xref: /netbsd/sys/dev/md.c (revision c4a72b64) 
1 /*	$NetBSD: md.c,v 1.32 2002/10/23 09:13:03 jdolecek 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 1.32 2002/10/23 09:13:03 jdolecek 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/device.h>
59 #include <sys/disk.h>
60 #include <sys/proc.h>
61 #include <sys/conf.h>
62 #include <sys/disklabel.h>
63 
64 #include <uvm/uvm_extern.h>
65 
66 #include <dev/md.h>
67 
68 /*
69  * By default, include the user-space functionality.
70  * Use  `options MEMORY_DISK_SERVER=0' to turn it off.
71  */
72 #ifndef MEMORY_DISK_SERVER
73 #define	MEMORY_DISK_SERVER 1
74 #endif
75 
76 /*
77  * We should use the raw partition for ioctl.
78  */
79 #define MD_MAX_UNITS	0x10
80 #define MD_UNIT(unit)	DISKUNIT(unit)
81 
82 /* autoconfig stuff... */
83 
84 struct md_softc {
85 	struct device sc_dev;	/* REQUIRED first entry */
86 	struct disk sc_dkdev;	/* hook for generic disk handling */
87 	struct md_conf sc_md;
88 	struct bufq_state sc_buflist;
89 };
90 /* shorthand for fields in sc_md: */
91 #define sc_addr sc_md.md_addr
92 #define sc_size sc_md.md_size
93 #define sc_type sc_md.md_type
94 
95 void mdattach __P((int));
96 static void md_attach __P((struct device *, struct device *, void *));
97 
98 dev_type_open(mdopen);
99 dev_type_close(mdclose);
100 dev_type_read(mdread);
101 dev_type_write(mdwrite);
102 dev_type_ioctl(mdioctl);
103 dev_type_strategy(mdstrategy);
104 dev_type_size(mdsize);
105 
106 const struct bdevsw md_bdevsw = {
107 	mdopen, mdclose, mdstrategy, mdioctl, nodump, mdsize, D_DISK
108 };
109 
110 const struct cdevsw md_cdevsw = {
111 	mdopen, mdclose, mdread, mdwrite, mdioctl,
112 	nostop, notty, nopoll, nommap, nokqfilter, D_DISK
113 };
114 
115 struct dkdriver mddkdriver = { mdstrategy };
116 
117 static int   ramdisk_ndevs;
118 static void *ramdisk_devs[MD_MAX_UNITS];
119 
120 /*
121  * This is called if we are configured as a pseudo-device
122  */
123 void
124 mdattach(n)
125 	int n;
126 {
127 	struct md_softc *sc;
128 	int i;
129 
130 #ifdef	DIAGNOSTIC
131 	if (ramdisk_ndevs) {
132 		printf("ramdisk: multiple attach calls?\n");
133 		return;
134 	}
135 #endif
136 
137 	/* XXX:  Are we supposed to provide a default? */
138 	if (n <= 1)
139 		n = 1;
140 	if (n > MD_MAX_UNITS)
141 		n = MD_MAX_UNITS;
142 	ramdisk_ndevs = n;
143 
144 	/* Attach as if by autoconfig. */
145 	for (i = 0; i < n; i++) {
146 
147 		sc = malloc(sizeof(*sc), M_DEVBUF, M_NOWAIT|M_ZERO);
148 		if (!sc) {
149 			printf("ramdisk: malloc for attach failed!\n");
150 			return;
151 		}
152 		ramdisk_devs[i] = sc;
153 		sc->sc_dev.dv_unit = i;
154 		sprintf(sc->sc_dev.dv_xname, "md%d", i);
155 		md_attach(NULL, &sc->sc_dev, NULL);
156 	}
157 }
158 
159 static void
160 md_attach(parent, self, aux)
161 	struct device	*parent, *self;
162 	void		*aux;
163 {
164 	struct md_softc *sc = (struct md_softc *)self;
165 
166 	bufq_alloc(&sc->sc_buflist, BUFQ_FCFS);
167 
168 	/* XXX - Could accept aux info here to set the config. */
169 #ifdef	MEMORY_DISK_HOOKS
170 	/*
171 	 * This external function might setup a pre-loaded disk.
172 	 * All it would need to do is setup the md_conf struct.
173 	 * See sys/dev/md_root.c for an example.
174 	 */
175 	md_attach_hook(sc->sc_dev.dv_unit, &sc->sc_md);
176 #endif
177 
178 	/*
179 	 * Initialize and attach the disk structure.
