md.c revision 1.47
1 /* $NetBSD: md.c,v 1.47 2006/11/16 01:32:45 christos 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 * 3. The name of the author may not be used to endorse or promote products 16 * derived from this software without specific prior written permission. 17 * 4. All advertising materials mentioning features or use of this software 18 * must display the following acknowledgement: 19 * This product includes software developed by 20 * Gordon W. Ross and Leo Weppelman. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 23 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 24 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 25 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 26 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 27 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 28 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 29 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 30 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 31 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 32 */ 33 34 /* 35 * This implements a general-purpose memory-disk. 36 * See md.h for notes on the config types. 37 * 38 * Note that this driver provides the same functionality 39 * as the MFS filesystem hack, but this is better because 40 * you can use this for any filesystem type you'd like! 41 * 42 * Credit for most of the kmem ramdisk code goes to: 43 * Leo Weppelman (atari) and Phil Nelson (pc532) 44 * Credit for the ideas behind the "user space memory" code goes 45 * to the authors of the MFS implementation. 46 */ 47 48 #include <sys/cdefs.h> 49 __KERNEL_RCSID(0, "$NetBSD: md.c,v 1.47 2006/11/16 01:32:45 christos Exp $"); 50 51 #include "opt_md.h" 52 53 #include <sys/param.h> 54 #include <sys/kernel.h> 55 #include <sys/malloc.h> 56 #include <sys/systm.h> 57 #include <sys/buf.h> 58 #include <sys/bufq.h> 59 #include <sys/device.h> 60 #include <sys/disk.h> 61 #include <sys/proc.h> 62 #include <sys/conf.h> 63 #include <sys/disklabel.h> 64 65 #include <uvm/uvm_extern.h> 66 67 #include <dev/md.h> 68 69 /* 70 * By default, include the user-space functionality. 71 * Use `options MEMORY_DISK_SERVER=0' to turn it off. 72 */ 73 #ifndef MEMORY_DISK_SERVER 74 #define MEMORY_DISK_SERVER 1 75 #endif /* MEMORY_DISK_SERVER */ 76 77 /* 78 * We should use the raw partition for ioctl. 79 */ 80 #define MD_MAX_UNITS 0x10 81 #define MD_UNIT(unit) DISKUNIT(unit) 82 83 /* autoconfig stuff... */ 84 85 struct md_softc { 86 struct device sc_dev; /* REQUIRED first entry */ 87 struct disk sc_dkdev; /* hook for generic disk handling */ 88 struct md_conf sc_md; 89 struct bufq_state *sc_buflist; 90 }; 91 /* shorthand for fields in sc_md: */ 92 #define sc_addr sc_md.md_addr 93 #define sc_size sc_md.md_size 94 #define sc_type sc_md.md_type 95 96 void mdattach(int); 97 98 static void md_attach(struct device *, struct device *, void *); 99 100 static dev_type_open(mdopen); 101 static dev_type_close(mdclose); 102 static dev_type_read(mdread); 103 static dev_type_write(mdwrite); 104 static dev_type_ioctl(mdioctl); 105 static dev_type_strategy(mdstrategy); 106 static dev_type_size(mdsize); 