1/*- 2 * Copyright (c) 2011, Bryan Venteicher <bryanv@FreeBSD.org> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice unmodified, this list of conditions, and the following 10 * disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 */ 26 27/* Driver for VirtIO block devices. */ 28 29#include <sys/cdefs.h> 30__FBSDID("$FreeBSD$"); 31 32#include <sys/param.h> 33#include <sys/systm.h> 34#include <sys/kernel.h> 35#include <sys/bio.h> 36#include <sys/malloc.h> 37#include <sys/module.h> 38#include <sys/sglist.h> 39#include <sys/sysctl.h> 40#include <sys/lock.h> 41#include <sys/mutex.h> 42#include <sys/queue.h> 43 44#include <geom/geom_disk.h> 45 46#include <machine/bus.h> 47#include <machine/resource.h> 48#include <sys/bus.h> 49#include <sys/rman.h> 50 51#include <dev/virtio/virtio.h> 52#include <dev/virtio/virtqueue.h> 53#include <dev/virtio/block/virtio_blk.h> 54 55#include "virtio_if.h" 56 57struct vtblk_request { 58 struct virtio_blk_outhdr vbr_hdr; 59 struct bio *vbr_bp; 60 uint8_t vbr_ack; 61 62 TAILQ_ENTRY(vtblk_request) vbr_link; 63}; 64 65enum vtblk_cache_mode { 66 VTBLK_CACHE_WRITETHROUGH, 67 VTBLK_CACHE_WRITEBACK, 68 VTBLK_CACHE_MAX 69}; 70 71struct vtblk_softc { 72 device_t vtblk_dev; 73 struct mtx vtblk_mtx; 74 uint64_t vtblk_features; 75 uint32_t vtblk_flags; 76#define VTBLK_FLAG_INDIRECT 0x0001 77#define VTBLK_FLAG_READONLY 0x0002 78#define VTBLK_FLAG_DETACH 0x0004 79#define VTBLK_FLAG_SUSPEND 0x0008 80#define VTBLK_FLAG_DUMPING 0x0010 81#define VTBLK_FLAG_BARRIER 0x0020 82#define VTBLK_FLAG_WC_CONFIG 0x0040 83 84 struct virtqueue *vtblk_vq; 85 struct sglist *vtblk_sglist; 86 struct disk *vtblk_disk; 87 88 struct bio_queue_head vtblk_bioq; 89 TAILQ_HEAD(, vtblk_request) 90 vtblk_req_free; 91 TAILQ_HEAD(, vtblk_request) 92 vtblk_req_ready; 93 struct vtblk_request *vtblk_req_ordered; 94 95 int vtblk_max_nsegs; 96 int vtblk_request_count; 97 enum vtblk_cache_mode vtblk_write_cache; 98 99 struct vtblk_request vtblk_dump_request; 100}; 101 102static struct virtio_feature_desc vtblk_feature_desc[] = { 103 { VIRTIO_BLK_F_BARRIER, "HostBarrier" }, 104 { VIRTIO_BLK_F_SIZE_MAX, "MaxSegSize" }, 105 { VIRTIO_BLK_F_SEG_MAX, "MaxNumSegs" }, 106 { VIRTIO_BLK_F_GEOMETRY, "DiskGeometry" }, 107 { VIRTIO_BLK_F_RO, "ReadOnly" }, 108 { VIRTIO_BLK_F_BLK_SIZE, "BlockSize" }, 109 { VIRTIO_BLK_F_SCSI, "SCSICmds" }, 110 { VIRTIO_BLK_F_WCE, "WriteCache" }, 111 { VIRTIO_BLK_F_TOPOLOGY, "Topology" }, 112 { VIRTIO_BLK_F_CONFIG_WCE, "ConfigWCE" }, 113 114 { 0, NULL } 115}; 116 117static int vtblk_modevent(module_t, int, void *); 118 119static int vtblk_probe(device_t); 120static int vtblk_attach(device_t); 121static int vtblk_detach(device_t); 122static int vtblk_suspend(device_t); 123static int vtblk_resume(device_t); 124static int vtblk_shutdown(device_t); 125static int vtblk_config_change(device_t); 126 127static int vtblk_open(struct disk *); 128static int vtblk_close(struct disk *); 129static int vtblk_ioctl(struct disk *, u_long, void *, int, 130 struct thread *); 131static int vtblk_dump(void *, void *, vm_offset_t, off_t, size_t); 132static void vtblk_strategy(struct bio *); 133 134static void vtblk_negotiate_features(struct vtblk_softc *); 135static int vtblk_maximum_segments(struct vtblk_softc *, 136 struct virtio_blk_config *); 137static int vtblk_alloc_virtqueue(struct vtblk_softc *); 138static void vtblk_resize_disk(struct vtblk_softc *, uint64_t); 139static void vtblk_set_write_cache(struct vtblk_softc *, int); 140static int vtblk_write_cache_enabled(struct vtblk_softc *sc, 141 struct virtio_blk_config *); 142static int vtblk_write_cache_sysctl(SYSCTL_HANDLER_ARGS); 143static void vtblk_alloc_disk(struct vtblk_softc *, 144 struct virtio_blk_config *); 145static void vtblk_create_disk(struct vtblk_softc *); 146 147static int vtblk_quiesce(struct vtblk_softc *); 148static void vtblk_startio(struct vtblk_softc *); 149static struct vtblk_request * vtblk_bio_request(struct vtblk_softc *); 150static int vtblk_execute_request(struct vtblk_softc *, 151 struct vtblk_request *); 152 153static void vtblk_vq_intr(void *); 154 155static void vtblk_stop(struct vtblk_softc *); 156 157static void vtblk_read_config(struct vtblk_softc *, 158 struct virtio_blk_config *); 159static void vtblk_get_ident(struct vtblk_softc *); 160static void vtblk_prepare_dump(struct vtblk_softc *); 161static int vtblk_write_dump(struct vtblk_softc *, void *, off_t, size_t); 