Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1751 insertions, 0 deletions

diff --git a/drivers/block/aoe/aoecmd.c b/drivers/block/aoe/aoecmd.c
new file mode 100644
index 000000000..d7317425b
--- /dev/null
+++ b/drivers/block/aoe/aoecmd.c
@@ -0,0 +1,1751 @@
+/* Copyright (c) 2013 Coraid, Inc.  See COPYING for GPL terms. */
+/*
+ * aoecmd.c
+ * Filesystem request handling methods
+ */
+
+#include <linux/ata.h>
+#include <linux/slab.h>
+#include <linux/hdreg.h>
+#include <linux/blk-mq.h>
+#include <linux/skbuff.h>
+#include <linux/netdevice.h>
+#include <linux/moduleparam.h>
+#include <linux/workqueue.h>
+#include <linux/kthread.h>
+#include <net/net_namespace.h>
+#include <asm/unaligned.h>
+#include <linux/uio.h>
+#include "aoe.h"
+
+#define MAXIOC (8192)	/* default meant to avoid most soft lockups */
+
+static void ktcomplete(struct frame *, struct sk_buff *);
+static int count_targets(struct aoedev *d, int *untainted);
+
+static struct buf *nextbuf(struct aoedev *);
+
+static int aoe_deadsecs = 60 * 3;
+module_param(aoe_deadsecs, int, 0644);
+MODULE_PARM_DESC(aoe_deadsecs, "After aoe_deadsecs seconds, give up and fail dev.");
+
+static int aoe_maxout = 64;
+module_param(aoe_maxout, int, 0644);
+MODULE_PARM_DESC(aoe_maxout,
+	"Only aoe_maxout outstanding packets for every MAC on eX.Y.");
+
+/* The number of online cpus during module initialization gives us a
+ * convenient heuristic cap on the parallelism used for ktio threads
+ * doing I/O completion.  It is not important that the cap equal the
+ * actual number of running CPUs at any given time, but because of CPU
+ * hotplug, we take care to use ncpus instead of using
+ * num_online_cpus() after module initialization.
+ */
+static int ncpus;
+
+/* mutex lock used for synchronization while thread spawning */
+static DEFINE_MUTEX(ktio_spawn_lock);
+
+static wait_queue_head_t *ktiowq;
+static struct ktstate *kts;
+
+/* io completion queue */
+struct iocq_ktio {
+	struct list_head head;
+	spinlock_t lock;
+};
+static struct iocq_ktio *iocq;
+
+static struct page *empty_page;
+
+static struct sk_buff *
+new_skb(ulong len)
+{
+	struct sk_buff *skb;
+
+	skb = alloc_skb(len + MAX_HEADER, GFP_ATOMIC);
+	if (skb) {
+		skb_reserve(skb, MAX_HEADER);
+		skb_reset_mac_header(skb);
+		skb_reset_network_header(skb);
+		skb->protocol = __constant_htons(ETH_P_AOE);
+		skb_checksum_none_assert(skb);
+	}
+	return skb;
+}
+
+static struct frame *
+getframe_deferred(struct aoedev *d, u32 tag)
+{
+	struct list_head *head, *pos, *nx;
+	struct frame *f;
+
+	head = &d->rexmitq;
+	list_for_each_safe(pos, nx, head) {
+		f = list_entry(pos, struct frame, head);
+		if (f->tag == tag) {
+			list_del(pos);
+			return f;
+		}
+	}
+	return NULL;
+}
+
+static struct frame *
+getframe(struct aoedev *d, u32 tag)
+{
+	struct frame *f;
+	struct list_head *head, *pos, *nx;
+	u32 n;
+
+	n = tag % NFACTIVE;
+	head = &d->factive[n];
+	list_for_each_safe(pos, nx, head) {
+		f = list_entry(pos, struct frame, head);
+		if (f->tag == tag) {
+			list_del(pos);
+			return f;
+		}
+	}
+	return NULL;
+}
+
+/*
+ * Leave the top bit clear so we have tagspace for userland.
+ * The bottom 16 bits are the xmit tick for rexmit/rttavg processing.
+ * This driver reserves tag -1 to mean "unused frame."
+ */
+static int
+newtag(struct aoedev *d)
+{
+	register ulong n;
+
+	n = jiffies & 0xffff;
+	return n | (++d->lasttag & 0x7fff) << 16;
+}
+
+static u32
+aoehdr_atainit(struct aoedev *d, struct aoetgt *t, struct aoe_hdr *h)
+{
+	u32 host_tag = newtag(d);
+
+	memcpy(h->src, t->ifp->nd->dev_addr, sizeof h->src);
+	memcpy(h->dst, t->addr, sizeof h->dst);
+	h->type = __constant_cpu_to_be16(ETH_P_AOE);
+	h->verfl = AOE_HVER;
+	h->major = cpu_to_be16(d->aoemajor);
+	h->minor = d->aoeminor;
+	h->cmd = AOECMD_ATA;
+	h->tag = cpu_to_be32(host_tag);
+
+	return host_tag;
+}
+
+static inline void
+put_lba(struct aoe_atahdr *ah, sector_t lba)
+{
+	ah->lba0 = lba;
+	ah->lba1 = lba >>= 8;
+	ah->lba2 = lba >>= 8;
+	ah->lba3 = lba >>= 8;
+	ah->lba4 = lba >>= 8;
+	ah->lba5 = lba >>= 8;
+}
+
+static struct aoeif *
+ifrotate(struct aoetgt *t)
+{
+	struct aoeif *ifp;
+
+	ifp = t->ifp;
+	ifp++;
+	if (ifp >= &t->ifs[NAOEIFS] || ifp->nd == NULL)
+		ifp = t->ifs;
+	if (ifp->nd == NULL)
+		return NULL;
+	return t->ifp = ifp;
+}
+
+static void
+skb_pool_put(struct aoedev *d, struct sk_buff *skb)
+{
+	__skb_queue_tail(&d->skbpool, skb);
+}
+
+static struct sk_buff *
+skb_pool_get(struct aoedev *d)
+{
+	struct sk_buff *skb = skb_peek(&d->skbpool);
+
+	if (skb && atomic_read(&skb_shinfo(skb)->dataref) == 1) {
+		__skb_unlink(skb, &d->skbpool);
+		return skb;
+	}
+	if (skb_queue_len(&d->skbpool) < NSKBPOOLMAX &&
+	    (skb = new_skb(ETH_ZLEN)))
+		return skb;
+
+	return NULL;
+}
+
+void
+aoe_freetframe(struct frame *f)
+{
+	struct aoetgt *t;
+
+	t = f->t;
+	f->buf = NULL;
+	memset(&f->iter, 0, sizeof(f->iter));
+	f->r_skb = NULL;
+	f->flags = 0;
+	list_add(&f->head, &t->ffree);
+}
+
+static struct frame *
+newtframe(struct aoedev *d, struct aoetgt *t)
+{
+	struct frame *f;
+	struct sk_buff *skb;
+	struct list_head *pos;
+
