xref: /openbmc/linux/drivers/block/aoe/aoecmd.c (revision 64c70b1c)
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_reset_mac_header(skb);
31 		skb_reset_network_header(skb);
32 		skb->protocol = __constant_htons(ETH_P_AOE);
33 		skb->priority = 0;
34 		skb->next = skb->prev = NULL;
35 
36 		/* tell the network layer not to perform IP checksums
37 		 * or to get the NIC to do it
38 		 */
39 		skb->ip_summed = CHECKSUM_NONE;
40 	}
41 	return skb;
42 }
43 
44 static struct frame *
45 getframe(struct aoedev *d, int tag)
46 {
47 	struct frame *f, *e;
48 
49 	f = d->frames;
50 	e = f + d->nframes;
51 	for (; f<e; f++)
52 		if (f->tag == tag)
53 			return f;
54 	return NULL;
55 }
56 
57 /*
58  * Leave the top bit clear so we have tagspace for userland.
59  * The bottom 16 bits are the xmit tick for rexmit/rttavg processing.
60  * This driver reserves tag -1 to mean "unused frame."
61  */
62 static int
63 newtag(struct aoedev *d)
64 {
65 	register ulong n;
66 
67 	n = jiffies & 0xffff;
68 	return n |= (++d->lasttag & 0x7fff) << 16;
69 }
70 
71 static int
72 aoehdr_atainit(struct aoedev *d, struct aoe_hdr *h)
73 {
74 	u32 host_tag = newtag(d);
75 
76 	memcpy(h->src, d->ifp->dev_addr, sizeof h->src);
77 	memcpy(h->dst, d->addr, sizeof h->dst);
78 	h->type = __constant_cpu_to_be16(ETH_P_AOE);
79 	h->verfl = AOE_HVER;
80 	h->major = cpu_to_be16(d->aoemajor);
81 	h->minor = d->aoeminor;
82 	h->cmd = AOECMD_ATA;
83 	h->tag = cpu_to_be32(host_tag);
84 
85 	return host_tag;
86 }
87 
88 static inline void
89 put_lba(struct aoe_atahdr *ah, sector_t lba)
90 {
91 	ah->lba0 = lba;
92 	ah->lba1 = lba >>= 8;
93 	ah->lba2 = lba >>= 8;
94 	ah->lba3 = lba >>= 8;
95 	ah->lba4 = lba >>= 8;
96 	ah->lba5 = lba >>= 8;
97 }
98 
99 static void
100 aoecmd_ata_rw(struct aoedev *d, struct frame *f)
101 {
102 	struct aoe_hdr *h;
103 	struct aoe_atahdr *ah;
104 	struct buf *buf;
105 	struct sk_buff *skb;
106 	ulong bcnt;
107 	register sector_t sector;
108 	char writebit, extbit;
109 
110 	writebit = 0x10;
111 	extbit = 0x4;
112 
113 	buf = d->inprocess;
114 
115 	sector = buf->sector;
116 	bcnt = buf->bv_resid;
117 	if (bcnt > d->maxbcnt)
118 		bcnt = d->maxbcnt;
119 
120 	/* initialize the headers & frame */
121 	skb = f->skb;
122 	h = aoe_hdr(skb);
123 	ah = (struct aoe_atahdr *) (h+1);
124 	skb_put(skb, sizeof *h + sizeof *ah);
125 	memset(h, 0, skb->len);
126 	f->tag = aoehdr_atainit(d, h);
127 	f->waited = 0;
128 	f->buf = buf;
129 	f->bufaddr = buf->bufaddr;
130 	f->bcnt = bcnt;
131 	f->lba = sector;
132 
133 	/* set up ata header */
134 	ah->scnt = bcnt >> 9;
135 	put_lba(ah, sector);
136 	if (d->flags & DEVFL_EXT) {
137 		ah->aflags |= AOEAFL_EXT;
138 	} else {
139 		extbit = 0;
140 		ah->lba3 &= 0x0f;
141 		ah->lba3 |= 0xe0;	/* LBA bit + obsolete 0xa0 */
142 	}
143 
144 	if (bio_data_dir(buf->bio) == WRITE) {
145 		skb_fill_page_desc(skb, 0, virt_to_page(f->bufaddr),