162static int vtblk_flush_dump(struct vtblk_softc *); 163static int vtblk_poll_request(struct vtblk_softc *, 164 struct vtblk_request *); 165 166static void vtblk_finish_completed(struct vtblk_softc *); 167static void vtblk_drain_vq(struct vtblk_softc *, int); 168static void vtblk_drain(struct vtblk_softc *); 169 170static int vtblk_alloc_requests(struct vtblk_softc *); 171static void vtblk_free_requests(struct vtblk_softc *); 172static struct vtblk_request * vtblk_dequeue_request(struct vtblk_softc *); 173static void vtblk_enqueue_request(struct vtblk_softc *, 174 struct vtblk_request *); 175 176static struct vtblk_request * vtblk_dequeue_ready(struct vtblk_softc *); 177static void vtblk_enqueue_ready(struct vtblk_softc *, 178 struct vtblk_request *); 179 180static int vtblk_request_error(struct vtblk_request *); 181static void vtblk_finish_bio(struct bio *, int); 182 183static void vtblk_setup_sysctl(struct vtblk_softc *); 184static int vtblk_tunable_int(struct vtblk_softc *, const char *, int); 185 186/* Tunables. */ 187static int vtblk_no_ident = 0; 188TUNABLE_INT("hw.vtblk.no_ident", &vtblk_no_ident); 189static int vtblk_writecache_mode = -1; 190TUNABLE_INT("hw.vtblk.writecache_mode", &vtblk_writecache_mode); 191 192/* Features desired/implemented by this driver. */ 193#define VTBLK_FEATURES \ 194 (VIRTIO_BLK_F_BARRIER | \ 195 VIRTIO_BLK_F_SIZE_MAX | \ 196 VIRTIO_BLK_F_SEG_MAX | \ 197 VIRTIO_BLK_F_GEOMETRY | \ 198 VIRTIO_BLK_F_RO | \ 199 VIRTIO_BLK_F_BLK_SIZE | \ 200 VIRTIO_BLK_F_WCE | \ 201 VIRTIO_BLK_F_CONFIG_WCE | \ 202 VIRTIO_RING_F_INDIRECT_DESC) 203 204#define VTBLK_MTX(_sc) &(_sc)->vtblk_mtx 205#define VTBLK_LOCK_INIT(_sc, _name) \ 206 mtx_init(VTBLK_MTX((_sc)), (_name), \ 207 "VirtIO Block Lock", MTX_DEF) 208#define VTBLK_LOCK(_sc) mtx_lock(VTBLK_MTX((_sc))) 209#define VTBLK_UNLOCK(_sc) mtx_unlock(VTBLK_MTX((_sc))) 210#define VTBLK_LOCK_DESTROY(_sc) mtx_destroy(VTBLK_MTX((_sc))) 211#define VTBLK_LOCK_ASSERT(_sc) mtx_assert(VTBLK_MTX((_sc)), MA_OWNED) 212#define VTBLK_LOCK_ASSERT_NOTOWNED(_sc) \ 213 mtx_assert(VTBLK_MTX((_sc)), MA_NOTOWNED) 214 215#define VTBLK_DISK_NAME "vtbd" 216#define VTBLK_QUIESCE_TIMEOUT (30 * hz) 217 218/* 219 * Each block request uses at least two segments - one for the header 220 * and one for the status. 221 */ 222#define VTBLK_MIN_SEGMENTS 2 223 224static device_method_t vtblk_methods[] = { 225 /* Device methods. */ 226 DEVMETHOD(device_probe, vtblk_probe), 227 DEVMETHOD(device_attach, vtblk_attach), 228 DEVMETHOD(device_detach, vtblk_detach), 229 DEVMETHOD(device_suspend, vtblk_suspend), 230 DEVMETHOD(device_resume, vtblk_resume), 231 DEVMETHOD(device_shutdown, vtblk_shutdown), 232 233 /* VirtIO methods. */ 234 DEVMETHOD(virtio_config_change, vtblk_config_change), 235 236 DEVMETHOD_END 237}; 238 239static driver_t vtblk_driver = { 240 "vtblk", 241 vtblk_methods, 242 sizeof(struct vtblk_softc) 243}; 244static devclass_t vtblk_devclass; 245 246DRIVER_MODULE(virtio_blk, virtio_pci, vtblk_driver, vtblk_devclass, 247 vtblk_modevent, 0); 248MODULE_VERSION(virtio_blk, 1); 249MODULE_DEPEND(virtio_blk, virtio, 1, 1, 1); 250 251static int 252vtblk_modevent(module_t mod, int type, void *unused) 253{ 254 int error; 255 256 error = 0; 257 258 switch (type) { 259 case MOD_LOAD: 260 case MOD_QUIESCE: 261 case MOD_UNLOAD: 262 case MOD_SHUTDOWN: 263 break; 264 default: 265 error = EOPNOTSUPP; 266 break; 267 } 268 269 return (error); 270} 271 272static int 273vtblk_probe(device_t dev) 274{ 275 276 if (virtio_get_device_type(dev) != VIRTIO_ID_BLOCK) 277 return (ENXIO); 278 279 device_set_desc(dev, "VirtIO Block Adapter"); 280 281 return (BUS_PROBE_DEFAULT); 282} 283 284static int 285vtblk_attach(device_t dev) 286{ 287 struct vtblk_softc *sc; 288 struct virtio_blk_config blkcfg; 289 int error; 290 291 sc = device_get_softc(dev); 292 sc->vtblk_dev = dev; 293 294 VTBLK_LOCK_INIT(sc, device_get_nameunit(dev)); 295 296 bioq_init(&sc->vtblk_bioq); 297 TAILQ_INIT(&sc->vtblk_req_free); 298 TAILQ_INIT(&sc->vtblk_req_ready); 299 300 virtio_set_feature_desc(dev, vtblk_feature_desc); 301 vtblk_negotiate_features(sc); 302 303 if (virtio_with_feature(dev, VIRTIO_RING_F_INDIRECT_DESC)) 304 sc->vtblk_flags |= VTBLK_FLAG_INDIRECT; 305 if (virtio_with_feature(dev, VIRTIO_BLK_F_RO)) 306 sc->vtblk_flags |= VTBLK_FLAG_READONLY; 307 if (virtio_with_feature(dev, VIRTIO_BLK_F_BARRIER)) 308 sc->vtblk_flags |= VTBLK_FLAG_BARRIER; 309 if (virtio_with_feature(dev, VIRTIO_BLK_F_CONFIG_WCE)) 310 sc->vtblk_flags |= VTBLK_FLAG_WC_CONFIG; 311 312 vtblk_setup_sysctl(sc); 313 314 /* Get local copy of config. */ 315 vtblk_read_config(sc, &blkcfg); 316 317 /* 318 * With the current sglist(9) implementation, it is not easy 319 * for us to support a maximum segment size as adjacent 320 * segments are coalesced. For now, just make sure it's larger 321 * than the maximum supported transfer size. 322 */ 323 if (virtio_with_feature(dev, VIRTIO_BLK_F_SIZE_MAX)) { 324 if (blkcfg.size_max < MAXPHYS) { 325 error = ENOTSUP; 326 device_printf(dev, "host requires unsupported " 327 "maximum segment size feature\n"); 328 goto fail; 329 } 330 } 331 332 sc->vtblk_max_nsegs = vtblk_maximum_segments(sc, &blkcfg); 333 if (sc->vtblk_max_nsegs <= VTBLK_MIN_SEGMENTS) { 334 error = EINVAL; 335 device_printf(dev, "fewer than minimum number of segments " 336 "allowed: %d\n", sc->vtblk_max_nsegs); 337 goto fail; 338 } 339 340 sc->vtblk_sglist = sglist_alloc(sc->vtblk_max_nsegs, M_NOWAIT); 341 if (sc->vtblk_sglist == NULL) { 342 error = ENOMEM; 343 device_printf(dev, "cannot allocate sglist\n"); 344 goto fail; 345 } 346 347 error = vtblk_alloc_virtqueue(sc); 348 if (error) { 349 device_printf(dev, "cannot allocate virtqueue\n"); 350 goto fail; 351 } 352 353 error = vtblk_alloc_requests(sc); 354 if (error) { 355 device_printf(dev, "cannot preallocate requests\n"); 356 goto fail; 357 } 358 359 vtblk_alloc_disk(sc, &blkcfg); 360 361 error = virtio_setup_intr(dev, INTR_TYPE_BIO | INTR_ENTROPY); 362 if (error) { 363 device_printf(dev, "cannot setup virtqueue interrupt\n"); 364 goto fail; 365 } 366 367 vtblk_create_disk(sc); 368 369 virtqueue_enable_intr(sc->vtblk_vq); 370 371fail: 372 if (error) 373 vtblk_detach(dev); 374 375 return (error); 376} 377 378static int 379vtblk_detach(device_t dev) 380{ 381 struct vtblk_softc *sc; 382 383 sc = device_get_softc(dev); 384 385 VTBLK_LOCK(sc); 386 sc->vtblk_flags |= VTBLK_FLAG_DETACH; 387 if (device_is_attached(dev)) 388 vtblk_stop(sc); 389 VTBLK_UNLOCK(sc); 390 391 vtblk_drain(sc); 392 393 if (sc->vtblk_disk != NULL) { 394 disk_destroy(sc->vtblk_disk); 395 sc->vtblk_disk = NULL; 396 } 397 398 if (sc->vtblk_sglist != NULL) { 399 sglist_free(sc->vtblk_sglist); 400 sc->vtblk_sglist = NULL; 401 } 402 403 VTBLK_LOCK_DESTROY(sc); 404 405 return (0); 406} 407 408static int 409vtblk_suspend(device_t dev) 410{ 411 struct vtblk_softc *sc; 412 int error; 413 414 sc = device_get_softc(dev); 415 416 VTBLK_LOCK(sc); 417 sc->vtblk_flags |= VTBLK_FLAG_SUSPEND; 418 /* XXX BMV: virtio_stop(), etc needed here? */ 419 error = vtblk_quiesce(sc); 420 if (error) 421 sc->vtblk_flags &= ~VTBLK_FLAG_SUSPEND; 422 VTBLK_UNLOCK(sc); 423 424 return (error); 425} 426 427static int 428vtblk_resume(device_t dev) 429{ 430 struct vtblk_softc *sc; 431 432 sc = device_get_softc(dev); 433 434 VTBLK_LOCK(sc); 435 /* XXX BMV: virtio_reinit(), etc needed here? */ 436 sc->vtblk_flags &= ~VTBLK_FLAG_SUSPEND; 437 vtblk_startio(sc); 438 VTBLK_UNLOCK(sc); 439 440 return (0); 441} 442 443static int 444vtblk_shutdown(device_t dev) 445{ 446 447 return (0); 448} 449 450static int 451vtblk_config_change(device_t dev) 452{ 453 struct vtblk_softc *sc; 454 struct virtio_blk_config blkcfg; 455 uint64_t capacity; 456 457 sc = device_get_softc(dev); 458 459 vtblk_read_config(sc, &blkcfg); 460 461 /* Capacity is always in 512-byte units. */ 462 capacity = blkcfg.capacity * 512; 463 464 if (sc->vtblk_disk->d_mediasize != capacity) 465 vtblk_resize_disk(sc, capacity); 466 467 return (0); 468} 469 470static int 471vtblk_open(struct disk *dp) 472{ 473 struct vtblk_softc *sc; 474 475 if ((sc = dp->d_drv1) == NULL) 476 return (ENXIO); 477 478 return (sc->vtblk_flags & VTBLK_FLAG_DETACH ? ENXIO : 0); 479} 480 481static int 482vtblk_close(struct disk *dp) 483{ 484 struct vtblk_softc *sc; 485 486 if ((sc = dp->d_drv1) == NULL) 487 return (ENXIO); 488 489 return (0); 490} 491 492static int 493vtblk_ioctl(struct disk *dp, u_long cmd, void *addr, int flag, 494 struct thread *td) 495{ 496 struct vtblk_softc *sc; 497 498 if ((sc = dp->d_drv1) == NULL) 499 return (ENXIO); 500 501 return (ENOTTY); 502} 503 504static int 505vtblk_dump(void *arg, void *virtual, vm_offset_t physical, off_t offset, 506 size_t length) 507{ 508 struct disk *dp; 509 struct vtblk_softc *sc; 510 int error; 511 512 dp = arg; 513 514 if ((sc = dp->d_drv1) == NULL) 515 return (ENXIO); 