FreeBSD/Linux Kernel Cross Reference
sys/dev/md.c
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 */
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