drivers/block/aoe/aoecmd.c

   1 /* Copyright (c) 2012 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
  24 static void ktcomplete(struct frame *, struct sk_buff *);
  25 static int count_targets(struct aoedev *d, int *untainted);
  26
  27 static struct buf *nextbuf(struct aoedev *);
  28
  29 static int aoe_deadsecs = 60 * 3;
  30 module_param(aoe_deadsecs, int, 0644);
  31 MODULE_PARM_DESC(aoe_deadsecs, "After aoe_deadsecs seconds, give up and fail dev.");
  32
  33 static int aoe_maxout = 64;
  34 module_param(aoe_maxout, int, 0644);
  35 MODULE_PARM_DESC(aoe_maxout,
  36         "Only aoe_maxout outstanding packets for every MAC on eX.Y.");
  37
  38 static wait_queue_head_t ktiowq;
  39 static struct ktstate kts;
  40
  41 /* io completion queue */
  42 static struct {
  43         struct list_head head;
  44         spinlock_t lock;
  45 } iocq;
  46
  47 static struct page *empty_page;
  48
  49 static struct sk_buff *
  50 new_skb(ulong len)
  51 {
  52         struct sk_buff *skb;
  53
  54         skb = alloc_skb(len + MAX_HEADER, GFP_ATOMIC);
  55         if (skb) {
  56                 skb_reserve(skb, MAX_HEADER);
  57                 skb_reset_mac_header(skb);
  58                 skb_reset_network_header(skb);
  59                 skb->protocol = __constant_htons(ETH_P_AOE);
  60                 skb_checksum_none_assert(skb);
  61         }
  62         return skb;
  63 }
  64
  65 static struct frame *
  66 getframe_deferred(struct aoedev *d, u32 tag)
  67 {
  68         struct list_head *head, *pos, *nx;
  69         struct frame *f;
  70
  71         head = &d->rexmitq;
  72         list_for_each_safe(pos, nx, head) {
  73                 f = list_entry(pos, struct frame, head);
  74                 if (f->tag == tag) {
  75                         list_del(pos);
  76                         return f;
  77                 }
  78         }
  79         return NULL;
  80 }
  81
  82 static struct frame *
  83 getframe(struct aoedev *d, u32 tag)
  84 {
  85         struct frame *f;
  86         struct list_head *head, *pos, *nx;
  87         u32 n;
  88
  89         n = tag % NFACTIVE;
  90         head = &d->factive[n];
  91         list_for_each_safe(pos, nx, head) {
  92                 f = list_entry(pos, struct frame, head);
  93                 if (f->tag == tag) {
  94                         list_del(pos);
  95                         return f;
  96                 }
  97         }
  98         return NULL;
  99 }
 100
 101 /*
 102  * Leave the top bit clear so we have tagspace for userland.
 103  * The bottom 16 bits are the xmit tick for rexmit/rttavg processing.
 104  * This driver reserves tag -1 to mean "unused frame."
 105  */
 106 static int
 107 newtag(struct aoedev *d)
 108 {
 109         register ulong n;
 110
 111         n = jiffies & 0xffff;
 112         return n |= (++d->lasttag & 0x7fff) << 16;
 113 }
 114
 115 static u32
 116 aoehdr_atainit(struct aoedev *d, struct aoetgt *t, struct aoe_hdr *h)
 117 {
 118         u32 host_tag = newtag(d);
 119
 120         memcpy(h->src, t->ifp->nd->dev_addr, sizeof h->src);
 121         memcpy(h->dst, t->addr, sizeof h->dst);
 122         h->type = __constant_cpu_to_be16(ETH_P_AOE);
 123         h->verfl = AOE_HVER;
 124         h->major = cpu_to_be16(d->aoemajor);
 125         h->minor = d->aoeminor;
 126         h->cmd = AOECMD_ATA;
 127         h->tag = cpu_to_be32(host_tag);
 128
 129         return host_tag;
 130 }
 131
 132 static inline void
 133 put_lba(struct aoe_atahdr *ah, sector_t lba)
 134 {
 135         ah->lba0 = lba;
 136         ah->lba1 = lba >>= 8;
 137         ah->lba2 = lba >>= 8;
 138         ah->lba3 = lba >>= 8;
 139         ah->lba4 = lba >>= 8;
 140         ah->lba5 = lba >>= 8;
 141 }
 142
 143 static struct aoeif *
 144 ifrotate(struct aoetgt *t)
 145 {
 146         struct aoeif *ifp;
 147
 148         ifp = t->ifp;
 149         ifp++;
 150         if (ifp >= &t->ifs[NAOEIFS] || ifp->nd == NULL)
 151                 ifp = t->ifs;
 152         if (ifp->nd == NULL)
 153                 return NULL;
 154         return t->ifp = ifp;
 155 }
 156
 157 static void
 158 skb_pool_put(struct aoedev *d, struct sk_buff *skb)
 159 {
 160         __skb_queue_tail(&d->skbpool, skb);
 161 }
 162
 163 static struct sk_buff *
 164 skb_pool_get(struct aoedev *d)
 165 {
 166         struct sk_buff *skb = skb_peek(&d->skbpool);
 167
 168         if (skb && atomic_read(&skb_shinfo(skb)->dataref) == 1) {
 169                 __skb_unlink(skb, &d->skbpool);
 170                 return skb;
 171         }
 172         if (skb_queue_len(&d->skbpool) < NSKBPOOLMAX &&
 173             (skb = new_skb(ETH_ZLEN)))
 174                 return skb;
 175
 176         return NULL;
 177 }
 178
 179 void
 180 aoe_freetframe(struct frame *f)
 181 {
 182         struct aoetgt *t;
 183
 184         t = f->t;
 185         f->buf = NULL;
 186         f->lba = 0;
 187         f->bv = NULL;
 188         f->r_skb = NULL;
 189         f->flags = 0;
 190         list_add(&f->head, &t->ffree);
 191 }
 192
 193 static struct frame *
 194 newtframe(struct aoedev *d, struct aoetgt *t)
 195 {
 196         struct frame *f;
 197         struct sk_buff *skb;
 198         struct list_head *pos;
 199
 200         if (list_empty(&t->ffree)) {
 201                 if (t->falloc >= NSKBPOOLMAX*2)
 202                         return NULL;
 203                 f = kcalloc(1, sizeof(*f), GFP_ATOMIC);
 204                 if (f == NULL)
 205                         return NULL;
 206                 t->falloc++;
 207                 f->t = t;
 208         } else {
 209                 pos = t->ffree.next;
 210                 list_del(pos);
 211                 f = list_entry(pos, struct frame, head);
 212         }
 213
 214         skb = f->skb;
 215         if (skb == NULL) {
 216                 f->skb = skb = new_skb(ETH_ZLEN);
 217                 if (!skb) {
 218 bail:                   aoe_freetframe(f);
 219                         return NULL;
 220                 }
 221         }
 222
 223         if (atomic_read(&skb_shinfo(skb)->dataref) != 1) {
 224                 skb = skb_pool_get(d);
 225                 if (skb == NULL)
 226                         goto bail;
 227                 skb_pool_put(d, f->skb);
 228                 f->skb = skb;
 229         }
 230
 231         skb->truesize -= skb->data_len;
 232         skb_shinfo(skb)->nr_frags = skb->data_len = 0;
 233         skb_trim(skb, 0);
 234         return f;
 235 }
 236
 237 static struct frame *
 238 newframe(struct aoedev *d)
 239 {
 240         struct frame *f;
 241         struct aoetgt *t, **tt;
 242         int totout = 0;
 243         int use_tainted;
 244         int has_untainted;
 245
 246         if (!d->targets || !d->targets[0]) {
 247                 printk(KERN_ERR "aoe: NULL TARGETS!\n");
 248                 return NULL;
 249         }
 250         tt = d->tgt;    /* last used target */
 251         for (use_tainted = 0, has_untainted = 0;;) {
 252                 tt++;
 253                 if (tt >= &d->targets[d->ntargets] || !*tt)
 254                         tt = d->targets;
 255                 t = *tt;
 256                 if (!t->taint) {
 257                         has_untainted = 1;
 258                         totout += t->nout;
 259                 }
 260                 if (t->nout < t->maxout
 261                 && (use_tainted || !t->taint)
 262                 && t->ifp->nd) {
 263                         f = newtframe(d, t);
 264                         if (f) {
 265                                 ifrotate(t);
 266                                 d->tgt = tt;
 267                                 return f;
 268                         }
 269                 }
 270                 if (tt == d->tgt) {     /* we've looped and found nada */
