diff mbox series

[ovs-dev,v2,2/2] userspace: Add Generic Segmentation Offloading.

Message ID 20230621184532.535492-2-mkp@redhat.com
State Superseded, archived
Headers show
Series [ovs-dev,v2,1/2] userspace: Respect tso/gso segment size. | expand

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Commit Message

Mike Pattrick June 21, 2023, 6:45 p.m. UTC
From: Flavio Leitner <fbl@sysclose.org>

This provides a software implementation in the case
the egress netdev doesn't support segmentation in hardware.

The challenge here is to guarantee packet ordering in the
original batch that may be full of TSO packets. Each TSO
packet can go up to ~64kB, so with segment size of 1440
that means about 44 packets for each TSO. Each batch has
32 packets, so the total batch amounts to 1408 normal
packets.

The segmentation estimates the total number of packets
and then the total number of batches. Then allocate
enough memory and finally do the work.

Finally each batch is sent in order to the netdev.

Signed-off-by: Flavio Leitner <fbl@sysclose.org>
Co-authored-by: Mike Pattrick <mkp@redhat.com>
Signed-off-by: Mike Pattrick <mkp@redhat.com>
---
 lib/automake.mk     |   2 +
 lib/dp-packet-gso.c | 172 ++++++++++++++++++++++++++++++++++++++++++++
 lib/dp-packet-gso.h |  24 +++++++
 lib/dp-packet.h     |  11 +++
 lib/netdev-dpdk.c   |  46 ++++++++----
 lib/netdev-linux.c  |  58 ---------------
 lib/netdev.c        | 120 ++++++++++++++++++-------------
 lib/packets.c       |   4 +-
 8 files changed, 314 insertions(+), 123 deletions(-)
 create mode 100644 lib/dp-packet-gso.c
 create mode 100644 lib/dp-packet-gso.h
diff mbox series

