1/* Copyright (c) 2013 Coraid, Inc.  See COPYING for GPL terms. */
2/*
3 * aoecmd.c
4 * Filesystem request handling methods
5 */
6
7#include <linux/ata.h>
8#include <linux/slab.h>
9#include <linux/hdreg.h>
10#include <linux/blkdev.h>
11#include <linux/skbuff.h>
12#include <linux/netdevice.h>
13#include <linux/genhd.h>
14#include <linux/moduleparam.h>
15#include <linux/workqueue.h>
16#include <linux/kthread.h>
17#include <net/net_namespace.h>
18#include <asm/unaligned.h>
19#include <linux/uio.h>
20#include "aoe.h"
21
22#define MAXIOC (8192)	/* default meant to avoid most soft lockups */
23
24static void ktcomplete(struct frame *, struct sk_buff *);
25static int count_targets(struct aoedev *d, int *untainted);
26
27static struct buf *nextbuf(struct aoedev *);
28
29static int aoe_deadsecs = 60 * 3;
30module_param(aoe_deadsecs, int, 0644);
31MODULE_PARM_DESC(aoe_deadsecs, "After aoe_deadsecs seconds, give up and fail dev.");
32
33static int aoe_maxout = 64;
34module_param(aoe_maxout, int, 0644);
35MODULE_PARM_DESC(aoe_maxout,
36	"Only aoe_maxout outstanding packets for every MAC on eX.Y.");
37
38/* The number of online cpus during module initialization gives us a
39 * convenient heuristic cap on the parallelism used for ktio threads
40 * doing I/O completion.  It is not important that the cap equal the
41 * actual number of running CPUs at any given time, but because of CPU
42 * hotplug, we take care to use ncpus instead of using
43 * num_online_cpus() after module initialization.
44 */
45static int ncpus;
46
47/* mutex lock used for synchronization while thread spawning */
48static DEFINE_MUTEX(ktio_spawn_lock);
49
50static wait_queue_head_t *ktiowq;
51static struct ktstate *kts;
52
53/* io completion queue */
54struct iocq_ktio {
55	struct list_head head;
56	spinlock_t lock;
57};
58static struct iocq_ktio *iocq;
59
60static struct page *empty_page;
61
62static struct sk_buff *
63new_skb(ulong len)
64{
65	struct sk_buff *skb;
66
67	skb = alloc_skb(len + MAX_HEADER, GFP_ATOMIC);
68	if (skb) {
69		skb_reserve(skb, MAX_HEADER);
70		skb_reset_mac_header(skb);
71		skb_reset_network_header(skb);
72		skb->protocol = __constant_htons(ETH_P_AOE);
73		skb_checksum_none_assert(skb);
74	}
75	return skb;
76}
77
78static struct frame *
79getframe_deferred(struct aoedev *d, u32 tag)
80{
81	struct list_head *head, *pos, *nx;
82	struct frame *f;
83
84	head = &d->rexmitq;
85	list_for_each_safe(pos, nx, head) {
86		f = list_entry(pos, struct frame, head);
87		if (f->tag == tag) {
88			list_del(pos);
89			return f;
90		}
91	}
92	return NULL;
93}
94
95static struct frame *
96getframe(struct aoedev *d, u32 tag)
97{
98	struct frame *f;
99	struct list_head *head, *pos, *nx;
100	u32 n;
101
102	n = tag % NFACTIVE;
103	head = &d->factive[n];
104	list_for_each_safe(pos, nx, head) {
105		f = list_entry(pos, struct frame, head);
106		if (f->tag == tag) {
107			list_del(pos);
108			return f;
109		}
110	}
111	return NULL;
112}
113
114/*
115 * Leave the top bit clear so we have tagspace for userland.
116 * The bottom 16 bits are the xmit tick for rexmit/rttavg processing.
117 * This driver reserves tag -1 to mean "unused frame."
118 */
119static int
120newtag(struct aoedev *d)
121{
122	register ulong n;
123
124	n = jiffies & 0xffff;
125	return n |= (++d->lasttag & 0x7fff) << 16;
126}
127
128static u32
129aoehdr_atainit(struct aoedev *d, struct aoetgt *t, struct aoe_hdr *h)
130{
131	u32 host_tag = newtag(d);
132
133	memcpy(h->src, t->ifp->nd->dev_addr, sizeof h->src);
134	memcpy(h->dst, t->addr, sizeof h->dst);
135	h->type = __constant_cpu_to_be16(ETH_P_AOE);
136	h->verfl = AOE_HVER;
137	h->major = cpu_to_be16(d->aoemajor);
138	h->minor = d->aoeminor;
139	h->cmd = AOECMD_ATA;
140	h->tag = cpu_to_be32(host_tag);
141
142	return host_tag;
143}
144
145static inline void
146put_lba(struct aoe_atahdr *ah, sector_t lba)
147{
148	ah->lba0 = lba;
149	ah->lba1 = lba >>= 8;
150	ah->lba2 = lba >>= 8;
151	ah->lba3 = lba >>= 8;
152	ah->lba4 = lba >>= 8;
153	ah->lba5 = lba >>= 8;
154}
155
156static struct aoeif *
157ifrotate(struct aoetgt *t)
158{
159	struct aoeif *ifp;
160
161	ifp = t->ifp;
162	ifp++;
163	if (ifp >= &t->ifs[NAOEIFS] || ifp->nd == NULL)
164		ifp = t->ifs;
165	if (ifp->nd == NULL)
166		return NULL;
167	return t->ifp = ifp;
168}
169
170static void
171skb_pool_put(struct aoedev *d, struct sk_buff *skb)
172{
173	__skb_queue_tail(&d->skbpool, skb);
174}
175
176static struct sk_buff *
177skb_pool_get(struct aoedev *d)
178{
179	struct sk_buff *skb = skb_peek(&d->skbpool);
180
181	if (skb && atomic_read(&skb_shinfo(skb)->dataref) == 1) {
182		__skb_unlink(skb, &d->skbpool);
183		return skb;
184	}
185	if (skb_queue_len(&d->skbpool) < NSKBPOOLMAX &&
186	    (skb = new_skb(ETH_ZLEN)))
187		return skb;
188
189	return NULL;
190}
191
192void
193aoe_freetframe(struct frame *f)
194{
195	struct aoetgt *t;
196
197	t = f->t;
198	f->buf = NULL;
199	memset(&f->iter, 0, sizeof(f->iter));
200	f->r_skb = NULL;
201	f->flags = 0;
202	list_add(&f->head, &t->ffree);
203}
204
205static struct frame *
206newtframe(struct aoedev *d, struct aoetgt *t)
207{
208	struct frame *f;
209	struct sk_buff *skb;
210	struct list_head *pos;
211
212	if (list_empty(&t->ffree)) {
213		if (t->falloc >= NSKBPOOLMAX*2)
214			return NULL;
215		f = kcalloc(1, sizeof(*f), GFP_ATOMIC);
216		if (f == NULL)
217			return NULL;
218		t->falloc++;
219		f->t = t;
220	} else {
221		pos = t->ffree.next;
222		list_del(pos);
223		f = list_entry(pos, struct frame, head);
224	}
225
226	skb = f->skb;
227	if (skb == NULL) {
228		f->skb = skb = new_skb(ETH_ZLEN);
229		if (!skb) {
230bail:			aoe_freetframe(f);
231			return NULL;
232		}
233	}
234
235	if (atomic_read(&skb_shinfo(skb)->dataref) != 1) {
236		skb = skb_pool_get(d);
237		if (skb == NULL)
238			goto bail;
239		skb_pool_put(d, f->skb);
240		f->skb = skb;
241	}
242
243	skb->truesize -= skb->data_len;
244	skb_shinfo(skb)->nr_frags = skb->data_len = 0;
245	skb_trim(skb, 0);
246	return f;
247}
248
249static struct frame *
250newframe(struct aoedev *d)
251{
252	struct frame *f;
253	struct aoetgt *t, **tt;
254	int totout = 0;
255	int use_tainted;
256	int has_untainted;
257
258	if (!d->targets || !d->targets[0]) {
