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linux/drivers/net/wan/x25_asy.c
Alan Cox 33f0f88f1c [PATCH] TTY layer buffering revamp 
The API and code have been through various bits of initial review by
serial driver people but they definitely need to live somewhere for a
while so the unconverted drivers can get knocked into shape, existing
drivers that have been updated can be better tuned and bugs whacked out.

This replaces the tty flip buffers with kmalloc objects in rings. In the
normal situation for an IRQ driven serial port at typical speeds the
behaviour is pretty much the same, two buffers end up allocated and the
kernel cycles between them as before.

When there are delays or at high speed we now behave far better as the
buffer pool can grow a bit rather than lose characters. This also means
that we can operate at higher speeds reliably.

For drivers that receive characters in blocks (DMA based, USB and
especially virtualisation) the layer allows a lot of driver specific
code that works around the tty layer with private secondary queues to be
removed. The IBM folks need this sort of layer, the smart serial port
people do, the virtualisers do (because a virtualised tty typically
operates at infinite speed rather than emulating 9600 baud).

Finally many drivers had invalid and unsafe attempts to avoid buffer
overflows by directly invoking tty methods extracted out of the innards
of work queue structs. These are no longer needed and all go away. That
fixes various random hangs with serial ports on overflow.

The other change in here is to optimise the receive_room path that is
used by some callers. It turns out that only one ldisc uses receive room
except asa constant and it updates it far far less than the value is
read. We thus make it a variable not a function call.

I expect the code to contain bugs due to the size alone but I'll be
watching and squashing them and feeding out new patches as it goes.

Because the buffers now dynamically expand you should only run out of
buffering when the kernel runs out of memory for real.  That means a lot of
the horrible hacks high performance drivers used to do just aren't needed any
more.

Description:

tty_insert_flip_char is an old API and continues to work as before, as does
tty_flip_buffer_push() [this is why many drivers dont need modification].  It
does now also return the number of chars inserted

There are also

tty_buffer_request_room(tty, len)

which asks for a buffer block of the length requested and returns the space
found.  This improves efficiency with hardware that knows how much to
transfer.

and tty_insert_flip_string_flags(tty, str, flags, len)

to insert a string of characters and flags

For a smart interface the usual code is

    len = tty_request_buffer_room(tty, amount_hardware_says);
    tty_insert_flip_string(tty, buffer_from_card, len);

More description!

At the moment tty buffers are attached directly to the tty.  This is causing a
lot of the problems related to tty layer locking, also problems at high speed
and also with bursty data (such as occurs in virtualised environments)

I'm working on ripping out the flip buffers and replacing them with a pool of
dynamically allocated buffers.  This allows both for old style "byte I/O"
devices and also helps virtualisation and smart devices where large blocks of
data suddenely materialise and need storing.

So far so good.  Lots of drivers reference tty->flip.*.  Several of them also
call directly and unsafely into function pointers it provides.  This will all
break.  Most drivers can use tty_insert_flip_char which can be kept as an API
but others need more.

At the moment I've added the following interfaces, if people think more will
be needed now is a good time to say

 int tty_buffer_request_room(tty, size)

Try and ensure at least size bytes are available, returns actual room (may be
zero).  At the moment it just uses the flipbuf space but that will change.
Repeated calls without characters being added are not cumulative.  (ie if you
call it with 1, 1, 1, and then 4 you'll have four characters of space.  The
other functions will also try and grow buffers in future but this will be a
more efficient way when you know block sizes.

 int tty_insert_flip_char(tty, ch, flag)

As before insert a character if there is room.  Now returns 1 for success, 0
for failure.

 int tty_insert_flip_string(tty, str, len)

Insert a block of non error characters.  Returns the number inserted.

 int tty_prepare_flip_string(tty, strptr, len)

Adjust the buffer to allow len characters to be added.  Returns a buffer
pointer in strptr and the length available.  This allows for hardware that
needs to use functions like insl or mencpy_fromio.

