[PATCH net-next] ppp: pass private data to channel callbacks

[PATCH net-next] ppp: pass private data to channel callbacks

[Qingfang Deng]

PPP channel callbacks receive struct ppp_channel only to retrieve the
driver's private pointer. Pass that pointer directly instead.

Signed-off-by: Qingfang Deng <qingfang.deng@linux.dev>
---
 drivers/net/ppp/ppp_async.c   | 13 ++++++-------
 drivers/net/ppp/ppp_generic.c | 12 ++++++------
 drivers/net/ppp/ppp_synctty.c | 13 ++++++-------
 drivers/net/ppp/pppoe.c       |  8 ++++----
 drivers/net/ppp/pptp.c        |  9 ++++-----
 include/linux/ppp_channel.h   |  6 +++---
 net/atm/pppoatm.c             | 21 ++++++++-------------
 net/l2tp/l2tp_ppp.c           |  6 +++---
 8 files changed, 40 insertions(+), 48 deletions(-)

diff --git a/drivers/net/ppp/ppp_async.c b/drivers/net/ppp/ppp_async.c
index ea7fe9608ffd..e73b0fce86b9 100644
--- a/drivers/net/ppp/ppp_async.c
+++ b/drivers/net/ppp/ppp_async.c
@@ -91,13 +91,12 @@ MODULE_ALIAS_LDISC(N_PPP);
  * Prototypes.
  */
 static int ppp_async_encode(struct asyncppp *ap);
-static int ppp_async_send(struct ppp_channel *chan, struct sk_buff *skb);
+static int ppp_async_send(void *private, struct sk_buff *skb);
 static int ppp_async_push(struct asyncppp *ap);
 static void ppp_async_flush_output(struct asyncppp *ap);
 static void ppp_async_input(struct asyncppp *ap, const unsigned char *buf,
 			    const u8 *flags, int count);
-static int ppp_async_ioctl(struct ppp_channel *chan, unsigned int cmd,
-			   unsigned long arg);
+static int ppp_async_ioctl(void *private, unsigned int cmd, unsigned long arg);
 static void ppp_async_process(struct tasklet_struct *t);
 
 static void async_lcp_peek(struct asyncppp *ap, unsigned char *data,
@@ -321,9 +320,9 @@ ppp_async_init(void)
  * The following routines provide the PPP channel interface.
  */
 static int
-ppp_async_ioctl(struct ppp_channel *chan, unsigned int cmd, unsigned long arg)
+ppp_async_ioctl(void *private, unsigned int cmd, unsigned long arg)
 {
-	struct asyncppp *ap = chan->private;
+	struct asyncppp *ap = private;
 	void __user *argp = (void __user *)arg;
 	int __user *p = argp;
 	int err, val;
@@ -550,9 +549,9 @@ ppp_async_encode(struct asyncppp *ap)
  * at some later time.
  */
 static int
-ppp_async_send(struct ppp_channel *chan, struct sk_buff *skb)
+ppp_async_send(void *private, struct sk_buff *skb)
 {
-	struct asyncppp *ap = chan->private;
+	struct asyncppp *ap = private;
 
 	ppp_async_push(ap);
 
diff --git a/drivers/net/ppp/ppp_generic.c b/drivers/net/ppp/ppp_generic.c
index 1a610a18893b..3b83ff8cf589 100644
--- a/drivers/net/ppp/ppp_generic.c
+++ b/drivers/net/ppp/ppp_generic.c
@@ -790,7 +790,7 @@ static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 			chan = pch->chan;
 			err = -ENOTTY;
 			if (chan && chan->ops->ioctl)
-				err = chan->ops->ioctl(chan, cmd, arg);
+				err = chan->ops->ioctl(chan->private, cmd, arg);
 			mutex_unlock(&pch->chan_sem);
 		}
 		goto out;
@@ -1603,7 +1603,7 @@ static int ppp_fill_forward_path(struct net_device_path_ctx *ctx,
 	if (!chan->ops->fill_forward_path)
 		return -EOPNOTSUPP;
 
-	return chan->ops->fill_forward_path(ctx, path, chan);
+	return chan->ops->fill_forward_path(ctx, path, chan->private);
 }
 
 static const struct net_device_ops ppp_netdev_ops = {
@@ -1932,7 +1932,7 @@ ppp_push(struct ppp *ppp, struct sk_buff *skb)
 			goto out;
 		}
 
