/* Copyright (c) 2007 Coraid, Inc.  See COPYING for GPL terms. */
/*
 * aoecmd.c
 * Filesystem request handling methods
 */

#include <linux/hdreg.h>
#include <linux/blkdev.h>
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <linux/genhd.h>
#include <linux/moduleparam.h>
#include <net/net_namespace.h>
#include <asm/unaligned.h>
#include "aoe.h"

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 = 16;
module_param(aoe_maxout, int, 0644);
MODULE_PARM_DESC(aoe_maxout,
        "Only aoe_maxout outstanding packets for every MAC on eX.Y.");

static struct sk_buff *
new_skb(ulong len)
{
        struct sk_buff *skb;

        skb = alloc_skb(len, GFP_ATOMIC);
        if (skb) {
                skb_reset_mac_header(skb);
                skb_reset_network_header(skb);
                skb->protocol = __constant_htons(ETH_P_AOE);
                skb->priority = 0;
                skb->next = skb->prev = NULL;

                /* tell the network layer not to perform IP checksums
                 * or to get the NIC to do it
                 */
                skb->ip_summed = CHECKSUM_NONE;
        }
        return skb;
}

static struct frame *
getframe(struct aoetgt *t, int tag)
{
        struct frame *f, *e;

        f = t->frames;
        e = f + t->nframes;
        for (; f<e; f++)
                if (f->tag == tag)
                        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 aoetgt *t)
{
        register ulong n;

        n = jiffies & 0xffff;
        return n |= (++t->lasttag & 0x7fff) << 16;
}

static int
aoehdr_atainit(struct aoedev *d, struct aoetgt *t, struct aoe_hdr *h)
{
        u32 host_tag = newtag(t);

        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 void
ifrotate(struct aoetgt *t)
{
        t->ifp++;
        if (t->ifp >= &t->ifs[NAOEIFS] || t->ifp->nd == NULL)
                t->ifp = t->ifs;
        if (t->ifp->nd == NULL) {
                printk(KERN_INFO "aoe: no interface to rotate to\n");
                BUG();
        }
}

static void
skb_pool_put(struct aoedev *d, struct sk_buff *skb)
{
        if (!d->skbpool_hd)
                d->skbpool_hd = skb;
        else
                d->skbpool_tl->next = skb;
        d->skbpool_tl = skb;
}

static struct sk_buff *
skb_pool_get(struct aoedev *d)
{
        struct sk_buff *skb;

        skb = d->skbpool_hd;
        if (skb && atomic_read(&skb_shinfo(skb)->dataref) == 1) {
                d->skbpool_hd = skb->next;
                skb->next = NULL;
                return skb;
        }
        if (d->nskbpool < NSKBPOOLMAX
        && (skb = new_skb(ETH_ZLEN))) {
                d->nskbpool++;
                return skb;
        }
        return NULL;
}

/* freeframe is where we do our load balancing so it's a little hairy. */
static struct frame *
freeframe(struct aoedev *d)
{
        struct frame *f, *e, *rf;
        struct aoetgt **t;
        struct sk_buff *skb;

