[SSI] openssi/kernel/cluster/ssi/token msgsup.c,1.9,1.10

Update of /cvsroot/ssic-linux/openssi/kernel/cluster/ssi/token
In directory sfp-cvsdas-3.v30.ch3.sourceforge.com:/tmp/cvs-serv14589/cluster/ssi/token

Modified Files:
      Tag: OPENSSI-FC
	msgsup.c 
Log Message:
* CFS:
- Disable sharing mode detection flags. They were never used.

* CFS Token Architecture (#ifdef RCU_MSGSUP_HASH):
- In process_msgs() function 
  - Fix did not handle -EREMOTE from TRANSPORT(); error was discarded
    and token never got to server.
  - Remove "goto" statements.
- cfstok_send() optimize away RPC if server is down; just return
  -EREMOTE.


Index: msgsup.c
===================================================================
RCS file: /cvsroot/ssic-linux/openssi/kernel/cluster/ssi/token/msgsup.c,v
retrieving revision 1.9
retrieving revision 1.10
diff -u -d -r1.9 -r1.10
--- msgsup.c	27 Oct 2009 03:18:29 -0000	1.9
+++ msgsup.c	2 Feb 2010 04:31:45 -0000	1.10
@@ -127,7 +127,7 @@
 	long id;
 #endif
 #ifdef RCU_MSGSUP_HASH
-	int in_process_msgs; /* non-zero: being processed by process_msgs() */
+	unsigned int in_process_msgs; /* non-zero: in process_msgs() */
 #endif
 	object_t obj;
 	int op;
@@ -491,14 +491,68 @@
 process_msgs(int force)
 {
 	struct msg *save;
+#ifdef RCU_MSGSUP
 #ifdef RCU_MSGSUP_HASH
 	unsigned long hashval = MSG_HASH;
+#ifdef DEBUG
 	int recurse = FALSE;
-#else
+#endif
+	int error;
+
+	for (;;) {
+		error = -ENOENT;
+		rcu_read_lock();
+		list_for_each_entry_rcu(save,
+					&msgsup_hashtable[hashval], msg_list) {
+			if (save->id != NSC_UNIQUE_ID)
+				continue;
+			/* Linux: No race because NSC_UNIQUE_ID == current */
+			if (!save->in_process_msgs) {
+				save->in_process_msgs = 1;
+				error = 0;
+				break;
+			}
+			/* Called from process_msgs() path. */
+			if (!force)
+				break; /* Skip recursive process_msgs() */
+#ifdef DEBUG
+			WARN_ON(save->in_process_msgs++ > 16);
+			recurse = TRUE;
+#endif
+			continue;
+		}
+		rcu_read_unlock();
+		if (error)
+			return;
+#ifdef DEBUG
+		if (recurse)
+			printk(KERN_WARNING
+			    "%s: forced recursive processing\n", __FUNCTION__);
+#endif
+
+		error = TRANSPORT(&save->obj)(&save->obj, save->seq, save->op,
+				save->oldmode, save->newmode, save->agent,
+				save->start, save->len);
+		if (error == -EREMOTE) {
+			save->in_process_msgs = 0;
+			idelay(HZ);
+			continue;
+		}
+		SSI_ASSERT(!error);
+
+		/* Remove from list only after successful TRANSPORT()
+		 * so that process_msgs() can detect recursive processing.
+		 */
+		MSG_LOCK(msg_lock);
+		list_del_rcu(&save->msg_list);
+		MSG_UNLOCK(msg_lock);
+
+		call_rcu(&save->msg_rcu, msgsup_free);
+	}
+#else /* RCU_MSGSUP_HASH */
 	int recurse;
 
 	/* PERF: Optimize NOOP case */
-#ifdef RCU_MSGSUP
 	rcu_read_lock();
 	list_for_each_entry_rcu(save, &msgsup_head, msg_list) {
 		if (save->id == NSC_UNIQUE_ID)
@@ -512,70 +566,14 @@
 	if (recurse) {
 		if (!force)
 			return;
-#else /* !RCU_MSGSUP */
-	if (msgsup_head == NULL)
-		return;
-
-	MSG_LOCK(msg_lock);
-
-	recurse = FALSE;
-	if (msgsup_findid(NSC_UNIQUE_ID)) {
-		if (!force) {
-			MSG_UNLOCK(msg_lock);
-			return;
-		}
-
-		recurse = TRUE;
-#endif /* !RCU_MSGSUP */
 #ifdef DEBUG
 		printk(KERN_WARNING
 		    "process_msgs: forced recursive processing\n");
 #endif
 	} else
 		msgsup_addid(NSC_UNIQUE_ID);
-#endif /* !RCU_MSGSUP_HASH */
 
 restart:
-#ifdef RCU_MSGSUP
-#ifdef RCU_MSGSUP_HASH
-	rcu_read_lock();
-	list_for_each_entry_rcu(save, &msgsup_hashtable[hashval], msg_list) {
-		if (save->id != NSC_UNIQUE_ID)
-			continue;
-		/* SSI: No race. NSC_UNIQUE_ID == current */
-		if (save->in_process_msgs) {
-			if (!recurse) {
-				if (!force)
-					break;
-				WARN_ON(save->in_process_msgs++ > 16);
-				recurse = TRUE;
-			}
-			/* already being processed */
-			continue;
-		}
-		save->in_process_msgs = 1;
-		rcu_read_unlock();
-
-#ifdef DEBUG
-		if (recurse)
-			printk(KERN_WARNING
-			    "%s: forced recursive processing\n", __FUNCTION__);
-#endif
-
-		TRANSPORT((&(save->obj)))(&(save->obj), save->seq,
-			save->op, save->oldmode, save->newmode, save->agent,
-			save->start, save->len);
-
-		/* Only remove from list after recursive processing. */
-		MSG_LOCK(msg_lock);
-		list_del_rcu(&save->msg_list);
-		MSG_UNLOCK(msg_lock);
-
-		call_rcu(&save->msg_rcu, msgsup_free);
-		goto restart;
-	}
-	rcu_read_unlock();
-#else /* !RCU_MSGSUP_HASH */
 	rcu_read_lock();
 	list_for_each_entry_rcu(save, &msgsup_head, msg_list) {
 		if (save->id != NSC_UNIQUE_ID)
@@ -606,7 +604,31 @@
 	}
 	rcu_read_unlock();
 #endif /* !RCU_MSGSUP_HASH */
-#else /* !RCU_MSGSUP */
+#else /* RCU_MSGSUP */
+	int recurse;
+
+	/* PERF: Optimize NOOP case */
+	if (msgsup_head == NULL)
+		return;
+
+	MSG_LOCK(msg_lock);
+
+	recurse = FALSE;
+	if (msgsup_findid(NSC_UNIQUE_ID)) {
+		if (!force) {
+			MSG_UNLOCK(msg_lock);
+			return;
+		}
+
+		recurse = TRUE;
+#ifdef DEBUG
+		printk(KERN_WARNING
+		    "process_msgs: forced recursive processing\n");
+#endif
+	} else
+		msgsup_addid(NSC_UNIQUE_ID);
+
+restart:
 	for (save = msgsup_head ; save ; save = save->next) {
 
 		if (save->id != NSC_UNIQUE_ID) {


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