 271                         if (!use_tainted && !has_untainted)
 272                                 use_tainted = 1;
 273                         else
 274                                 break;
 275                 }
 276         }
 277         if (totout == 0) {
 278                 d->kicked++;
 279                 d->flags |= DEVFL_KICKME;
 280         }
 281         return NULL;
 282 }
 283
 284 static void
 285 skb_fillup(struct sk_buff *skb, struct bio_vec *bv, ulong off, ulong cnt)
 286 {
 287         int frag = 0;
 288         ulong fcnt;
 289 loop:
 290         fcnt = bv->bv_len - (off - bv->bv_offset);
 291         if (fcnt > cnt)
 292                 fcnt = cnt;
 293         skb_fill_page_desc(skb, frag++, bv->bv_page, off, fcnt);
 294         cnt -= fcnt;
 295         if (cnt <= 0)
 296                 return;
 297         bv++;
 298         off = bv->bv_offset;
 299         goto loop;
 300 }
 301
 302 static void
 303 fhash(struct frame *f)
 304 {
 305         struct aoedev *d = f->t->d;
 306         u32 n;
 307
 308         n = f->tag % NFACTIVE;
 309         list_add_tail(&f->head, &d->factive[n]);
 310 }
 311
 312 static void
 313 ata_rw_frameinit(struct frame *f)
 314 {
 315         struct aoetgt *t;
 316         struct aoe_hdr *h;
 317         struct aoe_atahdr *ah;
 318         struct sk_buff *skb;
 319         char writebit, extbit;
 320
 321         skb = f->skb;
 322         h = (struct aoe_hdr *) skb_mac_header(skb);
 323         ah = (struct aoe_atahdr *) (h + 1);
 324         skb_put(skb, sizeof(*h) + sizeof(*ah));
 325         memset(h, 0, skb->len);
 326
 327         writebit = 0x10;
 328         extbit = 0x4;
 329
 330         t = f->t;
 331         f->tag = aoehdr_atainit(t->d, t, h);
 332         fhash(f);
 333         t->nout++;
 334         f->waited = 0;
 335         f->waited_total = 0;
 336         if (f->buf)
 337                 f->lba = f->buf->sector;
 338
 339         /* set up ata header */
 340         ah->scnt = f->bcnt >> 9;
 341         put_lba(ah, f->lba);
 342         if (t->d->flags & DEVFL_EXT) {
 343                 ah->aflags |= AOEAFL_EXT;
 344         } else {
 345                 extbit = 0;
 346                 ah->lba3 &= 0x0f;
 347                 ah->lba3 |= 0xe0;       /* LBA bit + obsolete 0xa0 */
 348         }
 349         if (f->buf && bio_data_dir(f->buf->bio) == WRITE) {
 350                 skb_fillup(skb, f->bv, f->bv_off, f->bcnt);
 351                 ah->aflags |= AOEAFL_WRITE;
 352                 skb->len += f->bcnt;
 353                 skb->data_len = f->bcnt;
 354                 skb->truesize += f->bcnt;
 355                 t->wpkts++;
 356         } else {
 357                 t->rpkts++;
 358                 writebit = 0;
 359         }
 360
 361         ah->cmdstat = ATA_CMD_PIO_READ | writebit | extbit;
 362         skb->dev = t->ifp->nd;
 363 }
 364
 365 static int
 366 aoecmd_ata_rw(struct aoedev *d)
 367 {
 368         struct frame *f;
 369         struct buf *buf;
 370         struct aoetgt *t;
 371         struct sk_buff *skb;
 372         struct sk_buff_head queue;
 373         ulong bcnt, fbcnt;
 374
 375         buf = nextbuf(d);
 376         if (buf == NULL)
 377                 return 0;
 378         f = newframe(d);
 379         if (f == NULL)
 380                 return 0;
 381         t = *d->tgt;
 382         bcnt = d->maxbcnt;
 383         if (bcnt == 0)
 384                 bcnt = DEFAULTBCNT;
 385         if (bcnt > buf->resid)
 386                 bcnt = buf->resid;
 387         fbcnt = bcnt;
 388         f->bv = buf->bv;
 389         f->bv_off = f->bv->bv_offset + (f->bv->bv_len - buf->bv_resid);
 390         do {
 391                 if (fbcnt < buf->bv_resid) {
 392                         buf->bv_resid -= fbcnt;
 393                         buf->resid -= fbcnt;
 394                         break;
 395                 }
 396                 fbcnt -= buf->bv_resid;
 397                 buf->resid -= buf->bv_resid;
 398                 if (buf->resid == 0) {
 399                         d->ip.buf = NULL;
 400                         break;
 401                 }
 402                 buf->bv++;
 403                 buf->bv_resid = buf->bv->bv_len;
 404                 WARN_ON(buf->bv_resid == 0);
 405         } while (fbcnt);
 406
 407         /* initialize the headers & frame */
 408         f->buf = buf;
 409         f->bcnt = bcnt;
 410         ata_rw_frameinit(f);
 411
 412         /* mark all tracking fields and load out */
 413         buf->nframesout += 1;
 414         buf->sector += bcnt >> 9;
 415
 416         skb = skb_clone(f->skb, GFP_ATOMIC);
 417         if (skb) {
 418                 do_gettimeofday(&f->sent);
 419                 f->sent_jiffs = (u32) jiffies;
 420                 __skb_queue_head_init(&queue);
 421                 __skb_queue_tail(&queue, skb);
 422                 aoenet_xmit(&queue);
 423         }
 424         return 1;
 425 }
 426
 427 /* some callers cannot sleep, and they can call this function,
 428  * transmitting the packets later, when interrupts are on
 429  */
 430 static void
 431 aoecmd_cfg_pkts(ushort aoemajor, unsigned char aoeminor, struct sk_buff_head *queue)
 432 {
 433         struct aoe_hdr *h;
 434         struct aoe_cfghdr *ch;
 435         struct sk_buff *skb;
 436         struct net_device *ifp;
 437
 438         rcu_read_lock();
 439         for_each_netdev_rcu(&init_net, ifp) {
 440                 dev_hold(ifp);
 441                 if (!is_aoe_netif(ifp))
 442                         goto cont;
 443
 444                 skb = new_skb(sizeof *h + sizeof *ch);
 445                 if (skb == NULL) {
 446                         printk(KERN_INFO "aoe: skb alloc failure\n");
 447                         goto cont;
 448                 }
 449                 skb_put(skb, sizeof *h + sizeof *ch);
 450                 skb->dev = ifp;
 451                 __skb_queue_tail(queue, skb);
 452                 h = (struct aoe_hdr *) skb_mac_header(skb);
 453                 memset(h, 0, sizeof *h + sizeof *ch);
 454
 455                 memset(h->dst, 0xff, sizeof h->dst);
 456                 memcpy(h->src, ifp->dev_addr, sizeof h->src);
 457                 h->type = __constant_cpu_to_be16(ETH_P_AOE);
 458                 h->verfl = AOE_HVER;
 459                 h->major = cpu_to_be16(aoemajor);
 460                 h->minor = aoeminor;
 461                 h->cmd = AOECMD_CFG;
 462
 463 cont:
 464                 dev_put(ifp);
 465         }
 466         rcu_read_unlock();
 467 }
 468
 469 static void
 470 resend(struct aoedev *d, struct frame *f)
 471 {
 472         struct sk_buff *skb;
 473         struct sk_buff_head queue;
 474         struct aoe_hdr *h;
 475         struct aoe_atahdr *ah;
 476         struct aoetgt *t;
 477         char buf[128];
 478         u32 n;
 479
 480         t = f->t;
 481         n = newtag(d);
 482         skb = f->skb;
 483         if (ifrotate(t) == NULL) {
 484                 /* probably can't happen, but set it up to fail anyway */
 485                 pr_info("aoe: resend: no interfaces to rotate to.\n");
 486                 ktcomplete(f, NULL);
 487                 return;
 488         }
 489         h = (struct aoe_hdr *) skb_mac_header(skb);
 490         ah = (struct aoe_atahdr *) (h+1);
 491
 492         if (!(f->flags & FFL_PROBE)) {
 493                 snprintf(buf, sizeof(buf),
 494                         "%15s e%ld.%d oldtag=%08x@%08lx newtag=%08x s=%pm d=%pm nout=%d\n",
 495                         "retransmit", d->aoemajor, d->aoeminor,
 496                         f->tag, jiffies, n,
 497                         h->src, h->dst, t->nout);
 498                 aoechr_error(buf);
 499         }
 500
 501         f->tag = n;
 502         fhash(f);
 503         h->tag = cpu_to_be32(n);