146 			offset_in_page(f->bufaddr), bcnt);
147 		ah->aflags |= AOEAFL_WRITE;
148 		skb->len += bcnt;
149 		skb->data_len = bcnt;
150 	} else {
151 		writebit = 0;
152 	}
153 
154 	ah->cmdstat = WIN_READ | writebit | extbit;
155 
156 	/* mark all tracking fields and load out */
157 	buf->nframesout += 1;
158 	buf->bufaddr += bcnt;
159 	buf->bv_resid -= bcnt;
160 /* printk(KERN_DEBUG "aoe: bv_resid=%ld\n", buf->bv_resid); */
161 	buf->resid -= bcnt;
162 	buf->sector += bcnt >> 9;
163 	if (buf->resid == 0) {
164 		d->inprocess = NULL;
165 	} else if (buf->bv_resid == 0) {
166 		buf->bv++;
167 		WARN_ON(buf->bv->bv_len == 0);
168 		buf->bv_resid = buf->bv->bv_len;
169 		buf->bufaddr = page_address(buf->bv->bv_page) + buf->bv->bv_offset;
170 	}
171 
172 	skb->dev = d->ifp;
173 	skb = skb_clone(skb, GFP_ATOMIC);
174 	if (skb == NULL)
175 		return;
176 	if (d->sendq_hd)
177 		d->sendq_tl->next = skb;
178 	else
179 		d->sendq_hd = skb;
180 	d->sendq_tl = skb;
181 }
182 
183 /* some callers cannot sleep, and they can call this function,
184  * transmitting the packets later, when interrupts are on
185  */
186 static struct sk_buff *
187 aoecmd_cfg_pkts(ushort aoemajor, unsigned char aoeminor, struct sk_buff **tail)
188 {
189 	struct aoe_hdr *h;
190 	struct aoe_cfghdr *ch;
191 	struct sk_buff *skb, *sl, *sl_tail;
192 	struct net_device *ifp;
193 
194 	sl = sl_tail = NULL;
195 
196 	read_lock(&dev_base_lock);
197 	for_each_netdev(ifp) {
198 		dev_hold(ifp);
199 		if (!is_aoe_netif(ifp))
200 			goto cont;
201 
202 		skb = new_skb(sizeof *h + sizeof *ch);
203 		if (skb == NULL) {
204 			printk(KERN_INFO "aoe: skb alloc failure\n");
205 			goto cont;
206 		}
207 		skb_put(skb, sizeof *h + sizeof *ch);
208 		skb->dev = ifp;
209 		if (sl_tail == NULL)
210 			sl_tail = skb;
211 		h = aoe_hdr(skb);
212 		memset(h, 0, sizeof *h + sizeof *ch);
213 
214 		memset(h->dst, 0xff, sizeof h->dst);
215 		memcpy(h->src, ifp->dev_addr, sizeof h->src);
216 		h->type = __constant_cpu_to_be16(ETH_P_AOE);
217 		h->verfl = AOE_HVER;
218 		h->major = cpu_to_be16(aoemajor);
219 		h->minor = aoeminor;
220 		h->cmd = AOECMD_CFG;
221 
222 		skb->next = sl;
223 		sl = skb;
224 cont:
225 		dev_put(ifp);
226 	}
227 	read_unlock(&dev_base_lock);
228 
229 	if (tail != NULL)
230 		*tail = sl_tail;
231 	return sl;
232 }
233 
234 static struct frame *
235 freeframe(struct aoedev *d)
236 {
237 	struct frame *f, *e;
238 	int n = 0;
239 
240 	f = d->frames;
241 	e = f + d->nframes;
242 	for (; f<e; f++) {
243 		if (f->tag != FREETAG)
244 			continue;
245 		if (atomic_read(&skb_shinfo(f->skb)->dataref) == 1) {
246 			skb_shinfo(f->skb)->nr_frags = f->skb->data_len = 0;
247 			skb_trim(f->skb, 0);
248 			return f;
249 		}
250 		n++;
251 	}
252 	if (n == d->nframes)	/* wait for network layer */
253 		d->flags |= DEVFL_KICKME;
254 
255 	return NULL;
