From fbf4d7e3d03587a983ee4e536251ea6c1c848ec2 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] RDS: Remove unused XLIST_PTR_TAIL and xlist_protect()
Not used.
Signed-off-by: Andy Grover <andy.grover@oracle.com>
---
net/rds/xlist.h | 54 +++++++++++--------------------------------------
1 file changed, 12 insertions(+), 42 deletions(-)
diff --git a/net/rds/xlist.h b/net/rds/xlist.h
index 8c21aca49d50..e6b5190daddd 100644
--- a/net/rds/xlist.h
+++ b/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
--
GitLab