Signed-off-by: Alan Cox <alan@redhat.com>
Cc: Paul Fulghum <paulkf@microgate.com>
Signed-off-by: Hirokazu Takata <takata@linux-m32r.org>
Signed-off-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: John Hawkes <hawkes@sgi.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-10 08:01:59 -08:00

832 lines
19 KiB
C
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/*
* Things to sort out:
*
* o tbusy handling
* o allow users to set the parameters
* o sync/async switching ?
*
* Note: This does _not_ implement CCITT X.25 asynchronous framing
* recommendations. Its primarily for testing purposes. If you wanted
* to do CCITT then in theory all you need is to nick the HDLC async
* checksum routines from ppp.c
* Changes:
*
* 2000-10-29 Henner Eisen lapb_data_indication() return status.
*/
#include <linux/module.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <linux/bitops.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/in.h>
#include <linux/tty.h>
#include <linux/errno.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/skbuff.h>
#include <linux/if_arp.h>
#include <linux/x25.h>
#include <linux/lapb.h>
#include <linux/init.h>
#include "x25_asy.h"
#include <net/x25device.h>
static struct net_device **x25_asy_devs;
static int x25_asy_maxdev = SL_NRUNIT;
module_param(x25_asy_maxdev, int, 0);
MODULE_LICENSE("GPL");
static int x25_asy_esc(unsigned char *p, unsigned char *d, int len);
static void x25_asy_unesc(struct x25_asy *sl, unsigned char c);
static void x25_asy_setup(struct net_device *dev);
/* Find a free X.25 channel, and link in this `tty' line. */
static struct x25_asy *x25_asy_alloc(void)
{
struct net_device *dev = NULL;
struct x25_asy *sl;
int i;
if (x25_asy_devs == NULL)
return NULL; /* Master array missing ! */
for (i = 0; i < x25_asy_maxdev; i++) {
dev = x25_asy_devs[i];
/* Not allocated ? */
if (dev == NULL)
break;
sl = dev->priv;
/* Not in use ? */
if (!test_and_set_bit(SLF_INUSE, &sl->flags))
return sl;
}
/* Sorry, too many, all slots in use */
if (i >= x25_asy_maxdev)
return NULL;
/* If no channels are available, allocate one */
if (!dev) {
char name[IFNAMSIZ];
sprintf(name, "x25asy%d", i);
dev = alloc_netdev(sizeof(struct x25_asy),
name, x25_asy_setup);
if (!dev)
return NULL;
/* Initialize channel control data */
sl = dev->priv;
dev->base_addr = i;
/* register device so that it can be ifconfig'ed */
if (register_netdev(dev) == 0) {
/* (Re-)Set the INUSE bit. Very Important! */
set_bit(SLF_INUSE, &sl->flags);
x25_asy_devs[i] = dev;
return sl;
} else {
printk("x25_asy_alloc() - register_netdev() failure.\n");
free_netdev(dev);
}
}
return NULL;
}
/* Free an X.25 channel. */
static void x25_asy_free(struct x25_asy *sl)
{
/* Free all X.25 frame buffers. */
kfree(sl->rbuff);
sl->rbuff = NULL;
kfree(sl->xbuff);
sl->xbuff = NULL;
if (!test_and_clear_bit(SLF_INUSE, &sl->flags)) {
printk("%s: x25_asy_free for already free unit.\n", sl->dev->name);
}
}
static int x25_asy_change_mtu(struct net_device *dev, int newmtu)
{
struct x25_asy *sl = dev->priv;
unsigned char *xbuff, *rbuff;
