Commit 7c862ee9 authored by Marc Kleine-Budde's avatar Marc Kleine-Budde
Browse files

Merge patch series "can: slcan: extend supported features (step 2)" 

Dario Binacchi <dario.binacchi@amarulasolutions.com> says:

====================

With this series I try to finish the task, started with the series [1],
of completely removing the dependency of the slcan driver from the
userspace slcand/slcan_attach applications.

The series also contains patches that remove the legacy stuff (slcan_devs,
SLCAN_MAGIC, ...) and do some module cleanup.

The series has been created on top of the patches:

can: slcan: convert comments to network style comments
can: slcan: slcan_init() convert printk(LEVEL ...) to pr_level()
can: slcan: fix whitespace issues
can: slcan: convert comparison to NULL into !val
can: slcan: clean up if/else
can: slcan: use scnprintf() as a hardening measure
can: slcan: do not report txerr and rxerr during bus-off
can: slcan: do not sleep with a spin lock held

applied to linux-next.

[1] https://lore.kernel.org/all/20220628163137.413025-1-dario.binacchi@amarulasolutions.com

Changes since v3: https://lore.kernel.org/all/20220726210217.3368497-1-dario.binacchi@amarulasolutions.com
- Add Max Staudt's `Reviewed-by' tag.
- Drop the patch "ethtool: add support to get/set CAN bit time register".
- Drop the patch "can: slcan: add support to set bit time register (btr)".
- Remove the RFC prefix from the series.

Changes since v2: https://lore.kernel.org/all/20220725065419.3005015-1-dario.binacchi@amarulasolutions.com
- Update the commit message.
- Use 1 space in front of the =.
- Put the series as RFC again.
- Pick up the patch "can: slcan: use KBUILD_MODNAME and define pr_fmt to replace hardcoded names".
- Add the patch "ethtool: add support to get/set CAN bit time register"
  to the series.
- Add the patch "can: slcan: add support to set bit time register (btr)"
  to the series.
- Replace the link https://marc.info/?l=linux-can&m=165806705927851&w=2 with
  https://lore.kernel.org/all/507b5973-d673-4755-3b64-b41cb9a13b6f@hartkopp.net.
- Add the `Suggested-by' tag.

Changes since RFC: https://lore.kernel.org/all/20220716170007.2020037-1-dario.binacchi@amarulasolutions.com
- Re-add headers that export at least one symbol used by the module.
- Update the commit description.
- Drop the old "slcan" name to use the standard canX interface naming.
- Remove comment on listen-only command.
- Update the commit subject and description.
- Add the patch "MAINTAINERS: Add myself as maintainer of the SLCAN driver"
  to the series.

====================

mkl: rebased to can-next/master

Link: https://lore.kernel.org/all/20220728070254.267974-1-dario.binacchi@amarulasolutions.com


Signed-off-by: default avatarMarc Kleine-Budde <mkl@pengutronix.de>
parents 9d8dd372 4aeccfd8

MAINTAINERS

+6 −0
Original line number Diff line number Diff line
@@ -18470,6 +18470,12 @@ T: git git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab.git 
F:	include/linux/sl?b*.h

F:	mm/sl?b*









SLCAN CAN NETWORK DRIVER









M:	Dario Binacchi <dario.binacchi@amarulasolutions.com>









L:	linux-can@vger.kernel.org









S:	Maintained









F:	drivers/net/can/slcan/

















SLEEPABLE READ-COPY UPDATE (SRCU)









M:	Lai Jiangshan <jiangshanlai@gmail.com>









M:	"Paul E. McKenney" <paulmck@kernel.org>

























drivers/net/can/slcan/slcan-core.c



+138
−321






























Original line number
Diff line number
Diff line









/*









 * slcan.c - serial line CAN interface driver (using tty line discipline)









 *









 * This file is derived from linux/drivers/net/slip/slip.c









 * This file is derived from linux/drivers/net/slip/slip.c and got









 * inspiration from linux/drivers/net/can/can327.c for the rework made









 * on the line discipline code.