+	if (list_empty(&t->ffree)) {
+		if (t->falloc >= NSKBPOOLMAX*2)
+			return NULL;
+		f = kcalloc(1, sizeof(*f), GFP_ATOMIC);
+		if (f == NULL)
+			return NULL;
+		t->falloc++;
+		f->t = t;
+	} else {
+		pos = t->ffree.next;
+		list_del(pos);
+		f = list_entry(pos, struct frame, head);
+	}
+
+	skb = f->skb;
+	if (skb == NULL) {
+		f->skb = skb = new_skb(ETH_ZLEN);
+		if (!skb) {
+bail:			aoe_freetframe(f);
+			return NULL;
+		}
+	}
+
+	if (atomic_read(&skb_shinfo(skb)->dataref) != 1) {
+		skb = skb_pool_get(d);
+		if (skb == NULL)
+			goto bail;
+		skb_pool_put(d, f->skb);
+		f->skb = skb;
+	}
+
+	skb->truesize -= skb->data_len;
+	skb_shinfo(skb)->nr_frags = skb->data_len = 0;
+	skb_trim(skb, 0);
+	return f;
+}
+
+static struct frame *
+newframe(struct aoedev *d)
+{
+	struct frame *f;
+	struct aoetgt *t, **tt;
+	int totout = 0;
+	int use_tainted;
+	int has_untainted;
+
+	if (!d->targets || !d->targets[0]) {
+		printk(KERN_ERR "aoe: NULL TARGETS!\n");
+		return NULL;
+	}
+	tt = d->tgt;	/* last used target */
+	for (use_tainted = 0, has_untainted = 0;;) {
+		tt++;
+		if (tt >= &d->targets[d->ntargets] || !*tt)
+			tt = d->targets;
+		t = *tt;
+		if (!t->taint) {
+			has_untainted = 1;
+			totout += t->nout;
+		}
+		if (t->nout < t->maxout
+		&& (use_tainted || !t->taint)
+		&& t->ifp->nd) {
+			f = newtframe(d, t);
+			if (f) {
+				ifrotate(t);
+				d->tgt = tt;
+				return f;
+			}
+		}
+		if (tt == d->tgt) {	/* we've looped and found nada */
+			if (!use_tainted && !has_untainted)
+				use_tainted = 1;
+			else
+				break;
+		}
+	}
+	if (totout == 0) {
+		d->kicked++;
+		d->flags |= DEVFL_KICKME;
+	}
+	return NULL;
+}
+
+static void
+skb_fillup(struct sk_buff *skb, struct bio *bio, struct bvec_iter iter)
+{
+	int frag = 0;
+	struct bio_vec bv;
+
+	__bio_for_each_segment(bv, bio, iter, iter)
+		skb_fill_page_desc(skb, frag++, bv.bv_page,
+				   bv.bv_offset, bv.bv_len);
+}
+
+static void
+fhash(struct frame *f)
+{
+	struct aoedev *d = f->t->d;
+	u32 n;
+
+	n = f->tag % NFACTIVE;
+	list_add_tail(&f->head, &d->factive[n]);
+}
+
+static void
+ata_rw_frameinit(struct frame *f)
+{
+	struct aoetgt *t;
+	struct aoe_hdr *h;
+	struct aoe_atahdr *ah;
+	struct sk_buff *skb;
+	char writebit, extbit;
+
+	skb = f->skb;
+	h = (struct aoe_hdr *) skb_mac_header(skb);
+	ah = (struct aoe_atahdr *) (h + 1);
+	skb_put(skb, sizeof(*h) + sizeof(*ah));
+	memset(h, 0, skb->len);
+
+	writebit = 0x10;
+	extbit = 0x4;
+
+	t = f->t;
+	f->tag = aoehdr_atainit(t->d, t, h);
+	fhash(f);
+	t->nout++;
+	f->waited = 0;
+	f->waited_total = 0;
+
+	/* set up ata header */
+	ah->scnt = f->iter.bi_size >> 9;
+	put_lba(ah, f->iter.bi_sector);
+	if (t->d->flags & DEVFL_EXT) {
+		ah->aflags |= AOEAFL_EXT;
+	} else {
+		extbit = 0;
+		ah->lba3 &= 0x0f;
+		ah->lba3 |= 0xe0;	/* LBA bit + obsolete 0xa0 */
+	}
+	if (f->buf && bio_data_dir(f->buf->bio) == WRITE) {
+		skb_fillup(skb, f->buf->bio, f->iter);
+		ah->aflags |= AOEAFL_WRITE;
+		skb->len += f->iter.bi_size;
+		skb->data_len = f->iter.bi_size;
+		skb->truesize += f->iter.bi_size;
+		t->wpkts++;
+	} else {
+		t->rpkts++;
+		writebit = 0;
+	}
+
+	ah->cmdstat = ATA_CMD_PIO_READ | writebit | extbit;
+	skb->dev = t->ifp->nd;
+}
+
+static int
+aoecmd_ata_rw(struct aoedev *d)
+{
+	struct frame *f;
+	struct buf *buf;
+	struct sk_buff *skb;
+	struct sk_buff_head queue;
+
+	buf = nextbuf(d);
+	if (buf == NULL)
+		return 0;
+	f = newframe(d);
+	if (f == NULL)
+		return 0;
+
+	/* initialize the headers & frame */
+	f->buf = buf;
+	f->iter = buf->iter;
+	f->iter.bi_size = min_t(unsigned long,
+				d->maxbcnt ?: DEFAULTBCNT,
+				f->iter.bi_size);
+	bio_advance_iter(buf->bio, &buf->iter, f->iter.bi_size);
+
+	if (!buf->iter.bi_size)
+		d->ip.buf = NULL;
+
+	/* mark all tracking fields and load out */
+	buf->nframesout += 1;
+
+	ata_rw_frameinit(f);
+
+	skb = skb_clone(f->skb, GFP_ATOMIC);
+	if (skb) {
+		f->sent = ktime_get();
+		__skb_queue_head_init(&queue);
+		__skb_queue_tail(&queue, skb);
+		aoenet_xmit(&queue);
+	}
+	return 1;
+}
+
+/* some callers cannot sleep, and they can call this function,
+ * transmitting the packets later, when interrupts are on
+ */
+static void
+aoecmd_cfg_pkts(ushort aoemajor, unsigned char aoeminor, struct sk_buff_head *queue)
+{
+	struct aoe_hdr *h;
+	struct aoe_cfghdr *ch;
+	struct sk_buff *skb;
+	struct net_device *ifp;
+
+	rcu_read_lock();
+	for_each_netdev_rcu(&init_net, ifp) {
+		dev_hold(ifp);
+		if (!is_aoe_netif(ifp))
+			goto cont;
+
+		skb = new_skb(sizeof *h + sizeof *ch);
+		if (skb == NULL) {
+			printk(KERN_INFO "aoe: skb alloc failure\n");
+			goto cont;
+		}
+		skb_put(skb, sizeof *h + sizeof *ch);
+		skb->dev = ifp;
+		__skb_queue_tail(queue, skb);
+		h = (struct aoe_hdr *) skb_mac_header(skb);
+		memset(h, 0, sizeof *h + sizeof *ch);
+
+		memset(h->dst, 0xff, sizeof h->dst);
+		memcpy(h->src, ifp->dev_addr, sizeof h->src);
+		h->type = __constant_cpu_to_be16(ETH_P_AOE);
+		h->verfl = AOE_HVER;
+		h->major = cpu_to_be16(aoemajor);
+		h->minor = aoeminor;
+		h->cmd = AOECMD_CFG;
+
+cont:
+		dev_put(ifp);
+	}
+	rcu_read_unlock();
+}
+
+static void
