[PATCH] ocfs2: use hlists for lockres hash

Switch from list_head to hlist_head. Make the size of the hash dependent
upon the allocated area, rather than a constant.
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>

fs/ocfs2/dlm/dlmcommon.h

@@ -37,9 +37,7 @@
 #define DLM_THREAD_SHUFFLE_INTERVAL    5     // flush everything every 5 passes
 #define DLM_THREAD_MS                  200   // flush at least every 200 ms
 
-#define DLM_HASH_BITS     7
-#define DLM_HASH_SIZE     (1 << DLM_HASH_BITS)
-#define DLM_HASH_MASK     (DLM_HASH_SIZE - 1)
+#define DLM_HASH_BUCKETS     (PAGE_SIZE / sizeof(struct hlist_head))
 
 enum dlm_ast_type {
 	DLM_AST = 0,
@@ -87,7 +85,7 @@ enum dlm_ctxt_state {
 struct dlm_ctxt
 {
 	struct list_head list;
-	struct list_head *resources;
+	struct hlist_head *lockres_hash;
 	struct list_head dirty_list;
 	struct list_head purge_list;
 	struct list_head pending_asts;
@@ -217,7 +215,7 @@ struct dlm_lock_resource
 {
 	/* WARNING: Please see the comment in dlm_init_lockres before
 	 * adding fields here. */
-	struct list_head list;
+	struct hlist_node hash_node;
 	struct kref      refs;
 
 	/* please keep these next 3 in this order

fs/ocfs2/dlm/dlmdebug.c

@@ -117,8 +117,8 @@ EXPORT_SYMBOL_GPL(dlm_print_one_lock);
 void dlm_dump_lock_resources(struct dlm_ctxt *dlm)
 {
 	struct dlm_lock_resource *res;
-	struct list_head *iter;
-	struct list_head *bucket;
+	struct hlist_node *iter;
+	struct hlist_head *bucket;
 	int i;
 
 	mlog(ML_NOTICE, "struct dlm_ctxt: %s, node=%u, key=%u\n",
@@ -129,12 +129,10 @@ void dlm_dump_lock_resources(struct dlm_ctxt *dlm)
 	}
 
 	spin_lock(&dlm->spinlock);
-	for (i=0; i<DLM_HASH_SIZE; i++) {
-		bucket = &(dlm->resources[i]);
-		list_for_each(iter, bucket) {
-			res = list_entry(iter, struct dlm_lock_resource, list);
+	for (i=0; i<DLM_HASH_BUCKETS; i++) {
+		bucket = &(dlm->lockres_hash[i]);
+		hlist_for_each_entry(res, iter, bucket, hash_node)
 			dlm_print_one_lock_resource(res);
-		}
 	}
 	spin_unlock(&dlm->spinlock);
 }

fs/ocfs2/dlm/dlmdomain.c

@@ -77,26 +77,26 @@ static void dlm_unregister_domain_handlers(struct dlm_ctxt *dlm);
 
 void __dlm_unhash_lockres(struct dlm_lock_resource *lockres)
 {
-	list_del_init(&lockres->list);
+	hlist_del_init(&lockres->hash_node);
 	dlm_lockres_put(lockres);
 }
 
 void __dlm_insert_lockres(struct dlm_ctxt *dlm,
 		       struct dlm_lock_resource *res)
 {
-	struct list_head *bucket;
+	struct hlist_head *bucket;
 	struct qstr *q;
 
 	assert_spin_locked(&dlm->spinlock);
 
 	q = &res->lockname;
 	q->hash = full_name_hash(q->name, q->len);
-	bucket = &(dlm->resources[q->hash & DLM_HASH_MASK]);
+	bucket = &(dlm->lockres_hash[q->hash % DLM_HASH_BUCKETS]);
 
 	/* get a reference for our hashtable */
 	dlm_lockres_get(res);
 
-	list_add_tail(&res->list, bucket);
+	hlist_add_head(&res->hash_node, bucket);
 }
 
 struct dlm_lock_resource * __dlm_lookup_lockres(struct dlm_ctxt *dlm,
@@ -104,9 +104,9 @@ struct dlm_lock_resource * __dlm_lookup_lockres(struct dlm_ctxt *dlm,
 					 unsigned int len)
 {
 	unsigned int hash;
-	struct list_head *iter;
+	struct hlist_node *iter;
 	struct dlm_lock_resource *tmpres=NULL;
-	struct list_head *bucket;
+	struct hlist_head *bucket;
 
 	mlog_entry("%.*s\n", len, name);
 
@@ -114,11 +114,11 @@ struct dlm_lock_resource * __dlm_lookup_lockres(struct dlm_ctxt *dlm,
 
 	hash = full_name_hash(name, len);
 
-	bucket = &(dlm->resources[hash & DLM_HASH_MASK]);
+	bucket = &(dlm->lockres_hash[hash % DLM_HASH_BUCKETS]);
 
