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 1.18 2007/09/05 05:28:32 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 (bio == NULL) {
 186                         crit_exit();
 187                         break;
 188                 }
 189                 crit_exit();
 190                 bioq_remove(&sc->bio_queue, bio);
 191                 bp = bio->bio_buf;
 192
 193                 devstat_start_transaction(&sc->stats);
 194
 195                 switch(bp->b_cmd) {
 196                 case BUF_CMD_FREEBLKS:
 197                         dop = DEVSTAT_NO_DATA;
 198                         break;
 199                 case BUF_CMD_READ:
 200                         dop = DEVSTAT_READ;
 201                         break;
 202                 case BUF_CMD_WRITE:
 203                         dop = DEVSTAT_WRITE;
 204                         break;
 205                 default:
 206                         panic("md: bad b_cmd %d", bp->b_cmd);
 207                 }
 208
 209                 nsec = bp->b_bcount >> DEV_BSHIFT;
 210                 secno = (unsigned)(bio->bio_offset >> DEV_BSHIFT);
 211                 dst = bp->b_data;
 212                 while (nsec--) {
 213                         if (secno < sc->nsecp) {
 214                                 secpp = &sc->secp[secno];
 215                                 if ((u_int)*secpp > 255) {
 216                                         secp = *secpp;
 217                                         secval = 0;
 218                                 } else {
 219                                         secp = 0;
 220                                         secval = (u_int) *secpp;
 221                                 }
 222                         } else {
 223                                 secpp = 0;
 224                                 secp = 0;
 225                                 secval = 0;
 226                         }
 227                         if (md_debug > 2)
 228                                 kprintf("%08x %p %p %d\n", bp->b_flags, secpp, secp, secval);
 229
 230                         switch(bp->b_cmd) {
 231                         case BUF_CMD_FREEBLKS:
 232                                 if (secpp) {
 233                                         if (secp)
 234                                                 FREE(secp, M_MDSECT);
 235                                         *secpp = 0;
 236                                 }
 237                                 break;
 238                         case BUF_CMD_READ:
 239                                 if (secp) {
 240                                         bcopy(secp, dst, DEV_BSIZE);
 241                                 } else if (secval) {
 242                                         for (i = 0; i < DEV_BSIZE; i++)
 243                                                 dst[i] = secval;
 244                                 } else {
 245                                         bzero(dst, DEV_BSIZE);
 246                                 }
 247                                 break;
 248                         case BUF_CMD_WRITE:
 249                                 uc = dst[0];
 250                                 for (i = 1; i < DEV_BSIZE; i++)
 251                                         if (dst[i] != uc)
 252                                                 break;
 253                                 if (i == DEV_BSIZE && !uc) {
 254                                         if (secp)
 255                                                 FREE(secp, M_MDSECT);
 256                                         if (secpp)
 257                                                 *secpp = (u_char *)uc;
 258                                 } else {
 259                                         if (!secpp) {
 260                                                 MALLOC(secpp, u_char **, (secno + nsec + 1) * sizeof(u_char *), M_MD, M_WAITOK);
 261                                                 bzero(secpp, (secno + nsec + 1) * sizeof(u_char *));
 262                                                 bcopy(sc->secp, secpp, sc->nsecp * sizeof(u_char *));
 263                                                 FREE(sc->secp, M_MD);
 264                                                 sc->secp = secpp;
 265                                                 sc->nsecp = secno + nsec + 1;
 266                                                 secpp = &sc->secp[secno];
 267                                         }
 268                                         if (i == DEV_BSIZE) {
 269                                                 if (secp)
 270                                                         FREE(secp, M_MDSECT);
 271                                                 *secpp = (u_char *)uc;
 272                                         } else {
 273                                                 if (!secp)
 274                                                         MALLOC(secp, u_char *, DEV_BSIZE, M_MDSECT, M_WAITOK);
 275                                                 bcopy(dst, secp, DEV_BSIZE);
 276
 277                                                 *secpp = secp;
 278                                         }
 279                                 }
 280                                 break;
 281                         default:
 282                                 panic("md: bad b_cmd %d", bp->b_cmd);
 283
 284                         }
 285                         secno++;
 286                         dst += DEV_BSIZE;
 287                 }
