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 1.16 2007/05/15 00:01:03 dillon 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         struct disk_info info;
  95
  96         if (md_debug)
  97                 kprintf("mdopen(%s %x %x)\n",
  98                         devtoname(dev), ap->a_oflags, ap->a_devtype);
  99
 100         sc = dev->si_drv1;
 101         if (sc->unit + 1 == mdunits)
 102                 mdcreate_malloc();
 103
 104         bzero(&info, sizeof(info));
 105         info.d_media_blksize = DEV_BSIZE;       /* mandatory */
 106         info.d_media_blocks = sc->nsect;
 107
 108         info.d_secpertrack = 1024;              /* optional */
 109         info.d_nheads = 1;
 110         info.d_secpercyl = info.d_secpertrack * info.d_nheads;
 111         info.d_ncylinders = (u_int)(info.d_media_blocks / info.d_secpercyl);
 112         disk_setdiskinfo(&sc->disk, &info);
 113
 114         return (0);
 115 }
 116
 117 static int
 118 mdioctl(struct dev_ioctl_args *ap)
 119 {
 120         cdev_t dev = ap->a_head.a_dev;
 121
 122         if (md_debug)
 123                 kprintf("mdioctl(%s %lx %p %x)\n",
 124                         devtoname(dev), ap->a_cmd, ap->a_data, ap->a_fflag);
 125
 126         return (ENOIOCTL);
 127 }
 128
 129 static int
 130 mdstrategy(struct dev_strategy_args *ap)
 131 {
 132         cdev_t dev = ap->a_head.a_dev;
 133         struct bio *bio = ap->a_bio;
 134         struct buf *bp = bio->bio_buf;
 135         struct md_s *sc;
 136
 137         if (md_debug > 1) {
 138                 kprintf("mdstrategy(%p) %s %08x, %lld, %d, %p)\n",
 139                     bp, devtoname(dev), bp->b_flags, bio->bio_offset,
 140                     bp->b_bcount, bp->b_data);
 141         }
 142         bio->bio_driver_info = dev;
 143         sc = dev->si_drv1;
 144         if (sc->type == MD_MALLOC) {
 145                 mdstrategy_malloc(ap);
 146         } else {
 147                 mdstrategy_preload(ap);
 148         }
 149         return(0);
 150 }
 151
 152
 153 static int
 154 mdstrategy_malloc(struct dev_strategy_args *ap)
 155 {
 156         cdev_t dev = ap->a_head.a_dev;
 157         struct bio *bio = ap->a_bio;
 158         struct buf *bp = bio->bio_buf;
 159         unsigned secno, nsec, secval, uc;
 160         u_char *secp, **secpp, *dst;
 161         devstat_trans_flags dop;
 162         struct md_s *sc;
 163         int i;
 164
 165         if (md_debug > 1)
 166                 kprintf("mdstrategy_malloc(%p) %s %08xx, %lld, %d, %p)\n",
 167                     bp, devtoname(dev), bp->b_flags, bio->bio_offset,
 168                     bp->b_bcount, bp->b_data);
 169
 170         sc = dev->si_drv1;
 171
 172         crit_enter();
 173
 174         bioqdisksort(&sc->bio_queue, bio);
 175
 176         if (sc->busy) {
 177                 crit_exit();
 178                 return(0);
 179         }
 180
 181         sc->busy++;
 182
 183         while (1) {
 184                 bio = bioq_first(&sc->bio_queue);
 185                 if (bp)
 186                         bioq_remove(&sc->bio_queue, bio);
 187                 crit_exit();
 188                 if (bio == NULL)
 189                         break;
 190
 191                 devstat_start_transaction(&sc->stats);
 192
 193                 switch(bp->b_cmd) {
 194                 case BUF_CMD_FREEBLKS:
 195                         dop = DEVSTAT_NO_DATA;
 196                         break;
 197                 case BUF_CMD_READ:
 198                         dop = DEVSTAT_READ;
 199                         break;
 200                 case BUF_CMD_WRITE:
 201                         dop = DEVSTAT_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)*secpp > 255) {
 214                                         secp = *secpp;
