dlm: switch to use rhashtable for rsbs

Replace our own hash table with the more advanced rhashtable
for keeping rsb structs.

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

Author: Alexander Aring

fs/dlm/config.c

@@ -63,6 +63,14 @@ static void release_node(struct config_item *);
 static struct configfs_attribute *comm_attrs[];
 static struct configfs_attribute *node_attrs[];
 
+const struct rhashtable_params dlm_rhash_rsb_params = {
+	.nelem_hint = 3, /* start small */
+	.key_len = DLM_RESNAME_MAXLEN,
+	.key_offset = offsetof(struct dlm_rsb, res_name),
+	.head_offset = offsetof(struct dlm_rsb, res_node),
+	.automatic_shrinking = true,
+};
+
 struct dlm_cluster {
 	struct config_group group;
 	unsigned int cl_tcp_port;

fs/dlm/config.h

@@ -21,6 +21,8 @@ struct dlm_config_node {
 	uint32_t comm_seq;
 };
 
+extern const struct rhashtable_params dlm_rhash_rsb_params;
+
 #define DLM_MAX_ADDR_COUNT 3
 
 #define DLM_PROTO_TCP	0

fs/dlm/dir.c

@@ -198,14 +198,10 @@ static struct dlm_rsb *find_rsb_root(struct dlm_ls *ls, const char *name,
 				     int len)
 {
 	struct dlm_rsb *r;
-	uint32_t hash, bucket;
 	int rv;
 
-	hash = jhash(name, len, 0);
-	bucket = hash & (ls->ls_rsbtbl_size - 1);
-
 	spin_lock_bh(&ls->ls_rsbtbl_lock);
-	rv = dlm_search_rsb_tree(&ls->ls_rsbtbl[bucket].r, name, len, &r);
+	rv = dlm_search_rsb_tree(&ls->ls_rsbtbl, name, len, &r);
 	spin_unlock_bh(&ls->ls_rsbtbl_lock);
 	if (!rv)
 		return r;

fs/dlm/dlm_internal.h

@@ -34,6 +34,7 @@
 #include <linux/kernel.h>
 #include <linux/jhash.h>
 #include <linux/miscdevice.h>
+#include <linux/rhashtable.h>
 #include <linux/mutex.h>
 #include <linux/idr.h>
 #include <linux/ratelimit.h>
@@ -99,15 +100,6 @@ do { \
   } \
 }
 
-
-#define DLM_RTF_SHRINK_BIT	0
-
-struct dlm_rsbtable {
-	struct rb_root          r;
-	unsigned long		flags;
-};
-
-
 /*
  * Lockspace member (per node in a ls)
  */
@@ -327,13 +319,12 @@ struct dlm_rsb {
 	int			res_id;		/* for ls_recover_idr */
 	uint32_t                res_lvbseq;
 	uint32_t		res_hash;
-	uint32_t		res_bucket;	/* rsbtbl */
 	unsigned long		res_toss_time;
 	uint32_t		res_first_lkid;
 	struct list_head	res_lookup;	/* lkbs waiting on first */
 	union {
 		struct list_head	res_hashchain;
-		struct rb_node		res_hashnode;	/* rsbtbl */
+		struct rhash_head	res_node; /* rsbtbl */
 	};
 	struct list_head	res_grantqueue;
 	struct list_head	res_convertqueue;
@@ -592,9 +583,10 @@ struct dlm_ls {
 	struct idr		ls_lkbidr;
 	spinlock_t		ls_lkbidr_spin;
 
-	struct dlm_rsbtable	*ls_rsbtbl;
+	struct rhashtable	ls_rsbtbl;
+#define DLM_RTF_SHRINK_BIT	0
+	unsigned long		ls_rsbtbl_flags;
 	spinlock_t		ls_rsbtbl_lock;
-	uint32_t		ls_rsbtbl_size;
 
 	struct list_head	ls_toss;
 	struct list_head	ls_keep;