drivers/block/aoe/aoedev.c

   1 /* Copyright (c) 2013 Coraid, Inc.  See COPYING for GPL terms. */
   2 /*
   3  * aoedev.c
   4  * AoE device utility functions; maintains device list.
   5  */
   6
   7 #include <linux/hdreg.h>
   8 #include <linux/blkdev.h>
   9 #include <linux/netdevice.h>
  10 #include <linux/delay.h>
  11 #include <linux/slab.h>
  12 #include <linux/bitmap.h>
  13 #include <linux/kdev_t.h>
  14 #include <linux/moduleparam.h>
  15 #include <linux/string.h>
  16 #include "aoe.h"
  17
  18 static void dummy_timer(ulong);
  19 static void freetgt(struct aoedev *d, struct aoetgt *t);
  20 static void skbpoolfree(struct aoedev *d);
  21
  22 static int aoe_dyndevs = 1;
  23 module_param(aoe_dyndevs, int, 0644);
  24 MODULE_PARM_DESC(aoe_dyndevs, "Use dynamic minor numbers for devices.");
  25
  26 static struct aoedev *devlist;
  27 static DEFINE_SPINLOCK(devlist_lock);
  28
  29 /* Because some systems will have one, many, or no
  30  *   - partitions,
  31  *   - slots per shelf,
  32  *   - or shelves,
  33  * we need some flexibility in the way the minor numbers
  34  * are allocated.  So they are dynamic.
  35  */
  36 #define N_DEVS ((1U<<MINORBITS)/AOE_PARTITIONS)
  37
  38 static DEFINE_SPINLOCK(used_minors_lock);
  39 static DECLARE_BITMAP(used_minors, N_DEVS);
  40
  41 static int
  42 minor_get_dyn(ulong *sysminor)
  43 {
  44         ulong flags;
  45         ulong n;
  46         int error = 0;
  47
  48         spin_lock_irqsave(&used_minors_lock, flags);
  49         n = find_first_zero_bit(used_minors, N_DEVS);
  50         if (n < N_DEVS)
  51                 set_bit(n, used_minors);
  52         else
  53                 error = -1;
  54         spin_unlock_irqrestore(&used_minors_lock, flags);
  55
  56         *sysminor = n * AOE_PARTITIONS;
  57         return error;
  58 }
  59
  60 static int
  61 minor_get_static(ulong *sysminor, ulong aoemaj, int aoemin)
  62 {
  63         ulong flags;
  64         ulong n;
  65         int error = 0;
  66         enum {
  67                 /* for backwards compatibility when !aoe_dyndevs,
  68                  * a static number of supported slots per shelf */
  69                 NPERSHELF = 16,
  70         };
  71
  72         if (aoemin >= NPERSHELF) {
  73                 pr_err("aoe: %s %d slots per shelf\n",
  74                         "static minor device numbers support only",
  75                         NPERSHELF);
  76                 error = -1;
  77                 goto out;
  78         }
  79
  80         n = aoemaj * NPERSHELF + aoemin;
  81         if (n >= N_DEVS) {
  82                 pr_err("aoe: %s with e%ld.%d\n",
  83                         "cannot use static minor device numbers",
  84                         aoemaj, aoemin);
  85                 error = -1;
  86                 goto out;
  87         }
  88
  89         spin_lock_irqsave(&used_minors_lock, flags);
  90         if (test_bit(n, used_minors)) {
  91                 pr_err("aoe: %s %lu\n",
  92                         "existing device already has static minor number",
  93                         n);
  94                 error = -1;
  95         } else
  96                 set_bit(n, used_minors);
  97         spin_unlock_irqrestore(&used_minors_lock, flags);
  98         *sysminor = n * AOE_PARTITIONS;
  99 out:
 100         return error;
 101 }
 102
 103 static int
 104 minor_get(ulong *sysminor, ulong aoemaj, int aoemin)
 105 {
 106         if (aoe_dyndevs)
 107                 return minor_get_dyn(sysminor);
 108         else
 109                 return minor_get_static(sysminor, aoemaj, aoemin);
 110 }
 111
 112 static void
 113 minor_free(ulong minor)
 114 {
 115         ulong flags;
 116
 117         minor /= AOE_PARTITIONS;
 118         BUG_ON(minor >= N_DEVS);
 119
 120         spin_lock_irqsave(&used_minors_lock, flags);
 121         BUG_ON(!test_bit(minor, used_minors));
 122         clear_bit(minor, used_minors);
 123         spin_unlock_irqrestore(&used_minors_lock, flags);
 124 }
 125
 126 /*
 127  * Users who grab a pointer to the device with aoedev_by_aoeaddr
 128  * automatically get a reference count and must be responsible
 129  * for performing a aoedev_put.  With the addition of async
 130  * kthread processing I'm no longer confident that we can
 131  * guarantee consistency in the face of device flushes.
