rhashtable: Introduce rhashtable_walk_*
Some existing rhashtable users get too intimate with it by walking
the buckets directly. This prevents us from easily changing the
internals of rhashtable.
This patch adds the helpers rhashtable_walk_init/exit/start/next/stop
which will replace these custom walkers.
They are meant to be usable for both procfs seq_file walks as well
as walking by a netlink dump. The iterator structure should fit
inside a netlink dump cb structure, with at least one element to
spare.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/rhashtable.h b/include/linux/rhashtable.h
index e033784..5885127 100644
--- a/include/linux/rhashtable.h
+++ b/include/linux/rhashtable.h
@@ -18,6 +18,7 @@
#ifndef _LINUX_RHASHTABLE_H
#define _LINUX_RHASHTABLE_H
+#include <linux/compiler.h>
#include <linux/list_nulls.h>
#include <linux/workqueue.h>
#include <linux/mutex.h>
@@ -111,6 +112,7 @@
* @p: Configuration parameters
* @run_work: Deferred worker to expand/shrink asynchronously
* @mutex: Mutex to protect current/future table swapping
+ * @walkers: List of active walkers
* @being_destroyed: True if table is set up for destruction
*/
struct rhashtable {
@@ -121,9 +123,36 @@
struct rhashtable_params p;
struct work_struct run_work;
struct mutex mutex;
+ struct list_head walkers;
bool being_destroyed;
};
+/**
+ * struct rhashtable_walker - Hash table walker
+ * @list: List entry on list of walkers
+ * @resize: Resize event occured
+ */
+struct rhashtable_walker {
+ struct list_head list;
+ bool resize;
+};
+
+/**
+ * struct rhashtable_iter - Hash table iterator, fits into netlink cb
+ * @ht: Table to iterate through
+ * @p: Current pointer
+ * @walker: Associated rhashtable walker
+ * @slot: Current slot
+ * @skip: Number of entries to skip in slot
+ */
+struct rhashtable_iter {
+ struct rhashtable *ht;
+ struct rhash_head *p;
+ struct rhashtable_walker *walker;
+ unsigned int slot;
+ unsigned int skip;
+};
+
static inline unsigned long rht_marker(const struct rhashtable *ht, u32 hash)
{
return NULLS_MARKER(ht->p.nulls_base + hash);
@@ -179,6 +208,12 @@
bool (*compare)(void *, void *),
void *arg);
+int rhashtable_walk_init(struct rhashtable *ht, struct rhashtable_iter *iter);
+void rhashtable_walk_exit(struct rhashtable_iter *iter);
+int rhashtable_walk_start(struct rhashtable_iter *iter) __acquires(RCU);
+void *rhashtable_walk_next(struct rhashtable_iter *iter);
+void rhashtable_walk_stop(struct rhashtable_iter *iter) __releases(RCU);
+
void rhashtable_destroy(struct rhashtable *ht);
#define rht_dereference(p, ht) \