 *









 * slip.c Authors  : Laurence Culhane <loz@holmes.demon.co.uk>









 *                   Fred N. van Kempen <waltje@uwalt.nl.mugnet.org>









 * slcan.c Author  : Oliver Hartkopp <socketcan@hartkopp.net>









 * can327.c Author : Max Staudt <max-linux@enpas.org>









 *









 * This program is free software; you can redistribute it and/or modify it









 * under the terms of the GNU General Public License as published by the








@@ -35,8 +38,9 @@







 *









 */



















#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt



















#include <linux/module.h>









#include <linux/moduleparam.h>



















#include <linux/uaccess.h>









#include <linux/bitops.h>








@@ -46,10 +50,6 @@







#include <linux/netdevice.h>









#include <linux/skbuff.h>









#include <linux/rtnetlink.h>









#include <linux/if_arp.h>









#include <linux/if_ether.h>









#include <linux/sched.h>









#include <linux/delay.h>









#include <linux/init.h>









#include <linux/kernel.h>









#include <linux/workqueue.h>








@@ -63,30 +63,22 @@ MODULE_ALIAS_LDISC(N_SLCAN);







MODULE_DESCRIPTION("serial line CAN interface");









MODULE_LICENSE("GPL");









MODULE_AUTHOR("Oliver Hartkopp <socketcan@hartkopp.net>");



















#define SLCAN_MAGIC 0x53CA



















static int maxdev = 10;		/* MAX number of SLCAN channels;









				 * This can be overridden with









				 * insmod slcan.ko maxdev=nnn









				 */









module_param(maxdev, int, 0);









MODULE_PARM_DESC(maxdev, "Maximum number of slcan interfaces");









MODULE_AUTHOR("Dario Binacchi <dario.binacchi@amarulasolutions.com>");



















/* maximum rx buffer len: extended CAN frame with timestamp */









#define SLC_MTU (sizeof("T1111222281122334455667788EA5F\r") + 1)



















#define SLC_CMD_LEN 1









#define SLC_SFF_ID_LEN 3









#define SLC_EFF_ID_LEN 8









#define SLC_STATE_LEN 1









#define SLC_STATE_BE_RXCNT_LEN 3









#define SLC_STATE_BE_TXCNT_LEN 3









#define SLC_STATE_FRAME_LEN       (1 + SLC_CMD_LEN + SLC_STATE_BE_RXCNT_LEN + \









				   SLC_STATE_BE_TXCNT_LEN)









#define SLCAN_MTU (sizeof("T1111222281122334455667788EA5F\r") + 1)



















#define SLCAN_CMD_LEN 1









#define SLCAN_SFF_ID_LEN 3









#define SLCAN_EFF_ID_LEN 8









#define SLCAN_STATE_LEN 1









#define SLCAN_STATE_BE_RXCNT_LEN 3









#define SLCAN_STATE_BE_TXCNT_LEN 3









#define SLCAN_STATE_FRAME_LEN       (1 + SLCAN_CMD_LEN + \









				     SLCAN_STATE_BE_RXCNT_LEN + \









				     SLCAN_STATE_BE_TXCNT_LEN)









struct slcan {









	struct can_priv         can;









	int			magic;



















	/* Various fields. */









	struct tty_struct	*tty;		/* ptr to TTY structure	     */








@@ -95,24 +87,21 @@ struct slcan {







	struct work_struct	tx_work;	/* Flushes transmit buffer   */



















	/* These are pointers to the malloc()ed frame buffers. */









	unsigned char		rbuff[SLC_MTU];	/* receiver buffer	     */









	unsigned char		rbuff[SLCAN_MTU];	/* receiver buffer   */









	int			rcount;         /* received chars counter    */









	unsigned char		xbuff[SLC_MTU];	/* transmitter buffer	     */









	unsigned char		xbuff[SLCAN_MTU];	/* transmitter buffer*/









	unsigned char		*xhead;         /* pointer to next XMIT byte */









	int			xleft;          /* bytes left in XMIT queue  */



















	unsigned long		flags;		/* Flag values/ mode etc     */









#define SLF_INUSE		0		/* Channel in use            */









#define SLF_ERROR		1               /* Parity, etc. error        */









#define SLF_XCMD		2               /* Command transmission      */









#define SLF_ERROR		0               /* Parity, etc. error        */









#define SLF_XCMD		1               /* Command transmission      */









	unsigned long           cmd_flags;      /* Command flags             */









#define CF_ERR_RST		0               /* Reset errors on open      */









	wait_queue_head_t       xcmd_wait;      /* Wait queue for commands   */









						/* transmission              */









};



















static struct net_device **slcan_devs;



















static const u32 slcan_bitrate_const[] = {









	10000, 20000, 50000, 100000, 125000,









	250000, 500000, 800000, 1000000








@@ -179,7 +168,7 @@ int slcan_enable_err_rst_on_open(struct net_device *ndev, bool on)