 132  *
 133  * For the time being, we only bother to add extra references for
 134  * frames sitting on the iocq.  When the kthreads finish processing
 135  * these frames, they will aoedev_put the device.
 136  */
 137
 138 void
 139 aoedev_put(struct aoedev *d)
 140 {
 141         ulong flags;
 142
 143         spin_lock_irqsave(&devlist_lock, flags);
 144         d->ref--;
 145         spin_unlock_irqrestore(&devlist_lock, flags);
 146 }
 147
 148 static void
 149 dummy_timer(ulong vp)
 150 {
 151         struct aoedev *d;
 152
 153         d = (struct aoedev *)vp;
 154         if (d->flags & DEVFL_TKILL)
 155                 return;
 156         d->timer.expires = jiffies + HZ;
 157         add_timer(&d->timer);
 158 }
 159
 160 static void
 161 aoe_failip(struct aoedev *d)
 162 {
 163         struct request *rq;
 164         struct bio *bio;
 165         unsigned long n;
 166
 167         aoe_failbuf(d, d->ip.buf);
 168
 169         rq = d->ip.rq;
 170         if (rq == NULL)
 171                 return;
 172         while ((bio = d->ip.nxbio)) {
 173                 bio->bi_status = BLK_STS_IOERR;
 174                 d->ip.nxbio = bio->bi_next;
 175                 n = (unsigned long) rq->special;
 176                 rq->special = (void *) --n;
 177         }
 178         if ((unsigned long) rq->special == 0)
 179                 aoe_end_request(d, rq, 0);
 180 }
 181
 182 static void
 183 downdev_frame(struct list_head *pos)
 184 {
 185         struct frame *f;
 186
 187         f = list_entry(pos, struct frame, head);
 188         list_del(pos);
 189         if (f->buf) {
 190                 f->buf->nframesout--;
 191                 aoe_failbuf(f->t->d, f->buf);
 192         }
 193         aoe_freetframe(f);
 194 }
 195
 196 void
 197 aoedev_downdev(struct aoedev *d)
 198 {
 199         struct aoetgt *t, **tt, **te;
 200         struct list_head *head, *pos, *nx;
 201         struct request *rq;
 202         int i;
 203
 204         d->flags &= ~DEVFL_UP;
 205
 206         /* clean out active and to-be-retransmitted buffers */
 207         for (i = 0; i < NFACTIVE; i++) {
 208                 head = &d->factive[i];
 209                 list_for_each_safe(pos, nx, head)
 210                         downdev_frame(pos);
 211         }
 212         head = &d->rexmitq;
 213         list_for_each_safe(pos, nx, head)
 214                 downdev_frame(pos);
 215
 216         /* reset window dressings */
 217         tt = d->targets;
 218         te = tt + d->ntargets;
 219         for (; tt < te && (t = *tt); tt++) {
 220                 aoecmd_wreset(t);
 221                 t->nout = 0;
 222         }
 223
 224         /* clean out the in-process request (if any) */
 225         aoe_failip(d);
 226
 227         /* fast fail all pending I/O */
 228         if (d->blkq) {
 229                 while ((rq = blk_peek_request(d->blkq))) {
 230                         blk_start_request(rq);
 231                         aoe_end_request(d, rq, 1);
 232                 }
 233         }
 234
 235         if (d->gd)
 236                 set_capacity(d->gd, 0);
 237 }
 238
 239 /* return whether the user asked for this particular
 240  * device to be flushed
 241  */
 242 static int
 243 user_req(char *s, size_t slen, struct aoedev *d)
 244 {
 245         const char *p;
 246         size_t lim;
 247
 248         if (!d->gd)
 249                 return 0;
 250         p = kbasename(d->gd->disk_name);
 251         lim = sizeof(d->gd->disk_name);
 252         lim -= p - d->gd->disk_name;
 253         if (slen < lim)
 254                 lim = slen;
 255
 256         return !strncmp(s, p, lim);
 257 }
 258
 259 static void
 260 freedev(struct aoedev *d)
 261 {
 262         struct aoetgt **t, **e;
 263         int freeing = 0;
 264         unsigned long flags;
 265
 266         spin_lock_irqsave(&d->lock, flags);
 267         if (d->flags & DEVFL_TKILL
 268         && !(d->flags & DEVFL_FREEING)) {
 269                 d->flags |= DEVFL_FREEING;
 270                 freeing = 1;
 271         }
 272         spin_unlock_irqrestore(&d->lock, flags);
 273         if (!freeing)
 274                 return;
 275
 276         del_timer_sync(&d->timer);
 277         if (d->gd) {
 278                 aoedisk_rm_debugfs(d);