516 517 VTBLK_LOCK(sc); 518 519 if ((sc->vtblk_flags & VTBLK_FLAG_DUMPING) == 0) { 520 vtblk_prepare_dump(sc); 521 sc->vtblk_flags |= VTBLK_FLAG_DUMPING; 522 } 523 524 if (length > 0) 525 error = vtblk_write_dump(sc, virtual, offset, length); 526 else if (virtual == NULL && offset == 0) 527 error = vtblk_flush_dump(sc); 528 else { 529 error = EINVAL; 530 sc->vtblk_flags &= ~VTBLK_FLAG_DUMPING; 531 } 532 533 VTBLK_UNLOCK(sc); 534 535 return (error); 536} 537 538static void 539vtblk_strategy(struct bio *bp) 540{ 541 struct vtblk_softc *sc; 542 543 if ((sc = bp->bio_disk->d_drv1) == NULL) { 544 vtblk_finish_bio(bp, EINVAL); 545 return; 546 } 547 548 /* 549 * Fail any write if RO. Unfortunately, there does not seem to 550 * be a better way to report our readonly'ness to GEOM above. 551 */ 552 if (sc->vtblk_flags & VTBLK_FLAG_READONLY && 553 (bp->bio_cmd == BIO_WRITE || bp->bio_cmd == BIO_FLUSH)) { 554 vtblk_finish_bio(bp, EROFS); 555 return; 556 } 557 558#ifdef INVARIANTS 559 /* 560 * Prevent read/write buffers spanning too many segments from 561 * getting into the queue. This should only trip if d_maxsize 562 * was incorrectly set. 563 */ 564 if (bp->bio_cmd == BIO_READ || bp->bio_cmd == BIO_WRITE) { 565 int nsegs, max_nsegs; 566 567 nsegs = sglist_count(bp->bio_data, bp->bio_bcount); 568 max_nsegs = sc->vtblk_max_nsegs - VTBLK_MIN_SEGMENTS; 569 570 KASSERT(nsegs <= max_nsegs, 571 ("%s: bio %p spanned too many segments: %d, max: %d", 572 __func__, bp, nsegs, max_nsegs)); 573 } 574#endif 575 576 VTBLK_LOCK(sc); 577 if (sc->vtblk_flags & VTBLK_FLAG_DETACH) 578 vtblk_finish_bio(bp, ENXIO); 579 else { 580 bioq_insert_tail(&sc->vtblk_bioq, bp); 581 582 if ((sc->vtblk_flags & VTBLK_FLAG_SUSPEND) == 0) 583 vtblk_startio(sc); 584 } 585 VTBLK_UNLOCK(sc); 586} 587 588static void 589vtblk_negotiate_features(struct vtblk_softc *sc) 590{ 591 device_t dev; 592 uint64_t features; 593 594 dev = sc->vtblk_dev; 595 features = VTBLK_FEATURES; 596 597 sc->vtblk_features = virtio_negotiate_features(dev, features); 598} 599 600static int 601vtblk_maximum_segments(struct vtblk_softc *sc, 602 struct virtio_blk_config *blkcfg) 603{ 604 device_t dev; 605 int nsegs; 606 607 dev = sc->vtblk_dev; 608 nsegs = VTBLK_MIN_SEGMENTS; 609 610 if (virtio_with_feature(dev, VIRTIO_BLK_F_SEG_MAX)) { 611 nsegs += MIN(blkcfg->seg_max, MAXPHYS / PAGE_SIZE + 1); 612 if (sc->vtblk_flags & VTBLK_FLAG_INDIRECT) 613 nsegs = MIN(nsegs, VIRTIO_MAX_INDIRECT); 614 } else 615 nsegs += 1; 616 617 return (nsegs); 618} 619 620static int 621vtblk_alloc_virtqueue(struct vtblk_softc *sc) 622{ 623 device_t dev; 624 struct vq_alloc_info vq_info; 625 626 dev = sc->vtblk_dev; 627 628 VQ_ALLOC_INFO_INIT(&vq_info, sc->vtblk_max_nsegs, 629 vtblk_vq_intr, sc, &sc->vtblk_vq, 630 "%s request", device_get_nameunit(dev)); 631 632 return (virtio_alloc_virtqueues(dev, 0, 1, &vq_info)); 633} 634 635static void 636vtblk_resize_disk(struct vtblk_softc *sc, uint64_t new_capacity) 637{ 638 device_t dev; 639 struct disk *dp; 640 int error; 641 642 dev = sc->vtblk_dev; 643 dp = sc->vtblk_disk; 644 645 dp->d_mediasize = new_capacity; 646 if (bootverbose) { 647 device_printf(dev, "resized to %juMB (%ju %u byte sectors)\n", 648 (uintmax_t) dp->d_mediasize >> 20, 649 (uintmax_t) dp->d_mediasize / dp->d_sectorsize, 650 dp->d_sectorsize); 651 } 652 653 error = disk_resize(dp, M_NOWAIT); 654 if (error) { 655 device_printf(dev, 656 "disk_resize(9) failed, error: %d\n", error); 657 } 658} 659 660static void 661vtblk_set_write_cache(struct vtblk_softc *sc, int wc) 662{ 663 664 /* Set either writeback (1) or writethrough (0) mode. */ 665 virtio_write_dev_config_1(sc->vtblk_dev, 666 offsetof(struct virtio_blk_config, writeback), wc); 667} 668 669static int 670vtblk_write_cache_enabled(struct vtblk_softc *sc, 671 struct virtio_blk_config *blkcfg) 672{ 673 int wc; 674 675 if (sc->vtblk_flags & VTBLK_FLAG_WC_CONFIG) { 676 wc = vtblk_tunable_int(sc, "writecache_mode", 677 vtblk_writecache_mode); 678 if (wc >= 0 && wc < VTBLK_CACHE_MAX) 679 vtblk_set_write_cache(sc, wc); 680 else 681 wc = blkcfg->writeback; 682 } else 683 wc = virtio_with_feature(sc->vtblk_dev, VIRTIO_BLK_F_WCE); 684 685 return (wc); 686} 687 688static int 689vtblk_write_cache_sysctl(SYSCTL_HANDLER_ARGS) 690{ 691 struct vtblk_softc *sc; 692 int wc, error; 693 694 sc = oidp->oid_arg1; 695 wc = sc->vtblk_write_cache; 696 697 error = sysctl_handle_int(oidp, &wc, 0, req); 698 