From f9ef96ca7179b80ae61f9ff76c2f0e49c58345eb Mon Sep 17 00:00:00 2001
From: Robert Watson <rwatson@FreeBSD.org>
Date: Fri, 26 Jun 2009 00:36:47 +0000
Subject: [PATCH] Define four wrapper functions for interface address locking,
 if_addr_rlock() and if_addr_runlock() for regular address lists, and
 if_maddr_rlock() and if_maddr_runlock() for multicast address lists.

We will use these in various kernel modules to avoid encoding specific
type and locking strategy information into modules that currently use
IF_ADDR_LOCK() and IF_ADDR_UNLOCK() directly.

MFC after:	6 weeks
---
 sys/net/if.c     | 34 ++++++++++++++++++++++++++++++++++
 sys/net/if_var.h | 10 ++++++++++
 2 files changed, 44 insertions(+)

diff --git a/sys/net/if.c b/sys/net/if.c
index 58ab6792cf8f..c41390a07497 100644
--- a/sys/net/if.c
+++ b/sys/net/if.c
@@ -1418,6 +1418,40 @@ if_rtdel(struct radix_node *rn, void *arg)
 	return (0);
 }
 
+/*
+ * Wrapper functions for struct ifnet address list locking macros.  These are
+ * used by kernel modules to avoid encoding programming interface or binary
+ * interface assumptions that may be violated when kernel-internal locking
+ * approaches change.
+ */
+void
+if_addr_rlock(struct ifnet *ifp)
+{
+
+	IF_ADDR_LOCK(ifp);
+}
+
+void
+if_addr_runlock(struct ifnet *ifp)
+{
+
+	IF_ADDR_UNLOCK(ifp);
+}
+
+void
+if_maddr_rlock(struct ifnet *ifp)
+{
+
+	IF_ADDR_LOCK(ifp);
+}
+
+void
+if_maddr_runlock(struct ifnet *ifp)
+{
+
+	IF_ADDR_UNLOCK(ifp);
+}
+
 /*
  * Reference count functions for ifaddrs.
  */
diff --git a/sys/net/if_var.h b/sys/net/if_var.h
index 35e4232b0a50..df09035f0d7d 100644
--- a/sys/net/if_var.h
+++ b/sys/net/if_var.h
@@ -252,6 +252,16 @@ typedef void if_init_f_t(void *);
 #define	IF_ADDR_UNLOCK(if)	mtx_unlock(&(if)->if_addr_mtx)
 #define	IF_ADDR_LOCK_ASSERT(if)	mtx_assert(&(if)->if_addr_mtx, MA_OWNED)
 
+/*
+ * Function variations on locking macros intended to be used by loadable
+ * kernel modules in order to divorce them from the internals of address list
+ * locking.
+ */
+void	if_addr_rlock(struct ifnet *ifp);	/* if_addrhead */
+void	if_addr_runlock(struct ifnet *ifp);	/* if_addrhead */
+void	if_maddr_rlock(struct ifnet *ifp);	/* if_multiaddrs */
+void	if_maddr_runlock(struct ifnet *ifp);	/* if_multiaddrs */
+
 /*
  * Output queues (ifp->if_snd) and slow device input queues (*ifp->if_slowq)
  * are queues of messages stored on ifqueue structures