 288                 bp->b_resid = 0;
 289                 devstat_end_transaction_buf(&sc->stats, bp);
 290                 biodone(bio);
 291                 crit_enter();
 292         }
 293         sc->busy = 0;
 294         return(0);
 295 }
 296
 297
 298 static int
 299 mdstrategy_preload(struct dev_strategy_args *ap)
 300 {
 301         cdev_t dev = ap->a_head.a_dev;
 302         struct bio *bio = ap->a_bio;
 303         struct buf *bp = bio->bio_buf;
 304         devstat_trans_flags dop;
 305         struct md_s *sc;
 306
 307         if (md_debug > 1)
 308                 kprintf("mdstrategy_preload(%p) %s %08x, %lld, %d, %p)\n",
 309                     bp, devtoname(dev), bp->b_flags, bio->bio_offset,
 310                     bp->b_bcount, bp->b_data);
 311
 312         sc = dev->si_drv1;
 313
 314         crit_enter();
 315
 316         bioqdisksort(&sc->bio_queue, bio);
 317
 318         if (sc->busy) {
 319                 crit_exit();
 320                 return(0);
 321         }
 322
 323         sc->busy++;
 324
 325         while (1) {
 326                 bio = bioq_first(&sc->bio_queue);
 327                 if (bio)
 328                         bioq_remove(&sc->bio_queue, bio);
 329                 crit_exit();
 330                 if (bio == NULL)
 331                         break;
 332
 333                 devstat_start_transaction(&sc->stats);
 334
 335                 switch(bp->b_cmd) {
 336                 case BUF_CMD_FREEBLKS:
 337                         dop = DEVSTAT_NO_DATA;
 338                         break;
 339                 case BUF_CMD_READ:
 340                         dop = DEVSTAT_READ;
 341                         bcopy(sc->pl_ptr + bio->bio_offset,
 342                                bp->b_data, bp->b_bcount);
 343                         break;
 344                 case BUF_CMD_WRITE:
 345                         dop = DEVSTAT_WRITE;
 346                         bcopy(bp->b_data, sc->pl_ptr + bio->bio_offset,
 347                               bp->b_bcount);
 348                         break;
 349                 default:
 350                         panic("md: bad cmd %d\n", bp->b_cmd);
 351                 }
 352                 bp->b_resid = 0;
 353                 devstat_end_transaction_buf(&sc->stats, bp);
 354                 biodone(bio);
 355                 crit_enter();
 356         }
 357         sc->busy = 0;
 358         return(0);
 359 }
 360
 361 static struct md_s *
 362 mdcreate(void)
 363 {
 364         struct md_s *sc;
 365
 366         MALLOC(sc, struct md_s *,sizeof(*sc), M_MD, M_WAITOK);
 367         bzero(sc, sizeof(*sc));
 368         sc->unit = mdunits++;
 369         bioq_init(&sc->bio_queue);
 370         devstat_add_entry(&sc->stats, "md", sc->unit, DEV_BSIZE,
 371                 DEVSTAT_NO_ORDERED_TAGS,
 372                 DEVSTAT_TYPE_DIRECT | DEVSTAT_TYPE_IF_OTHER,
 373                 DEVSTAT_PRIORITY_OTHER);
 374         sc->dev = disk_create(sc->unit, &sc->disk, &md_ops);
 375         sc->dev->si_drv1 = sc;
 376         sc->dev->si_iosize_max = DFLTPHYS;
 377
 378         return (sc);
 379 }
 380
 381 static void
 382 mdcreate_preload(u_char *image, unsigned length)
 383 {
 384         struct md_s *sc;
 385
 386         sc = mdcreate();
 387         sc->type = MD_PRELOAD;
 388         sc->nsect = length / DEV_BSIZE;
 389         sc->pl_ptr = image;
 390         sc->pl_len = length;
 391
 392         if (sc->unit == 0)
 393                 mdrootready = 1;
 394 }
 395
 396 static void
 397 mdcreate_malloc(void)
 398 {
 399         struct md_s *sc;
 400
 401         sc = mdcreate();
 402         sc->type = MD_MALLOC;
 403
 404         sc->nsect = MD_NSECT;   /* for now */
 405         MALLOC(sc->secp, u_char **, sizeof(u_char *), M_MD, M_WAITOK);
 406         bzero(sc->secp, sizeof(u_char *));
 407         sc->nsecp = 1;
 408         kprintf("md%d: Malloc disk\n", sc->unit);
 409 }
 410
 411 static void
 412 md_drvinit(void *unused)
 413 {
 414
 415         caddr_t mod;
 416         caddr_t c;
 417         u_char *ptr, *name, *type;
 418         unsigned len;
 419
 420 #ifdef MD_ROOT_SIZE
 421         mdcreate_preload(mfs_root, MD_ROOT_SIZE*1024);
 422 #endif
 423         mod = NULL;
 424         while ((mod = preload_search_next_name(mod)) != NULL) {
 425                 name = (char *)preload_search_info(mod, MODINFO_NAME);
 426                 type = (char *)preload_search_info(mod, MODINFO_TYPE);
 427                 if (name == NULL)
 428                         continue;
 429                 if (type == NULL)
 430                         continue;
 431                 if (strcmp(type, "md_image") && strcmp(type, "mfs_root"))
 432                         continue;
 433                 c = preload_search_info(mod, MODINFO_ADDR);
 434                 ptr = *(u_char **)c;
 435                 c = preload_search_info(mod, MODINFO_SIZE);
 436                 len = *(unsigned *)c;
 437                 kprintf("md%d: Preloaded image <%s> %d bytes at %p\n",
 438                    mdunits, name, len, ptr);
 439                 mdcreate_preload(ptr, len);
 440         }
 441         mdcreate_malloc();
 442 }
 443
 444 SYSINIT(mddev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR, md_drvinit,NULL)
 445
 446 #ifdef MD_ROOT
 447 static void
 448 md_takeroot(void *junk)
 449 {
 450         if (mdrootready)
 451                 rootdevnames[0] = "ufs:/dev/md0c";
 452 }
 453
 454 SYSINIT(md_root, SI_SUB_MOUNT_ROOT, SI_ORDER_FIRST, md_takeroot, NULL);
 455 #endif