Patch

diff --git a/lib/automake.mk b/lib/automake.mk
index e64ee76ce..49a92958d 100644
--- a/lib/automake.mk
+++ b/lib/automake.mk
@@ -118,6 +118,8 @@  lib_libopenvswitch_la_SOURCES = \
 	lib/dpctl.h \
 	lib/dp-packet.h \
 	lib/dp-packet.c \
+	lib/dp-packet-gso.c \
+	lib/dp-packet-gso.h \
 	lib/dpdk.h \
 	lib/dpif-netdev-extract-study.c \
 	lib/dpif-netdev-lookup.h \
diff --git a/lib/dp-packet-gso.c b/lib/dp-packet-gso.c
new file mode 100644
index 000000000..bc72e2f90
--- /dev/null
+++ b/lib/dp-packet-gso.c
@@ -0,0 +1,172 @@ 
+/*
+ * Copyright (c) 2021 Red Hat, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <config.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "coverage.h"
+#include "dp-packet.h"
+#include "dp-packet-gso.h"
+#include "netdev-provider.h"
+#include "openvswitch/vlog.h"
+
+VLOG_DEFINE_THIS_MODULE(dp_packet_gso);
+
+COVERAGE_DEFINE(soft_seg_good);
+
+/* Retuns a new packet that is a segment of packet 'p'.
+ *
+ * The new packet is initialized with 'hdr_len' bytes from the
+ * start of packet 'p' and then appended with 'data_len' bytes
+ * from the 'data' buffer.
+ *
+ * Note: The packet headers are not updated. */
+static struct dp_packet *
+dp_packet_gso_seg_new(const struct dp_packet *p, size_t hdr_len,
+                      const char *data, size_t data_len)
+{
+    struct dp_packet *seg = dp_packet_new_with_headroom(hdr_len + data_len,
+                                                        dp_packet_headroom(p));
+
+    /* Append the original packet headers and then the payload. */
+    dp_packet_put(seg, dp_packet_data(p), hdr_len);
+    dp_packet_put(seg, data, data_len);
+
+    /* The new segment should have the same offsets. */
+    seg->l2_5_ofs = p->l2_5_ofs;
+    seg->l3_ofs = p->l3_ofs;
+    seg->l4_ofs = p->l4_ofs;
+
+    /* The protocol headers remain the same, so preserve hash and mark. */
+    *dp_packet_rss_ptr(seg) = dp_packet_get_rss_hash(p);
+    *dp_packet_flow_mark_ptr(seg) = *dp_packet_flow_mark_ptr(p);
+
+    /* The segment should inherit all the offloading flags from the
+     * original packet, except for the TCP segmentation, external
+     * buffer and indirect buffer flags. */
+    *dp_packet_ol_flags_ptr(seg) = *dp_packet_ol_flags_ptr(p)
+        & ~(DP_PACKET_OL_TX_TCP_SEG | DP_PACKET_OL_EXTERNAL
+            | DP_PACKET_OL_INDIRECT);
+
+    dp_packet_hwol_reset_tcp_seg(seg);
+
+    return seg;
+}
+
+/* Returns the calculated number of TCP segments in packet 'p'. */
+int
+dp_packet_gso_nr_segs(struct dp_packet *p)
+{
+    uint16_t segsz = dp_packet_get_tso_segsz(p);
+    const char *data_tail;
+    const char *data_pos;
+    int n_segs;
+
+    data_pos = dp_packet_get_tcp_payload(p);
+    data_tail = (char *) dp_packet_tail(p) - dp_packet_l2_pad_size(p);
+    data_pos = dp_packet_get_tcp_payload(p);
+    n_segs = DIV_ROUND_UP((data_tail - data_pos), segsz);
+
+    return n_segs;
+
+}
+
+/* Perform software segmentation on packet 'p'.
+ *
+ * Returns all the segments added to the array of preallocated
+ * batches in 'batches' starting at batch position 'batch_pos'. */
+void
+dp_packet_gso(struct dp_packet *p, struct dp_packet_batch *batches,
+              size_t *batch_pos)
+{
+    struct tcp_header *tcp_hdr;
+    struct ip_header *ip_hdr;
+    struct dp_packet *seg;
+    uint16_t tcp_offset;
+    uint16_t tso_segsz;
+    uint32_t tcp_seq;
+    uint16_t ip_id;
+    int hdr_len;
+
+    tso_segsz = dp_packet_get_tso_segsz(p);
+    if (!tso_segsz) {
