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 1.15 2006/12/22 23:26:16 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 disklabel *dl;
  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         dl = &sc->disk.d_label;
 105         bzero(dl, sizeof(*dl));
 106         dl->d_secsize = DEV_BSIZE;
 107         dl->d_nsectors = 1024;
 108         dl->d_ntracks = 1;
 109         dl->d_secpercyl = dl->d_nsectors * dl->d_ntracks;
 110         dl->d_secperunit = sc->nsect;
 111         dl->d_ncylinders = dl->d_secperunit / dl->d_secpercyl;
 112         return (0);
 113 }
 114
 115 static int
 116 mdioctl(struct dev_ioctl_args *ap)
 117 {
 118         cdev_t dev = ap->a_head.a_dev;
 119
 120         if (md_debug)
 121                 kprintf("mdioctl(%s %lx %p %x)\n",
 122                         devtoname(dev), ap->a_cmd, ap->a_data, ap->a_fflag);
 123
 124         return (ENOIOCTL);
 125 }
 126
 127 static int
 128 mdstrategy(struct dev_strategy_args *ap)
 129 {
 130         cdev_t dev = ap->a_head.a_dev;
 131         struct bio *bio = ap->a_bio;
 132         struct buf *bp = bio->bio_buf;
 133         struct md_s *sc;
 134
 135         if (md_debug > 1) {
 136                 kprintf("mdstrategy(%p) %s %08x, %lld, %d, %p)\n",
 137                     bp, devtoname(dev), bp->b_flags, bio->bio_offset,
 138                     bp->b_bcount, bp->b_data);
 139         }
 140         bio->bio_driver_info = dev;
 141         sc = dev->si_drv1;
 142         if (sc->type == MD_MALLOC) {
 143                 mdstrategy_malloc(ap);
 144         } else {
 145                 mdstrategy_preload(ap);
 146         }
 147         return(0);
 148 }
 149
 150
 151 static int
 152 mdstrategy_malloc(struct dev_strategy_args *ap)
 153 {
 154         cdev_t dev = ap->a_head.a_dev;
 155         struct bio *bio = ap->a_bio;
 156         struct buf *bp = bio->bio_buf;
 157         unsigned secno, nsec, secval, uc;
 158         u_char *secp, **secpp, *dst;
 159         devstat_trans_flags dop;
 160         struct md_s *sc;
 161         int i;
 162
 163         if (md_debug > 1)
 164                 kprintf("mdstrategy_malloc(%p) %s %08xx, %lld, %d, %p)\n",
 165                     bp, devtoname(dev), bp->b_flags, bio->bio_offset,
 166                     bp->b_bcount, bp->b_data);
 167
 168         sc = dev->si_drv1;
 169
 170         crit_enter();
 171
 172         bioqdisksort(&sc->bio_queue, bio);
 173
 174         if (sc->busy) {
 175                 crit_exit();
 176                 return(0);
 177         }
 178
 179         sc->busy++;
 180
 181         while (1) {
 182                 bio = bioq_first(&sc->bio_queue);
 183                 if (bp)
 184                         bioq_remove(&sc->bio_queue, bio);
 185                 crit_exit();
 186                 if (bio == NULL)
 187                         break;
 188
 189                 devstat_start_transaction(&sc->stats);
 190
 191                 switch(bp->b_cmd) {
 192                 case BUF_CMD_FREEBLKS:
 193                         dop = DEVSTAT_NO_DATA;
 194                         break;
 195                 case BUF_CMD_READ:
 196                         dop = DEVSTAT_READ;
 197                         break;
 198                 case BUF_CMD_WRITE:
 199                         dop = DEVSTAT_WRITE;
 200                         break;
 201                 default:
 202                         panic("md: bad b_cmd %d", bp->b_cmd);
 203                 }
 204
 205                 nsec = bp->b_bcount >> DEV_BSHIFT;
 206                 secno = (unsigned)(bio->bio_offset >> DEV_BSHIFT);
 207                 dst = bp->b_data;
 208                 while (nsec--) {
 209                         if (secno < sc->nsecp) {
 210                                 secpp = &sc->secp[secno];
 211                                 if ((u_int)*secpp > 255) {
 212                                         secp = *secpp;
 213                                         secval = 0;
 214                                 } else {
 215                                         secp = 0;
 216                                         secval = (u_int) *secpp;
 217                                 }
 218                         } else {
 219                                 secpp = 0;
 220                                 secp = 0;
 221                                 secval = 0;
 222                         }
 223                         if (md_debug > 2)