if (error || req->newptr == NULL) 699 return (error); 700 if ((sc->vtblk_flags & VTBLK_FLAG_WC_CONFIG) == 0) 701 return (EPERM); 702 if (wc < 0 || wc >= VTBLK_CACHE_MAX) 703 return (EINVAL); 704 705 VTBLK_LOCK(sc); 706 sc->vtblk_write_cache = wc; 707 vtblk_set_write_cache(sc, sc->vtblk_write_cache); 708 VTBLK_UNLOCK(sc); 709 710 return (0); 711} 712 713static void 714vtblk_alloc_disk(struct vtblk_softc *sc, struct virtio_blk_config *blkcfg) 715{ 716 device_t dev; 717 struct disk *dp; 718 719 dev = sc->vtblk_dev; 720 721 sc->vtblk_disk = dp = disk_alloc(); 722 dp->d_open = vtblk_open; 723 dp->d_close = vtblk_close; 724 dp->d_ioctl = vtblk_ioctl; 725 dp->d_strategy = vtblk_strategy; 726 dp->d_name = VTBLK_DISK_NAME; 727 dp->d_unit = device_get_unit(dev); 728 dp->d_drv1 = sc; 729 dp->d_flags = DISKFLAG_CANFLUSHCACHE | DISKFLAG_UNMAPPED_BIO; 730 dp->d_hba_vendor = virtio_get_vendor(dev); 731 dp->d_hba_device = virtio_get_device(dev); 732 dp->d_hba_subvendor = virtio_get_subvendor(dev); 733 dp->d_hba_subdevice = virtio_get_subdevice(dev); 734 735 if ((sc->vtblk_flags & VTBLK_FLAG_READONLY) == 0) 736 dp->d_dump = vtblk_dump; 737 738 /* Capacity is always in 512-byte units. */ 739 dp->d_mediasize = blkcfg->capacity * 512; 740 741 if (virtio_with_feature(dev, VIRTIO_BLK_F_BLK_SIZE)) 742 dp->d_sectorsize = blkcfg->blk_size; 743 else 744 dp->d_sectorsize = 512; 745 746 /* 747 * The VirtIO maximum I/O size is given in terms of segments. 748 * However, FreeBSD limits I/O size by logical buffer size, not 749 * by physically contiguous pages. Therefore, we have to assume 750 * no pages are contiguous. This may impose an artificially low 751 * maximum I/O size. But in practice, since QEMU advertises 128 752 * segments, this gives us a maximum IO size of 125 * PAGE_SIZE, 753 * which is typically greater than MAXPHYS. Eventually we should 754 * just advertise MAXPHYS and split buffers that are too big. 755 * 756 * Note we must subtract one additional segment in case of non 757 * page aligned buffers. 758 */ 759 dp->d_maxsize = (sc->vtblk_max_nsegs - VTBLK_MIN_SEGMENTS - 1) * 760 PAGE_SIZE; 761 if (dp->d_maxsize < PAGE_SIZE) 762 dp->d_maxsize = PAGE_SIZE; /* XXX */ 763 764 if (virtio_with_feature(dev, VIRTIO_BLK_F_GEOMETRY)) { 765 dp->d_fwsectors = blkcfg->geometry.sectors; 766 dp->d_fwheads = blkcfg->geometry.heads; 767 } 768 769 if (virtio_with_feature(dev, VIRTIO_BLK_F_TOPOLOGY)) { 770 dp->d_stripesize = dp->d_sectorsize * 771 (1 << blkcfg->topology.physical_block_exp); 772 dp->d_stripeoffset = (dp->d_stripesize - 773 blkcfg->topology.alignment_offset * dp->d_sectorsize) % 774 dp->d_stripesize; 775 } 776 777 if (vtblk_write_cache_enabled(sc, blkcfg) != 0) 778 sc->vtblk_write_cache = VTBLK_CACHE_WRITEBACK; 779 else 780 sc->vtblk_write_cache = VTBLK_CACHE_WRITETHROUGH; 781} 782 783static void 784vtblk_create_disk(struct vtblk_softc *sc) 785{ 786 struct disk *dp; 787 788 dp = sc->vtblk_disk; 789 790 /* 791 * Retrieving the identification string must be done after 792 * the virtqueue interrupt is setup otherwise it will hang. 793 */ 794 vtblk_get_ident(sc); 795 796 device_printf(sc->vtblk_dev, "%juMB (%ju %u byte sectors)\n", 797 (uintmax_t) dp->d_mediasize >> 20, 798 (uintmax_t) dp->d_mediasize / dp->d_sectorsize, 799 dp->d_sectorsize); 800 801 disk_create(dp, DISK_VERSION); 802} 803 804static int 805vtblk_quiesce(struct vtblk_softc *sc) 806{ 807 int error; 808 809 error = 0; 810 811 VTBLK_LOCK_ASSERT(sc); 812 813 while (!virtqueue_empty(sc->vtblk_vq)) { 814 if (mtx_sleep(&sc->vtblk_vq, VTBLK_MTX(sc), PRIBIO, "vtblkq", 815 VTBLK_QUIESCE_TIMEOUT) == EWOULDBLOCK) { 816 error = EBUSY; 817 break; 818 } 819 } 820 821 return (error); 822} 823 824static void 825vtblk_startio(struct vtblk_softc *sc) 826{ 827 struct virtqueue *vq; 828 struct vtblk_request *req; 829 int enq; 830 831 vq = sc->vtblk_vq; 832 enq = 0; 833 834 VTBLK_LOCK_ASSERT(sc); 835 836 while (!virtqueue_full(vq)) { 837 if ((req = vtblk_dequeue_ready(sc)) == NULL) 838 req = vtblk_bio_request(sc); 839 if (req == NULL) 840 break; 841 842 if (vtblk_execute_request(sc, req) != 0) { 843 vtblk_enqueue_ready(sc, req); 844 break; 845 } 846 847 enq++; 848 } 849 850 if (enq > 0) 851 virtqueue_notify(vq); 852} 853 854static struct vtblk_request * 855vtblk_bio_request(struct vtblk_softc *sc) 856{ 857 struct bio_queue_head *bioq; 858 struct vtblk_request *req; 859 struct bio *bp; 860 861 bioq = &sc->vtblk_bioq; 862 