256 }
257 
258 /* enters with d->lock held */
259 void
260 aoecmd_work(struct aoedev *d)
261 {
262 	struct frame *f;
263 	struct buf *buf;
264 
265 	if (d->flags & DEVFL_PAUSE) {
266 		if (!aoedev_isbusy(d))
267 			d->sendq_hd = aoecmd_cfg_pkts(d->aoemajor,
268 						d->aoeminor, &d->sendq_tl);
269 		return;
270 	}
271 
272 loop:
273 	f = freeframe(d);
274 	if (f == NULL)
275 		return;
276 	if (d->inprocess == NULL) {
277 		if (list_empty(&d->bufq))
278 			return;
279 		buf = container_of(d->bufq.next, struct buf, bufs);
280 		list_del(d->bufq.next);
281 /*printk(KERN_DEBUG "aoe: bi_size=%ld\n", buf->bio->bi_size); */
282 		d->inprocess = buf;
283 	}
284 	aoecmd_ata_rw(d, f);
285 	goto loop;
286 }
287 
288 static void
289 rexmit(struct aoedev *d, struct frame *f)
290 {
291 	struct sk_buff *skb;
292 	struct aoe_hdr *h;
293 	struct aoe_atahdr *ah;
294 	char buf[128];
295 	u32 n;
296 
297 	n = newtag(d);
298 
299 	snprintf(buf, sizeof buf,
300 		"%15s e%ld.%ld oldtag=%08x@%08lx newtag=%08x\n",
301 		"retransmit",
302 		d->aoemajor, d->aoeminor, f->tag, jiffies, n);
303 	aoechr_error(buf);
304 
305 	skb = f->skb;
306 	h = aoe_hdr(skb);
307 	ah = (struct aoe_atahdr *) (h+1);
308 	f->tag = n;
309 	h->tag = cpu_to_be32(n);
310 	memcpy(h->dst, d->addr, sizeof h->dst);
311 	memcpy(h->src, d->ifp->dev_addr, sizeof h->src);
312 
313 	n = DEFAULTBCNT / 512;
314 	if (ah->scnt > n) {
315 		ah->scnt = n;
316 		if (ah->aflags & AOEAFL_WRITE) {
317 			skb_fill_page_desc(skb, 0, virt_to_page(f->bufaddr),
318 				offset_in_page(f->bufaddr), DEFAULTBCNT);
319 			skb->len = sizeof *h + sizeof *ah + DEFAULTBCNT;
320 			skb->data_len = DEFAULTBCNT;
321 		}
322 		if (++d->lostjumbo > (d->nframes << 1))
323 		if (d->maxbcnt != DEFAULTBCNT) {
324 			printk(KERN_INFO "aoe: e%ld.%ld: too many lost jumbo on %s - using 1KB frames.\n",
325 				d->aoemajor, d->aoeminor, d->ifp->name);
326 			d->maxbcnt = DEFAULTBCNT;
327 			d->flags |= DEVFL_MAXBCNT;
328 		}
329 	}
330 
331 	skb->dev = d->ifp;
332 	skb = skb_clone(skb, GFP_ATOMIC);
333 	if (skb == NULL)
334 		return;
335 	if (d->sendq_hd)
336 		d->sendq_tl->next = skb;
337 	else
338 		d->sendq_hd = skb;
339 	d->sendq_tl = skb;
340 }
341 
342 static int
343 tsince(int tag)
344 {
345 	int n;
346 
347 	n = jiffies & 0xffff;
348 	n -= tag & 0xffff;
349 	if (n < 0)
350 		n += 1<<16;
351 	return n;
352 }
353 
354 static void
355 rexmit_timer(ulong vp)
356 {
357 	struct aoedev *d;
358 	struct frame *f, *e;
359 	struct sk_buff *sl;
360 	register long timeout;
361 	ulong flags, n;
362 
363 	d = (struct aoedev *) vp;
364 	sl = NULL;
365 
366 	/* timeout is always ~150% of the moving average */
367 	timeout = d->rttavg;
368 	timeout += timeout >> 1;
369 
370 	spin_lock_irqsave(&d->lock, flags);
371 
372 	if (d->flags & DEVFL_TKILL) {
373 		spin_unlock_irqrestore(&d->lock, flags);
374 		return;
375 	}
376 	f = d->frames;
