md.c revision 1.78.6.2
1 /* $NetBSD: md.c,v 1.78.6.2 2017/04/27 23:18:21 pgoyette Exp $ */ 2 3 /* 4 * Copyright (c) 1995 Gordon W. Ross, Leo Weppelman. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 */ 27 28 /* 29 * This implements a general-purpose memory-disk. 30 * See md.h for notes on the config types. 31 * 32 * Note that this driver provides the same functionality 33 * as the MFS filesystem hack, but this is better because 34 * you can use this for any filesystem type you'd like! 35 * 36 * Credit for most of the kmem ramdisk code goes to: 37 * Leo Weppelman (atari) and Phil Nelson (pc532) 38 * Credit for the ideas behind the "user space memory" code goes 39 * to the authors of the MFS implementation. 40 */ 41 42 #include <sys/cdefs.h> 43 __KERNEL_RCSID(0, "$NetBSD: md.c,v 1.78.6.2 2017/04/27 23:18:21 pgoyette Exp $"); 44 45 #ifdef _KERNEL_OPT 46 #include "opt_md.h" 47 #else 48 #define MEMORY_DISK_SERVER 1 49 #endif 50 51 #include <sys/param.h> 52 #include <sys/kernel.h> 53 #include <sys/malloc.h> 54 #include <sys/systm.h> 55 #include <sys/buf.h> 56 #include <sys/bufq.h> 57 #include <sys/device.h> 58 #include <sys/disk.h> 59 #include <sys/stat.h> 60 #include <sys/proc.h> 61 #include <sys/conf.h> 62 #include <sys/disklabel.h> 63 #include <sys/localcount.h> 64 65 #include <uvm/uvm_extern.h> 66 67 #include <dev/md.h> 68 69 #include "ioconf.h" 70 /* 71 * The user-space functionality is included by default. 72 * Use `options MEMORY_DISK_SERVER=0' to turn it off. 73 */ 74 #ifndef MEMORY_DISK_SERVER 75 #error MEMORY_DISK_SERVER should be defined by opt_md.h 76 #endif /* MEMORY_DISK_SERVER */ 77 78 /* 79 * We should use the raw partition for ioctl. 80 */ 81 #define MD_UNIT(unit) DISKUNIT(unit) 82 83 /* autoconfig stuff... */ 84 85 struct md_softc { 86 device_t sc_dev; /* Self. */ 87 struct disk sc_dkdev; /* hook for generic disk handling */ 88 struct md_conf sc_md; 89 kmutex_t sc_lock; /* Protect self. */ 90 kcondvar_t sc_cv; /* Wait here for work. */ 91 struct bufq_state *sc_buflist; 92 }; 93 /* shorthand for fields in sc_md: */ 94 #define sc_addr sc_md.md_addr 95 #define sc_size sc_md.md_size 96 #define sc_type sc_md.md_type 97 98 static void md_attach(device_t, device_t, void *); 99 static int md_detach(device_t, int); 100 101 static dev_type_open(mdopen); 102 static dev_type_close(mdclose); 103 static dev_type_read(mdread); 104 static dev_type_write(mdwrite); 105 static dev_type_ioctl(mdioctl); 106 static dev_type_strategy(mdstrategy); 107 static dev_type_size(mdsize); 108 109 const struct bdevsw md_bdevsw = { 110 DEVSW_MODULE_INIT 111 .d_open = mdopen, 112 .d_close = mdclose, 113 .d_strategy = mdstrategy, 114 .d_ioctl = mdioctl, 115 .d_dump = nodump, 116 .d_psize = mdsize, 117 .d_discard = nodiscard, 118 .d_flag = D_DISK | D_MPSAFE 119 }; 120 121 const struct cdevsw md_cdevsw = { 122 DEVSW_MODULE_INIT 123 .d_open = mdopen, 124 .d_close = mdclose, 125 .d_read = mdread, 126 .d_write = mdwrite, 127 .d_ioctl = mdioctl, 128 .d_stop = nostop, 129 .d_tty = notty, 130 .d_poll = nopoll, 131 .d_mmap = nommap, 132 .d_kqfilter = nokqfilter, 133 .d_discard = nodiscard, 134 .d_flag = D_DISK 135 }; 136 137 static struct dkdriver mddkdriver = { 138 .d_strategy = mdstrategy 139 }; 140 141 extern struct cfdriver md_cd; 142 CFATTACH_DECL3_NEW(md, sizeof(struct md_softc), 143 0, md_attach, md_detach, NULL, NULL, NULL, DVF_DETACH_SHUTDOWN); 144 145 static kmutex_t md_device_lock; /* Protect unit creation / deletion. */ 146 extern size_t md_root_size; 147 148 static void md_set_disklabel(struct md_softc *); 149 150 /* 151 * This is called if we are configured as a pseudo-device 152 */ 153 void 154 mdattach(int n) 155 { 156 157 mutex_init(&md_device_lock, MUTEX_DEFAULT, IPL_NONE); 158 if (config_cfattach_attach(md_cd.cd_name, &md_ca)) { 159 aprint_error("%s: cfattach_attach failed\n", md_cd.cd_name); 160 return; 161 } 162 } 163 164 static void 165 md_attach(device_t parent, device_t self, void *aux) 166 { 167 struct md_softc *sc = device_private(self); 168 169 sc->sc_dev = self; 170 sc->sc_type = MD_UNCONFIGURED; 171 mutex_init(&sc->sc_lock, MUTEX_DEFAULT, IPL_NONE); 172 cv_init(&sc->sc_cv, "mdidle"); 173 bufq_alloc(&sc->sc_buflist, "fcfs", 0); 174 175 /* XXX - Could accept aux info here to set the config. */ 176 #ifdef MEMORY_DISK_HOOKS 177 /* 178 * This external function might setup a pre-loaded disk. 179 * All it would need to do is setup the md_conf struct. 180 * See sys/dev/md_root.c for an example. 181 */ 182 md_attach_hook(device_unit(self), &sc->sc_md); 183 #endif 184 185 /* 186 * Initialize and attach the disk structure. 187 */ 188 disk_init(&sc->sc_dkdev, device_xname(self), &mddkdriver); 189 disk_attach(&sc->sc_dkdev); 190 191 if (sc->sc_type != MD_UNCONFIGURED) 192 md_set_disklabel(sc); 193 194 if (!pmf_device_register(self, NULL, NULL)) 195 aprint_error_dev(self, "couldn't establish power handler\n"); 196 } 197 198 /* 199 * Caller must hold a reference to the device's localcount. The reference 200 * is released if detach is successful. 201 */ 202 static int 203 md_detach(device_t self, int flags) 204 { 205 struct md_softc *sc = device_private(self); 206 int rc; 207 208 rc = 0; 209 mutex_enter(&sc->sc_dkdev.dk_openlock); 210 if (sc->sc_dkdev.dk_openmask == 0 && sc->sc_type == MD_UNCONFIGURED) 211 ; /* nothing to do */ 212 else if ((flags & DETACH_FORCE) == 0) 213 rc = EBUSY; 214 mutex_exit(&sc->sc_dkdev.dk_openlock); 215 216 if (rc != 0) 217 return rc; 218 219 device_release(self); 220 pmf_device_deregister(self); 221 disk_detach(&sc->sc_dkdev); 222 disk_destroy(&sc->sc_dkdev); 223 bufq_free(sc->sc_buflist); 224 mutex_destroy(&sc->sc_lock); 225 cv_destroy(&sc->sc_cv); 226 return 0; 227 } 228 229 /* 230 * operational routines: 231 * open, close, read, write, strategy, 232 * ioctl, dump, size 233 */ 234 235 #if MEMORY_DISK_SERVER 236 static int md_server_loop(struct md_softc *sc); 237 static int md_ioctl_server(struct md_softc *sc, struct md_conf *umd, 238 struct lwp *l); 239 #endif /* MEMORY_DISK_SERVER */ 240 static int md_ioctl_kalloc(struct md_softc *sc, struct md_conf *umd, 241 struct lwp *l); 242 243 static int 244 mdsize(dev_t dev) 245 { 246 struct md_softc *sc; 247 int res; 248 249 sc = device_lookup_private_acquire(&md_cd, MD_UNIT(dev)); 250 if (sc == NULL) 251 return 0; 252 253 mutex_enter(&sc->sc_lock); 254 if (sc->sc_type == MD_UNCONFIGURED) 255 res = 0; 256 else 257 res = sc->sc_size >> DEV_BSHIFT; 258 mutex_exit(&sc->sc_lock); 259 260 device_release(sc->sc_dev); 261 return res; 262 } 263 264 static int 265 mdopen(dev_t dev, int flag, int fmt, struct lwp *l) 266 { 267 device_t self, new_self; 268 int unit; 269 int part = DISKPART(dev); 270 int pmask = 1 << part; 271 cfdata_t cf; 272 struct md_softc *sc; 273 struct disk *dk; 274 #ifdef MEMORY_DISK_HOOKS 275 bool configured; 276 #endif 277 278 mutex_enter(&md_device_lock); 279 unit = MD_UNIT(dev); 280 sc = device_lookup_private_acquire(&md_cd, unit); 281 if (sc == NULL) { 282 if (part != RAW_PART) { 283 mutex_exit(&md_device_lock); 284 return ENXIO; 285 } 286 cf = malloc(sizeof(*cf), M_DEVBUF, M_WAITOK); 287 cf->cf_name = md_cd.cd_name; 288 cf->cf_atname = md_cd.cd_name; 289 cf->cf_unit = unit; 290 cf->cf_fstate = FSTATE_STAR; 291 new_self = config_attach_pseudo(cf); 292 self = device_lookup_acquire(&md_cd, unit); 293 KASSERT(self == new_self); 294 sc = device_private(self); 295 if (sc == NULL) { 296 mutex_exit(&md_device_lock); 297 device_release(self); 298 return ENOMEM; 299 } 300 } 301 302 dk = &sc->sc_dkdev; 303 304 /* 305 * The raw partition is used for ioctl to configure. 306 */ 307 if (part == RAW_PART) 308 goto ok; 309 310 #ifdef MEMORY_DISK_HOOKS 311 /* Call the open hook to allow loading the device. */ 312 configured = (sc->sc_type != MD_UNCONFIGURED); 313 md_open_hook(unit, &sc->sc_md); 314 /* initialize disklabel if the device is configured in open hook */ 315 if (!configured && sc->sc_type != MD_UNCONFIGURED) 316 md_set_disklabel(sc); 317 #endif 318 319 /* 320 * This is a normal, "slave" device, so 321 * enforce initialized. 322 */ 323 if (sc->sc_type == MD_UNCONFIGURED) { 324 mutex_exit(&md_device_lock); 325 device_release(sc->sc_dev); 326 return ENXIO; 327 } 328 329 ok: 330 /* XXX duplicates code in dk_open(). Call dk_open(), instead? */ 331 mutex_enter(&dk->dk_openlock); 332 /* Mark our unit as open. */ 333 switch (fmt) { 334 case S_IFCHR: 335 dk->dk_copenmask |= pmask; 336 break; 337 case S_IFBLK: 338 dk->dk_bopenmask |= pmask; 339 break; 340 } 341 342 dk->dk_openmask = dk->dk_copenmask | dk->dk_bopenmask; 343 344 mutex_exit(&dk->dk_openlock); 345 mutex_exit(&md_device_lock); 346 device_release(sc->sc_dev); 347 return 0; 348 } 349 350 static int 351 mdclose(dev_t dev, int flag, int fmt, struct lwp *l) 352 { 353 int part = DISKPART(dev); 354 int pmask = 1 << part; 355 int error; 356 cfdata_t cf; 357 struct md_softc *sc; 358 struct disk *dk; 359 360 sc = device_lookup_private_acquire(&md_cd, MD_UNIT(dev)); 361 if (sc == NULL) 362 return ENXIO; 363 364 dk = &sc->sc_dkdev; 365 366 mutex_enter(&dk->dk_openlock); 367 368 switch (fmt) { 369 case S_IFCHR: 370 dk->dk_copenmask &= ~pmask; 371 break; 372 case S_IFBLK: 373 dk->dk_bopenmask &= ~pmask; 374 break; 375 } 376 dk->dk_openmask = dk->dk_copenmask | dk->dk_bopenmask; 377 if (dk->dk_openmask != 0) { 378 mutex_exit(&dk->dk_openlock); 379 device_release(sc->sc_dev); 380 return 0; 381 } 382 383 mutex_exit(&dk->dk_openlock); 384 385 mutex_enter(&md_device_lock); 386 cf = device_cfdata(sc->sc_dev); 387 error = config_detach(sc->sc_dev, DETACH_QUIET); 388 if (! error) 389 free(cf, M_DEVBUF); 390 mutex_exit(&md_device_lock); 391 if (error) 392 device_release(sc->sc_dev); 393 return error; 394 } 395 396 static int 397 mdread(dev_t dev, struct uio *uio, int flags) 398 { 399 struct md_softc *sc; 400 int error; 401 402 sc = device_lookup_private_acquire(&md_cd, MD_UNIT(dev)); 403 404 if (sc == NULL || sc->sc_type == MD_UNCONFIGURED) { 405 if (sc != NULL) 406 device_release(sc->sc_dev); 407 return ENXIO; 408 } 409 410 error = (physio(mdstrategy, NULL, dev, B_READ, minphys, uio)); 411 device_release(sc->sc_dev); 412 return error; 413 } 414 415 static int 416 mdwrite(dev_t dev, struct uio *uio, int flags) 417 { 418 struct md_softc *sc; 419 int error; 420 421 sc = device_lookup_private_acquire(&md_cd, MD_UNIT(dev)); 422 423 if (sc == NULL || sc->sc_type == MD_UNCONFIGURED) { 424 if (sc != NULL) { 425 device_release(sc->sc_dev); 426 } 427 return ENXIO; 428 } 429 430 error = physio(mdstrategy, NULL, dev, B_WRITE, minphys, uio); 431 432 device_release(sc->sc_dev); 433 return error; 434 } 435 436 /* 437 * Handle I/O requests, either directly, or 438 * by passing them to the server process. 439 */ 440 static void 441 mdstrategy(struct buf *bp) 442 { 443 struct md_softc *sc; 444 void * addr; 445 size_t off, xfer; 446 bool is_read; 447 448 sc = device_lookup_private_acquire(&md_cd, MD_UNIT(bp->b_dev)); 449 if (sc == NULL || sc->sc_type == MD_UNCONFIGURED) { 450 bp->b_error = ENXIO; 451 goto done; 452 } 453 454 mutex_enter(&sc->sc_lock); 455 456 switch (sc->sc_type) { 457 #if MEMORY_DISK_SERVER 458 case MD_UMEM_SERVER: 459 /* Just add this job to the server's queue. */ 460 bufq_put(sc->sc_buflist, bp); 461 cv_signal(&sc->sc_cv); 462 mutex_exit(&sc->sc_lock); 463 /* see md_server_loop() */ 464 /* no biodone in this case */ 465 device_release(sc->sc_dev); 466 return; 467 #endif /* MEMORY_DISK_SERVER */ 468 469 case MD_KMEM_FIXED: 470 case MD_KMEM_ALLOCATED: 471 /* These are in kernel space. Access directly. */ 472 is_read = ((bp->b_flags & B_READ) == B_READ); 473 bp->b_resid = bp->b_bcount; 474 off = (bp->b_blkno << DEV_BSHIFT); 475 if (off >= sc->sc_size) { 476 if (is_read) 477 break; /* EOF */ 478 goto set_eio; 479 } 480 xfer = bp->b_resid; 481 if (xfer > (sc->sc_size - off)) 482 xfer = (sc->sc_size - off); 483 addr = (char *)sc->sc_addr + off; 484 disk_busy(&sc->sc_dkdev); 485 if (is_read) 486 memcpy(bp->b_data, addr, xfer); 487 else 488 memcpy(addr, bp->b_data, xfer); 489 disk_unbusy(&sc->sc_dkdev, xfer, is_read); 490 bp->b_resid -= xfer; 491 break; 492 493 default: 494 bp->b_resid = bp->b_bcount; 495 set_eio: 496 bp->b_error = EIO; 497 break; 498 } 499 mutex_exit(&sc->sc_lock); 500 501 done: 502 biodone(bp); 503 if (sc != NULL) 504 device_release(sc->sc_dev); 505 } 506 507 