+        VLOG_WARN("GSO packet with len %d with no segment size.",
+                  dp_packet_size(p));
+        return;
+    }
+
+    tcp_hdr = dp_packet_l4(p);
+    tcp_offset = TCP_OFFSET(tcp_hdr->tcp_ctl);
+    tcp_seq = ntohl(get_16aligned_be32(&tcp_hdr->tcp_seq));
+    hdr_len = ((char *) dp_packet_l4(p) - (char *) dp_packet_eth(p))
+              + tcp_offset * 4;
+    ip_id = 0;
+    if (dp_packet_hwol_is_ipv4(p)) {
+        ip_hdr = dp_packet_l3(p);
+        ip_id = ntohs(ip_hdr->ip_id);
+    }
+
+    const char *data_tail = (char *) dp_packet_tail(p)
+                            - dp_packet_l2_pad_size(p);
+    const char *data_pos = dp_packet_get_tcp_payload(p);
+    int n_segs = dp_packet_gso_nr_segs(p);
+    int seg_len;
+    for (int i = 0; i < n_segs; i++) {
+        seg_len = data_tail - data_pos;
+        if (seg_len > tso_segsz) {
+            seg_len = tso_segsz;
+        }
+
+        seg = dp_packet_gso_seg_new(p, hdr_len, data_pos, seg_len);
+        data_pos += seg_len;
+
+        /* Update L3 header. */
+        if (dp_packet_hwol_is_ipv4(seg)) {
+            ip_hdr = dp_packet_l3(seg);
+            ip_hdr->ip_tot_len = htons(sizeof *ip_hdr +
+                                       dp_packet_l4_size(seg));
+            ip_hdr->ip_id = htons(ip_id);
+            ip_hdr->ip_csum = 0;
+            ip_id++;
+        } else {
+            struct ovs_16aligned_ip6_hdr *ip6_hdr = dp_packet_l3(seg);
+
+            ip6_hdr->ip6_ctlun.ip6_un1.ip6_un1_plen = htons(sizeof *ip_hdr
+                                                + dp_packet_l4_size(seg));
+
+        }
+
+        /* Update L4 header. */
+        tcp_hdr = dp_packet_l4(seg);
+        put_16aligned_be32(&tcp_hdr->tcp_seq, htonl(tcp_seq));
+        tcp_seq += seg_len;
+        if (OVS_LIKELY(i < (n_segs - 1))) {
+            /* Reset flags PUSH and FIN unless it is the last segment. */
+            uint16_t tcp_flags = TCP_FLAGS(tcp_hdr->tcp_ctl)
+                                 & ~(TCP_PSH | TCP_FIN);
+            tcp_hdr->tcp_ctl = TCP_CTL(tcp_flags, tcp_offset);
+        }
+
+        if (dp_packet_batch_is_full(&batches[ *batch_pos])) {
+            *batch_pos += 1;
+        }
+
+        dp_packet_batch_add(&batches[ *batch_pos], seg);
+    }
+
+    COVERAGE_INC(soft_seg_good);
+}
diff --git a/lib/dp-packet-gso.h b/lib/dp-packet-gso.h
new file mode 100644
index 000000000..81cb52742
--- /dev/null
+++ b/lib/dp-packet-gso.h
@@ -0,0 +1,24 @@ 
+/*
+ * Copyright (c) 2021 Red Hat, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef DP_PACKET_GSO_H
+#define DP_PACKET_GSO_H 1
+
+void dp_packet_gso(struct dp_packet *p, struct dp_packet_batch *batches,
+                   size_t *batch_pos);
+int dp_packet_gso_nr_segs(struct dp_packet *p);
+
+#endif /* dp-packet-gso.h */
diff --git a/lib/dp-packet.h b/lib/dp-packet.h
index 6a924f3ff..dfa9a0d6b 100644
--- a/lib/dp-packet.h
+++ b/lib/dp-packet.h
@@ -86,6 +86,10 @@  enum dp_packet_offload_mask {
     DEF_OL_FLAG(DP_PACKET_OL_TX_SCTP_CKSUM, RTE_MBUF_F_TX_SCTP_CKSUM, 0x800),
     /* Offload IP checksum. */
     DEF_OL_FLAG(DP_PACKET_OL_TX_IP_CKSUM, RTE_MBUF_F_TX_IP_CKSUM, 0x1000),
+    /* External Buffer attached. */
+    DEF_OL_FLAG(DP_PACKET_OL_EXTERNAL, RTE_MBUF_F_EXTERNAL, 0x4000),
+    /* Indirect Buffer attached. */
+    DEF_OL_FLAG(DP_PACKET_OL_INDIRECT, RTE_MBUF_F_INDIRECT, 0x8000),
     /* Adding new field requires adding to DP_PACKET_OL_SUPPORTED_MASK. */
 };
 