 504         memcpy(h->dst, t->addr, sizeof h->dst);
 505         memcpy(h->src, t->ifp->nd->dev_addr, sizeof h->src);
 506
 507         skb->dev = t->ifp->nd;
 508         skb = skb_clone(skb, GFP_ATOMIC);
 509         if (skb == NULL)
 510                 return;
 511         do_gettimeofday(&f->sent);
 512         f->sent_jiffs = (u32) jiffies;
 513         __skb_queue_head_init(&queue);
 514         __skb_queue_tail(&queue, skb);
 515         aoenet_xmit(&queue);
 516 }
 517
 518 static int
 519 tsince_hr(struct frame *f)
 520 {
 521         struct timeval now;
 522         int n;
 523
 524         do_gettimeofday(&now);
 525         n = now.tv_usec - f->sent.tv_usec;
 526         n += (now.tv_sec - f->sent.tv_sec) * USEC_PER_SEC;
 527
 528         if (n < 0)
 529                 n = -n;
 530
 531         /* For relatively long periods, use jiffies to avoid
 532          * discrepancies caused by updates to the system time.
 533          *
 534          * On system with HZ of 1000, 32-bits is over 49 days
 535          * worth of jiffies, or over 71 minutes worth of usecs.
 536          *
 537          * Jiffies overflow is handled by subtraction of unsigned ints:
 538          * (gdb) print (unsigned) 2 - (unsigned) 0xfffffffe
 539          * $3 = 4
 540          * (gdb)
 541          */
 542         if (n > USEC_PER_SEC / 4) {
 543                 n = ((u32) jiffies) - f->sent_jiffs;
 544                 n *= USEC_PER_SEC / HZ;
 545         }
 546
 547         return n;
 548 }
 549
 550 static int
 551 tsince(u32 tag)
 552 {
 553         int n;
 554
 555         n = jiffies & 0xffff;
 556         n -= tag & 0xffff;
 557         if (n < 0)
 558                 n += 1<<16;
 559         return jiffies_to_usecs(n + 1);
 560 }
 561
 562 static struct aoeif *
 563 getif(struct aoetgt *t, struct net_device *nd)
 564 {
 565         struct aoeif *p, *e;
 566
 567         p = t->ifs;
 568         e = p + NAOEIFS;
 569         for (; p < e; p++)
 570                 if (p->nd == nd)
 571                         return p;
 572         return NULL;
 573 }
 574
 575 static void
 576 ejectif(struct aoetgt *t, struct aoeif *ifp)
 577 {
 578         struct aoeif *e;
 579         struct net_device *nd;
 580         ulong n;
 581
 582         nd = ifp->nd;
 583         e = t->ifs + NAOEIFS - 1;
 584         n = (e - ifp) * sizeof *ifp;
 585         memmove(ifp, ifp+1, n);
 586         e->nd = NULL;
 587         dev_put(nd);
 588 }
 589
 590 static struct frame *
 591 reassign_frame(struct frame *f)
 592 {
 593         struct frame *nf;
 594         struct sk_buff *skb;
 595
 596         nf = newframe(f->t->d);
 597         if (!nf)
 598                 return NULL;
 599         if (nf->t == f->t) {
 600                 aoe_freetframe(nf);
 601                 return NULL;
 602         }
 603
 604         skb = nf->skb;
 605         nf->skb = f->skb;
 606         nf->buf = f->buf;
 607         nf->bcnt = f->bcnt;
 608         nf->lba = f->lba;
 609         nf->bv = f->bv;
 610         nf->bv_off = f->bv_off;
 611         nf->waited = 0;
 612         nf->waited_total = f->waited_total;
 613         nf->sent = f->sent;
 614         nf->sent_jiffs = f->sent_jiffs;
 615         f->skb = skb;
 616
 617         return nf;
 618 }
 619
 620 static void
 621 probe(struct aoetgt *t)
 622 {
 623         struct aoedev *d;
 624         struct frame *f;
 625         struct sk_buff *skb;
 626         struct sk_buff_head queue;
 627         size_t n, m;
 628         int frag;
 629
 630         d = t->d;
 631         f = newtframe(d, t);
 632         if (!f) {
 633                 pr_err("%s %pm for e%ld.%d: %s\n",
 634                         "aoe: cannot probe remote address",
 635                         t->addr,
 636                         (long) d->aoemajor, d->aoeminor,
 637                         "no frame available");
 638                 return;
 639         }
 640         f->flags |= FFL_PROBE;
 641         ifrotate(t);
 642         f->bcnt = t->d->maxbcnt ? t->d->maxbcnt : DEFAULTBCNT;
 643         ata_rw_frameinit(f);
 644         skb = f->skb;
 645         for (frag = 0, n = f->bcnt; n > 0; ++frag, n -= m) {
 646                 if (n < PAGE_SIZE)
 647                         m = n;
 648                 else
 649                         m = PAGE_SIZE;
 650                 skb_fill_page_desc(skb, frag, empty_page, 0, m);
 651         }
 652         skb->len += f->bcnt;
 653         skb->data_len = f->bcnt;
 654         skb->truesize += f->bcnt;
 655
 656         skb = skb_clone(f->skb, GFP_ATOMIC);
 657         if (skb) {
 658                 do_gettimeofday(&f->sent);
 659                 f->sent_jiffs = (u32) jiffies;
 660                 __skb_queue_head_init(&queue);
 661                 __skb_queue_tail(&queue, skb);
 662                 aoenet_xmit(&queue);
 663         }
 664 }
 665
 666 static long
 667 rto(struct aoedev *d)
 668 {
 669         long t;
 670
 671         t = 2 * d->rttavg >> RTTSCALE;
 672         t += 8 * d->rttdev >> RTTDSCALE;
 673         if (t == 0)
 674                 t = 1;
 675
 676         return t;
 677 }
 678
 679 static void
 680 rexmit_deferred(struct aoedev *d)
 681 {
 682         struct aoetgt *t;
 683         struct frame *f;
 684         struct frame *nf;
 685         struct list_head *pos, *nx, *head;
 686         int since;
 687         int untainted;
 688
 689         count_targets(d, &untainted);
 690
 691         head = &d->rexmitq;
 692         list_for_each_safe(pos, nx, head) {
 693                 f = list_entry(pos, struct frame, head);
 694                 t = f->t;
 695                 if (t->taint) {
 696                         if (!(f->flags & FFL_PROBE)) {
 697                                 nf = reassign_frame(f);
 698                                 if (nf) {
 699                                         if (t->nout_probes == 0
 700                                         && untainted > 0) {
 701                                                 probe(t);
 702                                                 t->nout_probes++;
 703                                         }
 704                                         list_replace(&f->head, &nf->head);
 705                                         pos = &nf->head;
 706                                         aoe_freetframe(f);
 707                                         f = nf;
 708                                         t = f->t;
 709                                 }
 710                         } else if (untainted < 1) {
 711                                 /* don't probe w/o other untainted aoetgts */
 712                                 goto stop_probe;
 713                         } else if (tsince_hr(f) < t->taint * rto(d)) {
 714                                 /* reprobe slowly when taint is high */
 715                                 continue;
 716                         }
 717                 } else if (f->flags & FFL_PROBE) {
 718 stop_probe:             /* don't probe untainted aoetgts */
 719                         list_del(pos);
 720                         aoe_freetframe(f);
 721                         /* leaving d->kicked, because this is routine */
 722                         f->t->d->flags |= DEVFL_KICKME;
 723                         continue;
 724                 }
 725                 if (t->nout >= t->maxout)
 726                         continue;
 727                 list_del(pos);
 728                 t->nout++;
 729                 if (f->flags & FFL_PROBE)
 730                         t->nout_probes++;
 731                 since = tsince_hr(f);
 732                 f->waited += since;
 733                 f->waited_total += since;
 734                 resend(d, f);
 735         }
 736 }
 737
 738 /* An aoetgt accumulates demerits quickly, and successful
 739  * probing redeems the aoetgt slowly.
