sys/dev/disk/md/md.c

   1 /*
   2  * ----------------------------------------------------------------------------
   3  * "THE BEER-WARE LICENSE" (Revision 42):
   4  * <phk@FreeBSD.ORG> wrote this file.  As long as you retain this notice you
   5  * can do whatever you want with this stuff. If we meet some day, and you think
   6  * this stuff is worth it, you can buy me a beer in return.   Poul-Henning Kamp
   7  * ----------------------------------------------------------------------------
   8  *
   9  * $FreeBSD: src/sys/dev/md/md.c,v 1.8.2.2 2002/08/19 17:43:34 jdp Exp $
  10  * $DragonFly: src/sys/dev/disk/md/md.c,v 1.20 2008/09/07 08:09:39 swildner Exp $
  11  *
  12  */
  13
  14 #include "opt_md.h"             /* We have adopted some tasks from MFS */
  15
  16 #include <sys/param.h>
  17 #include <sys/systm.h>
  18 #include <sys/buf.h>
  19 #include <sys/conf.h>
  20 #include <sys/devicestat.h>
  21 #include <sys/disk.h>
  22 #include <sys/kernel.h>
  23 #include <sys/malloc.h>
  24 #include <sys/sysctl.h>
  25 #include <sys/linker.h>
  26 #include <sys/proc.h>
  27 #include <sys/buf2.h>
  28 #include <sys/thread2.h>
  29 #include <sys/queue.h>
  30
  31 #ifndef MD_NSECT
  32 #define MD_NSECT (10000 * 2)
  33 #endif
  34
  35 MALLOC_DEFINE(M_MD, "MD disk", "Memory Disk");
  36 MALLOC_DEFINE(M_MDSECT, "MD sectors", "Memory Disk Sectors");
  37
  38 static int md_debug;
  39 SYSCTL_INT(_debug, OID_AUTO, mddebug, CTLFLAG_RW, &md_debug, 0, "");
  40
  41 #if defined(MD_ROOT) && defined(MD_ROOT_SIZE)
  42 /* Image gets put here: */
  43 static u_char mfs_root[MD_ROOT_SIZE*1024] = "MFS Filesystem goes here";
  44 static u_char end_mfs_root[] __unused = "MFS Filesystem had better STOP here";
  45 #endif
  46
  47 static int mdrootready;
  48
  49 #define CDEV_MAJOR      95
  50
  51 static d_strategy_t mdstrategy;
  52 static d_strategy_t mdstrategy_preload;
  53 static d_strategy_t mdstrategy_malloc;
  54 static d_open_t mdopen;
  55 static d_close_t mdclose;
  56 static d_ioctl_t mdioctl;
  57
  58 static struct dev_ops md_ops = {
  59         { "md", CDEV_MAJOR, D_DISK | D_CANFREE | D_MEMDISK | D_TRACKCLOSE},
  60         .d_open =       mdopen,
  61         .d_close =      mdclose,
  62         .d_read =       physread,
  63         .d_write =      physwrite,
  64         .d_ioctl =      mdioctl,
  65         .d_strategy =   mdstrategy,
  66 };
  67
  68 struct md_s {
  69         int unit;
  70         struct devstat stats;
  71         struct bio_queue_head bio_queue;
  72         struct disk disk;
  73         cdev_t dev;
  74         int busy;
  75         enum {                  /* Memory disk type */
  76                 MD_MALLOC,
  77                 MD_PRELOAD
  78         } type;
  79         unsigned nsect;
  80
  81         /* MD_MALLOC related fields */
  82         unsigned nsecp;
  83         u_char **secp;
  84
  85         /* MD_PRELOAD related fields */
  86         u_char *pl_ptr;
  87         unsigned pl_len;
  88         TAILQ_ENTRY(md_s) link;
  89 };
  90 TAILQ_HEAD(mdshead, md_s) mdlist = TAILQ_HEAD_INITIALIZER(mdlist);
  91
  92 static int mdunits;
  93 static int refcnt;
  94
  95 static struct md_s *mdcreate(unsigned);
  96 static void mdcreate_malloc(void);
  97 static int mdinit(module_t, int, void *);
  98 static void md_drvinit(void *);
  99 static int md_drvcleanup(void);
 100
 101 static int
 102 mdinit(module_t mod, int cmd, void *arg)
 103 {
 104     int ret = 0;
 105
 106     switch(cmd) {
 107         case MOD_LOAD:
 108                 TAILQ_INIT(&mdlist);
 109                 md_drvinit(NULL);
 110                 break;
 111         case MOD_UNLOAD:
 112                 ret = md_drvcleanup();
 113                 break;
 114         default:
 115                 ret = EINVAL;