        if (d->targets[0] == NULL) {    /* shouldn't happen, but I'm paranoid */
                printk(KERN_ERR "aoe: NULL TARGETS!\n");
                return NULL;
        }
        t = d->tgt;
        t++;
        if (t >= &d->targets[NTARGETS] || !*t)
                t = d->targets;
        for (;;) {
                if ((*t)->nout < (*t)->maxout
                && t != d->htgt
                && (*t)->ifp->nd) {
                        rf = NULL;
                        f = (*t)->frames;
                        e = f + (*t)->nframes;
                        for (; f < e; f++) {
                                if (f->tag != FREETAG)
                                        continue;
                                skb = f->skb;
                                if (!skb
                                && !(f->skb = skb = new_skb(ETH_ZLEN)))
                                        continue;
                                if (atomic_read(&skb_shinfo(skb)->dataref)
                                        != 1) {
                                        if (!rf)
                                                rf = f;
                                        continue;
                                }
gotone:                         skb_shinfo(skb)->nr_frags = skb->data_len = 0;
                                skb_trim(skb, 0);
                                d->tgt = t;
                                ifrotate(*t);
                                return f;
                        }
                        /* Work can be done, but the network layer is
                           holding our precious packets.  Try to grab
                           one from the pool. */
                        f = rf;
                        if (f == NULL) {        /* more paranoia */
                                printk(KERN_ERR
                                        "aoe: freeframe: %s.\n",
                                        "unexpected null rf");
                                d->flags |= DEVFL_KICKME;
                                return NULL;
                        }
                        skb = skb_pool_get(d);
                        if (skb) {
                                skb_pool_put(d, f->skb);
                                f->skb = skb;
                                goto gotone;
                        }
                        (*t)->dataref++;
                        if ((*t)->nout == 0)
                                d->flags |= DEVFL_KICKME;
                }
                if (t == d->tgt)        /* we've looped and found nada */
                        break;
                t++;
                if (t >= &d->targets[NTARGETS] || !*t)
                        t = d->targets;
        }
        return NULL;
}

static int
aoecmd_ata_rw(struct aoedev *d)
{
        struct frame *f;
        struct aoe_hdr *h;
        struct aoe_atahdr *ah;
        struct buf *buf;
        struct bio_vec *bv;
        struct aoetgt *t;
        struct sk_buff *skb;
        ulong bcnt;
        char writebit, extbit;

        writebit = 0x10;
        extbit = 0x4;

        f = freeframe(d);
        if (f == NULL)
                return 0;
        t = *d->tgt;
        buf = d->inprocess;
        bv = buf->bv;
        bcnt = t->ifp->maxbcnt;
        if (bcnt == 0)
                bcnt = DEFAULTBCNT;
        if (bcnt > buf->bv_resid)
                bcnt = buf->bv_resid;
        /* 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);
        t->nout++;
        f->waited = 0;
        f->buf = buf;
        f->bufaddr = page_address(bv->bv_page) + buf->bv_off;
        f->bcnt = bcnt;
        f->lba = buf->sector;

        /* set up ata header */
        ah->scnt = bcnt >> 9;
        put_lba(ah, buf->sector);
        if (d->flags & DEVFL_EXT) {
                ah->aflags |= AOEAFL_EXT;
        } else {
                extbit = 0;
                ah->lba3 &= 0x0f;
                ah->lba3 |= 0xe0;       /* LBA bit + obsolete 0xa0 */
        }
        if (bio_data_dir(buf->bio) == WRITE) {
                skb_fill_page_desc(skb, 0, bv->bv_page, buf->bv_off, bcnt);
                ah->aflags |= AOEAFL_WRITE;
                skb->len += bcnt;
                skb->data_len = bcnt;
                t->wpkts++;
        } else {
                t->rpkts++;
                writebit = 0;
        }

        ah->cmdstat = WIN_READ | writebit | extbit;

        /* mark all tracking fields and load out */
        buf->nframesout += 1;
        buf->bv_off += bcnt;
        buf->bv_resid -= bcnt;
        buf->resid -= bcnt;
        buf->sector += bcnt >> 9;
        if (buf->resid == 0) {
                d->inprocess = NULL;
        } else if (buf->bv_resid == 0) {
                buf->bv = ++bv;
                buf->bv_resid = bv->bv_len;
                WARN_ON(buf->bv_resid == 0);
                buf->bv_off = bv->bv_offset;
        }

        skb->dev = t->ifp->nd;
        skb = skb_clone(skb, GFP_ATOMIC);
        if (skb) {
                if (d->sendq_hd)
                        d->sendq_tl->next = skb;
                else
                        d->sendq_hd = skb;
                d->sendq_tl = skb;
        }
        return 1;
}

