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net: use NETDEV_TX_OK instead of 0 in ndo_start_xmit() functions
[deliverable/linux.git] / drivers / net / wan / x25_asy.c
1 /*
2 * Things to sort out:
3 *
4 * o tbusy handling
5 * o allow users to set the parameters
6 * o sync/async switching ?
7 *
8 * Note: This does _not_ implement CCITT X.25 asynchronous framing
9 * recommendations. Its primarily for testing purposes. If you wanted
10 * to do CCITT then in theory all you need is to nick the HDLC async
11 * checksum routines from ppp.c
12 * Changes:
13 *
14 * 2000-10-29 Henner Eisen lapb_data_indication() return status.
15 */
16
17 #include <linux/module.h>
18
19 #include <asm/system.h>
20 #include <linux/uaccess.h>
21 #include <linux/bitops.h>
22 #include <linux/string.h>
23 #include <linux/mm.h>
24 #include <linux/interrupt.h>
25 #include <linux/in.h>
26 #include <linux/tty.h>
27 #include <linux/errno.h>
28 #include <linux/netdevice.h>
29 #include <linux/etherdevice.h>
30 #include <linux/skbuff.h>
31 #include <linux/if_arp.h>
32 #include <linux/x25.h>
33 #include <linux/lapb.h>
34 #include <linux/init.h>
35 #include <linux/rtnetlink.h>
36 #include "x25_asy.h"
37
38 #include <net/x25device.h>
39
40 static struct net_device **x25_asy_devs;
41 static int x25_asy_maxdev = SL_NRUNIT;
42
43 module_param(x25_asy_maxdev, int, 0);
44 MODULE_LICENSE("GPL");
45
46 static int x25_asy_esc(unsigned char *p, unsigned char *d, int len);
47 static void x25_asy_unesc(struct x25_asy *sl, unsigned char c);
48 static void x25_asy_setup(struct net_device *dev);
49
50 /* Find a free X.25 channel, and link in this `tty' line. */
51 static struct x25_asy *x25_asy_alloc(void)
52 {
53 struct net_device *dev = NULL;
54 struct x25_asy *sl;
55 int i;
56
57 if (x25_asy_devs == NULL)
58 return NULL; /* Master array missing ! */
59
60 for (i = 0; i < x25_asy_maxdev; i++) {
61 dev = x25_asy_devs[i];
62
63 /* Not allocated ? */
64 if (dev == NULL)
65 break;
66
67 sl = netdev_priv(dev);
68 /* Not in use ? */
69 if (!test_and_set_bit(SLF_INUSE, &sl->flags))
70 return sl;
71 }
72
73
74 /* Sorry, too many, all slots in use */
75 if (i >= x25_asy_maxdev)
76 return NULL;
77
78 /* If no channels are available, allocate one */
79 if (!dev) {
80 char name[IFNAMSIZ];
81 sprintf(name, "x25asy%d", i);
82
83 dev = alloc_netdev(sizeof(struct x25_asy),
84 name, x25_asy_setup);
85 if (!dev)
86 return NULL;
87
88 /* Initialize channel control data */
89 sl = netdev_priv(dev);
90 dev->base_addr = i;
91
92 /* register device so that it can be ifconfig'ed */
93 if (register_netdev(dev) == 0) {
94 /* (Re-)Set the INUSE bit. Very Important! */
95 set_bit(SLF_INUSE, &sl->flags);
96 x25_asy_devs[i] = dev;
97 return sl;
98 } else {
99 printk(KERN_WARNING "x25_asy_alloc() - register_netdev() failure.\n");
100 free_netdev(dev);
101 }
102 }
103 return NULL;
104 }
105
106
107 /* Free an X.25 channel. */
108 static void x25_asy_free(struct x25_asy *sl)
109 {
110 /* Free all X.25 frame buffers. */
111 kfree(sl->rbuff);
112 sl->rbuff = NULL;
113 kfree(sl->xbuff);
114 sl->xbuff = NULL;
115
