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,
 140                     (long long)bio->bio_offset,
 141                     bp->b_bcount, bp->b_data);
 142         }
 143         bio->bio_driver_info = dev;
 144         sc = dev->si_drv1;
 145         if (sc->type == MD_MALLOC) {
 146                 mdstrategy_malloc(ap);
 147         } else {
 148                 mdstrategy_preload(ap);
 149         }
 150         return(0);
 151 }
 152
 153
 154 static int
 155 mdstrategy_malloc(struct dev_strategy_args *ap)
 156 {
 157         cdev_t dev = ap->a_head.a_dev;
 158         struct bio *bio = ap->a_bio;
 159         struct buf *bp = bio->bio_buf;
 160         unsigned secno, nsec, secval, uc;
 161         u_char *secp, **secpp, *dst;
 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,
 168                     (long long)bio->bio_offset,
 169                     bp->b_bcount, bp->b_data);
 170
 171         sc = dev->si_drv1;
 172
 173         crit_enter();
 174
 175         bioqdisksort(&sc->bio_queue, bio);
 176
 177         if (sc->busy) {
 178                 crit_exit();
 179                 return(0);
 180         }
 181
 182         sc->busy++;
 183
 184         while (1) {
 185                 bio = bioq_first(&sc->bio_queue);
 186                 if (bio == NULL) {
 187                         crit_exit();
 188                         break;
 189                 }
 190                 crit_exit();
 191                 bioq_remove(&sc->bio_queue, bio);
 192                 bp = bio->bio_buf;
 193
 194                 devstat_start_transaction(&sc->stats);
 195
 196                 switch (bp->b_cmd) {
 197                 case BUF_CMD_FREEBLKS:
 198                 case BUF_CMD_READ:
 199                 case BUF_CMD_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)(uintptr_t)*secpp > 255) {
 212                                         secp = *secpp;
 213                                         secval = 0;
 214                                 } else {
 215                                         secp = 0;
 216                                         secval = (u_int)(uintptr_t)*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 *)(uintptr_t)uc;
 254                                 } else {
 255                                         if (!secpp) {
 256                                                 MALLOC(secpp, u_char **, (secno + nsec + 1) * sizeof(u_char *), M_MD, M_WAITOK | M_ZERO);
 257                                                 bcopy(sc->secp, secpp, sc->nsecp * sizeof(u_char *));
 258                                                 FREE(sc->secp, M_MD);
 259                                                 sc->secp = secpp;
 260                                                 sc->nsecp = secno + nsec + 1;
 261                                                 secpp = &sc->secp[secno];
 262                                         }
 263                                         if (i == DEV_BSIZE) {
 264                                                 if (secp)
 265                                                         FREE(secp, M_MDSECT);
 266                                                 *secpp = (u_char *)(uintptr_t)uc;
 267                                         } else {
 268                                                 if (!secp)
 269                                                         MALLOC(secp, u_char *, DEV_BSIZE, M_MDSECT, M_WAITOK);
 270                                                 bcopy(dst, secp, DEV_BSIZE);
 271
 272                                                 *secpp = secp;
 273                                         }
 274                                 }
 275                                 break;
 276                         default:
 277                                 panic("md: bad b_cmd %d", bp->b_cmd);
 278
 279                         }
 280                         secno++;
 281                         dst += DEV_BSIZE;
 282                 }
 283                 bp->b_resid = 0;
 284                 devstat_end_transaction_buf(&sc->stats, bp);
 285                 biodone(bio);
 286                 crit_enter();
 287         }
 288         sc->busy = 0;
 289         return(0);
 290 }
 291
 292
 293 static int
 294 mdstrategy_preload(struct dev_strategy_args *ap)
 295 {
 296         cdev_t dev = ap->a_head.a_dev;
 297         struct bio *bio = ap->a_bio;
 298         struct buf *bp = bio->bio_buf;
 299         struct md_s *sc;
 300
 301         if (md_debug > 1)
 302                 kprintf("mdstrategy_preload(%p) %s %08x, %lld, %d, %p)\n",
 303                     bp, devtoname(dev), bp->b_flags,