+resend(struct aoedev *d, struct frame *f)
+{
+	struct sk_buff *skb;
+	struct sk_buff_head queue;
+	struct aoe_hdr *h;
+	struct aoetgt *t;
+	char buf[128];
+	u32 n;
+
+	t = f->t;
+	n = newtag(d);
+	skb = f->skb;
+	if (ifrotate(t) == NULL) {
+		/* probably can't happen, but set it up to fail anyway */
+		pr_info("aoe: resend: no interfaces to rotate to.\n");
+		ktcomplete(f, NULL);
+		return;
+	}
+	h = (struct aoe_hdr *) skb_mac_header(skb);
+
+	if (!(f->flags & FFL_PROBE)) {
+		snprintf(buf, sizeof(buf),
+			"%15s e%ld.%d oldtag=%08x@%08lx newtag=%08x s=%pm d=%pm nout=%d\n",
+			"retransmit", d->aoemajor, d->aoeminor,
+			f->tag, jiffies, n,
+			h->src, h->dst, t->nout);
+		aoechr_error(buf);
+	}
+
+	f->tag = n;
+	fhash(f);
+	h->tag = cpu_to_be32(n);
+	memcpy(h->dst, t->addr, sizeof h->dst);
+	memcpy(h->src, t->ifp->nd->dev_addr, sizeof h->src);
+
+	skb->dev = t->ifp->nd;
+	skb = skb_clone(skb, GFP_ATOMIC);
+	if (skb == NULL)
+		return;
+	f->sent = ktime_get();
+	__skb_queue_head_init(&queue);
+	__skb_queue_tail(&queue, skb);
+	aoenet_xmit(&queue);
+}
+
+static int
+tsince_hr(struct frame *f)
+{
+	u64 delta = ktime_to_ns(ktime_sub(ktime_get(), f->sent));
+
+	/* delta is normally under 4.2 seconds, avoid 64-bit division */
+	if (likely(delta <= UINT_MAX))
+		return (u32)delta / NSEC_PER_USEC;
+
+	/* avoid overflow after 71 minutes */
+	if (delta > ((u64)INT_MAX * NSEC_PER_USEC))
+		return INT_MAX;
+
+	return div_u64(delta, NSEC_PER_USEC);
+}
+
+static int
+tsince(u32 tag)
+{
+	int n;
+
+	n = jiffies & 0xffff;
+	n -= tag & 0xffff;
+	if (n < 0)
+		n += 1<<16;
+	return jiffies_to_usecs(n + 1);
+}
+
+static struct aoeif *
+getif(struct aoetgt *t, struct net_device *nd)
+{
+	struct aoeif *p, *e;
+
+	p = t->ifs;
+	e = p + NAOEIFS;
+	for (; p < e; p++)
+		if (p->nd == nd)
+			return p;
+	return NULL;
+}
+
+static void
+ejectif(struct aoetgt *t, struct aoeif *ifp)
+{
+	struct aoeif *e;
+	struct net_device *nd;
+	ulong n;
+
+	nd = ifp->nd;
+	e = t->ifs + NAOEIFS - 1;
+	n = (e - ifp) * sizeof *ifp;
+	memmove(ifp, ifp+1, n);
+	e->nd = NULL;
+	dev_put(nd);
+}
+
+static struct frame *
+reassign_frame(struct frame *f)
+{
+	struct frame *nf;
+	struct sk_buff *skb;
+
+	nf = newframe(f->t->d);
+	if (!nf)
+		return NULL;
+	if (nf->t == f->t) {
+		aoe_freetframe(nf);
+		return NULL;
+	}
+
+	skb = nf->skb;
+	nf->skb = f->skb;
+	nf->buf = f->buf;
+	nf->iter = f->iter;
+	nf->waited = 0;
+	nf->waited_total = f->waited_total;
+	nf->sent = f->sent;
+	f->skb = skb;
+
+	return nf;
+}
+
+static void
+probe(struct aoetgt *t)
+{
+	struct aoedev *d;
+	struct frame *f;
+	struct sk_buff *skb;
+	struct sk_buff_head queue;
+	size_t n, m;
+	int frag;
+
+	d = t->d;
+	f = newtframe(d, t);
+	if (!f) {
+		pr_err("%s %pm for e%ld.%d: %s\n",
+			"aoe: cannot probe remote address",
+			t->addr,
+			(long) d->aoemajor, d->aoeminor,
+			"no frame available");
+		return;
+	}
+	f->flags |= FFL_PROBE;
+	ifrotate(t);
+	f->iter.bi_size = t->d->maxbcnt ? t->d->maxbcnt : DEFAULTBCNT;
+	ata_rw_frameinit(f);
+	skb = f->skb;
+	for (frag = 0, n = f->iter.bi_size; n > 0; ++frag, n -= m) {
+		if (n < PAGE_SIZE)
+			m = n;
+		else
+			m = PAGE_SIZE;
+		skb_fill_page_desc(skb, frag, empty_page, 0, m);
+	}
+	skb->len += f->iter.bi_size;
+	skb->data_len = f->iter.bi_size;
+	skb->truesize += f->iter.bi_size;
+
+	skb = skb_clone(f->skb, GFP_ATOMIC);
+	if (skb) {
+		f->sent = ktime_get();
+		__skb_queue_head_init(&queue);
+		__skb_queue_tail(&queue, skb);
+		aoenet_xmit(&queue);
+	}
+}
+
+static long
+rto(struct aoedev *d)
+{
+	long t;
+
+	t = 2 * d->rttavg >> RTTSCALE;
+	t += 8 * d->rttdev >> RTTDSCALE;
+	if (t == 0)
+		t = 1;
+
+	return t;
+}
+
+static void
+rexmit_deferred(struct aoedev *d)
+{
+	struct aoetgt *t;
+	struct frame *f;
+	struct frame *nf;
+	struct list_head *pos, *nx, *head;
+	int since;
+	int untainted;
+
+	count_targets(d, &untainted);
+
+	head = &d->rexmitq;
+	list_for_each_safe(pos, nx, head) {
+		f = list_entry(pos, struct frame, head);
+		t = f->t;
+		if (t->taint) {
+			if (!(f->flags & FFL_PROBE)) {
+				nf = reassign_frame(f);
+				if (nf) {
+					if (t->nout_probes == 0
+					&& untainted > 0) {
+						probe(t);
+						t->nout_probes++;
+					}
+					list_replace(&f->head, &nf->head);
+					pos = &nf->head;
+					aoe_freetframe(f);
+					f = nf;
+					t = f->t;
+				}
+			} else if (untainted < 1) {
+				/* don't probe w/o other untainted aoetgts */
+				goto stop_probe;
+			} else if (tsince_hr(f) < t->taint * rto(d)) {
+				/* reprobe slowly when taint is high */
+				continue;
+			}
+		} else if (f->flags & FFL_PROBE) {
+stop_probe:		/* don't probe untainted aoetgts */
+			list_del(pos);
+			aoe_freetframe(f);
+			/* leaving d->kicked, because this is routine */
+			f->t->d->flags |= DEVFL_KICKME;
+			continue;
+		}
+		if (t->nout >= t->maxout)
+			continue;
+		list_del(pos);
+		t->nout++;
+		if (f->flags & FFL_PROBE)
+			t->nout_probes++;
+		since = tsince_hr(f);
+		f->waited += since;
+		f->waited_total += since;
+		resend(d, f);
+	}
+}
+
+/* An aoetgt accumulates demerits quickly, and successful
+ * probing redeems the aoetgt slowly.