116 if (!test_and_clear_bit(SLF_INUSE, &sl->flags))
117 printk(KERN_ERR "%s: x25_asy_free for already free unit.\n",
118 sl->dev->name);
119 }
120
121 static int x25_asy_change_mtu(struct net_device *dev, int newmtu)
122 {
123 struct x25_asy *sl = netdev_priv(dev);
124 unsigned char *xbuff, *rbuff;
125 int len = 2 * newmtu;
126
127 xbuff = kmalloc(len + 4, GFP_ATOMIC);
128 rbuff = kmalloc(len + 4, GFP_ATOMIC);
129
130 if (xbuff == NULL || rbuff == NULL) {
131 printk(KERN_WARNING "%s: unable to grow X.25 buffers, MTU change cancelled.\n",
132 dev->name);
133 kfree(xbuff);
134 kfree(rbuff);
135 return -ENOMEM;
136 }
137
138 spin_lock_bh(&sl->lock);
139 xbuff = xchg(&sl->xbuff, xbuff);
140 if (sl->xleft) {
141 if (sl->xleft <= len) {
142 memcpy(sl->xbuff, sl->xhead, sl->xleft);
143 } else {
144 sl->xleft = 0;
145 dev->stats.tx_dropped++;
146 }
147 }
148 sl->xhead = sl->xbuff;
149
150 rbuff = xchg(&sl->rbuff, rbuff);
151 if (sl->rcount) {
152 if (sl->rcount <= len) {
153 memcpy(sl->rbuff, rbuff, sl->rcount);
154 } else {
155 sl->rcount = 0;
156 dev->stats.rx_over_errors++;
157 set_bit(SLF_ERROR, &sl->flags);
158 }
159 }
160
161 dev->mtu = newmtu;
162 sl->buffsize = len;
163
164 spin_unlock_bh(&sl->lock);
165
166 kfree(xbuff);
167 kfree(rbuff);
168 return 0;
169 }
170
171
172 /* Set the "sending" flag. This must be atomic, hence the ASM. */
173
174 static inline void x25_asy_lock(struct x25_asy *sl)
175 {
176 netif_stop_queue(sl->dev);
177 }
178
179
180 /* Clear the "sending" flag. This must be atomic, hence the ASM. */
181
182 static inline void x25_asy_unlock(struct x25_asy *sl)
183 {
184 netif_wake_queue(sl->dev);
185 }
186
187 /* Send one completely decapsulated IP datagram to the IP layer. */
188
189 static void x25_asy_bump(struct x25_asy *sl)
190 {
191 struct net_device *dev = sl->dev;
192 struct sk_buff *skb;
193 int count;
194 int err;
195
196 count = sl->rcount;
197 dev->stats.rx_bytes += count;
198
199 skb = dev_alloc_skb(count+1);
200 if (skb == NULL) {
201 printk(KERN_WARNING "%s: memory squeeze, dropping packet.\n",
202 sl->dev->name);
203 dev->stats.rx_dropped++;
204 return;
205 }
206 skb_push(skb, 1); /* LAPB internal control */
207 memcpy(skb_put(skb, count), sl->rbuff, count);
208 skb->protocol = x25_type_trans(skb, sl->dev);
209 err = lapb_data_received(skb->dev, skb);
210 if (err != LAPB_OK) {
211 kfree_skb(skb);
212 printk(KERN_DEBUG "x25_asy: data received err - %d\n", err);
213 } else {
214 netif_rx(skb);
215 dev->stats.rx_packets++;
216 }
217 }
218
219 /* Encapsulate one IP datagram and stuff into a TTY queue. */
220 static void x25_asy_encaps(struct x25_asy *sl, unsigned char *icp, int len)
221 {
222 unsigned char *p;
223 int actual, count, mtu = sl->dev->mtu;
224
225 if (len > mtu) {
226 /* Sigh, shouldn't occur BUT ... */
227 len = mtu;
228 printk(KERN_DEBUG "%s: truncating oversized transmit packet!\n",
229 sl->dev->name);
230 sl->dev->stats.tx_dropped++;
231 x25_asy_unlock(sl);
232 return;
233 }
234
235 p = icp;
236 count = x25_asy_esc(p, (unsigned char *) sl->xbuff, len);
237
238 /* Order of next two lines is *very* important.
