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
  30 #ifndef MD_NSECT
  31 #define MD_NSECT (10000 * 2)
  32 #endif
  33
  34 MALLOC_DEFINE(M_MD, "MD disk", "Memory Disk");
  35 MALLOC_DEFINE(M_MDSECT, "MD sectors", "Memory Disk Sectors");
  36
  37 static int md_debug;
  38 SYSCTL_INT(_debug, OID_AUTO, mddebug, CTLFLAG_RW, &md_debug, 0, "");
  39
  40 #if defined(MD_ROOT) && defined(MD_ROOT_SIZE)
  41 /* Image gets put here: */
  42 static u_char mfs_root[MD_ROOT_SIZE*1024] = "MFS Filesystem goes here";
  43 static u_char end_mfs_root[] __unused = "MFS Filesystem had better STOP here";
  44 #endif
  45
  46 static int mdrootready;
  47
  48 static void mdcreate_malloc(void);
  49
  50 #define CDEV_MAJOR      95
  51
  52 static d_strategy_t mdstrategy;
  53 static d_strategy_t mdstrategy_preload;
  54 static d_strategy_t mdstrategy_malloc;
  55 static d_open_t mdopen;
  56 static d_ioctl_t mdioctl;
  57
  58 static struct dev_ops md_ops = {
  59         { "md", CDEV_MAJOR, D_DISK | D_CANFREE | D_MEMDISK },
  60         .d_open =       mdopen,
  61         .d_close =      nullclose,
  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 {MD_MALLOC, MD_PRELOAD} type;
  76         unsigned nsect;
  77
  78         /* MD_MALLOC related fields */
  79         unsigned nsecp;
  80         u_char **secp;
  81
  82         /* MD_PRELOAD related fields */
  83         u_char *pl_ptr;
  84         unsigned pl_len;
  85 };
  86
  87 static int mdunits;
  88
  89 static int
  90 mdopen(struct dev_open_args *ap)
  91 {
  92         cdev_t dev = ap->a_head.a_dev;
  93         struct md_s *sc;
  94 #if 0
  95         struct disk_info info;
  96 #endif
  97
  98         if (md_debug)
  99                 kprintf("mdopen(%s %x %x)\n",
 100                         devtoname(dev), ap->a_oflags, ap->a_devtype);
 101
 102         sc = dev->si_drv1;
 103         if (sc->unit + 1 == mdunits)
 104                 mdcreate_malloc();
 105 #if 0
 106         bzero(&info, sizeof(info));
 107         info.d_media_blksize = DEV_BSIZE;       /* mandatory */
 108         info.d_media_blocks = sc->nsect;
 109
 110         info.d_secpertrack = 1024;              /* optional */
 111         info.d_nheads = 1;
 112         info.d_secpercyl = info.d_secpertrack * info.d_nheads;
 113         info.d_ncylinders = (u_int)(info.d_media_blocks / info.d_secpercyl);
 114         disk_setdiskinfo(&sc->disk, &info);
 115 #endif
 116         return (0);
 117 }
 118
 119 static int
 120 mdioctl(struct dev_ioctl_args *ap)
 121 {
 122         cdev_t dev = ap->a_head.a_dev;
 123
 124         if (md_debug)
 125                 kprintf("mdioctl(%s %lx %p %x)\n",
 126                         devtoname(dev), ap->a_cmd, ap->a_data, ap->a_fflag);
 127
 128         return (ENOIOCTL);
 129 }
 130
 131 static int
 132 mdstrategy(struct dev_strategy_args *ap)
 133 {
 134         cdev_t dev = ap->a_head.a_dev;
 135         struct bio *bio = ap->a_bio;
 136         struct buf *bp = bio->bio_buf;
 137         struct md_s *sc;
 138
 139         if (md_debug > 1) {
 140                 kprintf("mdstrategy(%p) %s %08x, %lld, %d, %p)\n",
 141                     bp, devtoname(dev), bp->b_flags,
 142                     (long long)bio->bio_offset,
 143                     bp->b_bcount, bp->b_data);
 144         }
 145         bio->bio_driver_info = dev;
 146         sc = dev->si_drv1;
 147         if (sc->type == MD_MALLOC) {
 148                 mdstrategy_malloc(ap);
 149         } else {
 150                 mdstrategy_preload(ap);
 151         }
 152         return(0);
 153 }
 154
 155
 156 static int
 157 mdstrategy_malloc(struct dev_strategy_args *ap)
 158 {
 159         cdev_t dev = ap->a_head.a_dev;
 160         struct bio *bio = ap->a_bio;
 161         struct buf *bp = bio->bio_buf;
 162         unsigned secno, nsec, secval, uc;
 163         u_char *secp, **secpp, *dst;