+ */
+static void
+scorn(struct aoetgt *t)
+{
+	int n;
+
+	n = t->taint++;
+	t->taint += t->taint * 2;
+	if (n > t->taint)
+		t->taint = n;
+	if (t->taint > MAX_TAINT)
+		t->taint = MAX_TAINT;
+}
+
+static int
+count_targets(struct aoedev *d, int *untainted)
+{
+	int i, good;
+
+	for (i = good = 0; i < d->ntargets && d->targets[i]; ++i)
+		if (d->targets[i]->taint == 0)
+			good++;
+
+	if (untainted)
+		*untainted = good;
+	return i;
+}
+
+static void
+rexmit_timer(struct timer_list *timer)
+{
+	struct aoedev *d;
+	struct aoetgt *t;
+	struct aoeif *ifp;
+	struct frame *f;
+	struct list_head *head, *pos, *nx;
+	LIST_HEAD(flist);
+	register long timeout;
+	ulong flags, n;
+	int i;
+	int utgts;	/* number of aoetgt descriptors (not slots) */
+	int since;
+
+	d = from_timer(d, timer, timer);
+
+	spin_lock_irqsave(&d->lock, flags);
+
+	/* timeout based on observed timings and variations */
+	timeout = rto(d);
+
+	utgts = count_targets(d, NULL);
+
+	if (d->flags & DEVFL_TKILL) {
+		spin_unlock_irqrestore(&d->lock, flags);
+		return;
+	}
+
+	/* collect all frames to rexmit into flist */
+	for (i = 0; i < NFACTIVE; i++) {
+		head = &d->factive[i];
+		list_for_each_safe(pos, nx, head) {
+			f = list_entry(pos, struct frame, head);
+			if (tsince_hr(f) < timeout)
+				break;	/* end of expired frames */
+			/* move to flist for later processing */
+			list_move_tail(pos, &flist);
+		}
+	}
+
+	/* process expired frames */
+	while (!list_empty(&flist)) {
+		pos = flist.next;
+		f = list_entry(pos, struct frame, head);
+		since = tsince_hr(f);
+		n = f->waited_total + since;
+		n /= USEC_PER_SEC;
+		if (aoe_deadsecs
+		&& n > aoe_deadsecs
+		&& !(f->flags & FFL_PROBE)) {
+			/* Waited too long.  Device failure.
+			 * Hang all frames on first hash bucket for downdev
+			 * to clean up.
+			 */
+			list_splice(&flist, &d->factive[0]);
+			aoedev_downdev(d);
+			goto out;
+		}
+
+		t = f->t;
+		n = f->waited + since;
+		n /= USEC_PER_SEC;
+		if (aoe_deadsecs && utgts > 0
+		&& (n > aoe_deadsecs / utgts || n > HARD_SCORN_SECS))
+			scorn(t); /* avoid this target */
+
+		if (t->maxout != 1) {
+			t->ssthresh = t->maxout / 2;
+			t->maxout = 1;
+		}
+
+		if (f->flags & FFL_PROBE) {
+			t->nout_probes--;
+		} else {
+			ifp = getif(t, f->skb->dev);
+			if (ifp && ++ifp->lost > (t->nframes << 1)
+			&& (ifp != t->ifs || t->ifs[1].nd)) {
+				ejectif(t, ifp);
+				ifp = NULL;
+			}
+		}
+		list_move_tail(pos, &d->rexmitq);
+		t->nout--;
+	}
+	rexmit_deferred(d);
+
+out:
+	if ((d->flags & DEVFL_KICKME) && d->blkq) {
+		d->flags &= ~DEVFL_KICKME;
+		blk_mq_run_hw_queues(d->blkq, true);
+	}
+
+	d->timer.expires = jiffies + TIMERTICK;
+	add_timer(&d->timer);
+
+	spin_unlock_irqrestore(&d->lock, flags);
+}
+
+static void
+bufinit(struct buf *buf, struct request *rq, struct bio *bio)
+{
+	memset(buf, 0, sizeof(*buf));
+	buf->rq = rq;
+	buf->bio = bio;
+	buf->iter = bio->bi_iter;
+}
+
+static struct buf *
+nextbuf(struct aoedev *d)
+{
+	struct request *rq;
+	struct request_queue *q;
+	struct aoe_req *req;
+	struct buf *buf;
+	struct bio *bio;
+
+	q = d->blkq;
+	if (q == NULL)
+		return NULL;	/* initializing */
+	if (d->ip.buf)
+		return d->ip.buf;
+	rq = d->ip.rq;
+	if (rq == NULL) {
+		rq = list_first_entry_or_null(&d->rq_list, struct request,
+						queuelist);
+		if (rq == NULL)
+			return NULL;
+		list_del_init(&rq->queuelist);
+		blk_mq_start_request(rq);
+		d->ip.rq = rq;
+		d->ip.nxbio = rq->bio;
+
+		req = blk_mq_rq_to_pdu(rq);
+		req->nr_bios = 0;
+		__rq_for_each_bio(bio, rq)
+			req->nr_bios++;
+	}
+	buf = mempool_alloc(d->bufpool, GFP_ATOMIC);
+	if (buf == NULL) {
+		pr_err("aoe: nextbuf: unable to mempool_alloc!\n");
+		return NULL;
+	}
+	bio = d->ip.nxbio;
+	bufinit(buf, rq, bio);
+	bio = bio->bi_next;
+	d->ip.nxbio = bio;
+	if (bio == NULL)
+		d->ip.rq = NULL;
+	return d->ip.buf = buf;
+}
+
+/* enters with d->lock held */
+void
+aoecmd_work(struct aoedev *d)
+{
+	rexmit_deferred(d);
+	while (aoecmd_ata_rw(d))
+		;
+}
+
+/* this function performs work that has been deferred until sleeping is OK
+ */
+void
+aoecmd_sleepwork(struct work_struct *work)
+{
+	struct aoedev *d = container_of(work, struct aoedev, work);
+
+	if (d->flags & DEVFL_GDALLOC)
+		aoeblk_gdalloc(d);
+
+	if (d->flags & DEVFL_NEWSIZE) {
+		set_capacity_and_notify(d->gd, d->ssize);
+
+		spin_lock_irq(&d->lock);
+		d->flags |= DEVFL_UP;
+		d->flags &= ~DEVFL_NEWSIZE;
