1 /* $NetBSD: subr_devsw.c,v 1.55 2026/01/04 03:15:58 riastradh Exp $ */ 2 3 /*- 4 * Copyright (c) 2001, 2002, 2007, 2008 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by MAEKAWA Masahide <gehenna (at) NetBSD.org>, and by Andrew Doran. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 /* 33 * Overview 34 * 35 * subr_devsw.c: registers device drivers by name and by major 36 * number, and provides wrapper methods for performing I/O and 37 * other tasks on device drivers, keying on the device number 38 * (dev_t). 39 * 40 * When the system is built, the config(8) command generates 41 * static tables of device drivers built into the kernel image 42 * along with their associated methods. These are recorded in 43 * the cdevsw0 and bdevsw0 tables. Drivers can also be added to 44 * and removed from the system dynamically. 45 * 46 * Allocation 47 * 48 * When the system initially boots only the statically allocated 49 * indexes (bdevsw0, cdevsw0) are used. If these overflow due to 50 * allocation, we allocate a fixed block of memory to hold the new, 51 * expanded index. This "fork" of the table is only ever performed 52 * once in order to guarantee that other threads may safely access 53 * the device tables: 54 * 55 * o Once a thread has a "reference" to the table via an earlier 56 * open() call, we know that the entry in the table must exist 57 * and so it is safe to access it. 58 * 59 * o Regardless of whether other threads see the old or new 60 * pointers, they will point to a correct device switch 61 * structure for the operation being performed. 62 * 63 * XXX Currently, the wrapper methods such as cdev_read() verify 64 * that a device driver does in fact exist before calling the 65 * associated driver method. This should be changed so that 66 * once the device is has been referenced by a vnode (opened), 67 * calling the other methods should be valid until that reference 68 * is dropped. 69 */ 70 71 #include <sys/cdefs.h> 72 __KERNEL_RCSID(0, "$NetBSD: subr_devsw.c,v 1.55 2026/01/04 03:15:58 riastradh Exp $"); 73 74 #ifdef _KERNEL_OPT 75 #include "opt_dtrace.h" 76 #endif 77 78 #include <sys/param.h> 79 #include <sys/types.h> 80 81 #include <sys/atomic.h> 82 #include <sys/buf.h> 83 #include <sys/conf.h> 84 #include <sys/cpu.h> 85 #include <sys/device.h> 86 #include <sys/kmem.h> 87 #include <sys/localcount.h> 88 #include <sys/poll.h> 89 #include <sys/pserialize.h> 90 #include <sys/reboot.h> 91 #include <sys/sdt.h> 92 #include <sys/systm.h> 93 #include <sys/tty.h> 94 #include <sys/xcall.h> 95 96 #ifdef DEVSW_DEBUG 97 #define DPRINTF(x) printf x 98 #else /* DEVSW_DEBUG */ 99 #define DPRINTF(x) 100 #endif /* DEVSW_DEBUG */ 101 102 #define MAXDEVSW 512 /* the maximum of major device number */ 103 #define BDEVSW_SIZE (sizeof(struct bdevsw *)) 104 #define CDEVSW_SIZE (sizeof(struct cdevsw *)) 105 #define DEVSWCONV_SIZE (sizeof(struct devsw_conv)) 106 107 struct devswref { 108 struct localcount *dr_lc; 109 }; 110 111 /* XXX bdevsw, cdevsw, max_bdevsws, and max_cdevsws should be volatile */ 112 extern const struct bdevsw **bdevsw, *bdevsw0[]; 113 extern const struct cdevsw **cdevsw, *cdevsw0[]; 114 extern struct devsw_conv *devsw_conv, devsw_conv0[]; 115 extern const int sys_bdevsws, sys_cdevsws; 116 extern int max_bdevsws, max_cdevsws, max_devsw_convs; 117 118 static struct devswref *cdevswref; 119 static struct devswref *bdevswref; 120 static kcondvar_t devsw_cv; 121 122 static int bdevsw_attach(const struct bdevsw *, devmajor_t *); 123 static int cdevsw_attach(const struct cdevsw *, devmajor_t *); 124 static void devsw_detach_locked(const struct bdevsw *, const struct cdevsw *); 125 126 kmutex_t device_lock; 127 128 void (*biodone_vfs)(buf_t *) = (void *)nullop; 129 130 /* 131 * bdev probes 132 */ 133 SDT_PROBE_DEFINE6(sdt, bdev, open, acquire, 134 "struct bdevsw *"/*bdevsw*/, 135 "dev_t"/*dev*/, 136 "int"/*flag*/, 137 "int"/*devtype*/, 138 "int"/*unit*/, 139 "device_t"/*dv*/); 140 SDT_PROBE_DEFINE4(sdt, bdev, open, entry, 141 "struct bdevsw *"/*bdevsw*/, 142 "dev_t"/*dev*/, 143 "int"/*flag*/, 144 "int"/*devtype*/); 145 SDT_PROBE_DEFINE5(sdt, bdev, open, return, 146 "struct bdevsw *"/*bdevsw*/, 147 "dev_t"/*dev*/, 148 "int"/*flag*/, 149 "int"/*devtype*/, 150 "int"/*error*/); 151 SDT_PROBE_DEFINE6(sdt, bdev, open, release, 152 "struct bdevsw *"/*bdevsw*/, 153 "dev_t"/*dev*/, 154 "int"/*flag*/, 155 "int"/*devtype*/, 156 "int"/*unit*/, 157 "device_t"/*dv*/); 158 159 SDT_PROBE_DEFINE4(sdt, bdev, cancel, entry, 160 "struct bdevsw *"/*bdevsw*/, 161 "dev_t"/*dev*/, 162 "int"/*flag*/, 163 "int"/*devtype*/); 164 SDT_PROBE_DEFINE5(sdt, bdev, cancel, return, 165 "struct bdevsw *"/*bdevsw*/, 166 "dev_t"/*dev*/, 167 "int"/*flag*/, 168 "int"/*devtype*/, 169 "int"/*error*/); 170 171 SDT_PROBE_DEFINE4(sdt, bdev, close, entry, 172 "struct bdevsw *"/*bdevsw*/, 173 "dev_t"/*dev*/, 174 "int"/*flag*/, 175 "int"/*devtype*/); 176 SDT_PROBE_DEFINE5(sdt, bdev, close, return, 177 "struct bdevsw *"/*bdevsw*/, 178 "dev_t"/*dev*/, 179 "int"/*flag*/, 180 "int"/*devtype*/, 181 "int"/*error*/); 182 183 SDT_PROBE_DEFINE3(sdt, bdev, strategy, entry, 184 "struct bdevsw *"/*bdevsw*/, 185 "dev_t"/*dev*/, 186 "struct buf *"/*bp*/); 187 SDT_PROBE_DEFINE3(sdt, bdev, strategy, return, 188 "struct bdevsw *"/*bdevsw*/, 189 "dev_t"/*dev*/, 190 "struct buf *"/*bp*/); 191 192 SDT_PROBE_DEFINE5(sdt, bdev, ioctl, entry, 193 "struct bdevsw *"/*bdevsw*/, 194 "dev_t"/*dev*/, 195 "unsigned long"/*cmd*/, 196 "void *"/*data*/, 197 "int"/*flag*/); 