[dm-devel] [PATCH 5/6] dm: use non-reentrant workqueues if equivalent

[Tejun Heo]

kmirrord_wq, kcopyd_work and md->wq are created per dm instance and
serves only single work item from the dm instance, so non-reentrant
workqueues would provide the same ordering guarantees as ordered ones
while allowing CPU affinity and use of the workqueues for other
purposes.  Switch them to non-reentrant workqueues.

Signed-off-by: Tejun Heo <tj at kernel.org>
Cc: Mike Snitzer <snitzer at redhat.com>
Cc: dm-devel at redhat.com
---
 drivers/md/dm-kcopyd.c |    3 ++-
 drivers/md/dm-raid1.c  |    3 ++-
 drivers/md/dm.c        |    3 ++-
 3 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/md/dm-kcopyd.c b/drivers/md/dm-kcopyd.c
index 6d641e8..20c1a11 100644
--- a/drivers/md/dm-kcopyd.c
+++ b/drivers/md/dm-kcopyd.c
@@ -624,7 +624,8 @@ int dm_kcopyd_client_create(unsigned int nr_pages,
 		goto bad_slab;
 
 	INIT_WORK(&kc->kcopyd_work, do_work);
-	kc->kcopyd_wq = alloc_ordered_workqueue("kcopyd", WQ_MEM_RECLAIM);
+	kc->kcopyd_wq = alloc_workqueue("kcopyd",
+					WQ_NON_REENTRANT | WQ_MEM_RECLAIM, 0);
 	if (!kc->kcopyd_wq)
 		goto bad_workqueue;
 
diff --git a/drivers/md/dm-raid1.c b/drivers/md/dm-raid1.c
index 5139091..32bc404 100644
--- a/drivers/md/dm-raid1.c
+++ b/drivers/md/dm-raid1.c
@@ -1077,7 +1077,8 @@ static int mirror_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 	ti->split_io = dm_rh_get_region_size(ms->rh);
 	ti->num_flush_requests = 1;
 
-	ms->kmirrord_wq = alloc_ordered_workqueue("kmirrord", WQ_MEM_RECLAIM);
+	ms->kmirrord_wq = alloc_workqueue("kmirrord",
+					  WQ_NON_REENTRANT | WQ_MEM_RECLAIM, 0);
 	if (!ms->kmirrord_wq) {
 		DMERR("couldn't start kmirrord");
 		r = -ENOMEM;
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 064b2dc..854409d 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1884,7 +1884,8 @@ static struct mapped_device *alloc_dev(int minor)
 	add_disk(md->disk);
 	format_dev_t(md->name, MKDEV(_major, minor));
 
-	md->wq = alloc_ordered_workqueue("kdmflush", WQ_MEM_RECLAIM);
+	md->wq = alloc_workqueue("kdmflush",
+				 WQ_NON_REENTRANT | WQ_MEM_RECLAIM, 0);
 	if (!md->wq)
 		goto bad_thread;
 
-- 
1.7.1