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Diffstat (limited to 'fs/btrfs/ulist.c')
-rw-r--r--fs/btrfs/ulist.c34
1 files changed, 18 insertions, 16 deletions
diff --git a/fs/btrfs/ulist.c b/fs/btrfs/ulist.c
index ad993bc2df93..ab942f46b3dd 100644
--- a/fs/btrfs/ulist.c
+++ b/fs/btrfs/ulist.c
@@ -23,9 +23,9 @@
*
* ulist = ulist_alloc();
* ulist_add(ulist, root);
- * elem = NULL;
+ * ULIST_ITER_INIT(&uiter);
*
- * while ((elem = ulist_next(ulist, elem)) {
+ * while ((elem = ulist_next(ulist, &uiter)) {
* for (all child nodes n in elem)
* ulist_add(ulist, n);
* do something useful with the node;
@@ -146,11 +146,20 @@ EXPORT_SYMBOL(ulist_free);
int ulist_add(struct ulist *ulist, u64 val, unsigned long aux,
gfp_t gfp_mask)
{
+ return ulist_add_merge(ulist, val, aux, NULL, gfp_mask);
+}
+
+int ulist_add_merge(struct ulist *ulist, u64 val, unsigned long aux,
+ unsigned long *old_aux, gfp_t gfp_mask)
+{
int i;
for (i = 0; i < ulist->nnodes; ++i) {
- if (ulist->nodes[i].val == val)
+ if (ulist->nodes[i].val == val) {
+ if (old_aux)
+ *old_aux = ulist->nodes[i].aux;
return 0;
+ }
}
if (ulist->nnodes >= ulist->nodes_alloced) {
@@ -188,33 +197,26 @@ EXPORT_SYMBOL(ulist_add);
/**
* ulist_next - iterate ulist
* @ulist: ulist to iterate
- * @prev: previously returned element or %NULL to start iteration
+ * @uiter: iterator variable, initialized with ULIST_ITER_INIT(&iterator)
*
* Note: locking must be provided by the caller. In case of rwlocks only read
* locking is needed
*
- * This function is used to iterate an ulist. The iteration is started with
- * @prev = %NULL. It returns the next element from the ulist or %NULL when the
+ * This function is used to iterate an ulist.
+ * It returns the next element from the ulist or %NULL when the
* end is reached. No guarantee is made with respect to the order in which
* the elements are returned. They might neither be returned in order of
* addition nor in ascending order.
* It is allowed to call ulist_add during an enumeration. Newly added items
* are guaranteed to show up in the running enumeration.
*/
-struct ulist_node *ulist_next(struct ulist *ulist, struct ulist_node *prev)
+struct ulist_node *ulist_next(struct ulist *ulist, struct ulist_iterator *uiter)
{
- int next;
-
if (ulist->nnodes == 0)
return NULL;
-
- if (!prev)
- return &ulist->nodes[0];
-
- next = (prev - ulist->nodes) + 1;
- if (next < 0 || next >= ulist->nnodes)
+ if (uiter->i < 0 || uiter->i >= ulist->nnodes)
return NULL;
- return &ulist->nodes[next];
+ return &ulist->nodes[uiter->i++];
}
EXPORT_SYMBOL(ulist_next);