377 	e = f + d->nframes;
378 	for (; f<e; f++) {
379 		if (f->tag != FREETAG && tsince(f->tag) >= timeout) {
380 			n = f->waited += timeout;
381 			n /= HZ;
382 			if (n > aoe_deadsecs) { /* waited too long for response */
383 				aoedev_downdev(d);
384 				break;
385 			}
386 			rexmit(d, f);
387 		}
388 	}
389 	if (d->flags & DEVFL_KICKME) {
390 		d->flags &= ~DEVFL_KICKME;
391 		aoecmd_work(d);
392 	}
393 
394 	sl = d->sendq_hd;
395 	d->sendq_hd = d->sendq_tl = NULL;
396 	if (sl) {
397 		n = d->rttavg <<= 1;
398 		if (n > MAXTIMER)
399 			d->rttavg = MAXTIMER;
400 	}
401 
402 	d->timer.expires = jiffies + TIMERTICK;
403 	add_timer(&d->timer);
404 
405 	spin_unlock_irqrestore(&d->lock, flags);
406 
407 	aoenet_xmit(sl);
408 }
409 
410 /* this function performs work that has been deferred until sleeping is OK
411  */
412 void
413 aoecmd_sleepwork(struct work_struct *work)
414 {
415 	struct aoedev *d = container_of(work, struct aoedev, work);
416 
417 	if (d->flags & DEVFL_GDALLOC)
418 		aoeblk_gdalloc(d);
419 
420 	if (d->flags & DEVFL_NEWSIZE) {
421 		struct block_device *bd;
422 		unsigned long flags;
423 		u64 ssize;
424 
425 		ssize = d->gd->capacity;
426 		bd = bdget_disk(d->gd, 0);
427 
428 		if (bd) {
429 			mutex_lock(&bd->bd_inode->i_mutex);
430 			i_size_write(bd->bd_inode, (loff_t)ssize<<9);
431 			mutex_unlock(&bd->bd_inode->i_mutex);
432 			bdput(bd);
433 		}
434 		spin_lock_irqsave(&d->lock, flags);
435 		d->flags |= DEVFL_UP;
436 		d->flags &= ~DEVFL_NEWSIZE;
437 		spin_unlock_irqrestore(&d->lock, flags);
438 	}
439 }
440 
441 static void
442 ataid_complete(struct aoedev *d, unsigned char *id)
443 {
444 	u64 ssize;
445 	u16 n;
446 
447 	/* word 83: command set supported */
448 	n = le16_to_cpu(get_unaligned((__le16 *) &id[83<<1]));
449 
450 	/* word 86: command set/feature enabled */
451 	n |= le16_to_cpu(get_unaligned((__le16 *) &id[86<<1]));
452 
453 	if (n & (1<<10)) {	/* bit 10: LBA 48 */
454 		d->flags |= DEVFL_EXT;
455 
456 		/* word 100: number lba48 sectors */
457 		ssize = le64_to_cpu(get_unaligned((__le64 *) &id[100<<1]));
458 
459 		/* set as in ide-disk.c:init_idedisk_capacity */
460 		d->geo.cylinders = ssize;
461 		d->geo.cylinders /= (255 * 63);
462 		d->geo.heads = 255;
463 		d->geo.sectors = 63;
464 	} else {
465 		d->flags &= ~DEVFL_EXT;
466 
467 		/* number lba28 sectors */
468 		ssize = le32_to_cpu(get_unaligned((__le32 *) &id[60<<1]));
469 
470 		/* NOTE: obsolete in ATA 6 */
471 		d->geo.cylinders = le16_to_cpu(get_unaligned((__le16 *) &id[54<<1]));
472 		d->geo.heads = le16_to_cpu(get_unaligned((__le16 *) &id[55<<1]));
473 		d->geo.sectors = le16_to_cpu(get_unaligned((__le16 *) &id[56<<1]));
474 	}
475 
476 	if (d->ssize != ssize)
477 		printk(KERN_INFO "aoe: %012llx e%lu.%lu v%04x has %llu sectors\n",
478 			(unsigned long long)mac_addr(d->addr),
479 			d->aoemajor, d->aoeminor,
