De-virtualize V_pf_mtag_z to eliminate kernel panics.

[Craig Rodrigues]

Gleb,

Since you did a lot of work in GRN 240233
to fix PF issues, especially for VIMAGE, I thought I would
ask your opinion on the attached patch.

In this post:

http://lists.freebsd.org/pipermail/freebsd-virtualization/2013-July/001405.html

I reported multiple PF-related panics when VIMAGE was enabled
in my kernel config.

In these posts:
http://lists.freebsd.org/pipermail/freebsd-virtualization/2013-July/001413.html
http://lists.freebsd.org/pipermail/freebsd-virtualization/2013-July/001420.html

Marko Zec seemed to think that de-virtualizing V_pf_mtag_z
would be a valid solution to this problem, and that keeping
V_pf_mtag_z as a per-vnet variable is not necessary.

What do you think of Marko's comments, and this patch?

Thanks.
--
Craig
-------------- next part --------------
Index: sys/netpfil/pf/pf.c
===================================================================
--- sys/netpfil/pf/pf.c	(revision 253346)
+++ sys/netpfil/pf/pf.c	(working copy)
@@ -187,8 +187,7 @@
 
 static VNET_DEFINE(uma_zone_t,	pf_sources_z);
 #define	V_pf_sources_z	VNET(pf_sources_z)
-static VNET_DEFINE(uma_zone_t,	pf_mtag_z);
-#define	V_pf_mtag_z	VNET(pf_mtag_z)
+uma_zone_t pf_mtag_z;
 VNET_DEFINE(uma_zone_t,	 pf_state_z);
 VNET_DEFINE(uma_zone_t,	 pf_state_key_z);
 
@@ -749,7 +748,7 @@
 	V_pf_altqs_inactive = &V_pf_altqs[1];
 
 	/* Mbuf tags */
-	V_pf_mtag_z = uma_zcreate("pf mtags", sizeof(struct m_tag) +
+	pf_mtag_z = uma_zcreate("pf mtags", sizeof(struct m_tag) +
 	    sizeof(struct pf_mtag), NULL, NULL, pf_mtag_init, NULL,
 	    UMA_ALIGN_PTR, 0);
 
@@ -803,7 +802,7 @@
 	mtx_destroy(&pf_overloadqueue_mtx);
 	mtx_destroy(&pf_unlnkdrules_mtx);
 
-	uma_zdestroy(V_pf_mtag_z);
+	uma_zdestroy(pf_mtag_z);
 	uma_zdestroy(V_pf_sources_z);
 	uma_zdestroy(V_pf_state_z);
 	uma_zdestroy(V_pf_state_key_z);
@@ -827,7 +826,7 @@
 pf_mtag_free(struct m_tag *t)
 {
 
-	uma_zfree(V_pf_mtag_z, t);
+	uma_zfree(pf_mtag_z, t);
 }
 
 struct pf_mtag *
@@ -838,7 +837,7 @@
 	if ((mtag = m_tag_find(m, PACKET_TAG_PF, NULL)) != NULL)
 		return ((struct pf_mtag *)(mtag + 1));
 
-	mtag = uma_zalloc(V_pf_mtag_z, M_NOWAIT);
+	mtag = uma_zalloc(pf_mtag_z, M_NOWAIT);
 	if (mtag == NULL)
 		return (NULL);
 	bzero(mtag + 1, sizeof(struct pf_mtag));