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 1.5 2003/07/21 05:50:32 dillon Exp $
  11  *
  12  */
  13
  14 #include "opt_mfs.h"            /* We have adopted some tasks from MFS */
  15 #include "opt_md.h"             /* We have adopted some tasks from MFS */
  16
  17 #include <sys/param.h>
  18 #include <sys/systm.h>
  19 #include <sys/buf.h>
  20 #include <sys/conf.h>
  21 #include <sys/devicestat.h>
  22 #include <sys/disk.h>
  23 #include <sys/kernel.h>
  24 #include <sys/malloc.h>
  25 #include <sys/sysctl.h>
  26 #include <sys/linker.h>
  27 #include <sys/proc.h>
  28 #include <sys/buf2.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(MFS_ROOT) && !defined(MD_ROOT)
  41 #define MD_ROOT MFS_ROOT
  42 #warning "option MFS_ROOT has been superceeded by MD_ROOT"
  43 #endif
  44
  45 #if defined(MFS_ROOT_SIZE) && !defined(MD_ROOT_SIZE)
  46 #define MD_ROOT_SIZE MFS_ROOT_SIZE
  47 #warning "option MFS_ROOT_SIZE has been superceeded by MD_ROOT_SIZE"
  48 #endif
  49
  50 #if defined(MD_ROOT) && defined(MD_ROOT_SIZE)
  51 /* Image gets put here: */
  52 static u_char mfs_root[MD_ROOT_SIZE*1024] = "MFS Filesystem goes here";
  53 static u_char end_mfs_root[] __unused = "MFS Filesystem had better STOP here";
  54 #endif
  55
  56 static int mdrootready;
  57
  58 static void mdcreate_malloc(void);
  59
  60 #define CDEV_MAJOR      95
  61
  62 static d_strategy_t mdstrategy;
  63 static d_strategy_t mdstrategy_preload;
  64 static d_strategy_t mdstrategy_malloc;
  65 static d_open_t mdopen;
  66 static d_ioctl_t mdioctl;
  67
  68 static struct cdevsw md_cdevsw = {
  69         /* name */      "md",
  70         /* maj */       CDEV_MAJOR,
  71         /* flags */     D_DISK | D_CANFREE | D_MEMDISK,
  72         /* port */      NULL,
  73         /* autoq */     0,
  74
  75         /* open */      mdopen,
  76         /* close */     nullclose,
  77         /* read */      physread,
  78         /* write */     physwrite,
  79         /* ioctl */     mdioctl,
  80         /* poll */      nopoll,
  81         /* mmap */      nommap,
  82         /* strategy */  mdstrategy,
  83         /* dump */      nodump,
  84         /* psize */     nopsize,
  85 };
  86
  87 static struct cdevsw mddisk_cdevsw;
  88
  89 struct md_s {
  90         int unit;
  91         struct devstat stats;
  92         struct buf_queue_head buf_queue;
  93         struct disk disk;
  94         dev_t dev;
  95         int busy;
  96         enum {MD_MALLOC, MD_PRELOAD} type;
  97         unsigned nsect;
  98
  99         /* MD_MALLOC related fields */
 100         unsigned nsecp;
 101         u_char **secp;
 102
 103         /* MD_PRELOAD related fields */
 104         u_char *pl_ptr;
 105         unsigned pl_len;
 106 };
 107
 108 static int mdunits;
 109
 110 static int
 111 mdopen(dev_t dev, int flag, int fmt, struct thread *td)
 112 {
 113         struct md_s *sc;
 114         struct disklabel *dl;
 115
 116         if (md_debug)
 117                 printf("mdopen(%s %x %x %p)\n",
 118                         devtoname(dev), flag, fmt, td);
 119
 120         sc = dev->si_drv1;
 121         if (sc->unit + 1 == mdunits)
 122                 mdcreate_malloc();
 123
 124         dl = &sc->disk.d_label;
 125         bzero(dl, sizeof(*dl));
 126         dl->d_secsize = DEV_BSIZE;
 127         dl->d_nsectors = 1024;
 128         dl->d_ntracks = 1;
 129         dl->d_secpercyl = dl->d_nsectors * dl->d_ntracks;
 130         dl->d_secperunit = sc->nsect;
 131         dl->d_ncylinders = dl->d_secperunit / dl->d_secpercyl;
 132         return (0);
 133 }
 134
 135 static int
 136 mdioctl(dev_t dev, u_long cmd, caddr_t addr, int flags, struct thread *td)