198 SDT_PROBE_DEFINE6(sdt, bdev, ioctl, return, 199 "struct bdevsw *"/*bdevsw*/, 200 "dev_t"/*dev*/, 201 "unsigned long"/*cmd*/, 202 "void *"/*data*/, 203 "int"/*flag*/, 204 "int"/*error*/); 205 206 SDT_PROBE_DEFINE2(sdt, bdev, psize, entry, 207 "struct bdevsw *"/*bdevsw*/, 208 "dev_t"/*dev*/); 209 SDT_PROBE_DEFINE3(sdt, bdev, psize, return, 210 "struct bdevsw *"/*bdevsw*/, 211 "dev_t"/*dev*/, 212 "int"/*psize*/); 213 214 SDT_PROBE_DEFINE4(sdt, bdev, discard, entry, 215 "struct bdevsw *"/*bdevsw*/, 216 "dev_t"/*dev*/, 217 "off_t"/*pos*/, 218 "off_t"/*len*/); 219 SDT_PROBE_DEFINE5(sdt, bdev, discard, return, 220 "struct bdevsw *"/*bdevsw*/, 221 "dev_t"/*dev*/, 222 "off_t"/*pos*/, 223 "off_t"/*len*/, 224 "int"/*error*/); 225 226 /* 227 * cdev probes 228 */ 229 SDT_PROBE_DEFINE6(sdt, cdev, open, acquire, 230 "struct cdevsw *"/*cdevsw*/, 231 "dev_t"/*dev*/, 232 "int"/*flag*/, 233 "int"/*devtype*/, 234 "int"/*unit*/, 235 "device_t"/*dv*/); 236 SDT_PROBE_DEFINE4(sdt, cdev, open, entry, 237 "struct cdevsw *"/*cdevsw*/, 238 "dev_t"/*dev*/, 239 "int"/*flag*/, 240 "int"/*devtype*/); 241 SDT_PROBE_DEFINE5(sdt, cdev, open, return, 242 "struct cdevsw *"/*cdevsw*/, 243 "dev_t"/*dev*/, 244 "int"/*flag*/, 245 "int"/*devtype*/, 246 "int"/*error*/); 247 SDT_PROBE_DEFINE6(sdt, cdev, open, release, 248 "struct cdevsw *"/*cdevsw*/, 249 "dev_t"/*dev*/, 250 "int"/*flag*/, 251 "int"/*devtype*/, 252 "int"/*unit*/, 253 "device_t"/*dv*/); 254 255 SDT_PROBE_DEFINE4(sdt, cdev, cancel, entry, 256 "struct cdevsw *"/*cdevsw*/, 257 "dev_t"/*dev*/, 258 "int"/*flag*/, 259 "int"/*devtype*/); 260 SDT_PROBE_DEFINE5(sdt, cdev, cancel, return, 261 "struct cdevsw *"/*cdevsw*/, 262 "dev_t"/*dev*/, 263 "int"/*flag*/, 264 "int"/*devtype*/, 265 "int"/*error*/); 266 267 SDT_PROBE_DEFINE4(sdt, cdev, close, entry, 268 "struct cdevsw *"/*cdevsw*/, 269 "dev_t"/*dev*/, 270 "int"/*flag*/, 271 "int"/*devtype*/); 272 SDT_PROBE_DEFINE5(sdt, cdev, close, return, 273 "struct cdevsw *"/*cdevsw*/, 274 "dev_t"/*dev*/, 275 "int"/*flag*/, 276 "int"/*devtype*/, 277 "int"/*error*/); 278 279 SDT_PROBE_DEFINE4(sdt, cdev, read, entry, 280 "struct cdevsw *"/*cdevsw*/, 281 "dev_t"/*dev*/, 282 "struct uio *"/*uio*/, 283 "int"/*flag*/); 284 SDT_PROBE_DEFINE5(sdt, cdev, read, return, 285 "struct cdevsw *"/*cdevsw*/, 286 "dev_t"/*dev*/, 287 "struct uio *"/*uio*/, 288 "int"/*flag*/, 289 "int"/*error*/); 290 291 SDT_PROBE_DEFINE4(sdt, cdev, write, entry, 292 "struct cdevsw *"/*cdevsw*/, 293 "dev_t"/*dev*/, 294 "struct uio *"/*uio*/, 295 "int"/*flag*/); 296 SDT_PROBE_DEFINE5(sdt, cdev, write, return, 297 "struct cdevsw *"/*cdevsw*/, 298 "dev_t"/*dev*/, 299 "struct uio *"/*uio*/, 300 "int"/*flag*/, 301 "int"/*error*/); 302 303 SDT_PROBE_DEFINE5(sdt, cdev, ioctl, entry, 304 "struct cdevsw *"/*cdevsw*/, 305 "dev_t"/*dev*/, 306 "unsigned long"/*cmd*/, 307 "void *"/*data*/, 308 "int"/*flag*/); 309 SDT_PROBE_DEFINE6(sdt, cdev, ioctl, return, 310 "struct cdevsw *"/*cdevsw*/, 311 "dev_t"/*dev*/, 312 "unsigned long"/*cmd*/, 313 "void *"/*data*/, 314 "int"/*flag*/, 315 "int"/*error*/); 316 317 SDT_PROBE_DEFINE4(sdt, cdev, stop, entry, 318 "struct cdevsw *"/*cdevsw*/, 319 "dev_t"/*dev*/, 320 "struct tty *"/*tp*/, 321 "int"/*flag*/); 322 SDT_PROBE_DEFINE4(sdt, cdev, stop, return, 323 "struct cdevsw *"/*cdevsw*/, 324 "dev_t"/*dev*/, 325 "struct tty *"/*tp*/, 326 "int"/*flag*/); 327 328 SDT_PROBE_DEFINE3(sdt, cdev, poll, entry, 329 "struct cdevsw *"/*cdevsw*/, 330 "dev_t"/*dev*/, 331 "int"/*events*/); 332 SDT_PROBE_DEFINE4(sdt, cdev, poll, return, 333 "struct cdevsw *"/*cdevsw*/, 334 "dev_t"/*dev*/, 335 "int"/*events*/, 336 "int"/*revents*/); 337 338 SDT_PROBE_DEFINE4(sdt, cdev, mmap, entry, 339 "struct cdevsw *"/*cdevsw*/, 340 "dev_t"/*dev*/, 341 "off_t"/*off*/, 342 "int"/*flag*/); 343 SDT_PROBE_DEFINE5(sdt, cdev, mmap, return, 344 "struct cdevsw *"/*cdevsw*/, 345 "dev_t"/*dev*/, 346 "off_t"/*off*/, 347 "int"/*flag*/, 348 "paddr_t"/*mmapcookie*/); 349 350 SDT_PROBE_DEFINE3(sdt, cdev, kqfilter, entry, 351 "struct cdevsw *"/*cdevsw*/, 352 "dev_t"/*dev*/, 353 "struct knote *"/*kn*/); 354 SDT_PROBE_DEFINE4(sdt, cdev, kqfilter, return, 355 "struct cdevsw *"/*cdevsw*/, 356 "dev_t"/*dev*/, 357 "struct knote *"/*kn*/, 358 "int"/*error*/); 359 360 SDT_PROBE_DEFINE4(sdt, cdev, discard, entry, 361 "struct cdevsw *"/*cdevsw*/, 362 "dev_t"/*dev*/, 363 "off_t"/*pos*/, 364 "off_t"/*len*/); 365 SDT_PROBE_DEFINE5(sdt, cdev, discard, return, 366 "struct cdevsw *"/*cdevsw*/, 367 "dev_t"/*dev*/, 368 "off_t"/*pos*/, 369 "off_t"/*len*/, 370 "int"/*error*/); 371 372 void 373 devsw_init(void) 374 { 375 376 KASSERT(sys_bdevsws < MAXDEVSW - 1); 377 KASSERT(sys_cdevsws < MAXDEVSW - 1); 378 mutex_init(&device_lock, MUTEX_DEFAULT, IPL_NONE); 379 380 cv_init(&devsw_cv, "devsw"); 381 } 382 383 int 384 devsw_attach(const char *devname, 385 const struct bdevsw *bdev, devmajor_t *bmajor, 386 const struct cdevsw *cdev, devmajor_t *cmajor) 387 { 388 struct devsw_conv *conv; 389 char *name; 390 int error, i; 391 392 if (devname == NULL || cdev == NULL) 393 return SET_ERROR(EINVAL); 394 395 mutex_enter(&device_lock); 396 397 for (i = 0; i < max_devsw_convs; i++) { 398 conv = &devsw_conv[i]; 399 if (conv->d_name == NULL || strcmp(devname, conv->d_name) != 0) 400 continue; 401 402 if ((bdev != NULL) && (*bmajor < 0)) 403 *bmajor = conv->d_bmajor; 404 if (*cmajor < 0) 405 *cmajor = conv->d_cmajor; 406 407 if (*bmajor != conv->d_bmajor || *cmajor != conv->d_cmajor) { 408 error = SET_ERROR(EINVAL); 409 goto out; 410 } 411 if ((*bmajor >= 0 && bdev == NULL) || *cmajor < 0) { 412 error = SET_ERROR(EINVAL); 413 goto out; 414 } 415 416 if ((*bmajor >= 0 && bdevsw[*bmajor] != NULL) || 417 cdevsw[*cmajor] != NULL) { 418 error = SET_ERROR(EEXIST); 419 goto out; 420 } 421 break; 422 } 423 424 /* 425 * XXX This should allocate what it needs up front so we never 426 * need to flail around trying to unwind. 