static int 508 mdioctl(dev_t dev, u_long cmd, void *data, int flag, struct lwp *l) 509 { 510 struct md_softc *sc; 511 struct md_conf *umd; 512 int error; 513 514 sc = device_lookup_private_acquire(&md_cd, MD_UNIT(dev)); 515 if (sc == NULL) 516 return ENXIO; 517 518 mutex_enter(&sc->sc_lock); 519 if (sc->sc_type != MD_UNCONFIGURED) { 520 error = disk_ioctl(&sc->sc_dkdev, dev, cmd, data, flag, l); 521 if (error != EPASSTHROUGH) { 522 mutex_exit(&sc->sc_lock); 523 device_release(sc->sc_dev); 524 return 0; 525 } 526 } 527 528 /* If this is not the raw partition, punt! */ 529 if (DISKPART(dev) != RAW_PART) { 530 mutex_exit(&sc->sc_lock); 531 device_release(sc->sc_dev); 532 return ENOTTY; 533 } 534 535 umd = (struct md_conf *)data; 536 error = EINVAL; 537 switch (cmd) { 538 case MD_GETCONF: 539 *umd = sc->sc_md; 540 error = 0; 541 break; 542 543 case MD_SETCONF: 544 /* Can only set it once. */ 545 if (sc->sc_type != MD_UNCONFIGURED) 546 break; 547 switch (umd->md_type) { 548 case MD_KMEM_ALLOCATED: 549 error = md_ioctl_kalloc(sc, umd, l); 550 break; 551 #if MEMORY_DISK_SERVER 552 case MD_UMEM_SERVER: 553 error = md_ioctl_server(sc, umd, l); 554 break; 555 #endif /* MEMORY_DISK_SERVER */ 556 default: 557 break; 558 } 559 break; 560 } 561 mutex_exit(&sc->sc_lock); 562 device_release(sc->sc_dev); 563 return error; 564 } 565 566 static void 567 md_set_disklabel(struct md_softc *sc) 568 { 569 struct disk_geom *dg = &sc->sc_dkdev.dk_geom; 570 struct disklabel *lp = sc->sc_dkdev.dk_label; 571 struct partition *pp; 572 573 memset(lp, 0, sizeof(*lp)); 574 575 lp->d_secsize = DEV_BSIZE; 576 lp->d_secperunit = sc->sc_size / DEV_BSIZE; 577 if (lp->d_secperunit >= (32*64)) { 578 lp->d_nsectors = 32; 579 lp->d_ntracks = 64; 580 lp->d_ncylinders = lp->d_secperunit / (32*64); 581 } else { 582 lp->d_nsectors = 1; 583 lp->d_ntracks = 1; 584 lp->d_ncylinders = lp->d_secperunit; 585 } 586 lp->d_secpercyl = lp->d_ntracks*lp->d_nsectors; 587 588 strncpy(lp->d_typename, md_cd.cd_name, sizeof(lp->d_typename)); 589 lp->d_type = DKTYPE_MD; 590 strncpy(lp->d_packname, "fictitious", sizeof(lp->d_packname)); 591 lp->d_rpm = 3600; 592 lp->d_interleave = 1; 593 lp->d_flags = 0; 594 595 pp = &lp->d_partitions[0]; 596 pp->p_offset = 0; 597 pp->p_size = lp->d_secperunit; 598 pp->p_fstype = FS_BSDFFS; 599 600 pp = &lp->d_partitions[RAW_PART]; 601 pp->p_offset = 0; 602 pp->p_size = lp->d_secperunit; 603 pp->p_fstype = FS_UNUSED; 604 605 lp->d_npartitions = RAW_PART+1; 606 lp->d_magic = DISKMAGIC; 607 lp->d_magic2 = DISKMAGIC; 608 lp->d_checksum = dkcksum(lp); 609 610 memset(dg, 0, sizeof(*dg)); 611 612 dg->dg_secsize = lp->d_secsize; 613 dg->dg_secperunit = lp->d_secperunit; 614 dg->dg_nsectors = lp->d_nsectors; 615 dg->dg_ntracks = lp->d_ntracks = 64;; 616 dg->dg_ncylinders = lp->d_ncylinders; 617 618 disk_set_info(sc->sc_dev, &sc->sc_dkdev, NULL); 619 } 620 621 /* 622 * Handle ioctl MD_SETCONF for (sc_type == MD_KMEM_ALLOCATED) 623 * Just allocate some kernel memory and return. 