diff mbox series

[4/9] batman-adv: Store modification counter via hash helpers

Message ID 20181030210130.18152-5-sven@narfation.org (mailing list archive)
State Accepted, archived
Commit 59098ad82bbbe8905d29f11c667bccd5c8add621
Delegated to: Simon Wunderlich
Headers
Series batman-adv: Add inconsistent nl dump detection |

Commit Message

Sven Eckelmann Oct. 30, 2018, 9:01 p.m. UTC 
  Multiple datastructures use the hash helper functions to add and remove
entries from the simple hlist based hashes. These are often also dumped to
userspace via netlink and thus should have a generation sequence counter.

Reported-by: Matthias Schiffer <mschiffer@universe-factory.net>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
---
 net/batman-adv/hash.c | 2 ++
 net/batman-adv/hash.h | 6 ++++++
 2 files changed, 8 insertions(+)
diff mbox series

Patch

diff --git a/net/batman-adv/hash.c b/net/batman-adv/hash.c
index 7b49e400..9194f4d8 100644
--- a/net/batman-adv/hash.c
+++ b/net/batman-adv/hash.c
@@ -32,6 +32,8 @@  static void batadv_hash_init(struct batadv_hashtable *hash)
 		INIT_HLIST_HEAD(&hash->table[i]);
 		spin_lock_init(&hash->list_locks[i]);
 	}
+
+	atomic_set(&hash->generation, 0);
 }
 
 /**
diff --git a/net/batman-adv/hash.h b/net/batman-adv/hash.h
index 9490a7ca..0e36fa1c 100644
--- a/net/batman-adv/hash.h
+++ b/net/batman-adv/hash.h
@@ -21,6 +21,7 @@ 
 
 #include "main.h"
 
+#include <linux/atomic.h>
 #include <linux/compiler.h>
 #include <linux/list.h>
 #include <linux/rculist.h>
@@ -58,6 +59,9 @@  struct batadv_hashtable {
 
 	/** @size: size of hashtable */
 	u32 size;
+
+	/** @generation: current (generation) sequence number */
+	atomic_t generation;
 };
 
 /* allocates and clears the hash */
@@ -112,6 +116,7 @@  static inline int batadv_hash_add(struct batadv_hashtable *hash,
 
 	/* no duplicate found in list, add new element */
 	hlist_add_head_rcu(data_node, head);
+	atomic_inc(&hash->generation);
 
 	ret = 0;
 
@@ -154,6 +159,7 @@  static inline void *batadv_hash_remove(struct batadv_hashtable *hash,
 
 		data_save = node;
 		hlist_del_rcu(node);
+		atomic_inc(&hash->generation);
 		break;
 	}
 	spin_unlock_bh(&hash->list_locks[index]);