[Sheepdog] [PATCH 5/5] sheep: add hlist candy helpers

[Liu Yuan]

From: Liu Yuan <tailai.ly at taobao.com>

Taken from Linux kernel.

Signed-off-by: Liu Yuan <tailai.ly at taobao.com>
---
 include/list.h |  116 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 116 insertions(+), 0 deletions(-)

diff --git a/include/list.h b/include/list.h
index 599ee9b..c1d5939 100644
--- a/include/list.h
+++ b/include/list.h
@@ -114,4 +114,120 @@ static inline void list_splice_init(struct list_head *list,
 		INIT_LIST_HEAD(list);
 	}
 }
+
+/* hlist, mostly useful for hash tables */
+
+#define LIST_POISON1 ((void *) 0x00100100)
+#define LIST_POISON2 ((void *) 0x00200200)
+
+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);
+        n->next = LIST_POISON1;
+        n->pprev = LIST_POISON2;
+}
+
+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 ; 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 &&                                                      \
+                ({ 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
-- 
1.7.6.1