xref: /linux/drivers/block/aoe/aoecmd.c (revision c537b994505099b7197e7d3125b942ecbcc51eb6)
1 /* Copyright (c) 2006 Coraid, Inc.  See COPYING for GPL terms. */
2 /*
3  * aoecmd.c
4  * Filesystem request handling methods
5  */
6 
7 #include <linux/hdreg.h>
8 #include <linux/blkdev.h>
9 #include <linux/skbuff.h>
10 #include <linux/netdevice.h>
11 #include <linux/genhd.h>
12 #include <asm/unaligned.h>
13 #include "aoe.h"
14 
15 #define TIMERTICK (HZ / 10)
16 #define MINTIMER (2 * TIMERTICK)
17 #define MAXTIMER (HZ << 1)
18 
19 static int aoe_deadsecs = 60 * 3;
20 module_param(aoe_deadsecs, int, 0644);
21 MODULE_PARM_DESC(aoe_deadsecs, "After aoe_deadsecs seconds, give up and fail dev.");
22 
23 struct sk_buff *
24 new_skb(ulong len)
25 {
26 	struct sk_buff *skb;
27 
28 	skb = alloc_skb(len, GFP_ATOMIC);
29 	if (skb) {
30 		skb->nh.raw = skb->mac.raw = skb->data;
31 		skb->protocol = __constant_htons(ETH_P_AOE);
32 		skb->priority = 0;
33 		skb->next = skb->prev = NULL;
34 
35 		/* tell the network layer not to perform IP checksums
36 		 * or to get the NIC to do it
37 		 */
38 		skb->ip_summed = CHECKSUM_NONE;
39 	}
40 	return skb;
41 }
42 
43 static struct frame *
44 getframe(struct aoedev *d, int tag)
45 {
46 	struct frame *f, *e;
47 
48 	f = d->frames;
49 	e = f + d->nframes;
50 	for (; f<e; f++)
51 		if (f->tag == tag)
52 			return f;
53 	return NULL;
54 }
55 
56 /*
57  * Leave the top bit clear so we have tagspace for userland.
58  * The bottom 16 bits are the xmit tick for rexmit/rttavg processing.
59  * This driver reserves tag -1 to mean "unused frame."
60  */
61 static int
62 newtag(struct aoedev *d)
63 {
64 	register ulong n;
65 
66 	n = jiffies & 0xffff;
67 	return n |= (++d->lasttag & 0x7fff) << 16;
68 }
69 
70 static int
71 aoehdr_atainit(struct aoedev *d, struct aoe_hdr *h)
72 {
73 	u32 host_tag = newtag(d);
74 
75 	memcpy(h->src, d->ifp->dev_addr, sizeof h->src);
76 	memcpy(h->dst, d->addr, sizeof h->dst);
77 	h->type = __constant_cpu_to_be16(ETH_P_AOE);
78 	h->verfl = AOE_HVER;
79 	h->major = cpu_to_be16(d->aoemajor);
80 	h->minor = d->aoeminor;
81 	h->cmd = AOECMD_ATA;
82 	h->tag = cpu_to_be32(host_tag);
83 
84 	return host_tag;
85 }
86 
87 static inline void
88 put_lba(struct aoe_atahdr *ah, sector_t lba)
89 {
90 	ah->lba0 = lba;
91 	ah->lba1 = lba >>= 8;
92 	ah->lba2 = lba >>= 8;
93 	ah->lba3 = lba >>= 8;
94 	ah->lba4 = lba >>= 8;
95 	ah->lba5 = lba >>= 8;
96 }
97 
98 static void
99 aoecmd_ata_rw(struct aoedev *d, struct frame *f)
100 {
101 	struct aoe_hdr *h;
102 	struct aoe_atahdr *ah;
103 	struct buf *buf;
104 	struct sk_buff *skb;
105 	ulong bcnt;
106 	register sector_t sector;
107 	char writebit, extbit;
108 
109 	writebit = 0x10;
110 	extbit = 0x4;
111 
112 	buf = d->inprocess;
113 
114 	sector = buf->sector;
115 	bcnt = buf->bv_resid;
116 	if (bcnt > d->maxbcnt)
117 		bcnt = d->maxbcnt;
118 
119 	/* initialize the headers & frame */
120 	skb = f->skb;
121 	h = (struct aoe_hdr *) skb->mac.raw;
122 	ah = (struct aoe_atahdr *) (h+1);
