Commit 95d0d094 authored by Qingfang Deng's avatar Qingfang Deng Committed by Jakub Kicinski
Browse files

ppp: use IFF_NO_QUEUE in virtual interfaces 



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.

While at it, remove the usused latency member from struct ppp_channel.

Signed-off-by: default avatarQingfang Deng <dqfext@gmail.com>
Reviewed-by: default avatarToke Høiland-Jørgensen <toke@redhat.com>
Link: https://patch.msgid.link/20250301135517.695809-1-dqfext@gmail.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 00d66b5f

drivers/net/ppp/ppp_generic.c

+4 −0
Original line number Diff line number Diff line
@@ -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;

drivers/net/ppp/pppoe.c

+1 −0
Original line number Diff line number Diff line
@@ -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) {

drivers/net/ppp/pptp.c

+1 −0
Original line number Diff line number Diff line
@@ -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);

include/linux/ppp_channel.h

+1 −2
Original line number Diff line number Diff line
@@ -42,8 +42,7 @@ struct ppp_channel { 
	int		hdrlen;		/* amount of headroom channel needs */

	void		*ppp;		/* opaque to 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__

net/l2tp/l2tp_ppp.c

+1 −0
Original line number Diff line number Diff line
@@ -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) {