 224                                 kprintf("%08x %p %p %d\n", bp->b_flags, secpp, secp, secval);
 225
 226                         switch(bp->b_cmd) {
 227                         case BUF_CMD_FREEBLKS:
 228                                 if (secpp) {
 229                                         if (secp)
 230                                                 FREE(secp, M_MDSECT);
 231                                         *secpp = 0;
 232                                 }
 233                                 break;
 234                         case BUF_CMD_READ:
 235                                 if (secp) {
 236                                         bcopy(secp, dst, DEV_BSIZE);
 237                                 } else if (secval) {
 238                                         for (i = 0; i < DEV_BSIZE; i++)
 239                                                 dst[i] = secval;
 240                                 } else {
 241                                         bzero(dst, DEV_BSIZE);
 242                                 }
 243                                 break;
 244                         case BUF_CMD_WRITE:
 245                                 uc = dst[0];
 246                                 for (i = 1; i < DEV_BSIZE; i++)
 247                                         if (dst[i] != uc)
 248                                                 break;
 249                                 if (i == DEV_BSIZE && !uc) {
 250                                         if (secp)
 251                                                 FREE(secp, M_MDSECT);
 252                                         if (secpp)
 253                                                 *secpp = (u_char *)uc;
 254                                 } else {
 255                                         if (!secpp) {
 256                                                 MALLOC(secpp, u_char **, (secno + nsec + 1) * sizeof(u_char *), M_MD, M_WAITOK);
 257                                                 bzero(secpp, (secno + nsec + 1) * sizeof(u_char *));
 258                                                 bcopy(sc->secp, secpp, sc->nsecp * sizeof(u_char *));
 259                                                 FREE(sc->secp, M_MD);
 260                                                 sc->secp = secpp;
 261                                                 sc->nsecp = secno + nsec + 1;
 262                                                 secpp = &sc->secp[secno];
 263                                         }
 264                                         if (i == DEV_BSIZE) {
 265                                                 if (secp)
 266                                                         FREE(secp, M_MDSECT);
 267                                                 *secpp = (u_char *)uc;
 268                                         } else {
 269                                                 if (!secp)
 270                                                         MALLOC(secp, u_char *, DEV_BSIZE, M_MDSECT, M_WAITOK);
 271                                                 bcopy(dst, secp, DEV_BSIZE);
 272
 273                                                 *secpp = secp;
 274                                         }
 275                                 }
 276                                 break;
 277                         default:
 278                                 panic("md: bad b_cmd %d", bp->b_cmd);
 279
 280                         }
 281                         secno++;
 282                         dst += DEV_BSIZE;
 283                 }
 284                 bp->b_resid = 0;
 285                 devstat_end_transaction_buf(&sc->stats, bp);
 286                 biodone(bio);
 287                 crit_enter();
 288         }
 289         sc->busy = 0;
 290         return(0);
 291 }
 292
 293
 294 static int
 295 mdstrategy_preload(struct dev_strategy_args *ap)
 296 {
 297         cdev_t dev = ap->a_head.a_dev;
 298         struct bio *bio = ap->a_bio;
 299         struct buf *bp = bio->bio_buf;
 300         devstat_trans_flags dop;
 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, bio->bio_offset,
 306                     bp->b_bcount, bp->b_data);
 307
 308         sc = dev->si_drv1;
 309
 310         crit_enter();
 311
 312         bioqdisksort(&sc->bio_queue, bio);
 313
 314         if (sc->busy) {
 315                 crit_exit();
 316                 return(0);
 317         }
 318
 319         sc->busy++;