 740  */
 741 static void
 742 scorn(struct aoetgt *t)
 743 {
 744         int n;
 745
 746         n = t->taint++;
 747         t->taint += t->taint * 2;
 748         if (n > t->taint)
 749                 t->taint = n;
 750         if (t->taint > MAX_TAINT)
 751                 t->taint = MAX_TAINT;
 752 }
 753
 754 static int
 755 count_targets(struct aoedev *d, int *untainted)
 756 {
 757         int i, good;
 758
 759         for (i = good = 0; i < d->ntargets && d->targets[i]; ++i)
 760                 if (d->targets[i]->taint == 0)
 761                         good++;
 762
 763         if (untainted)
 764                 *untainted = good;
 765         return i;
 766 }
 767
 768 static void
 769 rexmit_timer(ulong vp)
 770 {
 771         struct aoedev *d;
 772         struct aoetgt *t;
 773         struct aoeif *ifp;
 774         struct frame *f;
 775         struct list_head *head, *pos, *nx;
 776         LIST_HEAD(flist);
 777         register long timeout;
 778         ulong flags, n;
 779         int i;
 780         int utgts;      /* number of aoetgt descriptors (not slots) */
 781         int since;
 782
 783         d = (struct aoedev *) vp;
 784
 785         spin_lock_irqsave(&d->lock, flags);
 786
 787         /* timeout based on observed timings and variations */
 788         timeout = rto(d);
 789
 790         utgts = count_targets(d, NULL);
 791
 792         if (d->flags & DEVFL_TKILL) {
 793                 spin_unlock_irqrestore(&d->lock, flags);
 794                 return;
 795         }
 796
 797         /* collect all frames to rexmit into flist */
 798         for (i = 0; i < NFACTIVE; i++) {
 799                 head = &d->factive[i];
 800                 list_for_each_safe(pos, nx, head) {
 801                         f = list_entry(pos, struct frame, head);
 802                         if (tsince_hr(f) < timeout)
 803                                 break;  /* end of expired frames */
 804                         /* move to flist for later processing */
 805                         list_move_tail(pos, &flist);
 806                 }
 807         }
 808
 809         /* process expired frames */
 810         while (!list_empty(&flist)) {
 811                 pos = flist.next;
 812                 f = list_entry(pos, struct frame, head);
 813                 since = tsince_hr(f);
 814                 n = f->waited_total + since;
 815                 n /= USEC_PER_SEC;
 816                 if (aoe_deadsecs
 817                 && n > aoe_deadsecs
 818                 && !(f->flags & FFL_PROBE)) {
 819                         /* Waited too long.  Device failure.
 820                          * Hang all frames on first hash bucket for downdev
 821                          * to clean up.
 822                          */
 823                         list_splice(&flist, &d->factive[0]);
 824                         aoedev_downdev(d);
 825                         goto out;
 826                 }
 827
 828                 t = f->t;
 829                 n = f->waited + since;
 830                 n /= USEC_PER_SEC;
 831                 if (aoe_deadsecs && utgts > 0
 832                 && (n > aoe_deadsecs / utgts || n > HARD_SCORN_SECS))
 833                         scorn(t); /* avoid this target */
 834
 835                 if (t->maxout != 1) {
 836                         t->ssthresh = t->maxout / 2;
 837                         t->maxout = 1;
 838                 }
 839
 840                 if (f->flags & FFL_PROBE) {
 841                         t->nout_probes--;
 842                 } else {
 843                         ifp = getif(t, f->skb->dev);
 844                         if (ifp && ++ifp->lost > (t->nframes << 1)
 845                         && (ifp != t->ifs || t->ifs[1].nd)) {
 846                                 ejectif(t, ifp);
 847                                 ifp = NULL;
 848                         }
 849                 }
 850                 list_move_tail(pos, &d->rexmitq);
 851                 t->nout--;
 852         }
 853         rexmit_deferred(d);
 854
 855 out:
 856         if ((d->flags & DEVFL_KICKME) && d->blkq) {
 857                 d->flags &= ~DEVFL_KICKME;
 858                 d->blkq->request_fn(d->blkq);
 859         }
 860
 861         d->timer.expires = jiffies + TIMERTICK;
 862         add_timer(&d->timer);
 863
 864         spin_unlock_irqrestore(&d->lock, flags);
 865 }
 866
 867 static unsigned long
 868 rqbiocnt(struct request *r)
 869 {
 870         struct bio *bio;
 871         unsigned long n = 0;
 872
 873         __rq_for_each_bio(bio, r)
 874                 n++;
 875         return n;
 876 }
 877
 878 /* This can be removed if we are certain that no users of the block
 879  * layer will ever use zero-count pages in bios.  Otherwise we have to
 880  * protect against the put_page sometimes done by the network layer.
 881  *
 882  * See http://oss.sgi.com/archives/xfs/2007-01/msg00594.html for
 883  * discussion.
 884  *
 885  * We cannot use get_page in the workaround, because it insists on a
 886  * positive page count as a precondition.  So we use _count directly.
 887  */
 888 static void
 889 bio_pageinc(struct bio *bio)
 890 {
 891         struct bio_vec *bv;
 892         struct page *page;
 893         int i;
 894
 895         bio_for_each_segment(bv, bio, i) {
 896                 page = bv->bv_page;
 897                 /* Non-zero page count for non-head members of
 898                  * compound pages is no longer allowed by the kernel,
 899                  * but this has never been seen here.