 *************************************************************************/



















/* Send one completely decapsulated can_frame to the network layer */









static void slc_bump_frame(struct slcan *sl)









static void slcan_bump_frame(struct slcan *sl)









{









	struct sk_buff *skb;









	struct can_frame *cf;








@@ -199,10 +188,10 @@ static void slc_bump_frame(struct slcan *sl)







		fallthrough;









	case 't':









		/* store dlc ASCII value and terminate SFF CAN ID string */









		cf->len = sl->rbuff[SLC_CMD_LEN + SLC_SFF_ID_LEN];









		sl->rbuff[SLC_CMD_LEN + SLC_SFF_ID_LEN] = 0;









		cf->len = sl->rbuff[SLCAN_CMD_LEN + SLCAN_SFF_ID_LEN];









		sl->rbuff[SLCAN_CMD_LEN + SLCAN_SFF_ID_LEN] = 0;









		/* point to payload data behind the dlc */









		cmd += SLC_CMD_LEN + SLC_SFF_ID_LEN + 1;









		cmd += SLCAN_CMD_LEN + SLCAN_SFF_ID_LEN + 1;









		break;









	case 'R':









		cf->can_id = CAN_RTR_FLAG;








@@ -210,16 +199,16 @@ static void slc_bump_frame(struct slcan *sl)







	case 'T':









		cf->can_id |= CAN_EFF_FLAG;









		/* store dlc ASCII value and terminate EFF CAN ID string */









		cf->len = sl->rbuff[SLC_CMD_LEN + SLC_EFF_ID_LEN];









		sl->rbuff[SLC_CMD_LEN + SLC_EFF_ID_LEN] = 0;









		cf->len = sl->rbuff[SLCAN_CMD_LEN + SLCAN_EFF_ID_LEN];









		sl->rbuff[SLCAN_CMD_LEN + SLCAN_EFF_ID_LEN] = 0;









		/* point to payload data behind the dlc */









		cmd += SLC_CMD_LEN + SLC_EFF_ID_LEN + 1;









		cmd += SLCAN_CMD_LEN + SLCAN_EFF_ID_LEN + 1;









		break;









	default:









		goto decode_failed;









	}



















	if (kstrtou32(sl->rbuff + SLC_CMD_LEN, 16, &tmpid))









	if (kstrtou32(sl->rbuff + SLCAN_CMD_LEN, 16, &tmpid))









		goto decode_failed;



















	cf->can_id |= tmpid;








@@ -266,7 +255,7 @@ static void slc_bump_frame(struct slcan *sl)







 * sb256256 : state bus-off: rx counter 256, tx counter 256









 * sa057033 : state active, rx counter 57, tx counter 33









 */









static void slc_bump_state(struct slcan *sl)









static void slcan_bump_state(struct slcan *sl)









{









	struct net_device *dev = sl->dev;









	struct sk_buff *skb;








@@ -292,16 +281,16 @@ static void slc_bump_state(struct slcan *sl)







		return;









	}



















	if (state == sl->can.state || sl->rcount < SLC_STATE_FRAME_LEN)









	if (state == sl->can.state || sl->rcount < SLCAN_STATE_FRAME_LEN)









		return;



















	cmd += SLC_STATE_BE_RXCNT_LEN + SLC_CMD_LEN + 1;









	cmd[SLC_STATE_BE_TXCNT_LEN] = 0;









	cmd += SLCAN_STATE_BE_RXCNT_LEN + SLCAN_CMD_LEN + 1;









	cmd[SLCAN_STATE_BE_TXCNT_LEN] = 0;









	if (kstrtou32(cmd, 10, &txerr))









		return;



