@@ -1131,6 +1135,13 @@  dp_packet_hwol_set_tcp_seg(struct dp_packet *b)
     *dp_packet_ol_flags_ptr(b) |= DP_PACKET_OL_TX_TCP_SEG;
 }
 
+/* Resets TCP Segmentation flag in packet 'p'. */
+static inline void
+dp_packet_hwol_reset_tcp_seg(struct dp_packet *p)
+{
+    *dp_packet_ol_flags_ptr(p) &= ~DP_PACKET_OL_TX_TCP_SEG;
+}
+
 /* Returns 'true' if the IP header has good integrity and the
  * checksum in it is complete. */
 static inline bool
diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c
index 1c100c48e..82ce74c45 100644
--- a/lib/netdev-dpdk.c
+++ b/lib/netdev-dpdk.c
@@ -2288,6 +2288,7 @@  static bool
 netdev_dpdk_prep_hwol_packet(struct netdev_dpdk *dev, struct rte_mbuf *mbuf)
 {
     struct dp_packet *pkt = CONTAINER_OF(mbuf, struct dp_packet, mbuf);
+    struct tcp_header *th;
 
     if (!(mbuf->ol_flags & (RTE_MBUF_F_TX_IP_CKSUM | RTE_MBUF_F_TX_L4_MASK
                             | RTE_MBUF_F_TX_TCP_SEG))) {
@@ -2299,27 +2300,38 @@  netdev_dpdk_prep_hwol_packet(struct netdev_dpdk *dev, struct rte_mbuf *mbuf)
     mbuf->l4_len = 0;
     mbuf->outer_l2_len = 0;
     mbuf->outer_l3_len = 0;
+    th = dp_packet_l4(pkt);
 
     if (mbuf->ol_flags & RTE_MBUF_F_TX_TCP_SEG) {
-        struct tcp_header *th = dp_packet_l4(pkt);
-        int hdr_len;
-
         if (!th) {
             VLOG_WARN_RL(&rl, "%s: TCP Segmentation without L4 header"
+                          " pkt len: %"PRIu32"", dev->up.name, mbuf->pkt_len);
+             return false;
+        }
+
+        mbuf->ol_flags |= RTE_MBUF_F_TX_TCP_CKSUM;
+    }
+
+    if (mbuf->ol_flags & RTE_MBUF_F_TX_TCP_CKSUM) {
+        if (!th) {
+            VLOG_WARN_RL(&rl, "%s: TCP offloading without L4 header"
                          " pkt len: %"PRIu32"", dev->up.name, mbuf->pkt_len);
             return false;
         }
 
         mbuf->l4_len = TCP_OFFSET(th->tcp_ctl) * 4;
-        mbuf->ol_flags |= RTE_MBUF_F_TX_TCP_CKSUM;
-        hdr_len = mbuf->l2_len + mbuf->l3_len + mbuf->l4_len;
         mbuf->tso_segsz = dev->mtu - mbuf->l3_len - mbuf->l4_len;
-        if (OVS_UNLIKELY((hdr_len + mbuf->tso_segsz) > dev->max_packet_len)) {
-            VLOG_WARN_RL(&rl, "%s: Oversized TSO packet. "
-                         "hdr: %"PRIu32", gso: %"PRIu32", max len: %"PRIu32"",
-                         dev->up.name, hdr_len, mbuf->tso_segsz,
-                         dev->max_packet_len);
-            return false;
+
+        if (mbuf->ol_flags & RTE_MBUF_F_TX_TCP_SEG) {
+            int hdr_len = mbuf->l2_len + mbuf->l3_len + mbuf->l4_len;
+            if (OVS_UNLIKELY((hdr_len +
+                              mbuf->tso_segsz) > dev->max_packet_len)) {
+                VLOG_WARN_RL(&rl, "%s: Oversized TSO packet. hdr: %"PRIu32", "
+                             "gso: %"PRIu32", max len: %"PRIu32"",
+                             dev->up.name, hdr_len, mbuf->tso_segsz,
+                             dev->max_packet_len);
+                return false;
+            }
         }
 
         if (mbuf->ol_flags & RTE_MBUF_F_TX_IPV4) {
@@ -2707,6 +2719,7 @@  dpdk_copy_dp_packet_to_mbuf(struct rte_mempool *mp, struct dp_packet *pkt_orig)
     mbuf_dest->packet_type = pkt_orig->mbuf.packet_type;
     mbuf_dest->ol_flags |= (pkt_orig->mbuf.ol_flags &
                             ~(RTE_MBUF_F_EXTERNAL | RTE_MBUF_F_INDIRECT));
+    mbuf_dest->tso_segsz = pkt_orig->mbuf.tso_segsz;
 
     memcpy(&pkt_dest->l2_pad_size, &pkt_orig->l2_pad_size,
            sizeof(struct dp_packet) - offsetof(struct dp_packet, l2_pad_size));
@@ -2765,11 +2778,20 @@  netdev_dpdk_common_send(struct netdev *netdev, struct dp_packet_batch *batch,
     struct rte_mbuf **pkts = (struct rte_mbuf **) batch->packets;
     struct netdev_dpdk *dev = netdev_dpdk_cast(netdev);
     size_t cnt, pkt_cnt = dp_packet_batch_size(batch);
+    struct dp_packet *packet;
+    bool need_copy = false;
 
     memset(stats, 0, sizeof *stats);
 
