md.c revision 1.76.2.5
1 /* $NetBSD: md.c,v 1.76.2.5 2016/07/27 03:25:00 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 1.76.2.5 2016/07/27 03:25:00 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 device_t self; 247 struct md_softc *sc; 248 int res; 249 250 self = device_lookup_acquire(&md_cd, MD_UNIT(dev)); 251 if (self == NULL) 252 return 0; 253 sc = device_private(self); 254 255 mutex_enter(&sc->sc_lock); 256 if (sc->sc_type == MD_UNCONFIGURED) 257 res = 0; 258 else 259 res = sc->sc_size >> DEV_BSHIFT; 260 mutex_exit(&sc->sc_lock); 261 262 device_release(self); 263 return res; 264 } 265 266 static int 267 mdopen(dev_t dev, int flag, int fmt, struct lwp *l) 268 { 269 device_t self; 270 int unit; 271 int part = DISKPART(dev); 272 int pmask = 1 << part; 273 cfdata_t cf; 274 struct md_softc *sc; 275 struct disk *dk; 276 #ifdef MEMORY_DISK_HOOKS 277 bool configured; 278 #endif 279 280 mutex_enter(&md_device_lock); 281 unit = MD_UNIT(dev); 282 sc = NULL; 283 self = device_lookup_acquire(&md_cd, unit); 284 if (self == NULL) { 285 if (part != RAW_PART) { 286 mutex_exit(&md_device_lock); 287 return ENXIO; 288 } 289 cf = malloc(sizeof(*cf), M_DEVBUF, M_WAITOK); 290 cf->cf_name = md_cd.cd_name; 291 cf->cf_atname = md_cd.cd_name; 292 cf->cf_unit = unit; 293 cf->cf_fstate = FSTATE_STAR; 294 self = config_attach_pseudo(cf); 295 if (self != NULL) { 296 device_acquire(self); 297 sc = device_private(self); 298 } 299 if (sc == NULL) { 300 mutex_exit(&md_device_lock); 301 device_release(self); 302 return ENOMEM; 303 } 304 } 305 else 306 sc = device_private(self); 307 308 dk = &sc->sc_dkdev; 309 310 /* 311 * The raw partition is used for ioctl to configure. 312 */ 313 if (part == RAW_PART) 314 goto ok; 315 316 #ifdef MEMORY_DISK_HOOKS 317 /* Call the open hook to allow loading the device. */ 318 configured = (sc->sc_type != MD_UNCONFIGURED); 319 md_open_hook(unit, &sc->sc_md); 320 /* initialize disklabel if the device is configured in open hook */ 321 if (!configured && sc->sc_type != MD_UNCONFIGURED) 322 md_set_disklabel(sc); 323 #endif 324 325 /* 326 * This is a normal, "slave" device, so 327 * enforce initialized. 328 */ 329 if (sc->sc_type == MD_UNCONFIGURED) { 330 mutex_exit(&md_device_lock); 331 device_release(self); 332 return ENXIO; 333 } 334 335 ok: 336 /* XXX duplicates code in dk_open(). Call dk_open(), instead? */ 337 mutex_enter(&dk->dk_openlock); 338 /* Mark our unit as open. */ 339 switch (fmt) { 340 case S_IFCHR: 341 dk->dk_copenmask |= pmask; 342 break; 343 case S_IFBLK: 344 dk->dk_bopenmask |= pmask; 345 break; 346 } 347 348 dk->dk_openmask = dk->dk_copenmask | dk->dk_bopenmask; 349 350 mutex_exit(&dk->dk_openlock); 351 mutex_exit(&md_device_lock); 352 device_release(self); 353 return 0; 354 } 355 356 static int 357 mdclose(dev_t dev, int flag, int fmt, struct lwp *l) 358 { 359 device_t self; 360 int part = DISKPART(dev); 361 int pmask = 1 << part; 362 int error; 363 cfdata_t cf; 364 struct md_softc *sc; 365 struct disk *dk; 366 367 self = device_lookup_acquire(&md_cd, MD_UNIT(dev)); 368 if (self == NULL) 369 return ENXIO; 370 sc = device_private(self); 371 372 dk = &sc->sc_dkdev; 373 374 mutex_enter(&dk->dk_openlock); 375 