fs/afs/flock: Remove deprecated create_singlethread_workqueue

The workqueue "afs_lock_manager" queues work item &vnode->lock_work,
per vnode. Since there can be multiple vnodes and since their work items
can be executed concurrently, alloc_workqueue has been used to replace
the deprecated create_singlethread_workqueue instance.

The WQ_MEM_RECLAIM flag has been set to ensure forward progress under
memory pressure because the workqueue is being used on a memory reclaim
path.

Since there are fixed number of work items, explicit concurrency
limit is unnecessary here.

Signed-off-by: Bhaktipriya Shridhar <bhaktipriya96@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>

fs/afs/flock.c

@@ -36,8 +36,8 @@ static int afs_init_lock_manager(void)
 	if (!afs_lock_manager) {
 		mutex_lock(&afs_lock_manager_mutex);
 		if (!afs_lock_manager) {
-			afs_lock_manager =
-				create_singlethread_workqueue("kafs_lockd");
+			afs_lock_manager = alloc_workqueue("kafs_lockd",
+							   WQ_MEM_RECLAIM, 0);
 			if (!afs_lock_manager)
 				ret = -ENOMEM;
 		}