123 	skb_put(skb, sizeof *h + sizeof *ah);
124 	memset(h, 0, skb->len);
125 	f->tag = aoehdr_atainit(d, h);
126 	f->waited = 0;
127 	f->buf = buf;
128 	f->bufaddr = buf->bufaddr;
129 	f->bcnt = bcnt;
130 	f->lba = sector;
131 
132 	/* set up ata header */
133 	ah->scnt = bcnt >> 9;
134 	put_lba(ah, sector);
135 	if (d->flags & DEVFL_EXT) {
136 		ah->aflags |= AOEAFL_EXT;
137 	} else {
138 		extbit = 0;
139 		ah->lba3 &= 0x0f;
140 		ah->lba3 |= 0xe0;	/* LBA bit + obsolete 0xa0 */
141 	}
142 
143 	if (bio_data_dir(buf->bio) == WRITE) {
144 		skb_fill_page_desc(skb, 0, virt_to_page(f->bufaddr),
145 			offset_in_page(f->bufaddr), bcnt);
146 		ah->aflags |= AOEAFL_WRITE;
147 		skb->len += bcnt;
148 		skb->data_len = bcnt;
149 	} else {
150 		writebit = 0;
151 	}
152 
153 	ah->cmdstat = WIN_READ | writebit | extbit;
154 
155 	/* mark all tracking fields and load out */
156 	buf->nframesout += 1;
157 	buf->bufaddr += bcnt;
158 	buf->bv_resid -= bcnt;
159 /* printk(KERN_DEBUG "aoe: bv_resid=%ld\n", buf->bv_resid); */
160 	buf->resid -= bcnt;
161 	buf->sector += bcnt >> 9;
162 	if (buf->resid == 0) {
163 		d->inprocess = NULL;
164 	} else if (buf->bv_resid == 0) {
165 		buf->bv++;
166 		WARN_ON(buf->bv->bv_len == 0);
167 		buf->bv_resid = buf->bv->bv_len;
168 		buf->bufaddr = page_address(buf->bv->bv_page) + buf->bv->bv_offset;
169 	}
170 
171 	skb->dev = d->ifp;
172 	skb = skb_clone(skb, GFP_ATOMIC);
173 	if (skb == NULL)
174 		return;
175 	if (d->sendq_hd)
176 		d->sendq_tl->next = skb;
177 	else
178 		d->sendq_hd = skb;
179 	d->sendq_tl = skb;
180 }
181 
182 /* some callers cannot sleep, and they can call this function,
183  * transmitting the packets later, when interrupts are on
184  */
185 static struct sk_buff *
186 aoecmd_cfg_pkts(ushort aoemajor, unsigned char aoeminor, struct sk_buff **tail)
187 {
188 	struct aoe_hdr *h;
189 	struct aoe_cfghdr *ch;
190 	struct sk_buff *skb, *sl, *sl_tail;
191 	struct net_device *ifp;
192 
193 	sl = sl_tail = NULL;
194 
195 	read_lock(&dev_base_lock);
196 	for (ifp = dev_base; ifp; dev_put(ifp), ifp = ifp->next) {
197 		dev_hold(ifp);
198 		if (!is_aoe_netif(ifp))
199 			continue;
200 
201 		skb = new_skb(sizeof *h + sizeof *ch);
202 		if (skb == NULL) {
203 			printk(KERN_INFO "aoe: skb alloc failure\n");
204 			continue;
205 		}
206 		skb_put(skb, sizeof *h + sizeof *ch);
207 		skb->dev = ifp;
208 		if (sl_tail == NULL)
209 			sl_tail = skb;
210 		h = (struct aoe_hdr *) skb->mac.raw;
211 		memset(h, 0, sizeof *h + sizeof *ch);
212 
213 		memset(h->dst, 0xff, sizeof h->dst);
214 		memcpy(h->src, ifp->dev_addr, sizeof h->src);
215 		h->type = __constant_cpu_to_be16(ETH_P_AOE);
216 		h->verfl = AOE_HVER;
217 		h->major = cpu_to_be16(aoemajor);
218 		h->minor = aoeminor;
219 		h->cmd = AOECMD_CFG;
220 
221 		skb->next = sl;
222 		sl = skb;
223 	}
224 	read_unlock(&dev_base_lock);
225 
226 	if (tail != NULL)
227 		*tail = sl_tail;
228 	return sl;
229 }
230 
231 static struct frame *
232 freeframe(struct aoedev *d)
