[SSI] openssi/kernel/cluster/ssi/cfs svrcfs.c,1.27,1.28

Update of /cvsroot/ssic-linux/openssi/kernel/cluster/ssi/cfs
In directory sfp-cvsdas-3.v30.ch3.sourceforge.com:/tmp/cvs-serv3991/cluster/ssi/cfs

Modified Files:
      Tag: OPENSSI-FC
	svrcfs.c 
Log Message:
CFS (#ifdef RCU_CFSTOK_TABLE):
- Remove sct_statelock spinlock in struct svrcfstok reference counting
  code. Use atomic_test_and_add().
- sct_magic is no longer used except for debugging. (#ifdef DEBUG)
- sct_prlist is no longer used in svrcfstok_nodedown since the final
  HASH_RELE() releases svrcfstok structure.

 cluster/ssi/cfs/svrcfs.c         |   98 ++++++++-----------------------
 include/cluster/ssi/cfs/cfstok.h |   14 +++-
 2 files changed, 38 insertions(+), 74 deletions(-)


Index: svrcfs.c
===================================================================
RCS file: /cvsroot/ssic-linux/openssi/kernel/cluster/ssi/cfs/svrcfs.c,v
retrieving revision 1.27
retrieving revision 1.28
diff -u -d -r1.27 -r1.28
--- svrcfs.c	17 Dec 2009 06:43:50 -0000	1.27
+++ svrcfs.c	5 Mar 2010 06:07:00 -0000	1.28
@@ -243,34 +243,10 @@
 static inline struct svrcfstok *
 __hash_hold_and_check(svrcfstok_t *hp)
 {
-	LOCK_COND_LOCK(&hp->sct_statelock);
-	if (hp->sct_magic != CFSTOK_MAGIC) {
-		UNLOCK_COND_LOCK(&hp->sct_statelock);
+	if (!atomic_test_and_add(1, &hp->sct_refcnt))
 		return NULL;
-	}
-	HASH_HOLD(hp);
-	UNLOCK_COND_LOCK(&hp->sct_statelock);
 	return hp;
 }
-
-#ifdef DEBUG
-static int
-hash_hold_and_check(svrcfstok_t *hp)
-{
-	struct svrcfstok *h;
-
-	rcu_read_lock();
-	if (hp->sct_magic != CFSTOK_MAGIC) {
-		rcu_read_unlock();
-		return 0;
-	}
-
-	h = __hash_hold_and_check(hp);
-	rcu_read_unlock();
-
-	return (h != NULL);
-}
-#endif /* DEBUG */
 #endif
 
 /*
@@ -455,7 +431,9 @@
 		INIT_RCU_HEAD(&hp->sct_rcu);
 #endif
 		atomic_set(&hp->sct_refcnt, 1);
+#ifdef DEBUG
 		hp->sct_magic = CFSTOK_MAGIC;
+#endif
 #else
 		hp->sct_refcnt = 1;
 #endif /* !RCU_CFSTOK_TABLE */
@@ -470,7 +448,7 @@
 		INIT_CONDITION(&hp->sct_cond);
 		INIT_RW_LOCK(&hp->sct_objlock);
 #endif /* !SVRCFS_TOKEN_KMEM_CACHE */
-#if !defined(CFSTOK_TABLE_LOCK_LOCK) || defined(RCU_CFSTOK_TABLE)
+#if !defined(CFSTOK_TABLE_LOCK_LOCK) && !defined(RCU_CFSTOK_TABLE)
 		INIT_LIST_HEAD(&(hp->sct_prlist));
 #endif
 
@@ -664,17 +642,14 @@
 #ifdef RCU_CFSTOK_TABLE
 	might_sleep_if(atomic_read(&hp->sct_refcnt) == 1);
 	if (!atomic_dec_and_lock(&hp->sct_refcnt, &svrcfstok_table_lock)) {
-		/* WARN_ON(atomic_read(&hp->sct_refcnt) < 0); */
-		return;
-	}
-	LOCK_COND_LOCK(&hp->sct_statelock);
-	if (atomic_read(&hp->sct_refcnt)) {
-		UNLOCK_COND_LOCK(&hp->sct_statelock);
-		spin_unlock(&svrcfstok_table_lock);
+#ifdef DEBUG
+		WARN_ON(atomic_read(&hp->sct_refcnt) < 0);
+#endif
 		return;
 	}
+#ifdef DEBUG
 	hp->sct_magic = 0;
-	UNLOCK_COND_LOCK(&hp->sct_statelock);
+#endif
 	hlist_del_rcu(&hp->sct_hlist);
 	spin_unlock(&svrcfstok_table_lock);
 