+    DP_PACKET_BATCH_FOR_EACH (i, packet, batch) {
+        if (packet->source != DPBUF_DPDK) {
+            need_copy = true;
+            break;
+        }
+    }
+
     /* Copy dp-packets to mbufs. */
-    if (OVS_UNLIKELY(batch->packets[0]->source != DPBUF_DPDK)) {
+    if (OVS_UNLIKELY(need_copy)) {
         cnt = dpdk_copy_batch_to_mbuf(netdev, batch);
         stats->tx_failure_drops += pkt_cnt - cnt;
         pkt_cnt = cnt;
diff --git a/lib/netdev-linux.c b/lib/netdev-linux.c
index 82e75cec3..aa957eaeb 100644
--- a/lib/netdev-linux.c
+++ b/lib/netdev-linux.c
@@ -6849,55 +6849,6 @@  af_packet_sock(void)
     return sock;
 }
 
-static int
-netdev_linux_parse_l2(struct dp_packet *b, uint16_t *l4proto)
-{
-    struct eth_header *eth_hdr;
-    ovs_be16 eth_type;
-    int l2_len;
-
-    eth_hdr = dp_packet_at(b, 0, ETH_HEADER_LEN);
-    if (!eth_hdr) {
-        return -EINVAL;
-    }
-
-    l2_len = ETH_HEADER_LEN;
-    eth_type = eth_hdr->eth_type;
-    if (eth_type_vlan(eth_type)) {
-        struct vlan_header *vlan = dp_packet_at(b, l2_len, VLAN_HEADER_LEN);
-
-        if (!vlan) {
-            return -EINVAL;
-        }
-
-        eth_type = vlan->vlan_next_type;
-        l2_len += VLAN_HEADER_LEN;
-    }
-
-    if (eth_type == htons(ETH_TYPE_IP)) {
-        struct ip_header *ip_hdr = dp_packet_at(b, l2_len, IP_HEADER_LEN);
-
-        if (!ip_hdr) {
-            return -EINVAL;
-        }
-
-        *l4proto = ip_hdr->ip_proto;
-        dp_packet_hwol_set_tx_ipv4(b);
-    } else if (eth_type == htons(ETH_TYPE_IPV6)) {
-        struct ovs_16aligned_ip6_hdr *nh6;
-
-        nh6 = dp_packet_at(b, l2_len, IPV6_HEADER_LEN);
-        if (!nh6) {
-            return -EINVAL;
-        }
-
-        *l4proto = nh6->ip6_ctlun.ip6_un1.ip6_un1_nxt;
-        dp_packet_hwol_set_tx_ipv6(b);
-    }
-
-    return 0;
-}
-
 /* Initializes packet 'b' with features enabled in the prepended
  * struct virtio_net_hdr.  Returns 0 if successful, otherwise a
  * positive errno value. */
@@ -6915,15 +6866,6 @@  netdev_linux_parse_vnet_hdr(struct dp_packet *b)
     }
 
