::::: TO: NeilBrown :::::: CC: NeilBrown
---
0-DAY CI Kernel Attachment: Description: application/gzip message: Paul E. McKenney: "Re: [PATCH] kcsan: Optimize debugfs stats counters" message: Rob Herring: "Re: [PATCH] dt-bindings: Whitespace clean-ups in schema files" sorted by: [ date ] [ thread ] [ subject ] [ author ] href="https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git">https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
c6a06a66e721f4ce1dd783a
48aa6afc636808f31ecb87a seqlock: Extend seqcount API with associated locks
(attached as .config)
(Debian 9.3.0-15) 9.3.0
kindly add following tag as appropriate
test robot <lkp@xxxxxxxxx>
raid5_start_reshape() warn: statement has no effect 31
alloc_thread_groups() warn: double check that we're allocating correct size: 108 vs 1
setup_conf() warn: should 'mddev->new_chunk_sectors << 9' be a 64 bit type?
raid5_start_reshape() warn: statement has no effect 31
2006-03-27 7860
2011-10-11 7861 static int raid5_start_reshape(struct mddev *mddev)
2006-03-27 7862 {
2011-10-11 7863 struct r5conf *conf = mddev->private;
2011-10-11 7864 struct md_rdev *rdev;
2006-03-27 7865 int spares = 0;
2006-10-03 7866 unsigned long flags;
2006-03-27 7867
2007-02-28 7868 if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
2006-03-27 7869 return -EBUSY;
2006-03-27 7870
2009-06-18 7871 if (!check_stripe_cache(mddev))
2009-06-18 7872 return -ENOSPC;
2009-06-18 7873
2012-05-22 7874 if (has_failed(conf))
2012-05-22 7875 return -EINVAL;
2012-05-22 7876
2012-05-21 7877 rdev_for_each(rdev, mddev) {
2011-01-31 7878 if (!test_bit(In_sync, &rdev->flags)
2011-01-14 7879 && !test_bit(Faulty, &rdev->flags))
2006-03-27 7880 spares++;
2012-05-21 7881 }
2006-03-27 7882
2007-02-28 7883 if (spares - mddev->degraded < mddev->delta_disks - conf->max_degraded)
2006-03-27 7884 /* Not enough devices even to make a degraded array
2006-03-27 7885 * of that size
2006-03-27 7886 */
2006-03-27 7887 return -EINVAL;
2006-03-27 7888
2009-03-31 7889 /* Refuse to reduce size of the array. Any reductions in
2009-03-31 7890 * array size must be through explicit setting of array_size
2009-03-31 7891 * attribute.
2009-03-31 7892 */
2009-03-31 7893 if (raid5_size(mddev, 0, conf->raid_disks + mddev->delta_disks)
2009-03-31 7894 < mddev->array_sectors) {
2016-11-02 7895 pr_warn("md/raid:%s: array size must be reduced before number of disks\n",
2016-11-02 7896 mdname(mddev));
2009-03-31 7897 return -EINVAL;
2009-03-31 7898 }
2009-03-31 7899
2006-03-27 7900 atomic_set(&conf->reshape_stripes, 0);
2006-03-27 7901 spin_lock_irq(&conf->device_lock);
2013-08-27 @7902 write_seqcount_begin(&conf->gen_lock);
2006-03-27 7903 conf->previous_raid_disks = conf->raid_disks;
2006-03-27 7904 conf->raid_disks += mddev->delta_disks;
2009-06-18 7905 conf->prev_chunk_sectors = conf->chunk_sectors;
2009-06-18 7906 conf->chunk_sectors = mddev->new_chunk_sectors;
2009-03-31 7907 conf->prev_algo = conf->algorithm;
2009-03-31 7908 conf->algorithm = mddev->new_layout;
2012-05-21 7909 conf->generation++;
2012-05-21 7910 /* Code that selects data_offset needs to see the generation update
2012-05-21 7911 * if reshape_progress has been set - so a memory barrier needed.
2012-05-21 7912 */
2012-05-21 7913 smp_mb();
2012-05-21 7914 if (mddev->reshape_backwards)
2009-03-31 7915 conf->reshape_progress = raid5_size(mddev, 0, 0);
2009-03-31 7916 else
2009-03-31 7917 conf->reshape_progress = 0;
2009-03-31 7918 conf->reshape_safe = conf->reshape_progress;
2013-08-27 7919 write_seqcount_end(&conf->gen_lock);
2006-03-27 7920 spin_unlock_irq(&conf->device_lock);
2006-03-27 7921
2013-08-27 7922 /* Now make sure any requests that proceeded on the assumption
2013-08-27 7923 * the reshape wasn't running - like Discard or Read - have
2013-08-27 7924 * completed.