 116                 break;
 117     }
 118
 119     return (ret);
 120 }
 121
 122 static int
 123 mdopen(struct dev_open_args *ap)
 124 {
 125         cdev_t dev = ap->a_head.a_dev;
 126         struct md_s *sc;
 127
 128         if (md_debug)
 129                 kprintf("mdopen(%s %x %x)\n",
 130                         devtoname(dev), ap->a_oflags, ap->a_devtype);
 131
 132         sc = dev->si_drv1;
 133         if (sc->unit + 1 == mdunits)
 134                 mdcreate_malloc();
 135
 136         atomic_add_int(&refcnt, 1);
 137         return (0);
 138 }
 139
 140 static int
 141 mdclose(struct dev_close_args *ap)
 142 {
 143         cdev_t dev = ap->a_head.a_dev;
 144         struct md_s *sc;
 145
 146         if (md_debug)
 147                 kprintf("mdclose(%s %x %x)\n",
 148                         devtoname(dev), ap->a_fflag, ap->a_devtype);
 149         sc = dev->si_drv1;
 150         atomic_add_int(&refcnt, -1);
 151
 152         return (0);
 153 }
 154
 155 static int
 156 mdioctl(struct dev_ioctl_args *ap)
 157 {
 158         cdev_t dev = ap->a_head.a_dev;
 159
 160         if (md_debug)
 161                 kprintf("mdioctl(%s %lx %p %x)\n",
 162                         devtoname(dev), ap->a_cmd, ap->a_data, ap->a_fflag);
 163
 164         return (ENOIOCTL);
 165 }
 166
 167 static int
 168 mdstrategy(struct dev_strategy_args *ap)
 169 {
 170         cdev_t dev = ap->a_head.a_dev;
 171         struct bio *bio = ap->a_bio;
 172         struct buf *bp = bio->bio_buf;
 173         struct md_s *sc;
 174
 175         if (md_debug > 1) {
 176                 kprintf("mdstrategy(%p) %s %08x, %lld, %d, %p)\n",
 177                     bp, devtoname(dev), bp->b_flags,
 178                     (long long)bio->bio_offset,
 179                     bp->b_bcount, bp->b_data);
 180         }
 181         bio->bio_driver_info = dev;
 182         sc = dev->si_drv1;
 183         if (sc->type == MD_MALLOC) {
 184                 mdstrategy_malloc(ap);
 185         } else {
 186                 mdstrategy_preload(ap);
 187         }
 188         return(0);
 189 }
 190
 191
 192 static int
 193 mdstrategy_malloc(struct dev_strategy_args *ap)
 194 {
 195         cdev_t dev = ap->a_head.a_dev;
 196         struct bio *bio = ap->a_bio;
 197         struct buf *bp = bio->bio_buf;
 198         unsigned secno, nsec, secval, uc;
 199         u_char *secp, **secpp, *dst;
 200         struct md_s *sc;
 201         int i;
 202
 203         if (md_debug > 1)
 204                 kprintf("mdstrategy_malloc(%p) %s %08xx, %lld, %d, %p)\n",
 205                     bp, devtoname(dev), bp->b_flags,
 206                     (long long)bio->bio_offset,
 207                     bp->b_bcount, bp->b_data);
 208
 209         sc = dev->si_drv1;
 210
 211         crit_enter();
 212
 213         bioqdisksort(&sc->bio_queue, bio);
 214
 215         if (sc->busy) {
 216                 crit_exit();
 217                 return(0);
 218         }
 219
 220         sc->busy++;
 221
 222         while (1) {
 223                 bio = bioq_first(&sc->bio_queue);
 224                 if (bio == NULL) {
 225                         crit_exit();
 226                         break;
 227                 }
 228                 crit_exit();
 229                 bioq_remove(&sc->bio_queue, bio);
 230                 bp = bio->bio_buf;
 231
 232                 devstat_start_transaction(&sc->stats);
 233
 234                 switch (bp->b_cmd) {
 235                 case BUF_CMD_FREEBLKS:
 236                 case BUF_CMD_READ:
 237                 case BUF_CMD_WRITE:
 238                         break;
 239                 default:
 240                         panic("md: bad b_cmd %d", bp->b_cmd);
 241                 }
 242
 243                 nsec = bp->b_bcount >> DEV_BSHIFT;