259		printk(KERN_ERR "aoe: NULL TARGETS!\n");
260		return NULL;
261	}
262	tt = d->tgt;	/* last used target */
263	for (use_tainted = 0, has_untainted = 0;;) {
264		tt++;
265		if (tt >= &d->targets[d->ntargets] || !*tt)
266			tt = d->targets;
267		t = *tt;
268		if (!t->taint) {
269			has_untainted = 1;
270			totout += t->nout;
271		}
272		if (t->nout < t->maxout
273		&& (use_tainted || !t->taint)
274		&& t->ifp->nd) {
275			f = newtframe(d, t);
276			if (f) {
277				ifrotate(t);
278				d->tgt = tt;
279				return f;
280			}
281		}
282		if (tt == d->tgt) {	/* we've looped and found nada */
283			if (!use_tainted && !has_untainted)
284				use_tainted = 1;
285			else
286				break;
287		}
288	}
289	if (totout == 0) {
290		d->kicked++;
291		d->flags |= DEVFL_KICKME;
292	}
293	return NULL;
294}
295
296static void
297skb_fillup(struct sk_buff *skb, struct bio *bio, struct bvec_iter iter)
298{
299	int frag = 0;
300	struct bio_vec bv;
301
302	__bio_for_each_segment(bv, bio, iter, iter)
303		skb_fill_page_desc(skb, frag++, bv.bv_page,
304				   bv.bv_offset, bv.bv_len);
305}
306
307static void
308fhash(struct frame *f)
309{
310	struct aoedev *d = f->t->d;
311	u32 n;
312
313	n = f->tag % NFACTIVE;
314	list_add_tail(&f->head, &d->factive[n]);
315}
316
317static void
318ata_rw_frameinit(struct frame *f)
319{
320	struct aoetgt *t;
321	struct aoe_hdr *h;
322	struct aoe_atahdr *ah;
323	struct sk_buff *skb;
324	char writebit, extbit;
325
326	skb = f->skb;
327	h = (struct aoe_hdr *) skb_mac_header(skb);
328	ah = (struct aoe_atahdr *) (h + 1);
329	skb_put(skb, sizeof(*h) + sizeof(*ah));
330	memset(h, 0, skb->len);
331
332	writebit = 0x10;
333	extbit = 0x4;
334
335	t = f->t;
336	f->tag = aoehdr_atainit(t->d, t, h);
337	fhash(f);
338	t->nout++;
339	f->waited = 0;
340	f->waited_total = 0;
341
342	/* set up ata header */
343	ah->scnt = f->iter.bi_size >> 9;
344	put_lba(ah, f->iter.bi_sector);
345	if (t->d->flags & DEVFL_EXT) {
346		ah->aflags |= AOEAFL_EXT;
347	} else {
348		extbit = 0;
349		ah->lba3 &= 0x0f;
350		ah->lba3 |= 0xe0;	/* LBA bit + obsolete 0xa0 */
351	}
352	if (f->buf && bio_data_dir(f->buf->bio) == WRITE) {
353		skb_fillup(skb, f->buf->bio, f->iter);
354		ah->aflags |= AOEAFL_WRITE;
355		skb->len += f->iter.bi_size;
356		skb->data_len = f->iter.bi_size;
357		skb->truesize += f->iter.bi_size;
358		t->wpkts++;
359	} else {
360		t->rpkts++;
361		writebit = 0;
362	}
363
364	ah->cmdstat = ATA_CMD_PIO_READ | writebit | extbit;
365	skb->dev = t->ifp->nd;
366}
367
368static int
369aoecmd_ata_rw(struct aoedev *d)
370{
371	struct frame *f;
372	struct buf *buf;
373	struct sk_buff *skb;
374	struct sk_buff_head queue;
375
376	buf = nextbuf(d);
377	if (buf == NULL)
378		return 0;
379	f = newframe(d);
380	if (f == NULL)
381		return 0;
382
383	/* initialize the headers & frame */
384	f->buf = buf;
385	f->iter = buf->iter;
386	f->iter.bi_size = min_t(unsigned long,
387				d->maxbcnt ?: DEFAULTBCNT,
388				f->iter.bi_size);
389	bio_advance_iter(buf->bio, &buf->iter, f->iter.bi_size);
390
391	if (!buf->iter.bi_size)
392		d->ip.buf = NULL;
393
394	/* mark all tracking fields and load out */
395	buf->nframesout += 1;
396
397	ata_rw_frameinit(f);
398
399	skb = skb_clone(f->skb, GFP_ATOMIC);
400	if (skb) {
401		do_gettimeofday(&f->sent);
402		f->sent_jiffs = (u32) jiffies;
403		__skb_queue_head_init(&queue);
404		__skb_queue_tail(&queue, skb);
405		aoenet_xmit(&queue);
406	}
407	return 1;
408}
409
410/* some callers cannot sleep, and they can call this function,
411 * transmitting the packets later, when interrupts are on
412 */
413static void
414aoecmd_cfg_pkts(ushort aoemajor, unsigned char aoeminor, struct sk_buff_head *queue)
415{
416	struct aoe_hdr *h;
417	struct aoe_cfghdr *ch;
418	struct sk_buff *skb;
419	struct net_device *ifp;
420
421	rcu_read_lock();
422	for_each_netdev_rcu(&init_net, ifp) {
423		dev_hold(ifp);
424		if (!is_aoe_netif(ifp))
425			goto cont;
426
427		skb = new_skb(sizeof *h + sizeof *ch);
428		if (skb == NULL) {
429			printk(KERN_INFO "aoe: skb alloc failure\n");
430			goto cont;
431		}
432		skb_put(skb, sizeof *h + sizeof *ch);
433		skb->dev = ifp;
434		__skb_queue_tail(queue, skb);
435		h = (struct aoe_hdr *) skb_mac_header(skb);
436		memset(h, 0, sizeof *h + sizeof *ch);
437
438		memset(h->dst, 0xff, sizeof h->dst);
439		memcpy(h->src, ifp->dev_addr, sizeof h->src);
440		h->type = __constant_cpu_to_be16(ETH_P_AOE);
441		h->verfl = AOE_HVER;
442		h->major = cpu_to_be16(aoemajor);
443		h->minor = aoeminor;
444		h->cmd = AOECMD_CFG;
445
446cont:
447		dev_put(ifp);
448	}
449	rcu_read_unlock();
450}
451
452static void
453resend(struct aoedev *d, struct frame *f)
454{
455	struct sk_buff *skb;
456	struct sk_buff_head queue;
457	struct aoe_hdr *h;
458	struct aoetgt *t;
459	char buf[128];
460	u32 n;
461
462	t = f->t;
463	n = newtag(d);
464	skb = f->skb;
465	if (ifrotate(t) == NULL) {
466		/* probably can't happen, but set it up to fail anyway */
467		pr_info("aoe: resend: no interfaces to rotate to.\n");
468		ktcomplete(f, NULL);
469		return;
470	}
471	h = (struct aoe_hdr *) skb_mac_header(skb);
472
473	if (!(f->flags & FFL_PROBE)) {
474		snprintf(buf, sizeof(buf),
475			"%15s e%ld.%d oldtag=%08x@%08lx newtag=%08x s=%pm d=%pm nout=%d\n",
476			"retransmit", d->aoemajor, d->aoeminor,
477			f->tag, jiffies, n,
478			h->src, h->dst, t->nout);
479		aoechr_error(buf);
480	}
481
482	f->tag = n;
483	fhash(f);
484	h->tag = cpu_to_be32(n);
485	memcpy(h->dst, t->addr, sizeof h->dst);
486	memcpy(h->src, t->ifp->nd->dev_addr, sizeof h->src);
487
488	skb->dev = t->ifp->nd;
489	skb = skb_clone(skb, GFP_ATOMIC);
490	if (skb == NULL)
491		return;
492	do_gettimeofday(&f->sent);
493	f->sent_jiffs = (u32) jiffies;
494	__skb_queue_head_init(&queue);
495	__skb_queue_tail(&queue, skb);
496	aoenet_xmit(&queue);
497}
498
499static int
500tsince_hr(struct frame *f)
501{
502	struct timeval now;
503	int n;
504
505	do_gettimeofday(&now);
506	n = now.tv_usec - f->sent.tv_usec;
507	n += (now.tv_sec - f->sent.tv_sec) * USEC_PER_SEC;
508
509	if (n < 0)
510		n = -n;
511
512	/* For relatively long periods, use jiffies to avoid
513	 * discrepancies caused by updates to the system time.