427 */ 428 error = bdevsw_attach(bdev, bmajor); 429 if (error != 0) 430 goto out; 431 error = cdevsw_attach(cdev, cmajor); 432 if (error != 0) { 433 devsw_detach_locked(bdev, NULL); 434 goto out; 435 } 436 437 /* 438 * If we already found a conv, we're done. Otherwise, find an 439 * empty slot or extend the table. 440 */ 441 if (i < max_devsw_convs) { 442 error = 0; 443 goto out; 444 } 445 446 for (i = 0; i < max_devsw_convs; i++) { 447 if (devsw_conv[i].d_name == NULL) 448 break; 449 } 450 if (i == max_devsw_convs) { 451 struct devsw_conv *newptr; 452 int old_convs, new_convs; 453 454 old_convs = max_devsw_convs; 455 new_convs = old_convs + 1; 456 457 newptr = kmem_zalloc(new_convs * DEVSWCONV_SIZE, KM_NOSLEEP); 458 if (newptr == NULL) { 459 devsw_detach_locked(bdev, cdev); 460 error = SET_ERROR(ENOMEM); 461 goto out; 462 } 463 newptr[old_convs].d_name = NULL; 464 newptr[old_convs].d_bmajor = -1; 465 newptr[old_convs].d_cmajor = -1; 466 memcpy(newptr, devsw_conv, old_convs * DEVSWCONV_SIZE); 467 if (devsw_conv != devsw_conv0) 468 kmem_free(devsw_conv, old_convs * DEVSWCONV_SIZE); 469 devsw_conv = newptr; 470 max_devsw_convs = new_convs; 471 } 472 473 name = kmem_strdupsize(devname, NULL, KM_NOSLEEP); 474 if (name == NULL) { 475 devsw_detach_locked(bdev, cdev); 476 error = SET_ERROR(ENOMEM); 477 goto out; 478 } 479 480 devsw_conv[i].d_name = name; 481 devsw_conv[i].d_bmajor = *bmajor; 482 devsw_conv[i].d_cmajor = *cmajor; 483 error = 0; 484 out: 485 mutex_exit(&device_lock); 486 return error; 487 } 488 489 static int 490 bdevsw_attach(const struct bdevsw *devsw, devmajor_t *devmajor) 491 { 492 const struct bdevsw **newbdevsw = NULL; 493 struct devswref *newbdevswref = NULL; 494 struct localcount *lc; 495 devmajor_t bmajor; 496 int i; 497 498 KASSERT(mutex_owned(&device_lock)); 499 500 if (devsw == NULL) 501 return 0; 502 503 if (*devmajor < 0) { 504 for (bmajor = sys_bdevsws; bmajor < max_bdevsws; bmajor++) { 505 if (bdevsw[bmajor] != NULL) 506 continue; 507 for (i = 0; i < max_devsw_convs; i++) { 508 if (devsw_conv[i].d_bmajor == bmajor) 509 break; 510 } 511 if (i != max_devsw_convs) 512 continue; 513 break; 514 } 515 *devmajor = bmajor; 516 } 517 518 if (*devmajor >= MAXDEVSW) { 519 printf("%s: block majors exhausted\n", __func__); 520 return SET_ERROR(ENOMEM); 521 } 522 523 if (bdevswref == NULL) { 524 newbdevswref = kmem_zalloc(MAXDEVSW * sizeof(newbdevswref[0]), 525 KM_NOSLEEP); 526 if (newbdevswref == NULL) 527 return SET_ERROR(ENOMEM); 528 atomic_store_release(&bdevswref, newbdevswref); 529 } 530 531 if (*devmajor >= max_bdevsws) { 532 KASSERT(bdevsw == bdevsw0); 533 newbdevsw = kmem_zalloc(MAXDEVSW * sizeof(newbdevsw[0]), 534 KM_NOSLEEP); 535 if (newbdevsw == NULL) 536 return SET_ERROR(ENOMEM); 537 memcpy(newbdevsw, bdevsw, max_bdevsws * sizeof(bdevsw[0])); 538 atomic_store_release(&bdevsw, newbdevsw); 539 atomic_store_release(&max_bdevsws, MAXDEVSW); 540 } 541 542 if (bdevsw[*devmajor] != NULL) 543 return SET_ERROR(EEXIST); 544 545 KASSERT(bdevswref[*devmajor].dr_lc == NULL); 546 lc = kmem_zalloc(sizeof(*lc), KM_SLEEP); 547 localcount_init(lc); 548 bdevswref[*devmajor].dr_lc = lc; 549 550 atomic_store_release(&bdevsw[*devmajor], devsw); 551 552 return 0; 553 } 554 555 static int 556 cdevsw_attach(const struct cdevsw *devsw, devmajor_t *devmajor) 557 { 558 const struct cdevsw **newcdevsw = NULL; 559 struct devswref *newcdevswref = NULL; 560 struct localcount *lc; 561 devmajor_t cmajor; 562 int i; 563 564 KASSERT(mutex_owned(&device_lock)); 565 566 if (*devmajor < 0) { 567 for (cmajor = sys_cdevsws; cmajor < max_cdevsws; cmajor++) { 568 if (cdevsw[cmajor] != NULL) 569 continue; 570 for (i = 0; i < max_devsw_convs; i++) { 571 if (devsw_conv[i].d_cmajor == cmajor) 572 break; 573 } 574 if (i != max_devsw_convs) 575 continue; 576 break; 577 } 578 *devmajor = cmajor; 579 } 580 581 if (*devmajor >= MAXDEVSW) { 582 printf("%s: character majors exhausted\n", __func__); 583 return SET_ERROR(ENOMEM); 584 } 585 586 if (cdevswref == NULL) { 587 newcdevswref = kmem_zalloc(MAXDEVSW * sizeof(newcdevswref[0]), 588 KM_NOSLEEP); 589 if (newcdevswref == NULL) 590 return SET_ERROR(ENOMEM); 591 atomic_store_release(&cdevswref, newcdevswref); 592 } 593 594 if (*devmajor >= max_cdevsws) { 595 KASSERT(cdevsw == cdevsw0); 596 newcdevsw = kmem_zalloc(MAXDEVSW * sizeof(newcdevsw[0]), 597 KM_NOSLEEP); 598 if (newcdevsw == NULL) 599 return SET_ERROR(ENOMEM); 600 memcpy(newcdevsw, cdevsw, max_cdevsws * sizeof(cdevsw[0])); 601 atomic_store_release(&cdevsw, newcdevsw); 602 atomic_store_release(&max_cdevsws, MAXDEVSW); 603 } 604 605 if (cdevsw[*devmajor] != NULL) 606 return SET_ERROR(EEXIST); 607 608 KASSERT(cdevswref[*devmajor].dr_lc == NULL); 609 lc = kmem_zalloc(sizeof(*lc), KM_SLEEP); 610 localcount_init(lc); 611 cdevswref[*devmajor].dr_lc = lc; 612 613 atomic_store_release(&cdevsw[*devmajor], devsw); 614 615 return 0; 616 } 617 618 static void 619 devsw_detach_locked(const struct bdevsw *bdev, const struct cdevsw *cdev) 620 { 621 int bi = -1, ci = -1/*XXXGCC*/, di; 622 struct cfdriver *cd; 623 device_t dv; 624 625 KASSERT(mutex_owned(&device_lock)); 626 627 /* 628 * If this is wired to an autoconf device, make sure the device 629 * has no more instances. No locking here because under 630 * correct use of devsw_detach, none of this state can change 631 * at this point. 