233 {
234 	struct frame *f, *e;
235 	int n = 0;
236 
237 	f = d->frames;
238 	e = f + d->nframes;
239 	for (; f<e; f++) {
240 		if (f->tag != FREETAG)
241 			continue;
242 		if (atomic_read(&skb_shinfo(f->skb)->dataref) == 1) {
243 			skb_shinfo(f->skb)->nr_frags = f->skb->data_len = 0;
244 			skb_trim(f->skb, 0);
245 			return f;
246 		}
247 		n++;
248 	}
249 	if (n == d->nframes)	/* wait for network layer */
250 		d->flags |= DEVFL_KICKME;
251 
252 	return NULL;
253 }
254 
255 /* enters with d->lock held */
256 void
257 aoecmd_work(struct aoedev *d)
258 {
259 	struct frame *f;
260 	struct buf *buf;
261 
262 	if (d->flags & DEVFL_PAUSE) {
263 		if (!aoedev_isbusy(d))
264 			d->sendq_hd = aoecmd_cfg_pkts(d->aoemajor,
265 						d->aoeminor, &d->sendq_tl);
266 		return;
267 	}
268 
269 loop:
270 	f = freeframe(d);
271 	if (f == NULL)
272 		return;
273 	if (d->inprocess == NULL) {
274 		if (list_empty(&d->bufq))
275 			return;
276 		buf = container_of(d->bufq.next, struct buf, bufs);
277 		list_del(d->bufq.next);
278 /*printk(KERN_DEBUG "aoe: bi_size=%ld\n", buf->bio->bi_size); */
279 		d->inprocess = buf;
280 	}
281 	aoecmd_ata_rw(d, f);
282 	goto loop;
283 }
284 
285 static void
286 rexmit(struct aoedev *d, struct frame *f)
287 {
288 	struct sk_buff *skb;
289 	struct aoe_hdr *h;
290 	struct aoe_atahdr *ah;
291 	char buf[128];
292 	u32 n;
293 
294 	n = newtag(d);
295 
296 	snprintf(buf, sizeof buf,
297 		"%15s e%ld.%ld oldtag=%08x@%08lx newtag=%08x\n",
298 		"retransmit",
299 		d->aoemajor, d->aoeminor, f->tag, jiffies, n);
300 	aoechr_error(buf);
301 
302 	skb = f->skb;
303 	h = (struct aoe_hdr *) skb->mac.raw;
304 	ah = (struct aoe_atahdr *) (h+1);
305 	f->tag = n;
306 	h->tag = cpu_to_be32(n);
307 	memcpy(h->dst, d->addr, sizeof h->dst);
308 	memcpy(h->src, d->ifp->dev_addr, sizeof h->src);
309 
310 	n = DEFAULTBCNT / 512;
311 	if (ah->scnt > n) {
312 		ah->scnt = n;
313 		if (ah->aflags & AOEAFL_WRITE) {
314 			skb_fill_page_desc(skb, 0, virt_to_page(f->bufaddr),
315 				offset_in_page(f->bufaddr), DEFAULTBCNT);
316 			skb->len = sizeof *h + sizeof *ah + DEFAULTBCNT;
317 			skb->data_len = DEFAULTBCNT;
318 		}
319 		if (++d->lostjumbo > (d->nframes << 1))
320 		if (d->maxbcnt != DEFAULTBCNT) {
321 			printk(KERN_INFO "aoe: e%ld.%ld: too many lost jumbo on %s - using 1KB frames.\n",
322 				d->aoemajor, d->aoeminor, d->ifp->name);
323 			d->maxbcnt = DEFAULTBCNT;
324 			d->flags |= DEVFL_MAXBCNT;
325 		}
326 	}
327 
328 	skb->dev = d->ifp;
329 	skb = skb_clone(skb, GFP_ATOMIC);
330 	if (skb == NULL)
331 		return;
332 	if (d->sendq_hd)
333 		d->sendq_tl->next = skb;
334 	else
335 		d->sendq_hd = skb;
336 	d->sendq_tl = skb;
337 }
338 
339 static int
340 tsince(int tag)
341 {
342 	int n;
343 
344 	n = jiffies & 0xffff;
345 	n -= tag & 0xffff;
346 	if (n < 0)
347 		n += 1<<16;
348 	return n;
349 }
350 
351 static void
352 rexmit_timer(ulong vp)
353 {
354 	struct aoedev *d;
355 	struct frame *f, *e;
356 	struct sk_buff *sl;
357 	register long timeout;