480 			d->fw_ver, (long long)ssize);
481 	d->ssize = ssize;
482 	d->geo.start = 0;
483 	if (d->gd != NULL) {
484 		d->gd->capacity = ssize;
485 		d->flags |= DEVFL_NEWSIZE;
486 	} else {
487 		if (d->flags & DEVFL_GDALLOC) {
488 			printk(KERN_ERR "aoe: can't schedule work for e%lu.%lu, %s\n",
489 			       d->aoemajor, d->aoeminor,
490 			       "it's already on!  This shouldn't happen.\n");
491 			return;
492 		}
493 		d->flags |= DEVFL_GDALLOC;
494 	}
495 	schedule_work(&d->work);
496 }
497 
498 static void
499 calc_rttavg(struct aoedev *d, int rtt)
500 {
501 	register long n;
502 
503 	n = rtt;
504 	if (n < 0) {
505 		n = -rtt;
506 		if (n < MINTIMER)
507 			n = MINTIMER;
508 		else if (n > MAXTIMER)
509 			n = MAXTIMER;
510 		d->mintimer += (n - d->mintimer) >> 1;
511 	} else if (n < d->mintimer)
512 		n = d->mintimer;
513 	else if (n > MAXTIMER)
514 		n = MAXTIMER;
515 
516 	/* g == .25; cf. Congestion Avoidance and Control, Jacobson & Karels; 1988 */
517 	n -= d->rttavg;
518 	d->rttavg += n >> 2;
519 }
520 
521 void
522 aoecmd_ata_rsp(struct sk_buff *skb)
523 {
524 	struct aoedev *d;
525 	struct aoe_hdr *hin, *hout;
526 	struct aoe_atahdr *ahin, *ahout;
527 	struct frame *f;
528 	struct buf *buf;
529 	struct sk_buff *sl;
530 	register long n;
531 	ulong flags;
532 	char ebuf[128];
533 	u16 aoemajor;
534 
535 	hin = aoe_hdr(skb);
536 	aoemajor = be16_to_cpu(get_unaligned(&hin->major));
537 	d = aoedev_by_aoeaddr(aoemajor, hin->minor);
538 	if (d == NULL) {
539 		snprintf(ebuf, sizeof ebuf, "aoecmd_ata_rsp: ata response "
540 			"for unknown device %d.%d\n",
541 			 aoemajor, hin->minor);
542 		aoechr_error(ebuf);
543 		return;
544 	}
545 
546 	spin_lock_irqsave(&d->lock, flags);
547 
548 	n = be32_to_cpu(get_unaligned(&hin->tag));
549 	f = getframe(d, n);
550 	if (f == NULL) {
551 		calc_rttavg(d, -tsince(n));
552 		spin_unlock_irqrestore(&d->lock, flags);
553 		snprintf(ebuf, sizeof ebuf,
554 			"%15s e%d.%d    tag=%08x@%08lx\n",
555 			"unexpected rsp",
556 			be16_to_cpu(get_unaligned(&hin->major)),
557 			hin->minor,
558 			be32_to_cpu(get_unaligned(&hin->tag)),
559 			jiffies);
560 		aoechr_error(ebuf);
561 		return;
562 	}
563 
564 	calc_rttavg(d, tsince(f->tag));
565 
566 	ahin = (struct aoe_atahdr *) (hin+1);
567 	hout = aoe_hdr(f->skb);
568 	ahout = (struct aoe_atahdr *) (hout+1);
569 	buf = f->buf;
570 
571 	if (ahout->cmdstat == WIN_IDENTIFY)
572 		d->flags &= ~DEVFL_PAUSE;
573 	if (ahin->cmdstat & 0xa9) {	/* these bits cleared on success */
574 		printk(KERN_ERR
575 			"aoe: ata error cmd=%2.2Xh stat=%2.2Xh from e%ld.%ld\n",
576 			ahout->cmdstat, ahin->cmdstat,
577 			d->aoemajor, d->aoeminor);
578 		if (buf)
579 			buf->flags |= BUFFL_FAIL;
580 	} else {
581 		n = ahout->scnt << 9;
582 		switch (ahout->cmdstat) {
583 		case WIN_READ:
584 		case WIN_READ_EXT:
585 			if (skb->len - sizeof *hin - sizeof *ahin < n) {