107 108 const struct bdevsw md_bdevsw = { 109 mdopen, mdclose, mdstrategy, mdioctl, nodump, mdsize, D_DISK 110 }; 111 112 const struct cdevsw md_cdevsw = { 113 mdopen, mdclose, mdread, mdwrite, mdioctl, 114 nostop, notty, nopoll, nommap, nokqfilter, D_DISK 115 }; 116 117 static struct dkdriver mddkdriver = { mdstrategy, NULL }; 118 119 static int ramdisk_ndevs; 120 static void *ramdisk_devs[MD_MAX_UNITS]; 121 122 /* 123 * This is called if we are configured as a pseudo-device 124 */ 125 void 126 mdattach(int n) 127 { 128 struct md_softc *sc; 129 int i; 130 131 #ifdef DIAGNOSTIC 132 if (ramdisk_ndevs) { 133 aprint_error("ramdisk: multiple attach calls?\n"); 134 return; 135 } 136 #endif 137 138 /* XXX: Are we supposed to provide a default? */ 139 if (n <= 1) 140 n = 1; 141 if (n > MD_MAX_UNITS) 142 n = MD_MAX_UNITS; 143 ramdisk_ndevs = n; 144 145 /* Attach as if by autoconfig. */ 146 for (i = 0; i < n; i++) { 147 148 sc = malloc(sizeof(*sc), M_DEVBUF, M_NOWAIT|M_ZERO); 149 if (!sc) { 150 aprint_error("ramdisk: malloc for attach failed!\n"); 151 return; 152 } 153 ramdisk_devs[i] = sc; 154 sc->sc_dev.dv_unit = i; 155 snprintf(sc->sc_dev.dv_xname, sizeof(sc->sc_dev.dv_xname), 156 "md%d", i); 157 md_attach(NULL, &sc->sc_dev, NULL); 158 } 159 } 160 161 static void 162 md_attach(struct device *parent, struct device *self, 163 void *aux) 164 { 165 struct md_softc *sc = (struct md_softc *)self; 166 167 bufq_alloc(&sc->sc_buflist, "fcfs", 0); 168 169 /* XXX - Could accept aux info here to set the config. */ 170 #ifdef MEMORY_DISK_HOOKS 171 /* 172 * This external function might setup a pre-loaded disk. 173 * All it would need to do is setup the md_conf struct. 174 * See sys/dev/md_root.c for an example. 175 */ 176 md_attach_hook(device_unit(&sc->sc_dev), &sc->sc_md); 177 #endif 178 179 /* 180 * Initialize and attach the disk structure. 181 */ 182 sc->sc_dkdev.dk_driver = &mddkdriver; 183 sc->sc_dkdev.dk_name = sc->sc_dev.dv_xname; 184 disk_attach(&sc->sc_dkdev); 185 } 186 187 /* 188 * operational routines: 189 * open, close, read, write, strategy, 190 * ioctl, dump, size 191 */ 192 193 #if MEMORY_DISK_SERVER 194 static int md_server_loop(struct md_softc *sc); 195 static int md_ioctl_server(struct md_softc *sc, struct md_conf *umd, 196 struct lwp *l); 197 #endif /* MEMORY_DISK_SERVER */ 198 static int md_ioctl_kalloc(struct md_softc *sc, struct md_conf *umd, 199 struct lwp *l); 200 201 static int 202 mdsize(dev_t dev) 203 { 204 int unit; 205 struct md_softc *sc; 206 207 unit = MD_UNIT(dev); 208 if (unit >= ramdisk_ndevs) 209 return 0; 210 sc = ramdisk_devs[unit]; 211 if (sc == NULL) 212 return 0; 213 214 if (sc->sc_type == MD_UNCONFIGURED) 215 return 0; 216 217 return (sc->sc_size >> DEV_BSHIFT); 218 } 219 220 static int 221 mdopen(dev_t dev, int flag, int fmt, struct lwp *l) 222 { 223 int unit; 224 struct md_softc *sc; 225 226 unit = MD_UNIT(dev); 227 if (unit >= ramdisk_ndevs) 228 return ENXIO; 229 sc = ramdisk_devs[unit]; 230 if (sc == NULL) 231 return ENXIO; 232 233 /* 234 * The raw partition is used for ioctl to configure. 