/* some callers cannot sleep, and they can call this function,
 * transmitting the packets later, when interrupts are on
 */
static struct sk_buff *
aoecmd_cfg_pkts(ushort aoemajor, unsigned char aoeminor, struct sk_buff **tail)
{
        struct aoe_hdr *h;
        struct aoe_cfghdr *ch;
        struct sk_buff *skb, *sl, *sl_tail;
        struct net_device *ifp;

        sl = sl_tail = NULL;

        read_lock(&dev_base_lock);
        for_each_netdev(&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;
                if (sl_tail == NULL)
                        sl_tail = 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;

                skb->next = sl;
                sl = skb;
cont:
                dev_put(ifp);
        }
        read_unlock(&dev_base_lock);

        if (tail != NULL)
                *tail = sl_tail;
        return sl;
}

static void
resend(struct aoedev *d, struct aoetgt *t, struct frame *f)
{
        struct sk_buff *skb;
        struct aoe_hdr *h;
        struct aoe_atahdr *ah;
        char buf[128];
        u32 n;

        ifrotate(t);
        n = newtag(t);
        skb = f->skb;
        h = (struct aoe_hdr *) skb_mac_header(skb);
        ah = (struct aoe_atahdr *) (h+1);

        snprintf(buf, sizeof buf,
                "%15s e%ld.%d oldtag=%08x@%08lx newtag=%08x "
                "s=%012llx d=%012llx nout=%d\n",
                "retransmit", d->aoemajor, d->aoeminor, f->tag, jiffies, n,
                mac_addr(h->src),
                mac_addr(h->dst), t->nout);
        aoechr_error(buf);

        f->tag = n;
        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);

        switch (ah->cmdstat) {
        default:
                break;
        case WIN_READ:
        case WIN_READ_EXT:
        case WIN_WRITE:
        case WIN_WRITE_EXT:
                put_lba(ah, f->lba);

                n = f->bcnt;
                if (n > DEFAULTBCNT)
                        n = DEFAULTBCNT;
                ah->scnt = n >> 9;
                if (ah->aflags & AOEAFL_WRITE) {
                        skb_fill_page_desc(skb, 0, virt_to_page(f->bufaddr),
                                offset_in_page(f->bufaddr), n);
                        skb->len = sizeof *h + sizeof *ah + n;
                        skb->data_len = n;
                }
        }
        skb->dev = t->ifp->nd;
        skb = skb_clone(skb, GFP_ATOMIC);
        if (skb == NULL)
                return;
        if (d->sendq_hd)
                d->sendq_tl->next = skb;
        else
                d->sendq_hd = skb;
        d->sendq_tl = skb;
}

static int
tsince(int tag)
{
        int n;

        n = jiffies & 0xffff;
        n -= tag & 0xffff;
        if (n < 0)
                n += 1<<16;
        return n;
}

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 struct aoeif *
addif(struct aoetgt *t, struct net_device *nd)
{
        struct aoeif *p;

        p = getif(t, NULL);
        if (!p)
                return NULL;
        p->nd = nd;
        p->maxbcnt = DEFAULTBCNT;
        p->lost = 0;
        p->lostjumbo = 0;
        return p;
}

static void
ejectif(struct aoetgt *t, struct aoeif *ifp)
{
        struct aoeif *e;
        ulong n;

        e = t->ifs + NAOEIFS - 1;
        n = (e - ifp) * sizeof *ifp;
        memmove(ifp, ifp+1, n);
        e->nd = NULL;
}

static int
sthtith(struct aoedev *d)
{
        struct frame *f, *e, *nf;
        struct sk_buff *skb;
        struct aoetgt *ht = *d->htgt;

        f = ht->frames;
        e = f + ht->nframes;
        for (; f < e; f++) {
                if (f->tag == FREETAG)
                        continue;
                nf = freeframe(d);
                if (!nf)
                        return 0;
                skb = nf->skb;
                *nf = *f;
                f->skb = skb;
                f->tag = FREETAG;
                nf->waited = 0;
                ht->nout--;
                (*d->tgt)->nout++;
                resend(d, *d->tgt, nf);
        }
        /* he's clean, he's useless.  take away his interfaces */
        memset(ht->ifs, 0, sizeof ht->ifs);
        d->htgt = NULL;
        return 1;
}

static inline unsigned char
ata_scnt(unsigned char *packet) {
        struct aoe_hdr *h;
        struct aoe_atahdr *ah;

        h = (struct aoe_hdr *) packet;
        ah = (struct aoe_atahdr *) (h+1);
        return ah->scnt;
}

static void
rexmit_timer(ulong vp)
{
        struct aoedev *d;
        struct aoetgt *t, **tt, **te;
        struct aoeif *ifp;
        struct frame *f, *e;
        struct sk_buff *sl;
        register long timeout;
        ulong flags, n;

        d = (struct aoedev *) vp;
        sl = NULL;

