Merge tag 'isdn-removal' of https://git.kernel.org/pub/scm/linux/kernel/git/arnd/playground

Arnd Bergmann says:

====================
isdn: deprecate non-mISDN drivers

When isdn4linux came up in the context of another patch series, I
remembered that we had discussed removing it a while ago.

It turns out that the suggestion from Karsten Keil wa to remove I4L
in 2018 after the last public ISDN networks are shut down. This has
happened now (with a very small number of exceptions), so I guess it's
time to try again.

We currently have three ISDN stacks in the kernel: the original
isdn4linux (with the hisax driver), the newer CAPI (with four drivers),
and finally the mISDN stack (supporting roughly the same hardware as
hisax).

As far as I can tell, anyone using ISDN with mainline kernel drivers in
the past few years uses mISDN, and this is typically used for voice-only
PBX installations that don't require a public network.

The older stacks support additional features for data networks, but those
typically make no sense any more if there is no network to connect to.

My proposal for this time is to kill off isdn4linux entirely, as it seems
to have been unusable for quite a while. This code has been abandoned
for many years and it does cause problems for treewide maintenance as
it tends to do everything that we try to stop doing.
Birger Harzenetter mentioned that is is still using i4l in order to
make use of the 'divert' feature that is not part of mISDN, but has
otherwise moved on to mISDN for normal operation, like apparently
everyone else.

CAPI in turn is not quite as obsolete, but two of the drivers (avm
and hysdn) don't seem to be used at all, while another one (gigaset)
will stop being maintained as Paul Bolle is no longer able to
test it after the network gets shut down in September.
All three are now moved into drivers/staging to let others speak
up in case there are remaining users.
This leaves Bluetooth CMTP as the only remaining user of CAPI, but
Marcel Holtmann wishes to keep maintaining it.

For the discussion on version 1, see [2]
Unfortunately, Karsten Keil as the maintainer has not participated in
the discussion.

      Arnd

[1] https://patchwork.kernel.org/patch/8484861/#17900371
[2] https://listserv.isdn4linux.de/pipermail/isdn4linux/2019-April/thread.html
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 0 insertions, 332 deletions

