Module Name: src
Committed By: ozaki-r
Date: Tue Feb 7 02:36:48 UTC 2017
Modified Files:
src/sys/sys: mbuf.h
Log Message:
Tweak m_get_rcvif
Call pserialize_read_exit if if_byindex returns NULL in m_get_rcvif.
By changing so, callers need to call m_put_rcvif only if m_get_rcvif
returns non-NULL.
Old m_get_rcvif/m_put_rcvif could forget to call pserialize_read_exit,
which is pointed out by maxv@. The change fixes it.
To generate a diff of this commit:
cvs rdiff -u -r1.167 -r1.168 src/sys/sys/mbuf.h
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/sys/mbuf.h
diff -u src/sys/sys/mbuf.h:1.167 src/sys/sys/mbuf.h:1.168
--- src/sys/sys/mbuf.h:1.167 Tue Oct 4 14:13:21 2016
+++ src/sys/sys/mbuf.h Tue Feb 7 02:36:48 2017
@@ -1,4 +1,4 @@
-/* $NetBSD: mbuf.h,v 1.167 2016/10/04 14:13:21 christos Exp $ */
+/* $NetBSD: mbuf.h,v 1.168 2017/02/07 02:36:48 ozaki-r Exp $ */
/*-
* Copyright (c) 1996, 1997, 1999, 2001, 2007 The NetBSD Foundation, Inc.
@@ -1006,16 +1006,24 @@ void m_print(const struct mbuf *, const
/*
* Get rcvif of a mbuf.
*
- * The caller must call m_put_rcvif after using rcvif. The caller cannot
- * block or sleep during using rcvif. Insofar as the constraint is satisfied,
- * the API ensures a got rcvif isn't be freed until m_put_rcvif is called.
+ * The caller must call m_put_rcvif after using rcvif if the returned rcvif
+ * isn't NULL. If the returned rcvif is NULL, the caller doesn't need to call
+ * m_put_rcvif (although calling it is safe).
+ *
+ * The caller must not block or sleep while using rcvif. The API ensures a
+ * returned rcvif isn't freed until m_put_rcvif is called.
*/
static __inline struct ifnet *
m_get_rcvif(const struct mbuf *m, int *s)
{
+ struct ifnet *ifp;
*s = pserialize_read_enter();
- return if_byindex(m->m_pkthdr.rcvif_index);
+ ifp = if_byindex(m->m_pkthdr.rcvif_index);
+ if (__predict_false(ifp == NULL))
+ pserialize_read_exit(*s);
+
+ return ifp;
}
static __inline void