 137 {
 138
 139         if (md_debug)
 140                 printf("mdioctl(%s %lx %p %x %p)\n",
 141                         devtoname(dev), cmd, addr, flags, td);
 142
 143         return (ENOIOCTL);
 144 }
 145
 146 static void
 147 mdstrategy(struct buf *bp)
 148 {
 149         struct md_s *sc;
 150
 151         if (md_debug > 1)
 152                 printf("mdstrategy(%p) %s %lx, %d, %ld, %p)\n",
 153                     bp, devtoname(bp->b_dev), bp->b_flags, bp->b_blkno,
 154                     bp->b_bcount / DEV_BSIZE, bp->b_data);
 155
 156         sc = bp->b_dev->si_drv1;
 157         if (sc->type == MD_MALLOC) {
 158                 mdstrategy_malloc(bp);
 159         } else {
 160                 mdstrategy_preload(bp);
 161         }
 162         return;
 163 }
 164
 165
 166 static void
 167 mdstrategy_malloc(struct buf *bp)
 168 {
 169         int s, i;
 170         struct md_s *sc;
 171         devstat_trans_flags dop;
 172         u_char *secp, **secpp, *dst;
 173         unsigned secno, nsec, secval, uc;
 174
 175         if (md_debug > 1)
 176                 printf("mdstrategy_malloc(%p) %s %lx, %d, %ld, %p)\n",
 177                     bp, devtoname(bp->b_dev), bp->b_flags, bp->b_blkno,
 178                     bp->b_bcount / DEV_BSIZE, bp->b_data);
 179
 180         sc = bp->b_dev->si_drv1;
 181
 182         s = splbio();
 183
 184         bufqdisksort(&sc->buf_queue, bp);
 185
 186         if (sc->busy) {
 187                 splx(s);
 188                 return;
 189         }
 190
 191         sc->busy++;
 192
 193         while (1) {
 194                 bp = bufq_first(&sc->buf_queue);
 195                 if (bp)
 196                         bufq_remove(&sc->buf_queue, bp);
 197                 splx(s);
 198                 if (!bp)
 199                         break;
 200
 201                 devstat_start_transaction(&sc->stats);
 202
 203                 if (bp->b_flags & B_FREEBUF)
 204                         dop = DEVSTAT_NO_DATA;
 205                 else if (bp->b_flags & B_READ)
 206                         dop = DEVSTAT_READ;
 207                 else
 208                         dop = DEVSTAT_WRITE;
 209
 210                 nsec = bp->b_bcount / DEV_BSIZE;
 211                 secno = bp->b_pblkno;
 212                 dst = bp->b_data;
 213                 while (nsec--) {
 214
 215                         if (secno < sc->nsecp) {
 216                                 secpp = &sc->secp[secno];
 217                                 if ((u_int)*secpp > 255) {
 218                                         secp = *secpp;
 219                                         secval = 0;
 220                                 } else {
 221                                         secp = 0;
 222                                         secval = (u_int) *secpp;
 223                                 }
 224                         } else {
 225                                 secpp = 0;
 226                                 secp = 0;
 227                                 secval = 0;
 228                         }
 229                         if (md_debug > 2)
 230                                 printf("%lx %p %p %d\n", bp->b_flags, secpp, secp, secval);
 231
 232                         if (bp->b_flags & B_FREEBUF) {
 233                                 if (secpp) {
 234                                         if (secp)
 235                                                 FREE(secp, M_MDSECT);
 236                                         *secpp = 0;
 237                                 }
 238                         } else if (bp->b_flags & B_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                         } else {
