svn commit: r303771 - head/sys/dev/xen/netfront

[Roger Pau Monné]

Author: royger
Date: Fri Aug  5 15:48:56 2016
New Revision: 303771
URL: https://svnweb.freebsd.org/changeset/base/303771

Log:
  xen-netfront: improve the logic when handling nic features from ioctl
  
  Simplify the logic involved in changing the nic features on the fly, and
  only reset the frontend when really needed (when changing RX features). Also
  don't return from the ioctl until the interface has been properly
  reconfigured.
  
  While there, make sure XN_CSUM_FEATURES is used consistently.
  
  Reported by:	julian
  MFC after:	5 days
  X-MFC-with:	r303488
  Sponsored by:	Citrix Systems R&D

Modified:
  head/sys/dev/xen/netfront/netfront.c

Modified: head/sys/dev/xen/netfront/netfront.c
==============================================================================
--- head/sys/dev/xen/netfront/netfront.c	Fri Aug  5 15:32:35 2016	(r303770)
+++ head/sys/dev/xen/netfront/netfront.c	Fri Aug  5 15:48:56 2016	(r303771)
@@ -1760,7 +1760,7 @@ xn_ioctl(struct ifnet *ifp, u_long cmd, 
 #ifdef INET
 	struct ifaddr *ifa = (struct ifaddr *)data;
 #endif
-	int mask, error = 0;
+	int mask, error = 0, reinit;
 
 	dev = sc->xbdev;
 
@@ -1809,41 +1809,36 @@ xn_ioctl(struct ifnet *ifp, u_long cmd, 
 		break;
 	case SIOCSIFCAP:
 		mask = ifr->ifr_reqcap ^ ifp->if_capenable;
+		reinit = 0;
+
 		if (mask & IFCAP_TXCSUM) {
-			if (IFCAP_TXCSUM & ifp->if_capenable) {
-				ifp->if_capenable &= ~(IFCAP_TXCSUM|IFCAP_TSO4);
-				ifp->if_hwassist &= ~(CSUM_TCP | CSUM_UDP
-				    | CSUM_IP | CSUM_TSO);
-			} else {
-				ifp->if_capenable |= IFCAP_TXCSUM;
-				ifp->if_hwassist |= (CSUM_TCP | CSUM_UDP
-				    | CSUM_IP);
-			}
-		}
-		if (mask & IFCAP_RXCSUM) {
-			ifp->if_capenable ^= IFCAP_RXCSUM;
+			ifp->if_capenable ^= IFCAP_TXCSUM;
+			ifp->if_hwassist ^= XN_CSUM_FEATURES;
 		}
 		if (mask & IFCAP_TSO4) {
-			if (IFCAP_TSO4 & ifp->if_capenable) {
-				ifp->if_capenable &= ~IFCAP_TSO4;
-				ifp->if_hwassist &= ~CSUM_TSO;
-			} else if (IFCAP_TXCSUM & ifp->if_capenable) {
-				ifp->if_capenable |= IFCAP_TSO4;
-				ifp->if_hwassist |= CSUM_TSO;
-			} else {
-				IPRINTK("Xen requires tx checksum offload"
-				    " be enabled to use TSO\n");
-				error = EINVAL;
-			}
+			ifp->if_capenable ^= IFCAP_TSO4;
+			ifp->if_hwassist ^= CSUM_TSO;
 		}
-		if (mask & IFCAP_LRO) {
-			ifp->if_capenable ^= IFCAP_LRO;
 
+		if (mask & (IFCAP_RXCSUM | IFCAP_LRO)) {
+			/* These Rx features require us to renegotiate. */
+			reinit = 1;
+
+			if (mask & IFCAP_RXCSUM)
+				ifp->if_capenable ^= IFCAP_RXCSUM;
+			if (mask & IFCAP_LRO)
+				ifp->if_capenable ^= IFCAP_LRO;
 		}
+
+		if (reinit == 0)
+			break;
+
 		/*
 		 * We must reset the interface so the backend picks up the
 		 * new features.
 		 */
+		device_printf(sc->xbdev,
+		    "performing interface reset due to feature change\n");
 		XN_LOCK(sc);
 		netfront_carrier_off(sc);
 		sc->xn_reset = true;
@@ -1865,6 +1860,13 @@ xn_ioctl(struct ifnet *ifp, u_long cmd, 
 		xs_rm(XST_NIL, xenbus_get_node(dev), "feature-gso-tcpv4");
 		xs_rm(XST_NIL, xenbus_get_node(dev), "feature-no-csum-offload");
 		xenbus_set_state(dev, XenbusStateClosing);
+
+		/*
+		 * Wait for the frontend to reconnect before returning
+		 * from the ioctl. 30s should be more than enough for any
+		 * sane backend to reconnect.
+		 */
+		error = tsleep(sc, 0, "xn_rst", 30*hz);
 		break;
 	case SIOCADDMULTI:
 	case SIOCDELMULTI:
@@ -1971,6 +1973,7 @@ xn_connect(struct netfront_info *np)
 	 * packets.
 	 */
 	netfront_carrier_on(np);
+	wakeup(np);
 
 	return (0);
 }
@@ -2085,7 +2088,7 @@ xn_configure_features(struct netfront_in
 #endif
 	if ((ifp->if_capabilities & cap_enabled & IFCAP_TXCSUM) != 0) {
 		ifp->if_capenable |= IFCAP_TXCSUM;
-		ifp->if_hwassist |= CSUM_TCP|CSUM_UDP;
+		ifp->if_hwassist |= XN_CSUM_FEATURES;
 	}
 	if ((ifp->if_capabilities & cap_enabled & IFCAP_RXCSUM) != 0)
 		ifp->if_capenable |= IFCAP_RXCSUM;