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  *
  11  */
  12
  13 #include "opt_md.h"             /* We have adopted some tasks from MFS */
  14
  15 #include <sys/param.h>
  16 #include <sys/systm.h>
  17 #include <sys/buf.h>
  18 #include <sys/conf.h>
  19 #include <sys/devicestat.h>
  20 #include <sys/disk.h>
  21 #include <sys/kernel.h>
  22 #include <sys/malloc.h>
  23 #include <sys/sysctl.h>
  24 #include <sys/linker.h>
  25 #include <sys/proc.h>
  26 #include <sys/buf2.h>
  27 #include <sys/thread2.h>
  28 #include <sys/queue.h>
  29 #include <sys/udev.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     "Enable debug output for memory disk devices");
  41
  42 #if defined(MD_ROOT) && defined(MD_ROOT_SIZE)
  43 /* Image gets put here: */
  44 static u_char mfs_root[MD_ROOT_SIZE*1024] = "MFS Filesystem goes here";
  45 static u_char end_mfs_root[] __unused = "MFS Filesystem had better STOP here";
  46 #endif
  47
  48 static int mdrootready;
  49
  50 static d_strategy_t mdstrategy;
  51 static d_strategy_t mdstrategy_preload;
  52 static d_strategy_t mdstrategy_malloc;
  53 static d_open_t mdopen;
  54 static d_close_t mdclose;
  55 static d_ioctl_t mdioctl;
  56
  57 static struct dev_ops md_ops = {
  58         { "md", 0, D_DISK | D_CANFREE | D_MEMDISK | D_TRACKCLOSE},
  59         .d_open =       mdopen,
  60         .d_close =      mdclose,
  61         .d_read =       physread,
  62         .d_write =      physwrite,
  63         .d_ioctl =      mdioctl,
  64         .d_strategy =   mdstrategy,
  65 };
  66
  67 struct md_s {
  68         int unit;
  69         struct devstat stats;
  70         struct bio_queue_head bio_queue;
  71         struct disk disk;
  72         cdev_t dev;
  73         int busy;
  74         enum {                  /* Memory disk type */
  75                 MD_MALLOC,
  76                 MD_PRELOAD
  77         } type;
  78         unsigned nsect;
  79
  80         /* MD_MALLOC related fields */
  81         unsigned nsecp;
  82         u_char **secp;
  83
  84         /* MD_PRELOAD related fields */
  85         u_char *pl_ptr;
  86         unsigned pl_len;
  87         TAILQ_ENTRY(md_s) link;
  88 };
  89 TAILQ_HEAD(mdshead, md_s) mdlist = TAILQ_HEAD_INITIALIZER(mdlist);
  90
  91 static int mdunits;
  92 static int refcnt;
  93
  94 static struct md_s *mdcreate(unsigned);
  95 static void mdcreate_malloc(void);
  96 static int mdinit(module_t, int, void *);
  97 static void md_drvinit(void *);
  98 static int md_drvcleanup(void);
  99
 100 static int
 101 mdinit(module_t mod, int cmd, void *arg)
 102 {
 103     int ret = 0;
 104
 105     switch(cmd) {
 106         case MOD_LOAD:
 107                 TAILQ_INIT(&mdlist);
 108                 md_drvinit(NULL);
 109                 break;
 110         case MOD_UNLOAD:
 111                 ret = md_drvcleanup();
 112                 break;
 113         default:
 114                 ret = EINVAL;
 115                 break;
 116     }
 117
 118     return (ret);
 119 }
 120
 121 static int
 122 mdopen(struct dev_open_args *ap)
 123 {
 124         cdev_t dev = ap->a_head.a_dev;
 125         struct md_s *sc;
 126
 127         if (md_debug)
 128                 kprintf("mdopen(%s %x %x)\n",
 129                         devtoname(dev), ap->a_oflags, ap->a_devtype);
 130
 131         sc = dev->si_drv1;
 132         if (sc->unit + 1 == mdunits)
 133                 mdcreate_malloc();
 134
 135         atomic_add_int(&refcnt, 1);
 136         return (0);
 137 }
 138
 139 static int
 140 mdclose(struct dev_close_args *ap)
 141 {
 142         cdev_t dev = ap->a_head.a_dev;
 143
 144         if (md_debug)
 145                 kprintf("mdclose(%s %x %x)\n",
 146                         devtoname(dev), ap->a_fflag, ap->a_devtype);
 147         atomic_add_int(&refcnt, -1);
 148
 149         return (0);
 150 }
 151
 152 static int
 153 mdioctl(struct dev_ioctl_args *ap)
 154 {
 155         cdev_t dev = ap->a_head.a_dev;
 156
 157         if (md_debug)
 158                 kprintf("mdioctl(%s %lx %p %x)\n",
 159                         devtoname(dev), ap->a_cmd, ap->a_data, ap->a_fflag);
 160
 161         return (ENOIOCTL);
 162 }
 163
 164 static int
 165 mdstrategy(struct dev_strategy_args *ap)
 166 {
 167         cdev_t dev = ap->a_head.a_dev;
 168         struct bio *bio = ap->a_bio;
 169         struct buf *bp = bio->bio_buf;
 170         struct md_s *sc;
 171
 172         if (md_debug > 1) {
 173                 kprintf("mdstrategy(%p) %s %08x, %lld, %d, %p)\n",
 174                     bp, devtoname(dev), bp->b_flags,
 175                     (long long)bio->bio_offset,
 176                     bp->b_bcount, bp->b_data);
 177         }
 178         bio->bio_driver_info = dev;
 179         sc = dev->si_drv1;
 180         if (sc->type == MD_MALLOC) {
 181                 mdstrategy_malloc(ap);
 182         } else {