 	/* check for pre-existing lock */
-	list_for_each(iter, bucket) {
-		tmpres = list_entry(iter, struct dlm_lock_resource, list);
+	hlist_for_each(iter, bucket) {
+		tmpres = hlist_entry(iter, struct dlm_lock_resource, hash_node);
 		if (tmpres->lockname.len == len &&
 		    memcmp(tmpres->lockname.name, name, len) == 0) {
 			dlm_lockres_get(tmpres);
@@ -193,8 +193,8 @@ static int dlm_wait_on_domain_helper(const char *domain)
 
 static void dlm_free_ctxt_mem(struct dlm_ctxt *dlm)
 {
-	if (dlm->resources)
-		free_page((unsigned long) dlm->resources);
+	if (dlm->lockres_hash)
+		free_page((unsigned long) dlm->lockres_hash);
 
 	if (dlm->name)
 		kfree(dlm->name);
@@ -303,10 +303,10 @@ static void dlm_migrate_all_locks(struct dlm_ctxt *dlm)
 	mlog(0, "Migrating locks from domain %s\n", dlm->name);
 restart:
 	spin_lock(&dlm->spinlock);
-	for (i=0; i<DLM_HASH_SIZE; i++) {
-		while (!list_empty(&dlm->resources[i])) {
-			res = list_entry(dlm->resources[i].next,
-				     struct dlm_lock_resource, list);
+	for (i = 0; i < DLM_HASH_BUCKETS; i++) {
+		while (!hlist_empty(&dlm->lockres_hash[i])) {
+			res = hlist_entry(dlm->lockres_hash[i].first,
+					  struct dlm_lock_resource, hash_node);
 			/* need reference when manually grabbing lockres */
 			dlm_lockres_get(res);
 			/* this should unhash the lockres
@@ -1191,18 +1191,17 @@ static struct dlm_ctxt *dlm_alloc_ctxt(const char *domain,
 		goto leave;
 	}
 
-	dlm->resources = (struct list_head *) __get_free_page(GFP_KERNEL);
-	if (!dlm->resources) {
+	dlm->lockres_hash = (struct hlist_head *) __get_free_page(GFP_KERNEL);
+	if (!dlm->lockres_hash) {
 		mlog_errno(-ENOMEM);
 		kfree(dlm->name);
 		kfree(dlm);
 		dlm = NULL;
 		goto leave;
 	}
-	memset(dlm->resources, 0, PAGE_SIZE);
 
-	for (i=0; i<DLM_HASH_SIZE; i++)
-		INIT_LIST_HEAD(&dlm->resources[i]);
+	for (i=0; i<DLM_HASH_BUCKETS; i++)
+		INIT_HLIST_HEAD(&dlm->lockres_hash[i]);
 
 	strcpy(dlm->name, domain);
 	dlm->key = key;

fs/ocfs2/dlm/dlmmaster.c

@@ -564,7 +564,7 @@ static void dlm_lockres_release(struct kref *kref)
 
 	/* By the time we're ready to blow this guy away, we shouldn't
 	 * be on any lists. */
-	BUG_ON(!list_empty(&res->list));
+	BUG_ON(!hlist_unhashed(&res->hash_node));
 	BUG_ON(!list_empty(&res->granted));
 	BUG_ON(!list_empty(&res->converting));
 	BUG_ON(!list_empty(&res->blocked));
@@ -605,7 +605,7 @@ static void dlm_init_lockres(struct dlm_ctxt *dlm,
 
 	init_waitqueue_head(&res->wq);
 	spin_lock_init(&res->spinlock);
-	INIT_LIST_HEAD(&res->list);
+	INIT_HLIST_NODE(&res->hash_node);
 	INIT_LIST_HEAD(&res->granted);
 	INIT_LIST_HEAD(&res->converting);
 	INIT_LIST_HEAD(&res->blocked);

fs/ocfs2/dlm/dlmrecovery.c

@@ -1693,7 +1693,10 @@ static void dlm_finish_local_lockres_recovery(struct dlm_ctxt *dlm,
 					      u8 dead_node, u8 new_master)
 {
 	int i;
-	struct list_head *iter, *iter2, *bucket;
+	struct list_head *iter, *iter2;
+	struct hlist_node *hash_iter;
+	struct hlist_head *bucket;
+
 	struct dlm_lock_resource *res;
 
 	mlog_entry_void();
@@ -1717,10 +1720,9 @@ static void dlm_finish_local_lockres_recovery(struct dlm_ctxt *dlm,
 	 * for now we need to run the whole hash, clear
 	 * the RECOVERING state and set the owner
 	 * if necessary */
-	for (i=0; i<DLM_HASH_SIZE; i++) {
-		bucket = &(dlm->resources[i]);
-		list_for_each(iter, bucket) {
-			res = list_entry (iter, struct dlm_lock_resource, list);
+	for (i = 0; i < DLM_HASH_BUCKETS; i++) {
+		bucket = &(dlm->lockres_hash[i]);
+		hlist_for_each_entry(res, hash_iter, bucket, hash_node) {
 			if (res->state & DLM_LOCK_RES_RECOVERING) {
 				if (res->owner == dead_node) {
 					mlog(0, "(this=%u) res %.*s owner=%u "
@@ -1852,10 +1854,10 @@ static void dlm_free_dead_locks(struct dlm_ctxt *dlm,
 
 static void dlm_do_local_recovery_cleanup(struct dlm_ctxt *dlm, u8 dead_node)
 {
-	struct list_head *iter;
+	struct hlist_node *iter;
 	struct dlm_lock_resource *res;
 	int i;
-	struct list_head *bucket;
+	struct hlist_head *bucket;
 	struct dlm_lock *lock;
 
 
@@ -1876,10 +1878,9 @@ static void dlm_do_local_recovery_cleanup(struct dlm_ctxt *dlm, u8 dead_node)
 	 *    can be kicked again to see if any ASTs or BASTs
 	 *    need to be fired as a result.
 	 */
-	for (i=0; i<DLM_HASH_SIZE; i++) {
-		bucket = &(dlm->resources[i]);
-		list_for_each(iter, bucket) {
-			res = list_entry (iter, struct dlm_lock_resource, list);
+	for (i = 0; i < DLM_HASH_BUCKETS; i++) {
+		bucket = &(dlm->lockres_hash[i]);
+		hlist_for_each_entry(res, iter, bucket, hash_node) {
  			/* always prune any $RECOVERY entries for dead nodes,
  			 * otherwise hangs can occur during later recovery */
 			if (dlm_is_recovery_lock(res->lockname.name,