diff --git a/drivers/isdn/i4l/isdn_x25iface.c b/drivers/isdn/i4l/isdn_x25iface.c
deleted file mode 100644
index 48bfbcb4a09d..000000000000
--- a/drivers/isdn/i4l/isdn_x25iface.c
+++ /dev/null
@@ -1,332 +0,0 @@
-/* $Id: isdn_x25iface.c,v 1.1.2.2 2004/01/12 22:37:19 keil Exp $
- *
- * Linux ISDN subsystem, X.25 related functions
- *
- * This software may be used and distributed according to the terms
- * of the GNU General Public License, incorporated herein by reference.
- *
- * stuff needed to support the Linux X.25 PLP code on top of devices that
- * can provide a lab_b service using the concap_proto mechanism.
- * This module supports a network interface which provides lapb_sematics
- * -- as defined in Documentation/networking/x25-iface.txt -- to
- * the upper layer and assumes that the lower layer provides a reliable
- * data link service by means of the concap_device_ops callbacks.
- *
- * Only protocol specific stuff goes here. Device specific stuff
- * goes to another -- device related -- concap_proto support source file.
- *
- */
-
-/* #include <linux/isdn.h> */
-#include <linux/netdevice.h>
-#include <linux/concap.h>
-#include <linux/slab.h>
-#include <linux/wanrouter.h>
-#include <net/x25device.h>
-#include "isdn_x25iface.h"
-
-/* for debugging messages not to cause an oops when device pointer is NULL*/
-#define MY_DEVNAME(dev)  ((dev) ? (dev)->name : "DEVICE UNSPECIFIED")
-
-
-typedef struct isdn_x25iface_proto_data {
-	int magic;
-	enum wan_states state;
-	/* Private stuff, not to be accessed via proto_data. We provide the
-	   other storage for the concap_proto instance here as well,
-	   enabling us to allocate both with just one kmalloc(): */
-	struct concap_proto priv;
-} ix25_pdata_t;
-
-
-
-/* is now in header file (extern): struct concap_proto * isdn_x25iface_proto_new(void); */
-static void isdn_x25iface_proto_del(struct concap_proto *);
-static int isdn_x25iface_proto_close(struct concap_proto *);
-static int isdn_x25iface_proto_restart(struct concap_proto *,
-				       struct net_device *,
-				       struct concap_device_ops *);
-static int isdn_x25iface_xmit(struct concap_proto *, struct sk_buff *);
-static int isdn_x25iface_receive(struct concap_proto *, struct sk_buff *);
-static int isdn_x25iface_connect_ind(struct concap_proto *);
-static int isdn_x25iface_disconn_ind(struct concap_proto *);
-
-
-static struct concap_proto_ops ix25_pops = {
-	.proto_new = &isdn_x25iface_proto_new,
-	.proto_del = &isdn_x25iface_proto_del,
-	.restart = &isdn_x25iface_proto_restart,
-	.close = &isdn_x25iface_proto_close,
-	.encap_and_xmit = &isdn_x25iface_xmit,
-	.data_ind = &isdn_x25iface_receive,
-	.connect_ind = &isdn_x25iface_connect_ind,
-	.disconn_ind = &isdn_x25iface_disconn_ind
-};
-
-/* error message helper function */
-static void illegal_state_warn(unsigned state, unsigned char firstbyte)
-{
-	printk(KERN_WARNING "isdn_x25iface: firstbyte %x illegal in"
-	       "current state %d\n", firstbyte, state);
-}
-
-/* check protocol data field for consistency */
-static int pdata_is_bad(ix25_pdata_t *pda) {
-
-	if (pda  &&  pda->magic == ISDN_X25IFACE_MAGIC) return 0;
-	printk(KERN_WARNING
-	       "isdn_x25iface_xxx: illegal pointer to proto data\n");
-	return 1;
-}
-
-/* create a new x25 interface protocol instance
- */
-struct concap_proto *isdn_x25iface_proto_new(void)
-{
-	ix25_pdata_t *tmp = kmalloc(sizeof(ix25_pdata_t), GFP_KERNEL);
-	IX25DEBUG("isdn_x25iface_proto_new\n");
-	if (tmp) {
-		tmp->magic = ISDN_X25IFACE_MAGIC;
-		tmp->state = WAN_UNCONFIGURED;