514	 *
515	 * On system with HZ of 1000, 32-bits is over 49 days
516	 * worth of jiffies, or over 71 minutes worth of usecs.
517	 *
518	 * Jiffies overflow is handled by subtraction of unsigned ints:
519	 * (gdb) print (unsigned) 2 - (unsigned) 0xfffffffe
520	 * $3 = 4
521	 * (gdb)
522	 */
523	if (n > USEC_PER_SEC / 4) {
524		n = ((u32) jiffies) - f->sent_jiffs;
525		n *= USEC_PER_SEC / HZ;
526	}
527
528	return n;
529}
530
531static int
532tsince(u32 tag)
533{
534	int n;
535
536	n = jiffies & 0xffff;
537	n -= tag & 0xffff;
538	if (n < 0)
539		n += 1<<16;
540	return jiffies_to_usecs(n + 1);
541}
542
543static struct aoeif *
544getif(struct aoetgt *t, struct net_device *nd)
545{
546	struct aoeif *p, *e;
547
548	p = t->ifs;
549	e = p + NAOEIFS;
550	for (; p < e; p++)
551		if (p->nd == nd)
552			return p;
553	return NULL;
554}
555
556static void
557ejectif(struct aoetgt *t, struct aoeif *ifp)
558{
559	struct aoeif *e;
560	struct net_device *nd;
561	ulong n;
562
563	nd = ifp->nd;
564	e = t->ifs + NAOEIFS - 1;
565	n = (e - ifp) * sizeof *ifp;
566	memmove(ifp, ifp+1, n);
567	e->nd = NULL;
568	dev_put(nd);
569}
570
571static struct frame *
572reassign_frame(struct frame *f)
573{
574	struct frame *nf;
575	struct sk_buff *skb;
576
577	nf = newframe(f->t->d);
578	if (!nf)
579		return NULL;
580	if (nf->t == f->t) {
581		aoe_freetframe(nf);
582		return NULL;
583	}
584
585	skb = nf->skb;
586	nf->skb = f->skb;
587	nf->buf = f->buf;
588	nf->iter = f->iter;
589	nf->waited = 0;
590	nf->waited_total = f->waited_total;
591	nf->sent = f->sent;
592	nf->sent_jiffs = f->sent_jiffs;
593	f->skb = skb;
594
595	return nf;
596}
597
598static void
599probe(struct aoetgt *t)
600{
601	struct aoedev *d;
602	struct frame *f;
603	struct sk_buff *skb;
604	struct sk_buff_head queue;
605	size_t n, m;
606	int frag;
607
608	d = t->d;
609	f = newtframe(d, t);
610	if (!f) {
611		pr_err("%s %pm for e%ld.%d: %s\n",
612			"aoe: cannot probe remote address",
613			t->addr,
614			(long) d->aoemajor, d->aoeminor,
615			"no frame available");
616		return;
617	}
618	f->flags |= FFL_PROBE;
619	ifrotate(t);
620	f->iter.bi_size = t->d->maxbcnt ? t->d->maxbcnt : DEFAULTBCNT;
621	ata_rw_frameinit(f);
622	skb = f->skb;
623	for (frag = 0, n = f->iter.bi_size; n > 0; ++frag, n -= m) {
624		if (n < PAGE_SIZE)
625			m = n;
626		else
627			m = PAGE_SIZE;
628		skb_fill_page_desc(skb, frag, empty_page, 0, m);
629	}
630	skb->len += f->iter.bi_size;
631	skb->data_len = f->iter.bi_size;
632	skb->truesize += f->iter.bi_size;
633
634	skb = skb_clone(f->skb, GFP_ATOMIC);
635	if (skb) {
636		do_gettimeofday(&f->sent);
637		f->sent_jiffs = (u32) jiffies;
638		__skb_queue_head_init(&queue);
639		__skb_queue_tail(&queue, skb);
640		aoenet_xmit(&queue);
641	}
642}
643
644static long
645rto(struct aoedev *d)
646{
647	long t;
648
649	t = 2 * d->rttavg >> RTTSCALE;
650	t += 8 * d->rttdev >> RTTDSCALE;
651	if (t == 0)
652		t = 1;
653
654	return t;
655}
656
657static void
658rexmit_deferred(struct aoedev *d)
659{
660	struct aoetgt *t;
661	struct frame *f;
662	struct frame *nf;
663	struct list_head *pos, *nx, *head;
664	int since;
665	int untainted;
666
667	count_targets(d, &untainted);
668
669	head = &d->rexmitq;
670	list_for_each_safe(pos, nx, head) {
671		f = list_entry(pos, struct frame, head);
672		t = f->t;
673		if (t->taint) {
674			if (!(f->flags & FFL_PROBE)) {
675				nf = reassign_frame(f);
676				if (nf) {
677					if (t->nout_probes == 0
678					&& untainted > 0) {
679						probe(t);
680						t->nout_probes++;
681					}
682					list_replace(&f->head, &nf->head);
683					pos = &nf->head;
684					aoe_freetframe(f);
685					f = nf;
686					t = f->t;
687				}
688			} else if (untainted < 1) {
689				/* don't probe w/o other untainted aoetgts */
690				goto stop_probe;
691			} else if (tsince_hr(f) < t->taint * rto(d)) {
692				/* reprobe slowly when taint is high */
693				continue;
694			}
695		} else if (f->flags & FFL_PROBE) {
696stop_probe:		/* don't probe untainted aoetgts */
697			list_del(pos);
698			aoe_freetframe(f);
699			/* leaving d->kicked, because this is routine */
700			f->t->d->flags |= DEVFL_KICKME;
701			continue;
702		}
703		if (t->nout >= t->maxout)
704			continue;
705		list_del(pos);
706		t->nout++;
707		if (f->flags & FFL_PROBE)
708			t->nout_probes++;
709		since = tsince_hr(f);
710		f->waited += since;
711		f->waited_total += since;
712		resend(d, f);
713	}
714}
715
716/* An aoetgt accumulates demerits quickly, and successful
717 * probing redeems the aoetgt slowly.
