NFSD: refactoring courtesy_client_reaper to a generic low memory shrinker

Refactoring courtesy_client_reaper to generic low memory
shrinker so it can be used for other purposes.
Signed-off-by: NDai Ngo <dai.ngo@oracle.com>
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>

fs/nfsd/nfs4state.c

@@ -4361,7 +4361,7 @@ nfsd4_init_slabs(void)
 }
 
 static unsigned long
-nfsd_courtesy_client_count(struct shrinker *shrink, struct shrink_control *sc)
+nfsd4_state_shrinker_count(struct shrinker *shrink, struct shrink_control *sc)
 {
 	int cnt;
 	struct nfsd_net *nn = container_of(shrink,
@@ -4374,7 +4374,7 @@ nfsd_courtesy_client_count(struct shrinker *shrink, struct shrink_control *sc)
 }
 
 static unsigned long
-nfsd_courtesy_client_scan(struct shrinker *shrink, struct shrink_control *sc)
+nfsd4_state_shrinker_scan(struct shrinker *shrink, struct shrink_control *sc)
 {
 	return SHRINK_STOP;
 }
@@ -4401,8 +4401,8 @@ nfsd4_init_leases_net(struct nfsd_net *nn)
 	nn->nfs4_max_clients = max_t(int, max_clients, NFS4_CLIENTS_PER_GB);
 
 	atomic_set(&nn->nfsd_courtesy_clients, 0);
-	nn->nfsd_client_shrinker.scan_objects = nfsd_courtesy_client_scan;
-	nn->nfsd_client_shrinker.count_objects = nfsd_courtesy_client_count;
+	nn->nfsd_client_shrinker.scan_objects = nfsd4_state_shrinker_scan;
+	nn->nfsd_client_shrinker.count_objects = nfsd4_state_shrinker_count;
 	nn->nfsd_client_shrinker.seeks = DEFAULT_SEEKS;
 	return register_shrinker(&nn->nfsd_client_shrinker, "nfsd-client");
 }
@@ -6151,17 +6151,24 @@ laundromat_main(struct work_struct *laundry)
 }
 
 static void
-courtesy_client_reaper(struct work_struct *reaper)
+courtesy_client_reaper(struct nfsd_net *nn)
 {
 	struct list_head reaplist;
-	struct delayed_work *dwork = to_delayed_work(reaper);
-	struct nfsd_net *nn = container_of(dwork, struct nfsd_net,
-					nfsd_shrinker_work);
 
 	nfs4_get_courtesy_client_reaplist(nn, &reaplist);
 	nfs4_process_client_reaplist(&reaplist);
 }
 
+static void
+nfsd4_state_shrinker_worker(struct work_struct *work)
+{
+	struct delayed_work *dwork = to_delayed_work(work);
+	struct nfsd_net *nn = container_of(dwork, struct nfsd_net,
+				nfsd_shrinker_work);
+
+	courtesy_client_reaper(nn);
+}
+
 static inline __be32 nfs4_check_fh(struct svc_fh *fhp, struct nfs4_stid *stp)
 {
 	if (!fh_match(&fhp->fh_handle, &stp->sc_file->fi_fhandle))
@@ -7985,7 +7992,7 @@ static int nfs4_state_create_net(struct net *net)
 	INIT_LIST_HEAD(&nn->blocked_locks_lru);
 
 	INIT_DELAYED_WORK(&nn->laundromat_work, laundromat_main);
-	INIT_DELAYED_WORK(&nn->nfsd_shrinker_work, courtesy_client_reaper);
+	INIT_DELAYED_WORK(&nn->nfsd_shrinker_work, nfsd4_state_shrinker_worker);
 	get_net(net);
 
 	return 0;