Start process of removing the use of the deprecated "M_FLOWID" flag

from the FreeBSD network code. The flag is still kept around in the
"sys/mbuf.h" header file, but does no longer have any users. Instead
the "m_pkthdr.rsstype" field in the mbuf structure is now used to
decide the meaning of the "m_pkthdr.flowid" field. To modify the
"m_pkthdr.rsstype" field please use the existing "M_HASHTYPE_XXX"
macros as defined in the "sys/mbuf.h" header file.

This patch introduces new behaviour in the transmit direction.
Previously network drivers checked if "M_FLOWID" was set in "m_flags"
before using the "m_pkthdr.flowid" field. This check has now now been
replaced by checking if "M_HASHTYPE_GET(m)" is different from
"M_HASHTYPE_NONE". In the future more hashtypes will be added, for
example hashtypes for hardware dedicated flows.

"M_HASHTYPE_OPAQUE" indicates that the "m_pkthdr.flowid" value is
valid and has no particular type. This change removes the need for an
"if" statement in TCP transmit code checking for the presence of a
valid flowid value. The "if" statement mentioned above is now a direct
variable assignment which is then later checked by the respective
network drivers like before.

Additional notes:
- The SCTP code changes will be committed as a separate patch.
- Removal of the "M_FLOWID" flag will also be done separately.
- The FreeBSD version has been bumped.

MFC after:	1 month
Sponsored by:	Mellanox Technologies

1 files changed, 2 insertions, 2 deletions

diff --git a/sys/dev/netmap/netmap_freebsd.c b/sys/dev/netmap/netmap_freebsd.c
index 322670814553..dd968ca51577 100644
--- a/sys/dev/netmap/netmap_freebsd.c
+++ b/sys/dev/netmap/netmap_freebsd.c
@@ -204,7 +204,7 @@ netmap_catch_tx(struct netmap_generic_adapter *gna, int enable)
  * of the transmission does not consume resources.
  *
  * On FreeBSD, and on multiqueue cards, we can force the queue using
- *      if ((m->m_flags & M_FLOWID) != 0)
+ *      if (M_HASHTYPE_GET(m) != M_HASHTYPE_NONE)
  *              i = m->m_pkthdr.flowid % adapter->num_queues;
  *      else
  *              i = curcpu % adapter->num_queues;
@@ -240,7 +240,7 @@ generic_xmit_frame(struct ifnet *ifp, struct mbuf *m,
 	m->m_len = m->m_pkthdr.len = len;
 	// inc refcount. All ours, we could skip the atomic
 	atomic_fetchadd_int(PNT_MBUF_REFCNT(m), 1);
-	m->m_flags |= M_FLOWID;
+	M_HASHTYPE_SET(m, M_HASHTYPE_OPAQUE);
 	m->m_pkthdr.flowid = ring_nr;
 	m->m_pkthdr.rcvif = ifp; /* used for tx notification */
 	ret = NA(ifp)->if_transmit(ifp, m);