718 */
719static void
720scorn(struct aoetgt *t)
721{
722	int n;
723
724	n = t->taint++;
725	t->taint += t->taint * 2;
726	if (n > t->taint)
727		t->taint = n;
728	if (t->taint > MAX_TAINT)
729		t->taint = MAX_TAINT;
730}
731
732static int
733count_targets(struct aoedev *d, int *untainted)
734{
735	int i, good;
736
737	for (i = good = 0; i < d->ntargets && d->targets[i]; ++i)
738		if (d->targets[i]->taint == 0)
739			good++;
740
741	if (untainted)
742		*untainted = good;
743	return i;
744}
745
746static void
747rexmit_timer(ulong vp)
748{
749	struct aoedev *d;
750	struct aoetgt *t;
751	struct aoeif *ifp;
752	struct frame *f;
753	struct list_head *head, *pos, *nx;
754	LIST_HEAD(flist);
755	register long timeout;
756	ulong flags, n;
757	int i;
758	int utgts;	/* number of aoetgt descriptors (not slots) */
759	int since;
760
761	d = (struct aoedev *) vp;
762
763	spin_lock_irqsave(&d->lock, flags);
764
765	/* timeout based on observed timings and variations */
766	timeout = rto(d);
767
768	utgts = count_targets(d, NULL);
769
770	if (d->flags & DEVFL_TKILL) {
771		spin_unlock_irqrestore(&d->lock, flags);
772		return;
773	}
774
775	/* collect all frames to rexmit into flist */
776	for (i = 0; i < NFACTIVE; i++) {
777		head = &d->factive[i];
778		list_for_each_safe(pos, nx, head) {
779			f = list_entry(pos, struct frame, head);
780			if (tsince_hr(f) < timeout)
781				break;	/* end of expired frames */
782			/* move to flist for later processing */
783			list_move_tail(pos, &flist);
784		}
785	}
786
787	/* process expired frames */
788	while (!list_empty(&flist)) {
789		pos = flist.next;
790		f = list_entry(pos, struct frame, head);
791		since = tsince_hr(f);
792		n = f->waited_total + since;
793		n /= USEC_PER_SEC;
794		if (aoe_deadsecs
795		&& n > aoe_deadsecs
796		&& !(f->flags & FFL_PROBE)) {
797			/* Waited too long.  Device failure.
798			 * Hang all frames on first hash bucket for downdev
799			 * to clean up.
800			 */
801			list_splice(&flist, &d->factive[0]);
802			aoedev_downdev(d);
803			goto out;
804		}
805
806		t = f->t;
807		n = f->waited + since;
808		n /= USEC_PER_SEC;
809		if (aoe_deadsecs && utgts > 0
810		&& (n > aoe_deadsecs / utgts || n > HARD_SCORN_SECS))
811			scorn(t); /* avoid this target */
812
813		if (t->maxout != 1) {
814			t->ssthresh = t->maxout / 2;
815			t->maxout = 1;
816		}
817
818		if (f->flags & FFL_PROBE) {
819			t->nout_probes--;
820		} else {
821			ifp = getif(t, f->skb->dev);
822			if (ifp && ++ifp->lost > (t->nframes << 1)
823			&& (ifp != t->ifs || t->ifs[1].nd)) {
824				ejectif(t, ifp);
825				ifp = NULL;
826			}
827		}
828		list_move_tail(pos, &d->rexmitq);
829		t->nout--;
830	}
831	rexmit_deferred(d);
832
833out:
834	if ((d->flags & DEVFL_KICKME) && d->blkq) {
835		d->flags &= ~DEVFL_KICKME;
836		d->blkq->request_fn(d->blkq);
837	}
838
839	d->timer.expires = jiffies + TIMERTICK;
840	add_timer(&d->timer);
841
842	spin_unlock_irqrestore(&d->lock, flags);
843}
844
845static unsigned long
846rqbiocnt(struct request *r)
847{
848	struct bio *bio;
849	unsigned long n = 0;
850
851	__rq_for_each_bio(bio, r)
852		n++;
853	return n;
854}
855
856/* This can be removed if we are certain that no users of the block
857 * layer will ever use zero-count pages in bios.  Otherwise we have to
858 * protect against the put_page sometimes done by the network layer.
859 *
860 * See http://oss.sgi.com/archives/xfs/2007-01/msg00594.html for
861 * discussion.
862 *
863 * We cannot use get_page in the workaround, because it insists on a
864 * positive page count as a precondition.  So we use _count directly.
865 */
866static void
867bio_pageinc(struct bio *bio)
868{
869	struct bio_vec bv;
870	struct page *page;
871	struct bvec_iter iter;
872
873	bio_for_each_segment(bv, bio, iter) {
874		/* Non-zero page count for non-head members of
875		 * compound pages is no longer allowed by the kernel.
876		 */
877		page = compound_head(bv.bv_page);
878		atomic_inc(&page->_count);
879	}
880}
881
882static void
883bio_pagedec(struct bio *bio)
884{
885	struct page *page;
886	struct bio_vec bv;
887	struct bvec_iter iter;
888
889	bio_for_each_segment(bv, bio, iter) {
890		page = compound_head(bv.bv_page);
891		atomic_dec(&page->_count);
892	}
893}
894
895static void
896bufinit(struct buf *buf, struct request *rq, struct bio *bio)
897{
898	memset(buf, 0, sizeof(*buf));
899	buf->rq = rq;
900	buf->bio = bio;
901	buf->iter = bio->bi_iter;
902	bio_pageinc(bio);
903}
904
905static struct buf *
906nextbuf(struct aoedev *d)
907{
908	struct request *rq;
909	struct request_queue *q;
910	struct buf *buf;
911	struct bio *bio;
912
913	q = d->blkq;
914	if (q == NULL)
915		return NULL;	/* initializing */
916	if (d->ip.buf)
917		return d->ip.buf;
918	rq = d->ip.rq;
919	if (rq == NULL) {
920		rq = blk_peek_request(q);
921		if (rq == NULL)
922			return NULL;
923		blk_start_request(rq);
924		d->ip.rq = rq;
925		d->ip.nxbio = rq->bio;
926		rq->special = (void *) rqbiocnt(rq);
927	}
928	buf = mempool_alloc(d->bufpool, GFP_ATOMIC);
929	if (buf == NULL) {
930		pr_err("aoe: nextbuf: unable to mempool_alloc!\n");
931		return NULL;
932	}
933	bio = d->ip.nxbio;
934	bufinit(buf, rq, bio);
935	bio = bio->bi_next;
936	d->ip.nxbio = bio;
937	if (bio == NULL)
938		d->ip.rq = NULL;
939	return d->ip.buf = buf;
940}
941
942/* enters with d->lock held */