 183                 mdstrategy_preload(ap);
 184         }
 185         return(0);
 186 }
 187
 188
 189 static int
 190 mdstrategy_malloc(struct dev_strategy_args *ap)
 191 {
 192         cdev_t dev = ap->a_head.a_dev;
 193         struct bio *bio = ap->a_bio;
 194         struct buf *bp = bio->bio_buf;
 195         unsigned secno, nsec, secval, uc;
 196         u_char *secp, **secpp, *dst;
 197         struct md_s *sc;
 198         int i;
 199
 200         if (md_debug > 1)
 201                 kprintf("mdstrategy_malloc(%p) %s %08xx, %lld, %d, %p)\n",
 202                     bp, devtoname(dev), bp->b_flags,
 203                     (long long)bio->bio_offset,
 204                     bp->b_bcount, bp->b_data);
 205
 206         sc = dev->si_drv1;
 207
 208         crit_enter();
 209
 210         bioqdisksort(&sc->bio_queue, bio);
 211
 212         if (sc->busy) {
 213                 crit_exit();
 214                 return(0);
 215         }
 216
 217         sc->busy++;
 218
 219         while (1) {
 220                 bio = bioq_first(&sc->bio_queue);
 221                 if (bio == NULL) {
 222                         crit_exit();
 223                         break;
 224                 }
 225                 crit_exit();
 226                 bioq_remove(&sc->bio_queue, bio);
 227                 bp = bio->bio_buf;
 228
 229                 devstat_start_transaction(&sc->stats);
 230
 231                 switch (bp->b_cmd) {
 232                 case BUF_CMD_FREEBLKS:
 233                 case BUF_CMD_READ:
 234                 case BUF_CMD_WRITE:
 235                         break;
 236                 default:
 237                         panic("md: bad b_cmd %d", bp->b_cmd);
 238                 }
 239
 240                 nsec = bp->b_bcount >> DEV_BSHIFT;
 241                 secno = (unsigned)(bio->bio_offset >> DEV_BSHIFT);
 242                 dst = bp->b_data;
 243                 while (nsec--) {
 244                         if (secno < sc->nsecp) {
 245                                 secpp = &sc->secp[secno];
 246                                 if ((u_int)(uintptr_t)*secpp > 255) {
 247                                         secp = *secpp;
 248                                         secval = 0;
 249                                 } else {
 250                                         secp = NULL;
 251                                         secval = (u_int)(uintptr_t)*secpp;
 252                                 }
 253                         } else {
 254                                 secpp = NULL;
 255                                 secp = NULL;
 256                                 secval = 0;
 257                         }
 258                         if (md_debug > 2)
 259                                 kprintf("%08x %p %p %d\n", bp->b_flags, secpp, secp, secval);
 260
 261                         switch (bp->b_cmd) {
 262                         case BUF_CMD_FREEBLKS:
 263                                 if (secpp) {
 264                                         if (secp)
 265                                                 kfree(secp, M_MDSECT);
 266                                         *secpp = NULL;
 267                                 }
 268                                 break;
 269                         case BUF_CMD_READ:
 270                                 if (secp) {
 271                                         bcopy(secp, dst, DEV_BSIZE);
 272                                 } else if (secval) {
 273                                         for (i = 0; i < DEV_BSIZE; i++)
 274                                                 dst[i] = secval;
 275                                 } else {
 276                                         bzero(dst, DEV_BSIZE);
 277                                 }
 278                                 break;
 279                         case BUF_CMD_WRITE:
 280                                 uc = dst[0];
 281                                 for (i = 1; i < DEV_BSIZE; i++)
 282                                         if (dst[i] != uc)
 283                                                 break;
 284                                 if (i == DEV_BSIZE && !uc) {
 285                                         if (secp)
 286                                                 kfree(secp, M_MDSECT);
 287                                         if (secpp)
 288                                                 *secpp = (u_char *)(uintptr_t)uc;
 289                                 } else {
 290                                         if (!secpp) {
 291                                                 secpp = kmalloc((secno + nsec + 1) * sizeof(u_char *),
 292                                                                 M_MD,
 293                                                                 M_WAITOK | M_ZERO);