@@ -1053,14 +1028,9 @@
 svrcfstok_hold_obj(object_t *objp)
 {
 #ifdef DEBUG
-#ifdef RCU_CFSTOK_TABLE
-	BUG_ON(!hash_hold_and_check((struct svrcfstok *) objp->word1));
-#else
-#error not supported
+	BUG_ON(((struct svrcfstok *)objp->word1)->sct_magic != CFSTOK_MAGIC);
 #endif
-#else
 	HASH_HOLD((struct svrcfstok *) objp->word1);
-#endif /* !DEBUG */
 }
 
 /*
@@ -2773,25 +2743,26 @@
 	u_long hash;
 #endif
 	struct svrcfstok *hp;  	/* Pointer to server token structure. */
-	struct svrcfstok *hp_next; /* Saved pointer to next structure. */
 #ifdef RCU_CFSTOK_TABLE
 	struct hlist_node *pos;
+#ifdef DEBUG
+	struct svrcfstok *hp_next; /* Saved pointer to next structure. */
 	u_long count = 0;
 #endif
-	int doagain;
-	int retry_count = 0;
-#if !defined(CFSTOK_TABLE_LOCK_LOCK) || defined(RCU_CFSTOK_TABLE)
+#else
+	struct svrcfstok *hp_next; /* Saved pointer to next structure. */
+#endif /* !RCU_CFSTOK_TABLE */
+	int doagain, retry_count = 0;
+#if !defined(CFSTOK_TABLE_LOCK_LOCK) && !defined(RCU_CFSTOK_TABLE)
 	LIST_HEAD(tofree_head);
 #endif
 #ifndef CFSTOK_TABLE_LOCK_LOCK
 	struct list_head *act_head;
 #endif
 
-	SSI_ASSERT(sb != NULL);
-	SSI_ASSERT(cfs_sb_is_cfs(sb));
+	SSI_ASSERT(sb && cfs_sb_is_cfs(sb));
 retry:
 	doagain = FALSE;
-	/* Release all token structures belonging to this SB. */
 #ifdef RCU_CFSTOK_TABLE
 	for (hash = 0; hash < HASHSIZ; hash++) {
 		rcu_read_lock();
@@ -2799,34 +2770,16 @@
 			if (hp->sct_sb == sb) {
 				if (atomic_read(&hp->sct_refcnt)) {
 					doagain = TRUE;
-					continue;
-				}
-				LOCK_COND_LOCK(&hp->sct_statelock);
-				if (atomic_read(&hp->sct_refcnt)) {
-					UNLOCK_COND_LOCK(&hp->sct_statelock);
-					BUG_ON(atomic_read(&hp->sct_refcnt) < 0);
-					doagain = TRUE;
-					continue;
+					break;
 				}
-				hp->sct_magic = 0;
-				UNLOCK_COND_LOCK(&hp->sct_statelock);
-				spin_lock(&svrcfstok_table_lock);
-				hlist_del_rcu(&hp->sct_hlist);
-				spin_unlock(&svrcfstok_table_lock);
-				list_add(&hp->sct_prlist, &tofree_head);
+				/* SSI: There is no need to release struct
+				 * because the only way sct_refcnt gets to zero
+				 * is HASH_RELE() which calls svrtok_dorelse().
+				 *	-Roger
+				 */
 			}
 		}
 		rcu_read_unlock();
-		list_for_each_entry_safe(hp, hp_next, &tofree_head, sct_prlist) {
-			list_del(&hp->sct_prlist);
-			svrtok_dorelse(hp, TRUE);
-			count++;
-		}
-		if (unlikely(count)) {
-			printk(KERN_WARNING "%s: found %lu stale token"
-					" structures\n", __FUNCTION__, count);
-			count = 0;
-		}
 	}
 	if (doagain) {
 		if (++retry_count == 5) {
@@ -2837,7 +2790,8 @@
 		nidelay(HZ/10);
 		goto retry;
 	}
-#else /* !RCU_CFSTOK_TABLE */
+#else /* RCU_CFSTOK_TABLE */
+	/* Release all token structures belonging to this SB. */
 	LOCK_LOCK(&svrcfstok_table_lock);
 	for (hash = 0; hash < HASHSIZ; hash++) {
 		hp_next = svrcfs_hash_table[hash];


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