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 This check has now now been
replaced by checking if "M_HASHTYPE_GET(m)" is different from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, 3 insertions, 2 deletions

diff --git a/sys/net/netisr.c b/sys/net/netisr.c
index 049bbf1..178c3cb 100644
--- a/sys/net/netisr.c
+++ b/sys/net/netisr.c
@@ -682,12 +682,13 @@ netisr_select_cpuid(struct netisr_proto *npp, u_int dispatch_policy,
 	}
 
 	if (policy == NETISR_POLICY_FLOW) {
-		if (!(m->m_flags & M_FLOWID) && npp->np_m2flow != NULL) {
+		if (M_HASHTYPE_GET(m) == M_HASHTYPE_NONE &&
+		    npp->np_m2flow != NULL) {
 			m = npp->np_m2flow(m, source);
 			if (m == NULL)
 				return (NULL);
 		}
-		if (m->m_flags & M_FLOWID) {
+		if (M_HASHTYPE_GET(m) != M_HASHTYPE_NONE) {
 			*cpuidp =
 			    netisr_default_flow2cpu(m->m_pkthdr.flowid);
 			return (m);