 244                 secno = (unsigned)(bio->bio_offset >> DEV_BSHIFT);
 245                 dst = bp->b_data;
 246                 while (nsec--) {
 247                         if (secno < sc->nsecp) {
 248                                 secpp = &sc->secp[secno];
 249                                 if ((u_int)(uintptr_t)*secpp > 255) {
 250                                         secp = *secpp;
 251                                         secval = 0;
 252                                 } else {
 253                                         secp = 0;
 254                                         secval = (u_int)(uintptr_t)*secpp;
 255                                 }
 256                         } else {
 257                                 secpp = 0;
 258                                 secp = 0;
 259                                 secval = 0;
 260                         }
 261                         if (md_debug > 2)
 262                                 kprintf("%08x %p %p %d\n", bp->b_flags, secpp, secp, secval);
 263
 264                         switch (bp->b_cmd) {
 265                         case BUF_CMD_FREEBLKS:
 266                                 if (secpp) {
 267                                         if (secp)
 268                                                 FREE(secp, M_MDSECT);
 269                                         *secpp = 0;
 270                                 }
 271                                 break;
 272                         case BUF_CMD_READ:
 273                                 if (secp) {
 274                                         bcopy(secp, dst, DEV_BSIZE);
 275                                 } else if (secval) {
 276                                         for (i = 0; i < DEV_BSIZE; i++)
 277                                                 dst[i] = secval;
 278                                 } else {
 279                                         bzero(dst, DEV_BSIZE);
 280                                 }
 281                                 break;
 282                         case BUF_CMD_WRITE:
 283                                 uc = dst[0];
 284                                 for (i = 1; i < DEV_BSIZE; i++)
 285                                         if (dst[i] != uc)
 286                                                 break;
 287                                 if (i == DEV_BSIZE && !uc) {
 288                                         if (secp)
 289                                                 FREE(secp, M_MDSECT);
 290                                         if (secpp)
 291                                                 *secpp = (u_char *)(uintptr_t)uc;
 292                                 } else {
 293                                         if (!secpp) {
 294                                                 MALLOC(secpp, u_char **, (secno + nsec + 1) * sizeof(u_char *), M_MD, M_WAITOK | M_ZERO);
 295                                                 bcopy(sc->secp, secpp, sc->nsecp * sizeof(u_char *));
 296                                                 FREE(sc->secp, M_MD);
 297                                                 sc->secp = secpp;
 298                                                 sc->nsecp = secno + nsec + 1;
 299                                                 secpp = &sc->secp[secno];
 300                                         }
 301                                         if (i == DEV_BSIZE) {
 302                                                 if (secp)
 303                                                         FREE(secp, M_MDSECT);
 304                                                 *secpp = (u_char *)(uintptr_t)uc;
 305                                         } else {
 306                                                 if (!secp)