        /* timeout is always ~150% of the moving average */
        timeout = d->rttavg;
        timeout += timeout >> 1;

        spin_lock_irqsave(&d->lock, flags);

        if (d->flags & DEVFL_TKILL) {
                spin_unlock_irqrestore(&d->lock, flags);
                return;
        }
        tt = d->targets;
        te = tt + NTARGETS;
        for (; tt < te && *tt; tt++) {
                t = *tt;
                f = t->frames;
                e = f + t->nframes;
                for (; f < e; f++) {
                        if (f->tag == FREETAG
                        || tsince(f->tag) < timeout)
                                continue;
                        n = f->waited += timeout;
                        n /= HZ;
                        if (n > aoe_deadsecs) {
                                /* waited too long.  device failure. */
                                aoedev_downdev(d);
                                break;
                        }

                        if (n > HELPWAIT /* see if another target can help */
                        && (tt != d->targets || d->targets[1]))
                                d->htgt = tt;

                        if (t->nout == t->maxout) {
                                if (t->maxout > 1)
                                        t->maxout--;
                                t->lastwadj = jiffies;
                        }

                        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;
                        }

                        if (ata_scnt(skb_mac_header(f->skb)) > DEFAULTBCNT / 512
                        && ifp && ++ifp->lostjumbo > (t->nframes << 1)
                        && ifp->maxbcnt != DEFAULTBCNT) {
                                printk(KERN_INFO
                                        "aoe: e%ld.%d: "
                                        "too many lost jumbo on "
                                        "%s:%012llx - "
                                        "falling back to %d frames.\n",
                                        d->aoemajor, d->aoeminor,
                                        ifp->nd->name, mac_addr(t->addr),
                                        DEFAULTBCNT);
                                ifp->maxbcnt = 0;
                        }
                        resend(d, t, f);
                }

                /* window check */
                if (t->nout == t->maxout
                && t->maxout < t->nframes
                && (jiffies - t->lastwadj)/HZ > 10) {
                        t->maxout++;
                        t->lastwadj = jiffies;
                }
        }

        if (d->sendq_hd) {
                n = d->rttavg <<= 1;
                if (n > MAXTIMER)
                        d->rttavg = MAXTIMER;
        }

        if (d->flags & DEVFL_KICKME || d->htgt) {
                d->flags &= ~DEVFL_KICKME;
                aoecmd_work(d);
        }

        sl = d->sendq_hd;
        d->sendq_hd = d->sendq_tl = NULL;

        d->timer.expires = jiffies + TIMERTICK;
        add_timer(&d->timer);

        spin_unlock_irqrestore(&d->lock, flags);

        aoenet_xmit(sl);
}

/* enters with d->lock held */
void
aoecmd_work(struct aoedev *d)
{
        struct buf *buf;
loop:
        if (d->htgt && !sthtith(d))
                return;
        if (d->inprocess == NULL) {
                if (list_empty(&d->bufq))
                        return;
                buf = container_of(d->bufq.next, struct buf, bufs);
                list_del(d->bufq.next);
                d->inprocess = buf;
        }
        if (aoecmd_ata_rw(d))
                goto loop;
}

/* 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) {
                struct block_device *bd;
                unsigned long flags;
                u64 ssize;

                ssize = d->gd->capacity;
                bd = bdget_disk(d->gd, 0);

                if (bd) {
                        mutex_lock(&bd->bd_inode->i_mutex);
                        i_size_write(bd->bd_inode, (loff_t)ssize<<9);
                        mutex_unlock(&bd->bd_inode->i_mutex);
                        bdput(bd);
                }
                spin_lock_irqsave(&d->lock, flags);
                d->flags |= DEVFL_UP;
                d->flags &= ~DEVFL_NEWSIZE;
                spin_unlock_irqrestore(&d->lock, flags);
        }
}

