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         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         struct md_s *sc;
 162         int i;
 163
 164         if (md_debug > 1)
 165                 kprintf("mdstrategy_malloc(%p) %s %08xx, %lld, %d, %p)\n",
 166                     bp, devtoname(dev), bp->b_flags, bio->bio_offset,
 167                     bp->b_bcount, bp->b_data);
 168
 169         sc = dev->si_drv1;
 170
 171         crit_enter();
 172
 173         bioqdisksort(&sc->bio_queue, bio);
 174
 175         if (sc->busy) {
 176                 crit_exit();
 177                 return(0);
 178         }
 179
 180         sc->busy++;
 181
 182         while (1) {
 183                 bio = bioq_first(&sc->bio_queue);
 184                 if (bio == NULL) {
 185                         crit_exit();
 186                         break;
 187                 }
 188                 crit_exit();
 189                 bioq_remove(&sc->bio_queue, bio);
 190                 bp = bio->bio_buf;
 191
 192                 devstat_start_transaction(&sc->stats);
 193
 194                 switch (bp->b_cmd) {
 195                 case BUF_CMD_FREEBLKS:
 196                 case BUF_CMD_READ:
 197                 case BUF_CMD_WRITE:
 198                         break;
 199                 default:
 200                         panic("md: bad b_cmd %d", bp->b_cmd);
 201                 }
 202
 203                 nsec = bp->b_bcount >> DEV_BSHIFT;
 204                 secno = (unsigned)(bio->bio_offset >> DEV_BSHIFT);
 205                 dst = bp->b_data;
 206                 while (nsec--) {
 207                         if (secno < sc->nsecp) {
 208                                 secpp = &sc->secp[secno];
 209                                 if ((u_int)*secpp > 255) {
 210                                         secp = *secpp;
 211                                         secval = 0;
 212                                 } else {
 213                                         secp = 0;
 214                                         secval = (u_int) *secpp;
 215                                 }
 216                         } else {
 217                                 secpp = 0;
 218                                 secp = 0;
 219                                 secval = 0;
 220                         }
 221                         if (md_debug > 2)
 222                                 kprintf("%08x %p %p %d\n", bp->b_flags, secpp, secp, secval);
 223
 224                         switch (bp->b_cmd) {
 225                         case BUF_CMD_FREEBLKS:
 226                                 if (secpp) {
 227                                         if (secp)
 228                                                 FREE(secp, M_MDSECT);
 229                                         *secpp = 0;
 230                                 }
 231                                 break;
 232                         case BUF_CMD_READ:
 233                                 if (secp) {
 234                                         bcopy(secp, dst, DEV_BSIZE);
 235                                 } else if (secval) {
 236                                         for (i = 0; i < DEV_BSIZE; i++)
 237                                                 dst[i] = secval;
 238                                 } else {
 239                                         bzero(dst, DEV_BSIZE);
 240                                 }
 241                                 break;
 242                         case BUF_CMD_WRITE:
 243                                 uc = dst[0];
 244                                 for (i = 1; i < DEV_BSIZE; i++)
 245                                         if (dst[i] != uc)
 246                                                 break;
 247                                 if (i == DEV_BSIZE && !uc) {
 248                                         if (secp)
 249                                                 FREE(secp, M_MDSECT);
 250                                         if (secpp)
 251                                                 *secpp = (u_char *)uc;
 252                                 } else {
 253                                         if (!secpp) {
 254                                                 MALLOC(secpp, u_char **, (secno + nsec + 1) * sizeof(u_char *), M_MD, M_WAITOK | M_ZERO);
 255                                                 bcopy(sc->secp, secpp, sc->nsecp * sizeof(u_char *));
 256                                                 FREE(sc->secp, M_MD);
 257                                                 sc->secp = secpp;
 258                                                 sc->nsecp = secno + nsec + 1;
 259                                                 secpp = &sc->secp[secno];
 260                                         }
 261                                         if (i == DEV_BSIZE) {
 262                                                 if (secp)
 263                                                         FREE(secp, M_MDSECT);
 264                                                 *secpp = (u_char *)uc;
 265                                         } else {
 266                                                 if (!secp)
 267                                                         MALLOC(secp, u_char *, DEV_BSIZE, M_MDSECT, M_WAITOK);
 268                                                 bcopy(dst, secp, DEV_BSIZE);
 269
 270                                                 *secpp = secp;
 271                                         }
 272                                 }