int len = 2* newmtu;
xbuff = (unsigned char *) kmalloc (len + 4, GFP_ATOMIC);
rbuff = (unsigned char *) kmalloc (len + 4, GFP_ATOMIC);
if (xbuff == NULL || rbuff == NULL)
{
printk("%s: unable to grow X.25 buffers, MTU change cancelled.\n",
dev->name);
kfree(xbuff);
kfree(rbuff);
return -ENOMEM;
}
spin_lock_bh(&sl->lock);
xbuff = xchg(&sl->xbuff, xbuff);
if (sl->xleft) {
if (sl->xleft <= len) {
memcpy(sl->xbuff, sl->xhead, sl->xleft);
} else {
sl->xleft = 0;
sl->stats.tx_dropped++;
}
}
sl->xhead = sl->xbuff;
rbuff = xchg(&sl->rbuff, rbuff);
if (sl->rcount) {
if (sl->rcount <= len) {
memcpy(sl->rbuff, rbuff, sl->rcount);
} else {
sl->rcount = 0;
sl->stats.rx_over_errors++;
set_bit(SLF_ERROR, &sl->flags);
}
}
dev->mtu = newmtu;
sl->buffsize = len;
spin_unlock_bh(&sl->lock);
kfree(xbuff);
kfree(rbuff);
return 0;
}
/* Set the "sending" flag. This must be atomic, hence the ASM. */
static inline void x25_asy_lock(struct x25_asy *sl)
{
netif_stop_queue(sl->dev);
}
/* Clear the "sending" flag. This must be atomic, hence the ASM. */
static inline void x25_asy_unlock(struct x25_asy *sl)
{
netif_wake_queue(sl->dev);
}
/* Send one completely decapsulated IP datagram to the IP layer. */
static void x25_asy_bump(struct x25_asy *sl)
{
struct sk_buff *skb;
int count;
int err;
count = sl->rcount;
sl->stats.rx_bytes+=count;
skb = dev_alloc_skb(count+1);
if (skb == NULL)
{
printk("%s: memory squeeze, dropping packet.\n", sl->dev->name);
sl->stats.rx_dropped++;
return;
}
skb_push(skb,1); /* LAPB internal control */
memcpy(skb_put(skb,count), sl->rbuff, count);
skb->protocol = x25_type_trans(skb, sl->dev);
if((err=lapb_data_received(skb->dev, skb))!=LAPB_OK)
{
kfree_skb(skb);
printk(KERN_DEBUG "x25_asy: data received err - %d\n",err);
}
else
{
netif_rx(skb);
sl->dev->last_rx = jiffies;
sl->stats.rx_packets++;
}
}
/* Encapsulate one IP datagram and stuff into a TTY queue. */
static void x25_asy_encaps(struct x25_asy *sl, unsigned char *icp, int len)
{
unsigned char *p;
int actual, count, mtu = sl->dev->mtu;
if (len > mtu)
{ /* Sigh, shouldn't occur BUT ... */
len = mtu;
printk ("%s: truncating oversized transmit packet!\n", sl->dev->name);
sl->stats.tx_dropped++;
x25_asy_unlock(sl);
return;
}
p = icp;
count = x25_asy_esc(p, (unsigned char *) sl->xbuff, len);
/* Order of next two lines is *very* important.
* When we are sending a little amount of data,
* the transfer may be completed inside driver.write()
* routine, because it's running with interrupts enabled.
* In this case we *never* got WRITE_WAKEUP event,
* if we did not request it before write operation.
* 14 Oct 1994 Dmitry Gorodchanin.
*/
sl->tty->flags |= (1 << TTY_DO_WRITE_WAKEUP);
actual = sl->tty->driver->write(sl->tty, sl->xbuff, count);
sl->xleft = count - actual;
sl->xhead = sl->xbuff + actual;
/* VSV */
clear_bit(SLF_OUTWAIT, &sl->flags); /* reset outfill flag */
}
/*
* Called by the driver when there's room for more data. If we have
* more packets to send, we send them here.
*/
static void x25_asy_write_wakeup(struct tty_struct *tty)
{
int actual;