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]);
        }

        if (d->ssize != ssize)
                printk(KERN_INFO
                        "aoe: %012llx e%ld.%d v%04x has %llu sectors\n",
                        mac_addr(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->gd->capacity = ssize;
                d->flags |= DEVFL_NEWSIZE;
        } else
                d->flags |= DEVFL_GDALLOC;
        schedule_work(&d->work);
}

static void
calc_rttavg(struct aoedev *d, int rtt)
{
        register long n;

        n = rtt;
        if (n < 0) {
                n = -rtt;
                if (n < MINTIMER)
                        n = MINTIMER;
                else if (n > MAXTIMER)
                        n = MAXTIMER;
                d->mintimer += (n - d->mintimer) >> 1;
        } else if (n < d->mintimer)
                n = d->mintimer;
        else if (n > MAXTIMER)
                n = MAXTIMER;

        /* g == .25; cf. Congestion Avoidance and Control, Jacobson & Karels; 1988 */
        n -= d->rttavg;
        d->rttavg += n >> 2;
}

static struct aoetgt *
gettgt(struct aoedev *d, char *addr)
{
        struct aoetgt **t, **e;

        t = d->targets;
        e = t + NTARGETS;
        for (; t < e && *t; t++)
                if (memcmp((*t)->addr, addr, sizeof((*t)->addr)) == 0)
                        return *t;
        return NULL;
}

static inline void
diskstats(struct gendisk *disk, struct bio *bio, ulong duration, sector_t sector)
{
        unsigned long n_sect = bio->bi_size >> 9;
        const int rw = bio_data_dir(bio);
        struct hd_struct *part;

        part = get_part(disk, sector);
        all_stat_inc(disk, part, ios[rw], sector);
        all_stat_add(disk, part, ticks[rw], duration, sector);
        all_stat_add(disk, part, sectors[rw], n_sect, sector);
        all_stat_add(disk, part, io_ticks, duration, sector);
}

void
aoecmd_ata_rsp(struct sk_buff *skb)
{
        struct aoedev *d;
        struct aoe_hdr *hin, *hout;
        struct aoe_atahdr *ahin, *ahout;
        struct frame *f;
        struct buf *buf;
        struct sk_buff *sl;
        struct aoetgt *t;
        struct aoeif *ifp;
        register long n;
        ulong flags;
        char ebuf[128];
        u16 aoemajor;

        hin = (struct aoe_hdr *) skb_mac_header(skb);
        aoemajor = get_unaligned_be16(&hin->major);
        d = aoedev_by_aoeaddr(aoemajor, hin->minor);
        if (d == NULL) {
                snprintf(ebuf, sizeof ebuf, "aoecmd_ata_rsp: ata response "
                        "for unknown device %d.%d\n",
                         aoemajor, hin->minor);
                aoechr_error(ebuf);
                return;
        }

        spin_lock_irqsave(&d->lock, flags);

        n = get_unaligned_be32(&hin->tag);
        t = gettgt(d, hin->src);
        if (t == NULL) {
                printk(KERN_INFO "aoe: can't find target e%ld.%d:%012llx\n",
                        d->aoemajor, d->aoeminor, mac_addr(hin->src));
                spin_unlock_irqrestore(&d->lock, flags);
                return;
        }
        f = getframe(t, n);
        if (f == NULL) {
                calc_rttavg(d, -tsince(n));
                spin_unlock_irqrestore(&d->lock, flags);
                snprintf(ebuf, sizeof ebuf,
                        "%15s e%d.%d    tag=%08x@%08lx\n",
                        "unexpected rsp",
                        get_unaligned_be16(&hin->major),
                        hin->minor,
                        get_unaligned_be32(&hin->tag),
                        jiffies);
                aoechr_error(ebuf);
                return;
        }