376 switch (fmt) { 377 case S_IFCHR: 378 dk->dk_copenmask &= ~pmask; 379 break; 380 case S_IFBLK: 381 dk->dk_bopenmask &= ~pmask; 382 break; 383 } 384 dk->dk_openmask = dk->dk_copenmask | dk->dk_bopenmask; 385 if (dk->dk_openmask != 0) { 386 mutex_exit(&dk->dk_openlock); 387 device_release(self); 388 return 0; 389 } 390 391 mutex_exit(&dk->dk_openlock); 392 393 mutex_enter(&md_device_lock); 394 cf = device_cfdata(sc->sc_dev); 395 error = config_detach(sc->sc_dev, DETACH_QUIET); 396 if (! error) 397 free(cf, M_DEVBUF); 398 mutex_exit(&md_device_lock); 399 device_release(self); 400 return error; 401 } 402 403 static int 404 mdread(dev_t dev, struct uio *uio, int flags) 405 { 406 device_t self; 407 struct md_softc *sc; 408 int error; 409 410 self = device_lookup_acquire(&md_cd, MD_UNIT(dev)); 411 if (self == NULL) 412 return ENXIO; 413 414 sc = device_private(self); 415 if (sc == NULL || sc->sc_type == MD_UNCONFIGURED) { 416 device_release(self); 417 return ENXIO; 418 } 419 420 error = (physio(mdstrategy, NULL, dev, B_READ, minphys, uio)); 421 device_release(self); 422 return error; 423 } 424 425 static int 426 mdwrite(dev_t dev, struct uio *uio, int flags) 427 { 428 device_t self; 429 struct md_softc *sc; 430 int error; 431 432 self = device_lookup_acquire(&md_cd, MD_UNIT(dev)); 433 if (self == NULL) 434 return ENXIO; 435 436 sc = device_private(self); 437 if (sc == NULL || sc->sc_type == MD_UNCONFIGURED) { 438 device_release(self); 439 return ENXIO; 440 } 441 442 error = (physio(mdstrategy, NULL, dev, B_WRITE, minphys, uio)); 443 444 device_release(self); 445 return error; 446 } 447 448 /* 449 * Handle I/O requests, either directly, or 450 * by passing them to the server process. 451 */ 452 static void 453 mdstrategy(struct buf *bp) 454 { 455 device_t self; 456 struct md_softc *sc; 457 void * addr; 458 size_t off, xfer; 459 bool is_read; 460 461 self = device_lookup_acquire(&md_cd, MD_UNIT(bp->b_dev)); 462 if (self == NULL) { 463 bp->b_error = ENXIO; 464 goto done; 465 } 466 467 sc = device_private(self); 468 if (sc->sc_type == MD_UNCONFIGURED) { 469 bp->b_error = ENXIO; 470 goto done; 471 } 472 mutex_enter(&sc->sc_lock); 473 474 switch (sc->sc_type) { 475 #if MEMORY_DISK_SERVER 476 case MD_UMEM_SERVER: 477 /* Just add this job to the server's queue. */ 478 bufq_put(sc->sc_buflist, bp); 479 cv_signal(&sc->sc_cv); 480 mutex_exit(&sc->sc_lock); 481 /* see md_server_loop() */ 482 /* no biodone in this case */ 483 device_release(self); 484 return; 485 #endif /* MEMORY_DISK_SERVER */ 486 487 case MD_KMEM_FIXED: 488 case MD_KMEM_ALLOCATED: 489 /* These are in kernel space. Access directly. */ 490 is_read = ((bp->b_flags & B_READ) == B_READ); 491 bp->b_resid = bp->b_bcount; 492 off = (bp->b_blkno << DEV_BSHIFT); 493 if (off >= sc->sc_size) { 494 if (is_read) 495 break; /* EOF */ 496 goto set_eio; 497 } 498 xfer = bp->b_resid; 499 if (xfer > (sc->sc_size - off)) 500 xfer = (sc->sc_size - off); 501 addr = (char *)sc->sc_addr + off; 502 disk_busy(&sc->sc_dkdev); 503 if (is_read) 504 memcpy(bp->b_data, addr, xfer); 505 else 506 memcpy(addr, bp->b_data, xfer); 507 disk_unbusy(&sc->sc_dkdev, xfer, is_read); 508 bp->b_resid -= xfer; 509 break; 510 511 