239 * When we are sending a little amount of data,
240 * the transfer may be completed inside driver.write()
241 * routine, because it's running with interrupts enabled.
242 * In this case we *never* got WRITE_WAKEUP event,
243 * if we did not request it before write operation.
244 * 14 Oct 1994 Dmitry Gorodchanin.
245 */
246 set_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
247 actual = sl->tty->ops->write(sl->tty, sl->xbuff, count);
248 sl->xleft = count - actual;
249 sl->xhead = sl->xbuff + actual;
250 /* VSV */
251 clear_bit(SLF_OUTWAIT, &sl->flags); /* reset outfill flag */
252 }
253
254 /*
255 * Called by the driver when there's room for more data. If we have
256 * more packets to send, we send them here.
257 */
258 static void x25_asy_write_wakeup(struct tty_struct *tty)
259 {
260 int actual;
261 struct x25_asy *sl = tty->disc_data;
262
263 /* First make sure we're connected. */
264 if (!sl || sl->magic != X25_ASY_MAGIC || !netif_running(sl->dev))
265 return;
266
267 if (sl->xleft <= 0) {
268 /* Now serial buffer is almost free & we can start
269 * transmission of another packet */
270 sl->dev->stats.tx_packets++;
271 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
272 x25_asy_unlock(sl);
273 return;
274 }
275
276 actual = tty->ops->write(tty, sl->xhead, sl->xleft);
277 sl->xleft -= actual;
278 sl->xhead += actual;
279 }
280
281 static void x25_asy_timeout(struct net_device *dev)
282 {
283 struct x25_asy *sl = netdev_priv(dev);
284
285 spin_lock(&sl->lock);
286 if (netif_queue_stopped(dev)) {
287 /* May be we must check transmitter timeout here ?
288 * 14 Oct 1994 Dmitry Gorodchanin.
289 */
290 printk(KERN_WARNING "%s: transmit timed out, %s?\n", dev->name,
291 (tty_chars_in_buffer(sl->tty) || sl->xleft) ?
292 "bad line quality" : "driver error");
293 sl->xleft = 0;
294 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
295 x25_asy_unlock(sl);
296 }
297 spin_unlock(&sl->lock);
298 }
299
300 /* Encapsulate an IP datagram and kick it into a TTY queue. */
301
302 static int x25_asy_xmit(struct sk_buff *skb, struct net_device *dev)
303 {
304 struct x25_asy *sl = netdev_priv(dev);
305 int err;
306
307 if (!netif_running(sl->dev)) {
308 printk(KERN_ERR "%s: xmit call when iface is down\n",
309 dev->name);
310 kfree_skb(skb);
311 return NETDEV_TX_OK;
312 }
313
314 switch (skb->data[0]) {
315 case 0x00:
316 break;
317 case 0x01: /* Connection request .. do nothing */
318 err = lapb_connect_request(dev);
319 if (err != LAPB_OK)
320 printk(KERN_ERR "x25_asy: lapb_connect_request error - %d\n", err);
321 kfree_skb(skb);
322 return NETDEV_TX_OK;
323 case 0x02: /* Disconnect request .. do nothing - hang up ?? */
324 err = lapb_disconnect_request(dev);
325 if (err != LAPB_OK)
326 printk(KERN_ERR "x25_asy: lapb_disconnect_request error - %d\n", err);
327 default:
328 kfree_skb(skb);
329 return NETDEV_TX_OK;
330 }
331 skb_pull(skb, 1); /* Remove control byte */
332 /*
333 * If we are busy already- too bad. We ought to be able
334 * to queue things at this point, to allow for a little
335 * frame buffer. Oh well...