586 				printk(KERN_ERR
587 					"aoe: runt data size in read.  skb->len=%d\n",
588 					skb->len);
589 				/* fail frame f?  just returning will rexmit. */
590 				spin_unlock_irqrestore(&d->lock, flags);
591 				return;
592 			}
593 			memcpy(f->bufaddr, ahin+1, n);
594 		case WIN_WRITE:
595 		case WIN_WRITE_EXT:
596 			if (f->bcnt -= n) {
597 				skb = f->skb;
598 				f->bufaddr += n;
599 				put_lba(ahout, f->lba += ahout->scnt);
600 				n = f->bcnt;
601 				if (n > DEFAULTBCNT)
602 					n = DEFAULTBCNT;
603 				ahout->scnt = n >> 9;
604 				if (ahout->aflags & AOEAFL_WRITE) {
605 					skb_fill_page_desc(skb, 0,
606 						virt_to_page(f->bufaddr),
607 						offset_in_page(f->bufaddr), n);
608 					skb->len = sizeof *hout + sizeof *ahout + n;
609 					skb->data_len = n;
610 				}
611 				f->tag = newtag(d);
612 				hout->tag = cpu_to_be32(f->tag);
613 				skb->dev = d->ifp;
614 				skb = skb_clone(skb, GFP_ATOMIC);
615 				spin_unlock_irqrestore(&d->lock, flags);
616 				if (skb)
617 					aoenet_xmit(skb);
618 				return;
619 			}
620 			if (n > DEFAULTBCNT)
621 				d->lostjumbo = 0;
622 			break;
623 		case WIN_IDENTIFY:
624 			if (skb->len - sizeof *hin - sizeof *ahin < 512) {
625 				printk(KERN_INFO
626 					"aoe: runt data size in ataid.  skb->len=%d\n",
627 					skb->len);
628 				spin_unlock_irqrestore(&d->lock, flags);
629 				return;
630 			}
631 			ataid_complete(d, (char *) (ahin+1));
632 			break;
633 		default:
634 			printk(KERN_INFO
635 				"aoe: unrecognized ata command %2.2Xh for %d.%d\n",
636 				ahout->cmdstat,
637 				be16_to_cpu(get_unaligned(&hin->major)),
638 				hin->minor);
639 		}
640 	}
641 
642 	if (buf) {
643 		buf->nframesout -= 1;
644 		if (buf->nframesout == 0 && buf->resid == 0) {
645 			unsigned long duration = jiffies - buf->start_time;
646 			unsigned long n_sect = buf->bio->bi_size >> 9;
647 			struct gendisk *disk = d->gd;
648 			const int rw = bio_data_dir(buf->bio);
649 
650 			disk_stat_inc(disk, ios[rw]);
651 			disk_stat_add(disk, ticks[rw], duration);
652 			disk_stat_add(disk, sectors[rw], n_sect);
653 			disk_stat_add(disk, io_ticks, duration);
654 			n = (buf->flags & BUFFL_FAIL) ? -EIO : 0;
655 			bio_endio(buf->bio, buf->bio->bi_size, n);
656 			mempool_free(buf, d->bufpool);
657 		}
658 	}
659 
660 	f->buf = NULL;
661 	f->tag = FREETAG;
662 
663 	aoecmd_work(d);
664 	sl = d->sendq_hd;
665 	d->sendq_hd = d->sendq_tl = NULL;
666 
667 	spin_unlock_irqrestore(&d->lock, flags);
668 	aoenet_xmit(sl);
669 }
670 
671 void
672 aoecmd_cfg(ushort aoemajor, unsigned char aoeminor)
673 {
674 	struct sk_buff *sl;
675 
676 	sl = aoecmd_cfg_pkts(aoemajor, aoeminor, NULL);
677 
678 	aoenet_xmit(sl);
679 }
680 
681 /*
682  * Since we only call this in one place (and it only prepares one frame)
683  * we just return the skb.  Usually we'd chain it up to the aoedev sendq.