	*cmd = 0;









	cmd -= SLC_STATE_BE_RXCNT_LEN;









	cmd -= SLCAN_STATE_BE_RXCNT_LEN;









	if (kstrtou32(cmd, 10, &rxerr))









		return;


















@@ -330,7 +319,7 @@ static void slc_bump_state(struct slcan *sl)







 * e1a : len 1, errors: ACK error









 * e3bcO: len 3, errors: Bit0 error, CRC error, Tx overrun error









 */









static void slc_bump_err(struct slcan *sl)









static void slcan_bump_err(struct slcan *sl)









{









	struct net_device *dev = sl->dev;









	struct sk_buff *skb;








@@ -346,7 +335,7 @@ static void slc_bump_err(struct slcan *sl)







	else









		return;



















	if ((len + SLC_CMD_LEN + 1) > sl->rcount)









	if ((len + SLCAN_CMD_LEN + 1) > sl->rcount)









		return;



















	skb = alloc_can_err_skb(dev, &cf);








@@ -354,7 +343,7 @@ static void slc_bump_err(struct slcan *sl)







	if (skb)









		cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;



















	cmd += SLC_CMD_LEN + 1;









	cmd += SLCAN_CMD_LEN + 1;









	for (i = 0; i < len; i++, cmd++) {









		switch (*cmd) {









		case 'a':








@@ -443,7 +432,7 @@ static void slc_bump_err(struct slcan *sl)







		netif_rx(skb);









}



















static void slc_bump(struct slcan *sl)









static void slcan_bump(struct slcan *sl)









{









	switch (sl->rbuff[0]) {









	case 'r':








@@ -453,11 +442,11 @@ static void slc_bump(struct slcan *sl)







	case 'R':









		fallthrough;









	case 'T':









		return slc_bump_frame(sl);









		return slcan_bump_frame(sl);









	case 'e':









		return slc_bump_err(sl);









		return slcan_bump_err(sl);









	case 's':









		return slc_bump_state(sl);









		return slcan_bump_state(sl);









	default:









		return;









	}








@@ -469,12 +458,12 @@ static void slcan_unesc(struct slcan *sl, unsigned char s)







	if ((s == '\r') || (s == '\a')) { /* CR or BEL ends the pdu */









		if (!test_and_clear_bit(SLF_ERROR, &sl->flags) &&









		    sl->rcount > 4)









			slc_bump(sl);









			slcan_bump(sl);



















		sl->rcount = 0;









	} else {









		if (!test_bit(SLF_ERROR, &sl->flags))  {









			if (sl->rcount < SLC_MTU)  {









			if (sl->rcount < SLCAN_MTU)  {









				sl->rbuff[sl->rcount++] = s;









				return;









			}








@@ -490,7 +479,7 @@ static void slcan_unesc(struct slcan *sl, unsigned char s)







 *************************************************************************/



















/* Encapsulate one can_frame and stuff into a TTY queue. */









static void slc_encaps(struct slcan *sl, struct can_frame *cf)









static void slcan_encaps(struct slcan *sl, struct can_frame *cf)









{









	int actual, i;









	unsigned char *pos;








@@ -507,11 +496,11 @@ static void slc_encaps(struct slcan *sl, struct can_frame *cf)







	/* determine number of chars for the CAN-identifier */









	if (cf->can_id & CAN_EFF_FLAG) {









		id &= CAN_EFF_MASK;









		endpos = pos + SLC_EFF_ID_LEN;









		endpos = pos + SLCAN_EFF_ID_LEN;









	} else {









		*pos |= 0x20; /* convert R/T to lower case for SFF */









		id &= CAN_SFF_MASK;









		endpos = pos + SLC_SFF_ID_LEN;









		endpos = pos + SLCAN_SFF_ID_LEN;









	}



















	/* build 3 (SFF) or 8 (EFF) digit CAN identifier */








@@ -521,7 +510,8 @@ static void slc_encaps(struct slcan *sl, struct can_frame *cf)







		id >>= 4;









	}



















	pos += (cf->can_id & CAN_EFF_FLAG) ? SLC_EFF_ID_LEN : SLC_SFF_ID_LEN;









	pos += (cf->can_id & CAN_EFF_FLAG) ?









