Module Name: src
Committed By: thorpej
Date: Mon Jan 20 19:35:39 UTC 2020
Modified Files:
src/sys/net: if_media.c
Log Message:
In ifmedia_ioctl(), go to splnet() before acquiring the KERNEL_LOCK.
For non-NET_MPSAFE, this is benign, because we can nest raising to
splnet(). For the NET_MPSAFE, it means that drivers don't need to
raise to splnet() just in order to call ifmedia_ioctl().
To generate a diff of this commit:
cvs rdiff -u -r1.48 -r1.49 src/sys/net/if_media.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/net/if_media.c
diff -u src/sys/net/if_media.c:1.48 src/sys/net/if_media.c:1.49
--- src/sys/net/if_media.c:1.48 Tue Oct 1 17:45:25 2019
+++ src/sys/net/if_media.c Mon Jan 20 19:35:39 2020
@@ -1,4 +1,4 @@
-/* $NetBSD: if_media.c,v 1.48 2019/10/01 17:45:25 chs Exp $ */
+/* $NetBSD: if_media.c,v 1.49 2020/01/20 19:35:39 thorpej Exp $ */
/*-
* Copyright (c) 1998 The NetBSD Foundation, Inc.
@@ -76,7 +76,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: if_media.c,v 1.48 2019/10/01 17:45:25 chs Exp $");
+__KERNEL_RCSID(0, "$NetBSD: if_media.c,v 1.49 2020/01/20 19:35:39 thorpej Exp $");
#include <sys/param.h>
#include <sys/systm.h>
@@ -362,12 +362,21 @@ ifmedia_ioctl(struct ifnet *ifp, struct
int e;
/*
- * If if_is_mpsafe(ifp), KERNEL_LOCK isn't held here,
- * but ifmedia_ioctl_locked isn't MP-safe yet, so we must hold the lock.
+ * If if_is_mpsafe(ifp), KERNEL_LOCK isn't held here and
+ * ipl will not have been raised (well, maybe it has, but
+ * it doesn't matter), but ifmedia_ioctl_locked isn't MP-safe
+ * yet, so we go to splnet and grab the KERNEL_LOCK.
+ *
+ * In the non-mpsafe case, the interface's ioctl routine
+ * will already be running at splnet() and so raising it
+ * again is redundant, but also harmless.
*/
+ int s = splnet();
KERNEL_LOCK_IF_IFP_MPSAFE(ifp);
e = ifmedia_ioctl_locked(ifp, ifr, ifm, cmd);
KERNEL_UNLOCK_IF_IFP_MPSAFE(ifp);
+ splx(s);
+
return e;
}
