diff options
| author | Yu Kuai <yukuai3@huawei.com> | 2023-11-25 11:16:00 +0300 |
|---|---|---|
| committer | Song Liu <song@kernel.org> | 2023-11-28 02:49:04 +0300 |
| commit | c891f1fd90e66e584bb1353e1859cef7c9eb36f8 (patch) | |
| tree | 564d8541ff7bc4be1145f85bb0ef194c833ea587 /drivers/md/md.h | |
| parent | bed9e27baf52a09b7ba2a3714f1e24e17ced386d (diff) | |
| download | linux-c891f1fd90e66e584bb1353e1859cef7c9eb36f8.tar.xz | |
md: remove flag RemoveSynchronized
rcu is not used correctly here, because synchronize_rcu() is called
before replacing old value, for example:
remove_and_add_spares // other path
synchronize_rcu
// called before replacing old value
set_bit(RemoveSynchronized)
rcu_read_lock()
rdev = conf->mirros[].rdev
pers->hot_remove_disk
conf->mirros[].rdev = NULL;
if (!test_bit(RemoveSynchronized))
synchronize_rcu
/*
* won't be called, and won't wait
* for concurrent readers to be done.
*/
// access rdev after remove_and_add_spares()
rcu_read_unlock()
Fortunately, there is a separate rcu protection to prevent such rdev
to be freed:
md_kick_rdev_from_array //other path
rcu_read_lock()
rdev = conf->mirros[].rdev
list_del_rcu(&rdev->same_set)
rcu_read_unlock()
/*
* rdev can be removed from conf, but
* rdev won't be freed.
*/
synchronize_rcu()
free rdev
Hence remove this useless flag and prepare to remove rcu protection to
access rdev from 'conf'.
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20231125081604.3939938-2-yukuai1@huaweicloud.com
Diffstat (limited to 'drivers/md/md.h')
| -rw-r--r-- | drivers/md/md.h | 5 |
1 files changed, 0 insertions, 5 deletions
diff --git a/drivers/md/md.h b/drivers/md/md.h index ade83af123a2..8d881cc59799 100644 --- a/drivers/md/md.h +++ b/drivers/md/md.h @@ -190,11 +190,6 @@ enum flag_bits { * than other devices in the array */ ClusterRemove, - RemoveSynchronized, /* synchronize_rcu() was called after - * this device was known to be faulty, - * so it is safe to remove without - * another synchronize_rcu() call. - */ ExternalBbl, /* External metadata provides bad * block management for a disk */ |