943void
944aoecmd_work(struct aoedev *d)
945{
946	rexmit_deferred(d);
947	while (aoecmd_ata_rw(d))
948		;
949}
950
951/* this function performs work that has been deferred until sleeping is OK
952 */
953void
954aoecmd_sleepwork(struct work_struct *work)
955{
956	struct aoedev *d = container_of(work, struct aoedev, work);
957	struct block_device *bd;
958	u64 ssize;
959
960	if (d->flags & DEVFL_GDALLOC)
961		aoeblk_gdalloc(d);
962
963	if (d->flags & DEVFL_NEWSIZE) {
964		ssize = get_capacity(d->gd);
965		bd = bdget_disk(d->gd, 0);
966		if (bd) {
967			mutex_lock(&bd->bd_inode->i_mutex);
968			i_size_write(bd->bd_inode, (loff_t)ssize<<9);
969			mutex_unlock(&bd->bd_inode->i_mutex);
970			bdput(bd);
971		}
972		spin_lock_irq(&d->lock);
973		d->flags |= DEVFL_UP;
974		d->flags &= ~DEVFL_NEWSIZE;
975		spin_unlock_irq(&d->lock);
976	}
977}
978
979static void
980ata_ident_fixstring(u16 *id, int ns)
981{
982	u16 s;
983
984	while (ns-- > 0) {
985		s = *id;
986		*id++ = s >> 8 | s << 8;
987	}
988}
989
990static void
991ataid_complete(struct aoedev *d, struct aoetgt *t, unsigned char *id)
992{
993	u64 ssize;
994	u16 n;
995
996	/* word 83: command set supported */
997	n = get_unaligned_le16(&id[83 << 1]);
998
999	/* word 86: command set/feature enabled */
1000	n |= get_unaligned_le16(&id[86 << 1]);
1001
1002	if (n & (1<<10)) {	/* bit 10: LBA 48 */
1003		d->flags |= DEVFL_EXT;
1004
1005		/* word 100: number lba48 sectors */
1006		ssize = get_unaligned_le64(&id[100 << 1]);
1007
1008		/* set as in ide-disk.c:init_idedisk_capacity */
1009		d->geo.cylinders = ssize;
1010		d->geo.cylinders /= (255 * 63);
1011		d->geo.heads = 255;
1012		d->geo.sectors = 63;
1013	} else {
1014		d->flags &= ~DEVFL_EXT;
1015
1016		/* number lba28 sectors */
1017		ssize = get_unaligned_le32(&id[60 << 1]);
1018
1019		/* NOTE: obsolete in ATA 6 */
1020		d->geo.cylinders = get_unaligned_le16(&id[54 << 1]);
1021		d->geo.heads = get_unaligned_le16(&id[55 << 1]);
1022		d->geo.sectors = get_unaligned_le16(&id[56 << 1]);
1023	}
1024
1025	ata_ident_fixstring((u16 *) &id[10<<1], 10);	/* serial */
1026	ata_ident_fixstring((u16 *) &id[23<<1], 4);	/* firmware */
1027	ata_ident_fixstring((u16 *) &id[27<<1], 20);	/* model */
1028	memcpy(d->ident, id, sizeof(d->ident));
1029
1030	if (d->ssize != ssize)
1031		printk(KERN_INFO
1032			"aoe: %pm e%ld.%d v%04x has %llu sectors\n",
1033			t->addr,
1034			d->aoemajor, d->aoeminor,
1035			d->fw_ver, (long long)ssize);
1036	d->ssize = ssize;
1037	d->geo.start = 0;
1038	if (d->flags & (DEVFL_GDALLOC|DEVFL_NEWSIZE))
1039		return;
1040	if (d->gd != NULL) {
1041		set_capacity(d->gd, ssize);
1042		d->flags |= DEVFL_NEWSIZE;
1043	} else
1044		d->flags |= DEVFL_GDALLOC;
1045	schedule_work(&d->work);
1046}
1047
1048static void
1049calc_rttavg(struct aoedev *d, struct aoetgt *t, int rtt)
1050{
1051	register long n;
1052
1053	n = rtt;
1054
1055	/* cf. Congestion Avoidance and Control, Jacobson & Karels, 1988 */
1056	n -= d->rttavg >> RTTSCALE;
1057	d->rttavg += n;
1058	if (n < 0)
1059		n = -n;
1060	n -= d->rttdev >> RTTDSCALE;
1061	d->rttdev += n;
1062
1063	if (!t || t->maxout >= t->nframes)
1064		return;
1065	if (t->maxout < t->ssthresh)
1066		t->maxout += 1;
1067	else if (t->nout == t->maxout && t->next_cwnd-- == 0) {
1068		t->maxout += 1;
1069		t->next_cwnd = t->maxout;
1070	}
1071}
1072
1073static struct aoetgt *
1074gettgt(struct aoedev *d, char *addr)
1075{
1076	struct aoetgt **t, **e;
1077
1078	t = d->targets;
1079	e = t + d->ntargets;
1080	for (; t < e && *t; t++)
1081		if (memcmp((*t)->addr, addr, sizeof((*t)->addr)) == 0)
1082			return *t;
1083	return NULL;
1084}
1085
1086static void
1087bvcpy(struct sk_buff *skb, struct bio *bio, struct bvec_iter iter, long cnt)
1088{
1089	int soff = 0;
1090	struct bio_vec bv;
1091
1092	iter.bi_size = cnt;
1093
1094	__bio_for_each_segment(bv, bio, iter, iter) {
1095		char *p = page_address(bv.bv_page) + bv.bv_offset;
1096		skb_copy_bits(skb, soff, p, bv.bv_len);
1097		soff += bv.bv_len;
1098	}
1099}
1100
1101void
1102aoe_end_request(struct aoedev *d, struct request *rq, int fastfail)
1103{
1104	struct bio *bio;
1105	int bok;
1106	struct request_queue *q;
1107
1108	q = d->blkq;
1109	if (rq == d->ip.rq)
1110		d->ip.rq = NULL;
1111	do {
1112		bio = rq->bio;
1113		bok = !fastfail && test_bit(BIO_UPTODATE, &bio->bi_flags);
1114	} while (__blk_end_request(rq, bok ? 0 : -EIO, bio->bi_iter.bi_size));
1115
1116	/* cf. http://lkml.org/lkml/2006/10/31/28 */
1117	if (!fastfail)
1118		__blk_run_queue(q);
1119}
1120
1121static void
1122aoe_end_buf(struct aoedev *d, struct buf *buf)
1123{
1124	struct request *rq;
1125	unsigned long n;
1126
1127	if (buf == d->ip.buf)
1128		d->ip.buf = NULL;
1129	rq = buf->rq;
1130	bio_pagedec(buf->bio);
1131	mempool_free(buf, d->bufpool);
1132	n = (unsigned long) rq->special;
1133	rq->special = (void *) --n;
1134	if (n == 0)
1135		aoe_end_request(d, rq, 0);
1136}
1137
1138static void
1139ktiocomplete(struct frame *f)
1140{
1141	struct aoe_hdr *hin, *hout;
1142	struct aoe_atahdr *ahin, *ahout;
1143	struct buf *buf;
1144	struct sk_buff *skb;
1145	struct aoetgt *t;
1146	struct aoeif *ifp;
1147	struct aoedev *d;
1148	long n;
1149	int untainted;
1150
1151	if (f == NULL)
1152		return;
1153
1154	t = f->t;
1155	d = t->d;
1156	skb = f->r_skb;
1157	buf = f->buf;
