* RCU-protected list version
*/
#include <linux/list.h>
+#include <linux/rcupdate.h>
/*
* Insert a new entry between two known consecutive entries.
{
new->next = next;
new->prev = prev;
- smp_wmb();
+ rcu_assign_pointer(prev->next, new);
next->prev = new;
- prev->next = new;
}
/**
entry->prev = LIST_POISON2;
}
+/**
+ * hlist_del_init_rcu - deletes entry from hash list with re-initialization
+ * @n: the element to delete from the hash list.
+ *
+ * Note: list_unhashed() on the node return true after this. It is
+ * useful for RCU based read lockfree traversal if the writer side
+ * must know if the list entry is still hashed or already unhashed.
+ *
+ * In particular, it means that we can not poison the forward pointers
+ * that may still be used for walking the hash list and we can only
+ * zero the pprev pointer so list_unhashed() will return true after
+ * this.
+ *
+ * The caller must take whatever precautions are necessary (such as
+ * holding appropriate locks) to avoid racing with another
+ * list-mutation primitive, such as hlist_add_head_rcu() or
+ * hlist_del_rcu(), running on this same list. However, it is
+ * perfectly legal to run concurrently with the _rcu list-traversal
+ * primitives, such as hlist_for_each_entry_rcu().
+ */
+static inline void hlist_del_init_rcu(struct hlist_node *n)
+{
+ if (!hlist_unhashed(n)) {
+ __hlist_del(n);
+ n->pprev = NULL;
+ }
+}
+
/**
* list_replace_rcu - replace old entry by new one
* @old : the element to be replaced
{
new->next = old->next;
new->prev = old->prev;
- smp_wmb();
+ rcu_assign_pointer(new->prev->next, new);
new->next->prev = new;
- new->prev->next = new;
old->prev = LIST_POISON2;
}
*/
last->next = at;
- smp_wmb();
- head->next = first;
+ rcu_assign_pointer(head->next, first);
first->prev = head;
at->prev = last;
}
* as long as the traversal is guarded by rcu_read_lock().
*/
#define list_for_each_rcu(pos, head) \
- for (pos = (head)->next; \
- prefetch(rcu_dereference(pos)->next), pos != (head); \
- pos = pos->next)
+ for (pos = rcu_dereference((head)->next); \
+ prefetch(pos->next), pos != (head); \
+ pos = rcu_dereference(pos->next))
#define __list_for_each_rcu(pos, head) \
- for (pos = (head)->next; \
- rcu_dereference(pos) != (head); \
- pos = pos->next)
-
-/**
- * list_for_each_safe_rcu
- * @pos: the &struct list_head to use as a loop cursor.
- * @n: another &struct list_head to use as temporary storage
- * @head: the head for your list.
- *
- * Iterate over an rcu-protected list, safe against removal of list entry.
- *
- * This list-traversal primitive may safely run concurrently with
- * the _rcu list-mutation primitives such as list_add_rcu()
- * as long as the traversal is guarded by rcu_read_lock().
- */
-#define list_for_each_safe_rcu(pos, n, head) \
- for (pos = (head)->next; \
- n = rcu_dereference(pos)->next, pos != (head); \
- pos = n)
+ for (pos = rcu_dereference((head)->next); \
+ pos != (head); \
+ pos = rcu_dereference(pos->next))
/**
* list_for_each_entry_rcu - iterate over rcu list of given type
* as long as the traversal is guarded by rcu_read_lock().
*/
#define list_for_each_entry_rcu(pos, head, member) \
- for (pos = list_entry((head)->next, typeof(*pos), member); \
- prefetch(rcu_dereference(pos)->member.next), \
- &pos->member != (head); \
- pos = list_entry(pos->member.next, typeof(*pos), member))
+ for (pos = list_entry(rcu_dereference((head)->next), typeof(*pos), member); \
+ prefetch(pos->member.next), &pos->member != (head); \
+ pos = list_entry(rcu_dereference(pos->member.next), typeof(*pos), member))
/**
* as long as the traversal is guarded by rcu_read_lock().
*/
#define list_for_each_continue_rcu(pos, head) \
- for ((pos) = (pos)->next; \
- prefetch(rcu_dereference((pos))->next), (pos) != (head); \
- (pos) = (pos)->next)
+ for ((pos) = rcu_dereference((pos)->next); \
+ prefetch((pos)->next), (pos) != (head); \
+ (pos) = rcu_dereference((pos)->next))
/**
* hlist_del_rcu - deletes entry from hash list without re-initialization
new->next = next;
new->pprev = old->pprev;
- smp_wmb();
+ rcu_assign_pointer(*new->pprev, new);
if (next)
new->next->pprev = &new->next;
- *new->pprev = new;
old->pprev = LIST_POISON2;
}
struct hlist_head *h)
{
struct hlist_node *first = h->first;
+
n->next = first;
n->pprev = &h->first;
- smp_wmb();
+ rcu_assign_pointer(h->first, n);
if (first)
first->pprev = &n->next;
- h->first = n;
}
/**
{
n->pprev = next->pprev;
n->next = next;
- smp_wmb();
+ rcu_assign_pointer(*(n->pprev), n);
next->pprev = &n->next;
- *(n->pprev) = n;
}
/**
{
n->next = prev->next;
n->pprev = &prev->next;
- smp_wmb();
- prev->next = n;
+ rcu_assign_pointer(prev->next, n);
if (n->next)
n->next->pprev = &n->next;
}
* as long as the traversal is guarded by rcu_read_lock().
*/
#define hlist_for_each_entry_rcu(tpos, pos, head, member) \
- for (pos = (head)->first; \
- rcu_dereference(pos) && ({ prefetch(pos->next); 1; }) && \
+ for (pos = rcu_dereference((head)->first); \
+ pos && ({ prefetch(pos->next); 1; }) && \
({ tpos = hlist_entry(pos, typeof(*tpos), member); 1; }); \
- pos = pos->next)
+ pos = rcu_dereference(pos->next))
#endif /* __KERNEL__ */
#endif
projects / mv-sheeva.git / blobdiff