        calc_rttavg(d, tsince(f->tag));

        ahin = (struct aoe_atahdr *) (hin+1);
        hout = (struct aoe_hdr *) skb_mac_header(f->skb);
        ahout = (struct aoe_atahdr *) (hout+1);
        buf = f->buf;

        if (ahin->cmdstat & 0xa9) {     /* these bits cleared on success */
                printk(KERN_ERR
                        "aoe: ata error cmd=%2.2Xh stat=%2.2Xh from e%ld.%d\n",
                        ahout->cmdstat, ahin->cmdstat,
                        d->aoemajor, d->aoeminor);
                if (buf)
                        buf->flags |= BUFFL_FAIL;
        } else {
                if (d->htgt && t == *d->htgt) /* I'll help myself, thank you. */
                        d->htgt = NULL;
                n = ahout->scnt << 9;
                switch (ahout->cmdstat) {
                case WIN_READ:
                case WIN_READ_EXT:
                        if (skb->len - sizeof *hin - sizeof *ahin < n) {
                                printk(KERN_ERR
                                        "aoe: %s.  skb->len=%d need=%ld\n",
                                        "runt data size in read", skb->len, n);
                                /* fail frame f?  just returning will rexmit. */
                                spin_unlock_irqrestore(&d->lock, flags);
                                return;
                        }
                        memcpy(f->bufaddr, ahin+1, n);
                case WIN_WRITE:
                case WIN_WRITE_EXT:
                        ifp = getif(t, skb->dev);
                        if (ifp) {
                                ifp->lost = 0;
                                if (n > DEFAULTBCNT)
                                        ifp->lostjumbo = 0;
                        }
                        if (f->bcnt -= n) {
                                f->lba += n >> 9;
                                f->bufaddr += n;
                                resend(d, t, f);
                                goto xmit;
                        }
                        break;
                case WIN_IDENTIFY:
                        if (skb->len - sizeof *hin - sizeof *ahin < 512) {
                                printk(KERN_INFO
                                        "aoe: runt data size in ataid.  skb->len=%d\n",
                                        skb->len);
                                spin_unlock_irqrestore(&d->lock, flags);
                                return;
                        }
                        ataid_complete(d, t, (char *) (ahin+1));
                        break;
                default:
                        printk(KERN_INFO
                                "aoe: unrecognized ata command %2.2Xh for %d.%d\n",
                                ahout->cmdstat,
                                get_unaligned_be16(&hin->major),
                                hin->minor);
                }
        }

        if (buf && --buf->nframesout == 0 && buf->resid == 0) {
                diskstats(d->gd, buf->bio, jiffies - buf->stime, buf->sector);
                n = (buf->flags & BUFFL_FAIL) ? -EIO : 0;
                bio_endio(buf->bio, n);
                mempool_free(buf, d->bufpool);
        }

        f->buf = NULL;
        f->tag = FREETAG;
        t->nout--;

        aoecmd_work(d);
xmit:
        sl = d->sendq_hd;
        d->sendq_hd = d->sendq_tl = NULL;

        spin_unlock_irqrestore(&d->lock, flags);
        aoenet_xmit(sl);
}

void
aoecmd_cfg(ushort aoemajor, unsigned char aoeminor)
{
        struct sk_buff *sl;

        sl = aoecmd_cfg_pkts(aoemajor, aoeminor, NULL);

        aoenet_xmit(sl);
}
 
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 = freeframe(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);
        t->nout++;
        f->waited = 0;