1158	if (f->flags & FFL_PROBE)
1159		goto out;
1160	if (!skb)		/* just fail the buf. */
1161		goto noskb;
1162
1163	hout = (struct aoe_hdr *) skb_mac_header(f->skb);
1164	ahout = (struct aoe_atahdr *) (hout+1);
1165
1166	hin = (struct aoe_hdr *) skb->data;
1167	skb_pull(skb, sizeof(*hin));
1168	ahin = (struct aoe_atahdr *) skb->data;
1169	skb_pull(skb, sizeof(*ahin));
1170	if (ahin->cmdstat & 0xa9) {	/* these bits cleared on success */
1171		pr_err("aoe: ata error cmd=%2.2Xh stat=%2.2Xh from e%ld.%d\n",
1172			ahout->cmdstat, ahin->cmdstat,
1173			d->aoemajor, d->aoeminor);
1174noskb:		if (buf)
1175			clear_bit(BIO_UPTODATE, &buf->bio->bi_flags);
1176		goto out;
1177	}
1178
1179	n = ahout->scnt << 9;
1180	switch (ahout->cmdstat) {
1181	case ATA_CMD_PIO_READ:
1182	case ATA_CMD_PIO_READ_EXT:
1183		if (skb->len < n) {
1184			pr_err("%s e%ld.%d.  skb->len=%d need=%ld\n",
1185				"aoe: runt data size in read from",
1186				(long) d->aoemajor, d->aoeminor,
1187			       skb->len, n);
1188			clear_bit(BIO_UPTODATE, &buf->bio->bi_flags);
1189			break;
1190		}
1191		if (n > f->iter.bi_size) {
1192			pr_err_ratelimited("%s e%ld.%d.  bytes=%ld need=%u\n",
1193				"aoe: too-large data size in read from",
1194				(long) d->aoemajor, d->aoeminor,
1195				n, f->iter.bi_size);
1196			clear_bit(BIO_UPTODATE, &buf->bio->bi_flags);
1197			break;
1198		}
1199		bvcpy(skb, f->buf->bio, f->iter, n);
1200	case ATA_CMD_PIO_WRITE:
1201	case ATA_CMD_PIO_WRITE_EXT:
1202		spin_lock_irq(&d->lock);
1203		ifp = getif(t, skb->dev);
1204		if (ifp)
1205			ifp->lost = 0;
1206		spin_unlock_irq(&d->lock);
1207		break;
1208	case ATA_CMD_ID_ATA:
1209		if (skb->len < 512) {
1210			pr_info("%s e%ld.%d.  skb->len=%d need=512\n",
1211				"aoe: runt data size in ataid from",
1212				(long) d->aoemajor, d->aoeminor,
1213				skb->len);
1214			break;
1215		}
1216		if (skb_linearize(skb))
1217			break;
1218		spin_lock_irq(&d->lock);
1219		ataid_complete(d, t, skb->data);
1220		spin_unlock_irq(&d->lock);
1221		break;
1222	default:
1223		pr_info("aoe: unrecognized ata command %2.2Xh for %d.%d\n",
1224			ahout->cmdstat,
1225			be16_to_cpu(get_unaligned(&hin->major)),
1226			hin->minor);
1227	}
1228out:
1229	spin_lock_irq(&d->lock);
1230	if (t->taint > 0
1231	&& --t->taint > 0
1232	&& t->nout_probes == 0) {
1233		count_targets(d, &untainted);
1234		if (untainted > 0) {
1235			probe(t);
1236			t->nout_probes++;
1237		}
1238	}
1239
1240	aoe_freetframe(f);
1241
1242	if (buf && --buf->nframesout == 0 && buf->iter.bi_size == 0)
1243		aoe_end_buf(d, buf);
1244
1245	spin_unlock_irq(&d->lock);
1246	aoedev_put(d);
1247	dev_kfree_skb(skb);
1248}
1249
1250/* Enters with iocq.lock held.
1251 * Returns true iff responses needing processing remain.
1252 */
1253static int
1254ktio(int id)
1255{
1256	struct frame *f;
1257	struct list_head *pos;
1258	int i;
1259	int actual_id;
1260
1261	for (i = 0; ; ++i) {
1262		if (i == MAXIOC)
1263			return 1;
1264		if (list_empty(&iocq[id].head))
1265			return 0;
1266		pos = iocq[id].head.next;
1267		list_del(pos);
1268		f = list_entry(pos, struct frame, head);
1269		spin_unlock_irq(&iocq[id].lock);
1270		ktiocomplete(f);
1271
1272		/* Figure out if extra threads are required. */
1273		actual_id = f->t->d->aoeminor % ncpus;
1274
1275		if (!kts[actual_id].active) {
1276			BUG_ON(id != 0);
1277			mutex_lock(&ktio_spawn_lock);
1278			if (!kts[actual_id].active
1279				&& aoe_ktstart(&kts[actual_id]) == 0)
1280				kts[actual_id].active = 1;
1281			mutex_unlock(&ktio_spawn_lock);
1282		}
1283		spin_lock_irq(&iocq[id].lock);
1284	}
1285}
1286
1287static int
1288kthread(void *vp)
1289{
1290	struct ktstate *k;
1291	DECLARE_WAITQUEUE(wait, current);
1292	int more;
1293
1294	k = vp;
1295	current->flags |= PF_NOFREEZE;
1296	set_user_nice(current, -10);
1297	complete(&k->rendez);	/* tell spawner we're running */
1298	do {
1299		spin_lock_irq(k->lock);
1300		more = k->fn(k->id);
1301		if (!more) {
1302			add_wait_queue(k->waitq, &wait);
1303			__set_current_state(TASK_INTERRUPTIBLE);
1304		}
1305		spin_unlock_irq(k->lock);
1306		if (!more) {
1307			schedule();
1308			remove_wait_queue(k->waitq, &wait);
1309		} else
1310			cond_resched();
1311	} while (!kthread_should_stop());
1312	complete(&k->rendez);	/* tell spawner we're stopping */
1313	return 0;
1314}
1315
1316void
1317aoe_ktstop(struct ktstate *k)
1318{
1319	kthread_stop(k->task);
1320	wait_for_completion(&k->rendez);
1321}
1322
1323int
1324aoe_ktstart(struct ktstate *k)
1325{
1326	struct task_struct *task;
1327
1328	init_completion(&k->rendez);
1329	task = kthread_run(kthread, k, "%s", k->name);
1330	if (task == NULL || IS_ERR(task))
1331		return -ENOMEM;
1332	k->task = task;
1333	wait_for_completion(&k->rendez); /* allow kthread to start */
1334	init_completion(&k->rendez);	/* for waiting for exit later */
1335	return 0;
1336}
1337
1338/* pass it off to kthreads for processing */
1339static void
1340ktcomplete(struct frame *f, struct sk_buff *skb)
1341{
1342	int id;
1343	ulong flags;
1344
1345	f->r_skb = skb;
1346	id = f->t->d->aoeminor % ncpus;
1347	spin_lock_irqsave(&iocq[id].lock, flags);
1348	if (!kts[id].active) {
1349		spin_unlock_irqrestore(&iocq[id].lock, flags);
1350		/* The thread with id has not been spawned yet,
1351		 * so delegate the work to the main thread and
1352		 * try spawning a new thread.