358 	ulong flags, n;
359 
360 	d = (struct aoedev *) vp;
361 	sl = NULL;
362 
363 	/* timeout is always ~150% of the moving average */
364 	timeout = d->rttavg;
365 	timeout += timeout >> 1;
366 
367 	spin_lock_irqsave(&d->lock, flags);
368 
369 	if (d->flags & DEVFL_TKILL) {
370 		spin_unlock_irqrestore(&d->lock, flags);
371 		return;
372 	}
373 	f = d->frames;
374 	e = f + d->nframes;
375 	for (; f<e; f++) {
376 		if (f->tag != FREETAG && tsince(f->tag) >= timeout) {
377 			n = f->waited += timeout;
378 			n /= HZ;
379 			if (n > aoe_deadsecs) { /* waited too long for response */
380 				aoedev_downdev(d);
381 				break;
382 			}
383 			rexmit(d, f);
384 		}
385 	}
386 	if (d->flags & DEVFL_KICKME) {
387 		d->flags &= ~DEVFL_KICKME;
388 		aoecmd_work(d);
389 	}
390 
391 	sl = d->sendq_hd;
392 	d->sendq_hd = d->sendq_tl = NULL;
393 	if (sl) {
394 		n = d->rttavg <<= 1;
395 		if (n > MAXTIMER)
396 			d->rttavg = MAXTIMER;
397 	}
398 
399 	d->timer.expires = jiffies + TIMERTICK;
400 	add_timer(&d->timer);
401 
402 	spin_unlock_irqrestore(&d->lock, flags);
403 
404 	aoenet_xmit(sl);
405 }
406 
407 /* this function performs work that has been deferred until sleeping is OK
408  */
409 void
410 aoecmd_sleepwork(struct work_struct *work)
411 {
412 	struct aoedev *d = container_of(work, struct aoedev, work);
413 
414 	if (d->flags & DEVFL_GDALLOC)
415 		aoeblk_gdalloc(d);
416 
417 	if (d->flags & DEVFL_NEWSIZE) {
418 		struct block_device *bd;
419 		unsigned long flags;
420 		u64 ssize;
421 
422 		ssize = d->gd->capacity;
423 		bd = bdget_disk(d->gd, 0);
424 
425 		if (bd) {
426 			mutex_lock(&bd->bd_inode->i_mutex);
427 			i_size_write(bd->bd_inode, (loff_t)ssize<<9);
428 			mutex_unlock(&bd->bd_inode->i_mutex);
429 			bdput(bd);
430 		}
431 		spin_lock_irqsave(&d->lock, flags);
432 		d->flags |= DEVFL_UP;
433 		d->flags &= ~DEVFL_NEWSIZE;
434 		spin_unlock_irqrestore(&d->lock, flags);
435 	}
436 }
437 
438 static void
439 ataid_complete(struct aoedev *d, unsigned char *id)
440 {
441 	u64 ssize;
442 	u16 n;
443 
444 	/* word 83: command set supported */
445 	n = le16_to_cpu(get_unaligned((__le16 *) &id[83<<1]));
446 
447 	/* word 86: command set/feature enabled */
448 	n |= le16_to_cpu(get_unaligned((__le16 *) &id[86<<1]));
449 
450 	if (n & (1<<10)) {	/* bit 10: LBA 48 */
451 		d->flags |= DEVFL_EXT;
452 
453 		/* word 100: number lba48 sectors */
454 		ssize = le64_to_cpu(get_unaligned((__le64 *) &id[100<<1]));
455 
456 		/* set as in ide-disk.c:init_idedisk_capacity */
457 		d->geo.cylinders = ssize;
458 		d->geo.cylinders /= (255 * 63);
459 		d->geo.heads = 255;
460 		d->geo.sectors = 63;
461 	} else {
462 		d->flags &= ~DEVFL_EXT;
463 
464 		/* number lba28 sectors */
465 		ssize = le32_to_cpu(get_unaligned((__le32 *) &id[60<<1]));
466 
467 		/* NOTE: obsolete in ATA 6 */
468 		d->geo.cylinders = le16_to_cpu(get_unaligned((__le16 *) &id[54<<1]));
469 		d->geo.heads = le16_to_cpu(get_unaligned((__le16 *) &id[55<<1]));