     if (vnet->flags == VIRTIO_NET_HDR_F_NEEDS_CSUM) {
-        uint16_t l4proto = 0;
-
-        if (netdev_linux_parse_l2(b, &l4proto)) {
-            return EINVAL;
-        }
-
-        if (l4proto == IPPROTO_UDP) {
-            dp_packet_hwol_set_csum_udp(b);
-        }
         /* The packet has offloaded checksum. However, there is no
          * additional information like the protocol used, so it would
          * require to parse the packet here. The checksum starting point
diff --git a/lib/netdev.c b/lib/netdev.c
index 8df7f8737..8eda6873d 100644
--- a/lib/netdev.c
+++ b/lib/netdev.c
@@ -35,6 +35,7 @@ 
 #include "coverage.h"
 #include "dpif.h"
 #include "dp-packet.h"
+#include "dp-packet-gso.h"
 #include "openvswitch/dynamic-string.h"
 #include "fatal-signal.h"
 #include "hash.h"
@@ -56,6 +57,7 @@ 
 #include "svec.h"
 #include "openvswitch/vlog.h"
 #include "flow.h"
+#include "userspace-tso.h"
 #include "util.h"
 #ifdef __linux__
 #include "tc.h"
@@ -67,7 +69,6 @@  COVERAGE_DEFINE(netdev_received);
 COVERAGE_DEFINE(netdev_sent);
 COVERAGE_DEFINE(netdev_add_router);
 COVERAGE_DEFINE(netdev_get_stats);
-COVERAGE_DEFINE(netdev_send_prepare_drops);
 COVERAGE_DEFINE(netdev_push_header_drops);
 
 struct netdev_saved_flags {
@@ -792,60 +793,67 @@  netdev_get_pt_mode(const struct netdev *netdev)
             : NETDEV_PT_LEGACY_L2);
 }
 
-/* Check if a 'packet' is compatible with 'netdev_flags'.
- * If a packet is incompatible, return 'false' with the 'errormsg'
- * pointing to a reason. */
-static bool
-netdev_send_prepare_packet(const uint64_t netdev_flags,
-                           struct dp_packet *packet, char **errormsg)
-{
-    if (dp_packet_hwol_is_tso(packet)
-        && !(netdev_flags & NETDEV_TX_OFFLOAD_TCP_TSO)) {
-            /* Fall back to GSO in software. */
-            VLOG_ERR_BUF(errormsg, "No TSO support");
-            return false;
-    }
-
-    /* Packet with IP csum offloading enabled was received with verified csum.
-     * Leave the IP csum offloading enabled even with good checksum to the
-     * netdev to decide what would be the best to do.
-     * Provide a software fallback in case the device doesn't support IP csum
-     * offloading. Note: Encapsulated packet must have the inner IP header
-     * csum already calculated.
-     * Packet with L4 csum offloading enabled was received with verified csum.
-     * Leave the L4 csum offloading enabled even with good checksum for the
-     * netdev to decide what would be the best to do.
-     * Netdev that requires pseudo header csum needs to calculate that.
-     * Provide a software fallback in case the netdev doesn't support L4 csum
-     * offloading. Note: Encapsulated packet must have the inner L4 header
-     * csum already calculated. */
-    dp_packet_ol_send_prepare(packet, netdev_flags);
-
-    return true;
-}
-
-/* Check if each packet in 'batch' is compatible with 'netdev' features,
- * otherwise either fall back to software implementation or drop it. */
-static void
-netdev_send_prepare_batch(const struct netdev *netdev,
-                          struct dp_packet_batch *batch)
+static int
+netdev_send_tso(struct netdev *netdev, int qid,
+                struct dp_packet_batch *batch, bool concurrent_txq)
 {
+    struct dp_packet_batch *batches;
     struct dp_packet *packet;
-    size_t i, size = dp_packet_batch_size(batch);
+    int n_packets;
+    int n_batches;
+    int error;
 
-    DP_PACKET_BATCH_REFILL_FOR_EACH (i, size, packet, batch) {
-        char *errormsg = NULL;
+    /* Calculate the total number of packets in the batch after
+     * the segmentation. */
+    n_packets = 0;
+    DP_PACKET_BATCH_FOR_EACH (i, packet, batch) {
+        if (dp_packet_hwol_is_tso(packet)) {
+            n_packets += dp_packet_gso_nr_segs(packet);
+        } else {
+            n_packets++;
+        }
+    }
 
