Author: luigi
Date: Tue Jun 10 16:06:59 2014
New Revision: 267328
URL: http://svnweb.freebsd.org/changeset/base/267328
Log:
change the netmap mbuf destructor so the same code works also on FreeBSD 9.
For head and 10 this change has no effect, but on stable/9 it would cause
panics when using emulated netmap on top of a standard device driver.
Modified:
head/sys/dev/netmap/netmap_generic.c
Modified: head/sys/dev/netmap/netmap_generic.c
==============================================================================
--- head/sys/dev/netmap/netmap_generic.c Tue Jun 10 15:20:41 2014
(r267327)
+++ head/sys/dev/netmap/netmap_generic.c Tue Jun 10 16:06:59 2014
(r267328)
@@ -102,24 +102,30 @@ __FBSDID("$FreeBSD$");
* mbuf wrappers
*/
-/* mbuf destructor, also need to change the type to EXT_EXTREF,
+/*
+ * mbuf destructor, also need to change the type to EXT_EXTREF,
* add an M_NOFREE flag, and then clear the flag and
* chain into uma_zfree(zone_pack, mf)
* (or reinstall the buffer ?)
+ *
+ * On FreeBSD 9 the destructor is called as ext_free(ext_arg1, ext_arg2)
+ * whereas newer version have ext_free(m, ext_arg1, ext_arg2)
+ * For compatibility we set ext_arg1 = m on allocation so we have
+ * the same code on both.
*/
#define SET_MBUF_DESTRUCTOR(m, fn) do { \
- (m)->m_ext.ext_free = (void *)fn; \
- (m)->m_ext.ext_type = EXT_EXTREF; \
-} while (0)
+ (m)->m_ext.ext_free = (void *)fn; \
+ (m)->m_ext.ext_type = EXT_EXTREF; \
+ } while (0)
static void
-netmap_default_mbuf_destructor(struct mbuf *m)
+netmap_default_mbuf_destructor(struct mbuf *m)
{
- /* restore original mbuf */
- m->m_ext.ext_buf = m->m_data = m->m_ext.ext_arg1;
- m->m_ext.ext_arg1 = NULL;
+ /* restore original data pointer and type */
+ m->m_ext.ext_buf = m->m_data = m->m_ext.ext_arg2;
m->m_ext.ext_type = EXT_PACKET;
m->m_ext.ext_free = NULL;
+ m->m_ext.ext_arg1 = m->m_ext.ext_arg2 = NULL;
if (*(m->m_ext.ref_cnt) == 0)
*(m->m_ext.ref_cnt) = 1;
uma_zfree(zone_pack, m);
@@ -131,7 +137,8 @@ netmap_get_mbuf(int len)
struct mbuf *m;
m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR | M_NOFREE);
if (m) {
- m->m_ext.ext_arg1 = m->m_ext.ext_buf; // XXX save
+ m->m_ext.ext_arg1 = m; /* FreeBSD 9 compat */
+ m->m_ext.ext_arg2 = m->m_ext.ext_buf; /* save original */
m->m_ext.ext_free = (void *)netmap_default_mbuf_destructor;
m->m_ext.ext_type = EXT_EXTREF;
ND(5, "create m %p refcnt %d", m, *m->m_ext.ref_cnt);
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