 164         struct md_s *sc;
 165         int i;
 166
 167         if (md_debug > 1)
 168                 kprintf("mdstrategy_malloc(%p) %s %08xx, %lld, %d, %p)\n",
 169                     bp, devtoname(dev), bp->b_flags,
 170                     (long long)bio->bio_offset,
 171                     bp->b_bcount, bp->b_data);
 172
 173         sc = dev->si_drv1;
 174
 175         crit_enter();
 176
 177         bioqdisksort(&sc->bio_queue, bio);
 178
 179         if (sc->busy) {
 180                 crit_exit();
 181                 return(0);
 182         }
 183
 184         sc->busy++;
 185
 186         while (1) {
 187                 bio = bioq_first(&sc->bio_queue);
 188                 if (bio == NULL) {
 189                         crit_exit();
 190                         break;
 191                 }
 192                 crit_exit();
 193                 bioq_remove(&sc->bio_queue, bio);
 194                 bp = bio->bio_buf;
 195
 196                 devstat_start_transaction(&sc->stats);
 197
 198                 switch (bp->b_cmd) {
 199                 case BUF_CMD_FREEBLKS:
 200                 case BUF_CMD_READ:
 201                 case BUF_CMD_WRITE:
 202                         break;
 203                 default:
 204                         panic("md: bad b_cmd %d", bp->b_cmd);
 205                 }
 206
 207                 nsec = bp->b_bcount >> DEV_BSHIFT;
 208                 secno = (unsigned)(bio->bio_offset >> DEV_BSHIFT);
 209                 dst = bp->b_data;
 210                 while (nsec--) {
 211                         if (secno < sc->nsecp) {
 212                                 secpp = &sc->secp[secno];
 213                                 if ((u_int)(uintptr_t)*secpp > 255) {
 214                                         secp = *secpp;
 215                                         secval = 0;
 216                                 } else {
 217                                         secp = 0;
 218                                         secval = (u_int)(uintptr_t)*secpp;
 219                                 }
 220                         } else {
 221                                 secpp = 0;
 222                                 secp = 0;
 223                                 secval = 0;
 224                         }
 225                         if (md_debug > 2)
 226                                 kprintf("%08x %p %p %d\n", bp->b_flags, secpp, secp, secval);
 227
 228                         switch (bp->b_cmd) {
 229                         case BUF_CMD_FREEBLKS:
 230                                 if (secpp) {
 231                                         if (secp)
 232                                                 FREE(secp, M_MDSECT);
 233                                         *secpp = 0;
 234                                 }
 235                                 break;
 236                         case BUF_CMD_READ:
 237                                 if (secp) {
 238                                         bcopy(secp, dst, DEV_BSIZE);
 239                                 } else if (secval) {
 240                                         for (i = 0; i < DEV_BSIZE; i++)
 241                                                 dst[i] = secval;
 242                                 } else {
 243                                         bzero(dst, DEV_BSIZE);
 244                                 }
 245                                 break;
 246                         case BUF_CMD_WRITE:
 247                                 uc = dst[0];
 248                                 for (i = 1; i < DEV_BSIZE; i++)
 249                                         if (dst[i] != uc)
 250                                                 break;
 251                                 if (i == DEV_BSIZE && !uc) {
 252                                         if (secp)
 253                                                 FREE(secp, M_MDSECT);