-		ret = chan->ops->start_xmit(chan, skb);
+		ret = chan->ops->start_xmit(chan->private, skb);
 
 out:
 		spin_unlock(&pch->downl);
@@ -2142,7 +2142,7 @@ static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb)
 		/* try to send it down the channel */
 		chan = pch->chan;
 		if (!skb_queue_empty(&pch->file.xq) ||
-			!chan->ops->start_xmit(chan, frag))
+			!chan->ops->start_xmit(chan->private, frag))
 			skb_queue_tail(&pch->file.xq, frag);
 		pch->had_frag = 1;
 		p += flen;
@@ -2175,7 +2175,7 @@ static void __ppp_channel_push(struct channel *pch, struct ppp *ppp)
 	if (pch->chan) {
 		while (!skb_queue_empty(&pch->file.xq)) {
 			skb = skb_dequeue(&pch->file.xq);
-			if (!pch->chan->ops->start_xmit(pch->chan, skb)) {
+			if (!pch->chan->ops->start_xmit(pch->chan->private, skb)) {
 				/* put the packet back and try again later */
 				skb_queue_head(&pch->file.xq, skb);
 				break;
@@ -2300,7 +2300,7 @@ static bool ppp_channel_bridge_input(struct channel *pch, struct sk_buff *skb)
 	}
 
 	skb_scrub_packet(skb, !net_eq(pch->chan_net, pchb->chan_net));
-	if (!pchb->chan->ops->start_xmit(pchb->chan, skb))
+	if (!pchb->chan->ops->start_xmit(pchb->chan->private, skb))
 		kfree_skb(skb);
 
 outl:
diff --git a/drivers/net/ppp/ppp_synctty.c b/drivers/net/ppp/ppp_synctty.c
index f87d43faeeab..54d8402e18c4 100644
--- a/drivers/net/ppp/ppp_synctty.c
+++ b/drivers/net/ppp/ppp_synctty.c
@@ -81,9 +81,8 @@ struct syncppp {
  * Prototypes.
  */
 static struct sk_buff* ppp_sync_txmunge(struct syncppp *ap, struct sk_buff *);
-static int ppp_sync_send(struct ppp_channel *chan, struct sk_buff *skb);
-static int ppp_sync_ioctl(struct ppp_channel *chan, unsigned int cmd,
-			  unsigned long arg);
+static int ppp_sync_send(void *private, struct sk_buff *skb);
+static int ppp_sync_ioctl(void *private, unsigned int cmd, unsigned long arg);
 static void ppp_sync_process(struct tasklet_struct *t);
 static int ppp_sync_push(struct syncppp *ap);
 static void ppp_sync_flush_output(struct syncppp *ap);
@@ -312,9 +311,9 @@ ppp_sync_init(void)
  * The following routines provide the PPP channel interface.
  */
 static int
-ppp_sync_ioctl(struct ppp_channel *chan, unsigned int cmd, unsigned long arg)
+ppp_sync_ioctl(void *private, unsigned int cmd, unsigned long arg)
 {
-	struct syncppp *ap = chan->private;
+	struct syncppp *ap = private;
 	int err, val;
 	u32 accm[8];
 	void __user *argp = (void __user *)arg;
@@ -491,9 +490,9 @@ ppp_sync_txmunge(struct syncppp *ap, struct sk_buff *skb)
  * at some later time.
  */
 static int
-ppp_sync_send(struct ppp_channel *chan, struct sk_buff *skb)
+ppp_sync_send(void *private, struct sk_buff *skb)
 {
-	struct syncppp *ap = chan->private;
+	struct syncppp *ap = private;
 
 	ppp_sync_push(ap);
 
diff --git a/drivers/net/ppp/pppoe.c b/drivers/net/ppp/pppoe.c
index bf7414b46a26..758453503525 100644
--- a/drivers/net/ppp/pppoe.c
+++ b/drivers/net/ppp/pppoe.c
@@ -841,9 +841,9 @@ static int pppoe_sendmsg(struct socket *sock, struct msghdr *m,
  * sends PPP frame over PPPoE socket
  *
  ***********************************************************************/
-static int pppoe_xmit(struct ppp_channel *chan, struct sk_buff *skb)
+static int pppoe_xmit(void *private, struct sk_buff *skb)
 {
-	struct sock *sk = chan->private;
+	struct sock *sk = private;
 	struct pppox_sock *po = pppox_sk(sk);
 	struct net_device *dev = po->pppoe_dev;
 	struct pppoe_hdr *ph;
@@ -895,9 +895,9 @@ static int pppoe_xmit(struct ppp_channel *chan, struct sk_buff *skb)
 
 static int pppoe_fill_forward_path(struct net_device_path_ctx *ctx,
 				   struct net_device_path *path,
-				   const struct ppp_channel *chan)
+				   void *private)
 {
-	struct sock *sk = chan->private;
+	struct sock *sk = private;
 	struct pppox_sock *po = pppox_sk(sk);
 	struct net_device *dev = po->pppoe_dev;
 
diff --git a/drivers/net/ppp/pptp.c b/drivers/net/ppp/pptp.c
index a797a0606f6b..8f7190d7067e 100644
--- a/drivers/net/ppp/pptp.c
+++ b/drivers/net/ppp/pptp.c
@@ -146,9 +146,9 @@ static struct rtable *pptp_route_output(const struct pppox_sock *po,
 	return ip_route_output_flow(net, fl4, sk);
 }
 
