Add a new function to do a CPU ID lookup based on RSS hash information.

This is intended to be used by various places that wish to hash some
information about a TCP/UDP/IP flow but don't necessarily have a
live mbuf to do it with.

Refactor rss_m2cpuid() to use the refactored function.

1 files changed, 18 insertions, 11 deletions

diff --git a/sys/netinet/in_rss.c b/sys/netinet/in_rss.c
index 79da70d..a95f0c3 100644
--- a/sys/netinet/in_rss.c
+++ b/sys/netinet/in_rss.c
@@ -407,27 +407,34 @@ rss_getcpu(u_int bucket)
 }
 
 /*
- * netisr CPU affinity lookup routine for use by protocols.
+ * netisr CPU affinity lookup given just the hash and hashtype.
  */
-struct mbuf *
-rss_m2cpuid(struct mbuf *m, uintptr_t source, u_int *cpuid)
+u_int
+rss_hash2cpuid(uint32_t hash_val, uint32_t hash_type)
 {
 
-	M_ASSERTPKTHDR(m);
-
-	switch (M_HASHTYPE_GET(m)) {
+	switch (hash_type) {
 	case M_HASHTYPE_RSS_IPV4:
 	case M_HASHTYPE_RSS_TCP_IPV4:
-		*cpuid = rss_getcpu(rss_getbucket(m->m_pkthdr.flowid));
-		return (m);
-
+		return (rss_getcpu(rss_getbucket(hash_val)));
 	default:
-		*cpuid = NETISR_CPUID_NONE;
-		return (m);
+		return (NETISR_CPUID_NONE);
 	}
 }
 
 /*
+ * netisr CPU affinity lookup routine for use by protocols.
+ */
+struct mbuf *
+rss_m2cpuid(struct mbuf *m, uintptr_t source, u_int *cpuid)
+{
+
+	M_ASSERTPKTHDR(m);
+	*cpuid = rss_hash2cpuid(m->m_pkthdr.flowid, M_HASHTYPE_GET(m));
+	return (m);
+}
+
+/*
  * Query the RSS hash algorithm.
  */
 u_int