863 if (bioq_first(bioq) == NULL) 864 return (NULL); 865 866 req = vtblk_dequeue_request(sc); 867 if (req == NULL) 868 return (NULL); 869 870 bp = bioq_takefirst(bioq); 871 req->vbr_bp = bp; 872 req->vbr_ack = -1; 873 req->vbr_hdr.ioprio = 1; 874 875 switch (bp->bio_cmd) { 876 case BIO_FLUSH: 877 req->vbr_hdr.type = VIRTIO_BLK_T_FLUSH; 878 break; 879 case BIO_READ: 880 req->vbr_hdr.type = VIRTIO_BLK_T_IN; 881 req->vbr_hdr.sector = bp->bio_offset / 512; 882 break; 883 case BIO_WRITE: 884 req->vbr_hdr.type = VIRTIO_BLK_T_OUT; 885 req->vbr_hdr.sector = bp->bio_offset / 512; 886 break; 887 default: 888 panic("%s: bio with unhandled cmd: %d", __func__, bp->bio_cmd); 889 } 890 891 return (req); 892} 893 894static int 895vtblk_execute_request(struct vtblk_softc *sc, struct vtblk_request *req) 896{ 897 struct virtqueue *vq; 898 struct sglist *sg; 899 struct bio *bp; 900 int ordered, readable, writable, error; 901 902 vq = sc->vtblk_vq; 903 sg = sc->vtblk_sglist; 904 bp = req->vbr_bp; 905 ordered = 0; 906 writable = 0; 907 908 VTBLK_LOCK_ASSERT(sc); 909 910 /* 911 * Wait until the ordered request completes before 912 * executing subsequent requests. 913 */ 914 if (sc->vtblk_req_ordered != NULL) 915 return (EBUSY); 916 917 if (bp->bio_flags & BIO_ORDERED) { 918 if ((sc->vtblk_flags & VTBLK_FLAG_BARRIER) == 0) { 919 /* 920 * This request will be executed once all 921 * the in-flight requests are completed. 922 */ 923 if (!virtqueue_empty(vq)) 924 return (EBUSY); 925 ordered = 1; 926 } else 927 req->vbr_hdr.type |= VIRTIO_BLK_T_BARRIER; 928 } 929 930 sglist_reset(sg); 931 sglist_append(sg, &req->vbr_hdr, sizeof(struct virtio_blk_outhdr)); 932 933 if (bp->bio_cmd == BIO_READ || bp->bio_cmd == BIO_WRITE) { 934 error = sglist_append_bio(sg, bp); 935 if (error || sg->sg_nseg == sg->sg_maxseg) { 936 panic("%s: data buffer too big bio:%p error:%d", 937 __func__, bp, error); 938 } 939 940 /* BIO_READ means the host writes into our buffer. */ 941 if (bp->bio_cmd == BIO_READ) 942 writable = sg->sg_nseg - 1; 943 } 944 945 writable++; 946 sglist_append(sg, &req->vbr_ack, sizeof(uint8_t)); 947 readable = sg->sg_nseg - writable; 948 949 error = virtqueue_enqueue(vq, req, sg, readable, writable); 950 if (error == 0 && ordered) 951 sc->vtblk_req_ordered = req; 952 953 return (error); 954} 955 956static void 957vtblk_vq_intr(void *xsc) 958{ 959 struct vtblk_softc *sc; 960 struct virtqueue *vq; 961 962 sc = xsc; 963 vq = sc->vtblk_vq; 964 965again: 966 VTBLK_LOCK(sc); 967 if (sc->vtblk_flags & VTBLK_FLAG_DETACH) { 968 VTBLK_UNLOCK(sc); 969 return; 970 } 971 972 vtblk_finish_completed(sc); 973 974 if ((sc->vtblk_flags & VTBLK_FLAG_SUSPEND) == 0) 975 vtblk_startio(sc); 976 else 977 wakeup(&sc->vtblk_vq); 978 979 if (virtqueue_enable_intr(vq) != 0) { 980 virtqueue_disable_intr(vq); 981 VTBLK_UNLOCK(sc); 982 goto again; 983 } 984 985 VTBLK_UNLOCK(sc); 986} 987 988static void 989vtblk_stop(struct vtblk_softc *sc) 990{ 991 992 virtqueue_disable_intr(sc->vtblk_vq); 993 virtio_stop(sc->vtblk_dev); 994} 995 996#define VTBLK_GET_CONFIG(_dev, _feature, _field, _cfg) \ 997 if (virtio_with_feature(_dev, _feature)) { \ 998 virtio_read_device_config(_dev, \ 999 offsetof(struct virtio_blk_config, _field), \ 1000 &(_cfg)->_field, sizeof((_cfg)->_field)); \ 1001 } 1002 1003static void 1004vtblk_read_config(struct vtblk_softc *sc, struct virtio_blk_config *blkcfg) 1005{ 1006 device_t dev; 1007 1008 dev = sc->vtblk_dev; 1009 1010 bzero(blkcfg, sizeof(struct virtio_blk_config)); 1011 1012 /* The capacity is always available. */ 1013 virtio_read_device_config(dev, offsetof(struct virtio_blk_config, 1014 capacity), &blkcfg->capacity, sizeof(blkcfg->capacity)); 1015 1016 /* Read the configuration if the feature was negotiated. */ 1017 VTBLK_GET_CONFIG(dev, VIRTIO_BLK_F_SIZE_MAX, size_max, blkcfg); 1018 VTBLK_GET_CONFIG(dev, VIRTIO_BLK_F_SEG_MAX, seg_max, blkcfg); 1019 VTBLK_GET_CONFIG(dev, VIRTIO_BLK_F_GEOMETRY, geometry, blkcfg); 1020 VTBLK_GET_CONFIG(dev, VIRTIO_BLK_F_BLK_SIZE, blk_size, blkcfg); 1021 VTBLK_GET_CONFIG(dev, VIRTIO_BLK_F_TOPOLOGY, topology, blkcfg); 1022 VTBLK_GET_CONFIG(dev, VIRTIO_BLK_F_CONFIG_WCE, writeback, blkcfg); 1023} 1024 1025#undef VTBLK_GET_CONFIG 1026 1027static void 1028vtblk_get_ident(struct vtblk_softc *sc) 1029{ 1030 struct bio buf; 1031 struct disk *dp; 1032 struct vtblk_request *req; 1033 int len, error; 1034 1035 dp = sc->vtblk_disk; 1036 len = MIN(VIRTIO_BLK_ID_BYTES, DISK_IDENT_SIZE); 1037 1038 if (vtblk_tunable_int(sc, "no_ident", vtblk_no_ident) != 0) 1039 return; 1040 1041 req = vtblk_dequeue_request(sc); 1042 if (req == NULL) 1043 return; 1044 1045 req->vbr_ack = -1; 1046 req->vbr_hdr.type = VIRTIO_BLK_T_GET_ID; 1047 req->vbr_hdr.ioprio = 1; 1048 req->vbr_hdr.sector = 0; 1049 1050 req->vbr_bp = &buf; 1051 bzero(&buf, sizeof(struct bio)); 1052 1053 buf.bio_cmd = BIO_READ; 1054 buf.bio_data = dp->d_ident; 1055 buf.bio_bcount = len; 1056 1057 VTBLK_LOCK(sc); 1058 error = vtblk_poll_request(sc, req); 1059 VTBLK_UNLOCK(sc); 1060 1061 vtblk_enqueue_request(sc, req); 1062 1063 if (error) { 1064 device_printf(sc->vtblk_dev, 1065 "error getting device identifier: %d\n", error); 1066 } 1067} 1068 1069static void 1070vtblk_prepare_dump(struct vtblk_softc *sc) 1071{ 1072 device_t dev; 1073 struct virtqueue *vq; 1074 1075 dev = sc->vtblk_dev; 1076 vq = sc->vtblk_vq; 1077 1078 vtblk_stop(sc); 1079 1080 /* 1081 * Drain all requests caught in-flight in the virtqueue, 1082 * skipping biodone(). When dumping, only one request is 1083 * outstanding at a time, and we just poll the virtqueue 1084 * for the response. 1085 */ 1086 vtblk_drain_vq(sc, 1); 1087 1088 if (virtio_reinit(dev, sc->vtblk_features) != 0) { 1089 panic("%s: cannot reinit VirtIO block device during dump", 1090 device_get_nameunit(dev)); 1091 } 1092 1093 virtqueue_disable_intr(vq); 1094 virtio_reinit_complete(dev); 1095} 1096 1097static int 1098vtblk_write_dump(struct vtblk_softc *sc, void *virtual, off_t offset, 1099 size_t length) 1100{ 1101 struct bio buf; 1102 struct vtblk_request *req; 1103 1104 req = &sc->vtblk_dump_request; 1105 req->vbr_ack = -1; 1106 req->vbr_hdr.type = VIRTIO_BLK_T_OUT; 1107 req->vbr_hdr.ioprio = 1; 1108 req->vbr_hdr.sector = offset / 512; 1109 1110 req->vbr_bp = &buf; 1111 bzero(&buf, sizeof(struct bio)); 1112 1113 buf.bio_cmd = BIO_WRITE; 1114 buf.bio_data = virtual; 1115 buf.bio_bcount = length; 1116 1117 return (vtblk_poll_request(sc, req)); 1118} 1119 1120static int 1121vtblk_flush_dump(struct vtblk_softc *sc) 1122{ 1123 struct bio buf; 1124 struct vtblk_request *req; 1125 1126 req = &sc->vtblk_dump_request; 1127 req->vbr_ack = -1; 1128 req->vbr_hdr.type = VIRTIO_BLK_T_FLUSH; 1129 req->vbr_hdr.ioprio = 1; 1130 req->vbr_hdr.sector = 0; 1131 1132 req->vbr_bp = &buf; 1133 bzero(&buf, sizeof(struct bio)); 1134 1135 buf.bio_cmd = BIO_FLUSH; 1136 1137 return (vtblk_poll_request(sc, req)); 1138} 1139 1140static int 1141vtblk_poll_request(struct vtblk_softc *sc, struct vtblk_request *req) 1142{ 1143 struct virtqueue *vq; 1144 int error; 1145 1146 vq = sc->vtblk_vq; 1147 1148 if (!virtqueue_empty(vq)) 1149 return (EBUSY); 1150 1151 error = vtblk_execute_request(sc, req); 1152 if (error) 1153 return (error); 1154 1155 virtqueue_notify(vq); 1156 virtqueue_poll(vq, NULL); 1157 1158 error = vtblk_request_error(req); 1159 if (error && bootverbose) { 1160 device_printf(sc->vtblk_dev, 1161 "%s: IO error: %d\n", __func__, error); 1162 } 1163 1164 return (error); 1165} 1166 1167static void 1168vtblk_finish_completed(struct vtblk_softc *sc) 1169{ 1170 struct vtblk_request *req; 1171 struct bio *bp; 1172 int error; 1173 1174 while ((req = virtqueue_dequeue(sc->vtblk_vq, NULL)) != NULL) { 1175 bp = req->vbr_bp; 1176 1177 if (sc->vtblk_req_ordered != NULL) { 1178 /* This should be the only outstanding request. */ 1179 MPASS(sc->vtblk_req_ordered == req); 1180 sc->vtblk_req_ordered = NULL; 1181 } 1182 1183 error = vtblk_request_error(req); 1184 if (error) 1185 disk_err(bp, "hard error", -1, 1); 1186 1187 vtblk_finish_bio(bp, error); 1188 vtblk_enqueue_request(sc, req); 1189 } 1190} 1191 1192static void 1193vtblk_drain_vq(struct vtblk_softc *sc, int skip_done) 1194{ 1195 struct virtqueue *vq; 1196 struct vtblk_request *req; 1197 int last; 1198 1199 vq = sc->vtblk_vq; 1200 last = 0; 1201 1202 while ((req = virtqueue_drain(vq, &last)) != NULL) { 1203 if (!skip_done) 1204 vtblk_finish_bio(req->vbr_bp, ENXIO); 1205 1206 vtblk_enqueue_request(sc, req); 1207 } 1208 1209 sc->vtblk_req_ordered = NULL; 1210 KASSERT(virtqueue_empty(vq), ("virtqueue not empty")); 1211} 1212 1213static void 1214vtblk_drain(struct vtblk_softc *sc) 1215{ 1216 struct bio_queue_head *bioq; 1217 struct vtblk_request *req; 1218 struct bio *bp; 1219 1220 bioq = &sc->vtblk_bioq; 1221 1222 if (sc->vtblk_vq != NULL) { 1223 vtblk_finish_completed(sc); 1224 vtblk_drain_vq(sc, 