336 * -----------------------------------------------------
337 * I hate queues in X.25 driver. May be it's efficient,
338 * but for me latency is more important. ;)
339 * So, no queues !
340 * 14 Oct 1994 Dmitry Gorodchanin.
341 */
342
343 err = lapb_data_request(dev, skb);
344 if (err != LAPB_OK) {
345 printk(KERN_ERR "x25_asy: lapb_data_request error - %d\n", err);
346 kfree_skb(skb);
347 return NETDEV_TX_OK;
348 }
349 return NETDEV_TX_OK;
350 }
351
352
353 /*
354 * LAPB interface boilerplate
355 */
356
357 /*
358 * Called when I frame data arrives. We did the work above - throw it
359 * at the net layer.
360 */
361
362 static int x25_asy_data_indication(struct net_device *dev, struct sk_buff *skb)
363 {
364 return netif_rx(skb);
365 }
366
367 /*
368 * Data has emerged from the LAPB protocol machine. We don't handle
369 * busy cases too well. Its tricky to see how to do this nicely -
370 * perhaps lapb should allow us to bounce this ?
371 */
372
373 static void x25_asy_data_transmit(struct net_device *dev, struct sk_buff *skb)
374 {
375 struct x25_asy *sl = netdev_priv(dev);
376
377 spin_lock(&sl->lock);
378 if (netif_queue_stopped(sl->dev) || sl->tty == NULL) {
379 spin_unlock(&sl->lock);
380 printk(KERN_ERR "x25_asy: tbusy drop\n");
381 kfree_skb(skb);
382 return;
383 }
384 /* We were not busy, so we are now... :-) */
385 if (skb != NULL) {
386 x25_asy_lock(sl);
387 dev->stats.tx_bytes += skb->len;
388 x25_asy_encaps(sl, skb->data, skb->len);
389 dev_kfree_skb(skb);
390 }
391 spin_unlock(&sl->lock);
392 }
393
394 /*
395 * LAPB connection establish/down information.
396 */
397
398 static void x25_asy_connected(struct net_device *dev, int reason)
399 {
400 struct x25_asy *sl = netdev_priv(dev);
401 struct sk_buff *skb;
402 unsigned char *ptr;
403
404 skb = dev_alloc_skb(1);
405 if (skb == NULL) {
406 printk(KERN_ERR "x25_asy: out of memory\n");
407 return;
408 }
409
410 ptr = skb_put(skb, 1);
411 *ptr = 0x01;
412
413 skb->protocol = x25_type_trans(skb, sl->dev);
414 netif_rx(skb);
415 }
416
417 static void x25_asy_disconnected(struct net_device *dev, int reason)
418 {
419 struct x25_asy *sl = netdev_priv(dev);
420 struct sk_buff *skb;
421 unsigned char *ptr;
422
423 skb = dev_alloc_skb(1);
424 if (skb == NULL) {
425 printk(KERN_ERR "x25_asy: out of memory\n");
426 return;
427 }
428
429 ptr = skb_put(skb, 1);
430 *ptr = 0x02;
431
432 skb->protocol = x25_type_trans(skb, sl->dev);
433 netif_rx(skb);
434 }
435
436 static struct lapb_register_struct x25_asy_callbacks = {
437 .connect_confirmation = x25_asy_connected,
438 .connect_indication = x25_asy_connected,
439 .disconnect_confirmation = x25_asy_disconnected,
440 .disconnect_indication = x25_asy_disconnected,
441 .data_indication = x25_asy_data_indication,
442 .data_transmit = x25_asy_data_transmit,
443
444 };
445
446
447 /* Open the low-level part of the X.25 channel. Easy! */
448 static int x25_asy_open(struct net_device *dev)
449 {
450 struct x25_asy *sl = netdev_priv(dev);
451 unsigned long len;
452 int err;
453
454 if (sl->tty == NULL)
455 return -ENODEV;
456
457 /*
458 * Allocate the X.25 frame buffers:
459 *
460 * rbuff Receive buffer.