 248                                 uc = dst[0];
 249                                 for (i = 1; i < DEV_BSIZE; i++)
 250                                         if (dst[i] != uc)
 251                                                 break;
 252                                 if (i == DEV_BSIZE && !uc) {
 253                                         if (secp)
 254                                                 FREE(secp, M_MDSECT);
 255                                         if (secpp)
 256                                                 *secpp = (u_char *)uc;
 257                                 } else {
 258                                         if (!secpp) {
 259                                                 MALLOC(secpp, u_char **, (secno + nsec + 1) * sizeof(u_char *), M_MD, M_WAITOK);
 260                                                 bzero(secpp, (secno + nsec + 1) * sizeof(u_char *));
 261                                                 bcopy(sc->secp, secpp, sc->nsecp * sizeof(u_char *));
 262                                                 FREE(sc->secp, M_MD);
 263                                                 sc->secp = secpp;
 264                                                 sc->nsecp = secno + nsec + 1;
 265                                                 secpp = &sc->secp[secno];
 266                                         }
 267                                         if (i == DEV_BSIZE) {
 268                                                 if (secp)
 269                                                         FREE(secp, M_MDSECT);
 270                                                 *secpp = (u_char *)uc;
 271                                         } else {
 272                                                 if (!secp)
 273                                                         MALLOC(secp, u_char *, DEV_BSIZE, M_MDSECT, M_WAITOK);
 274                                                 bcopy(dst, secp, DEV_BSIZE);
 275
 276                                                 *secpp = secp;
 277                                         }
 278                                 }
 279                         }
 280                         secno++;
 281                         dst += DEV_BSIZE;
 282                 }
 283                 bp->b_resid = 0;
 284                 devstat_end_transaction_buf(&sc->stats, bp);
 285                 biodone(bp);
 286                 s = splbio();
 287         }
 288         sc->busy = 0;
 289         return;
 290 }
 291
 292
 293 static void
 294 mdstrategy_preload(struct buf *bp)
 295 {
 296         int s;
 297         struct md_s *sc;
 298         devstat_trans_flags dop;
 299
 300         if (md_debug > 1)
 301                 printf("mdstrategy_preload(%p) %s %lx, %d, %ld, %p)\n",
 302                     bp, devtoname(bp->b_dev), bp->b_flags, bp->b_blkno,
 303                     bp->b_bcount / DEV_BSIZE, bp->b_data);
 304
 305         sc = bp->b_dev->si_drv1;
 306
 307         s = splbio();
 308
 309         bufqdisksort(&sc->buf_queue, bp);
 310
 311         if (sc->busy) {
 312                 splx(s);
 313                 return;
 314         }
 315
 316         sc->busy++;
 317
 318         while (1) {
 319                 bp = bufq_first(&sc->buf_queue);
 320                 if (bp)
 321                         bufq_remove(&sc->buf_queue, bp);
 322                 splx(s);
 323                 if (!bp)
 324                         break;
 325
 326                 devstat_start_transaction(&sc->stats);
 327
 328                 if (bp->b_flags & B_FREEBUF) {
 329                         dop = DEVSTAT_NO_DATA;
 330                 } else if (bp->b_flags & B_READ) {
