[PATCH v2 13/18] raid5: Use sequence counter with associated spinlock
STALE2214d
From: Ahmed S. Darwish <hidden>
Date: 2020-06-08 00:59:30
Also in:
lkml
Subsystem:
software raid (multiple disks) support, the rest · Maintainers:
Song Liu, Yu Kuai, Linus Torvalds
Revision v2 of 4 in this series.
Revisions (4)
- v1 [diff vs current]
- v2 current
- v3 [diff vs current]
- v4 [diff vs current]
A sequence counter write side critical section must be protected by some form of locking to serialize writers. A plain seqcount_t does not contain the information of which lock must be held when entering a write side critical section. Use the new seqcount_spinlock_t data type, which allows to associate a spinlock with the sequence counter. This enables lockdep to verify that the spinlock used for writer serialization is held when the write side critical section is entered. If lockdep is disabled this lock association is compiled out and has neither storage size nor runtime overhead. Signed-off-by: Ahmed S. Darwish <redacted> --- drivers/md/raid5.c | 2 +- drivers/md/raid5.h | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index ba00e9877f02..69f31c675b58 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c@@ -6929,7 +6929,7 @@ static struct r5conf *setup_conf(struct mddev *mddev) } else goto abort; spin_lock_init(&conf->device_lock); - seqcount_init(&conf->gen_lock); + seqcount_spinlock_init(&conf->gen_lock, &conf->device_lock); mutex_init(&conf->cache_size_mutex); init_waitqueue_head(&conf->wait_for_quiescent); init_waitqueue_head(&conf->wait_for_stripe);
diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h
index f90e0704bed9..a2c9e9e9f5ac 100644
--- a/drivers/md/raid5.h
+++ b/drivers/md/raid5.h@@ -589,7 +589,7 @@ struct r5conf { int prev_chunk_sectors; int prev_algo; short generation; /* increments with every reshape */ - seqcount_t gen_lock; /* lock against generation changes */ + seqcount_spinlock_t gen_lock; /* lock against generation changes */ unsigned long reshape_checkpoint; /* Time we last updated * metadata */ long long min_offset_diff; /* minimum difference between
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2.20.1