461 * xbuff Transmit buffer.
462 */
463
464 len = dev->mtu * 2;
465
466 sl->rbuff = kmalloc(len + 4, GFP_KERNEL);
467 if (sl->rbuff == NULL)
468 goto norbuff;
469 sl->xbuff = kmalloc(len + 4, GFP_KERNEL);
470 if (sl->xbuff == NULL)
471 goto noxbuff;
472
473 sl->buffsize = len;
474 sl->rcount = 0;
475 sl->xleft = 0;
476 sl->flags &= (1 << SLF_INUSE); /* Clear ESCAPE & ERROR flags */
477
478 netif_start_queue(dev);
479
480 /*
481 * Now attach LAPB
482 */
483 err = lapb_register(dev, &x25_asy_callbacks);
484 if (err == LAPB_OK)
485 return 0;
486
487 /* Cleanup */
488 kfree(sl->xbuff);
489 noxbuff:
490 kfree(sl->rbuff);
491 norbuff:
492 return -ENOMEM;
493 }
494
495
496 /* Close the low-level part of the X.25 channel. Easy! */
497 static int x25_asy_close(struct net_device *dev)
498 {
499 struct x25_asy *sl = netdev_priv(dev);
500 int err;
501
502 spin_lock(&sl->lock);
503 if (sl->tty)
504 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
505
506 netif_stop_queue(dev);
507 sl->rcount = 0;
508 sl->xleft = 0;
509 err = lapb_unregister(dev);
510 if (err != LAPB_OK)
511 printk(KERN_ERR "x25_asy_close: lapb_unregister error -%d\n",
512 err);
513 spin_unlock(&sl->lock);
514 return 0;
515 }
516
517 /*
518 * Handle the 'receiver data ready' interrupt.
519 * This function is called by the 'tty_io' module in the kernel when
520 * a block of X.25 data has been received, which can now be decapsulated
521 * and sent on to some IP layer for further processing.
522 */
523
524 static void x25_asy_receive_buf(struct tty_struct *tty,
525 const unsigned char *cp, char *fp, int count)
526 {
527 struct x25_asy *sl = tty->disc_data;
528
529 if (!sl || sl->magic != X25_ASY_MAGIC || !netif_running(sl->dev))
530 return;
531
532
533 /* Read the characters out of the buffer */
534 while (count--) {
535 if (fp && *fp++) {
536 if (!test_and_set_bit(SLF_ERROR, &sl->flags))
537 sl->dev->stats.rx_errors++;
538 cp++;
539 continue;
540 }
541 x25_asy_unesc(sl, *cp++);
542 }
543 }
544
545 /*
546 * Open the high-level part of the X.25 channel.
547 * This function is called by the TTY module when the
548 * X.25 line discipline is called for. Because we are
549 * sure the tty line exists, we only have to link it to
550 * a free X.25 channel...
551 */
552
553 static int x25_asy_open_tty(struct tty_struct *tty)
554 {
555 struct x25_asy *sl = tty->disc_data;
556 int err;
557
558 if (tty->ops->write == NULL)
559 return -EOPNOTSUPP;
560
561 /* First make sure we're not already connected. */
562 if (sl && sl->magic == X25_ASY_MAGIC)
563 return -EEXIST;
564
565 /* OK. Find a free X.25 channel to use. */
566 sl = x25_asy_alloc();
567 if (sl == NULL)
568 return -ENFILE;
569
570 sl->tty = tty;
571 tty->disc_data = sl;
572 tty->receive_room = 65536;
573 tty_driver_flush_buffer(tty);
574 tty_ldisc_flush(tty);
575
576 /* Restore default settings */
577 sl->dev->type = ARPHRD_X25;
578
579 /* Perform the low-level X.25 async init */
580 err = x25_asy_open(sl->dev);
581 if (err)
582 return err;
583 /* Done. We have linked the TTY line to a channel. */
584 return sl->dev->base_addr;
585 }
586
587
588 /*
589 * Close down an X.25 channel.
