For PPPoE, PPTP, and PPPoL2TP, the start_xmit() function directly
forwards packets to the underlying network stack and never returns
anything other than 1. So these interfaces do not require a qdisc,
and the IFF_NO_QUEUE flag should be set.
Introduces a direct_xmit flag in struct ppp_channel to indicate when
IFF_NO_QUEUE should be applied. The flag is set in ppp_connect_channel()
for relevant protocols.
Signed-off-by: Qingfang Deng <dqfext@xxxxxxxxx>
---
RFC v1 -> v2: Conditionally set the flag for relevant protocols.
I'm not sure if ppp_connect_channel can be invoked while the device
is still up. As a qdisc is attached in dev_activate() called by
dev_open(), setting the IFF_NO_QUEUE flag on a running device will have
no effect.
drivers/net/ppp/ppp_generic.c | 4 ++++
drivers/net/ppp/pppoe.c | 1 +
drivers/net/ppp/pptp.c | 1 +
include/linux/ppp_channel.h | 1 +
net/l2tp/l2tp_ppp.c | 1 +
5 files changed, 8 insertions(+)
diff --git a/drivers/net/ppp/ppp_generic.c b/drivers/net/ppp/ppp_generic.c
index 6220866258fc..815108c98b78 100644
--- a/drivers/net/ppp/ppp_generic.c
+++ b/drivers/net/ppp/ppp_generic.c
@@ -3493,6 +3493,10 @@ ppp_connect_channel(struct channel *pch, int unit)
ret = -ENOTCONN;
goto outl;
}
+ if (pch->chan->direct_xmit)
+ ppp->dev->priv_flags |= IFF_NO_QUEUE;
+ else
+ ppp->dev->priv_flags &= ~IFF_NO_QUEUE;
spin_unlock_bh(&pch->downl);
if (pch->file.hdrlen > ppp->file.hdrlen)
ppp->file.hdrlen = pch->file.hdrlen;
diff --git a/drivers/net/ppp/pppoe.c b/drivers/net/ppp/pppoe.c
index 2ea4f4890d23..68e631718ab0 100644
--- a/drivers/net/ppp/pppoe.c
+++ b/drivers/net/ppp/pppoe.c
@@ -693,6 +693,7 @@ static int pppoe_connect(struct socket *sock, struct sockaddr *uservaddr,
po->chan.mtu = dev->mtu - sizeof(struct pppoe_hdr) - 2;
po->chan.private = sk;
po->chan.ops = &pppoe_chan_ops;
+ po->chan.direct_xmit = true;
error = ppp_register_net_channel(dev_net(dev), &po->chan);
if (error) {
diff --git a/drivers/net/ppp/pptp.c b/drivers/net/ppp/pptp.c
index 689687bd2574..5feaa70b5f47 100644
--- a/drivers/net/ppp/pptp.c
+++ b/drivers/net/ppp/pptp.c
@@ -465,6 +465,7 @@ static int pptp_connect(struct socket *sock, struct sockaddr *uservaddr,
po->chan.mtu -= PPTP_HEADER_OVERHEAD;
po->chan.hdrlen = 2 + sizeof(struct pptp_gre_header);
+ po->chan.direct_xmit = true;
error = ppp_register_channel(&po->chan);
if (error) {
pr_err("PPTP: failed to register PPP channel (%d)\n", error);
diff --git a/include/linux/ppp_channel.h b/include/linux/ppp_channel.h
index 45e6e427ceb8..3b50802d66fc 100644
--- a/include/linux/ppp_channel.h
+++ b/include/linux/ppp_channel.h
@@ -44,6 +44,7 @@ struct ppp_channel {
int speed; /* transfer rate (bytes/second) */
/* the following is not used at present */
int latency; /* overhead time in milliseconds */
+ bool direct_xmit; /* no qdisc, xmit directly */
};
#ifdef __KERNEL__
diff --git a/net/l2tp/l2tp_ppp.c b/net/l2tp/l2tp_ppp.c
index 53baf2dd5d5d..fc5c2fd8f34c 100644
--- a/net/l2tp/l2tp_ppp.c
+++ b/net/l2tp/l2tp_ppp.c
@@ -806,6 +806,7 @@ static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr,
po->chan.private = sk;
po->chan.ops = &pppol2tp_chan_ops;
po->chan.mtu = pppol2tp_tunnel_mtu(tunnel);
+ po->chan.direct_xmit = true;
error = ppp_register_net_channel(sock_net(sk), &po->chan);
if (error) {
--
2.43.0