470 		d->geo.sectors = le16_to_cpu(get_unaligned((__le16 *) &id[56<<1]));
471 	}
472 
473 	if (d->ssize != ssize)
474 		printk(KERN_INFO "aoe: %012llx e%lu.%lu v%04x has %llu sectors\n",
475 			(unsigned long long)mac_addr(d->addr),
476 			d->aoemajor, d->aoeminor,
477 			d->fw_ver, (long long)ssize);
478 	d->ssize = ssize;
479 	d->geo.start = 0;
480 	if (d->gd != NULL) {
481 		d->gd->capacity = ssize;
482 		d->flags |= DEVFL_NEWSIZE;
483 	} else {
484 		if (d->flags & DEVFL_GDALLOC) {
485 			printk(KERN_ERR "aoe: can't schedule work for e%lu.%lu, %s\n",
486 			       d->aoemajor, d->aoeminor,
487 			       "it's already on!  This shouldn't happen.\n");
488 			return;
489 		}
490 		d->flags |= DEVFL_GDALLOC;
491 	}
492 	schedule_work(&d->work);
493 }
494 
495 static void
496 calc_rttavg(struct aoedev *d, int rtt)
497 {
498 	register long n;
499 
500 	n = rtt;
501 	if (n < 0) {
502 		n = -rtt;
503 		if (n < MINTIMER)
504 			n = MINTIMER;
505 		else if (n > MAXTIMER)
506 			n = MAXTIMER;
507 		d->mintimer += (n - d->mintimer) >> 1;
508 	} else if (n < d->mintimer)
509 		n = d->mintimer;
510 	else if (n > MAXTIMER)
511 		n = MAXTIMER;
512 
513 	/* g == .25; cf. Congestion Avoidance and Control, Jacobson & Karels; 1988 */
514 	n -= d->rttavg;
515 	d->rttavg += n >> 2;
516 }
517 
518 void
519 aoecmd_ata_rsp(struct sk_buff *skb)
520 {
521 	struct aoedev *d;
522 	struct aoe_hdr *hin, *hout;
523 	struct aoe_atahdr *ahin, *ahout;
524 	struct frame *f;
525 	struct buf *buf;
526 	struct sk_buff *sl;
527 	register long n;
528 	ulong flags;
529 	char ebuf[128];
530 	u16 aoemajor;
531 
532 	hin = (struct aoe_hdr *) skb->mac.raw;
533 	aoemajor = be16_to_cpu(get_unaligned(&hin->major));
534 	d = aoedev_by_aoeaddr(aoemajor, hin->minor);
535 	if (d == NULL) {
536 		snprintf(ebuf, sizeof ebuf, "aoecmd_ata_rsp: ata response "
537 			"for unknown device %d.%d\n",
538 			 aoemajor, hin->minor);
539 		aoechr_error(ebuf);
540 		return;
541 	}
542 
543 	spin_lock_irqsave(&d->lock, flags);
544 
545 	n = be32_to_cpu(get_unaligned(&hin->tag));
546 	f = getframe(d, n);
547 	if (f == NULL) {
548 		calc_rttavg(d, -tsince(n));
549 		spin_unlock_irqrestore(&d->lock, flags);
550 		snprintf(ebuf, sizeof ebuf,
551 			"%15s e%d.%d    tag=%08x@%08lx\n",
552 			"unexpected rsp",
553 			be16_to_cpu(get_unaligned(&hin->major)),
554 			hin->minor,
555 			be32_to_cpu(get_unaligned(&hin->tag)),
556 			jiffies);
557 		aoechr_error(ebuf);
558 		return;
559 	}
560 
561 	calc_rttavg(d, tsince(f->tag));
562 
563 	ahin = (struct aoe_atahdr *) (hin+1);
564 	hout = (struct aoe_hdr *) f->skb->mac.raw;
565 	ahout = (struct aoe_atahdr *) (hout+1);
566 	buf = f->buf;
567 
568 	if (ahout->cmdstat == WIN_IDENTIFY)
569 		d->flags &= ~DEVFL_PAUSE;
570 	if (ahin->cmdstat & 0xa9) {	/* these bits cleared on success */
571 		printk(KERN_ERR
572 			"aoe: ata error cmd=%2.2Xh stat=%2.2Xh from e%ld.%ld\n",
573 			ahout->cmdstat, ahin->cmdstat,
574 			d->aoemajor, d->aoeminor);
575 		if (buf)
576 			buf->flags |= BUFFL_FAIL;
577 	} else {