 304                     (long long)bio->bio_offset,
 305                     bp->b_bcount, bp->b_data);
 306
 307         sc = dev->si_drv1;
 308
 309         crit_enter();
 310
 311         bioqdisksort(&sc->bio_queue, bio);
 312
 313         if (sc->busy) {
 314                 crit_exit();
 315                 return(0);
 316         }
 317
 318         sc->busy++;
 319
 320         while (1) {
 321                 bio = bioq_first(&sc->bio_queue);
 322                 if (bio)
 323                         bioq_remove(&sc->bio_queue, bio);
 324                 crit_exit();
 325                 if (bio == NULL)
 326                         break;
 327
 328                 devstat_start_transaction(&sc->stats);
 329
 330                 switch (bp->b_cmd) {
 331                 case BUF_CMD_FREEBLKS:
 332                         break;
 333                 case BUF_CMD_READ:
 334                         bcopy(sc->pl_ptr + bio->bio_offset,
 335                                bp->b_data, bp->b_bcount);
 336                         break;
 337                 case BUF_CMD_WRITE:
 338                         bcopy(bp->b_data, sc->pl_ptr + bio->bio_offset,
 339                               bp->b_bcount);
 340                         break;
 341                 default:
 342                         panic("md: bad cmd %d\n", bp->b_cmd);
 343                 }
 344                 bp->b_resid = 0;
 345                 devstat_end_transaction_buf(&sc->stats, bp);
 346                 biodone(bio);
 347                 crit_enter();
 348         }
 349         sc->busy = 0;
 350         return(0);
 351 }
 352
 353 static struct md_s *
 354 mdcreate(void)
 355 {
 356         struct md_s *sc;
 357
 358         MALLOC(sc, struct md_s *,sizeof(*sc), M_MD, M_WAITOK | M_ZERO);
 359         sc->unit = mdunits++;
 360         bioq_init(&sc->bio_queue);
 361         devstat_add_entry(&sc->stats, "md", sc->unit, DEV_BSIZE,
 362                 DEVSTAT_NO_ORDERED_TAGS,
 363                 DEVSTAT_TYPE_DIRECT | DEVSTAT_TYPE_IF_OTHER,
 364                 DEVSTAT_PRIORITY_OTHER);
 365         sc->dev = disk_create(sc->unit, &sc->disk, &md_ops);
 366         sc->dev->si_drv1 = sc;
 367         sc->dev->si_iosize_max = DFLTPHYS;
 368
 369         return (sc);
 370 }
 371
 372 static void
 373 mdcreate_preload(u_char *image, unsigned length)
 374 {
 375         struct md_s *sc;
 376
 377         sc = mdcreate();
 378         sc->type = MD_PRELOAD;
 379         sc->nsect = length / DEV_BSIZE;
 380         sc->pl_ptr = image;
 381         sc->pl_len = length;
 382
 383         if (sc->unit == 0)
 384                 mdrootready = 1;
 385 }
 386
 387 static void
 388 mdcreate_malloc(void)
 389 {
 390         struct md_s *sc;
 391
 392         sc = mdcreate();
 393         sc->type = MD_MALLOC;
 394
 395         sc->nsect = MD_NSECT;   /* for now */
 396         MALLOC(sc->secp, u_char **, sizeof(u_char *), M_MD, M_WAITOK | M_ZERO);
 397         sc->nsecp = 1;
 398         kprintf("md%d: Malloc disk\n", sc->unit);
 399 }
 400
 401 static void
 402 md_drvinit(void *unused)
 403 {
 404
 405         caddr_t mod;
 406         caddr_t c;
 407         u_char *ptr, *name, *type;
 408         unsigned len;
 409
 410 #ifdef MD_ROOT_SIZE
 411         mdcreate_preload(mfs_root, MD_ROOT_SIZE*1024);
 412 #endif
 413         mod = NULL;
 414         while ((mod = preload_search_next_name(mod)) != NULL) {
 415                 name = (char *)preload_search_info(mod, MODINFO_NAME);
 416                 type = (char *)preload_search_info(mod, MODINFO_TYPE);
 417                 if (name == NULL)
 418                         continue;
 419                 if (type == NULL)
 420                         continue;
 421                 if (strcmp(type, "md_image") && strcmp(type, "mfs_root"))
 422                         continue;
 423                 c = preload_search_info(mod, MODINFO_ADDR);
 424                 ptr = *(u_char **)c;
 425                 c = preload_search_info(mod, MODINFO_SIZE);
 426                 len = *(unsigned *)c;
 427                 kprintf("md%d: Preloaded image <%s> %d bytes at %p\n",
 428                    mdunits, name, len, ptr);
 429                 mdcreate_preload(ptr, len);
 430         }
 431         mdcreate_malloc();
 432 }
 433
 434 SYSINIT(mddev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR, md_drvinit,NULL)
 435
 436 #ifdef MD_ROOT
 437 static void
 438 md_takeroot(void *junk)
 439 {
 440         if (mdrootready)
 441                 rootdevnames[0] = "ufs:/dev/md0c";
 442 }
 443
 444 SYSINIT(md_root, SI_SUB_MOUNT_ROOT, SI_ORDER_FIRST, md_takeroot, NULL);
 445 #endif