2013-08-27 7925 */
2013-08-27 7926 mddev_suspend(mddev);
2013-08-27 7927 mddev_resume(mddev);
2013-08-27 7928
2006-03-27 7929 /* Add some new drives, as many as will fit.
2006-03-27 7930 * We know there are enough to make the newly sized array work.
2010-06-17 7931 * Don't add devices if we are reducing the number of
2010-06-17 7932 * devices in the array. This is because it is not possible
2010-06-17 7933 * to correctly record the "partially reconstructed" state of
2010-06-17 7934 * such devices during the reshape and confusion could result.
2006-03-27 7935 */
2011-01-31 7936 if (mddev->delta_disks >= 0) {
2012-03-19 7937 rdev_for_each(rdev, mddev)
2006-03-27 7938 if (rdev->raid_disk < 0 &&
2006-03-27 7939 !test_bit(Faulty, &rdev->flags)) {
2008-06-28 7940 if (raid5_add_disk(mddev, rdev) == 0) {
2011-01-31 7941 if (rdev->raid_disk
2012-03-13 7942 >= conf->previous_raid_disks)
2006-03-27 7943 set_bit(In_sync, &rdev->flags);
2012-03-13 7944 else
2010-02-09 7945 rdev->recovery_offset = 0;
Namhyung Kim 2011-07-27 7946
Namhyung Kim 2011-07-27 7947 if (sysfs_link_rdev(mddev, rdev))
2010-06-01 7948 /* Failure here is OK */;
2011-01-31 7949 }
2011-01-14 7950 } else if (rdev->raid_disk >= conf->previous_raid_disks
2011-01-14 7951 && !test_bit(Faulty, &rdev->flags)) {
2011-01-14 7952 /* This is a spare that was manually added */
2011-01-14 7953 set_bit(In_sync, &rdev->flags);
2006-03-27 7954 }
2006-03-27 7955
2011-01-31 7956 /* When a reshape changes the number of devices,
2011-01-31 7957 * ->degraded is measured against the larger of the
2011-01-31 7958 * pre and post number of devices.
2011-01-31 7959 */
2006-10-03 7960 spin_lock_irqsave(&conf->device_lock, flags);
2017-01-24 7961 mddev->degraded = raid5_calc_degraded(conf);
2006-10-03 7962 spin_unlock_irqrestore(&conf->device_lock, flags);
2009-03-31 7963 }
2006-03-27 7964 mddev->raid_disks = conf->raid_disks;
2009-08-03 7965 mddev->reshape_position = conf->reshape_progress;
2016-12-08 7966 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
2006-03-27 7967
2006-03-27 7968 clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
2006-03-27 7969 clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
2015-06-12 7970 clear_bit(MD_RECOVERY_DONE, &mddev->recovery);
2006-03-27 7971 set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
2006-03-27 7972 set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
2006-03-27 7973 mddev->sync_thread = md_register_thread(md_do_sync, mddev,
2009-09-23 7974 "reshape");
2006-03-27 7975 if (!mddev->sync_thread) {
2006-03-27 7976 mddev->recovery = 0;
2006-03-27 7977 spin_lock_irq(&conf->device_lock);
2013-11-14 7978 write_seqcount_begin(&conf->gen_lock);
2006-03-27 7979 mddev->raid_disks = conf->raid_disks = conf->previous_raid_disks;
2013-11-14 7980 mddev->new_chunk_sectors =
2013-11-14 7981 conf->chunk_sectors = conf->prev_chunk_sectors;
2013-11-14 7982 mddev->new_layout = conf->algorithm = conf->prev_algo;
2012-05-21 7983 rdev_for_each(rdev, mddev)
2012-05-21 7984 rdev->new_data_offset = rdev->data_offset;
2012-05-21 7985 smp_wmb();
2013-11-14 7986 conf->generation --;
2009-03-31 7987 conf->reshape_progress = MaxSector;
2012-03-13 7988 mddev->reshape_position = MaxSector;
2013-11-14 7989 write_seqcount_end(&conf->gen_lock);
2006-03-27 7990 spin_unlock_irq(&conf->device_lock);
2006-03-27 7991 return -EAGAIN;
2006-03-27 7992 }
2009-03-31 7993 conf->reshape_checkpoint = jiffies;
2006-03-27 7994 md_wakeup_thread(mddev->sync_thread);
2006-03-27 7995 md_new_event(mddev);
2006-03-27 7996 return 0;
2006-03-27 7997 }
2006-03-27 7998
at line 7902 was first introduced by commit
af82917281941f02c6b307 md/raid5: use seqcount to protect access to shape in make_request.
<neilb@xxxxxxx>
<neilb@xxxxxxx>
Test Service, Intel Corporation
href="https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx">https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx
>.config.gz

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