 307                                                         MALLOC(secp, u_char *, DEV_BSIZE, M_MDSECT, M_WAITOK);
 308                                                 bcopy(dst, secp, DEV_BSIZE);
 309
 310                                                 *secpp = secp;
 311                                         }
 312                                 }
 313                                 break;
 314                         default:
 315                                 panic("md: bad b_cmd %d", bp->b_cmd);
 316
 317                         }
 318                         secno++;
 319                         dst += DEV_BSIZE;
 320                 }
 321                 bp->b_resid = 0;
 322                 devstat_end_transaction_buf(&sc->stats, bp);
 323                 biodone(bio);
 324                 crit_enter();
 325         }
 326         sc->busy = 0;
 327         return(0);
 328 }
 329
 330
 331 static int
 332 mdstrategy_preload(struct dev_strategy_args *ap)
 333 {
 334         cdev_t dev = ap->a_head.a_dev;
 335         struct bio *bio = ap->a_bio;
 336         struct buf *bp = bio->bio_buf;
 337         struct md_s *sc;
 338
 339         if (md_debug > 1)
 340                 kprintf("mdstrategy_preload(%p) %s %08x, %lld, %d, %p)\n",
 341                     bp, devtoname(dev), bp->b_flags,
 342                     (long long)bio->bio_offset,
 343                     bp->b_bcount, bp->b_data);
 344
 345         sc = dev->si_drv1;
 346
 347         crit_enter();
 348
 349         bioqdisksort(&sc->bio_queue, bio);
 350
 351         if (sc->busy) {
 352                 crit_exit();
 353                 return(0);
 354         }
 355
 356         sc->busy++;
 357
 358         while (1) {
 359                 bio = bioq_first(&sc->bio_queue);
 360                 if (bio)
 361                         bioq_remove(&sc->bio_queue, bio);
 362                 crit_exit();
 363                 if (bio == NULL)
 364                         break;
 365
 366                 devstat_start_transaction(&sc->stats);
 367
 368                 switch (bp->b_cmd) {
 369                 case BUF_CMD_FREEBLKS:
 370                         break;
 371                 case BUF_CMD_READ:
 372                         bcopy(sc->pl_ptr + bio->bio_offset,
 373                                bp->b_data, bp->b_bcount);
 374                         break;
 375                 case BUF_CMD_WRITE:
 376                         bcopy(bp->b_data, sc->pl_ptr + bio->bio_offset,
 377                               bp->b_bcount);
 378                         break;
 379                 default:
 380                         panic("md: bad cmd %d\n", bp->b_cmd);
 381                 }
 382                 bp->b_resid = 0;
 383                 devstat_end_transaction_buf(&sc->stats, bp);
 384                 biodone(bio);
 385                 crit_enter();
 386         }
 387         sc->busy = 0;
 388         return(0);
 389 }
 390
 391 static struct md_s *
 392 mdcreate(unsigned length)
 393 {
 394         struct md_s *sc;
 395         struct disk_info info;
 396
 397         MALLOC(sc, struct md_s *,sizeof(*sc), M_MD, M_WAITOK | M_ZERO);
 398         sc->unit = mdunits++;
 399         bioq_init(&sc->bio_queue);
 400         devstat_add_entry(&sc->stats, "md", sc->unit, DEV_BSIZE,
 401                 DEVSTAT_NO_ORDERED_TAGS,
 402                 DEVSTAT_TYPE_DIRECT | DEVSTAT_TYPE_IF_OTHER,
 403                 DEVSTAT_PRIORITY_OTHER);
 404         sc->dev = disk_create(sc->unit, &sc->disk, &md_ops);
 405         sc->dev->si_drv1 = sc;
 406         sc->dev->si_iosize_max = DFLTPHYS;
 407
 408         bzero(&info, sizeof(info));
 409         info.d_media_blksize = DEV_BSIZE;       /* mandatory */
 410         info.d_media_blocks = length / DEV_BSIZE;
 411