578 		n = ahout->scnt << 9;
579 		switch (ahout->cmdstat) {
580 		case WIN_READ:
581 		case WIN_READ_EXT:
582 			if (skb->len - sizeof *hin - sizeof *ahin < n) {
583 				printk(KERN_ERR
584 					"aoe: runt data size in read.  skb->len=%d\n",
585 					skb->len);
586 				/* fail frame f?  just returning will rexmit. */
587 				spin_unlock_irqrestore(&d->lock, flags);
588 				return;
589 			}
590 			memcpy(f->bufaddr, ahin+1, n);
591 		case WIN_WRITE:
592 		case WIN_WRITE_EXT:
593 			if (f->bcnt -= n) {
594 				skb = f->skb;
595 				f->bufaddr += n;
596 				put_lba(ahout, f->lba += ahout->scnt);
597 				n = f->bcnt;
598 				if (n > DEFAULTBCNT)
599 					n = DEFAULTBCNT;
600 				ahout->scnt = n >> 9;
601 				if (ahout->aflags & AOEAFL_WRITE) {
602 					skb_fill_page_desc(skb, 0,
603 						virt_to_page(f->bufaddr),
604 						offset_in_page(f->bufaddr), n);
605 					skb->len = sizeof *hout + sizeof *ahout + n;
606 					skb->data_len = n;
607 				}
608 				f->tag = newtag(d);
609 				hout->tag = cpu_to_be32(f->tag);
610 				skb->dev = d->ifp;
611 				skb = skb_clone(skb, GFP_ATOMIC);
612 				spin_unlock_irqrestore(&d->lock, flags);
613 				if (skb)
614 					aoenet_xmit(skb);
615 				return;
616 			}
617 			if (n > DEFAULTBCNT)
618 				d->lostjumbo = 0;
619 			break;
620 		case WIN_IDENTIFY:
621 			if (skb->len - sizeof *hin - sizeof *ahin < 512) {
622 				printk(KERN_INFO
623 					"aoe: runt data size in ataid.  skb->len=%d\n",
624 					skb->len);
625 				spin_unlock_irqrestore(&d->lock, flags);
626 				return;
627 			}
628 			ataid_complete(d, (char *) (ahin+1));
629 			break;
630 		default:
631 			printk(KERN_INFO
632 				"aoe: unrecognized ata command %2.2Xh for %d.%d\n",
633 				ahout->cmdstat,
634 				be16_to_cpu(get_unaligned(&hin->major)),
635 				hin->minor);
636 		}
637 	}
638 
639 	if (buf) {
640 		buf->nframesout -= 1;
641 		if (buf->nframesout == 0 && buf->resid == 0) {
642 			unsigned long duration = jiffies - buf->start_time;
643 			unsigned long n_sect = buf->bio->bi_size >> 9;
644 			struct gendisk *disk = d->gd;
645 			const int rw = bio_data_dir(buf->bio);
646 
647 			disk_stat_inc(disk, ios[rw]);
648 			disk_stat_add(disk, ticks[rw], duration);
649 			disk_stat_add(disk, sectors[rw], n_sect);
650 			disk_stat_add(disk, io_ticks, duration);
651 			n = (buf->flags & BUFFL_FAIL) ? -EIO : 0;
652 			bio_endio(buf->bio, buf->bio->bi_size, n);
653 			mempool_free(buf, d->bufpool);
654 		}
655 	}
656 
657 	f->buf = NULL;
658 	f->tag = FREETAG;
659 
660 	aoecmd_work(d);
661 	sl = d->sendq_hd;
662 	d->sendq_hd = d->sendq_tl = NULL;
663 
664 	spin_unlock_irqrestore(&d->lock, flags);
665 	aoenet_xmit(sl);
666 }
667 
668 void
669 aoecmd_cfg(ushort aoemajor, unsigned char aoeminor)
670 {
671 	struct sk_buff *sl;
672 
673 	sl = aoecmd_cfg_pkts(aoemajor, aoeminor, NULL);
674 
675 	aoenet_xmit(sl);
676 }
677 
678 /*
679  * Since we only call this in one place (and it only prepares one frame)
680  * we just return the skb.  Usually we'd chain it up to the aoedev sendq.