        /* set up ata header */
        ah->scnt = 1;
        ah->cmdstat = WIN_IDENTIFY;
        ah->lba3 = 0xa0;

        skb->dev = t->ifp->nd;

        d->rttavg = MAXTIMER;
        d->timer.function = rexmit_timer;

        return skb_clone(skb, GFP_ATOMIC);
}
 
static struct aoetgt *
addtgt(struct aoedev *d, char *addr, ulong nframes)
{
        struct aoetgt *t, **tt, **te;
        struct frame *f, *e;

        tt = d->targets;
        te = tt + NTARGETS;
        for (; tt < te && *tt; tt++)
                ;

        if (tt == te) {
                printk(KERN_INFO
                        "aoe: device addtgt failure; too many targets\n");
                return NULL;
        }
        t = kcalloc(1, sizeof *t, GFP_ATOMIC);
        f = kcalloc(nframes, sizeof *f, GFP_ATOMIC);
        if (!t || !f) {
                kfree(f);
                kfree(t);
                printk(KERN_INFO "aoe: cannot allocate memory to add target\n");
                return NULL;
        }

        t->nframes = nframes;
        t->frames = f;
        e = f + nframes;
        for (; f < e; f++)
                f->tag = FREETAG;
        memcpy(t->addr, addr, sizeof t->addr);
        t->ifp = t->ifs;
        t->maxout = t->nframes;
        return *tt = t;
}

void
aoecmd_cfg_rsp(struct sk_buff *skb)
{
        struct aoedev *d;
        struct aoe_hdr *h;
        struct aoe_cfghdr *ch;
        struct aoetgt *t;
        struct aoeif *ifp;
        ulong flags, sysminor, aoemajor;
        struct sk_buff *sl;
        u16 n;

        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 = be16_to_cpu(get_unaligned(&h->major));
        if (aoemajor == 0xfff) {
                printk(KERN_ERR "aoe: Warning: shelf address is all ones.  "
                        "Check shelf dip switches.\n");
                return;
        }

        sysminor = SYSMINOR(aoemajor, h->minor);
        if (sysminor * AOE_PARTITIONS + AOE_PARTITIONS > MINORMASK) {
                printk(KERN_INFO "aoe: e%ld.%d: minor number too large\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_sysminor_m(sysminor);
        if (d == NULL) {
                printk(KERN_INFO "aoe: device sysminor_m failure\n");
                return;
        }

        spin_lock_irqsave(&d->lock, flags);

        t = gettgt(d, h->src);
        if (!t) {
                t = addtgt(d, h->src, n);
                if (!t) {
                        spin_unlock_irqrestore(&d->lock, flags);
                        return;
                }
        }
        ifp = getif(t, skb->dev);
        if (!ifp) {
                ifp = addif(t, skb->dev);
                if (!ifp) {
                        printk(KERN_INFO
                                "aoe: device addif failure; "
                                "too many interfaces?\n");
                        spin_unlock_irqrestore(&d->lock, flags);
                        return;
                }
        }
        if (ifp->maxbcnt) {
                n = ifp->nd->mtu;
                n -= sizeof (struct aoe_hdr) + sizeof (struct aoe_atahdr);
                n /= 512;
                if (n > ch->scnt)
                        n = ch->scnt;
                n = n ? n * 512 : DEFAULTBCNT;
                if (n != ifp->maxbcnt) {
                        printk(KERN_INFO
                                "aoe: e%ld.%d: setting %d%s%s:%012llx\n",
                                d->aoemajor, d->aoeminor, n,
                                " byte data frames on ", ifp->nd->name,
                                mac_addr(t->addr));
                        ifp->maxbcnt = n;
                }
        }

        /* don't change users' perspective */
        if (d->nopen) {
                spin_unlock_irqrestore(&d->lock, flags);
                return;
        }
        d->fw_ver = be16_to_cpu(ch->fwver);

        sl = aoecmd_ata_id(d);

        spin_unlock_irqrestore(&d->lock, flags);

        aoenet_xmit(sl);
}

void
aoecmd_cleanslate(struct aoedev *d)
{
        struct aoetgt **t, **te;
        struct aoeif *p, *e;

        d->mintimer = MINTIMER;

        t = d->targets;
        te = t + NTARGETS;
        for (; t < te && *t; t++) {
                (*t)->maxout = (*t)->nframes;
                p = (*t)->ifs;
                e = p + NAOEIFS;
                for (; p < e; p++) {
                        p->lostjumbo = 0;
                        p->lost = 0;
                        p->maxbcnt = DEFAULTBCNT;
                }
        }
}