235 */ 236 if (DISKPART(dev) == RAW_PART) 237 return 0; 238 239 #ifdef MEMORY_DISK_HOOKS 240 /* Call the open hook to allow loading the device. */ 241 md_open_hook(unit, &sc->sc_md); 242 #endif 243 244 /* 245 * This is a normal, "slave" device, so 246 * enforce initialized. 247 */ 248 if (sc->sc_type == MD_UNCONFIGURED) 249 return ENXIO; 250 251 return 0; 252 } 253 254 static int 255 mdclose(dev_t dev, int flag, int fmt, struct lwp *l) 256 { 257 int unit; 258 259 unit = MD_UNIT(dev); 260 261 if (unit >= ramdisk_ndevs) 262 return ENXIO; 263 264 return 0; 265 } 266 267 static int 268 mdread(dev_t dev, struct uio *uio, int flags) 269 { 270 int unit; 271 struct md_softc *sc; 272 273 unit = MD_UNIT(dev); 274 275 if (unit >= ramdisk_ndevs) 276 return ENXIO; 277 278 sc = ramdisk_devs[unit]; 279 280 if (sc->sc_type == MD_UNCONFIGURED) 281 return ENXIO; 282 283 return (physio(mdstrategy, NULL, dev, B_READ, minphys, uio)); 284 } 285 286 static int 287 mdwrite(dev_t dev, struct uio *uio, int flags) 288 { 289 int unit; 290 struct md_softc *sc; 291 292 unit = MD_UNIT(dev); 293 294 if (unit >= ramdisk_ndevs) 295 return ENXIO; 296 297 sc = ramdisk_devs[unit]; 298 299 if (sc->sc_type == MD_UNCONFIGURED) 300 return ENXIO; 301 302 return (physio(mdstrategy, NULL, dev, B_WRITE, minphys, uio)); 303 } 304 305 /* 306 * Handle I/O requests, either directly, or 307 * by passing them to the server process. 308 */ 309 static void 310 mdstrategy(struct buf *bp) 311 { 312 int unit; 313 struct md_softc *sc; 314 caddr_t addr; 315 size_t off, xfer; 316 317 unit = MD_UNIT(bp->b_dev); 318 sc = ramdisk_devs[unit]; 319 320 if (sc->sc_type == MD_UNCONFIGURED) { 321 bp->b_error = ENXIO; 322 bp->b_flags |= B_ERROR; 323 goto done; 324 } 325 326 switch (sc->sc_type) { 327 #if MEMORY_DISK_SERVER 328 case MD_UMEM_SERVER: 329 /* Just add this job to the server's queue. */ 330 BUFQ_PUT(sc->sc_buflist, bp); 331 wakeup((caddr_t)sc); 332 /* see md_server_loop() */ 333 /* no biodone in this case */ 334 return; 335 #endif /* MEMORY_DISK_SERVER */ 336 337 case MD_KMEM_FIXED: 338 case MD_KMEM_ALLOCATED: 339 /* These are in kernel space. Access directly. */ 340 bp->b_resid = bp->b_bcount; 341 off = (bp->b_blkno << DEV_BSHIFT); 342 if (off >= sc->sc_size) { 343 if (bp->b_flags & B_READ) 344 break; /* EOF */ 345 goto set_eio; 346 } 347 xfer = bp->b_resid; 348 if (xfer > (sc->sc_size - off)) 349 xfer = (sc->sc_size - off); 350 addr = sc->sc_addr + off; 351 if (bp->b_flags & B_READ) 352 memcpy(bp->b_data, addr, xfer); 353 else 354 memcpy(addr, bp->b_data, xfer); 355 bp->b_resid -= xfer; 356 break; 357 358 default: 359 bp->b_resid = bp->b_bcount; 360 set_eio: 361 bp->b_error = EIO; 362 bp->b_flags |= B_ERROR; 363 break; 364 } 365 done: 366 biodone(bp); 367 } 368 369 static int 370 mdioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct lwp *l) 371 { 372 int unit; 373 struct md_softc *sc; 374 struct md_conf *umd; 375 376 unit = MD_UNIT(dev); 377 sc = ramdisk_devs[unit]; 378 379 /* If this is not the raw partition, punt! */ 380 if (DISKPART(dev) != RAW_PART) 381 return ENOTTY; 382 383 umd = (struct md_conf *)data; 384 switch (cmd) { 385 case MD_GETCONF: 386 *umd = sc->sc_md; 387 return 0; 388 389 case MD_SETCONF: 