struct x25_asy *sl = (struct x25_asy *) tty->disc_data;
/* First make sure we're connected. */
if (!sl || sl->magic != X25_ASY_MAGIC || !netif_running(sl->dev))
return;
if (sl->xleft <= 0)
{
/* Now serial buffer is almost free & we can start
* transmission of another packet */
sl->stats.tx_packets++;
tty->flags &= ~(1 << TTY_DO_WRITE_WAKEUP);
x25_asy_unlock(sl);
return;
}
actual = tty->driver->write(tty, sl->xhead, sl->xleft);
sl->xleft -= actual;
sl->xhead += actual;
}
static void x25_asy_timeout(struct net_device *dev)
{
struct x25_asy *sl = (struct x25_asy*)(dev->priv);
spin_lock(&sl->lock);
if (netif_queue_stopped(dev)) {
/* May be we must check transmitter timeout here ?
* 14 Oct 1994 Dmitry Gorodchanin.
*/
printk(KERN_WARNING "%s: transmit timed out, %s?\n", dev->name,
(sl->tty->driver->chars_in_buffer(sl->tty) || sl->xleft) ?
"bad line quality" : "driver error");
sl->xleft = 0;
sl->tty->flags &= ~(1 << TTY_DO_WRITE_WAKEUP);
x25_asy_unlock(sl);
}
spin_unlock(&sl->lock);
}
/* Encapsulate an IP datagram and kick it into a TTY queue. */
static int x25_asy_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct x25_asy *sl = (struct x25_asy*)(dev->priv);
int err;
if (!netif_running(sl->dev)) {
printk("%s: xmit call when iface is down\n", dev->name);
kfree_skb(skb);
return 0;
}
switch(skb->data[0])
{
case 0x00:break;
case 0x01: /* Connection request .. do nothing */
if((err=lapb_connect_request(dev))!=LAPB_OK)
printk(KERN_ERR "x25_asy: lapb_connect_request error - %d\n", err);
kfree_skb(skb);
return 0;
case 0x02: /* Disconnect request .. do nothing - hang up ?? */
if((err=lapb_disconnect_request(dev))!=LAPB_OK)
printk(KERN_ERR "x25_asy: lapb_disconnect_request error - %d\n", err);
default:
kfree_skb(skb);
return 0;
}
skb_pull(skb,1); /* Remove control byte */
/*
* If we are busy already- too bad. We ought to be able
* to queue things at this point, to allow for a little
* frame buffer. Oh well...
* -----------------------------------------------------
* I hate queues in X.25 driver. May be it's efficient,
* but for me latency is more important. ;)
* So, no queues !
* 14 Oct 1994 Dmitry Gorodchanin.
*/
if((err=lapb_data_request(dev,skb))!=LAPB_OK)
{
printk(KERN_ERR "lapbeth: lapb_data_request error - %d\n", err);
kfree_skb(skb);
return 0;
}
return 0;
}
/*
* LAPB interface boilerplate
*/
/*
* Called when I frame data arrives. We did the work above - throw it
* at the net layer.
*/
static int x25_asy_data_indication(struct net_device *dev, struct sk_buff *skb)
{
skb->dev->last_rx = jiffies;
return netif_rx(skb);
}
/*
* Data has emerged from the LAPB protocol machine. We don't handle
* busy cases too well. Its tricky to see how to do this nicely -
* perhaps lapb should allow us to bounce this ?
*/
static void x25_asy_data_transmit(struct net_device *dev, struct sk_buff *skb)
{
struct x25_asy *sl=dev->priv;
spin_lock(&sl->lock);
if (netif_queue_stopped(sl->dev) || sl->tty == NULL)
{
spin_unlock(&sl->lock);
printk(KERN_ERR "x25_asy: tbusy drop\n");
kfree_skb(skb);
return;
}
/* We were not busy, so we are now... :-) */