default: 512 bp->b_resid = bp->b_bcount; 513 set_eio: 514 bp->b_error = EIO; 515 break; 516 } 517 518 mutex_exit(&sc->sc_lock); 519 done: 520 biodone(bp); 521 if (self != NULL) 522 device_release(self); 523 } 524 525 static int 526 mdioctl(dev_t dev, u_long cmd, void *data, int flag, struct lwp *l) 527 { 528 device_t self; 529 struct md_softc *sc; 530 struct md_conf *umd; 531 int error; 532 533 self = device_lookup_private(&md_cd, MD_UNIT(dev)); 534 if (self == NULL) 535 return ENXIO; 536 537 sc = device_private(self); 538 mutex_enter(&sc->sc_lock); 539 if (sc->sc_type != MD_UNCONFIGURED) { 540 error = disk_ioctl(&sc->sc_dkdev, dev, cmd, data, flag, l); 541 if (error != EPASSTHROUGH) { 542 mutex_exit(&sc->sc_lock); 543 device_release(self); 544 return 0; 545 } 546 } 547 548 /* If this is not the raw partition, punt! */ 549 if (DISKPART(dev) != RAW_PART) { 550 mutex_exit(&sc->sc_lock); 551 device_release(self); 552 return ENOTTY; 553 } 554 555 umd = (struct md_conf *)data; 556 error = EINVAL; 557 switch (cmd) { 558 case MD_GETCONF: 559 *umd = sc->sc_md; 560 error = 0; 561 break; 562 563 case MD_SETCONF: 564 /* Can only set it once. */ 565 if (sc->sc_type != MD_UNCONFIGURED) 566 break; 567 switch (umd->md_type) { 568 case MD_KMEM_ALLOCATED: 569 error = md_ioctl_kalloc(sc, umd, l); 570 break; 571 #if MEMORY_DISK_SERVER 572 case MD_UMEM_SERVER: 573 error = md_ioctl_server(sc, umd, l); 574 break; 575 #endif /* MEMORY_DISK_SERVER */ 576 default: 577 break; 578 } 579 break; 580 } 581 mutex_exit(&sc->sc_lock); 582 device_release(self); 583 return error; 584 } 585 586 static void 587 md_set_disklabel(struct md_softc *sc) 588 { 589 struct disk_geom *dg = &sc->sc_dkdev.dk_geom; 590 struct disklabel *lp = sc->sc_dkdev.dk_label; 591 struct partition *pp; 592 593 memset(lp, 0, sizeof(*lp)); 594 595 lp->d_secsize = DEV_BSIZE; 596 lp->d_secperunit = sc->sc_size / DEV_BSIZE; 597 if (lp->d_secperunit >= (32*64)) { 598 lp->d_nsectors = 32; 599 lp->d_ntracks = 64; 600 lp->d_ncylinders = lp->d_secperunit / (32*64); 601 } else { 602 lp->d_nsectors = 1; 603 lp->d_ntracks = 1; 604 lp->d_ncylinders = lp->d_secperunit; 605 } 606 lp->d_secpercyl = lp->d_ntracks*lp->d_nsectors; 607 608 strncpy(lp->d_typename, md_cd.cd_name, sizeof(lp->d_typename)); 609 lp->d_type = DKTYPE_MD; 610 strncpy(lp->d_packname, "fictitious", sizeof(lp->d_packname)); 611 lp->d_rpm = 3600; 612 lp->d_interleave = 1; 613 lp->d_flags = 0; 614 615 pp = &lp->d_partitions[0]; 616 pp->p_offset = 0; 617 pp->p_size = lp->d_secperunit; 618 pp->p_fstype = FS_BSDFFS; 619 620 pp = &lp->d_partitions[RAW_PART]; 621 pp->p_offset = 0; 622 pp->p_size = lp->d_secperunit; 623 pp->p_fstype = FS_UNUSED; 624 625 lp->d_npartitions = RAW_PART+1; 626 lp->d_magic = DISKMAGIC; 627 lp->d_magic2 = DISKMAGIC; 628 lp->d_checksum = dkcksum(lp); 629 630 memset(dg, 0, sizeof(*dg)); 631 632 dg->dg_secsize = lp->d_secsize; 633 dg->dg_secperunit = lp->d_secperunit; 634 dg->dg_nsectors = lp->d_nsectors; 635 dg->dg_ntracks = lp->d_ntracks = 64;; 636 dg->dg_ncylinders = lp->d_ncylinders; 637 638 disk_set_info(sc->sc_dev, &sc->sc_dkdev, NULL); 639 } 640 641 /* 642 * Handle ioctl MD_SETCONF for (sc_type == MD_KMEM_ALLOCATED) 643 * Just allocate some kernel memory and return. 