632 */ 633 if (cdev != NULL && (cd = cdev->d_cfdriver) != NULL) { 634 for (di = 0; di < cd->cd_ndevs; di++) { 635 KASSERTMSG((dv = cd->cd_devs[di]) == NULL, 636 "detaching character device driver %s" 637 " still has attached unit %s", 638 cd->cd_name, device_xname(dv)); 639 } 640 } 641 if (bdev != NULL && (cd = bdev->d_cfdriver) != NULL) { 642 for (di = 0; di < cd->cd_ndevs; di++) { 643 KASSERTMSG((dv = cd->cd_devs[di]) == NULL, 644 "detaching block device driver %s" 645 " still has attached unit %s", 646 cd->cd_name, device_xname(dv)); 647 } 648 } 649 650 /* Prevent new references. */ 651 if (bdev != NULL) { 652 for (bi = 0; bi < max_bdevsws; bi++) { 653 if (bdevsw[bi] != bdev) 654 continue; 655 atomic_store_relaxed(&bdevsw[bi], NULL); 656 break; 657 } 658 KASSERT(bi < max_bdevsws); 659 } 660 if (cdev != NULL) { 661 for (ci = 0; ci < max_cdevsws; ci++) { 662 if (cdevsw[ci] != cdev) 663 continue; 664 atomic_store_relaxed(&cdevsw[ci], NULL); 665 break; 666 } 667 KASSERT(ci < max_cdevsws); 668 } 669 670 if (bdev == NULL && cdev == NULL) /* XXX possible? */ 671 return; 672 673 /* 674 * Wait for all bdevsw_lookup_acquire, cdevsw_lookup_acquire 675 * calls to notice that the devsw is gone. 676 * 677 * XXX Despite the use of the pserialize_read_enter/exit API 678 * elsewhere in this file, we use xc_barrier here instead of 679 * pserialize_perform -- because devsw_init is too early for 680 * pserialize_create. Either pserialize_create should be made 681 * to work earlier, or it should be nixed altogether. Until 682 * that is fixed, xc_barrier will serve the same purpose. 683 */ 684 xc_barrier(0); 685 686 /* 687 * Wait for all references to drain. It is the caller's 688 * responsibility to ensure that at this point, there are no 689 * extant open instances and all new d_open calls will fail. 690 * 691 * Note that localcount_drain may release and reacquire 692 * device_lock. 693 */ 694 if (bdev != NULL) { 695 localcount_drain(bdevswref[bi].dr_lc, 696 &devsw_cv, &device_lock); 697 localcount_fini(bdevswref[bi].dr_lc); 698 kmem_free(bdevswref[bi].dr_lc, sizeof(*bdevswref[bi].dr_lc)); 699 bdevswref[bi].dr_lc = NULL; 700 } 701 if (cdev != NULL) { 702 localcount_drain(cdevswref[ci].dr_lc, 703 &devsw_cv, &device_lock); 704 localcount_fini(cdevswref[ci].dr_lc); 705 kmem_free(cdevswref[ci].dr_lc, sizeof(*cdevswref[ci].dr_lc)); 706 cdevswref[ci].dr_lc = NULL; 707 } 708 } 709 710 void 711 devsw_detach(const struct bdevsw *bdev, const struct cdevsw *cdev) 712 { 713 714 mutex_enter(&device_lock); 715 devsw_detach_locked(bdev, cdev); 716 mutex_exit(&device_lock); 717 } 718 719 /* 720 * Look up a block device by number. 721 * 722 * => Caller must ensure that the device is attached. 723 */ 724 const struct bdevsw * 725 bdevsw_lookup(dev_t dev) 726 { 727 devmajor_t bmajor; 728 729 if (dev == NODEV) 730 return NULL; 731 bmajor = major(dev); 732 if (bmajor < 0 || bmajor >= atomic_load_relaxed(&max_bdevsws)) 733 return NULL; 734 735 return atomic_load_consume(&bdevsw)[bmajor]; 736 } 737 738 static const struct bdevsw * 739 bdevsw_lookup_acquire(dev_t dev, struct localcount **lcp) 740 { 741 devmajor_t bmajor; 742 const struct bdevsw *bdev = NULL, *const *curbdevsw; 743 struct devswref *curbdevswref; 744 int s; 745 746 if (dev == NODEV) 747 return NULL; 748 bmajor = major(dev); 749 if (bmajor < 0) 750 return NULL; 751 752 s = pserialize_read_enter(); 753 754 /* 755 * max_bdevsws never goes down, so it is safe to rely on this 756 * condition without any locking for the array access below. 757 * Test sys_bdevsws first so we can avoid the memory barrier in 758 * that case. 759 */ 760 if (bmajor >= sys_bdevsws && 761 bmajor >= atomic_load_acquire(&max_bdevsws)) 762 goto out; 763 curbdevsw = atomic_load_consume(&bdevsw); 764 if ((bdev = atomic_load_consume(&curbdevsw[bmajor])) == NULL) 765 goto out; 766 767 curbdevswref = atomic_load_consume(&bdevswref); 768 if (curbdevswref == NULL) { 769 *lcp = NULL; 770 } else if ((*lcp = curbdevswref[bmajor].dr_lc) != NULL) { 771 localcount_acquire(*lcp); 772 } 773 out: 774 pserialize_read_exit(s); 775 return bdev; 776 } 777 778 static void 779 bdevsw_release(const struct bdevsw *bdev, struct localcount *lc) 780 { 781 782 if (lc == NULL) 783 return; 784 localcount_release(lc, &devsw_cv, &device_lock); 785 } 786 787 /* 788 * Look up a character device by number. 789 * 790 * => Caller must ensure that the device is attached. 791 */ 792 const struct cdevsw * 793 cdevsw_lookup(dev_t dev) 794 { 795 devmajor_t cmajor; 796 797 if (dev == NODEV) 798 return NULL; 799 cmajor = major(dev); 800 if (cmajor < 0 || cmajor >= atomic_load_relaxed(&max_cdevsws)) 801 return NULL; 802 803 return atomic_load_consume(&cdevsw)[cmajor]; 804 } 805 806 static const struct cdevsw * 807 cdevsw_lookup_acquire(dev_t dev, struct localcount **lcp) 808 { 809 devmajor_t cmajor; 810 const struct cdevsw *cdev = NULL, *const *curcdevsw; 811 struct devswref *curcdevswref; 812 int s; 813 814 if (dev == NODEV) 815 return NULL; 816 cmajor = major(dev); 817 if (cmajor < 0) 818 return NULL; 819 820 s = pserialize_read_enter(); 821 822 /* 823 * max_cdevsws never goes down, so it is safe to rely on this 824 * condition without any locking for the array access below. 