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