if (skb != NULL)
{
x25_asy_lock(sl);
sl->stats.tx_bytes+=skb->len;
x25_asy_encaps(sl, skb->data, skb->len);
dev_kfree_skb(skb);
}
spin_unlock(&sl->lock);
}
/*
* LAPB connection establish/down information.
*/
static void x25_asy_connected(struct net_device *dev, int reason)
{
struct x25_asy *sl = dev->priv;
struct sk_buff *skb;
unsigned char *ptr;
if ((skb = dev_alloc_skb(1)) == NULL) {
printk(KERN_ERR "lapbeth: out of memory\n");
return;
}
ptr = skb_put(skb, 1);
*ptr = 0x01;
skb->protocol = x25_type_trans(skb, sl->dev);
netif_rx(skb);
sl->dev->last_rx = jiffies;
}
static void x25_asy_disconnected(struct net_device *dev, int reason)
{
struct x25_asy *sl = dev->priv;
struct sk_buff *skb;
unsigned char *ptr;
if ((skb = dev_alloc_skb(1)) == NULL) {
printk(KERN_ERR "x25_asy: out of memory\n");
return;
}
ptr = skb_put(skb, 1);
*ptr = 0x02;
skb->protocol = x25_type_trans(skb, sl->dev);
netif_rx(skb);
sl->dev->last_rx = jiffies;
}
static struct lapb_register_struct x25_asy_callbacks = {
.connect_confirmation = x25_asy_connected,
.connect_indication = x25_asy_connected,
.disconnect_confirmation = x25_asy_disconnected,
.disconnect_indication = x25_asy_disconnected,
.data_indication = x25_asy_data_indication,
.data_transmit = x25_asy_data_transmit,
};
/* Open the low-level part of the X.25 channel. Easy! */
static int x25_asy_open(struct net_device *dev)
{
struct x25_asy *sl = (struct x25_asy*)(dev->priv);
unsigned long len;
int err;
if (sl->tty == NULL)
return -ENODEV;
/*
* Allocate the X.25 frame buffers:
*
* rbuff Receive buffer.
* xbuff Transmit buffer.
*/
len = dev->mtu * 2;
sl->rbuff = (unsigned char *) kmalloc(len + 4, GFP_KERNEL);
if (sl->rbuff == NULL) {
goto norbuff;
}
sl->xbuff = (unsigned char *) kmalloc(len + 4, GFP_KERNEL);
if (sl->xbuff == NULL) {
goto noxbuff;
}
sl->buffsize = len;
sl->rcount = 0;
sl->xleft = 0;
sl->flags &= (1 << SLF_INUSE); /* Clear ESCAPE & ERROR flags */
netif_start_queue(dev);
/*
* Now attach LAPB
*/
if((err=lapb_register(dev, &x25_asy_callbacks))==LAPB_OK)
return 0;
/* Cleanup */
kfree(sl->xbuff);
noxbuff:
kfree(sl->rbuff);
norbuff:
return -ENOMEM;
}
/* Close the low-level part of the X.25 channel. Easy! */
static int x25_asy_close(struct net_device *dev)
{
struct x25_asy *sl = (struct x25_asy*)(dev->priv);
int err;
spin_lock(&sl->lock);
if (sl->tty)
sl->tty->flags &= ~(1 << TTY_DO_WRITE_WAKEUP);
netif_stop_queue(dev);
sl->rcount = 0;
sl->xleft = 0;
if((err=lapb_unregister(dev))!=LAPB_OK)
printk(KERN_ERR "x25_asy_close: lapb_unregister error -%d\n",err);
spin_unlock(&sl->lock);
return 0;
}
/*
* Handle the 'receiver data ready' interrupt.
* This function is called by the 'tty_io' module in the kernel when
* a block of X.25 data has been received, which can now be decapsulated
* and sent on to some IP layer for further processing.
*/
static void x25_asy_receive_buf(struct tty_struct *tty, const unsigned char *cp, char *fp, int count)
{
struct x25_asy *sl = (struct x25_asy *) tty->disc_data;
if (!sl || sl->magic != X25_ASY_MAGIC || !netif_running(sl->dev))
return;