+		spin_unlock_irq(&d->lock);
+	}
+}
+
+static void
+ata_ident_fixstring(u16 *id, int ns)
+{
+	u16 s;
+
+	while (ns-- > 0) {
+		s = *id;
+		*id++ = s >> 8 | s << 8;
+	}
+}
+
+static void
+ataid_complete(struct aoedev *d, struct aoetgt *t, unsigned char *id)
+{
+	u64 ssize;
+	u16 n;
+
+	/* word 83: command set supported */
+	n = get_unaligned_le16(&id[83 << 1]);
+
+	/* word 86: command set/feature enabled */
+	n |= get_unaligned_le16(&id[86 << 1]);
+
+	if (n & (1<<10)) {	/* bit 10: LBA 48 */
+		d->flags |= DEVFL_EXT;
+
+		/* word 100: number lba48 sectors */
+		ssize = get_unaligned_le64(&id[100 << 1]);
+
+		/* set as in ide-disk.c:init_idedisk_capacity */
+		d->geo.cylinders = ssize;
+		d->geo.cylinders /= (255 * 63);
+		d->geo.heads = 255;
+		d->geo.sectors = 63;
+	} else {
+		d->flags &= ~DEVFL_EXT;
+
+		/* number lba28 sectors */
+		ssize = get_unaligned_le32(&id[60 << 1]);
+
+		/* NOTE: obsolete in ATA 6 */
+		d->geo.cylinders = get_unaligned_le16(&id[54 << 1]);
+		d->geo.heads = get_unaligned_le16(&id[55 << 1]);
+		d->geo.sectors = get_unaligned_le16(&id[56 << 1]);
+	}
+
+	ata_ident_fixstring((u16 *) &id[10<<1], 10);	/* serial */
+	ata_ident_fixstring((u16 *) &id[23<<1], 4);	/* firmware */
+	ata_ident_fixstring((u16 *) &id[27<<1], 20);	/* model */
+	memcpy(d->ident, id, sizeof(d->ident));
+
+	if (d->ssize != ssize)
+		printk(KERN_INFO
+			"aoe: %pm e%ld.%d v%04x has %llu sectors\n",
+			t->addr,
+			d->aoemajor, d->aoeminor,
+			d->fw_ver, (long long)ssize);
+	d->ssize = ssize;
+	d->geo.start = 0;
+	if (d->flags & (DEVFL_GDALLOC|DEVFL_NEWSIZE))
+		return;
+	if (d->gd != NULL)
+		d->flags |= DEVFL_NEWSIZE;
+	else
+		d->flags |= DEVFL_GDALLOC;
+	queue_work(aoe_wq, &d->work);
+}
+
+static void
+calc_rttavg(struct aoedev *d, struct aoetgt *t, int rtt)
+{
+	register long n;
+
+	n = rtt;
+
+	/* cf. Congestion Avoidance and Control, Jacobson & Karels, 1988 */
+	n -= d->rttavg >> RTTSCALE;
+	d->rttavg += n;
+	if (n < 0)
+		n = -n;
+	n -= d->rttdev >> RTTDSCALE;
+	d->rttdev += n;
+
+	if (!t || t->maxout >= t->nframes)
+		return;
+	if (t->maxout < t->ssthresh)
+		t->maxout += 1;
+	else if (t->nout == t->maxout && t->next_cwnd-- == 0) {
+		t->maxout += 1;
+		t->next_cwnd = t->maxout;
+	}
+}
+
+static struct aoetgt *
+gettgt(struct aoedev *d, char *addr)
+{
+	struct aoetgt **t, **e;
+
+	t = d->targets;
+	e = t + d->ntargets;
+	for (; t < e && *t; t++)
+		if (memcmp((*t)->addr, addr, sizeof((*t)->addr)) == 0)
+			return *t;
+	return NULL;
+}
+
+static void
+bvcpy(struct sk_buff *skb, struct bio *bio, struct bvec_iter iter, long cnt)
+{
+	int soff = 0;
+	struct bio_vec bv;
+
+	iter.bi_size = cnt;
+
+	__bio_for_each_segment(bv, bio, iter, iter) {
+		char *p = bvec_kmap_local(&bv);
+		skb_copy_bits(skb, soff, p, bv.bv_len);
+		kunmap_local(p);
+		soff += bv.bv_len;
+	}
+}
+
+void
+aoe_end_request(struct aoedev *d, struct request *rq, int fastfail)
+{
+	struct bio *bio;
+	int bok;
+	struct request_queue *q;
+	blk_status_t err = BLK_STS_OK;
+
+	q = d->blkq;
+	if (rq == d->ip.rq)
+		d->ip.rq = NULL;
+	do {
+		bio = rq->bio;
+		bok = !fastfail && !bio->bi_status;
+		if (!bok)
+			err = BLK_STS_IOERR;
+	} while (blk_update_request(rq, bok ? BLK_STS_OK : BLK_STS_IOERR, bio->bi_iter.bi_size));
+
+	__blk_mq_end_request(rq, err);
+
+	/* cf. https://lore.kernel.org/lkml/20061031071040.GS14055@kernel.dk/ */
+	if (!fastfail)
+		blk_mq_run_hw_queues(q, true);
+}
+
+static void
+aoe_end_buf(struct aoedev *d, struct buf *buf)
+{
+	struct request *rq = buf->rq;
+	struct aoe_req *req = blk_mq_rq_to_pdu(rq);
+
+	if (buf == d->ip.buf)
+		d->ip.buf = NULL;
+	mempool_free(buf, d->bufpool);
+	if (--req->nr_bios == 0)
+		aoe_end_request(d, rq, 0);
+}
+
+static void
+ktiocomplete(struct frame *f)
+{
+	struct aoe_hdr *hin, *hout;
+	struct aoe_atahdr *ahin, *ahout;
+	struct buf *buf;
+	struct sk_buff *skb;
+	struct aoetgt *t;
+	struct aoeif *ifp;
+	struct aoedev *d;
+	long n;
+	int untainted;
+
+	if (f == NULL)
+		return;
+
+	t = f->t;
+	d = t->d;
+	skb = f->r_skb;
+	buf = f->buf;
+	if (f->flags & FFL_PROBE)
+		goto out;
+	if (!skb)		/* just fail the buf. */
+		goto noskb;
+
+	hout = (struct aoe_hdr *) skb_mac_header(f->skb);
+	ahout = (struct aoe_atahdr *) (hout+1);
+
+	hin = (struct aoe_hdr *) skb->data;
+	skb_pull(skb, sizeof(*hin));
+	ahin = (struct aoe_atahdr *) skb->data;
+	skb_pull(skb, sizeof(*ahin));