 900                  */
 901                 if (unlikely(PageCompound(page)))
 902                         if (compound_trans_head(page) != page) {
 903                                 pr_crit("page tail used for block I/O\n");
 904                                 BUG();
 905                         }
 906                 atomic_inc(&page->_count);
 907         }
 908 }
 909
 910 static void
 911 bio_pagedec(struct bio *bio)
 912 {
 913         struct bio_vec *bv;
 914         int i;
 915
 916         bio_for_each_segment(bv, bio, i)
 917                 atomic_dec(&bv->bv_page->_count);
 918 }
 919
 920 static void
 921 bufinit(struct buf *buf, struct request *rq, struct bio *bio)
 922 {
 923         struct bio_vec *bv;
 924
 925         memset(buf, 0, sizeof(*buf));
 926         buf->rq = rq;
 927         buf->bio = bio;
 928         buf->resid = bio->bi_size;
 929         buf->sector = bio->bi_sector;
 930         bio_pageinc(bio);
 931         buf->bv = bv = bio_iovec(bio);
 932         buf->bv_resid = bv->bv_len;
 933         WARN_ON(buf->bv_resid == 0);
 934 }
 935
 936 static struct buf *
 937 nextbuf(struct aoedev *d)
 938 {
 939         struct request *rq;
 940         struct request_queue *q;
 941         struct buf *buf;
 942         struct bio *bio;
 943
 944         q = d->blkq;
 945         if (q == NULL)
 946                 return NULL;    /* initializing */
 947         if (d->ip.buf)
 948                 return d->ip.buf;
 949         rq = d->ip.rq;
 950         if (rq == NULL) {
 951                 rq = blk_peek_request(q);
 952                 if (rq == NULL)
 953                         return NULL;
 954                 blk_start_request(rq);
 955                 d->ip.rq = rq;
 956                 d->ip.nxbio = rq->bio;
 957                 rq->special = (void *) rqbiocnt(rq);
 958         }
 959         buf = mempool_alloc(d->bufpool, GFP_ATOMIC);
 960         if (buf == NULL) {
 961                 pr_err("aoe: nextbuf: unable to mempool_alloc!\n");
 962                 return NULL;
 963         }
 964         bio = d->ip.nxbio;
 965         bufinit(buf, rq, bio);
 966         bio = bio->bi_next;
 967         d->ip.nxbio = bio;
 968         if (bio == NULL)
 969                 d->ip.rq = NULL;
 970         return d->ip.buf = buf;
 971 }
 972
 973 /* enters with d->lock held */
 974 void
 975 aoecmd_work(struct aoedev *d)
 976 {
 977         rexmit_deferred(d);
 978         while (aoecmd_ata_rw(d))
 979                 ;
 980 }
 981
 982 /* this function performs work that has been deferred until sleeping is OK
 983  */
 984 void
 985 aoecmd_sleepwork(struct work_struct *work)
 986 {
 987         struct aoedev *d = container_of(work, struct aoedev, work);
 988         struct block_device *bd;
 989         u64 ssize;
 990
 991         if (d->flags & DEVFL_GDALLOC)
 992                 aoeblk_gdalloc(d);
 993
 994         if (d->flags & DEVFL_NEWSIZE) {
 995                 ssize = get_capacity(d->gd);
 996                 bd = bdget_disk(d->gd, 0);
 997                 if (bd) {
 998                         mutex_lock(&bd->bd_inode->i_mutex);
 999                         i_size_write(bd->bd_inode, (loff_t)ssize<<9);
1000                         mutex_unlock(&bd->bd_inode->i_mutex);
1001                         bdput(bd);
1002                 }
1003                 spin_lock_irq(&d->lock);
1004                 d->flags |= DEVFL_UP;
1005                 d->flags &= ~DEVFL_NEWSIZE;
1006                 spin_unlock_irq(&d->lock);
1007         }
1008 }
1009
1010 static void
1011 ata_ident_fixstring(u16 *id, int ns)
1012 {
1013         u16 s;
1014
1015         while (ns-- > 0) {
1016                 s = *id;
1017                 *id++ = s >> 8 | s << 8;
1018         }
1019 }
1020
1021 static void
1022 ataid_complete(struct aoedev *d, struct aoetgt *t, unsigned char *id)
1023 {
1024         u64 ssize;
1025         u16 n;
1026
1027         /* word 83: command set supported */
1028         n = get_unaligned_le16(&id[83 << 1]);
1029
1030         /* word 86: command set/feature enabled */
1031         n |= get_unaligned_le16(&id[86 << 1]);
1032
1033         if (n & (1<<10)) {      /* bit 10: LBA 48 */
1034                 d->flags |= DEVFL_EXT;
1035
1036                 /* word 100: number lba48 sectors */
1037                 ssize = get_unaligned_le64(&id[100 << 1]);
1038
1039                 /* set as in ide-disk.c:init_idedisk_capacity */
1040                 d->geo.cylinders = ssize;
1041                 d->geo.cylinders /= (255 * 63);
1042                 d->geo.heads = 255;
1043                 d->geo.sectors = 63;
1044         } else {
1045                 d->flags &= ~DEVFL_EXT;
1046
1047                 /* number lba28 sectors */
1048                 ssize = get_unaligned_le32(&id[60 << 1]);
1049
1050                 /* NOTE: obsolete in ATA 6 */
1051                 d->geo.cylinders = get_unaligned_le16(&id[54 << 1]);
1052                 d->geo.heads = get_unaligned_le16(&id[55 << 1]);
1053                 d->geo.sectors = get_unaligned_le16(&id[56 << 1]);
1054         }
1055
1056         ata_ident_fixstring((u16 *) &id[10<<1], 10);    /* serial */
1057         ata_ident_fixstring((u16 *) &id[23<<1], 4);     /* firmware */
1058         ata_ident_fixstring((u16 *) &id[27<<1], 20);    /* model */
1059         memcpy(d->ident, id, sizeof(d->ident));
1060
1061         if (d->ssize != ssize)
1062                 printk(KERN_INFO
1063                         "aoe: %pm e%ld.%d v%04x has %llu sectors\n",
1064                         t->addr,
1065                         d->aoemajor, d->aoeminor,
1066                         d->fw_ver, (long long)ssize);
1067         d->ssize = ssize;
1068         d->geo.start = 0;
1069         if (d->flags & (DEVFL_GDALLOC|DEVFL_NEWSIZE))
1070                 return;
1071         if (d->gd != NULL) {
1072                 set_capacity(d->gd, ssize);
1073                 d->flags |= DEVFL_NEWSIZE;
1074         } else
1075                 d->flags |= DEVFL_GDALLOC;
1076         schedule_work(&d->work);
1077 }
1078
1079 static void
1080 calc_rttavg(struct aoedev *d, struct aoetgt *t, int rtt)
1081 {
1082         register long n;
1083
1084         n = rtt;
1085
1086         /* cf. Congestion Avoidance and Control, Jacobson & Karels, 1988 */
1087         n -= d->rttavg >> RTTSCALE;
1088         d->rttavg += n;
1089         if (n < 0)
1090                 n = -n;
1091         n -= d->rttdev >> RTTDSCALE;
1092         d->rttdev += n;
1093