 320
 321         while (1) {
 322                 bio = bioq_first(&sc->bio_queue);
 323                 if (bio)
 324                         bioq_remove(&sc->bio_queue, bio);
 325                 crit_exit();
 326                 if (bio == NULL)
 327                         break;
 328
 329                 devstat_start_transaction(&sc->stats);
 330
 331                 switch(bp->b_cmd) {
 332                 case BUF_CMD_FREEBLKS:
 333                         dop = DEVSTAT_NO_DATA;
 334                         break;
 335                 case BUF_CMD_READ:
 336                         dop = DEVSTAT_READ;
 337                         bcopy(sc->pl_ptr + bio->bio_offset,
 338                                bp->b_data, bp->b_bcount);
 339                         break;
 340                 case BUF_CMD_WRITE:
 341                         dop = DEVSTAT_WRITE;
 342                         bcopy(bp->b_data, sc->pl_ptr + bio->bio_offset,
 343                               bp->b_bcount);
 344                         break;
 345                 default:
 346                         panic("md: bad cmd %d\n", bp->b_cmd);
 347                 }
 348                 bp->b_resid = 0;
 349                 devstat_end_transaction_buf(&sc->stats, bp);
 350                 biodone(bio);
 351                 crit_enter();
 352         }
 353         sc->busy = 0;
 354         return(0);
 355 }
 356
 357 static struct md_s *
 358 mdcreate(void)
 359 {
 360         struct md_s *sc;
 361
 362         MALLOC(sc, struct md_s *,sizeof(*sc), M_MD, M_WAITOK);
 363         bzero(sc, sizeof(*sc));
 364         sc->unit = mdunits++;
 365         bioq_init(&sc->bio_queue);
 366         devstat_add_entry(&sc->stats, "md", sc->unit, DEV_BSIZE,
 367                 DEVSTAT_NO_ORDERED_TAGS,
 368                 DEVSTAT_TYPE_DIRECT | DEVSTAT_TYPE_IF_OTHER,
 369                 DEVSTAT_PRIORITY_OTHER);
 370         sc->dev = disk_create(sc->unit, &sc->disk, 0, &md_ops);
 371         sc->dev->si_drv1 = sc;
 372         return (sc);
 373 }
 374
 375 static void
 376 mdcreate_preload(u_char *image, unsigned length)
 377 {
 378         struct md_s *sc;
 379
 380         sc = mdcreate();
 381         sc->type = MD_PRELOAD;
 382         sc->nsect = length / DEV_BSIZE;
 383         sc->pl_ptr = image;
 384         sc->pl_len = length;
 385
 386         if (sc->unit == 0)
 387                 mdrootready = 1;
 388 }
 389
 390 static void
 391 mdcreate_malloc(void)
 392 {
 393         struct md_s *sc;
 394
 395         sc = mdcreate();
 396         sc->type = MD_MALLOC;
 397
 398         sc->nsect = MD_NSECT;   /* for now */
 399         MALLOC(sc->secp, u_char **, sizeof(u_char *), M_MD, M_WAITOK);
 400         bzero(sc->secp, sizeof(u_char *));
 401         sc->nsecp = 1;
 402         kprintf("md%d: Malloc disk\n", sc->unit);
 403 }
 404
 405 static void
 406 md_drvinit(void *unused)
 407 {
 408
 409         caddr_t mod;
 410         caddr_t c;
 411         u_char *ptr, *name, *type;
 412         unsigned len;
 413
 414 #ifdef MD_ROOT_SIZE
 415         mdcreate_preload(mfs_root, MD_ROOT_SIZE*1024);
 416 #endif
 417         mod = NULL;
 418         while ((mod = preload_search_next_name(mod)) != NULL) {
 419                 name = (char *)preload_search_info(mod, MODINFO_NAME);
 420                 type = (char *)preload_search_info(mod, MODINFO_TYPE);
 421                 if (name == NULL)
 422                         continue;
 423                 if (type == NULL)
 424                         continue;
 425                 if (strcmp(type, "md_image") && strcmp(type, "mfs_root"))
 426                         continue;
 427                 c = preload_search_info(mod, MODINFO_ADDR);
 428                 ptr = *(u_char **)c;
 429                 c = preload_search_info(mod, MODINFO_SIZE);
 430                 len = *(unsigned *)c;
 431                 kprintf("md%d: Preloaded image <%s> %d bytes at %p\n",
 432                    mdunits, name, len, ptr);
 433                 mdcreate_preload(ptr, len);
 434         }
 435         mdcreate_malloc();
 436 }
 437
 438 SYSINIT(mddev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR, md_drvinit,NULL)
 439
 440 #ifdef MD_ROOT
 441 static void
 442 md_takeroot(void *junk)
 443 {
 444         if (mdrootready)
 445                 rootdevnames[0] = "ufs:/dev/md0c";
 446 }
 447
 448 SYSINIT(md_root, SI_SUB_MOUNT_ROOT, SI_ORDER_FIRST, md_takeroot, NULL);
 449 #endif