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-rw-r--r--mm/list_lru.c29
1 files changed, 12 insertions, 17 deletions
diff --git a/mm/list_lru.c b/mm/list_lru.c
index 1efe4ec..e77c29f 100644
--- a/mm/list_lru.c
+++ b/mm/list_lru.c
@@ -73,19 +73,19 @@ list_lru_walk_node(struct list_lru *lru, int nid, list_lru_walk_cb isolate,
struct list_lru_node *nlru = &lru->node[nid];
struct list_head *item, *n;
unsigned long isolated = 0;
- /*
- * If we don't keep state of at which pass we are, we can loop at
- * LRU_RETRY, since we have no guarantees that the caller will be able
- * to do something other than retry on the next pass. We handle this by
- * allowing at most one retry per object. This should not be altered
- * by any condition other than LRU_RETRY.
- */
- bool first_pass = true;
spin_lock(&nlru->lock);
restart:
list_for_each_safe(item, n, &nlru->list) {
enum lru_status ret;
+
+ /*
+ * decrement nr_to_walk first so that we don't livelock if we
+ * get stuck on large numbesr of LRU_RETRY items
+ */
+ if (--(*nr_to_walk) == 0)
+ break;
+
ret = isolate(item, &nlru->lock, cb_arg);
switch (ret) {
case LRU_REMOVED:
@@ -100,19 +100,14 @@ restart:
case LRU_SKIP:
break;
case LRU_RETRY:
- if (!first_pass) {
- first_pass = true;
- break;
- }
- first_pass = false;
+ /*
+ * The lru lock has been dropped, our list traversal is
+ * now invalid and so we have to restart from scratch.
+ */
goto restart;
default:
BUG();
}
-
- if ((*nr_to_walk)-- == 0)
- break;
-
}
spin_unlock(&nlru->lock);
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