 273                                 break;
 274                         default:
 275                                 panic("md: bad b_cmd %d", bp->b_cmd);
 276
 277                         }
 278                         secno++;
 279                         dst += DEV_BSIZE;
 280                 }
 281                 bp->b_resid = 0;
 282                 devstat_end_transaction_buf(&sc->stats, bp);
 283                 biodone(bio);
 284                 crit_enter();
 285         }
 286         sc->busy = 0;
 287         return(0);
 288 }
 289
 290
 291 static int
 292 mdstrategy_preload(struct dev_strategy_args *ap)
 293 {
 294         cdev_t dev = ap->a_head.a_dev;
 295         struct bio *bio = ap->a_bio;
 296         struct buf *bp = bio->bio_buf;
 297         struct md_s *sc;
 298
 299         if (md_debug > 1)
 300                 kprintf("mdstrategy_preload(%p) %s %08x, %lld, %d, %p)\n",
 301                     bp, devtoname(dev), bp->b_flags, bio->bio_offset,
 302                     bp->b_bcount, bp->b_data);
 303
 304         sc = dev->si_drv1;
 305
 306         crit_enter();
 307
 308         bioqdisksort(&sc->bio_queue, bio);
 309
 310         if (sc->busy) {
 311                 crit_exit();
 312                 return(0);
 313         }
 314
 315         sc->busy++;
 316
 317         while (1) {
 318                 bio = bioq_first(&sc->bio_queue);
 319                 if (bio)
 320                         bioq_remove(&sc->bio_queue, bio);
 321                 crit_exit();
 322                 if (bio == NULL)
 323                         break;
 324
 325                 devstat_start_transaction(&sc->stats);
 326
 327                 switch (bp->b_cmd) {
 328                 case BUF_CMD_FREEBLKS:
 329                         break;
 330                 case BUF_CMD_READ:
 331                         bcopy(sc->pl_ptr + bio->bio_offset,
 332                                bp->b_data, bp->b_bcount);
 333                         break;
 334                 case BUF_CMD_WRITE:
 335                         bcopy(bp->b_data, sc->pl_ptr + bio->bio_offset,
 336                               bp->b_bcount);
 337                         break;
 338                 default:
 339                         panic("md: bad cmd %d\n", bp->b_cmd);
 340                 }
 341                 bp->b_resid = 0;
 342                 devstat_end_transaction_buf(&sc->stats, bp);
 343                 biodone(bio);
 344                 crit_enter();
 345         }
 346         sc->busy = 0;
 347         return(0);
 348 }
 349
 350 static struct md_s *
 351 mdcreate(void)
 352 {
 353         struct md_s *sc;
 354
 355         MALLOC(sc, struct md_s *,sizeof(*sc), M_MD, M_WAITOK | M_ZERO);
 356         sc->unit = mdunits++;
 357         bioq_init(&sc->bio_queue);
 358         devstat_add_entry(&sc->stats, "md", sc->unit, DEV_BSIZE,
 359                 DEVSTAT_NO_ORDERED_TAGS,
 360                 DEVSTAT_TYPE_DIRECT | DEVSTAT_TYPE_IF_OTHER,
 361                 DEVSTAT_PRIORITY_OTHER);
 362         sc->dev = disk_create(sc->unit, &sc->disk, &md_ops);
 363         sc->dev->si_drv1 = sc;
 364         sc->dev->si_iosize_max = DFLTPHYS;
 365
 366         return (sc);
 367 }
 368
 369 static void
 370 mdcreate_preload(u_char *image, unsigned length)
 371 {
 372         struct md_s *sc;
 373
 374         sc = mdcreate();
 375         sc->type = MD_PRELOAD;
 376         sc->nsect = length / DEV_BSIZE;
 377         sc->pl_ptr = image;
 378         sc->pl_len = length;
 379
 380         if (sc->unit == 0)
 381                 mdrootready = 1;
 382 }
 383
 384 static void
 385 mdcreate_malloc(void)
 386 {
 387         struct md_s *sc;
 388
 389         sc = mdcreate();
 390         sc->type = MD_MALLOC;
 391
 392         sc->nsect = MD_NSECT;   /* for now */
 393         MALLOC(sc->secp, u_char **, sizeof(u_char *), M_MD, M_WAITOK | M_ZERO);
 394         sc->nsecp = 1;
 395         kprintf("md%d: Malloc disk\n", sc->unit);
 396 }
 397
 398 static void
 399 md_drvinit(void *unused)
 400 {
 401
 402         caddr_t mod;
 403         caddr_t c;
 404         u_char *ptr, *name, *type;
 405         unsigned len;
 406
 407 #ifdef MD_ROOT_SIZE
 408         mdcreate_preload(mfs_root, MD_ROOT_SIZE*1024);
 409 #endif
 410         mod = NULL;
 411         while ((mod = preload_search_next_name(mod)) != NULL) {
 412                 name = (char *)preload_search_info(mod, MODINFO_NAME);
 413                 type = (char *)preload_search_info(mod, MODINFO_TYPE);
 414                 if (name == NULL)
 415                         continue;
 416                 if (type == NULL)
 417                         continue;
 418                 if (strcmp(type, "md_image") && strcmp(type, "mfs_root"))
 419                         continue;
 420                 c = preload_search_info(mod, MODINFO_ADDR);
 421                 ptr = *(u_char **)c;
 422                 c = preload_search_info(mod, MODINFO_SIZE);
 423                 len = *(unsigned *)c;
 424                 kprintf("md%d: Preloaded image <%s> %d bytes at %p\n",
 425                    mdunits, name, len, ptr);
 426                 mdcreate_preload(ptr, len);
 427         }
 428         mdcreate_malloc();
 429 }
 430
 431 SYSINIT(mddev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR, md_drvinit,NULL)
 432
 433 #ifdef MD_ROOT
 434 static void
 435 md_takeroot(void *junk)
 436 {
 437         if (mdrootready)
 438                 rootdevnames[0] = "ufs:/dev/md0c";
 439 }
 440
 441 SYSINIT(md_root, SI_SUB_MOUNT_ROOT, SI_ORDER_FIRST, md_takeroot, NULL);
 442 #endif