/* Read the characters out of the buffer */
while (count--) {
if (fp && *fp++) {
if (!test_and_set_bit(SLF_ERROR, &sl->flags)) {
sl->stats.rx_errors++;
}
cp++;
continue;
}
x25_asy_unesc(sl, *cp++);
}
}
/*
* Open the high-level part of the X.25 channel.
* This function is called by the TTY module when the
* X.25 line discipline is called for. Because we are
* sure the tty line exists, we only have to link it to
* a free X.25 channel...
*/
static int x25_asy_open_tty(struct tty_struct *tty)
{
struct x25_asy *sl = (struct x25_asy *) tty->disc_data;
int err;
/* First make sure we're not already connected. */
if (sl && sl->magic == X25_ASY_MAGIC) {
return -EEXIST;
}
/* OK. Find a free X.25 channel to use. */
if ((sl = x25_asy_alloc()) == NULL) {
return -ENFILE;
}
sl->tty = tty;
tty->disc_data = sl;
tty->receive_room = 65536;
if (tty->driver->flush_buffer) {
tty->driver->flush_buffer(tty);
}
if (tty->ldisc.flush_buffer) {
tty->ldisc.flush_buffer(tty);
}
/* Restore default settings */
sl->dev->type = ARPHRD_X25;
/* Perform the low-level X.25 async init */
if ((err = x25_asy_open(sl->dev)))
return err;
/* Done. We have linked the TTY line to a channel. */
return sl->dev->base_addr;
}
/*
* Close down an X.25 channel.
* This means flushing out any pending queues, and then restoring the
* TTY line discipline to what it was before it got hooked to X.25
* (which usually is TTY again).
*/
static void x25_asy_close_tty(struct tty_struct *tty)
{
struct x25_asy *sl = (struct x25_asy *) tty->disc_data;
/* First make sure we're connected. */
if (!sl || sl->magic != X25_ASY_MAGIC)
return;
if (sl->dev->flags & IFF_UP)
{
(void) dev_close(sl->dev);
}
tty->disc_data = NULL;
sl->tty = NULL;
x25_asy_free(sl);
}
static struct net_device_stats *x25_asy_get_stats(struct net_device *dev)
{
struct x25_asy *sl = (struct x25_asy*)(dev->priv);
return &sl->stats;
}
/************************************************************************
* STANDARD X.25 ENCAPSULATION *
************************************************************************/
int x25_asy_esc(unsigned char *s, unsigned char *d, int len)
{
unsigned char *ptr = d;
unsigned char c;
/*
* Send an initial END character to flush out any
* data that may have accumulated in the receiver
* due to line noise.
*/
*ptr++ = X25_END; /* Send 10111110 bit seq */
/*
* For each byte in the packet, send the appropriate
* character sequence, according to the X.25 protocol.
*/
while (len-- > 0)
{
switch(c = *s++)
{
case X25_END:
*ptr++ = X25_ESC;
*ptr++ = X25_ESCAPE(X25_END);
break;
case X25_ESC:
*ptr++ = X25_ESC;
*ptr++ = X25_ESCAPE(X25_ESC);
break;
default:
*ptr++ = c;
break;
}
}
*ptr++ = X25_END;
return (ptr - d);
}
static void x25_asy_unesc(struct x25_asy *sl, unsigned char s)
{
switch(s)
{
case X25_END:
if (!test_and_clear_bit(SLF_ERROR, &sl->flags) && (sl->rcount > 2))
{
x25_asy_bump(sl);
}
clear_bit(SLF_ESCAPE, &sl->flags);
sl->rcount = 0;
return;
case X25_ESC:
set_bit(SLF_ESCAPE, &sl->flags);
return;
case X25_ESCAPE(X25_ESC):
case X25_ESCAPE(X25_END):