825 * Test sys_cdevsws first so we can avoid the memory barrier in 826 * that case. 827 */ 828 if (cmajor >= sys_cdevsws && 829 cmajor >= atomic_load_acquire(&max_cdevsws)) 830 goto out; 831 curcdevsw = atomic_load_consume(&cdevsw); 832 if ((cdev = atomic_load_consume(&curcdevsw[cmajor])) == NULL) 833 goto out; 834 835 curcdevswref = atomic_load_consume(&cdevswref); 836 if (curcdevswref == NULL) { 837 *lcp = NULL; 838 } else if ((*lcp = curcdevswref[cmajor].dr_lc) != NULL) { 839 localcount_acquire(*lcp); 840 } 841 out: 842 pserialize_read_exit(s); 843 return cdev; 844 } 845 846 static void 847 cdevsw_release(const struct cdevsw *cdev, struct localcount *lc) 848 { 849 850 if (lc == NULL) 851 return; 852 localcount_release(lc, &devsw_cv, &device_lock); 853 } 854 855 /* 856 * Look up a block device by reference to its operations set. 857 * 858 * => Caller must ensure that the device is not detached, and therefore 859 * that the returned major is still valid when dereferenced. 860 */ 861 devmajor_t 862 bdevsw_lookup_major(const struct bdevsw *bdev) 863 { 864 const struct bdevsw *const *curbdevsw; 865 devmajor_t bmajor, bmax; 866 867 bmax = atomic_load_acquire(&max_bdevsws); 868 curbdevsw = atomic_load_consume(&bdevsw); 869 for (bmajor = 0; bmajor < bmax; bmajor++) { 870 if (atomic_load_relaxed(&curbdevsw[bmajor]) == bdev) 871 return bmajor; 872 } 873 874 return NODEVMAJOR; 875 } 876 877 /* 878 * Look up a character device by reference to its operations set. 879 * 880 * => Caller must ensure that the device is not detached, and therefore 881 * that the returned major is still valid when dereferenced. 882 */ 883 devmajor_t 884 cdevsw_lookup_major(const struct cdevsw *cdev) 885 { 886 const struct cdevsw *const *curcdevsw; 887 devmajor_t cmajor, cmax; 888 889 cmax = atomic_load_acquire(&max_cdevsws); 890 curcdevsw = atomic_load_consume(&cdevsw); 891 for (cmajor = 0; cmajor < cmax; cmajor++) { 892 if (atomic_load_relaxed(&curcdevsw[cmajor]) == cdev) 893 return cmajor; 894 } 895 896 return NODEVMAJOR; 897 } 898 899 /* 900 * Convert from block major number to name. 901 * 902 * => Caller must ensure that the device is not detached, and therefore 903 * that the name pointer is still valid when dereferenced. 904 */ 905 const char * 906 devsw_blk2name(devmajor_t bmajor) 907 { 908 const char *name; 909 devmajor_t cmajor; 910 int i; 911 912 name = NULL; 913 cmajor = -1; 914 915 mutex_enter(&device_lock); 916 if (bmajor < 0 || bmajor >= max_bdevsws || bdevsw[bmajor] == NULL) { 917 mutex_exit(&device_lock); 918 return NULL; 919 } 920 for (i = 0; i < max_devsw_convs; i++) { 921 if (devsw_conv[i].d_bmajor == bmajor) { 922 cmajor = devsw_conv[i].d_cmajor; 923 break; 924 } 925 } 926 if (cmajor >= 0 && cmajor < max_cdevsws && cdevsw[cmajor] != NULL) 927 name = devsw_conv[i].d_name; 928 mutex_exit(&device_lock); 929 930 return name; 931 } 932 933 /* 934 * Convert char major number to device driver name. 935 */ 936 const char * 937 cdevsw_getname(devmajor_t major) 938 { 939 const char *name; 940 int i; 941 942 name = NULL; 943 944 if (major < 0) 945 return NULL; 946 947 mutex_enter(&device_lock); 948 for (i = 0; i < max_devsw_convs; i++) { 949 if (devsw_conv[i].d_cmajor == major) { 950 name = devsw_conv[i].d_name; 951 break; 952 } 953 } 954 mutex_exit(&device_lock); 955 return name; 956 } 957 958 /* 959 * Convert block major number to device driver name. 960 */ 961 const char * 962 bdevsw_getname(devmajor_t major) 963 { 964 const char *name; 965 int i; 966 967 name = NULL; 968 969 if (major < 0) 970 return NULL; 971 972 mutex_enter(&device_lock); 973 for (i = 0; i < max_devsw_convs; i++) { 974 if (devsw_conv[i].d_bmajor == major) { 975 name = devsw_conv[i].d_name; 976 break; 977 } 978 } 979 mutex_exit(&device_lock); 980 return name; 981 } 982 983 /* 984 * Convert from device name to block major number. 985 * 986 * => Caller must ensure that the device is not detached, and therefore 987 * that the major number is still valid when dereferenced. 988 */ 989 devmajor_t 990 devsw_name2blk(const char *name, char *devname, size_t devnamelen) 991 { 992 struct devsw_conv *conv; 993 devmajor_t bmajor; 994 int i; 995 996 if (name == NULL) 997 return NODEVMAJOR; 998 999 mutex_enter(&device_lock); 1000 for (i = 0; i < max_devsw_convs; i++) { 1001 size_t len; 1002 1003 conv = &devsw_conv[i]; 1004 if (conv->d_name == NULL) 1005 continue; 1006 len = strlen(conv->d_name); 1007 if (strncmp(conv->d_name, name, len) != 0) 1008 continue; 1009 if (name[len] != '\0' && !isdigit((unsigned char)name[len])) 1010 continue; 1011 bmajor = conv->d_bmajor; 1012 if (bmajor < 0 || bmajor >= max_bdevsws || 1013 bdevsw[bmajor] == NULL) 1014 break; 1015 if (devname != NULL) { 1016 #ifdef DEVSW_DEBUG 1017 if (strlen(conv->d_name) >= devnamelen) 1018 printf("%s: too short buffer\n", __func__); 1019 #endif /* DEVSW_DEBUG */ 1020 strncpy(devname, conv->d_name, devnamelen); 1021 devname[devnamelen - 1] = '\0'; 1022 } 1023 mutex_exit(&device_lock); 1024 return bmajor; 1025 } 1026 1027 mutex_exit(&device_lock); 1028 return NODEVMAJOR; 1029 } 1030 1031 /* 1032 * Convert from device name to char major number. 1033 * 1034 * => Caller must ensure that the device is not detached, and therefore 1035 * that the major number is still valid when dereferenced. 