diff options
| author | Will Deacon <will.deacon@arm.com> | 2017-10-24 11:22:48 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2017-10-24 13:17:33 +0200 |
| commit | 506458efaf153c1ea480591c5602a5a3ba5a3b76 (patch) | |
| tree | c4ac0a89bf23993036720ec8883fff0740bf9019 /drivers/md | |
| parent | 76ebbe78f7390aee075a7f3768af197ded1bdfbb (diff) | |
locking/barriers: Convert users of lockless_dereference() to READ_ONCE()
READ_ONCE() now has an implicit smp_read_barrier_depends() call, so it
can be used instead of lockless_dereference() without any change in
semantics.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1508840570-22169-4-git-send-email-will.deacon@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'drivers/md')
| -rw-r--r-- | drivers/md/dm-mpath.c | 20 |
1 files changed, 10 insertions, 10 deletions
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c index 11f273d2f018..3f88c9d32f7e 100644 --- a/drivers/md/dm-mpath.c +++ b/drivers/md/dm-mpath.c @@ -366,7 +366,7 @@ static struct pgpath *choose_path_in_pg(struct multipath *m, pgpath = path_to_pgpath(path); - if (unlikely(lockless_dereference(m->current_pg) != pg)) { + if (unlikely(READ_ONCE(m->current_pg) != pg)) { /* Only update current_pgpath if pg changed */ spin_lock_irqsave(&m->lock, flags); m->current_pgpath = pgpath; @@ -390,7 +390,7 @@ static struct pgpath *choose_pgpath(struct multipath *m, size_t nr_bytes) } /* Were we instructed to switch PG? */ - if (lockless_dereference(m->next_pg)) { + if (READ_ONCE(m->next_pg)) { spin_lock_irqsave(&m->lock, flags); pg = m->next_pg; if (!pg) { @@ -406,7 +406,7 @@ static struct pgpath *choose_pgpath(struct multipath *m, size_t nr_bytes) /* Don't change PG until it has no remaining paths */ check_current_pg: - pg = lockless_dereference(m->current_pg); + pg = READ_ONCE(m->current_pg); if (pg) { pgpath = choose_path_in_pg(m, pg, nr_bytes); if (!IS_ERR_OR_NULL(pgpath)) @@ -473,7 +473,7 @@ static int multipath_clone_and_map(struct dm_target *ti, struct request *rq, struct request *clone; /* Do we need to select a new pgpath? */ - pgpath = lockless_dereference(m->current_pgpath); + pgpath = READ_ONCE(m->current_pgpath); if (!pgpath || !test_bit(MPATHF_QUEUE_IO, &m->flags)) pgpath = choose_pgpath(m, nr_bytes); @@ -535,7 +535,7 @@ static int __multipath_map_bio(struct multipath *m, struct bio *bio, struct dm_m bool queue_io; /* Do we need to select a new pgpath? */ - pgpath = lockless_dereference(m->current_pgpath); + pgpath = READ_ONCE(m->current_pgpath); queue_io = test_bit(MPATHF_QUEUE_IO, &m->flags); if (!pgpath || !queue_io) pgpath = choose_pgpath(m, nr_bytes); @@ -1804,7 +1804,7 @@ static int multipath_prepare_ioctl(struct dm_target *ti, struct pgpath *current_pgpath; int r; - current_pgpath = lockless_dereference(m->current_pgpath); + current_pgpath = READ_ONCE(m->current_pgpath); if (!current_pgpath) current_pgpath = choose_pgpath(m, 0); @@ -1826,7 +1826,7 @@ static int multipath_prepare_ioctl(struct dm_target *ti, } if (r == -ENOTCONN) { - if (!lockless_dereference(m->current_pg)) { + if (!READ_ONCE(m->current_pg)) { /* Path status changed, redo selection */ (void) choose_pgpath(m, 0); } @@ -1895,9 +1895,9 @@ static int multipath_busy(struct dm_target *ti) return (m->queue_mode != DM_TYPE_MQ_REQUEST_BASED); /* Guess which priority_group will be used at next mapping time */ - pg = lockless_dereference(m->current_pg); - next_pg = lockless_dereference(m->next_pg); - if (unlikely(!lockless_dereference(m->current_pgpath) && next_pg)) + pg = READ_ONCE(m->current_pg); + next_pg = READ_ONCE(m->next_pg); + if (unlikely(!READ_ONCE(m->current_pgpath) && next_pg)) pg = next_pg; if (!pg) { |