dlm: keep lkbs in idr

This is simpler and quicker than the hash table, and
avoids needing to search the hash list for every new
lkid to check if it's used.

Signed-off-by: David Teigland <teigland@redhat.com>

1 files changed, 24 insertions, 45 deletions

diff --git a/fs/dlm/lock.c b/fs/dlm/lock.c
index 3c723489079a..784cde417ced 100644
--- a/fs/dlm/lock.c
+++ b/fs/dlm/lock.c
@@ -580,9 +580,8 @@ static void detach_lkb(struct dlm_lkb *lkb)
 
 static int create_lkb(struct dlm_ls *ls, struct dlm_lkb **lkb_ret)
 {
-	struct dlm_lkb *lkb, *tmp;
-	uint32_t lkid = 0;
-	uint16_t bucket;
+	struct dlm_lkb *lkb;
+	int rv, id;
 
 	lkb = dlm_allocate_lkb(ls);
 	if (!lkb)
@@ -596,58 +595,38 @@ static int create_lkb(struct dlm_ls *ls, struct dlm_lkb **lkb_ret)
 	INIT_LIST_HEAD(&lkb->lkb_time_list);
 	INIT_LIST_HEAD(&lkb->lkb_astqueue);
 
-	get_random_bytes(&bucket, sizeof(bucket));
-	bucket &= (ls->ls_lkbtbl_size - 1);
-
-	write_lock(&ls->ls_lkbtbl[bucket].lock);
+ retry:
+	rv = idr_pre_get(&ls->ls_lkbidr, GFP_NOFS);
+	if (!rv)
+		return -ENOMEM;
 
-	/* counter can roll over so we must verify lkid is not in use */
+	spin_lock(&ls->ls_lkbidr_spin);
+	rv = idr_get_new_above(&ls->ls_lkbidr, lkb, 1, &id);
+	if (!rv)
+		lkb->lkb_id = id;
+	spin_unlock(&ls->ls_lkbidr_spin);
 
-	while (lkid == 0) {
-		lkid = (bucket << 16) | ls->ls_lkbtbl[bucket].counter++;
+	if (rv == -EAGAIN)
+		goto retry;
 
-		list_for_each_entry(tmp, &ls->ls_lkbtbl[bucket].list,
-				    lkb_idtbl_list) {
-			if (tmp->lkb_id != lkid)
-				continue;
-			lkid = 0;
-			break;
-		}
+	if (rv < 0) {
+		log_error(ls, "create_lkb idr error %d", rv);
+		return rv;
 	}
 
-	lkb->lkb_id = lkid;
-	list_add(&lkb->lkb_idtbl_list, &ls->ls_lkbtbl[bucket].list);
-	write_unlock(&ls->ls_lkbtbl[bucket].lock);
-
 	*lkb_ret = lkb;
 	return 0;
 }
 
-static struct dlm_lkb *__find_lkb(struct dlm_ls *ls, uint32_t lkid)
-{
-	struct dlm_lkb *lkb;
-	uint16_t bucket = (lkid >> 16);
-
-	list_for_each_entry(lkb, &ls->ls_lkbtbl[bucket].list, lkb_idtbl_list) {
-		if (lkb->lkb_id == lkid)
-			return lkb;
-	}
-	return NULL;
-}
-
 static int find_lkb(struct dlm_ls *ls, uint32_t lkid, struct dlm_lkb **lkb_ret)
 {
 	struct dlm_lkb *lkb;
-	uint16_t bucket = (lkid >> 16);
-
-	if (bucket >= ls->ls_lkbtbl_size)
-		return -EBADSLT;
 
-	read_lock(&ls->ls_lkbtbl[bucket].lock);
-	lkb = __find_lkb(ls, lkid);
+	spin_lock(&ls->ls_lkbidr_spin);
+	lkb = idr_find(&ls->ls_lkbidr, lkid);
 	if (lkb)
 		kref_get(&lkb->lkb_ref);
-	read_unlock(&ls->ls_lkbtbl[bucket].lock);
+	spin_unlock(&ls->ls_lkbidr_spin);
 
 	*lkb_ret = lkb;
 	return lkb ? 0 : -ENOENT;
@@ -668,12 +647,12 @@ static void kill_lkb(struct kref *kref)
 
 static int __put_lkb(struct dlm_ls *ls, struct dlm_lkb *lkb)
 {
-	uint16_t bucket = (lkb->lkb_id >> 16);
+	uint32_t lkid = lkb->lkb_id;
 
-	write_lock(&ls->ls_lkbtbl[bucket].lock);
+	spin_lock(&ls->ls_lkbidr_spin);
 	if (kref_put(&lkb->lkb_ref, kill_lkb)) {
-		list_del(&lkb->lkb_idtbl_list);
-		write_unlock(&ls->ls_lkbtbl[bucket].lock);
+		idr_remove(&ls->ls_lkbidr, lkid);
+		spin_unlock(&ls->ls_lkbidr_spin);
 
 		detach_lkb(lkb);
 
@@ -683,7 +662,7 @@ static int __put_lkb(struct dlm_ls *ls, struct dlm_lkb *lkb)
 		dlm_free_lkb(lkb);
 		return 1;
 	} else {
-		write_unlock(&ls->ls_lkbtbl[bucket].lock);
+		spin_unlock(&ls->ls_lkbidr_spin);
 		return 0;
 	}
 }