1094         if (!t || t->maxout >= t->nframes)
1095                 return;
1096         if (t->maxout < t->ssthresh)
1097                 t->maxout += 1;
1098         else if (t->nout == t->maxout && t->next_cwnd-- == 0) {
1099                 t->maxout += 1;
1100                 t->next_cwnd = t->maxout;
1101         }
1102 }
1103
1104 static struct aoetgt *
1105 gettgt(struct aoedev *d, char *addr)
1106 {
1107         struct aoetgt **t, **e;
1108
1109         t = d->targets;
1110         e = t + d->ntargets;
1111         for (; t < e && *t; t++)
1112                 if (memcmp((*t)->addr, addr, sizeof((*t)->addr)) == 0)
1113                         return *t;
1114         return NULL;
1115 }
1116
1117 static void
1118 bvcpy(struct bio_vec *bv, ulong off, struct sk_buff *skb, long cnt)
1119 {
1120         ulong fcnt;
1121         char *p;
1122         int soff = 0;
1123 loop:
1124         fcnt = bv->bv_len - (off - bv->bv_offset);
1125         if (fcnt > cnt)
1126                 fcnt = cnt;
1127         p = page_address(bv->bv_page) + off;
1128         skb_copy_bits(skb, soff, p, fcnt);
1129         soff += fcnt;
1130         cnt -= fcnt;
1131         if (cnt <= 0)
1132                 return;
1133         bv++;
1134         off = bv->bv_offset;
1135         goto loop;
1136 }
1137
1138 void
1139 aoe_end_request(struct aoedev *d, struct request *rq, int fastfail)
1140 {
1141         struct bio *bio;
1142         int bok;
1143         struct request_queue *q;
1144
1145         q = d->blkq;
1146         if (rq == d->ip.rq)
1147                 d->ip.rq = NULL;
1148         do {
1149                 bio = rq->bio;
1150                 bok = !fastfail && test_bit(BIO_UPTODATE, &bio->bi_flags);
1151         } while (__blk_end_request(rq, bok ? 0 : -EIO, bio->bi_size));
1152
1153         /* cf. http://lkml.org/lkml/2006/10/31/28 */
1154         if (!fastfail)
1155                 __blk_run_queue(q);
1156 }
1157
1158 static void
1159 aoe_end_buf(struct aoedev *d, struct buf *buf)
1160 {
1161         struct request *rq;
1162         unsigned long n;
1163
1164         if (buf == d->ip.buf)
1165                 d->ip.buf = NULL;
1166         rq = buf->rq;
1167         bio_pagedec(buf->bio);
1168         mempool_free(buf, d->bufpool);
1169         n = (unsigned long) rq->special;
1170         rq->special = (void *) --n;
1171         if (n == 0)
1172                 aoe_end_request(d, rq, 0);
1173 }
1174
1175 static void
1176 ktiocomplete(struct frame *f)
1177 {
1178         struct aoe_hdr *hin, *hout;
1179         struct aoe_atahdr *ahin, *ahout;
1180         struct buf *buf;
1181         struct sk_buff *skb;
1182         struct aoetgt *t;
1183         struct aoeif *ifp;
1184         struct aoedev *d;
1185         long n;
1186         int untainted;
1187
1188         if (f == NULL)
1189                 return;
1190
1191         t = f->t;
1192         d = t->d;
1193         skb = f->r_skb;
1194         buf = f->buf;
1195         if (f->flags & FFL_PROBE)
1196                 goto out;
1197         if (!skb)               /* just fail the buf. */
1198                 goto noskb;
1199
1200         hout = (struct aoe_hdr *) skb_mac_header(f->skb);
1201         ahout = (struct aoe_atahdr *) (hout+1);
1202
1203         hin = (struct aoe_hdr *) skb->data;
1204         skb_pull(skb, sizeof(*hin));
1205         ahin = (struct aoe_atahdr *) skb->data;
1206         skb_pull(skb, sizeof(*ahin));
1207         if (ahin->cmdstat & 0xa9) {     /* these bits cleared on success */
1208                 pr_err("aoe: ata error cmd=%2.2Xh stat=%2.2Xh from e%ld.%d\n",
1209                         ahout->cmdstat, ahin->cmdstat,
1210                         d->aoemajor, d->aoeminor);
1211 noskb:          if (buf)
1212                         clear_bit(BIO_UPTODATE, &buf->bio->bi_flags);
1213                 goto out;
1214         }
1215
1216         n = ahout->scnt << 9;
1217         switch (ahout->cmdstat) {
1218         case ATA_CMD_PIO_READ:
1219         case ATA_CMD_PIO_READ_EXT:
1220                 if (skb->len < n) {
1221                         pr_err("%s e%ld.%d.  skb->len=%d need=%ld\n",
1222                                 "aoe: runt data size in read from",
1223                                 (long) d->aoemajor, d->aoeminor,
1224                                skb->len, n);
1225                         clear_bit(BIO_UPTODATE, &buf->bio->bi_flags);
1226                         break;
1227                 }
1228                 bvcpy(f->bv, f->bv_off, skb, n);
1229         case ATA_CMD_PIO_WRITE:
1230         case ATA_CMD_PIO_WRITE_EXT:
1231                 spin_lock_irq(&d->lock);
1232                 ifp = getif(t, skb->dev);
1233                 if (ifp)
1234                         ifp->lost = 0;
1235                 spin_unlock_irq(&d->lock);
1236                 break;
1237         case ATA_CMD_ID_ATA:
1238                 if (skb->len < 512) {
1239                         pr_info("%s e%ld.%d.  skb->len=%d need=512\n",
1240                                 "aoe: runt data size in ataid from",
1241                                 (long) d->aoemajor, d->aoeminor,
1242                                 skb->len);
1243                         break;
1244                 }
1245                 if (skb_linearize(skb))
1246                         break;
1247                 spin_lock_irq(&d->lock);
1248                 ataid_complete(d, t, skb->data);
1249                 spin_unlock_irq(&d->lock);
1250                 break;
1251         default:
1252                 pr_info("aoe: unrecognized ata command %2.2Xh for %d.%d\n",
1253                         ahout->cmdstat,
1254                         be16_to_cpu(get_unaligned(&hin->major)),
1255                         hin->minor);
1256         }
1257 out:
1258         spin_lock_irq(&d->lock);
1259         if (t->taint > 0
1260         && --t->taint > 0
1261         && t->nout_probes == 0) {
1262                 count_targets(d, &untainted);
1263                 if (untainted > 0) {
1264                         probe(t);
1265                         t->nout_probes++;
1266                 }
1267         }
1268
1269         aoe_freetframe(f);
1270
1271         if (buf && --buf->nframesout == 0 && buf->resid == 0)
1272                 aoe_end_buf(d, buf);
1273
1274         spin_unlock_irq(&d->lock);
1275         aoedev_put(d);
1276         dev_kfree_skb(skb);
1277 }
1278
1279 /* Enters with iocq.lock held.
1280  * Returns true iff responses needing processing remain.