if (test_and_clear_bit(SLF_ESCAPE, &sl->flags))
s = X25_UNESCAPE(s);
break;
}
if (!test_bit(SLF_ERROR, &sl->flags))
{
if (sl->rcount < sl->buffsize)
{
sl->rbuff[sl->rcount++] = s;
return;
}
sl->stats.rx_over_errors++;
set_bit(SLF_ERROR, &sl->flags);
}
}
/* Perform I/O control on an active X.25 channel. */
static int x25_asy_ioctl(struct tty_struct *tty, struct file *file,
unsigned int cmd, unsigned long arg)
{
struct x25_asy *sl = (struct x25_asy *) tty->disc_data;
/* First make sure we're connected. */
if (!sl || sl->magic != X25_ASY_MAGIC)
return -EINVAL;
switch(cmd) {
case SIOCGIFNAME:
if (copy_to_user((void __user *)arg, sl->dev->name,
strlen(sl->dev->name) + 1))
return -EFAULT;
return 0;
case SIOCSIFHWADDR:
return -EINVAL;
/* Allow stty to read, but not set, the serial port */
case TCGETS:
case TCGETA:
return n_tty_ioctl(tty, file, cmd, arg);
default:
return -ENOIOCTLCMD;
}
}
static int x25_asy_open_dev(struct net_device *dev)
{
struct x25_asy *sl = (struct x25_asy*)(dev->priv);
if(sl->tty==NULL)
return -ENODEV;
return 0;
}
/* Initialise the X.25 driver. Called by the device init code */
static void x25_asy_setup(struct net_device *dev)
{
struct x25_asy *sl = dev->priv;
sl->magic = X25_ASY_MAGIC;
sl->dev = dev;
spin_lock_init(&sl->lock);
set_bit(SLF_INUSE, &sl->flags);
/*
* Finish setting up the DEVICE info.
*/
dev->mtu = SL_MTU;
dev->hard_start_xmit = x25_asy_xmit;
dev->tx_timeout = x25_asy_timeout;
dev->watchdog_timeo = HZ*20;
dev->open = x25_asy_open_dev;
dev->stop = x25_asy_close;
dev->get_stats = x25_asy_get_stats;
dev->change_mtu = x25_asy_change_mtu;
dev->hard_header_len = 0;
dev->addr_len = 0;
dev->type = ARPHRD_X25;
dev->tx_queue_len = 10;
/* New-style flags. */
dev->flags = IFF_NOARP;
}
static struct tty_ldisc x25_ldisc = {
.owner = THIS_MODULE,
.magic = TTY_LDISC_MAGIC,
.name = "X.25",
.open = x25_asy_open_tty,
.close = x25_asy_close_tty,
.ioctl = x25_asy_ioctl,
.receive_buf = x25_asy_receive_buf,
.write_wakeup = x25_asy_write_wakeup,
};
static int __init init_x25_asy(void)
{
if (x25_asy_maxdev < 4)
x25_asy_maxdev = 4; /* Sanity */
printk(KERN_INFO "X.25 async: version 0.00 ALPHA "
"(dynamic channels, max=%d).\n", x25_asy_maxdev );
x25_asy_devs = kmalloc(sizeof(struct net_device *)*x25_asy_maxdev,
GFP_KERNEL);
if (!x25_asy_devs) {
printk(KERN_WARNING "X25 async: Can't allocate x25_asy_ctrls[] "
"array! Uaargh! (-> No X.25 available)\n");
return -ENOMEM;
}
memset(x25_asy_devs, 0, sizeof(struct net_device *)*x25_asy_maxdev);
return tty_register_ldisc(N_X25, &x25_ldisc);
}
static void __exit exit_x25_asy(void)
{
struct net_device *dev;
int i;
for (i = 0; i < x25_asy_maxdev; i++) {
dev = x25_asy_devs[i];
if (dev) {
struct x25_asy *sl = dev->priv;
spin_lock_bh(&sl->lock);
if (sl->tty)
tty_hangup(sl->tty);
spin_unlock_bh(&sl->lock);
/*
* VSV = if dev->start==0, then device
* unregistered while close proc.
*/
unregister_netdev(dev);
free_netdev(dev);
}
}
kfree(x25_asy_devs);
tty_unregister_ldisc(N_X25);
}
module_init(init_x25_asy);
module_exit(exit_x25_asy);
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