 279                 aoedisk_rm_sysfs(d);
 280                 del_gendisk(d->gd);
 281                 put_disk(d->gd);
 282                 blk_cleanup_queue(d->blkq);
 283         }
 284         t = d->targets;
 285         e = t + d->ntargets;
 286         for (; t < e && *t; t++)
 287                 freetgt(d, *t);
 288         if (d->bufpool)
 289                 mempool_destroy(d->bufpool);
 290         skbpoolfree(d);
 291         minor_free(d->sysminor);
 292
 293         spin_lock_irqsave(&d->lock, flags);
 294         d->flags |= DEVFL_FREED;
 295         spin_unlock_irqrestore(&d->lock, flags);
 296 }
 297
 298 enum flush_parms {
 299         NOT_EXITING = 0,
 300         EXITING = 1,
 301 };
 302
 303 static int
 304 flush(const char __user *str, size_t cnt, int exiting)
 305 {
 306         ulong flags;
 307         struct aoedev *d, **dd;
 308         char buf[16];
 309         int all = 0;
 310         int specified = 0;      /* flush a specific device */
 311         unsigned int skipflags;
 312
 313         skipflags = DEVFL_GDALLOC | DEVFL_NEWSIZE | DEVFL_TKILL;
 314
 315         if (!exiting && cnt >= 3) {
 316                 if (cnt > sizeof buf)
 317                         cnt = sizeof buf;
 318                 if (copy_from_user(buf, str, cnt))
 319                         return -EFAULT;
 320                 all = !strncmp(buf, "all", 3);
 321                 if (!all)
 322                         specified = 1;
 323         }
 324
 325         flush_scheduled_work();
 326         /* pass one: without sleeping, do aoedev_downdev */
 327         spin_lock_irqsave(&devlist_lock, flags);
 328         for (d = devlist; d; d = d->next) {
 329                 spin_lock(&d->lock);
 330                 if (exiting) {
 331                         /* unconditionally take each device down */
 332                 } else if (specified) {
 333                         if (!user_req(buf, cnt, d))
 334                                 goto cont;
 335                 } else if ((!all && (d->flags & DEVFL_UP))
 336                 || d->flags & skipflags
 337                 || d->nopen
 338                 || d->ref)
 339                         goto cont;
 340
 341                 aoedev_downdev(d);
 342                 d->flags |= DEVFL_TKILL;
 343 cont:
 344                 spin_unlock(&d->lock);
 345         }
 346         spin_unlock_irqrestore(&devlist_lock, flags);
 347
 348         /* pass two: call freedev, which might sleep,
 349          * for aoedevs marked with DEVFL_TKILL
 350          */
 351 restart:
 352         spin_lock_irqsave(&devlist_lock, flags);
 353         for (d = devlist; d; d = d->next) {
 354                 spin_lock(&d->lock);
 355                 if (d->flags & DEVFL_TKILL
 356                 && !(d->flags & DEVFL_FREEING)) {
 357                         spin_unlock(&d->lock);
 358                         spin_unlock_irqrestore(&devlist_lock, flags);
 359                         freedev(d);
 360                         goto restart;
 361                 }
 362                 spin_unlock(&d->lock);
 363         }
 364
 365         /* pass three: remove aoedevs marked with DEVFL_FREED */
 366         for (dd = &devlist, d = *dd; d; d = *dd) {
 367                 struct aoedev *doomed = NULL;
 368
 369                 spin_lock(&d->lock);
 370                 if (d->flags & DEVFL_FREED) {
 371                         *dd = d->next;
 372                         doomed = d;
 373                 } else {
 374                         dd = &d->next;
 375                 }
 376                 spin_unlock(&d->lock);
 377                 if (doomed)
 378                         kfree(doomed->targets);
 379                 kfree(doomed);
 380         }
 381         spin_unlock_irqrestore(&devlist_lock, flags);
 382
 383         return 0;
 384 }
 385
 386 int
 387 aoedev_flush(const char __user *str, size_t cnt)
 388 {
 389         return flush(str, cnt, NOT_EXITING);
 390 }
 391
 392 /* This has been confirmed to occur once with Tms=3*1000 due to the
 393  * driver changing link and not processing its transmit ring.  The
 394  * problem is hard enough to solve by returning an error that I'm
 395  * still punting on "solving" this.