-        if (netdev_send_prepare_packet(netdev->ol_flags, packet, &errormsg)) {
-            dp_packet_batch_refill(batch, packet, i);
+    if (!n_packets) {
+        return 0;
+    }
+
+    /* Allocate enough batches to store all the packets in order. */
+    n_batches = DIV_ROUND_UP(n_packets, NETDEV_MAX_BURST);
+    batches = xmalloc(n_batches * sizeof(struct dp_packet_batch));
+    size_t batch_pos = 0;
+    for (batch_pos = 0; batch_pos < n_batches; batch_pos++) {
+        dp_packet_batch_init(&batches[batch_pos]);
+    }
+    /* Do the packet segmentation if TSO is flagged. */
+    size_t size = dp_packet_batch_size(batch);
+    size_t k;
+    batch_pos = 0;
+    DP_PACKET_BATCH_REFILL_FOR_EACH (k, size, packet, batch) {
+        if (dp_packet_hwol_is_tso(packet)) {
+            dp_packet_gso(packet, batches, &batch_pos);
         } else {
-            dp_packet_delete(packet);
-            COVERAGE_INC(netdev_send_prepare_drops);
-            VLOG_WARN_RL(&rl, "%s: Packet dropped: %s",
-                         netdev_get_name(netdev), errormsg);
-            free(errormsg);
+            if (dp_packet_batch_is_full(&batches[batch_pos])) {
+                batch_pos++;
+            }
+
+            dp_packet_batch_add(&batches[batch_pos], packet);
+        }
+    }
+
+    for (batch_pos = 0; batch_pos < n_batches; batch_pos++) {
+        DP_PACKET_BATCH_FOR_EACH (i, packet, (&batches[batch_pos])) {
+            dp_packet_ol_send_prepare(packet, netdev->ol_flags);
+        }
+
+        error = netdev->netdev_class->send(netdev, qid, &batches[batch_pos],
+                                           concurrent_txq);
+        if (!error) {
+            COVERAGE_INC(netdev_sent);
         }
     }
+    free(batches);
+    return 0;
 }
 
 /* Sends 'batch' on 'netdev'.  Returns 0 if successful (for every packet),
@@ -877,11 +885,21 @@  int
 netdev_send(struct netdev *netdev, int qid, struct dp_packet_batch *batch,
             bool concurrent_txq)
 {
+    const uint64_t netdev_flags = netdev->ol_flags;
+    struct dp_packet *packet;
     int error;
 
-    netdev_send_prepare_batch(netdev, batch);
-    if (OVS_UNLIKELY(dp_packet_batch_is_empty(batch))) {
-        return 0;
+    if (userspace_tso_enabled() &&
+        !(netdev_flags & NETDEV_TX_OFFLOAD_TCP_TSO)) {
+        DP_PACKET_BATCH_FOR_EACH (i, packet, batch) {
+            if (dp_packet_hwol_is_tso(packet)) {
+                return netdev_send_tso(netdev, qid, batch, concurrent_txq);
+            }
+        }
+    }
+
+    DP_PACKET_BATCH_FOR_EACH (i, packet, batch) {
+        dp_packet_ol_send_prepare(packet, netdev_flags);
     }
 
     error = netdev->netdev_class->send(netdev, qid, batch, concurrent_txq);
diff --git a/lib/packets.c b/lib/packets.c
index 462b51f92..dab823ba2 100644
--- a/lib/packets.c
+++ b/lib/packets.c
@@ -427,7 +427,7 @@  add_mpls(struct dp_packet *packet, ovs_be16 ethtype, ovs_be32 lse,
     }
 
     if (!l3_encap) {
-        struct mpls_hdr *header = dp_packet_push_uninit(packet, MPLS_HLEN);
+        struct mpls_hdr *header = dp_packet_resize_l2(packet, MPLS_HLEN);
 
         put_16aligned_be32(&header->mpls_lse, lse);
         packet->l2_5_ofs = 0;
@@ -513,7 +513,7 @@  push_nsh(struct dp_packet *packet, const struct nsh_hdr *nsh_hdr_src)
             OVS_NOT_REACHED();
     }
 
-    nsh = (struct nsh_hdr *) dp_packet_push_uninit(packet, length);
+    nsh = (struct nsh_hdr *) dp_packet_resize_l2(packet, length);
     memcpy(nsh, nsh_hdr_src, length);
     nsh->next_proto = next_proto;
     packet->packet_type = htonl(PT_NSH);