1036 */ 1037 devmajor_t 1038 devsw_name2chr(const char *name, char *devname, size_t devnamelen) 1039 { 1040 struct devsw_conv *conv; 1041 devmajor_t cmajor; 1042 int i; 1043 1044 if (name == NULL) 1045 return NODEVMAJOR; 1046 1047 mutex_enter(&device_lock); 1048 for (i = 0; i < max_devsw_convs; i++) { 1049 size_t len; 1050 1051 conv = &devsw_conv[i]; 1052 if (conv->d_name == NULL) 1053 continue; 1054 len = strlen(conv->d_name); 1055 if (strncmp(conv->d_name, name, len) != 0) 1056 continue; 1057 if (name[len] != '\0' && !isdigit((unsigned char)name[len])) 1058 continue; 1059 cmajor = conv->d_cmajor; 1060 if (cmajor < 0 || cmajor >= max_cdevsws || 1061 cdevsw[cmajor] == NULL) 1062 break; 1063 if (devname != NULL) { 1064 #ifdef DEVSW_DEBUG 1065 if (strlen(conv->d_name) >= devnamelen) 1066 printf("%s: too short buffer", __func__); 1067 #endif /* DEVSW_DEBUG */ 1068 strncpy(devname, conv->d_name, devnamelen); 1069 devname[devnamelen - 1] = '\0'; 1070 } 1071 mutex_exit(&device_lock); 1072 return cmajor; 1073 } 1074 1075 mutex_exit(&device_lock); 1076 return NODEVMAJOR; 1077 } 1078 1079 /* 1080 * Convert from character dev_t to block dev_t. 1081 * 1082 * => Caller must ensure that the device is not detached, and therefore 1083 * that the major number is still valid when dereferenced. 1084 */ 1085 dev_t 1086 devsw_chr2blk(dev_t cdev) 1087 { 1088 devmajor_t bmajor, cmajor; 1089 int i; 1090 dev_t rv; 1091 1092 cmajor = major(cdev); 1093 bmajor = NODEVMAJOR; 1094 rv = NODEV; 1095 1096 mutex_enter(&device_lock); 1097 if (cmajor < 0 || cmajor >= max_cdevsws || cdevsw[cmajor] == NULL) { 1098 mutex_exit(&device_lock); 1099 return NODEV; 1100 } 1101 for (i = 0; i < max_devsw_convs; i++) { 1102 if (devsw_conv[i].d_cmajor == cmajor) { 1103 bmajor = devsw_conv[i].d_bmajor; 1104 break; 1105 } 1106 } 1107 if (bmajor >= 0 && bmajor < max_bdevsws && bdevsw[bmajor] != NULL) 1108 rv = makedev(bmajor, minor(cdev)); 1109 mutex_exit(&device_lock); 1110 1111 return rv; 1112 } 1113 1114 /* 1115 * Convert from block dev_t to character dev_t. 1116 * 1117 * => Caller must ensure that the device is not detached, and therefore 1118 * that the major number is still valid when dereferenced. 1119 */ 1120 dev_t 1121 devsw_blk2chr(dev_t bdev) 1122 { 1123 devmajor_t bmajor, cmajor; 1124 int i; 1125 dev_t rv; 1126 1127 bmajor = major(bdev); 1128 cmajor = NODEVMAJOR; 1129 rv = NODEV; 1130 1131 mutex_enter(&device_lock); 1132 if (bmajor < 0 || bmajor >= max_bdevsws || bdevsw[bmajor] == NULL) { 1133 mutex_exit(&device_lock); 1134 return NODEV; 1135 } 1136 for (i = 0; i < max_devsw_convs; i++) { 1137 if (devsw_conv[i].d_bmajor == bmajor) { 1138 cmajor = devsw_conv[i].d_cmajor; 1139 break; 1140 } 1141 } 1142 if (cmajor >= 0 && cmajor < max_cdevsws && cdevsw[cmajor] != NULL) 1143 rv = makedev(cmajor, minor(bdev)); 1144 mutex_exit(&device_lock); 1145 1146 return rv; 1147 } 1148 1149 /* 1150 * Device access methods. 1151 */ 1152 1153 #define DEV_LOCK(d) \ 1154 if ((mpflag = (d->d_flag & D_MPSAFE)) == 0) { \ 1155 KERNEL_LOCK(1, NULL); \ 1156 } 1157 1158 #define DEV_UNLOCK(d) \ 1159 if (mpflag == 0) { \ 1160 KERNEL_UNLOCK_ONE(NULL); \ 1161 } 1162 1163 int 1164 bdev_open(dev_t dev, int flag, int devtype, lwp_t *l) 1165 { 1166 const struct bdevsw *d; 1167 struct localcount *lc; 1168 device_t dv = NULL/*XXXGCC*/; 1169 int unit = -1/*XXXGCC*/, rv, mpflag; 1170 1171 d = bdevsw_lookup_acquire(dev, &lc); 1172 if (d == NULL) 1173 return SET_ERROR(ENXIO); 1174 1175 if (d->d_devtounit) { 1176 /* 1177 * If the device node corresponds to an autoconf device 1178 * instance, acquire a reference to it so that during 1179 * d_open, device_lookup is stable. 1180 * 1181 * XXX This should also arrange to instantiate cloning 1182 * pseudo-devices if appropriate, but that requires 1183 * reviewing them all to find and verify a common 1184 * pattern. 1185 */ 1186 if ((unit = (*d->d_devtounit)(dev)) == -1) { 1187 rv = SET_ERROR(ENXIO); 1188 goto out; 1189 } 1190 if ((dv = device_lookup_acquire(d->d_cfdriver, unit)) == 1191 NULL) { 1192 rv = SET_ERROR(ENXIO); 1193 goto out; 1194 } 1195 SDT_PROBE6(sdt, bdev, open, acquire, 1196 d, dev, flag, devtype, unit, dv); 1197 } 1198 1199 DEV_LOCK(d); 1200 SDT_PROBE4(sdt, bdev, open, entry, d, dev, flag, devtype); 1201 rv = (*d->d_open)(dev, flag, devtype, l); 1202 SDT_PROBE5(sdt, bdev, open, return, d, dev, flag, devtype, rv); 1203 DEV_UNLOCK(d); 1204 1205 if (d->d_devtounit) { 1206 SDT_PROBE6(sdt, bdev, open, release, 1207 d, dev, flag, devtype, unit, dv); 1208 device_release(dv); 1209 } 1210 1211 out: bdevsw_release(d, lc); 1212 1213 return rv; 1214 } 1215 1216 int 1217 bdev_cancel(dev_t dev, int flag, int devtype, struct lwp *l) 1218 { 1219 const struct bdevsw *d; 1220 int rv, mpflag; 1221 1222 if ((d = bdevsw_lookup(dev)) == NULL) 1223 return SET_ERROR(ENXIO); 1224 if (d->d_cancel == NULL) 1225 return SET_ERROR(ENODEV); 1226 1227 DEV_LOCK(d); 1228 SDT_PROBE4(sdt, bdev, cancel, entry, d, dev, flag, devtype); 1229 rv = (*d->d_cancel)(dev, flag, devtype, l); 1230 SDT_PROBE5(sdt, bdev, cancel, return, d, dev, flag, devtype, rv); 1231 DEV_UNLOCK(d); 1232 1233 return rv; 1234 } 1235 1236 int 1237 bdev_close(dev_t dev, int flag, int devtype, lwp_t *l) 1238 { 1239 const struct bdevsw *d; 1240 int rv, mpflag; 1241 1242 if ((d = bdevsw_lookup(dev)) == NULL) 1243 return SET_ERROR(ENXIO); 1244 1245 DEV_LOCK(d); 1246 SDT_PROBE4(sdt, bdev, close, entry, d, dev, flag, devtype); 1247 rv = (*d->d_close)(dev, flag, devtype, l); 1248 SDT_PROBE5(sdt, bdev, close, return, d, dev, flag, devtype, rv); 1249 DEV_UNLOCK(d); 1250 1251 return rv; 1252 } 1253 1254 SDT_PROVIDER_DECLARE(io); 1255 SDT_PROBE_DEFINE1(io, kernel, , start, "struct buf *"/*bp*/); 1256 1257 void 1258 bdev_strategy(struct buf *bp) 1259 { 1260 const struct bdevsw *d; 1261 int mpflag; 1262 1263 SDT_PROBE1(io, kernel, , start, bp); 1264 1265 if ((d = bdevsw_lookup(bp->b_dev)) == NULL) { 1266 bp->b_error = SET_ERROR(ENXIO); 1267 bp->b_resid = bp->b_bcount; 1268 biodone_vfs(bp); /* biodone() iff vfs present */ 1269 return; 1270 } 1271 1272 DEV_LOCK(d); 1273 SDT_PROBE3(sdt, bdev, strategy, entry, d, bp->b_dev, bp); 1274 (*d->d_strategy)(bp); 1275 SDT_PROBE3(sdt, bdev, strategy, return, d, bp->b_dev, bp); 1276 DEV_UNLOCK(d); 1277 } 1278 1279 int 1280 bdev_ioctl(dev_t dev, u_long cmd, void *data, int flag, lwp_t *l) 1281 { 1282 const struct bdevsw *d; 1283 int rv, mpflag; 1284 1285 if ((d = bdevsw_lookup(dev)) == NULL) 1286 return SET_ERROR(ENXIO); 1287 1288 DEV_LOCK(d); 1289 SDT_PROBE5(sdt, bdev, ioctl, entry, d, dev, cmd, data, flag); 1290 rv = (*d->d_ioctl)(dev, cmd, data, flag, l); 1291 SDT_PROBE6(sdt, bdev, ioctl, return, d, dev, cmd, data, flag, rv); 1292 DEV_UNLOCK(d); 1293 1294 return rv; 1295 } 1296 1297 int 1298 bdev_dump(dev_t dev, daddr_t addr, void *data, size_t sz) 1299 { 1300 const struct bdevsw *d; 1301 int rv; 1302 1303 /* 1304 * Dump can be called without the device open. Since it can 1305 * currently only be called with the system paused (and in a 1306 * potentially unstable state), we don't perform any locking. 1307 */ 1308 if ((d = bdevsw_lookup(dev)) == NULL) 1309 return SET_ERROR(ENXIO); 1310 1311 /* DEV_LOCK(d); */ 1312 rv = (*d->d_dump)(dev, addr, data, sz); 1313 /* DEV_UNLOCK(d); */ 1314 1315 return rv; 1316 } 1317 1318 int 1319 bdev_flags(dev_t dev) 1320 { 1321 const struct bdevsw *d; 1322 1323 if ((d = bdevsw_lookup(dev)) == NULL) 1324 return 0; 1325 return d->d_flag & ~D_TYPEMASK; 1326 } 1327 1328 int 1329 bdev_type(dev_t dev) 1330 { 1331 const struct bdevsw *d; 1332 1333 if ((d = bdevsw_lookup(dev)) == NULL) 1334 return D_OTHER; 1335 return d->d_flag & D_TYPEMASK; 1336 } 1337 1338 int 1339 bdev_size(dev_t dev) 1340 { 1341 const struct bdevsw *d; 1342 int rv, mpflag = 0; 1343 1344 if ((d = bdevsw_lookup(dev)) == NULL || 1345 d->d_psize == NULL) 1346 return -1; 1347 1348 /* 1349 * Don't to try lock the device if we're dumping. 1350 * XXX: is there a better way to test this? 1351 */ 1352 if ((boothowto & RB_DUMP) == 0) 1353 DEV_LOCK(d); 1354 SDT_PROBE2(sdt, bdev, psize, entry, d, dev); 1355 rv = (*d->d_psize)(dev); 1356 SDT_PROBE3(sdt, bdev, psize, return, d, dev, rv); 1357 if ((boothowto & RB_DUMP) == 0) 1358 DEV_UNLOCK(d); 1359 1360 return rv; 1361 } 1362 1363 int 1364 bdev_discard(dev_t dev, off_t pos, off_t len) 1365 { 1366 const struct bdevsw *d; 1367 int rv, mpflag; 1368 1369 if ((d = bdevsw_lookup(dev)) == NULL) 1370 return SET_ERROR(ENXIO); 1371 1372 DEV_LOCK(d); 1373 SDT_PROBE4(sdt, bdev, discard, entry, d, dev, pos, len); 1374 rv = (*d->d_discard)(dev, pos, len); 1375 SDT_PROBE5(sdt, bdev, discard, return, d, dev, pos, len, rv); 1376 DEV_UNLOCK(d); 1377 1378 return rv; 1379 } 1380 1381 void 1382 bdev_detached(dev_t dev) 1383 { 1384 const struct bdevsw *d; 1385 device_t dv; 1386 int unit; 1387 1388 if ((d = bdevsw_lookup(dev)) == NULL) 1389 return; 1390 if (d->d_devtounit == NULL) 1391 return; 1392 if ((unit = (*d->d_devtounit)(dev)) == -1) 1393 return; 1394 if ((dv = device_lookup(d->d_cfdriver, unit)) == NULL) 1395 return; 1396 config_detach_commit(dv); 1397 } 1398 1399 int 1400 cdev_open(dev_t dev, int flag, int devtype, lwp_t *l) 1401 { 1402 const struct cdevsw *d; 1403 struct localcount *lc; 1404 device_t dv = NULL/*XXXGCC*/; 1405 int unit = -1/*XXXGCC*/, rv, mpflag; 1406 1407 d = cdevsw_lookup_acquire(dev, &lc); 1408 if (d == NULL) 1409 return SET_ERROR(ENXIO); 1410 1411 if (d->d_devtounit) { 1412 /* 1413 * If the device node corresponds to an autoconf device 1414 * instance, acquire a reference to it so that during 1415 * d_open, device_lookup is stable. 1416 * 1417 * XXX This should also arrange to instantiate cloning 1418 * pseudo-devices if appropriate, but that requires 1419 * reviewing them all to find and verify a common 1420 * pattern. 1421 */ 1422 if ((unit = (*d->d_devtounit)(dev)) == -1) { 1423 rv = SET_ERROR(ENXIO); 1424 goto out; 1425 } 1426 if ((dv = device_lookup_acquire(d->d_cfdriver, unit)) == 1427 NULL) { 1428 rv = SET_ERROR(ENXIO); 1429 goto out; 1430 } 1431 SDT_PROBE6(sdt, cdev, open, acquire, 1432 d, dev, flag, devtype, unit, dv); 1433 } 1434 1435 DEV_LOCK(d); 1436 SDT_PROBE4(sdt, cdev, open, entry, d, dev, flag, devtype); 1437 rv = (*d->d_open)(dev, flag, devtype, l); 1438 SDT_PROBE5(sdt, cdev, open, return, d, dev, flag, devtype, rv); 1439 DEV_UNLOCK(d); 1440 1441 if (d->d_devtounit) { 1442 SDT_PROBE6(sdt, cdev, open, release, 1443 d, dev, flag, devtype, unit, dv); 1444 device_release(dv); 1445 } 1446 1447 out: cdevsw_release(d, lc); 1448 1449 return rv; 1450 } 1451 1452 int 1453 cdev_cancel(dev_t dev, int flag, int devtype, struct lwp *l) 1454 { 1455 const struct cdevsw *d; 1456 int rv, mpflag; 1457 1458 if ((d = cdevsw_lookup(dev)) == NULL) 1459 return SET_ERROR(ENXIO); 1460 if (d->d_cancel == NULL) 1461 return SET_ERROR(ENODEV); 1462 1463 DEV_LOCK(d); 1464 SDT_PROBE4(sdt, cdev, cancel, entry, d, dev, flag, devtype); 1465 rv = (*d->d_cancel)(dev, flag, devtype, l); 1466 SDT_PROBE5(sdt, cdev, cancel, return, d, dev, flag, devtype, rv); 1467 DEV_UNLOCK(d); 1468 1469 return rv; 1470 } 1471 1472 int 1473 cdev_close(dev_t dev, int flag, int devtype, lwp_t *l) 1474 { 1475 const struct cdevsw *d; 1476 int