[ovs-dev] [patch_v6] dp-packet: Reset DPDK hwol flags on init.

[Darrell Ball]

Reset the DPDK hwol flags in dp_packet_init_.  The new hwol bad checksum
flag is uninitialized for non-dpdk ports and this is noticed as test
failures using netdev-dummy ports, when built with the --with-dpdk
flag set. Hence, in this case, packets may be falsely marked as having a
bad checksum. The existing APIs are simplified at the same time by
making them specific to either DPDK or otherwise; they also now
manage a single field.

Reported-at: https://mail.openvswitch.org/pipermail/ovs-discuss/2017-August/045081.html
Fixes: 7451af618e0d ("dp-packet : Update DPDK rx checksum validation functions.")
CC: Sugesh Chandran <sugesh.chandran at intel.com>
Signed-off-by: Darrell Ball <dlu998 at gmail.com>
---

v5->v6: Refactor some existing apis and incorporate
        review comments.

v3->v5: Update the commit message with more context.

v2->v3: Use existed API to reset both the DPDK HWOL flags.

v1->v2: Fix build failure for without --with-dpdk.

 lib/dp-packet.c   |  1 +
 lib/dp-packet.h   | 24 +++++++++++++++++++++---
 lib/netdev-dpdk.c |  2 +-
 3 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/lib/dp-packet.c b/lib/dp-packet.c
index 67aa406..c1f43f3 100644
--- a/lib/dp-packet.c
+++ b/lib/dp-packet.c
@@ -31,6 +31,7 @@ dp_packet_init__(struct dp_packet *b, size_t allocated, enum dp_packet_source so
     dp_packet_reset_offsets(b);
     pkt_metadata_init(&b->md, 0);
     dp_packet_rss_invalidate(b);
+    dp_packet_mbuf_init(b);
     dp_packet_reset_cutlen(b);
     /* By default assume the packet type to be Ethernet. */
     b->packet_type = htonl(PT_ETH);
diff --git a/lib/dp-packet.h b/lib/dp-packet.h
index 8f52fee..bb3f9db 100644
--- a/lib/dp-packet.h
+++ b/lib/dp-packet.h
@@ -605,12 +605,30 @@ dp_packet_rss_valid(struct dp_packet *p)
 }
 
 static inline void
-dp_packet_rss_invalidate(struct dp_packet *p)
+dp_packet_rss_invalidate(struct dp_packet *p OVS_UNUSED)
+{
+#ifndef DPDK_NETDEV
+    p->rss_hash_valid = false;
+#endif
+}
+
+static inline void
+dp_packet_mbuf_rss_flag_reset(struct dp_packet *p OVS_UNUSED)
 {
 #ifdef DPDK_NETDEV
     p->mbuf.ol_flags &= ~PKT_RX_RSS_HASH;
-#else
-    p->rss_hash_valid = false;
+#endif
+}
+
+/* This initialization is needed for packets that do not come
+ * from DPDK interfaces, when vswitchd is built with --with-dpdk.
+ * The DPDK rte library will still otherwise manage the mbuf.
+ * We only need to initialize the mbuf ol_flags. */
+static inline void
+dp_packet_mbuf_init(struct dp_packet *p OVS_UNUSED)
+{
+#ifdef DPDK_NETDEV
+    p->mbuf.ol_flags = 0;
 #endif
 }
 
diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c
index 1d82bca..9fd98af 100644
--- a/lib/netdev-dpdk.c
+++ b/lib/netdev-dpdk.c
@@ -2916,7 +2916,7 @@ netdev_dpdk_ring_send(struct netdev *netdev, int qid,
      * modified by the consumer of the ring and return into the datapath
      * without recalculating the RSS hash. */
     for (i = 0; i < batch->count; i++) {
-        dp_packet_rss_invalidate(batch->packets[i]);
+        dp_packet_mbuf_rss_flag_reset(batch->packets[i]);
     }
 
     netdev_dpdk_send__(dev, qid, batch, may_steal, concurrent_txq);
-- 
1.9.1