-static int pptp_xmit(struct ppp_channel *chan, struct sk_buff *skb)
+static int pptp_xmit(void *private, struct sk_buff *skb)
 {
-	struct sock *sk = chan->private;
+	struct sock *sk = private;
 	struct pppox_sock *po = pppox_sk(sk);
 	struct net *net = sock_net(sk);
 	struct pptp_opt *opt = &po->proto.pptp;
@@ -573,10 +573,9 @@ static int pptp_create(struct net *net, struct socket *sock, int kern)
 	return error;
 }
 
-static int pptp_ppp_ioctl(struct ppp_channel *chan, unsigned int cmd,
-	unsigned long arg)
+static int pptp_ppp_ioctl(void *private, unsigned int cmd, unsigned long arg)
 {
-	struct sock *sk = chan->private;
+	struct sock *sk = private;
 	struct pppox_sock *po = pppox_sk(sk);
 	struct pptp_opt *opt = &po->proto.pptp;
 	void __user *argp = (void __user *)arg;
diff --git a/include/linux/ppp_channel.h b/include/linux/ppp_channel.h
index 2f63e9a6cc88..d9cfb8ef0ffa 100644
--- a/include/linux/ppp_channel.h
+++ b/include/linux/ppp_channel.h
@@ -27,12 +27,12 @@ struct ppp_channel;
 struct ppp_channel_ops {
 	/* Send a packet (or multilink fragment) on this channel.
 	   Returns 1 if it was accepted, 0 if not. */
-	int	(*start_xmit)(struct ppp_channel *, struct sk_buff *);
+	int	(*start_xmit)(void *, struct sk_buff *);
 	/* Handle an ioctl call that has come in via /dev/ppp. */
-	int	(*ioctl)(struct ppp_channel *, unsigned int, unsigned long);
+	int	(*ioctl)(void *, unsigned int, unsigned long);
 	int	(*fill_forward_path)(struct net_device_path_ctx *,
 				     struct net_device_path *,
-				     const struct ppp_channel *);
+				     void *);
 };
 
 struct ppp_channel {
diff --git a/net/atm/pppoatm.c b/net/atm/pppoatm.c
index 6da52d12df68..913324f9685f 100644
--- a/net/atm/pppoatm.c
+++ b/net/atm/pppoatm.c
@@ -91,11 +91,6 @@ static inline struct pppoatm_vcc *atmvcc_to_pvcc(const struct atm_vcc *atmvcc)
 	return (struct pppoatm_vcc *) (atmvcc->user_back);
 }
 
-static inline struct pppoatm_vcc *chan_to_pvcc(const struct ppp_channel *chan)
-{
-	return (struct pppoatm_vcc *) (chan->private);
-}
-
 /*
  * We can't do this directly from our _pop handler, since the ppp code
  * doesn't want to be called in interrupt context, so we do it from
@@ -286,9 +281,9 @@ static int pppoatm_may_send(struct pppoatm_vcc *pvcc, int size)
  * as success, just to be clear what we're really doing.
  */
 #define DROP_PACKET 1
-static int pppoatm_send(struct ppp_channel *chan, struct sk_buff *skb)
+static int pppoatm_send(void *private, struct sk_buff *skb)
 {
-	struct pppoatm_vcc *pvcc = chan_to_pvcc(chan);
+	struct pppoatm_vcc *pvcc = private;
 	struct atm_vcc *vcc;
 	int ret;
 
@@ -366,16 +361,16 @@ static int pppoatm_send(struct ppp_channel *chan, struct sk_buff *skb)
 }
 
 /* This handles ioctls sent to the /dev/ppp interface */
-static int pppoatm_devppp_ioctl(struct ppp_channel *chan, unsigned int cmd,
-	unsigned long arg)
+static int pppoatm_devppp_ioctl(void *private, unsigned int cmd,
+				unsigned long arg)
 {
+	struct pppoatm_vcc *pvcc = private;
+
 	switch (cmd) {
 	case PPPIOCGFLAGS:
-		return put_user(chan_to_pvcc(chan)->flags, (int __user *) arg)
-		    ? -EFAULT : 0;
+		return put_user(pvcc->flags, (int __user *)arg) ? -EFAULT : 0;
 	case PPPIOCSFLAGS:
-		return get_user(chan_to_pvcc(chan)->flags, (int __user *) arg)
-		    ? -EFAULT : 0;
+		return get_user(pvcc->flags, (int __user *)arg) ? -EFAULT : 0;
 	}
 	return -ENOTTY;
 }
diff --git a/net/l2tp/l2tp_ppp.c b/net/l2tp/l2tp_ppp.c
index ef8fdfaf051d..c1cda1d7fbf6 100644
--- a/net/l2tp/l2tp_ppp.c
+++ b/net/l2tp/l2tp_ppp.c
@@ -122,7 +122,7 @@ struct pppol2tp_session {
 	struct sock		*__sk;		/* Copy of .sk, for cleanup */
 };
 