		SLCAN_EFF_ID_LEN : SLCAN_SFF_ID_LEN;



















	*pos++ = cf->len + '0';


















@@ -557,9 +547,8 @@ static void slcan_transmit(struct work_struct *work)

















	spin_lock_bh(&sl->lock);









	/* First make sure we're connected. */









	if (!sl->tty || sl->magic != SLCAN_MAGIC ||









	    (unlikely(!netif_running(sl->dev)) &&









	     likely(!test_bit(SLF_XCMD, &sl->flags)))) {









	if (unlikely(!netif_running(sl->dev)) &&









	    likely(!test_bit(SLF_XCMD, &sl->flags))) {









		spin_unlock_bh(&sl->lock);









		return;









	}








@@ -594,17 +583,14 @@ static void slcan_transmit(struct work_struct *work)







 */









static void slcan_write_wakeup(struct tty_struct *tty)









{









	struct slcan *sl;









	struct slcan *sl = (struct slcan *)tty->disc_data;



















	rcu_read_lock();









	sl = rcu_dereference(tty->disc_data);









	if (sl)









	schedule_work(&sl->tx_work);









	rcu_read_unlock();









}



















/* Send a can_frame to a TTY queue. */









static netdev_tx_t slc_xmit(struct sk_buff *skb, struct net_device *dev)









static netdev_tx_t slcan_netdev_xmit(struct sk_buff *skb,









				     struct net_device *dev)









{









	struct slcan *sl = netdev_priv(dev);


















@@ -623,7 +609,7 @@ static netdev_tx_t slc_xmit(struct sk_buff *skb, struct net_device *dev)







	}



















	netif_stop_queue(sl->dev);









	slc_encaps(sl, (struct can_frame *)skb->data); /* encaps & send */









	slcan_encaps(sl, (struct can_frame *)skb->data); /* encaps & send */









	spin_unlock(&sl->lock);



















out:








@@ -666,18 +652,14 @@ static int slcan_transmit_cmd(struct slcan *sl, const unsigned char *cmd)







}



















/* Netdevice UP -> DOWN routine */









static int slc_close(struct net_device *dev)









static int slcan_netdev_close(struct net_device *dev)









{









	struct slcan *sl = netdev_priv(dev);









	int err;



















	spin_lock_bh(&sl->lock);









	if (sl->tty) {









	if (sl->can.bittiming.bitrate &&









	    sl->can.bittiming.bitrate != CAN_BITRATE_UNKNOWN) {









			spin_unlock_bh(&sl->lock);









		err = slcan_transmit_cmd(sl, "C\r");









			spin_lock_bh(&sl->lock);









		if (err)









			netdev_warn(dev,









				    "failed to send close command 'C\\r'\n");








@@ -685,11 +667,11 @@ static int slc_close(struct net_device *dev)

















	/* TTY discipline is running. */









	clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);









	}









	flush_work(&sl->tx_work);



















	netif_stop_queue(dev);









	sl->rcount   = 0;









	sl->xleft    = 0;









	spin_unlock_bh(&sl->lock);









	close_candev(dev);









	sl->can.state = CAN_STATE_STOPPED;









	if (sl->can.bittiming.bitrate == CAN_BITRATE_UNKNOWN)








@@ -699,15 +681,12 @@ static int slc_close(struct net_device *dev)







}



















/* Netdevice DOWN -> UP routine */









static int slc_open(struct net_device *dev)









static int slcan_netdev_open(struct net_device *dev)









{









	struct slcan *sl = netdev_priv(dev);









	unsigned char cmd[SLC_MTU];









	unsigned char cmd[SLCAN_MTU];









	int err, s;



















	if (!sl->tty)









		return -ENODEV;



















	/* The baud rate is not set with the command









	 * `ip link set <iface> type can bitrate <baud>' and therefore









	 * can.bittiming.bitrate is CAN_BITRATE_UNSET (0), causing








@@ -722,8 +701,6 @@ static int slc_open(struct net_device *dev)







		return err;









	}



















	sl->flags &= BIT(SLF_INUSE);



















	if (sl->can.bittiming.bitrate != CAN_BITRATE_UNKNOWN) {









		for (s = 0; s < ARRAY_SIZE(slcan_bitrate_const); s++) {









			if (sl->can.bittiming.bitrate == slcan_bitrate_const[s])