 294                                                 bcopy(sc->secp, secpp, sc->nsecp * sizeof(u_char *));
 295                                                 kfree(sc->secp, M_MD);
 296                                                 sc->secp = secpp;
 297                                                 sc->nsecp = secno + nsec + 1;
 298                                                 secpp = &sc->secp[secno];
 299                                         }
 300                                         if (i == DEV_BSIZE) {
 301                                                 if (secp)
 302                                                         kfree(secp, M_MDSECT);
 303                                                 *secpp = (u_char *)(uintptr_t)uc;
 304                                         } else {
 305                                                 if (!secp)
 306                                                         secp = kmalloc(DEV_BSIZE,
 307                                                                        M_MDSECT,
 308                                                                        M_WAITOK);
 309                                                 bcopy(dst, secp, DEV_BSIZE);
 310
 311                                                 *secpp = secp;
 312                                         }
 313                                 }
 314                                 break;
 315                         default:
 316                                 panic("md: bad b_cmd %d", bp->b_cmd);
 317
 318                         }
 319                         secno++;
 320                         dst += DEV_BSIZE;
 321                 }
 322                 bp->b_resid = 0;
 323                 devstat_end_transaction_buf(&sc->stats, bp);
 324                 biodone(bio);
 325                 crit_enter();
 326         }
 327         sc->busy = 0;
 328         return(0);
 329 }
 330
 331
 332 static int
 333 mdstrategy_preload(struct dev_strategy_args *ap)
 334 {
 335         cdev_t dev = ap->a_head.a_dev;
 336         struct bio *bio = ap->a_bio;
 337         struct buf *bp = bio->bio_buf;
 338         struct md_s *sc;
 339
 340         if (md_debug > 1)
 341                 kprintf("mdstrategy_preload(%p) %s %08x, %lld, %d, %p)\n",
 342                     bp, devtoname(dev), bp->b_flags,
 343                     (long long)bio->bio_offset,
 344                     bp->b_bcount, bp->b_data);
 345
 346         sc = dev->si_drv1;
 347
 348         crit_enter();
 349
 350         bioqdisksort(&sc->bio_queue, bio);
 351
 352         if (sc->busy) {
 353                 crit_exit();
 354                 return(0);
 355         }
 356
 357         sc->busy++;
 358
 359         while (1) {
 360                 bio = bioq_takefirst(&sc->bio_queue);
 361                 crit_exit();
 362                 if (bio == NULL)
 363                         break;
 364
 365                 devstat_start_transaction(&sc->stats);
 366
 367                 switch (bp->b_cmd) {
 368                 case BUF_CMD_FREEBLKS:
 369                         break;
 370                 case BUF_CMD_READ:
 371                         bcopy(sc->pl_ptr + bio->bio_offset,
 372                                bp->b_data, bp->b_bcount);
 373                         break;
 374                 case BUF_CMD_WRITE:
 375                         bcopy(bp->b_data, sc->pl_ptr + bio->bio_offset,
 376                               bp->b_bcount);
 377                         break;
 378                 default:
 379                         panic("md: bad cmd %d", bp->b_cmd);
 380                 }
 381                 bp->b_resid = 0;
 382                 devstat_end_transaction_buf(&sc->stats, bp);
 383                 biodone(bio);
 384                 crit_enter();
 385         }
 386         sc->busy = 0;
 387         return(0);
 388 }
 389
 390 static struct md_s *
 391 mdcreate(unsigned length)
 392 {
 393         struct md_s *sc;
 394         struct disk_info info;
 395
 396         sc = kmalloc(sizeof(*sc), M_MD, M_WAITOK | M_ZERO);
 397         sc->unit = mdunits++;
 398         bioq_init(&sc->bio_queue);
 399         devstat_add_entry(&sc->stats, "md", sc->unit, DEV_BSIZE,
 400                 DEVSTAT_NO_ORDERED_TAGS,
 401                 DEVSTAT_TYPE_DIRECT | DEVSTAT_TYPE_IF_OTHER,
 402                 DEVSTAT_PRIORITY_OTHER);
 403         sc->dev = disk_create(sc->unit, &sc->disk, &md_ops);
 404         sc->dev->si_drv1 = sc;
 405         sc->dev->si_iosize_max = MAXPHYS;
 406         disk_setdisktype(&sc->disk, "memory");
 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         sc->secp = kmalloc(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                                 kfree(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                 kfree(sc->secp, M_MD);
 480                 kfree(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