-static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb);
+static int pppol2tp_xmit(void *private, struct sk_buff *skb);
 
 static const struct ppp_channel_ops pppol2tp_chan_ops = {
 	.start_xmit =  pppol2tp_xmit,
@@ -327,9 +327,9 @@ static int pppol2tp_sendmsg(struct socket *sock, struct msghdr *m,
  * the skb it supplied, not our cloned skb. So we take care to always
  * leave the original skb unfreed if we return an error.
  */
-static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb)
+static int pppol2tp_xmit(void *private, struct sk_buff *skb)
 {
-	struct sock *sk = (struct sock *)chan->private;
+	struct sock *sk = private;
 	struct l2tp_session *session;
 	struct l2tp_tunnel *tunnel;
 	int uhlen, headroom;
-- 
2.43.0

Re: [PATCH net-next] ppp: pass private data to channel callbacks

[Jiri Slaby]

Hi,

On 04. 09. 26, 5:11, Qingfang Deng wrote:
> PPP channel callbacks receive struct ppp_channel only to retrieve the
> driver's private pointer. Pass that pointer directly instead.

We had type checking at least. What's the purpose of this patch, actually?

> Signed-off-by: Qingfang Deng <qingfang.deng@linux.dev>
> ---
>   drivers/net/ppp/ppp_async.c   | 13 ++++++-------
>   drivers/net/ppp/ppp_generic.c | 12 ++++++------
>   drivers/net/ppp/ppp_synctty.c | 13 ++++++-------
>   drivers/net/ppp/pppoe.c       |  8 ++++----
>   drivers/net/ppp/pptp.c        |  9 ++++-----
>   include/linux/ppp_channel.h   |  6 +++---
>   net/atm/pppoatm.c             | 21 ++++++++-------------
>   net/l2tp/l2tp_ppp.c           |  6 +++---
>   8 files changed, 40 insertions(+), 48 deletions(-)
> 
> diff --git a/drivers/net/ppp/ppp_async.c b/drivers/net/ppp/ppp_async.c
> index ea7fe9608ffd..e73b0fce86b9 100644
> --- a/drivers/net/ppp/ppp_async.c
> +++ b/drivers/net/ppp/ppp_async.c
> @@ -91,13 +91,12 @@ MODULE_ALIAS_LDISC(N_PPP);
>    * Prototypes.
>    */
>   static int ppp_async_encode(struct asyncppp *ap);
> -static int ppp_async_send(struct ppp_channel *chan, struct sk_buff *skb);
> +static int ppp_async_send(void *private, struct sk_buff *skb);
thanks,
-- 
js
suse labs

Re: [PATCH net-next] ppp: pass private data to channel callbacks

[Qingfang Deng]

On 2026/9/4 11:57, Jiri Slaby wrote:
> Hi,
>
> On 04. 09. 26, 5:11, Qingfang Deng wrote:
>> PPP channel callbacks receive struct ppp_channel only to retrieve the
>> driver's private pointer. Pass that pointer directly instead.
>
> We had type checking at least. What's the purpose of this patch, actually?

The goal is to unify the two channel structs and make it owned by the 
generic PPP layer.

You can view previous discussions here:
https://lore.kernel.org/netdev/20260430090532.244758-2-qingfang.deng@linux.dev/

Kind regards,

Re: [PATCH net-next] ppp: pass private data to channel callbacks

[Andrew Lunn]

On Fri, Sep 04, 2026 at 01:39:49PM +0800, Qingfang Deng wrote:
> On 2026/9/4 11:57, Jiri Slaby wrote:
> > Hi,
> > 
> > On 04. 09. 26, 5:11, Qingfang Deng wrote:
> > > PPP channel callbacks receive struct ppp_channel only to retrieve the
> > > driver's private pointer. Pass that pointer directly instead.
> > 
> > We had type checking at least. What's the purpose of this patch, actually?
> 
> The goal is to unify the two channel structs and make it owned by the
> generic PPP layer.

The commit message is about "Why?". Please add this to the commit
message.


    Andrew

---
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