We need to incorporate some code from upstream Linux into the
Xen/ia64 tree that makes use of hlists. The lineage of the current
list.h in the Xen tree is hard to determine, so the most straightforward
approach to adding hlists seems to be taking the chunk we need from
current upstream Linux. The patch below pulls in the hlist support (not
including rcu or poisoning). Is this reasonable or should we think
about updating all of list.h to something newer? Thanks,
Alex
Signed-off-by: Alex Williamson <alex.williamson@hp.com>
---
diff -r 5a68672cee38 xen/include/xen/list.h
--- a/xen/include/xen/list.h Thu Dec 14 13:29:17 2006 -0700
+++ b/xen/include/xen/list.h Thu Dec 14 14:26:36 2006 -0700
@@ -196,5 +196,153 @@ static __inline__ void list_splice(struc
n = list_entry(pos->member.next, typeof(*pos), member); \
&pos->member != (head); \
pos = n, n = list_entry(n->member.next, typeof(*n), member))
+
+/*
+ * Double linked lists with a single pointer list head.
+ * Mostly useful for hash tables where the two pointer list head is
+ * too wasteful.
+ * You lose the ability to access the tail in O(1).
+ */
+
+struct hlist_head {
+ struct hlist_node *first;
+};
+
+struct hlist_node {
+ struct hlist_node *next, **pprev;
+};
+
+#define HLIST_HEAD_INIT { .first = NULL }
+#define HLIST_HEAD(name) struct hlist_head name = { .first = NULL }
+#define INIT_HLIST_HEAD(ptr) ((ptr)->first = NULL)
+static inline void INIT_HLIST_NODE(struct hlist_node *h)
+{
+ h->next = NULL;
+ h->pprev = NULL;
+}
+
+static inline int hlist_unhashed(const struct hlist_node *h)
+{
+ return !h->pprev;
+}
+
+static inline int hlist_empty(const struct hlist_head *h)
+{
+ return !h->first;
+}
+
+static inline void __hlist_del(struct hlist_node *n)
+{
+ struct hlist_node *next = n->next;
+ struct hlist_node **pprev = n->pprev;
+ *pprev = next;
+ if (next)
+ next->pprev = pprev;
+}
+
+static inline void hlist_del(struct hlist_node *n)
+{
+ __hlist_del(n);
+}
+
+static inline void hlist_del_init(struct hlist_node *n)
+{
+ if (!hlist_unhashed(n)) {
+ __hlist_del(n);
+ INIT_HLIST_NODE(n);
+ }
+}
+
+static inline void hlist_add_head(struct hlist_node *n, struct hlist_head *h)
+{
+ struct hlist_node *first = h->first;
+ n->next = first;
+ if (first)
+ first->pprev = &n->next;
+ h->first = n;
+ n->pprev = &h->first;
+}
+
+/* next must be != NULL */
+static inline void hlist_add_before(struct hlist_node *n,
+ struct hlist_node *next)
+{
+ n->pprev = next->pprev;
+ n->next = next;
+ next->pprev = &n->next;
+ *(n->pprev) = n;
+}
+
+static inline void hlist_add_after(struct hlist_node *n,
+ struct hlist_node *next)
+{
+ next->next = n->next;
+ n->next = next;
+ next->pprev = &n->next;
+
+ if(next->next)
+ next->next->pprev = &next->next;
+}
+
+#define hlist_entry(ptr, type, member) container_of(ptr,type,member)
+
+#define hlist_for_each(pos, head) \
+ for (pos = (head)->first; pos && ({ prefetch(pos->next); 1; });
\
+ pos = pos->next)
+
+#define hlist_for_each_safe(pos, n, head) \
+ for (pos = (head)->first; pos && ({ n = pos->next; 1; }); \
+ pos = n)
+
+/**
+ * hlist_for_each_entry - iterate over list of given type
+ * @tpos: the type * to use as a loop cursor.
+ * @pos: the &struct hlist_node to use as a loop cursor.
+ * @head: the head for your list.
+ * @member: the name of the hlist_node within the struct.
+ */
+#define hlist_for_each_entry(tpos, pos, head, member) \
+ for (pos = (head)->first; \
+ pos && ({ prefetch(pos->next); 1;}) && \
+ ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
+ pos = pos->next)
+
+/**
+ * hlist_for_each_entry_continue - iterate over a hlist continuing after
current point
+ * @tpos: the type * to use as a loop cursor.
+ * @pos: the &struct hlist_node to use as a loop cursor.
+ * @member: the name of the hlist_node within the struct.
+ */
+#define hlist_for_each_entry_continue(tpos, pos, member) \
+ for (pos = (pos)->next; \
+ pos && ({ prefetch(pos->next); 1;}) && \
+ ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
+ pos = pos->next)
+
+/**
+ * hlist_for_each_entry_from - iterate over a hlist continuing from current
point
+ * @tpos: the type * to use as a loop cursor.
+ * @pos: the &struct hlist_node to use as a loop cursor.
+ * @member: the name of the hlist_node within the struct.
+ */
+#define hlist_for_each_entry_from(tpos, pos, member) \
+ for (; pos && ({ prefetch(pos->next); 1;}) && \
+ ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
+ pos = pos->next)
+
+/**
+ * hlist_for_each_entry_safe - iterate over list of given type safe against
removal of list entry
+ * @tpos: the type * to use as a loop cursor.
+ * @pos: the &struct hlist_node to use as a loop cursor.
+ * @n: another &struct hlist_node to use as temporary storage
+ * @head: the head for your list.
+ * @member: the name of the hlist_node within the struct.
+ */
+#define hlist_for_each_entry_safe(tpos, pos, n, head, member) \
+ for (pos = (head)->first; \
+ pos && ({ n = pos->next; 1; }) && \
+ ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
+ pos = n)
+
#endif /* _LINUX_LIST_H */
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