-		/* private data space used to hold the concap_proto data.
-		   Only to be accessed via the returned pointer */
-		spin_lock_init(&tmp->priv.lock);
-		tmp->priv.dops       = NULL;
-		tmp->priv.net_dev    = NULL;
-		tmp->priv.pops       = &ix25_pops;
-		tmp->priv.flags      = 0;
-		tmp->priv.proto_data = tmp;
-		return (&(tmp->priv));
-	}
-	return NULL;
-};
-
-/* close the x25iface encapsulation protocol
- */
-static int isdn_x25iface_proto_close(struct concap_proto *cprot) {
-
-	ix25_pdata_t *tmp;
-	int ret = 0;
-	ulong flags;
-
-	if (!cprot) {
-		printk(KERN_ERR "isdn_x25iface_proto_close: "
-		       "invalid concap_proto pointer\n");
-		return -1;
-	}
-	IX25DEBUG("isdn_x25iface_proto_close %s \n", MY_DEVNAME(cprot->net_dev));
-	spin_lock_irqsave(&cprot->lock, flags);
-	cprot->dops    = NULL;
-	cprot->net_dev = NULL;
-	tmp = cprot->proto_data;
-	if (pdata_is_bad(tmp)) {
-		ret = -1;
-	} else {
-		tmp->state = WAN_UNCONFIGURED;
-	}
-	spin_unlock_irqrestore(&cprot->lock, flags);
-	return ret;
-}
-
-/* Delete the x25iface encapsulation protocol instance
- */
-static void isdn_x25iface_proto_del(struct concap_proto *cprot) {
-
-	ix25_pdata_t *tmp;
-
-	IX25DEBUG("isdn_x25iface_proto_del \n");
-	if (!cprot) {
-		printk(KERN_ERR "isdn_x25iface_proto_del: "
-		       "concap_proto pointer is NULL\n");
-		return;
-	}
-	tmp = cprot->proto_data;
-	if (tmp == NULL) {
-		printk(KERN_ERR "isdn_x25iface_proto_del: inconsistent "
-		       "proto_data pointer (maybe already deleted?)\n");
-		return;
-	}
-	/* close if the protocol is still open */
-	if (cprot->dops) isdn_x25iface_proto_close(cprot);
-	/* freeing the storage should be sufficient now. But some additional
-	   settings might help to catch wild pointer bugs */
-	tmp->magic = 0;
-	cprot->proto_data = NULL;
-
-	kfree(tmp);
-	return;
-}
-
-/* (re-)initialize the data structures for x25iface encapsulation
- */
-static int isdn_x25iface_proto_restart(struct concap_proto *cprot,
-				       struct net_device *ndev,
-				       struct concap_device_ops *dops)
-{
-	ix25_pdata_t *pda = cprot->proto_data;
-	ulong flags;
-
-	IX25DEBUG("isdn_x25iface_proto_restart %s \n", MY_DEVNAME(ndev));
-
-	if (pdata_is_bad(pda)) return -1;
-
-	if (!(dops && dops->data_req && dops->connect_req
-	      && dops->disconn_req)) {
-		printk(KERN_WARNING "isdn_x25iface_restart: required dops"
-		       " missing\n");
-		isdn_x25iface_proto_close(cprot);
-		return -1;
-	}
-	spin_lock_irqsave(&cprot->lock, flags);
-	cprot->net_dev = ndev;
-	cprot->pops = &ix25_pops;
-	cprot->dops = dops;
-	pda->state = WAN_DISCONNECTED;
-	spin_unlock_irqrestore(&cprot->lock, flags);
-	return 0;
-}
-
-/* deliver a dl_data frame received from i4l HL driver to the network layer
- */
-static int isdn_x25iface_receive(struct concap_proto *cprot, struct sk_buff *skb)
-{
-	IX25DEBUG("isdn_x25iface_receive %s \n", MY_DEVNAME(cprot->net_dev));
-	if (((ix25_pdata_t *)(cprot->proto_data))
-	    ->state == WAN_CONNECTED) {
-		if (skb_push(skb, 1)) {
-			skb->data[0] = X25_IFACE_DATA;
-			skb->protocol = x25_type_trans(skb, cprot->net_dev);
-			netif_rx(skb);
-			return 0;
-		}
-	}
-	printk(KERN_WARNING "isdn_x25iface_receive %s: not connected, skb dropped\n", MY_DEVNAME(cprot->net_dev));
-	dev_kfree_skb(skb);
-	return -1;
-}
-
-/* a connection set up is indicated by lower layer
- */
-static int isdn_x25iface_connect_ind(struct concap_proto *cprot)
-{
-	struct sk_buff *skb;
-	enum wan_states *state_p
-		= &(((ix25_pdata_t *)(cprot->proto_data))->state);