1353		 */
1354		id = 0;
1355		spin_lock_irqsave(&iocq[id].lock, flags);
1356	}
1357	list_add_tail(&f->head, &iocq[id].head);
1358	spin_unlock_irqrestore(&iocq[id].lock, flags);
1359	wake_up(&ktiowq[id]);
1360}
1361
1362struct sk_buff *
1363aoecmd_ata_rsp(struct sk_buff *skb)
1364{
1365	struct aoedev *d;
1366	struct aoe_hdr *h;
1367	struct frame *f;
1368	u32 n;
1369	ulong flags;
1370	char ebuf[128];
1371	u16 aoemajor;
1372
1373	h = (struct aoe_hdr *) skb->data;
1374	aoemajor = be16_to_cpu(get_unaligned(&h->major));
1375	d = aoedev_by_aoeaddr(aoemajor, h->minor, 0);
1376	if (d == NULL) {
1377		snprintf(ebuf, sizeof ebuf, "aoecmd_ata_rsp: ata response "
1378			"for unknown device %d.%d\n",
1379			aoemajor, h->minor);
1380		aoechr_error(ebuf);
1381		return skb;
1382	}
1383
1384	spin_lock_irqsave(&d->lock, flags);
1385
1386	n = be32_to_cpu(get_unaligned(&h->tag));
1387	f = getframe(d, n);
1388	if (f) {
1389		calc_rttavg(d, f->t, tsince_hr(f));
1390		f->t->nout--;
1391		if (f->flags & FFL_PROBE)
1392			f->t->nout_probes--;
1393	} else {
1394		f = getframe_deferred(d, n);
1395		if (f) {
1396			calc_rttavg(d, NULL, tsince_hr(f));
1397		} else {
1398			calc_rttavg(d, NULL, tsince(n));
1399			spin_unlock_irqrestore(&d->lock, flags);
1400			aoedev_put(d);
1401			snprintf(ebuf, sizeof(ebuf),
1402				 "%15s e%d.%d    tag=%08x@%08lx s=%pm d=%pm\n",
1403				 "unexpected rsp",
1404				 get_unaligned_be16(&h->major),
1405				 h->minor,
1406				 get_unaligned_be32(&h->tag),
1407				 jiffies,
1408				 h->src,
1409				 h->dst);
1410			aoechr_error(ebuf);
1411			return skb;
1412		}
1413	}
1414	aoecmd_work(d);
1415
1416	spin_unlock_irqrestore(&d->lock, flags);
1417
1418	ktcomplete(f, skb);
1419
1420	/*
1421	 * Note here that we do not perform an aoedev_put, as we are
1422	 * leaving this reference for the ktio to release.
1423	 */
1424	return NULL;
1425}
1426
1427void
1428aoecmd_cfg(ushort aoemajor, unsigned char aoeminor)
1429{
1430	struct sk_buff_head queue;
1431
1432	__skb_queue_head_init(&queue);
1433	aoecmd_cfg_pkts(aoemajor, aoeminor, &queue);
1434	aoenet_xmit(&queue);
1435}
1436
1437struct sk_buff *
1438aoecmd_ata_id(struct aoedev *d)
1439{
1440	struct aoe_hdr *h;
1441	struct aoe_atahdr *ah;
1442	struct frame *f;
1443	struct sk_buff *skb;
1444	struct aoetgt *t;
1445
1446	f = newframe(d);
1447	if (f == NULL)
1448		return NULL;
1449
1450	t = *d->tgt;
1451
1452	/* initialize the headers & frame */
1453	skb = f->skb;
1454	h = (struct aoe_hdr *) skb_mac_header(skb);
1455	ah = (struct aoe_atahdr *) (h+1);
1456	skb_put(skb, sizeof *h + sizeof *ah);
1457	memset(h, 0, skb->len);
1458	f->tag = aoehdr_atainit(d, t, h);
1459	fhash(f);
1460	t->nout++;
1461	f->waited = 0;
1462	f->waited_total = 0;
1463
1464	/* set up ata header */
1465	ah->scnt = 1;
1466	ah->cmdstat = ATA_CMD_ID_ATA;
1467	ah->lba3 = 0xa0;
1468
1469	skb->dev = t->ifp->nd;
1470
1471	d->rttavg = RTTAVG_INIT;
1472	d->rttdev = RTTDEV_INIT;
1473	d->timer.function = rexmit_timer;
1474
1475	skb = skb_clone(skb, GFP_ATOMIC);
1476	if (skb) {
1477		do_gettimeofday(&f->sent);
1478		f->sent_jiffs = (u32) jiffies;
1479	}
1480
1481	return skb;
1482}
1483
1484static struct aoetgt **
1485grow_targets(struct aoedev *d)
1486{
1487	ulong oldn, newn;
1488	struct aoetgt **tt;
1489
1490	oldn = d->ntargets;
1491	newn = oldn * 2;
1492	tt = kcalloc(newn, sizeof(*d->targets), GFP_ATOMIC);
1493	if (!tt)
1494		return NULL;
1495	memmove(tt, d->targets, sizeof(*d->targets) * oldn);
1496	d->tgt = tt + (d->tgt - d->targets);
1497	kfree(d->targets);
1498	d->targets = tt;
1499	d->ntargets = newn;
1500
1501	return &d->targets[oldn];
1502}
1503
1504static struct aoetgt *
1505addtgt(struct aoedev *d, char *addr, ulong nframes)
1506{
1507	struct aoetgt *t, **tt, **te;
1508
1509	tt = d->targets;
1510	te = tt + d->ntargets;
1511	for (; tt < te && *tt; tt++)
1512		;
1513
1514	if (tt == te) {
1515		tt = grow_targets(d);
1516		if (!tt)
1517			goto nomem;
1518	}
1519	t = kzalloc(sizeof(*t), GFP_ATOMIC);
1520	if (!t)
1521		goto nomem;
1522	t->nframes = nframes;
1523	t->d = d;
1524	memcpy(t->addr, addr, sizeof t->addr);
1525	t->ifp = t->ifs;
1526	aoecmd_wreset(t);
1527	t->maxout = t->nframes / 2;
1528	INIT_LIST_HEAD(&t->ffree);
1529	return *tt = t;
1530
1531 nomem:
1532	pr_info("aoe: cannot allocate memory to add target\n");
1533	return NULL;
1534}
1535
1536static void
1537setdbcnt(struct aoedev *d)
1538{
1539	struct aoetgt **t, **e;
1540	int bcnt = 0;
1541
1542	t = d->targets;
1543	e = t + d->ntargets;
1544	for (; t < e && *t; t++)
1545		if (bcnt == 0 || bcnt > (*t)->minbcnt)
1546			bcnt = (*t)->minbcnt;
1547	if (bcnt != d->maxbcnt) {
1548		d->maxbcnt = bcnt;
1549		pr_info("aoe: e%ld.%d: setting %d byte data frames\n",
1550			d->aoemajor, d->aoeminor, bcnt);
1551	}
1552}
1553
1554static void
1555setifbcnt(struct aoetgt *t, struct net_device *nd, int bcnt)
1556{
1557	struct aoedev *d;
1558	struct aoeif *p, *e;
1559	int minbcnt;
1560
1561	d = t->d;
1562	minbcnt = bcnt;
1563	p = t->ifs;
1564	e = p + NAOEIFS;
1565	for (; p < e; p++) {
1566		if (p->nd == NULL)
1567			break;		/* end of the valid interfaces */
1568		if (p->nd == nd) {
1569			p->bcnt = bcnt;	/* we're updating */
1570			nd = NULL;
1571		} else if (minbcnt > p->bcnt)
1572			minbcnt = p->bcnt; /* find the min interface */
1573	}
1574	if (nd) {
1575		if (p == e) {
1576			pr_err("aoe: device setifbcnt failure; too many interfaces.\n");
1577			return;
1578		}
1579		dev_hold(nd);
1580		p->nd = nd;
1581		p->bcnt = bcnt;
1582	}
1583	t->minbcnt = minbcnt;
1584	setdbcnt(d);
1585}
1586
1587void
1588aoecmd_cfg_rsp(struct sk_buff *skb)
1589{
1590	struct aoedev *d;
1591	struct aoe_hdr *h;
1592	struct aoe_cfghdr *ch;
1593	struct aoetgt *t;
1594	ulong flags, aoemajor;
1595	struct sk_buff *sl;
1596	struct sk_buff_head queue;
1597	u16 n;
1598
1599	sl = NULL;
1600	h = (struct aoe_hdr *) skb_mac_header(skb);
1601	ch = (struct aoe_cfghdr *) (h+1);
1602
1603	/*
1604	 * Enough people have their dip switches set backwards to
1605	 * warrant a loud message for this special case.