390 /* Can only set it once. */ 391 if (sc->sc_type != MD_UNCONFIGURED) 392 break; 393 switch (umd->md_type) { 394 case MD_KMEM_ALLOCATED: 395 return md_ioctl_kalloc(sc, umd, l); 396 #if MEMORY_DISK_SERVER 397 case MD_UMEM_SERVER: 398 return md_ioctl_server(sc, umd, l); 399 #endif /* MEMORY_DISK_SERVER */ 400 default: 401 break; 402 } 403 break; 404 } 405 return EINVAL; 406 } 407 408 /* 409 * Handle ioctl MD_SETCONF for (sc_type == MD_KMEM_ALLOCATED) 410 * Just allocate some kernel memory and return. 411 */ 412 static int 413 md_ioctl_kalloc(struct md_softc *sc, struct md_conf *umd, 414 struct lwp *l) 415 { 416 vaddr_t addr; 417 vsize_t size; 418 419 /* Sanity check the size. */ 420 size = umd->md_size; 421 addr = uvm_km_alloc(kernel_map, size, 0, UVM_KMF_WIRED|UVM_KMF_ZERO); 422 if (!addr) 423 return ENOMEM; 424 425 /* This unit is now configured. */ 426 sc->sc_addr = (caddr_t)addr; /* kernel space */ 427 sc->sc_size = (size_t)size; 428 sc->sc_type = MD_KMEM_ALLOCATED; 429 return 0; 430 } 431 432 #if MEMORY_DISK_SERVER 433 434 /* 435 * Handle ioctl MD_SETCONF for (sc_type == MD_UMEM_SERVER) 436 * Set config, then become the I/O server for this unit. 437 */ 438 static int 439 md_ioctl_server(struct md_softc *sc, struct md_conf *umd, 440 struct lwp *l) 441 { 442 vaddr_t end; 443 int error; 444 445 /* Sanity check addr, size. */ 446 end = (vaddr_t) (umd->md_addr + umd->md_size); 447 448 if ((end >= VM_MAXUSER_ADDRESS) || 449 (end < ((vaddr_t) umd->md_addr)) ) 450 return EINVAL; 451 452 /* This unit is now configured. */ 453 sc->sc_addr = umd->md_addr; /* user space */ 454 sc->sc_size = umd->md_size; 455 sc->sc_type = MD_UMEM_SERVER; 456 457 /* Become the server daemon */ 458 error = md_server_loop(sc); 459 460 /* This server is now going away! */ 461 sc->sc_type = MD_UNCONFIGURED; 462 sc->sc_addr = 0; 463 sc->sc_size = 0; 464 465 return (error); 466 } 467 468 static int md_sleep_pri = PWAIT | PCATCH; 469 470 static int 471 md_server_loop(struct md_softc *sc) 472 { 473 struct buf *bp; 474 caddr_t addr; /* user space address */ 475 size_t off; /* offset into "device" */ 476 size_t xfer; /* amount to transfer */ 477 int error; 478 479 for (;;) { 480 /* Wait for some work to arrive. */ 481 while ((bp = BUFQ_GET(sc->sc_buflist)) == NULL) { 482 error = tsleep((caddr_t)sc, md_sleep_pri, "md_idle", 0); 483 if (error) 484 return error; 485 } 486 487 /* Do the transfer to/from user space. */ 488 error = 0; 489 bp->b_resid = bp->b_bcount; 490 off = (bp->b_blkno << DEV_BSHIFT); 491 if (off >= sc->sc_size) { 492 if (bp->b_flags & B_READ) 493 goto done; /* EOF (not an error) */ 494 error = EIO; 495 goto done; 496 } 497 xfer = bp->b_resid; 498 if (xfer > (sc->sc_size - off)) 499 xfer = (sc->sc_size - off); 500 addr = sc->sc_addr + off; 501 if (bp->b_flags & B_READ) 502 error = copyin(addr, bp->b_data, xfer); 503 else 504 error = copyout(bp->b_data, addr, xfer); 505 if (!error) 506 bp->b_resid -= xfer; 507 508 done: 509 if (error) { 510 bp->b_error = error; 511 bp->b_flags |= B_ERROR; 512 } 513 biodone(bp); 514 } 515 } 516 #endif /* MEMORY_DISK_SERVER */ 517
Indexes created Thu Sep 25 16:09:42 GMT 2025