644 */ 645 static int 646 md_ioctl_kalloc(struct md_softc *sc, struct md_conf *umd, 647 struct lwp *l) 648 { 649 vaddr_t addr; 650 vsize_t size; 651 652 mutex_exit(&sc->sc_lock); 653 654 /* Sanity check the size. */ 655 size = umd->md_size; 656 addr = uvm_km_alloc(kernel_map, size, 0, UVM_KMF_WIRED|UVM_KMF_ZERO); 657 658 mutex_enter(&sc->sc_lock); 659 660 if (!addr) 661 return ENOMEM; 662 663 /* If another thread beat us to configure this unit: fail. */ 664 if (sc->sc_type != MD_UNCONFIGURED) { 665 uvm_km_free(kernel_map, addr, size, UVM_KMF_WIRED); 666 return EINVAL; 667 } 668 669 /* This unit is now configured. */ 670 sc->sc_addr = (void *)addr; /* kernel space */ 671 sc->sc_size = (size_t)size; 672 sc->sc_type = MD_KMEM_ALLOCATED; 673 md_set_disklabel(sc); 674 return 0; 675 } 676 677 #if MEMORY_DISK_SERVER 678 679 /* 680 * Handle ioctl MD_SETCONF for (sc_type == MD_UMEM_SERVER) 681 * Set config, then become the I/O server for this unit. 682 */ 683 static int 684 md_ioctl_server(struct md_softc *sc, struct md_conf *umd, 685 struct lwp *l) 686 { 687 vaddr_t end; 688 int error; 689 690 KASSERT(mutex_owned(&sc->sc_lock)); 691 692 /* Sanity check addr, size. */ 693 end = (vaddr_t) ((char *)umd->md_addr + umd->md_size); 694 695 if ((end >= VM_MAXUSER_ADDRESS) || 696 (end < ((vaddr_t) umd->md_addr)) ) 697 return EINVAL; 698 699 /* This unit is now configured. */ 700 sc->sc_addr = umd->md_addr; /* user space */ 701 sc->sc_size = umd->md_size; 702 sc->sc_type = MD_UMEM_SERVER; 703 md_set_disklabel(sc); 704 705 /* Become the server daemon */ 706 error = md_server_loop(sc); 707 708 /* This server is now going away! */ 709 sc->sc_type = MD_UNCONFIGURED; 710 sc->sc_addr = 0; 711 sc->sc_size = 0; 712 713 return (error); 714 } 715 716 static int 717 md_server_loop(struct md_softc *sc) 718 { 719 struct buf *bp; 720 void *addr; /* user space address */ 721 size_t off; /* offset into "device" */ 722 size_t xfer; /* amount to transfer */ 723 int error; 724 bool is_read; 725 726 KASSERT(mutex_owned(&sc->sc_lock)); 727 728 for (;;) { 729 /* Wait for some work to arrive. */ 730 while ((bp = bufq_get(sc->sc_buflist)) == NULL) { 731 error = cv_wait_sig(&sc->sc_cv, &sc->sc_lock); 732 if (error) 733 return error; 734 } 735 736 /* Do the transfer to/from user space. */ 737 mutex_exit(&sc->sc_lock); 738 error = 0; 739 is_read = ((bp->b_flags & B_READ) == B_READ); 740 bp->b_resid = bp->b_bcount; 741 off = (bp->b_blkno << DEV_BSHIFT); 742 if (off >= sc->sc_size) { 743 if (is_read) 744 goto done; /* EOF (not an error) */ 745 error = EIO; 746 goto done; 747 } 748 xfer = bp->b_resid; 749 if (xfer > (sc->sc_size - off)) 750 xfer = (sc->sc_size - off); 751 addr = (char *)sc->sc_addr + off; 752 disk_busy(&sc->sc_dkdev); 753 if (is_read) 754 error = copyin(addr, bp->b_data, xfer); 755 else 756 error = copyout(bp->b_data, addr, xfer); 757 disk_unbusy(&sc->sc_dkdev, (error ? 0 : xfer), is_read); 758 if (!error) 759 bp->b_resid -= xfer; 760 761 done: 762 if (error) { 763 bp->b_error = error; 764 } 765 biodone(bp); 766 mutex_enter(&sc->sc_lock); 767 } 768 } 769 #endif /* MEMORY_DISK_SERVER */ 770
Indexes created Tue Sep 30 20:09:53 GMT 2025