2022-04-22 19:13:56

by Peilin Ye

Subject: [PATCH net-next 1/2] ip_gre: Make GRE and GRETAP devices always NETIF_F_LLTX

From: Peilin Ye <[email protected]>

Recently we made o_seqno atomic_t. Stop special-casing TUNNEL_SEQ, and
always mark GRE[TAP] devices as NETIF_F_LLTX, since we no longer need
the TX lock (&txq->_xmit_lock).

Depends on patch "ip_gre, ip6_gre: Fix race condition on o_seqno in
collect_md mode".

Signed-off-by: Peilin Ye <[email protected]>
---
net/ipv4/ip_gre.c | 50 +++++++++++++++++++++--------------------------
1 file changed, 22 insertions(+), 28 deletions(-)

diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index 8cf86e42c1d1..a81c2964f70b 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -748,6 +748,7 @@ static netdev_tx_t gre_tap_xmit(struct sk_buff *skb,
static void ipgre_link_update(struct net_device *dev, bool set_mtu)
{
struct ip_tunnel *tunnel = netdev_priv(dev);
+ __be16 flags;
int len;

len = tunnel->tun_hlen;
@@ -763,19 +764,15 @@ static void ipgre_link_update(struct net_device *dev, bool set_mtu)
if (set_mtu)
dev->mtu = max_t(int, dev->mtu - len, 68);

- if (!(tunnel->parms.o_flags & TUNNEL_SEQ)) {
- if (!(tunnel->parms.o_flags & TUNNEL_CSUM) ||
- tunnel->encap.type == TUNNEL_ENCAP_NONE) {
- dev->features |= NETIF_F_GSO_SOFTWARE;
- dev->hw_features |= NETIF_F_GSO_SOFTWARE;
- } else {
- dev->features &= ~NETIF_F_GSO_SOFTWARE;
- dev->hw_features &= ~NETIF_F_GSO_SOFTWARE;
- }
- dev->features |= NETIF_F_LLTX;
- } else {
+ flags = tunnel->parms.o_flags;
+
+ if (flags & TUNNEL_SEQ ||
+ (flags & TUNNEL_CSUM && tunnel->encap.type != TUNNEL_ENCAP_NONE)) {
+ dev->features &= ~NETIF_F_GSO_SOFTWARE;
dev->hw_features &= ~NETIF_F_GSO_SOFTWARE;
- dev->features &= ~(NETIF_F_LLTX | NETIF_F_GSO_SOFTWARE);
+ } else {
+ dev->features |= NETIF_F_GSO_SOFTWARE;
+ dev->hw_features |= NETIF_F_GSO_SOFTWARE;
}
}

@@ -949,6 +946,7 @@ static void ipgre_tunnel_setup(struct net_device *dev)
static void __gre_tunnel_init(struct net_device *dev)
{
struct ip_tunnel *tunnel;
+ __be16 flags;

tunnel = netdev_priv(dev);
tunnel->tun_hlen = gre_calc_hlen(tunnel->parms.o_flags);
@@ -957,25 +955,21 @@ static void __gre_tunnel_init(struct net_device *dev)
tunnel->hlen = tunnel->tun_hlen + tunnel->encap_hlen;
dev->needed_headroom = tunnel->hlen + sizeof(tunnel->parms.iph);

- dev->features |= GRE_FEATURES;
+ dev->features |= GRE_FEATURES | NETIF_F_LLTX;
dev->hw_features |= GRE_FEATURES;

- if (!(tunnel->parms.o_flags & TUNNEL_SEQ)) {
- /* TCP offload with GRE SEQ is not supported, nor
- * can we support 2 levels of outer headers requiring
- * an update.
- */
- if (!(tunnel->parms.o_flags & TUNNEL_CSUM) ||
- (tunnel->encap.type == TUNNEL_ENCAP_NONE)) {
- dev->features |= NETIF_F_GSO_SOFTWARE;
- dev->hw_features |= NETIF_F_GSO_SOFTWARE;
- }
+ flags = tunnel->parms.o_flags;

- /* Can use a lockless transmit, unless we generate
- * output sequences
- */
- dev->features |= NETIF_F_LLTX;
- }
+ /* TCP offload with GRE SEQ is not supported, nor can we support 2
+ * levels of outer headers requiring an update.
+ */
+ if (flags & TUNNEL_SEQ)
+ return;
+ if (flags & TUNNEL_CSUM && tunnel->encap.type != TUNNEL_ENCAP_NONE)
+ return;
+
+ dev->features |= NETIF_F_GSO_SOFTWARE;
+ dev->hw_features |= NETIF_F_GSO_SOFTWARE;
}

static int ipgre_tunnel_init(struct net_device *dev)
--
2.20.1