 331                         dop = DEVSTAT_READ;
 332                         bcopy(sc->pl_ptr + (bp->b_pblkno << DEV_BSHIFT), bp->b_data, bp->b_bcount);
 333                 } else {
 334                         dop = DEVSTAT_WRITE;
 335                         bcopy(bp->b_data, sc->pl_ptr + (bp->b_pblkno << DEV_BSHIFT), bp->b_bcount);
 336                 }
 337                 bp->b_resid = 0;
 338                 devstat_end_transaction_buf(&sc->stats, bp);
 339                 biodone(bp);
 340                 s = splbio();
 341         }
 342         sc->busy = 0;
 343         return;
 344 }
 345
 346 static struct md_s *
 347 mdcreate(void)
 348 {
 349         struct md_s *sc;
 350
 351         MALLOC(sc, struct md_s *,sizeof(*sc), M_MD, M_WAITOK);
 352         bzero(sc, sizeof(*sc));
 353         sc->unit = mdunits++;
 354         bufq_init(&sc->buf_queue);
 355         devstat_add_entry(&sc->stats, "md", sc->unit, DEV_BSIZE,
 356                 DEVSTAT_NO_ORDERED_TAGS,
 357                 DEVSTAT_TYPE_DIRECT | DEVSTAT_TYPE_IF_OTHER,
 358                 DEVSTAT_PRIORITY_OTHER);
 359         sc->dev = disk_create(sc->unit, &sc->disk, 0, &md_cdevsw, &mddisk_cdevsw);
 360         sc->dev->si_drv1 = sc;
 361         return (sc);
 362 }
 363
 364 static void
 365 mdcreate_preload(u_char *image, unsigned length)
 366 {
 367         struct md_s *sc;
 368
 369         sc = mdcreate();
 370         sc->type = MD_PRELOAD;
 371         sc->nsect = length / DEV_BSIZE;
 372         sc->pl_ptr = image;
 373         sc->pl_len = length;
 374
 375         if (sc->unit == 0)
 376                 mdrootready = 1;
 377 }
 378
 379 static void
 380 mdcreate_malloc(void)
 381 {
 382         struct md_s *sc;
 383
 384         sc = mdcreate();
 385         sc->type = MD_MALLOC;
 386
 387         sc->nsect = MD_NSECT;   /* for now */
 388         MALLOC(sc->secp, u_char **, sizeof(u_char *), M_MD, M_WAITOK);
 389         bzero(sc->secp, sizeof(u_char *));
 390         sc->nsecp = 1;
 391         printf("md%d: Malloc disk\n", sc->unit);
 392 }
 393
 394 static void
 395 md_drvinit(void *unused)
 396 {
 397
 398         caddr_t mod;
 399         caddr_t c;
 400         u_char *ptr, *name, *type;
 401         unsigned len;
 402
 403 #ifdef MD_ROOT_SIZE
 404         mdcreate_preload(mfs_root, MD_ROOT_SIZE*1024);
 405 #endif
 406         mod = NULL;
 407         while ((mod = preload_search_next_name(mod)) != NULL) {
 408                 name = (char *)preload_search_info(mod, MODINFO_NAME);
 409                 type = (char *)preload_search_info(mod, MODINFO_TYPE);
 410                 if (name == NULL)
 411                         continue;
 412                 if (type == NULL)
 413                         continue;
 414                 if (strcmp(type, "md_image") && strcmp(type, "mfs_root"))
 415                         continue;
 416                 c = preload_search_info(mod, MODINFO_ADDR);
 417                 ptr = *(u_char **)c;
 418                 c = preload_search_info(mod, MODINFO_SIZE);
 419                 len = *(unsigned *)c;
 420                 printf("md%d: Preloaded image <%s> %d bytes at %p\n",
 421                    mdunits, name, len, ptr);
 422                 mdcreate_preload(ptr, len);
 423         }
 424         mdcreate_malloc();
 425 }
 426
 427 SYSINIT(mddev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR, md_drvinit,NULL)
 428
 429 #ifdef MD_ROOT
 430 static void
 431 md_takeroot(void *junk)
 432 {
 433         if (mdrootready)
 434                 rootdevnames[0] = "ufs:/dev/md0c";
 435 }
 436
 437 SYSINIT(md_root, SI_SUB_MOUNT_ROOT, SI_ORDER_FIRST, md_takeroot, NULL);
 438 #endif