 215                                         secval = 0;
 216                                 } else {
 217                                         secp = 0;
 218                                         secval = (u_int) *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 *)uc;
 256                                 } else {
 257                                         if (!secpp) {
 258                                                 MALLOC(secpp, u_char **, (secno + nsec + 1) * sizeof(u_char *), M_MD, M_WAITOK);
 259                                                 bzero(secpp, (secno + nsec + 1) * sizeof(u_char *));
 260                                                 bcopy(sc->secp, secpp, sc->nsecp * sizeof(u_char *));
 261                                                 FREE(sc->secp, M_MD);
 262                                                 sc->secp = secpp;
 263                                                 sc->nsecp = secno + nsec + 1;
 264                                                 secpp = &sc->secp[secno];
 265                                         }
 266                                         if (i == DEV_BSIZE) {
 267                                                 if (secp)
 268                                                         FREE(secp, M_MDSECT);
 269                                                 *secpp = (u_char *)uc;
 270                                         } else {
 271                                                 if (!secp)
 272                                                         MALLOC(secp, u_char *, DEV_BSIZE, M_MDSECT, M_WAITOK);
 273                                                 bcopy(dst, secp, DEV_BSIZE);
 274
 275                                                 *secpp = secp;
 276                                         }
 277                                 }
 278                                 break;
 279                         default:
 280                                 panic("md: bad b_cmd %d", bp->b_cmd);
 281
 282                         }
 283                         secno++;
 284                         dst += DEV_BSIZE;
 285                 }
 286                 bp->b_resid = 0;
 287                 devstat_end_transaction_buf(&sc->stats, bp);
 288                 biodone(bio);
 289                 crit_enter();
 290         }
 291         sc->busy = 0;
 292         return(0);
 293 }
 294
 295
 296 static int
 297 mdstrategy_preload(struct dev_strategy_args *ap)
 298 {
 299         cdev_t dev = ap->a_head.a_dev;
 300         struct bio *bio = ap->a_bio;
 301         struct buf *bp = bio->bio_buf;
 302         devstat_trans_flags dop;
 303         struct md_s *sc;
 304
 305         if (md_debug > 1)
 306                 kprintf("mdstrategy_preload(%p) %s %08x, %lld, %d, %p)\n",
 307                     bp, devtoname(dev), bp->b_flags, bio->bio_offset,
 308                     bp->b_bcount, bp->b_data);
 309
 310         sc = dev->si_drv1;
 311
 312         crit_enter();
 313
 314         bioqdisksort(&sc->bio_queue, bio);
 315
 316         if (sc->busy) {
 317                 crit_exit();
 318                 return(0);
 319         }
 320
 321         sc->busy++;
 322
 323         while (1) {
 324                 bio = bioq_first(&sc->bio_queue);
 325                 if (bio)
 326                         bioq_remove(&sc->bio_queue, bio);
 327                 crit_exit();
 328                 if (bio == NULL)
 329                         break;
 330
 331                 devstat_start_transaction(&sc->stats);
 332
 333                 switch(bp->b_cmd) {
 334                 case BUF_CMD_FREEBLKS:
 335                         dop = DEVSTAT_NO_DATA;
 336                         break;
 337                 case BUF_CMD_READ:
 338                         dop = DEVSTAT_READ;
