From 4c846abb6203e17881d5935437b33bd08f3d5820 Mon Sep 17 00:00:00 2001
From: Andy Grover <andy.grover@oracle.com>
Date: Fri, 11 Jun 2010 16:24:42 -0700
Subject: [PATCH] --- yaml --- r: 214451 b: refs/heads/master c:
 fbf4d7e3d03587a983ee4e536251ea6c1c848ec2 h: refs/heads/master i:   214449:
 7bfd4db002b09127c77600222f72fd1bbe4e4dc4   214447:
 6a26a0482d564fd266b8fd487bc80e9d44adeaed v: v3

---
 [refs]                |  2 +-
 trunk/net/rds/xlist.h | 54 ++++++++++---------------------------------
 2 files changed, 13 insertions(+), 43 deletions(-)

diff --git a/[refs] b/[refs]
index 8a8352e7d055..7d9e4860b267 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: c9455d9996ba84af1f534c7e3944ea6f35d2fc54
+refs/heads/master: fbf4d7e3d03587a983ee4e536251ea6c1c848ec2
diff --git a/trunk/net/rds/xlist.h b/trunk/net/rds/xlist.h
index 8c21aca49d50..e6b5190daddd 100644
--- a/trunk/net/rds/xlist.h
+++ b/trunk/net/rds/xlist.h
@@ -10,13 +10,18 @@ struct xlist_head {
 	struct xlist_head *next;
 };
 
-/*
- * XLIST_PTR_TAIL can be used to prevent double insertion.  See
- * xlist_protect()
- */
-#define XLIST_PTR_TAIL ((struct xlist_head *)0x1)
+static inline void INIT_XLIST_HEAD(struct xlist_head *list)
+{
+	list->next = NULL;
+}
+
+static inline int xlist_empty(struct xlist_head *head)
+{
+	return head->next == NULL;
+}
 
-static inline void xlist_add(struct xlist_head *new, struct xlist_head *tail, struct xlist_head *head)
+static inline void xlist_add(struct xlist_head *new, struct xlist_head *tail,
+			     struct xlist_head *head)
 {
 	struct xlist_head *cur;
 	struct xlist_head *check;
@@ -30,26 +35,6 @@ static inline void xlist_add(struct xlist_head *new, struct xlist_head *tail, st
 	}
 }
 
-/*
- * To avoid duplicate insertion by two CPUs of the same xlist item
- * you can call xlist_protect.  It will stuff XLIST_PTR_TAIL
- * into the entry->next pointer with xchg, and only return 1
- * if there was a NULL there before.
- *
- * if xlist_protect returns zero, someone else is busy working
- * on this entry.  Getting a NULL into the entry in a race
- * free manner is the caller's job.
- */
-static inline int xlist_protect(struct xlist_head *entry)
-{
-	struct xlist_head *val;
-
-	val = xchg(&entry->next, XLIST_PTR_TAIL);
-	if (val == NULL)
-		return 1;
-	return 0;
-}
-
 static inline struct xlist_head *xlist_del_head(struct xlist_head *head)
 {
 	struct xlist_head *cur;
@@ -61,11 +46,6 @@ static inline struct xlist_head *xlist_del_head(struct xlist_head *head)
 		if (!cur)
 			goto out;
 
-		if (cur == XLIST_PTR_TAIL) {
-			cur = NULL;
-			goto out;
-		}
-
 		next = cur->next;
 		check = cmpxchg(&head->next, cur, next);
 		if (check == cur)
@@ -80,7 +60,7 @@ static inline struct xlist_head *xlist_del_head_fast(struct xlist_head *head)
 	struct xlist_head *cur;
 
 	cur = head->next;
-	if (!cur || cur == XLIST_PTR_TAIL)
+	if (!cur)
 		return NULL;
 
 	head->next = cur->next;
@@ -97,14 +77,4 @@ static inline void xlist_splice(struct xlist_head *list,
 	head->next = cur;
 }
 
-static inline void INIT_XLIST_HEAD(struct xlist_head *list)
-{
-	list->next = NULL;
-}
-
-static inline int xlist_empty(struct xlist_head *head)
-{
-	return head->next == NULL || head->next == XLIST_PTR_TAIL;
-}
-
 #endif