+	if (ahin->cmdstat & 0xa9) {	/* these bits cleared on success */
+		pr_err("aoe: ata error cmd=%2.2Xh stat=%2.2Xh from e%ld.%d\n",
+			ahout->cmdstat, ahin->cmdstat,
+			d->aoemajor, d->aoeminor);
+noskb:		if (buf)
+			buf->bio->bi_status = BLK_STS_IOERR;
+		goto out;
+	}
+
+	n = ahout->scnt << 9;
+	switch (ahout->cmdstat) {
+	case ATA_CMD_PIO_READ:
+	case ATA_CMD_PIO_READ_EXT:
+		if (skb->len < n) {
+			pr_err("%s e%ld.%d.  skb->len=%d need=%ld\n",
+				"aoe: runt data size in read from",
+				(long) d->aoemajor, d->aoeminor,
+			       skb->len, n);
+			buf->bio->bi_status = BLK_STS_IOERR;
+			break;
+		}
+		if (n > f->iter.bi_size) {
+			pr_err_ratelimited("%s e%ld.%d.  bytes=%ld need=%u\n",
+				"aoe: too-large data size in read from",
+				(long) d->aoemajor, d->aoeminor,
+				n, f->iter.bi_size);
+			buf->bio->bi_status = BLK_STS_IOERR;
+			break;
+		}
+		bvcpy(skb, f->buf->bio, f->iter, n);
+		fallthrough;
+	case ATA_CMD_PIO_WRITE:
+	case ATA_CMD_PIO_WRITE_EXT:
+		spin_lock_irq(&d->lock);
+		ifp = getif(t, skb->dev);
+		if (ifp)
+			ifp->lost = 0;
+		spin_unlock_irq(&d->lock);
+		break;
+	case ATA_CMD_ID_ATA:
+		if (skb->len < 512) {
+			pr_info("%s e%ld.%d.  skb->len=%d need=512\n",
+				"aoe: runt data size in ataid from",
+				(long) d->aoemajor, d->aoeminor,
+				skb->len);
+			break;
+		}
+		if (skb_linearize(skb))
+			break;
+		spin_lock_irq(&d->lock);
+		ataid_complete(d, t, skb->data);
+		spin_unlock_irq(&d->lock);
+		break;
+	default:
+		pr_info("aoe: unrecognized ata command %2.2Xh for %d.%d\n",
+			ahout->cmdstat,
+			be16_to_cpu(get_unaligned(&hin->major)),
+			hin->minor);
+	}
+out:
+	spin_lock_irq(&d->lock);
+	if (t->taint > 0
+	&& --t->taint > 0
+	&& t->nout_probes == 0) {
+		count_targets(d, &untainted);
+		if (untainted > 0) {
+			probe(t);
+			t->nout_probes++;
+		}
+	}
+
+	aoe_freetframe(f);
+
+	if (buf && --buf->nframesout == 0 && buf->iter.bi_size == 0)
+		aoe_end_buf(d, buf);
+
+	spin_unlock_irq(&d->lock);
+	aoedev_put(d);
+	dev_kfree_skb(skb);
+}
+
+/* Enters with iocq.lock held.
+ * Returns true iff responses needing processing remain.
+ */
+static int
+ktio(int id)
+{
+	struct frame *f;
+	struct list_head *pos;
+	int i;
+	int actual_id;
+
+	for (i = 0; ; ++i) {
+		if (i == MAXIOC)
+			return 1;
+		if (list_empty(&iocq[id].head))
+			return 0;
+		pos = iocq[id].head.next;
+		list_del(pos);
+		f = list_entry(pos, struct frame, head);
+		spin_unlock_irq(&iocq[id].lock);
+		ktiocomplete(f);
+
+		/* Figure out if extra threads are required. */
+		actual_id = f->t->d->aoeminor % ncpus;
+
+		if (!kts[actual_id].active) {
+			BUG_ON(id != 0);
+			mutex_lock(&ktio_spawn_lock);
+			if (!kts[actual_id].active
+				&& aoe_ktstart(&kts[actual_id]) == 0)
+				kts[actual_id].active = 1;
+			mutex_unlock(&ktio_spawn_lock);
+		}
+		spin_lock_irq(&iocq[id].lock);
+	}
+}
+
+static int
+kthread(void *vp)
+{
+	struct ktstate *k;
+	DECLARE_WAITQUEUE(wait, current);
+	int more;
+
+	k = vp;
+	current->flags |= PF_NOFREEZE;
+	set_user_nice(current, -10);
+	complete(&k->rendez);	/* tell spawner we're running */
+	do {
+		spin_lock_irq(k->lock);
+		more = k->fn(k->id);
+		if (!more) {
+			add_wait_queue(k->waitq, &wait);
+			__set_current_state(TASK_INTERRUPTIBLE);
+		}
+		spin_unlock_irq(k->lock);
+		if (!more) {
+			schedule();
+			remove_wait_queue(k->waitq, &wait);
+		} else
+			cond_resched();
+	} while (!kthread_should_stop());
+	complete(&k->rendez);	/* tell spawner we're stopping */
+	return 0;
+}
+
+void
+aoe_ktstop(struct ktstate *k)
+{
+	kthread_stop(k->task);
+	wait_for_completion(&k->rendez);
+}
+
+int
+aoe_ktstart(struct ktstate *k)
+{
+	struct task_struct *task;
+
+	init_completion(&k->rendez);
+	task = kthread_run(kthread, k, "%s", k->name);
+	if (task == NULL || IS_ERR(task))
+		return -ENOMEM;
+	k->task = task;
+	wait_for_completion(&k->rendez); /* allow kthread to start */
+	init_completion(&k->rendez);	/* for waiting for exit later */
+	return 0;
+}
+
+/* pass it off to kthreads for processing */
+static void
+ktcomplete(struct frame *f, struct sk_buff *skb)
+{
+	int id;
+	ulong flags;
+
+	f->r_skb = skb;
+	id = f->t->d->aoeminor % ncpus;
+	spin_lock_irqsave(&iocq[id].lock, flags);
+	if (!kts[id].active) {
+		spin_unlock_irqrestore(&iocq[id].lock, flags);
+		/* The thread with id has not been spawned yet,
+		 * so delegate the work to the main thread and
+		 * try spawning a new thread.
