workqueue: deprecate system_nrt[_freezable]_wq

system_nrt[_freezable]_wq are now spurious.  Mark them deprecated and
convert all users to system[_freezable]_wq.

If you're cc'd and wondering what's going on: Now all workqueues are
non-reentrant, so there's no reason to use system_nrt[_freezable]_wq.
Please use system[_freezable]_wq instead.

This patch doesn't make any functional difference.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-By: Lai Jiangshan <laijs@cn.fujitsu.com>

Cc: Jens Axboe <axboe@kernel.dk>
Cc: David Airlie <airlied@linux.ie>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: David Howells <dhowells@redhat.com>
diff --git a/block/genhd.c b/block/genhd.c
index 5d8b44a..a2f3d6a 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -1490,9 +1490,9 @@
 	intv = disk_events_poll_jiffies(disk);
 	set_timer_slack(&ev->dwork.timer, intv / 4);
 	if (check_now)
-		queue_delayed_work(system_nrt_freezable_wq, &ev->dwork, 0);
+		queue_delayed_work(system_freezable_wq, &ev->dwork, 0);
 	else if (intv)
-		queue_delayed_work(system_nrt_freezable_wq, &ev->dwork, intv);
+		queue_delayed_work(system_freezable_wq, &ev->dwork, intv);
 out_unlock:
 	spin_unlock_irqrestore(&ev->lock, flags);
 }
@@ -1535,7 +1535,7 @@
 	spin_lock_irq(&ev->lock);
 	ev->clearing |= mask;
 	if (!ev->block)
-		mod_delayed_work(system_nrt_freezable_wq, &ev->dwork, 0);
+		mod_delayed_work(system_freezable_wq, &ev->dwork, 0);
 	spin_unlock_irq(&ev->lock);
 }
 
@@ -1571,7 +1571,7 @@
 
 	/* uncondtionally schedule event check and wait for it to finish */
 	disk_block_events(disk);
-	queue_delayed_work(system_nrt_freezable_wq, &ev->dwork, 0);
+	queue_delayed_work(system_freezable_wq, &ev->dwork, 0);
 	flush_delayed_work(&ev->dwork);
 	__disk_unblock_events(disk, false);
 
@@ -1608,7 +1608,7 @@
 
 	intv = disk_events_poll_jiffies(disk);
 	if (!ev->block && intv)
-		queue_delayed_work(system_nrt_freezable_wq, &ev->dwork, intv);
+		queue_delayed_work(system_freezable_wq, &ev->dwork, intv);
 
 	spin_unlock_irq(&ev->lock);