 254                                         if (secpp)
 255                                                 *secpp = (u_char *)(uintptr_t)uc;
 256                                 } else {
 257                                         if (!secpp) {
 258                                                 MALLOC(secpp, u_char **, (secno + nsec + 1) * sizeof(u_char *), M_MD, M_WAITOK | M_ZERO);
 259                                                 bcopy(sc->secp, secpp, sc->nsecp * sizeof(u_char *));
 260                                                 FREE(sc->secp, M_MD);
 261                                                 sc->secp = secpp;
 262                                                 sc->nsecp = secno + nsec + 1;
 263                                                 secpp = &sc->secp[secno];
 264                                         }
 265                                         if (i == DEV_BSIZE) {
 266                                                 if (secp)
 267                                                         FREE(secp, M_MDSECT);
 268                                                 *secpp = (u_char *)(uintptr_t)uc;
 269                                         } else {
 270                                                 if (!secp)
 271                                                         MALLOC(secp, u_char *, DEV_BSIZE, M_MDSECT, M_WAITOK);
 272                                                 bcopy(dst, secp, DEV_BSIZE);
 273
 274                                                 *secpp = secp;
 275                                         }
 276                                 }
 277                                 break;
 278                         default:
 279                                 panic("md: bad b_cmd %d", bp->b_cmd);
 280
 281                         }
 282                         secno++;
 283                         dst += DEV_BSIZE;
 284                 }
 285                 bp->b_resid = 0;
 286                 devstat_end_transaction_buf(&sc->stats, bp);
 287                 biodone(bio);
 288                 crit_enter();
 289         }
 290         sc->busy = 0;
 291         return(0);
 292 }
 293
 294
 295 static int
 296 mdstrategy_preload(struct dev_strategy_args *ap)
 297 {
 298         cdev_t dev = ap->a_head.a_dev;
 299         struct bio *bio = ap->a_bio;
 300         struct buf *bp = bio->bio_buf;
 301         struct md_s *sc;
 302
 303         if (md_debug > 1)
 304                 kprintf("mdstrategy_preload(%p) %s %08x, %lld, %d, %p)\n",
 305                     bp, devtoname(dev), bp->b_flags,
 306                     (long long)bio->bio_offset,
 307                     bp->b_bcount, bp->b_data);
 308
 309         sc = dev->si_drv1;
 310
 311         crit_enter();
 312
 313         bioqdisksort(&sc->bio_queue, bio);
 314
 315         if (sc->busy) {
 316                 crit_exit();
 317                 return(0);
 318         }
 319
 320         sc->busy++;
 321
 322         while (1) {
 323                 bio = bioq_first(&sc->bio_queue);
 324                 if (bio)
 325                         bioq_remove(&sc->bio_queue, bio);
 326                 crit_exit();
 327                 if (bio == NULL)
 328                         break;
 329
 330                 devstat_start_transaction(&sc->stats);
 331
 332                 switch (bp->b_cmd) {
 333                 case BUF_CMD_FREEBLKS:
 334                         break;
 335                 case BUF_CMD_READ:
 336                         bcopy(sc->pl_ptr + bio->bio_offset,
 337                                bp->b_data, bp->b_bcount);
 338                         break;
 339                 case BUF_CMD_WRITE:
 340                         bcopy(bp->b_data, sc->pl_ptr + bio->bio_offset,
 341                               bp->b_bcount);
 342                         break;
 343                 default:
 344                         panic("md: bad cmd %d\n", bp->b_cmd);
 345                 }
 346                 bp->b_resid = 0;
 347                 devstat_end_transaction_buf(&sc->stats, bp);
 348                 biodone(bio);
 349                 crit_enter();
 350         }
 351         sc->busy = 0;
 352         return(0);
 353 }
 354
 355 static struct md_s *
 356 mdcreate(unsigned length)
 357 {
 358         struct md_s *sc;
 359         struct disk_info info;
 360
 361         MALLOC(sc, struct md_s *,sizeof(*sc), M_MD, M_WAITOK | M_ZERO);
 362         sc->unit = mdunits++;
 363         bioq_init(&sc->bio_queue);
 364         devstat_add_entry(&sc->stats, "md", sc->unit, DEV_BSIZE,
 365                 DEVSTAT_NO_ORDERED_TAGS,
 366                 DEVSTAT_TYPE_DIRECT | DEVSTAT_TYPE_IF_OTHER,
 367                 DEVSTAT_PRIORITY_OTHER);
 368         sc->dev = disk_create(sc->unit, &sc->disk, &md_ops);
 369         sc->dev->si_drv1 = sc;
 370         sc->dev->si_iosize_max = DFLTPHYS;
 371
 372         bzero(&info, sizeof(info));
 373         info.d_media_blksize = DEV_BSIZE;       /* mandatory */
 374         info.d_media_blocks = length / DEV_BSIZE;
 375
 376         info.d_secpertrack = 1024;              /* optional */
 377         info.d_nheads = 1;
 378         info.d_secpercyl = info.d_secpertrack * info.d_nheads;
 379         info.d_ncylinders = (u_int)(info.d_media_blocks / info.d_secpercyl);
 380         disk_setdiskinfo(&sc->disk, &info);
 381
 382         return (sc);
 383 }
 384
 385 static void
 386 mdcreate_preload(u_char *image, unsigned length)
 387 {
 388         struct md_s *sc;
 389
 390         sc = mdcreate(length);
 391         sc->type = MD_PRELOAD;
 392         sc->nsect = length / DEV_BSIZE;
 393         sc->pl_ptr = image;
 394         sc->pl_len = length;
 395
 396         if (sc->unit == 0)
 397                 mdrootready = 1;
 398 }
 399
 400 static void
 401 mdcreate_malloc(void)
 402 {
 403         struct md_s *sc;
 404
 405         sc = mdcreate(0);
 406         sc->type = MD_MALLOC;
 407
 408         sc->nsect = MD_NSECT;   /* for now */
 409         MALLOC(sc->secp, u_char **, sizeof(u_char *), M_MD, M_WAITOK | M_ZERO);
 410         sc->nsecp = 1;
 411         kprintf("md%d: Malloc disk\n", sc->unit);
 412 }
 413
 414 static void
 415 md_drvinit(void *unused)
 416 {
 417
 418         caddr_t mod;
 419         caddr_t c;
 420         u_char *ptr, *name, *type;
 421         unsigned len;
 422
 423 #ifdef MD_ROOT_SIZE
 424         mdcreate_preload(mfs_root, MD_ROOT_SIZE*1024);
 425 #endif
 426         mod = NULL;
 427         while ((mod = preload_search_next_name(mod)) != NULL) {
 428                 name = (char *)preload_search_info(mod, MODINFO_NAME);
 429                 type = (char *)preload_search_info(mod, MODINFO_TYPE);
 430                 if (name == NULL)
 431                         continue;
 432                 if (type == NULL)
 433                         continue;
 434                 if (strcmp(type, "md_image") && strcmp(type, "mfs_root"))
 435                         continue;
 436                 c = preload_search_info(mod, MODINFO_ADDR);
 437                 ptr = *(u_char **)c;
 438                 c = preload_search_info(mod, MODINFO_SIZE);
 439                 len = *(unsigned *)c;
 440                 kprintf("md%d: Preloaded image <%s> %d bytes at %p\n",
 441                    mdunits, name, len, ptr);
 442                 mdcreate_preload(ptr, len);
 443         }
 444         mdcreate_malloc();
 445 }
 446
 447 SYSINIT(mddev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR, md_drvinit,NULL)
 448
 449 #ifdef MD_ROOT
 450 static void
 451 md_takeroot(void *junk)
 452 {
 453         if (mdrootready)
 454                 rootdevnames[0] = "ufs:/dev/md0s0";
 455 }
 456
 457 SYSINIT(md_root, SI_SUB_MOUNT_ROOT, SI_ORDER_FIRST, md_takeroot, NULL);
 458 #endif