590 * This means flushing out any pending queues, and then restoring the
591 * TTY line discipline to what it was before it got hooked to X.25
592 * (which usually is TTY again).
593 */
594 static void x25_asy_close_tty(struct tty_struct *tty)
595 {
596 struct x25_asy *sl = tty->disc_data;
597
598 /* First make sure we're connected. */
599 if (!sl || sl->magic != X25_ASY_MAGIC)
600 return;
601
602 rtnl_lock();
603 if (sl->dev->flags & IFF_UP)
604 dev_close(sl->dev);
605 rtnl_unlock();
606
607 tty->disc_data = NULL;
608 sl->tty = NULL;
609 x25_asy_free(sl);
610 }
611
612 /************************************************************************
613 * STANDARD X.25 ENCAPSULATION *
614 ************************************************************************/
615
616 static int x25_asy_esc(unsigned char *s, unsigned char *d, int len)
617 {
618 unsigned char *ptr = d;
619 unsigned char c;
620
621 /*
622 * Send an initial END character to flush out any
623 * data that may have accumulated in the receiver
624 * due to line noise.
625 */
626
627 *ptr++ = X25_END; /* Send 10111110 bit seq */
628
629 /*
630 * For each byte in the packet, send the appropriate
631 * character sequence, according to the X.25 protocol.
632 */
633
634 while (len-- > 0) {
635 switch (c = *s++) {
636 case X25_END:
637 *ptr++ = X25_ESC;
638 *ptr++ = X25_ESCAPE(X25_END);
639 break;
640 case X25_ESC:
641 *ptr++ = X25_ESC;
642 *ptr++ = X25_ESCAPE(X25_ESC);
643 break;
644 default:
645 *ptr++ = c;
646 break;
647 }
648 }
649 *ptr++ = X25_END;
650 return (ptr - d);
651 }
652
653 static void x25_asy_unesc(struct x25_asy *sl, unsigned char s)
654 {
655
656 switch (s) {
657 case X25_END:
658 if (!test_and_clear_bit(SLF_ERROR, &sl->flags)
659 && sl->rcount > 2)
660 x25_asy_bump(sl);
661 clear_bit(SLF_ESCAPE, &sl->flags);
662 sl->rcount = 0;
663 return;
664 case X25_ESC:
665 set_bit(SLF_ESCAPE, &sl->flags);
666 return;
667 case X25_ESCAPE(X25_ESC):
668 case X25_ESCAPE(X25_END):
669 if (test_and_clear_bit(SLF_ESCAPE, &sl->flags))
670 s = X25_UNESCAPE(s);
671 break;
672 }
673 if (!test_bit(SLF_ERROR, &sl->flags)) {
674 if (sl->rcount < sl->buffsize) {
675 sl->rbuff[sl->rcount++] = s;
676 return;
677 }
678 sl->dev->stats.rx_over_errors++;
679 set_bit(SLF_ERROR, &sl->flags);
680 }
681 }
682
683
684 /* Perform I/O control on an active X.25 channel. */
685 static int x25_asy_ioctl(struct tty_struct *tty, struct file *file,
686 unsigned int cmd, unsigned long arg)
687 {
688 struct x25_asy *sl = tty->disc_data;
689
690 /* First make sure we're connected. */
691 if (!sl || sl->magic != X25_ASY_MAGIC)
692 return -EINVAL;
693
694 switch (cmd) {
695 case SIOCGIFNAME:
696 if (copy_to_user((void __user *)arg, sl->dev->name,
697 strlen(sl->dev->name) + 1))
698 return -EFAULT;