 339                         bcopy(sc->pl_ptr + bio->bio_offset,
 340                                bp->b_data, bp->b_bcount);
 341                         break;
 342                 case BUF_CMD_WRITE:
 343                         dop = DEVSTAT_WRITE;
 344                         bcopy(bp->b_data, sc->pl_ptr + bio->bio_offset,
 345                               bp->b_bcount);
 346                         break;
 347                 default:
 348                         panic("md: bad cmd %d\n", bp->b_cmd);
 349                 }
 350                 bp->b_resid = 0;
 351                 devstat_end_transaction_buf(&sc->stats, bp);
 352                 biodone(bio);
 353                 crit_enter();
 354         }
 355         sc->busy = 0;
 356         return(0);
 357 }
 358
 359 static struct md_s *
 360 mdcreate(void)
 361 {
 362         struct md_s *sc;
 363
 364         MALLOC(sc, struct md_s *,sizeof(*sc), M_MD, M_WAITOK);
 365         bzero(sc, sizeof(*sc));
 366         sc->unit = mdunits++;
 367         bioq_init(&sc->bio_queue);
 368         devstat_add_entry(&sc->stats, "md", sc->unit, DEV_BSIZE,
 369                 DEVSTAT_NO_ORDERED_TAGS,
 370                 DEVSTAT_TYPE_DIRECT | DEVSTAT_TYPE_IF_OTHER,
 371                 DEVSTAT_PRIORITY_OTHER);
 372         sc->dev = disk_create(sc->unit, &sc->disk, &md_ops);
 373         sc->dev->si_drv1 = sc;
 374         return (sc);
 375 }
 376
 377 static void
 378 mdcreate_preload(u_char *image, unsigned length)
 379 {
 380         struct md_s *sc;
 381
 382         sc = mdcreate();
 383         sc->type = MD_PRELOAD;
 384         sc->nsect = length / DEV_BSIZE;
 385         sc->pl_ptr = image;
 386         sc->pl_len = length;
 387
 388         if (sc->unit == 0)
 389                 mdrootready = 1;
 390 }
 391
 392 static void
 393 mdcreate_malloc(void)
 394 {
 395         struct md_s *sc;
 396
 397         sc = mdcreate();
 398         sc->type = MD_MALLOC;
 399
 400         sc->nsect = MD_NSECT;   /* for now */
 401         MALLOC(sc->secp, u_char **, sizeof(u_char *), M_MD, M_WAITOK);
 402         bzero(sc->secp, sizeof(u_char *));
 403         sc->nsecp = 1;
 404         kprintf("md%d: Malloc disk\n", sc->unit);
 405 }
 406
 407 static void
 408 md_drvinit(void *unused)
 409 {
 410
 411         caddr_t mod;
 412         caddr_t c;
 413         u_char *ptr, *name, *type;
 414         unsigned len;
 415
 416 #ifdef MD_ROOT_SIZE
 417         mdcreate_preload(mfs_root, MD_ROOT_SIZE*1024);
 418 #endif
 419         mod = NULL;
 420         while ((mod = preload_search_next_name(mod)) != NULL) {
 421                 name = (char *)preload_search_info(mod, MODINFO_NAME);
 422                 type = (char *)preload_search_info(mod, MODINFO_TYPE);
 423                 if (name == NULL)
 424                         continue;
 425                 if (type == NULL)
 426                         continue;
 427                 if (strcmp(type, "md_image") && strcmp(type, "mfs_root"))
 428                         continue;
 429                 c = preload_search_info(mod, MODINFO_ADDR);
 430                 ptr = *(u_char **)c;
 431                 c = preload_search_info(mod, MODINFO_SIZE);
 432                 len = *(unsigned *)c;
 433                 kprintf("md%d: Preloaded image <%s> %d bytes at %p\n",
 434                    mdunits, name, len, ptr);
 435                 mdcreate_preload(ptr, len);
 436         }
 437         mdcreate_malloc();
 438 }
 439
 440 SYSINIT(mddev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR, md_drvinit,NULL)
 441
 442 #ifdef MD_ROOT
 443 static void
 444 md_takeroot(void *junk)
 445 {
 446         if (mdrootready)
 447                 rootdevnames[0] = "ufs:/dev/md0c";
 448 }
 449
 450 SYSINIT(md_root, SI_SUB_MOUNT_ROOT, SI_ORDER_FIRST, md_takeroot, NULL);
 451 #endif