0); 1225 } 1226 1227 while ((req = vtblk_dequeue_ready(sc)) != NULL) { 1228 vtblk_finish_bio(req->vbr_bp, ENXIO); 1229 vtblk_enqueue_request(sc, req); 1230 } 1231 1232 while (bioq_first(bioq) != NULL) { 1233 bp = bioq_takefirst(bioq); 1234 vtblk_finish_bio(bp, ENXIO); 1235 } 1236 1237 vtblk_free_requests(sc); 1238} 1239 1240#ifdef INVARIANTS 1241static void 1242vtblk_request_invariants(struct vtblk_request *req) 1243{ 1244 int hdr_nsegs, ack_nsegs; 1245 1246 hdr_nsegs = sglist_count(&req->vbr_hdr, sizeof(req->vbr_hdr)); 1247 ack_nsegs = sglist_count(&req->vbr_ack, sizeof(req->vbr_ack)); 1248 1249 KASSERT(hdr_nsegs == 1, ("request header crossed page boundary")); 1250 KASSERT(ack_nsegs == 1, ("request ack crossed page boundary")); 1251} 1252#endif 1253 1254static int 1255vtblk_alloc_requests(struct vtblk_softc *sc) 1256{ 1257 struct vtblk_request *req; 1258 int i, nreqs; 1259 1260 nreqs = virtqueue_size(sc->vtblk_vq); 1261 1262 /* 1263 * Preallocate sufficient requests to keep the virtqueue full. Each 1264 * request consumes VTBLK_MIN_SEGMENTS or more descriptors so reduce 1265 * the number allocated when indirect descriptors are not available. 1266 */ 1267 if ((sc->vtblk_flags & VTBLK_FLAG_INDIRECT) == 0) 1268 nreqs /= VTBLK_MIN_SEGMENTS; 1269 1270 for (i = 0; i < nreqs; i++) { 1271 req = malloc(sizeof(struct vtblk_request), M_DEVBUF, M_NOWAIT); 1272 if (req == NULL) 1273 return (ENOMEM); 1274 1275#ifdef INVARIANTS 1276 vtblk_request_invariants(req); 1277#endif 1278 1279 sc->vtblk_request_count++; 1280 vtblk_enqueue_request(sc, req); 1281 } 1282 1283 return (0); 1284} 1285 1286static void 1287vtblk_free_requests(struct vtblk_softc *sc) 1288{ 1289 struct vtblk_request *req; 1290 1291 KASSERT(TAILQ_EMPTY(&sc->vtblk_req_ready), 1292 ("%s: ready requests left on queue", __func__)); 1293 1294 while ((req = vtblk_dequeue_request(sc)) != NULL) { 1295 sc->vtblk_request_count--; 1296 free(req, M_DEVBUF); 1297 } 1298 1299 KASSERT(sc->vtblk_request_count == 0, 1300 ("%s: leaked %d requests", __func__, sc->vtblk_request_count)); 1301} 1302 1303static struct vtblk_request * 1304vtblk_dequeue_request(struct vtblk_softc *sc) 1305{ 1306 struct vtblk_request *req; 1307 1308 req = TAILQ_FIRST(&sc->vtblk_req_free); 1309 if (req != NULL) 1310 TAILQ_REMOVE(&sc->vtblk_req_free, req, vbr_link); 1311 1312 return (req); 1313} 1314 1315static void 1316vtblk_enqueue_request(struct vtblk_softc *sc, struct vtblk_request *req) 1317{ 1318 1319 bzero(req, sizeof(struct vtblk_request)); 1320 TAILQ_INSERT_HEAD(&sc->vtblk_req_free, req, vbr_link); 1321} 1322 1323static struct vtblk_request * 1324vtblk_dequeue_ready(struct vtblk_softc *sc) 1325{ 1326 struct vtblk_request *req; 1327 1328 req = TAILQ_FIRST(&sc->vtblk_req_ready); 1329 if (req != NULL) 1330 TAILQ_REMOVE(&sc->vtblk_req_ready, req, vbr_link); 1331 1332 return (req); 1333} 1334 1335static void 1336vtblk_enqueue_ready(struct vtblk_softc *sc, struct vtblk_request *req) 1337{ 1338 1339 TAILQ_INSERT_HEAD(&sc->vtblk_req_ready, req, vbr_link); 1340} 1341 1342static int 1343vtblk_request_error(struct vtblk_request *req) 1344{ 1345 int error; 1346 1347 switch (req->vbr_ack) { 1348 case VIRTIO_BLK_S_OK: 1349 error = 0; 1350 break; 1351 case VIRTIO_BLK_S_UNSUPP: 1352 error = ENOTSUP; 1353 break; 1354 default: 1355 error = EIO; 1356 break; 1357 } 1358 1359 return (error); 1360} 1361 1362static void 1363vtblk_finish_bio(struct bio *bp, int error) 1364{ 1365 1366 if (error) { 1367 bp->bio_resid = bp->bio_bcount; 1368 bp->bio_error = error; 1369 bp->bio_flags |= BIO_ERROR; 1370 } 1371 1372 biodone(bp); 1373} 1374 1375static void 1376vtblk_setup_sysctl(struct vtblk_softc *sc) 1377{ 1378 device_t dev; 1379 struct sysctl_ctx_list *ctx; 1380 struct sysctl_oid *tree; 1381 struct sysctl_oid_list *child; 1382 1383 dev = sc->vtblk_dev; 1384 ctx = device_get_sysctl_ctx(dev); 1385 tree = device_get_sysctl_tree(dev); 1386 child = SYSCTL_CHILDREN(tree); 1387 1388 SYSCTL_ADD_PROC(ctx, child, OID_AUTO, "writecache_mode", 1389 CTLTYPE_INT | CTLFLAG_RW, sc, 0, vtblk_write_cache_sysctl, 1390 "I", "Write cache mode (writethrough (0) or writeback (1))"); 1391} 1392 1393static int 1394vtblk_tunable_int(struct vtblk_softc *sc, const char *knob, int def) 1395{ 1396 char path[64]; 1397 1398 snprintf(path, sizeof(path), 1399 "hw.vtblk.%d.%s", device_get_unit(sc->vtblk_dev), knob); 1400 TUNABLE_INT_FETCH(path, &def); 1401 1402 return (def); 1403} 1404