699 return 0;
700 case SIOCSIFHWADDR:
701 return -EINVAL;
702 default:
703 return tty_mode_ioctl(tty, file, cmd, arg);
704 }
705 }
706
707 static int x25_asy_open_dev(struct net_device *dev)
708 {
709 struct x25_asy *sl = netdev_priv(dev);
710 if (sl->tty == NULL)
711 return -ENODEV;
712 return 0;
713 }
714
715 static const struct net_device_ops x25_asy_netdev_ops = {
716 .ndo_open = x25_asy_open_dev,
717 .ndo_stop = x25_asy_close,
718 .ndo_start_xmit = x25_asy_xmit,
719 .ndo_tx_timeout = x25_asy_timeout,
720 .ndo_change_mtu = x25_asy_change_mtu,
721 };
722
723 /* Initialise the X.25 driver. Called by the device init code */
724 static void x25_asy_setup(struct net_device *dev)
725 {
726 struct x25_asy *sl = netdev_priv(dev);
727
728 sl->magic = X25_ASY_MAGIC;
729 sl->dev = dev;
730 spin_lock_init(&sl->lock);
731 set_bit(SLF_INUSE, &sl->flags);
732
733 /*
734 * Finish setting up the DEVICE info.
735 */
736
737 dev->mtu = SL_MTU;
738 dev->netdev_ops = &x25_asy_netdev_ops;
739 dev->watchdog_timeo = HZ*20;
740 dev->hard_header_len = 0;
741 dev->addr_len = 0;
742 dev->type = ARPHRD_X25;
743 dev->tx_queue_len = 10;
744
745 /* New-style flags. */
746 dev->flags = IFF_NOARP;
747 }
748
749 static struct tty_ldisc_ops x25_ldisc = {
750 .owner = THIS_MODULE,
751 .magic = TTY_LDISC_MAGIC,
752 .name = "X.25",
753 .open = x25_asy_open_tty,
754 .close = x25_asy_close_tty,
755 .ioctl = x25_asy_ioctl,
756 .receive_buf = x25_asy_receive_buf,
757 .write_wakeup = x25_asy_write_wakeup,
758 };
759
760 static int __init init_x25_asy(void)
761 {
762 if (x25_asy_maxdev < 4)
763 x25_asy_maxdev = 4; /* Sanity */
764
765 printk(KERN_INFO "X.25 async: version 0.00 ALPHA "
766 "(dynamic channels, max=%d).\n", x25_asy_maxdev);
767
768 x25_asy_devs = kcalloc(x25_asy_maxdev, sizeof(struct net_device *),
769 GFP_KERNEL);
770 if (!x25_asy_devs) {
771 printk(KERN_WARNING "X25 async: Can't allocate x25_asy_ctrls[] "
772 "array! Uaargh! (-> No X.25 available)\n");
773 return -ENOMEM;
774 }
775
776 return tty_register_ldisc(N_X25, &x25_ldisc);
777 }
778
779
780 static void __exit exit_x25_asy(void)
781 {
782 struct net_device *dev;
783 int i;
784
785 for (i = 0; i < x25_asy_maxdev; i++) {
786 dev = x25_asy_devs[i];
787 if (dev) {
788 struct x25_asy *sl = netdev_priv(dev);
789
790 spin_lock_bh(&sl->lock);
791 if (sl->tty)
792 tty_hangup(sl->tty);
793
794 spin_unlock_bh(&sl->lock);
795 /*
796 * VSV = if dev->start==0, then device
797 * unregistered while close proc.
798 */
799 unregister_netdev(dev);
800 free_netdev(dev);
801 }
802 }
803
804 kfree(x25_asy_devs);
805 tty_unregister_ldisc(N_X25);
806 }
807
808 module_init(init_x25_asy);
809 module_exit(exit_x25_asy);
Linux kernel - Deliverables
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