dm: use non reentrant workqueues if equivalent

kmirrord_wq, kcopyd_work and md->wq are created per dm instance and
serve only a 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@kernel.org>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

3 files changed, 7 insertions, 4 deletions

diff --git a/drivers/md/dm-kcopyd.c b/drivers/md/dm-kcopyd.c
index 63d67169c7f4..924f5f0084c2 100644
--- a/drivers/md/dm-kcopyd.c
+++ b/drivers/md/dm-kcopyd.c
@@ -672,7 +672,8 @@ 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 39917430f9f8..dee326775c60 100644
--- a/drivers/md/dm-raid1.c
+++ b/drivers/md/dm-raid1.c
@@ -1085,7 +1085,8 @@ static int mirror_ctr(struct dm_target *ti, unsigned int argc, char **argv)
         ti->num_flush_requests = 1;
         ti->num_discard_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;
@@ -1414,7 +1415,7 @@ static int mirror_iterate_devices(struct dm_target *ti,
 
 static struct target_type mirror_target = {
         .name    = "mirror",
-        .version = {1, 12, 0},
+        .version = {1, 12, 1},
         .module  = THIS_MODULE,
         .ctr     = mirror_ctr,
         .dtr     = mirror_dtr,
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 39aaa9290128..e504bb40d60e 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1883,7 +1883,8 @@ 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;