 396  */
 397 static void
 398 skbfree(struct sk_buff *skb)
 399 {
 400         enum { Sms = 250, Tms = 30 * 1000};
 401         int i = Tms / Sms;
 402
 403         if (skb == NULL)
 404                 return;
 405         while (atomic_read(&skb_shinfo(skb)->dataref) != 1 && i-- > 0)
 406                 msleep(Sms);
 407         if (i < 0) {
 408                 printk(KERN_ERR
 409                         "aoe: %s holds ref: %s\n",
 410                         skb->dev ? skb->dev->name : "netif",
 411                         "cannot free skb -- memory leaked.");
 412                 return;
 413         }
 414         skb->truesize -= skb->data_len;
 415         skb_shinfo(skb)->nr_frags = skb->data_len = 0;
 416         skb_trim(skb, 0);
 417         dev_kfree_skb(skb);
 418 }
 419
 420 static void
 421 skbpoolfree(struct aoedev *d)
 422 {
 423         struct sk_buff *skb, *tmp;
 424
 425         skb_queue_walk_safe(&d->skbpool, skb, tmp)
 426                 skbfree(skb);
 427
 428         __skb_queue_head_init(&d->skbpool);
 429 }
 430
 431 /* find it or allocate it */
 432 struct aoedev *
 433 aoedev_by_aoeaddr(ulong maj, int min, int do_alloc)
 434 {
 435         struct aoedev *d;
 436         int i;
 437         ulong flags;
 438         ulong sysminor = 0;
 439
 440         spin_lock_irqsave(&devlist_lock, flags);
 441
 442         for (d=devlist; d; d=d->next)
 443                 if (d->aoemajor == maj && d->aoeminor == min) {
 444                         spin_lock(&d->lock);
 445                         if (d->flags & DEVFL_TKILL) {
 446                                 spin_unlock(&d->lock);
 447                                 d = NULL;
 448                                 goto out;
 449                         }
 450                         d->ref++;
 451                         spin_unlock(&d->lock);
 452                         break;
 453                 }
 454         if (d || !do_alloc || minor_get(&sysminor, maj, min) < 0)
 455                 goto out;
 456         d = kcalloc(1, sizeof *d, GFP_ATOMIC);
 457         if (!d)
 458                 goto out;
 459         d->targets = kcalloc(NTARGETS, sizeof(*d->targets), GFP_ATOMIC);
 460         if (!d->targets) {
 461                 kfree(d);
 462                 d = NULL;
 463                 goto out;
 464         }
 465         d->ntargets = NTARGETS;
 466         INIT_WORK(&d->work, aoecmd_sleepwork);
 467         spin_lock_init(&d->lock);
 468         skb_queue_head_init(&d->skbpool);
 469         init_timer(&d->timer);
 470         d->timer.data = (ulong) d;
 471         d->timer.function = dummy_timer;
 472         d->timer.expires = jiffies + HZ;
 473         add_timer(&d->timer);
 474         d->bufpool = NULL;      /* defer to aoeblk_gdalloc */
 475         d->tgt = d->targets;
 476         d->ref = 1;
 477         for (i = 0; i < NFACTIVE; i++)
 478                 INIT_LIST_HEAD(&d->factive[i]);
 479         INIT_LIST_HEAD(&d->rexmitq);
 480         d->sysminor = sysminor;
 481         d->aoemajor = maj;
 482         d->aoeminor = min;
 483         d->rttavg = RTTAVG_INIT;
 484         d->rttdev = RTTDEV_INIT;
 485         d->next = devlist;
 486         devlist = d;
 487  out:
 488         spin_unlock_irqrestore(&devlist_lock, flags);
 489         return d;
 490 }
 491
 492 static void
 493 freetgt(struct aoedev *d, struct aoetgt *t)
 494 {
 495         struct frame *f;
 496         struct list_head *pos, *nx, *head;
 497         struct aoeif *ifp;
 498
 499         for (ifp = t->ifs; ifp < &t->ifs[NAOEIFS]; ++ifp) {
 500                 if (!ifp->nd)
 501                         break;
 502                 dev_put(ifp->nd);
 503         }
 504
 505         head = &t->ffree;
 506         list_for_each_safe(pos, nx, head) {
 507                 list_del(pos);
 508                 f = list_entry(pos, struct frame, head);
 509                 skbfree(f->skb);
 510                 kfree(f);
 511         }
 512         kfree(t);
 513 }
 514
 515 void
 516 aoedev_exit(void)
 517 {
 518         flush_scheduled_work();
 519         flush(NULL, 0, EXITING);
 520 }
 521
 522 int __init
 523 aoedev_init(void)
 524 {
 525         return 0;
 526 }