Merge branch 'for-3.1' of git://linux-nfs.org/~bfields/linux

[cascardo/linux.git] / include / net / netlink.h

diff --git a/include/net/netlink.h b/include/net/netlink.h
index 02740a9..98c1854 100644 (file)
--- a/include/net/netlink.h
+++ b/include/net/netlink.h
@@ -638,6 +638,30 @@ static inline int nlmsg_unicast(struct sock *sk, struct sk_buff *skb, u32 pid)
             nlmsg_ok(pos, rem); \
             pos = nlmsg_next(pos, &(rem)))
 
+/**
+ * nl_dump_check_consistent - check if sequence is consistent and advertise if not
+ * @cb: netlink callback structure that stores the sequence number
+ * @nlh: netlink message header to write the flag to
+ *
+ * This function checks if the sequence (generation) number changed during dump
+ * and if it did, advertises it in the netlink message header.
+ *
+ * The correct way to use it is to set cb->seq to the generation counter when
+ * all locks for dumping have been acquired, and then call this function for
+ * each message that is generated.
+ *
+ * Note that due to initialisation concerns, 0 is an invalid sequence number
+ * and must not be used by code that uses this functionality.
+ */
+static inline void
+nl_dump_check_consistent(struct netlink_callback *cb,
+                        struct nlmsghdr *nlh)
+{
+       if (cb->prev_seq && cb->seq != cb->prev_seq)
+               nlh->nlmsg_flags |= NLM_F_DUMP_INTR;
+       cb->prev_seq = cb->seq;
+}
+
 /**************************************************************************
  * Netlink Attributes
  **************************************************************************/