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change the netmap mbuf destructor so the same code works also on FreeBSD 9.

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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.
This commit is contained in:
Luigi Rizzo 2014-06-10 16:06:59 +00:00
parent fdbd636433
commit 63a3395e5d
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=267328
1 changed files with 16 additions and 9 deletions
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25
sys/dev/netmap/netmap_generic.c
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@ -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);