+		 */
+		id = 0;
+		spin_lock_irqsave(&iocq[id].lock, flags);
+	}
+	list_add_tail(&f->head, &iocq[id].head);
+	spin_unlock_irqrestore(&iocq[id].lock, flags);
+	wake_up(&ktiowq[id]);
+}
+
+struct sk_buff *
+aoecmd_ata_rsp(struct sk_buff *skb)
+{
+	struct aoedev *d;
+	struct aoe_hdr *h;
+	struct frame *f;
+	u32 n;
+	ulong flags;
+	char ebuf[128];
+	u16 aoemajor;
+
+	h = (struct aoe_hdr *) skb->data;
+	aoemajor = be16_to_cpu(get_unaligned(&h->major));
+	d = aoedev_by_aoeaddr(aoemajor, h->minor, 0);
+	if (d == NULL) {
+		snprintf(ebuf, sizeof ebuf, "aoecmd_ata_rsp: ata response "
+			"for unknown device %d.%d\n",
+			aoemajor, h->minor);
+		aoechr_error(ebuf);
+		return skb;
+	}
+
+	spin_lock_irqsave(&d->lock, flags);
+
+	n = be32_to_cpu(get_unaligned(&h->tag));
+	f = getframe(d, n);
+	if (f) {
+		calc_rttavg(d, f->t, tsince_hr(f));
+		f->t->nout--;
+		if (f->flags & FFL_PROBE)
+			f->t->nout_probes--;
+	} else {
+		f = getframe_deferred(d, n);
+		if (f) {
+			calc_rttavg(d, NULL, tsince_hr(f));
+		} else {
+			calc_rttavg(d, NULL, tsince(n));
+			spin_unlock_irqrestore(&d->lock, flags);
+			aoedev_put(d);
+			snprintf(ebuf, sizeof(ebuf),
+				 "%15s e%d.%d    tag=%08x@%08lx s=%pm d=%pm\n",
+				 "unexpected rsp",
+				 get_unaligned_be16(&h->major),
+				 h->minor,
+				 get_unaligned_be32(&h->tag),
+				 jiffies,
+				 h->src,
+				 h->dst);
+			aoechr_error(ebuf);
+			return skb;
+		}
+	}
+	aoecmd_work(d);
+
+	spin_unlock_irqrestore(&d->lock, flags);
+
+	ktcomplete(f, skb);
+
+	/*
+	 * Note here that we do not perform an aoedev_put, as we are
+	 * leaving this reference for the ktio to release.
+	 */
+	return NULL;
+}
+
+void
+aoecmd_cfg(ushort aoemajor, unsigned char aoeminor)
+{
+	struct sk_buff_head queue;
+
+	__skb_queue_head_init(&queue);
+	aoecmd_cfg_pkts(aoemajor, aoeminor, &queue);
+	aoenet_xmit(&queue);
+}
+
+struct sk_buff *
+aoecmd_ata_id(struct aoedev *d)
+{
+	struct aoe_hdr *h;
+	struct aoe_atahdr *ah;
+	struct frame *f;
+	struct sk_buff *skb;
+	struct aoetgt *t;
+
+	f = newframe(d);
+	if (f == NULL)
+		return NULL;
+
+	t = *d->tgt;
+
+	/* initialize the headers & frame */
+	skb = f->skb;
+	h = (struct aoe_hdr *) skb_mac_header(skb);
+	ah = (struct aoe_atahdr *) (h+1);
+	skb_put(skb, sizeof *h + sizeof *ah);
+	memset(h, 0, skb->len);
+	f->tag = aoehdr_atainit(d, t, h);
+	fhash(f);
+	t->nout++;
+	f->waited = 0;
+	f->waited_total = 0;
+
+	/* set up ata header */
+	ah->scnt = 1;
+	ah->cmdstat = ATA_CMD_ID_ATA;
+	ah->lba3 = 0xa0;
+
+	skb->dev = t->ifp->nd;
+
+	d->rttavg = RTTAVG_INIT;
+	d->rttdev = RTTDEV_INIT;
+	d->timer.function = rexmit_timer;
+
+	skb = skb_clone(skb, GFP_ATOMIC);
+	if (skb)
+		f->sent = ktime_get();
+
+	return skb;
+}
+
+static struct aoetgt **
+grow_targets(struct aoedev *d)
+{
+	ulong oldn, newn;
+	struct aoetgt **tt;
+
+	oldn = d->ntargets;
+	newn = oldn * 2;
+	tt = kcalloc(newn, sizeof(*d->targets), GFP_ATOMIC);
+	if (!tt)
+		return NULL;
+	memmove(tt, d->targets, sizeof(*d->targets) * oldn);
+	d->tgt = tt + (d->tgt - d->targets);
+	kfree(d->targets);
+	d->targets = tt;
+	d->ntargets = newn;
+
+	return &d->targets[oldn];
+}
+
+static struct aoetgt *
+addtgt(struct aoedev *d, char *addr, ulong nframes)
+{
+	struct aoetgt *t, **tt, **te;
+
+	tt = d->targets;
+	te = tt + d->ntargets;
+	for (; tt < te && *tt; tt++)
+		;
+
+	if (tt == te) {
+		tt = grow_targets(d);
+		if (!tt)
+			goto nomem;
+	}
+	t = kzalloc(sizeof(*t), GFP_ATOMIC);
+	if (!t)
+		goto nomem;
+	t->nframes = nframes;
+	t->d = d;
+	memcpy(t->addr, addr, sizeof t->addr);
+	t->ifp = t->ifs;
+	aoecmd_wreset(t);
+	t->maxout = t->nframes / 2;
+	INIT_LIST_HEAD(&t->ffree);
+	return *tt = t;
+
+ nomem:
+	pr_info("aoe: cannot allocate memory to add target\n");
+	return NULL;
+}
+
+static void
+setdbcnt(struct aoedev *d)
+{
+	struct aoetgt **t, **e;
+	int bcnt = 0;
+
+	t = d->targets;
+	e = t + d->ntargets;
+	for (; t < e && *t; t++)
+		if (bcnt == 0 || bcnt > (*t)->minbcnt)
+			bcnt = (*t)->minbcnt;
+	if (bcnt != d->maxbcnt) {
+		d->maxbcnt = bcnt;
+		pr_info("aoe: e%ld.%d: setting %d byte data frames\n",
+			d->aoemajor, d->aoeminor, bcnt);
+	}
+}
+
+static void
+setifbcnt(struct aoetgt *t, struct net_device *nd, int bcnt)
+{
+	struct aoedev *d;
+	struct aoeif *p, *e;
+	int minbcnt;
+
+	d = t->d;
+	minbcnt = bcnt;
+	p = t->ifs;
+	e = p + NAOEIFS;
+	for (; p < e; p++) {
+		if (p->nd == NULL)
+			break;		/* end of the valid interfaces */
+		if (p->nd == nd) {
+			p->bcnt = bcnt;	/* we're updating */
+			nd = NULL;
+		} else if (minbcnt > p->bcnt)
+			minbcnt = p->bcnt; /* find the min interface */
+	}
+	if (nd) {
+		if (p == e) {
+			pr_err("aoe: device setifbcnt failure; too many interfaces.\n");
+			return;
+		}
+		dev_hold(nd);
+		p->nd = nd;
+		p->bcnt = bcnt;
+	}
+	t->minbcnt = minbcnt;
+	setdbcnt(d);
+}
+
+void
+aoecmd_cfg_rsp(struct sk_buff *skb)
+{
+	struct aoedev *d;
+	struct aoe_hdr *h;
+	struct aoe_cfghdr *ch;
+	struct aoetgt *t;
+	ulong flags, aoemajor;
+	struct sk_buff *sl;
+	struct sk_buff_head queue;
+	u16 n;
+
+	sl = NULL;
+	h = (struct aoe_hdr *) skb_mac_header(skb);
+	ch = (struct aoe_cfghdr *) (h+1);
+
+	/*
+	 * Enough people have their dip switches set backwards to
+	 * warrant a loud message for this special case.