-	IX25DEBUG("isdn_x25iface_connect_ind %s \n"
-		  , MY_DEVNAME(cprot->net_dev));
-	if (*state_p == WAN_UNCONFIGURED) {
-		printk(KERN_WARNING
-		       "isdn_x25iface_connect_ind while unconfigured %s\n"
-		       , MY_DEVNAME(cprot->net_dev));
-		return -1;
-	}
-	*state_p = WAN_CONNECTED;
-
-	skb = dev_alloc_skb(1);
-	if (skb) {
-		skb_put_u8(skb, X25_IFACE_CONNECT);
-		skb->protocol = x25_type_trans(skb, cprot->net_dev);
-		netif_rx(skb);
-		return 0;
-	} else {
-		printk(KERN_WARNING "isdn_x25iface_connect_ind: "
-		       " out of memory -- disconnecting\n");
-		cprot->dops->disconn_req(cprot);
-		return -1;
-	}
-}
-
-/* a disconnect is indicated by lower layer
- */
-static int isdn_x25iface_disconn_ind(struct concap_proto *cprot)
-{
-	struct sk_buff *skb;
-	enum wan_states *state_p
-		= &(((ix25_pdata_t *)(cprot->proto_data))->state);
-	IX25DEBUG("isdn_x25iface_disconn_ind %s \n", MY_DEVNAME(cprot->net_dev));
-	if (*state_p == WAN_UNCONFIGURED) {
-		printk(KERN_WARNING
-		       "isdn_x25iface_disconn_ind while unconfigured\n");
-		return -1;
-	}
-	if (!cprot->net_dev) return -1;
-	*state_p = WAN_DISCONNECTED;
-	skb = dev_alloc_skb(1);
-	if (skb) {
-		skb_put_u8(skb, X25_IFACE_DISCONNECT);
-		skb->protocol = x25_type_trans(skb, cprot->net_dev);
-		netif_rx(skb);
-		return 0;
-	} else {
-		printk(KERN_WARNING "isdn_x25iface_disconn_ind:"
-		       " out of memory\n");
-		return -1;
-	}
-}
-
-/* process a frame handed over to us from linux network layer. First byte
-   semantics as defined in Documentation/networking/x25-iface.txt
-*/
-static int isdn_x25iface_xmit(struct concap_proto *cprot, struct sk_buff *skb)
-{
-	unsigned char firstbyte = skb->data[0];
-	enum wan_states *state = &((ix25_pdata_t *)cprot->proto_data)->state;
-	int ret = 0;
-	IX25DEBUG("isdn_x25iface_xmit: %s first=%x state=%d\n",
-		  MY_DEVNAME(cprot->net_dev), firstbyte, *state);
-	switch (firstbyte) {
-	case X25_IFACE_DATA:
-		if (*state == WAN_CONNECTED) {
-			skb_pull(skb, 1);
-			netif_trans_update(cprot->net_dev);
-			ret = (cprot->dops->data_req(cprot, skb));
-			/* prepare for future retransmissions */
-			if (ret) skb_push(skb, 1);
-			return ret;
-		}
-		illegal_state_warn(*state, firstbyte);
-		break;
-	case X25_IFACE_CONNECT:
-		if (*state == WAN_DISCONNECTED) {
-			*state = WAN_CONNECTING;
-			ret = cprot->dops->connect_req(cprot);
-			if (ret) {
-				/* reset state and notify upper layer about
-				 * immidiatly failed attempts */
-				isdn_x25iface_disconn_ind(cprot);
-			}
-		} else {
-			illegal_state_warn(*state, firstbyte);
-		}
-		break;
-	case X25_IFACE_DISCONNECT:
-		switch (*state) {
-		case WAN_DISCONNECTED:
-			/* Should not happen. However, give upper layer a
-			   chance to recover from inconstistency  but don't
-			   trust the lower layer sending the disconn_confirm
-			   when already disconnected */
-			printk(KERN_WARNING "isdn_x25iface_xmit: disconnect "
-			       " requested while disconnected\n");
-			isdn_x25iface_disconn_ind(cprot);
-			break; /* prevent infinite loops */
-		case WAN_CONNECTING:
-		case WAN_CONNECTED:
-			*state = WAN_DISCONNECTED;
-			cprot->dops->disconn_req(cprot);
-			break;
-		default:
-			illegal_state_warn(*state, firstbyte);
-		}
-		break;
-	case X25_IFACE_PARAMS:
-		printk(KERN_WARNING "isdn_x25iface_xmit: setting of lapb"
-		       " options not yet supported\n");
-		break;
-	default:
-		printk(KERN_WARNING "isdn_x25iface_xmit: frame with illegal"
-		       " first byte %x ignored:\n", firstbyte);
-	}
-	dev_kfree_skb(skb);
-	return 0;
-}