@@ -751,12 +728,22 @@ static int slc_open(struct net_device *dev)







			}









		}



















		if (sl->can.ctrlmode & CAN_CTRLMODE_LISTENONLY) {









			err = slcan_transmit_cmd(sl, "L\r");









			if (err) {









				netdev_err(dev,









					   "failed to send listen-only command 'L\\r'\n");









				goto cmd_transmit_failed;









			}









		} else {









			err = slcan_transmit_cmd(sl, "O\r");









			if (err) {









			netdev_err(dev, "failed to send open command 'O\\r'\n");









				netdev_err(dev,









					   "failed to send open command 'O\\r'\n");









				goto cmd_transmit_failed;









			}









		}









	}



















	sl->can.state = CAN_STATE_ERROR_ACTIVE;









	netif_start_queue(dev);








@@ -767,24 +754,11 @@ static int slc_open(struct net_device *dev)







	return err;









}



















static void slc_dealloc(struct slcan *sl)









{









	int i = sl->dev->base_addr;



















	free_candev(sl->dev);









	slcan_devs[i] = NULL;









}



















static int slcan_change_mtu(struct net_device *dev, int new_mtu)









{









	return -EINVAL;









}



















static const struct net_device_ops slc_netdev_ops = {









	.ndo_open               = slc_open,









	.ndo_stop               = slc_close,









	.ndo_start_xmit         = slc_xmit,









	.ndo_change_mtu         = slcan_change_mtu,









static const struct net_device_ops slcan_netdev_ops = {









	.ndo_open               = slcan_netdev_open,









	.ndo_stop               = slcan_netdev_close,









	.ndo_start_xmit         = slcan_netdev_xmit,









	.ndo_change_mtu         = can_change_mtu,









};



















/******************************************








@@ -804,7 +778,7 @@ static void slcan_receive_buf(struct tty_struct *tty,







{









	struct slcan *sl = (struct slcan *)tty->disc_data;



















	if (!sl || sl->magic != SLCAN_MAGIC || !netif_running(sl->dev))









	if (!netif_running(sl->dev))









		return;



















	/* Read the characters out of the buffer */








@@ -819,80 +793,15 @@ static void slcan_receive_buf(struct tty_struct *tty,







	}









}



















/************************************









 *  slcan_open helper routines.









 ************************************/



















/* Collect hanged up channels */









static void slc_sync(void)









{









	int i;









	struct net_device *dev;









	struct slcan	  *sl;



















	for (i = 0; i < maxdev; i++) {









		dev = slcan_devs[i];









		if (!dev)









			break;



















		sl = netdev_priv(dev);









		if (sl->tty)









			continue;









		if (dev->flags & IFF_UP)









			dev_close(dev);









	}









}



















/* Find a free SLCAN channel, and link in this `tty' line. */









static struct slcan *slc_alloc(void)









{









	int i;









	struct net_device *dev = NULL;









	struct slcan       *sl;



















	for (i = 0; i < maxdev; i++) {









		dev = slcan_devs[i];









		if (!dev)









			break;









	}



















	/* Sorry, too many, all slots in use */









	if (i >= maxdev)









		return NULL;



















	dev = alloc_candev(sizeof(*sl), 1);









	if (!dev)









		return NULL;



















	snprintf(dev->name, sizeof(dev->name), "slcan%d", i);









	dev->netdev_ops = &slc_netdev_ops;









	dev->ethtool_ops = &slcan_ethtool_ops;









	dev->base_addr  = i;









	sl = netdev_priv(dev);



















	/* Initialize channel control data */









	sl->magic = SLCAN_MAGIC;









	sl->dev	= dev;









	sl->can.bitrate_const = slcan_bitrate_const;









	sl->can.bitrate_const_cnt = ARRAY_SIZE(slcan_bitrate_const);









	spin_lock_init(&sl->lock);









	INIT_WORK(&sl->tx_work, slcan_transmit);









	init_waitqueue_head(&sl->xcmd_wait);









	slcan_devs[i] = dev;



















	return sl;









}



















/* Open the high-level part of the SLCAN channel.