1281  */
1282 static int
1283 ktio(void)
1284 {
1285         struct frame *f;
1286         struct list_head *pos;
1287         int i;
1288
1289         for (i = 0; ; ++i) {
1290                 if (i == MAXIOC)
1291                         return 1;
1292                 if (list_empty(&iocq.head))
1293                         return 0;
1294                 pos = iocq.head.next;
1295                 list_del(pos);
1296                 spin_unlock_irq(&iocq.lock);
1297                 f = list_entry(pos, struct frame, head);
1298                 ktiocomplete(f);
1299                 spin_lock_irq(&iocq.lock);
1300         }
1301 }
1302
1303 static int
1304 kthread(void *vp)
1305 {
1306         struct ktstate *k;
1307         DECLARE_WAITQUEUE(wait, current);
1308         int more;
1309
1310         k = vp;
1311         current->flags |= PF_NOFREEZE;
1312         set_user_nice(current, -10);
1313         complete(&k->rendez);   /* tell spawner we're running */
1314         do {
1315                 spin_lock_irq(k->lock);
1316                 more = k->fn();
1317                 if (!more) {
1318                         add_wait_queue(k->waitq, &wait);
1319                         __set_current_state(TASK_INTERRUPTIBLE);
1320                 }
1321                 spin_unlock_irq(k->lock);
1322                 if (!more) {
1323                         schedule();
1324                         remove_wait_queue(k->waitq, &wait);
1325                 } else
1326                         cond_resched();
1327         } while (!kthread_should_stop());
1328         complete(&k->rendez);   /* tell spawner we're stopping */
1329         return 0;
1330 }
1331
1332 void
1333 aoe_ktstop(struct ktstate *k)
1334 {
1335         kthread_stop(k->task);
1336         wait_for_completion(&k->rendez);
1337 }
1338
1339 int
1340 aoe_ktstart(struct ktstate *k)
1341 {
1342         struct task_struct *task;
1343
1344         init_completion(&k->rendez);
1345         task = kthread_run(kthread, k, k->name);
1346         if (task == NULL || IS_ERR(task))
1347                 return -ENOMEM;
1348         k->task = task;
1349         wait_for_completion(&k->rendez); /* allow kthread to start */
1350         init_completion(&k->rendez);    /* for waiting for exit later */
1351         return 0;
1352 }
1353
1354 /* pass it off to kthreads for processing */
1355 static void
1356 ktcomplete(struct frame *f, struct sk_buff *skb)
1357 {
1358         ulong flags;
1359
1360         f->r_skb = skb;
1361         spin_lock_irqsave(&iocq.lock, flags);
1362         list_add_tail(&f->head, &iocq.head);
1363         spin_unlock_irqrestore(&iocq.lock, flags);
1364         wake_up(&ktiowq);
1365 }
1366
1367 struct sk_buff *
1368 aoecmd_ata_rsp(struct sk_buff *skb)
1369 {
1370         struct aoedev *d;
1371         struct aoe_hdr *h;
1372         struct frame *f;
1373         u32 n;
1374         ulong flags;
1375         char ebuf[128];
1376         u16 aoemajor;
1377
1378         h = (struct aoe_hdr *) skb->data;
1379         aoemajor = be16_to_cpu(get_unaligned(&h->major));
1380         d = aoedev_by_aoeaddr(aoemajor, h->minor, 0);
1381         if (d == NULL) {
1382                 snprintf(ebuf, sizeof ebuf, "aoecmd_ata_rsp: ata response "
1383                         "for unknown device %d.%d\n",
1384                         aoemajor, h->minor);
1385                 aoechr_error(ebuf);
1386                 return skb;
1387         }
1388
1389         spin_lock_irqsave(&d->lock, flags);
1390
1391         n = be32_to_cpu(get_unaligned(&h->tag));
1392         f = getframe(d, n);
1393         if (f) {
1394                 calc_rttavg(d, f->t, tsince_hr(f));
1395                 f->t->nout--;
1396                 if (f->flags & FFL_PROBE)
1397                         f->t->nout_probes--;
1398         } else {
1399                 f = getframe_deferred(d, n);
1400                 if (f) {
1401                         calc_rttavg(d, NULL, tsince_hr(f));
1402                 } else {
1403                         calc_rttavg(d, NULL, tsince(n));
1404                         spin_unlock_irqrestore(&d->lock, flags);
1405                         aoedev_put(d);
1406                         snprintf(ebuf, sizeof(ebuf),
1407                                  "%15s e%d.%d    tag=%08x@%08lx s=%pm d=%pm\n",
1408                                  "unexpected rsp",
1409                                  get_unaligned_be16(&h->major),
1410                                  h->minor,
1411                                  get_unaligned_be32(&h->tag),
1412                                  jiffies,
1413                                  h->src,
1414                                  h->dst);
1415                         aoechr_error(ebuf);
1416                         return skb;
1417                 }
1418         }
1419         aoecmd_work(d);
1420
1421         spin_unlock_irqrestore(&d->lock, flags);
1422
1423         ktcomplete(f, skb);
1424
1425         /*
1426          * Note here that we do not perform an aoedev_put, as we are
1427          * leaving this reference for the ktio to release.
1428          */
1429         return NULL;
1430 }
1431
1432 void
1433 aoecmd_cfg(ushort aoemajor, unsigned char aoeminor)
1434 {
1435         struct sk_buff_head queue;
1436
1437         __skb_queue_head_init(&queue);
1438         aoecmd_cfg_pkts(aoemajor, aoeminor, &queue);
1439         aoenet_xmit(&queue);
1440 }
1441
1442 struct sk_buff *
1443 aoecmd_ata_id(struct aoedev *d)
1444 {
1445         struct aoe_hdr *h;
1446         struct aoe_atahdr *ah;
1447         struct frame *f;
1448         struct sk_buff *skb;
1449         struct aoetgt *t;
1450
1451         f = newframe(d);
1452         if (f == NULL)
1453                 return NULL;
1454
1455         t = *d->tgt;
1456
1457         /* initialize the headers & frame */
1458         skb = f->skb;
1459         h = (struct aoe_hdr *) skb_mac_header(skb);
1460         ah = (struct aoe_atahdr *) (h+1);
1461         skb_put(skb, sizeof *h + sizeof *ah);
1462         memset(h, 0, skb->len);
1463         f->tag = aoehdr_atainit(d, t, h);
1464         fhash(f);
1465         t->nout++;
1466         f->waited = 0;
1467         f->waited_total = 0;
1468
1469         /* set up ata header */
1470         ah->scnt = 1;
1471         ah->cmdstat = ATA_CMD_ID_ATA;
1472         ah->lba3 = 0xa0;
1473
1474         skb->dev = t->ifp->nd;
1475
1476         d->rttavg = RTTAVG_INIT;
1477         d->rttdev = RTTDEV_INIT;
1478         d->timer.function = rexmit_timer;
1479
1480         skb = skb_clone(skb, GFP_ATOMIC);
1481         if (skb) {
1482                 do_gettimeofday(&f->sent);
1483                 f->sent_jiffs = (u32) jiffies;
1484         }
1485
1486         return skb;
1487 }
1488
1489 static struct aoetgt **
1490 grow_targets(struct aoedev *d)
1491 {
1492         ulong oldn, newn;
1493         struct aoetgt **tt;
1494
1495         oldn = d->ntargets;
1496         newn = oldn * 2;
1497         tt = kcalloc(newn, sizeof(*d->targets), GFP_ATOMIC);
1498         if (!tt)
1499                 return NULL;
1500         memmove(tt, d->targets, sizeof(*d->targets) * oldn);
1501         d->tgt = tt + (d->tgt - d->targets);
1502         kfree(d->targets);
1503         d->targets = tt;
1504         d->ntargets = newn;
1505
1506         return &d->targets[oldn];
1507 }
1508
1509 static struct aoetgt *
1510 addtgt(struct aoedev *d, char *addr, ulong nframes)
1511 {
1512         struct aoetgt *t, **tt, **te;
1513
1514         tt = d->targets;
1515         te = tt + d->ntargets;
1516         for (; tt < te && *tt; tt++)
1517                 ;
1518
1519         if (tt == te) {
1520                 tt = grow_targets(d);
1521                 if (!tt)
1522                         goto nomem;
1523         }
1524         t = kzalloc(sizeof(*t), GFP_ATOMIC);
1525         if (!t)
1526                 goto nomem;
1527         t->nframes = nframes;
1528         t->d = d;
1529         memcpy(t->addr, addr, sizeof t->addr);
1530         t->ifp = t->ifs;
1531         aoecmd_wreset(t);
1532         t->maxout = t->nframes / 2;
1533         INIT_LIST_HEAD(&t->ffree);
1534         return *tt = t;
1535
1536  nomem:
1537         pr_info("aoe: cannot allocate memory to add target\n");
1538         return NULL;
1539 }
1540
1541 static void
1542 setdbcnt(struct aoedev *d)
1543 {
1544         struct aoetgt **t, **e;
1545         int bcnt = 0;
1546
1547         t = d->targets;
1548         e = t + d->ntargets;
1549         for (; t < e && *t; t++)
1550                 if (bcnt == 0 || bcnt > (*t)->minbcnt)
1551                         bcnt = (*t)->minbcnt;
1552         if (bcnt != d->maxbcnt) {
1553                 d->maxbcnt = bcnt;
1554                 pr_info("aoe: e%ld.%d: setting %d byte data frames\n",
1555                         d->aoemajor, d->aoeminor, bcnt);
1556         }
1557 }
1558
1559 static void
1560 setifbcnt(struct aoetgt *t, struct net_device *nd, int bcnt)
1561 {
1562         struct aoedev *d;
1563         struct aoeif *p, *e;
1564         int minbcnt;
1565
1566         d = t->d;
1567         minbcnt = bcnt;
1568         p = t->ifs;
1569         e = p + NAOEIFS;
1570         for (; p < e; p++) {
1571                 if (p->nd == NULL)
1572                         break;          /* end of the valid interfaces */
1573                 if (p->nd == nd) {
1574                         p->bcnt = bcnt; /* we're updating */
1575                         nd = NULL;
1576                 } else if (minbcnt > p->bcnt)
1577                         minbcnt = p->bcnt; /* find the min interface */
1578         }
1579         if (nd) {
1580                 if (p == e) {
1581                         pr_err("aoe: device setifbcnt failure; too many interfaces.\n");
1582                         return;
1583                 }
1584                 dev_hold(nd);
1585                 p->nd = nd;
1586                 p->bcnt = bcnt;
1587         }
1588         t->minbcnt = minbcnt;
1589         setdbcnt(d);
1590 }
1591
1592 void
1593 aoecmd_cfg_rsp(struct sk_buff *skb)
1594 {
1595         struct aoedev *d;
1596         struct aoe_hdr *h;
1597         struct aoe_cfghdr *ch;
1598         struct aoetgt *t;
1599         ulong flags, aoemajor;
1600         struct sk_buff *sl;
1601         struct sk_buff_head queue;
1602         u16 n;
1603
1604         sl = NULL;
1605         h = (struct aoe_hdr *) skb_mac_header(skb);
1606         ch = (struct aoe_cfghdr *) (h+1);
1607
1608         /*
1609          * Enough people have their dip switches set backwards to
1610          * warrant a loud message for this special case.