rv, mpflag; 1477 1478 if ((d = cdevsw_lookup(dev)) == NULL) 1479 return SET_ERROR(ENXIO); 1480 1481 DEV_LOCK(d); 1482 SDT_PROBE4(sdt, cdev, close, entry, d, dev, flag, devtype); 1483 rv = (*d->d_close)(dev, flag, devtype, l); 1484 SDT_PROBE5(sdt, cdev, close, return, d, dev, flag, devtype, rv); 1485 DEV_UNLOCK(d); 1486 1487 return rv; 1488 } 1489 1490 int 1491 cdev_read(dev_t dev, struct uio *uio, int flag) 1492 { 1493 const struct cdevsw *d; 1494 int rv, mpflag; 1495 1496 if ((d = cdevsw_lookup(dev)) == NULL) 1497 return SET_ERROR(ENXIO); 1498 1499 DEV_LOCK(d); 1500 SDT_PROBE4(sdt, cdev, read, entry, d, dev, uio, flag); 1501 rv = (*d->d_read)(dev, uio, flag); 1502 SDT_PROBE5(sdt, cdev, read, return, d, dev, uio, flag, rv); 1503 DEV_UNLOCK(d); 1504 1505 return rv; 1506 } 1507 1508 int 1509 cdev_write(dev_t dev, struct uio *uio, int flag) 1510 { 1511 const struct cdevsw *d; 1512 int rv, mpflag; 1513 1514 if ((d = cdevsw_lookup(dev)) == NULL) 1515 return SET_ERROR(ENXIO); 1516 1517 DEV_LOCK(d); 1518 SDT_PROBE4(sdt, cdev, write, entry, d, dev, uio, flag); 1519 rv = (*d->d_write)(dev, uio, flag); 1520 SDT_PROBE5(sdt, cdev, write, return, d, dev, uio, flag, rv); 1521 DEV_UNLOCK(d); 1522 1523 return rv; 1524 } 1525 1526 int 1527 cdev_ioctl(dev_t dev, u_long cmd, void *data, int flag, lwp_t *l) 1528 { 1529 const struct cdevsw *d; 1530 int rv, mpflag; 1531 1532 if ((d = cdevsw_lookup(dev)) == NULL) 1533 return SET_ERROR(ENXIO); 1534 1535 DEV_LOCK(d); 1536 SDT_PROBE5(sdt, cdev, ioctl, entry, d, dev, cmd, data, flag); 1537 rv = (*d->d_ioctl)(dev, cmd, data, flag, l); 1538 SDT_PROBE6(sdt, cdev, ioctl, return, d, dev, cmd, data, flag, rv); 1539 DEV_UNLOCK(d); 1540 1541 return rv; 1542 } 1543 1544 void 1545 cdev_stop(struct tty *tp, int flag) 1546 { 1547 const struct cdevsw *d; 1548 int mpflag; 1549 1550 if ((d = cdevsw_lookup(tp->t_dev)) == NULL) 1551 return; 1552 1553 DEV_LOCK(d); 1554 SDT_PROBE4(sdt, cdev, stop, entry, d, tp->t_dev, tp, flag); 1555 (*d->d_stop)(tp, flag); 1556 SDT_PROBE4(sdt, cdev, stop, return, d, tp->t_dev, tp, flag); 1557 DEV_UNLOCK(d); 1558 } 1559 1560 struct tty * 1561 cdev_tty(dev_t dev) 1562 { 1563 const struct cdevsw *d; 1564 1565 if ((d = cdevsw_lookup(dev)) == NULL) 1566 return NULL; 1567 1568 /* XXX Check if necessary. */ 1569 if (d->d_tty == NULL) 1570 return NULL; 1571 1572 return (*d->d_tty)(dev); 1573 } 1574 1575 int 1576 cdev_poll(dev_t dev, int flag, lwp_t *l) 1577 { 1578 const struct cdevsw *d; 1579 int rv, mpflag; 1580 1581 if ((d = cdevsw_lookup(dev)) == NULL) 1582 return POLLERR; 1583 1584 DEV_LOCK(d); 1585 SDT_PROBE3(sdt, cdev, poll, entry, d, dev, flag); 1586 rv = (*d->d_poll)(dev, flag, l); 1587 SDT_PROBE4(sdt, cdev, poll, return, d, dev, flag, rv); 1588 DEV_UNLOCK(d); 1589 1590 return rv; 1591 } 1592 1593 paddr_t 1594 cdev_mmap(dev_t dev, off_t off, int flag) 1595 { 1596 const struct cdevsw *d; 1597 paddr_t rv; 1598 int mpflag; 1599 1600 if ((d = cdevsw_lookup(dev)) == NULL) 1601 return (paddr_t)-1LL; 1602 1603 DEV_LOCK(d); 1604 SDT_PROBE4(sdt, cdev, mmap, entry, d, dev, off, flag); 1605 rv = (*d->d_mmap)(dev, off, flag); 1606 SDT_PROBE5(sdt, cdev, mmap, return, d, dev, off, flag, rv); 1607 DEV_UNLOCK(d); 1608 1609 return rv; 1610 } 1611 1612 int 1613 cdev_kqfilter(dev_t dev, struct knote *kn) 1614 { 1615 const struct cdevsw *d; 1616 int rv, mpflag; 1617 1618 if ((d = cdevsw_lookup(dev)) == NULL) 1619 return SET_ERROR(ENXIO); 1620 1621 DEV_LOCK(d); 1622 SDT_PROBE3(sdt, cdev, kqfilter, entry, d, dev, kn); 1623 rv = (*d->d_kqfilter)(dev, kn); 1624 SDT_PROBE4(sdt, cdev, kqfilter, return, d, dev, kn, rv); 1625 DEV_UNLOCK(d); 1626 1627 return rv; 1628 } 1629 1630 int 1631 cdev_discard(dev_t dev, off_t pos, off_t len) 1632 { 1633 const struct cdevsw *d; 1634 int rv, mpflag; 1635 1636 if ((d = cdevsw_lookup(dev)) == NULL) 1637 return SET_ERROR(ENXIO); 1638 1639 DEV_LOCK(d); 1640 SDT_PROBE4(sdt, cdev, discard, entry, d, dev, pos, len); 1641 rv = (*d->d_discard)(dev, pos, len); 1642 SDT_PROBE5(sdt, cdev, discard, return, d, dev, pos, len, rv); 1643 DEV_UNLOCK(d); 1644 1645 return rv; 1646 } 1647 1648 int 1649 cdev_flags(dev_t dev) 1650 { 1651 const struct cdevsw *d; 1652 1653 if ((d = cdevsw_lookup(dev)) == NULL) 1654 return 0; 1655 return d->d_flag & ~D_TYPEMASK; 1656 } 1657 1658 int 1659 cdev_type(dev_t dev) 1660 { 1661 const struct cdevsw *d; 1662 1663 if ((d = cdevsw_lookup(dev)) == NULL) 1664 return D_OTHER; 1665 return d->d_flag & D_TYPEMASK; 1666 } 1667 1668 void 1669 cdev_detached(dev_t dev) 1670 { 1671 const struct cdevsw *d; 1672 device_t dv; 1673 int unit; 1674 1675 if ((d = cdevsw_lookup(dev)) == NULL) 1676 return; 1677 if (d->d_devtounit == NULL) 1678 return; 1679 if ((unit = (*d->d_devtounit)(dev)) == -1) 1680 return; 1681 if ((dv = device_lookup(d->d_cfdriver, unit)) == NULL) 1682 return; 1683 config_detach_commit(dv); 1684 } 1685 1686 /* 1687 * nommap(dev, off, prot) 1688 * 1689 * mmap routine that always fails, for non-mmappable devices. 1690 */ 1691 paddr_t 1692 nommap(dev_t dev, off_t off, int prot) 1693 { 1694 1695 return (paddr_t)-1; 1696 } 1697 1698 /* 1699 * dev_minor_unit(dev) 1700 * 1701 * Returns minor(dev) as an int. Intended for use with struct 1702 * bdevsw, cdevsw::d_devtounit for drivers whose /dev nodes are 1703 * implemented by reference to an autoconf instance with the minor 1704 * number. 1705 */ 1706 int 1707 dev_minor_unit(dev_t dev) 1708 { 1709 1710 return minor(dev); 1711 } 1712
Indexes created Sat Feb 21 16:20:20 UTC 2026