681  */
682 static struct sk_buff *
683 aoecmd_ata_id(struct aoedev *d)
684 {
685 	struct aoe_hdr *h;
686 	struct aoe_atahdr *ah;
687 	struct frame *f;
688 	struct sk_buff *skb;
689 
690 	f = freeframe(d);
691 	if (f == NULL) {
692 		printk(KERN_ERR "aoe: can't get a frame. This shouldn't happen.\n");
693 		return NULL;
694 	}
695 
696 	/* initialize the headers & frame */
697 	skb = f->skb;
698 	h = (struct aoe_hdr *) skb->mac.raw;
699 	ah = (struct aoe_atahdr *) (h+1);
700 	skb_put(skb, sizeof *h + sizeof *ah);
701 	memset(h, 0, skb->len);
702 	f->tag = aoehdr_atainit(d, h);
703 	f->waited = 0;
704 
705 	/* set up ata header */
706 	ah->scnt = 1;
707 	ah->cmdstat = WIN_IDENTIFY;
708 	ah->lba3 = 0xa0;
709 
710 	skb->dev = d->ifp;
711 
712 	d->rttavg = MAXTIMER;
713 	d->timer.function = rexmit_timer;
714 
715 	return skb_clone(skb, GFP_ATOMIC);
716 }
717 
718 void
719 aoecmd_cfg_rsp(struct sk_buff *skb)
720 {
721 	struct aoedev *d;
722 	struct aoe_hdr *h;
723 	struct aoe_cfghdr *ch;
724 	ulong flags, sysminor, aoemajor;
725 	struct sk_buff *sl;
726 	enum { MAXFRAMES = 16 };
727 	u16 n;
728 
729 	h = (struct aoe_hdr *) skb->mac.raw;
730 	ch = (struct aoe_cfghdr *) (h+1);
731 
732 	/*
733 	 * Enough people have their dip switches set backwards to
734 	 * warrant a loud message for this special case.
735 	 */
736 	aoemajor = be16_to_cpu(get_unaligned(&h->major));
737 	if (aoemajor == 0xfff) {
738 		printk(KERN_ERR "aoe: Warning: shelf address is all ones.  "
739 			"Check shelf dip switches.\n");
740 		return;
741 	}
742 
743 	sysminor = SYSMINOR(aoemajor, h->minor);
744 	if (sysminor * AOE_PARTITIONS + AOE_PARTITIONS > MINORMASK) {
745 		printk(KERN_INFO "aoe: e%ld.%d: minor number too large\n",
746 			aoemajor, (int) h->minor);
747 		return;
748 	}
749 
750 	n = be16_to_cpu(ch->bufcnt);
751 	if (n > MAXFRAMES)	/* keep it reasonable */
752 		n = MAXFRAMES;
753 
754 	d = aoedev_by_sysminor_m(sysminor, n);
755 	if (d == NULL) {
756 		printk(KERN_INFO "aoe: device sysminor_m failure\n");
757 		return;
758 	}
759 
760 	spin_lock_irqsave(&d->lock, flags);
761 
762 	/* permit device to migrate mac and network interface */
763 	d->ifp = skb->dev;
764 	memcpy(d->addr, h->src, sizeof d->addr);
765 	if (!(d->flags & DEVFL_MAXBCNT)) {
766 		n = d->ifp->mtu;
767 		n -= sizeof (struct aoe_hdr) + sizeof (struct aoe_atahdr);
768 		n /= 512;
769 		if (n > ch->scnt)
770 			n = ch->scnt;
771 		n = n ? n * 512 : DEFAULTBCNT;
772 		if (n != d->maxbcnt) {
773 			printk(KERN_INFO
774 				"aoe: e%ld.%ld: setting %d byte data frames on %s\n",
775 				d->aoemajor, d->aoeminor, n, d->ifp->name);
776 			d->maxbcnt = n;
777 		}
778 	}
779 
780 	/* don't change users' perspective */
781 	if (d->nopen && !(d->flags & DEVFL_PAUSE)) {
782 		spin_unlock_irqrestore(&d->lock, flags);
783 		return;
784 	}
785 	d->flags |= DEVFL_PAUSE;	/* force pause */
786 	d->mintimer = MINTIMER;
787 	d->fw_ver = be16_to_cpu(ch->fwver);
788 
789 	/* check for already outstanding ataid */
790 	sl = aoedev_isbusy(d) == 0 ? aoecmd_ata_id(d) : NULL;
791 
792 	spin_unlock_irqrestore(&d->lock, flags);
793 
794 	aoenet_xmit(sl);
795 }
796 
797