1611          */
1612         aoemajor = get_unaligned_be16(&h->major);
1613         if (aoemajor == 0xfff) {
1614                 printk(KERN_ERR "aoe: Warning: shelf address is all ones.  "
1615                         "Check shelf dip switches.\n");
1616                 return;
1617         }
1618         if (aoemajor == 0xffff) {
1619                 pr_info("aoe: e%ld.%d: broadcast shelf number invalid\n",
1620                         aoemajor, (int) h->minor);
1621                 return;
1622         }
1623         if (h->minor == 0xff) {
1624                 pr_info("aoe: e%ld.%d: broadcast slot number invalid\n",
1625                         aoemajor, (int) h->minor);
1626                 return;
1627         }
1628
1629         n = be16_to_cpu(ch->bufcnt);
1630         if (n > aoe_maxout)     /* keep it reasonable */
1631                 n = aoe_maxout;
1632
1633         d = aoedev_by_aoeaddr(aoemajor, h->minor, 1);
1634         if (d == NULL) {
1635                 pr_info("aoe: device allocation failure\n");
1636                 return;
1637         }
1638
1639         spin_lock_irqsave(&d->lock, flags);
1640
1641         t = gettgt(d, h->src);
1642         if (t) {
1643                 t->nframes = n;
1644                 if (n < t->maxout)
1645                         aoecmd_wreset(t);
1646         } else {
1647                 t = addtgt(d, h->src, n);
1648                 if (!t)
1649                         goto bail;
1650         }
1651         n = skb->dev->mtu;
1652         n -= sizeof(struct aoe_hdr) + sizeof(struct aoe_atahdr);
1653         n /= 512;
1654         if (n > ch->scnt)
1655                 n = ch->scnt;
1656         n = n ? n * 512 : DEFAULTBCNT;
1657         setifbcnt(t, skb->dev, n);
1658
1659         /* don't change users' perspective */
1660         if (d->nopen == 0) {
1661                 d->fw_ver = be16_to_cpu(ch->fwver);
1662                 sl = aoecmd_ata_id(d);
1663         }
1664 bail:
1665         spin_unlock_irqrestore(&d->lock, flags);
1666         aoedev_put(d);
1667         if (sl) {
1668                 __skb_queue_head_init(&queue);
1669                 __skb_queue_tail(&queue, sl);
1670                 aoenet_xmit(&queue);
1671         }
1672 }
1673
1674 void
1675 aoecmd_wreset(struct aoetgt *t)
1676 {
1677         t->maxout = 1;
1678         t->ssthresh = t->nframes / 2;
1679         t->next_cwnd = t->nframes;
1680 }
1681
1682 void
1683 aoecmd_cleanslate(struct aoedev *d)
1684 {
1685         struct aoetgt **t, **te;
1686
1687         d->rttavg = RTTAVG_INIT;
1688         d->rttdev = RTTDEV_INIT;
1689         d->maxbcnt = 0;
1690
1691         t = d->targets;
1692         te = t + d->ntargets;
1693         for (; t < te && *t; t++)
1694                 aoecmd_wreset(*t);
1695 }
1696
1697 void
1698 aoe_failbuf(struct aoedev *d, struct buf *buf)
1699 {
1700         if (buf == NULL)
1701                 return;
1702         buf->resid = 0;
1703         clear_bit(BIO_UPTODATE, &buf->bio->bi_flags);
1704         if (buf->nframesout == 0)
1705                 aoe_end_buf(d, buf);
1706 }
1707
1708 void
1709 aoe_flush_iocq(void)
1710 {
1711         struct frame *f;
1712         struct aoedev *d;
1713         LIST_HEAD(flist);
1714         struct list_head *pos;
1715         struct sk_buff *skb;
1716         ulong flags;
1717
1718         spin_lock_irqsave(&iocq.lock, flags);
1719         list_splice_init(&iocq.head, &flist);
1720         spin_unlock_irqrestore(&iocq.lock, flags);
1721         while (!list_empty(&flist)) {
1722                 pos = flist.next;
1723                 list_del(pos);
1724                 f = list_entry(pos, struct frame, head);
1725                 d = f->t->d;
1726                 skb = f->r_skb;
1727                 spin_lock_irqsave(&d->lock, flags);
1728                 if (f->buf) {
1729                         f->buf->nframesout--;
1730                         aoe_failbuf(d, f->buf);
1731                 }
1732                 aoe_freetframe(f);
1733                 spin_unlock_irqrestore(&d->lock, flags);
1734                 dev_kfree_skb(skb);
1735                 aoedev_put(d);
1736         }
1737 }
1738
1739 int __init
1740 aoecmd_init(void)
1741 {
1742         void *p;
1743
1744         /* get_zeroed_page returns page with ref count 1 */
1745         p = (void *) get_zeroed_page(GFP_KERNEL | __GFP_REPEAT);
1746         if (!p)
1747                 return -ENOMEM;
1748         empty_page = virt_to_page(p);
1749
1750         INIT_LIST_HEAD(&iocq.head);
1751         spin_lock_init(&iocq.lock);
1752         init_waitqueue_head(&ktiowq);
1753         kts.name = "aoe_ktio";
1754         kts.fn = ktio;
1755         kts.waitq = &ktiowq;
1756         kts.lock = &iocq.lock;
1757         return aoe_ktstart(&kts);
1758 }
1759
1760 void
1761 aoecmd_exit(void)
1762 {
1763         aoe_ktstop(&kts);
1764         aoe_flush_iocq();
1765
1766         free_page((unsigned long) page_address(empty_page));
1767         empty_page = NULL;
1768 }