 412         info.d_secpertrack = 1024;              /* optional */
 413         info.d_nheads = 1;
 414         info.d_secpercyl = info.d_secpertrack * info.d_nheads;
 415         info.d_ncylinders = (u_int)(info.d_media_blocks / info.d_secpercyl);
 416         disk_setdiskinfo(&sc->disk, &info);
 417         TAILQ_INSERT_HEAD(&mdlist, sc, link);
 418
 419         return (sc);
 420 }
 421
 422
 423 static void
 424 mdcreate_preload(u_char *image, unsigned length)
 425 {
 426         struct md_s *sc;
 427
 428         sc = mdcreate(length);
 429         sc->type = MD_PRELOAD;
 430         sc->nsect = length / DEV_BSIZE;
 431         sc->pl_ptr = image;
 432         sc->pl_len = length;
 433
 434         if (sc->unit == 0)
 435                 mdrootready = 1;
 436 }
 437
 438 static void
 439 mdcreate_malloc(void)
 440 {
 441         struct md_s *sc;
 442
 443         sc = mdcreate(MD_NSECT*DEV_BSIZE);
 444         sc->type = MD_MALLOC;
 445
 446         sc->nsect = MD_NSECT;   /* for now */
 447         MALLOC(sc->secp, u_char **, sizeof(u_char *), M_MD, M_WAITOK | M_ZERO);
 448         sc->nsecp = 1;
 449         kprintf("md%d: Malloc disk\n", sc->unit);
 450 }
 451
 452 static int
 453 md_drvcleanup(void)
 454 {
 455
 456         int secno;
 457         struct md_s *sc, *sc_temp;
 458
 459         if (atomic_fetchadd_int(&refcnt, 0) != 0)
 460                 return EBUSY;
 461
 462         /*
 463          * Go through all the md devices, freeing up all the
 464          * memory allocated for sectors, and the md_s struct
 465          * itself.
 466          */
 467         TAILQ_FOREACH_MUTABLE(sc, &mdlist, link, sc_temp) {
 468                 for (secno = 0; secno < sc->nsecp; secno++) {
 469                         if ((u_int)(uintptr_t)sc->secp[secno] > 255)
 470                                 FREE(sc->secp[secno], M_MDSECT);
 471                 }
 472
 473                 if (sc->dev != NULL)
 474                         disk_destroy(&sc->disk);
 475
 476                 devstat_remove_entry(&sc->stats);
 477                 TAILQ_REMOVE(&mdlist, sc, link);
 478
 479                 FREE(sc->secp, M_MD);
 480                 FREE(sc, M_MD);
 481         }
 482
 483         return 0;
 484
 485 }
 486
 487 static void
 488 md_drvinit(void *unused)
 489 {
 490
 491         caddr_t mod;
 492         caddr_t c;
 493         u_char *ptr, *name, *type;
 494         unsigned len;
 495
 496 #ifdef MD_ROOT_SIZE
 497         mdcreate_preload(mfs_root, MD_ROOT_SIZE*1024);
 498 #endif
 499         mod = NULL;
 500         while ((mod = preload_search_next_name(mod)) != NULL) {
 501                 name = (char *)preload_search_info(mod, MODINFO_NAME);
 502                 type = (char *)preload_search_info(mod, MODINFO_TYPE);
 503                 if (name == NULL)
 504                         continue;
 505                 if (type == NULL)
 506                         continue;
 507                 if (strcmp(type, "md_image") && strcmp(type, "mfs_root"))
 508                         continue;
 509                 c = preload_search_info(mod, MODINFO_ADDR);
 510                 ptr = *(u_char **)c;
 511                 c = preload_search_info(mod, MODINFO_SIZE);
 512                 len = *(unsigned *)c;
 513                 kprintf("md%d: Preloaded image <%s> %d bytes at %p\n",
 514                    mdunits, name, len, ptr);
 515                 mdcreate_preload(ptr, len);
 516         }
 517         mdcreate_malloc();
 518 }
 519
 520 DEV_MODULE(md, mdinit, NULL);
 521
 522 #ifdef MD_ROOT
 523 static void
 524 md_takeroot(void *junk)
 525 {
 526         if (mdrootready)
 527                 rootdevnames[0] = "ufs:/dev/md0s0";
 528 }
 529
 530 SYSINIT(md_root, SI_SUB_MOUNT_ROOT, SI_ORDER_FIRST, md_takeroot, NULL);
 531 #endif