 * This function is called by the TTY module when the









 * SLCAN line discipline is called for.  Because we are









 * sure the tty line exists, we only have to link it to









 * a free SLCAN channel...









 * SLCAN line discipline is called for.









 *









 * Called in process context serialized from other ldisc calls.









 */









static int slcan_open(struct tty_struct *tty)









{









	struct net_device *dev;









	struct slcan *sl;









	int err;


















@@ -902,72 +811,50 @@ static int slcan_open(struct tty_struct *tty)







	if (!tty->ops->write)









		return -EOPNOTSUPP;



















	/* RTnetlink lock is misused here to serialize concurrent









	 * opens of slcan channels. There are better ways, but it is









	 * the simplest one.









	 */









	rtnl_lock();









	dev = alloc_candev(sizeof(*sl), 1);









	if (!dev)









		return -ENFILE;



















	/* Collect hanged up channels. */









	slc_sync();









	sl = netdev_priv(dev);



















	sl = tty->disc_data;









	/* Configure TTY interface */









	tty->receive_room = 65536; /* We don't flow control */









	sl->rcount = 0;









	sl->xleft = 0;









	spin_lock_init(&sl->lock);









	INIT_WORK(&sl->tx_work, slcan_transmit);









	init_waitqueue_head(&sl->xcmd_wait);



















	err = -EEXIST;









	/* First make sure we're not already connected. */









	if (sl && sl->magic == SLCAN_MAGIC)









		goto err_exit;









	/* Configure CAN metadata */









	sl->can.bitrate_const = slcan_bitrate_const;









	sl->can.bitrate_const_cnt = ARRAY_SIZE(slcan_bitrate_const);









	sl->can.ctrlmode_supported = CAN_CTRLMODE_LISTENONLY;



















	/* OK.  Find a free SLCAN channel to use. */









	err = -ENFILE;









	sl = slc_alloc();









	if (!sl)









		goto err_exit;









	/* Configure netdev interface */









	sl->dev	= dev;









	dev->netdev_ops = &slcan_netdev_ops;









	dev->ethtool_ops = &slcan_ethtool_ops;



















	/* Mark ldisc channel as alive */









	sl->tty = tty;









	tty->disc_data = sl;



















	if (!test_bit(SLF_INUSE, &sl->flags)) {









		/* Perform the low-level SLCAN initialization. */









		sl->rcount   = 0;









		sl->xleft    = 0;



















		set_bit(SLF_INUSE, &sl->flags);



















		rtnl_unlock();









		err = register_candev(sl->dev);









	err = register_candev(dev);









	if (err) {









			pr_err("slcan: can't register candev\n");









			goto err_free_chan;









		}









	} else {









		rtnl_unlock();









		free_candev(dev);









		pr_err("can't register candev\n");









		return err;









	}



















	tty->receive_room = 65536;	/* We don't flow control */



















	netdev_info(dev, "slcan on %s.\n", tty->name);









	/* TTY layer expects 0 on success */









	return 0;



















err_free_chan:









	rtnl_lock();









	sl->tty = NULL;









	tty->disc_data = NULL;









	clear_bit(SLF_INUSE, &sl->flags);









	slc_dealloc(sl);









	rtnl_unlock();









	return err;



















err_exit:









	rtnl_unlock();



















	/* Count references from TTY module */









	return err;









}



















/* Close down a SLCAN channel.









 * This means flushing out any pending queues, and then returning. This









 * call is serialized against other ldisc functions.









 * Once this is called, no other ldisc function of ours is entered.









 *









 * We also use this method for a hangup event.









 */








@@ -975,28 +862,20 @@ static void slcan_close(struct tty_struct *tty)







{









	struct slcan *sl = (struct slcan *)tty->disc_data;



















	/* First make sure we're connected. */









	if (!sl || sl->magic != SLCAN_MAGIC || sl->tty != tty)









		return;









	/* unregister_netdev() calls .ndo_stop() so we don't have to.









	 * Our .ndo_stop() also flushes the TTY write wakeup handler,









	 * so we can safely set sl->tty = NULL after this.