+	 */
+	aoemajor = get_unaligned_be16(&h->major);
+	if (aoemajor == 0xfff) {
+		printk(KERN_ERR "aoe: Warning: shelf address is all ones.  "
+			"Check shelf dip switches.\n");
+		return;
+	}
+	if (aoemajor == 0xffff) {
+		pr_info("aoe: e%ld.%d: broadcast shelf number invalid\n",
+			aoemajor, (int) h->minor);
+		return;
+	}
+	if (h->minor == 0xff) {
+		pr_info("aoe: e%ld.%d: broadcast slot number invalid\n",
+			aoemajor, (int) h->minor);
+		return;
+	}
+
+	n = be16_to_cpu(ch->bufcnt);
+	if (n > aoe_maxout)	/* keep it reasonable */
+		n = aoe_maxout;
+
+	d = aoedev_by_aoeaddr(aoemajor, h->minor, 1);
+	if (d == NULL) {
+		pr_info("aoe: device allocation failure\n");
+		return;
+	}
+
+	spin_lock_irqsave(&d->lock, flags);
+
+	t = gettgt(d, h->src);
+	if (t) {
+		t->nframes = n;
+		if (n < t->maxout)
+			aoecmd_wreset(t);
+	} else {
+		t = addtgt(d, h->src, n);
+		if (!t)
+			goto bail;
+	}
+	n = skb->dev->mtu;
+	n -= sizeof(struct aoe_hdr) + sizeof(struct aoe_atahdr);
+	n /= 512;
+	if (n > ch->scnt)
+		n = ch->scnt;
+	n = n ? n * 512 : DEFAULTBCNT;
+	setifbcnt(t, skb->dev, n);
+
+	/* don't change users' perspective */
+	if (d->nopen == 0) {
+		d->fw_ver = be16_to_cpu(ch->fwver);
+		sl = aoecmd_ata_id(d);
+	}
+bail:
+	spin_unlock_irqrestore(&d->lock, flags);
+	aoedev_put(d);
+	if (sl) {
+		__skb_queue_head_init(&queue);
+		__skb_queue_tail(&queue, sl);
+		aoenet_xmit(&queue);
+	}
+}
+
+void
+aoecmd_wreset(struct aoetgt *t)
+{
+	t->maxout = 1;
+	t->ssthresh = t->nframes / 2;
+	t->next_cwnd = t->nframes;
+}
+
+void
+aoecmd_cleanslate(struct aoedev *d)
+{
+	struct aoetgt **t, **te;
+
+	d->rttavg = RTTAVG_INIT;
+	d->rttdev = RTTDEV_INIT;
+	d->maxbcnt = 0;
+
+	t = d->targets;
+	te = t + d->ntargets;
+	for (; t < te && *t; t++)
+		aoecmd_wreset(*t);
+}
+
+void
+aoe_failbuf(struct aoedev *d, struct buf *buf)
+{
+	if (buf == NULL)
+		return;
+	buf->iter.bi_size = 0;
+	buf->bio->bi_status = BLK_STS_IOERR;
+	if (buf->nframesout == 0)
+		aoe_end_buf(d, buf);
+}
+
+void
+aoe_flush_iocq(void)
+{
+	int i;
+
+	for (i = 0; i < ncpus; i++) {
+		if (kts[i].active)
+			aoe_flush_iocq_by_index(i);
+	}
+}
+
+void
+aoe_flush_iocq_by_index(int id)
+{
+	struct frame *f;
+	struct aoedev *d;
+	LIST_HEAD(flist);
+	struct list_head *pos;
+	struct sk_buff *skb;
+	ulong flags;
+
+	spin_lock_irqsave(&iocq[id].lock, flags);
+	list_splice_init(&iocq[id].head, &flist);
+	spin_unlock_irqrestore(&iocq[id].lock, flags);
+	while (!list_empty(&flist)) {
+		pos = flist.next;
+		list_del(pos);
+		f = list_entry(pos, struct frame, head);
+		d = f->t->d;
+		skb = f->r_skb;
+		spin_lock_irqsave(&d->lock, flags);
+		if (f->buf) {
+			f->buf->nframesout--;
+			aoe_failbuf(d, f->buf);
+		}
+		aoe_freetframe(f);
+		spin_unlock_irqrestore(&d->lock, flags);
+		dev_kfree_skb(skb);
+		aoedev_put(d);
+	}
+}
+
+int __init
+aoecmd_init(void)
+{
+	void *p;
+	int i;
+	int ret;
+
+	/* get_zeroed_page returns page with ref count 1 */
+	p = (void *) get_zeroed_page(GFP_KERNEL);
+	if (!p)
+		return -ENOMEM;
+	empty_page = virt_to_page(p);
+
+	ncpus = num_online_cpus();
+
+	iocq = kcalloc(ncpus, sizeof(struct iocq_ktio), GFP_KERNEL);
+	if (!iocq)
+		return -ENOMEM;
+
+	kts = kcalloc(ncpus, sizeof(struct ktstate), GFP_KERNEL);
+	if (!kts) {
+		ret = -ENOMEM;
+		goto kts_fail;
+	}
+
+	ktiowq = kcalloc(ncpus, sizeof(wait_queue_head_t), GFP_KERNEL);
+	if (!ktiowq) {
+		ret = -ENOMEM;
+		goto ktiowq_fail;
+	}
+
+	for (i = 0; i < ncpus; i++) {
+		INIT_LIST_HEAD(&iocq[i].head);
+		spin_lock_init(&iocq[i].lock);
+		init_waitqueue_head(&ktiowq[i]);
+		snprintf(kts[i].name, sizeof(kts[i].name), "aoe_ktio%d", i);
+		kts[i].fn = ktio;
+		kts[i].waitq = &ktiowq[i];
+		kts[i].lock = &iocq[i].lock;
+		kts[i].id = i;
+		kts[i].active = 0;
+	}
+	kts[0].active = 1;
+	if (aoe_ktstart(&kts[0])) {
+		ret = -ENOMEM;
+		goto ktstart_fail;
+	}
+	return 0;
+
+ktstart_fail:
+	kfree(ktiowq);
+ktiowq_fail:
+	kfree(kts);
+kts_fail:
+	kfree(iocq);
+
+	return ret;
+}
+
+void
+aoecmd_exit(void)
+{
+	int i;
+
+	for (i = 0; i < ncpus; i++)
+		if (kts[i].active)
+			aoe_ktstop(&kts[i]);
+
+	aoe_flush_iocq();
+
+	/* Free up the iocq and thread speicific configuration
+	* allocated during startup.
+	*/
+	kfree(iocq);
+	kfree(kts);
+	kfree(ktiowq);
+
+	free_page((unsigned long) page_address(empty_page));
+	empty_page = NULL;
+}