624 */ 625 static int 626 md_ioctl_kalloc(struct md_softc *sc, struct md_conf *umd, 627 struct lwp *l) 628 { 629 vaddr_t addr; 630 vsize_t size; 631 632 mutex_exit(&sc->sc_lock); 633 634 /* Sanity check the size. */ 635 size = umd->md_size; 636 addr = uvm_km_alloc(kernel_map, size, 0, UVM_KMF_WIRED|UVM_KMF_ZERO); 637 638 mutex_enter(&sc->sc_lock); 639 640 if (!addr) 641 return ENOMEM; 642 643 /* If another thread beat us to configure this unit: fail. */ 644 if (sc->sc_type != MD_UNCONFIGURED) { 645 uvm_km_free(kernel_map, addr, size, UVM_KMF_WIRED); 646 return EINVAL; 647 } 648 649 /* This unit is now configured. */ 650 sc->sc_addr = (void *)addr; /* kernel space */ 651 sc->sc_size = (size_t)size; 652 sc->sc_type = MD_KMEM_ALLOCATED; 653 md_set_disklabel(sc); 654 return 0; 655 } 656 657 #if MEMORY_DISK_SERVER 658 659 /* 660 * Handle ioctl MD_SETCONF for (sc_type == MD_UMEM_SERVER) 661 * Set config, then become the I/O server for this unit. 662 */ 663 static int 664 md_ioctl_server(struct md_softc *sc, struct md_conf *umd, 665 struct lwp *l) 666 { 667 vaddr_t end; 668 int error; 669 670 KASSERT(mutex_owned(&sc->sc_lock)); 671 672 /* Sanity check addr, size. */ 673 end = (vaddr_t) ((char *)umd->md_addr + umd->md_size); 674 675 if ((end >= VM_MAXUSER_ADDRESS) || 676 (end < ((vaddr_t) umd->md_addr)) ) 677 return EINVAL; 678 679 /* This unit is now configured. */ 680 sc->sc_addr = umd->md_addr; /* user space */ 681 sc->sc_size = umd->md_size; 682 sc->sc_type = MD_UMEM_SERVER; 683 md_set_disklabel(sc); 684 685 /* Become the server daemon */ 686 error = md_server_loop(sc); 687 688 /* This server is now going away! */ 689 sc->sc_type = MD_UNCONFIGURED; 690 sc->sc_addr = 0; 691 sc->sc_size = 0; 692 693 return (error); 694 } 695 696 static int 697 md_server_loop(struct md_softc *sc) 698 { 699 struct buf *bp; 700 void *addr; /* user space address */ 701 size_t off; /* offset into "device" */ 702 size_t xfer; /* amount to transfer */ 703 int error; 704 bool is_read; 705 706 KASSERT(mutex_owned(&sc->sc_lock)); 707 708 for (;;) { 709 /* Wait for some work to arrive. */ 710 while ((bp = bufq_get(sc->sc_buflist)) == NULL) { 711 error = cv_wait_sig(&sc->sc_cv, &sc->sc_lock); 712 if (error) 713 return error; 714 } 715 716 /* Do the transfer to/from user space. */ 717 mutex_exit(&sc->sc_lock); 718 error = 0; 719 is_read = ((bp->b_flags & B_READ) == B_READ); 720 bp->b_resid = bp->b_bcount; 721 off = (bp->b_blkno << DEV_BSHIFT); 722 if (off >= sc->sc_size) { 723 if (is_read) 724 goto done; /* EOF (not an error) */ 725 error = EIO; 726 goto done; 727 } 728 xfer = bp->b_resid; 729 if (xfer > (sc->sc_size - off)) 730 xfer = (sc->sc_size - off); 731 addr = (char *)sc->sc_addr + off; 732 disk_busy(&sc->sc_dkdev); 733 if (is_read) 734 error = copyin(addr, bp->b_data, xfer); 735 else 736 error = copyout(bp->b_data, addr, xfer); 737 disk_unbusy(&sc->sc_dkdev, (error ? 0 : xfer), is_read); 738 if (!error) 739 bp->b_resid -= xfer; 740 741 done: 742 if (error) { 743 bp->b_error = error; 744 } 745 biodone(bp); 746 mutex_enter(&sc->sc_lock); 747 } 748 } 749 #endif /* MEMORY_DISK_SERVER */ 750
Indexes created Tue Sep 30 20:09:53 GMT 2025