	 */









	unregister_candev(sl->dev);



















	/* Mark channel as dead */









	spin_lock_bh(&sl->lock);









	rcu_assign_pointer(tty->disc_data, NULL);









	tty->disc_data = NULL;









	sl->tty = NULL;









	spin_unlock_bh(&sl->lock);



















	synchronize_rcu();









	flush_work(&sl->tx_work);



















	slc_close(sl->dev);









	unregister_candev(sl->dev);









	rtnl_lock();









	slc_dealloc(sl);









	rtnl_unlock();









}



















static void slcan_hangup(struct tty_struct *tty)









{









	slcan_close(tty);









	netdev_info(sl->dev, "slcan off %s.\n", tty->name);









	free_candev(sl->dev);









}



















/* Perform I/O control on an active SLCAN channel. */








@@ -1006,10 +885,6 @@ static int slcan_ioctl(struct tty_struct *tty, unsigned int cmd,







	struct slcan *sl = (struct slcan *)tty->disc_data;









	unsigned int tmp;



















	/* First make sure we're connected. */









	if (!sl || sl->magic != SLCAN_MAGIC)









		return -EINVAL;



















	switch (cmd) {









	case SIOCGIFNAME:









		tmp = strlen(sl->dev->name) + 1;








@@ -1025,13 +900,12 @@ static int slcan_ioctl(struct tty_struct *tty, unsigned int cmd,







	}









}



















static struct tty_ldisc_ops slc_ldisc = {









static struct tty_ldisc_ops slcan_ldisc = {









	.owner		= THIS_MODULE,









	.num		= N_SLCAN,









	.name		= "slcan",









	.name		= KBUILD_MODNAME,









	.open		= slcan_open,









	.close		= slcan_close,









	.hangup		= slcan_hangup,









	.ioctl		= slcan_ioctl,









	.receive_buf	= slcan_receive_buf,









	.write_wakeup	= slcan_write_wakeup,








@@ -1041,79 +915,22 @@ static int __init slcan_init(void)







{









	int status;



















	if (maxdev < 4)









		maxdev = 4; /* Sanity */



















	pr_info("slcan: serial line CAN interface driver\n");









	pr_info("slcan: %d dynamic interface channels.\n", maxdev);



















	slcan_devs = kcalloc(maxdev, sizeof(struct net_device *), GFP_KERNEL);









	if (!slcan_devs)









		return -ENOMEM;









	pr_info("serial line CAN interface driver\n");



















	/* Fill in our line protocol discipline, and register it */









	status = tty_register_ldisc(&slc_ldisc);









	if (status)  {









		pr_err("slcan: can't register line discipline\n");









		kfree(slcan_devs);









	}









	status = tty_register_ldisc(&slcan_ldisc);









	if (status)









		pr_err("can't register line discipline\n");



















	return status;









}



















static void __exit slcan_exit(void)









{









	int i;









	struct net_device *dev;









	struct slcan *sl;









	unsigned long timeout = jiffies + HZ;









	int busy = 0;



















	if (!slcan_devs)









		return;



















	/* First of all: check for active disciplines and hangup them.









	/* This will only be called when all channels have been closed by









	 * userspace - tty_ldisc.c takes care of the module's refcount.









	 */









	do {









		if (busy)









			msleep_interruptible(100);



















		busy = 0;









		for (i = 0; i < maxdev; i++) {









			dev = slcan_devs[i];









			if (!dev)









				continue;









			sl = netdev_priv(dev);









			spin_lock_bh(&sl->lock);









			if (sl->tty) {









				busy++;









				tty_hangup(sl->tty);









			}









			spin_unlock_bh(&sl->lock);









		}









	} while (busy && time_before(jiffies, timeout));



















	/* FIXME: hangup is async so we should wait when doing this second









	 * phase









	 */



















	for (i = 0; i < maxdev; i++) {









		dev = slcan_devs[i];









		if (!dev)









			continue;



















		sl = netdev_priv(dev);









		if (sl->tty)









			netdev_err(dev, "tty discipline still running\n");



















		slc_close(dev);









		unregister_candev(dev);









		slc_dealloc(sl);









	}



















	kfree(slcan_devs);









	slcan_devs = NULL;



















	tty_unregister_ldisc(&slc_ldisc);









	tty_unregister_ldisc(&slcan_ldisc);









}



















module_init(slcan_init);