1606	 */
1607	aoemajor = get_unaligned_be16(&h->major);
1608	if (aoemajor == 0xfff) {
1609		printk(KERN_ERR "aoe: Warning: shelf address is all ones.  "
1610			"Check shelf dip switches.\n");
1611		return;
1612	}
1613	if (aoemajor == 0xffff) {
1614		pr_info("aoe: e%ld.%d: broadcast shelf number invalid\n",
1615			aoemajor, (int) h->minor);
1616		return;
1617	}
1618	if (h->minor == 0xff) {
1619		pr_info("aoe: e%ld.%d: broadcast slot number invalid\n",
1620			aoemajor, (int) h->minor);
1621		return;
1622	}
1623
1624	n = be16_to_cpu(ch->bufcnt);
1625	if (n > aoe_maxout)	/* keep it reasonable */
1626		n = aoe_maxout;
1627
1628	d = aoedev_by_aoeaddr(aoemajor, h->minor, 1);
1629	if (d == NULL) {
1630		pr_info("aoe: device allocation failure\n");
1631		return;
1632	}
1633
1634	spin_lock_irqsave(&d->lock, flags);
1635
1636	t = gettgt(d, h->src);
1637	if (t) {
1638		t->nframes = n;
1639		if (n < t->maxout)
1640			aoecmd_wreset(t);
1641	} else {
1642		t = addtgt(d, h->src, n);
1643		if (!t)
1644			goto bail;
1645	}
1646	n = skb->dev->mtu;
1647	n -= sizeof(struct aoe_hdr) + sizeof(struct aoe_atahdr);
1648	n /= 512;
1649	if (n > ch->scnt)
1650		n = ch->scnt;
1651	n = n ? n * 512 : DEFAULTBCNT;
1652	setifbcnt(t, skb->dev, n);
1653
1654	/* don't change users' perspective */
1655	if (d->nopen == 0) {
1656		d->fw_ver = be16_to_cpu(ch->fwver);
1657		sl = aoecmd_ata_id(d);
1658	}
1659bail:
1660	spin_unlock_irqrestore(&d->lock, flags);
1661	aoedev_put(d);
1662	if (sl) {
1663		__skb_queue_head_init(&queue);
1664		__skb_queue_tail(&queue, sl);
1665		aoenet_xmit(&queue);
1666	}
1667}
1668
1669void
1670aoecmd_wreset(struct aoetgt *t)
1671{
1672	t->maxout = 1;
1673	t->ssthresh = t->nframes / 2;
1674	t->next_cwnd = t->nframes;
1675}
1676
1677void
1678aoecmd_cleanslate(struct aoedev *d)
1679{
1680	struct aoetgt **t, **te;
1681
1682	d->rttavg = RTTAVG_INIT;
1683	d->rttdev = RTTDEV_INIT;
1684	d->maxbcnt = 0;
1685
1686	t = d->targets;
1687	te = t + d->ntargets;
1688	for (; t < te && *t; t++)
1689		aoecmd_wreset(*t);
1690}
1691
1692void
1693aoe_failbuf(struct aoedev *d, struct buf *buf)
1694{
1695	if (buf == NULL)
1696		return;
1697	buf->iter.bi_size = 0;
1698	clear_bit(BIO_UPTODATE, &buf->bio->bi_flags);
1699	if (buf->nframesout == 0)
1700		aoe_end_buf(d, buf);
1701}
1702
1703void
1704aoe_flush_iocq(void)
1705{
1706	int i;
1707
1708	for (i = 0; i < ncpus; i++) {
1709		if (kts[i].active)
1710			aoe_flush_iocq_by_index(i);
1711	}
1712}
1713
1714void
1715aoe_flush_iocq_by_index(int id)
1716{
1717	struct frame *f;
1718	struct aoedev *d;
1719	LIST_HEAD(flist);
1720	struct list_head *pos;
1721	struct sk_buff *skb;
1722	ulong flags;
1723
1724	spin_lock_irqsave(&iocq[id].lock, flags);
1725	list_splice_init(&iocq[id].head, &flist);
1726	spin_unlock_irqrestore(&iocq[id].lock, flags);
1727	while (!list_empty(&flist)) {
1728		pos = flist.next;
1729		list_del(pos);
1730		f = list_entry(pos, struct frame, head);
1731		d = f->t->d;
1732		skb = f->r_skb;
1733		spin_lock_irqsave(&d->lock, flags);
1734		if (f->buf) {
1735			f->buf->nframesout--;
1736			aoe_failbuf(d, f->buf);
1737		}
1738		aoe_freetframe(f);
1739		spin_unlock_irqrestore(&d->lock, flags);
1740		dev_kfree_skb(skb);
1741		aoedev_put(d);
1742	}
1743}
1744
1745int __init
1746aoecmd_init(void)
1747{
1748	void *p;
1749	int i;
1750	int ret;
1751
1752	/* get_zeroed_page returns page with ref count 1 */
1753	p = (void *) get_zeroed_page(GFP_KERNEL | __GFP_REPEAT);
1754	if (!p)
1755		return -ENOMEM;
1756	empty_page = virt_to_page(p);
1757
1758	ncpus = num_online_cpus();
1759
1760	iocq = kcalloc(ncpus, sizeof(struct iocq_ktio), GFP_KERNEL);
1761	if (!iocq)
1762		return -ENOMEM;
1763
1764	kts = kcalloc(ncpus, sizeof(struct ktstate), GFP_KERNEL);
1765	if (!kts) {
1766		ret = -ENOMEM;
1767		goto kts_fail;
1768	}
1769
1770	ktiowq = kcalloc(ncpus, sizeof(wait_queue_head_t), GFP_KERNEL);
1771	if (!ktiowq) {
1772		ret = -ENOMEM;
1773		goto ktiowq_fail;
1774	}
1775
1776	mutex_init(&ktio_spawn_lock);
1777
1778	for (i = 0; i < ncpus; i++) {
1779		INIT_LIST_HEAD(&iocq[i].head);
1780		spin_lock_init(&iocq[i].lock);
1781		init_waitqueue_head(&ktiowq[i]);
1782		snprintf(kts[i].name, sizeof(kts[i].name), "aoe_ktio%d", i);
1783		kts[i].fn = ktio;
1784		kts[i].waitq = &ktiowq[i];
1785		kts[i].lock = &iocq[i].lock;
1786		kts[i].id = i;
1787		kts[i].active = 0;
1788	}
1789	kts[0].active = 1;
1790	if (aoe_ktstart(&kts[0])) {
1791		ret = -ENOMEM;
1792		goto ktstart_fail;
1793	}
1794	return 0;
1795
1796ktstart_fail:
1797	kfree(ktiowq);
1798ktiowq_fail:
1799	kfree(kts);
1800kts_fail:
1801	kfree(iocq);
1802
1803	return ret;
1804}
1805
1806void
1807aoecmd_exit(void)
1808{
1809	int i;
1810
1811	for (i = 0; i < ncpus; i++)
1812		if (kts[i].active)
1813			aoe_ktstop(&kts[i]);
1814
1815	aoe_flush_iocq();
1816
1817	/* Free up the iocq and thread speicific configuration
1818	* allocated during startup.
1819	*/
1820	kfree(iocq);
1821	kfree(kts);
1822	kfree(ktiowq);
1823
1824	free_page((unsigned long) page_address(empty_page));
1825	empty_page = NULL;
1826}
1827