svn commit: r349532 - head/sys/net

[John Baldwin]

Author: jhb
Date: Sat Jun 29 00:51:38 2019
New Revision: 349532
URL: https://svnweb.freebsd.org/changeset/base/349532

Log:
  Support IFCAP_NOMAP in vlan(4).
  
  Enable IFCAP_NOMAP for a vlan interface if it is supported by the
  underlying trunk device.
  
  Reviewed by:	gallatin, hselasky, rrs
  Sponsored by:	Netflix
  Differential Revision:	https://reviews.freebsd.org/D20616

Modified:
  head/sys/net/if_vlan.c

Modified: head/sys/net/if_vlan.c
==============================================================================
--- head/sys/net/if_vlan.c	Sat Jun 29 00:50:25 2019	(r349531)
+++ head/sys/net/if_vlan.c	Sat Jun 29 00:51:38 2019	(r349532)
@@ -1731,6 +1731,16 @@ vlan_capabilities(struct ifvlan *ifv)
 	ena |= (mena & IFCAP_TXRTLMT);
 #endif
 
+	/*
+	 * If the parent interface supports unmapped mbufs, so does
+	 * the VLAN interface.  Note that this should be fine even for
+	 * interfaces that don't support hardware tagging as headers
+	 * are prepended in normal mbufs to unmapped mbufs holding
+	 * payload data.
+	 */
+	cap |= (p->if_capabilities & IFCAP_NOMAP);
+	ena |= (mena & IFCAP_NOMAP);
+
 	ifp->if_capabilities = cap;
 	ifp->if_capenable = ena;
 	ifp->if_hwassist = hwa;