684  */
685 static struct sk_buff *
686 aoecmd_ata_id(struct aoedev *d)
687 {
688 	struct aoe_hdr *h;
689 	struct aoe_atahdr *ah;
690 	struct frame *f;
691 	struct sk_buff *skb;
692 
693 	f = freeframe(d);
694 	if (f == NULL) {
695 		printk(KERN_ERR "aoe: can't get a frame. This shouldn't happen.\n");
696 		return NULL;
697 	}
698 
699 	/* initialize the headers & frame */
700 	skb = f->skb;
701 	h = aoe_hdr(skb);
702 	ah = (struct aoe_atahdr *) (h+1);
703 	skb_put(skb, sizeof *h + sizeof *ah);
704 	memset(h, 0, skb->len);
705 	f->tag = aoehdr_atainit(d, h);
706 	f->waited = 0;
707 
708 	/* set up ata header */
709 	ah->scnt = 1;
710 	ah->cmdstat = WIN_IDENTIFY;
711 	ah->lba3 = 0xa0;
712 
713 	skb->dev = d->ifp;
714 
715 	d->rttavg = MAXTIMER;
716 	d->timer.function = rexmit_timer;
717 
718 	return skb_clone(skb, GFP_ATOMIC);
719 }
720 
721 void
722 aoecmd_cfg_rsp(struct sk_buff *skb)
723 {
724 	struct aoedev *d;
725 	struct aoe_hdr *h;
726 	struct aoe_cfghdr *ch;
727 	ulong flags, sysminor, aoemajor;
728 	struct sk_buff *sl;
729 	enum { MAXFRAMES = 16 };
730 	u16 n;
731 
732 	h = aoe_hdr(skb);
733 	ch = (struct aoe_cfghdr *) (h+1);
734 
735 	/*
736 	 * Enough people have their dip switches set backwards to
737 	 * warrant a loud message for this special case.
738 	 */
739 	aoemajor = be16_to_cpu(get_unaligned(&h->major));
740 	if (aoemajor == 0xfff) {
741 		printk(KERN_ERR "aoe: Warning: shelf address is all ones.  "
742 			"Check shelf dip switches.\n");
743 		return;
744 	}
745 
746 	sysminor = SYSMINOR(aoemajor, h->minor);
747 	if (sysminor * AOE_PARTITIONS + AOE_PARTITIONS > MINORMASK) {
748 		printk(KERN_INFO "aoe: e%ld.%d: minor number too large\n",
749 			aoemajor, (int) h->minor);
750 		return;
751 	}
752 
753 	n = be16_to_cpu(ch->bufcnt);
754 	if (n > MAXFRAMES)	/* keep it reasonable */
755 		n = MAXFRAMES;
756 
757 	d = aoedev_by_sysminor_m(sysminor, n);
758 	if (d == NULL) {
759 		printk(KERN_INFO "aoe: device sysminor_m failure\n");
760 		return;
761 	}
762 
763 	spin_lock_irqsave(&d->lock, flags);
764 
765 	/* permit device to migrate mac and network interface */
766 	d->ifp = skb->dev;
767 	memcpy(d->addr, h->src, sizeof d->addr);
768 	if (!(d->flags & DEVFL_MAXBCNT)) {
769 		n = d->ifp->mtu;
770 		n -= sizeof (struct aoe_hdr) + sizeof (struct aoe_atahdr);
771 		n /= 512;
772 		if (n > ch->scnt)
773 			n = ch->scnt;
774 		n = n ? n * 512 : DEFAULTBCNT;
775 		if (n != d->maxbcnt) {
776 			printk(KERN_INFO
777 				"aoe: e%ld.%ld: setting %d byte data frames on %s\n",
778 				d->aoemajor, d->aoeminor, n, d->ifp->name);
779 			d->maxbcnt = n;
780 		}
781 	}
782 
783 	/* don't change users' perspective */
784 	if (d->nopen && !(d->flags & DEVFL_PAUSE)) {
785 		spin_unlock_irqrestore(&d->lock, flags);
786 		return;
787 	}
788 	d->flags |= DEVFL_PAUSE;	/* force pause */
789 	d->mintimer = MINTIMER;
790 	d->fw_ver = be16_to_cpu(ch->fwver);
791 
792 	/* check for already outstanding ataid */
793 	sl = aoedev_isbusy(d) == 0 ? aoecmd_ata_id(d) : NULL;
794 
795 	spin_unlock_irqrestore(&d->lock, flags);
796 
797 	aoenet_xmit(sl);
798 }
799 
800