180 	 */
181 	sc->sc_dkdev.dk_driver = &mddkdriver;
182 	sc->sc_dkdev.dk_name = sc->sc_dev.dv_xname;
183 	disk_attach(&sc->sc_dkdev);
184 }
185 
186 /*
187  * operational routines:
188  * open, close, read, write, strategy,
189  * ioctl, dump, size
190  */
191 
192 #if MEMORY_DISK_SERVER
193 static int md_server_loop __P((struct md_softc *sc));
194 static int md_ioctl_server __P((struct md_softc *sc,
195 		struct md_conf *umd, struct proc *proc));
196 #endif
197 static int md_ioctl_kalloc __P((struct md_softc *sc,
198 		struct md_conf *umd, struct proc *proc));
199 
200 int
201 mdsize(dev_t dev)
202 {
203 	int unit;
204 	struct md_softc *sc;
205 
206 	unit = MD_UNIT(dev);
207 	if (unit >= ramdisk_ndevs)
208 		return 0;
209 	sc = ramdisk_devs[unit];
210 	if (sc == NULL)
211 		return 0;
212 
213 	if (sc->sc_type == MD_UNCONFIGURED)
214 		return 0;
215 
216 	return (sc->sc_size >> DEV_BSHIFT);
217 }
218 
219 int
220 mdopen(dev, flag, fmt, proc)
221 	dev_t dev;
222 	int flag, fmt;
223 	struct proc *proc;
224 {
225 	int unit;
226 	struct md_softc *sc;
227 
228 	unit = MD_UNIT(dev);
229 	if (unit >= ramdisk_ndevs)
230 		return ENXIO;
231 	sc = ramdisk_devs[unit];
232 	if (sc == NULL)
233 		return ENXIO;
234 
235 	/*
236 	 * The raw partition is used for ioctl to configure.
237 	 */
238 	if (DISKPART(dev) == RAW_PART)
239 		return 0;
240 
241 #ifdef	MEMORY_DISK_HOOKS
242 	/* Call the open hook to allow loading the device. */
243 	md_open_hook(unit, &sc->sc_md);
244 #endif
245 
246 	/*
247 	 * This is a normal, "slave" device, so
248 	 * enforce initialized.
249 	 */
250 	if (sc->sc_type == MD_UNCONFIGURED)
251 		return ENXIO;
252 
253 	return 0;
254 }
255 
256 int
257 mdclose(dev, flag, fmt, proc)
258 	dev_t dev;
259 	int flag, fmt;
260 	struct proc *proc;
261 {
262 	int unit;
263 
264 	unit = MD_UNIT(dev);
265 
266 	if (unit >= ramdisk_ndevs)
267 		return ENXIO;
268 
269 	return 0;
270 }
271 
272 int
273 mdread(dev, uio, flags)
274 	dev_t dev;
275 	struct uio *uio;
276 	int flags;
277 {
278 	int unit;
279 	struct md_softc *sc;
280 
281 	unit = MD_UNIT(dev);
282 
283 	if (unit >= ramdisk_ndevs)
284 		return ENXIO;
285 
286 	sc = ramdisk_devs[unit];
287 
288 	if (sc->sc_type == MD_UNCONFIGURED)
289 		return ENXIO;
290 
291 	return (physio(mdstrategy, NULL, dev, B_READ, minphys, uio));
292 }
293 
294 int
295 mdwrite(dev, uio, flags)
296 	dev_t dev;
297 	struct uio *uio;
298 	int flags;
299 {
300 	int unit;
301 	struct md_softc *sc;
302 
303 	unit = MD_UNIT(dev);
304 
305 	if (unit >= ramdisk_ndevs)
306 		return ENXIO;
307 
308 	sc = ramdisk_devs[unit];
309 
310 	if (sc->sc_type == MD_UNCONFIGURED)
311 		return ENXIO;
312 
313 	return (physio(mdstrategy, NULL, dev, B_WRITE, minphys, uio));
314 }
315 
316 /*
317  * Handle I/O requests, either directly, or
318  * by passing them to the server process.
319  */
320 void
321 mdstrategy(bp)
322 	struct buf *bp;
323 {
324 	int unit;
325 	struct md_softc	*sc;
326 	caddr_t	addr;
327 	size_t off, xfer;
328 
329 	unit = MD_UNIT(bp->b_dev);
330 	sc = ramdisk_devs[unit];
331 
332 	if (sc->sc_type == MD_UNCONFIGURED) {
333 		bp->b_error = ENXIO;
334 		bp->b_flags |= B_ERROR;
335 		goto done;
336 	}
337 
338 	switch (sc->sc_type) {
339 #if MEMORY_DISK_SERVER
340 	case MD_UMEM_SERVER:
341 		/* Just add this job to the server's queue. */
342 		BUFQ_PUT(&sc->sc_buflist, bp);
343 		wakeup((caddr_t)sc);
344 		/* see md_server_loop() */
345 		/* no biodone in this case */
346 		return;
347 #endif	/* MEMORY_DISK_SERVER */
348 
349 	case MD_KMEM_FIXED:
350 	case MD_KMEM_ALLOCATED:
351 		/* These are in kernel space.  Access directly. */
352 		bp->b_resid = bp->b_bcount;
353 		off = (bp->b_blkno << DEV_BSHIFT);
354 		if (off >= sc->sc_size) {
355 			if (bp->b_flags & B_READ)
356 				break;	/* EOF */
357 			goto set_eio;
358 		}
359 		xfer = bp->b_resid;
360 		if (xfer > (sc->sc_size - off))
361 			xfer = (sc->sc_size - off);
362 		addr = sc->sc_addr + off;
363 		if (bp->b_flags & B_READ)
364 			memcpy(bp->b_data, addr, xfer);
365 		else
366 			memcpy(addr, bp->b_data, xfer);
367 		bp->b_resid -= xfer;
368 		break;
369 
370 	default:
371 		bp->b_resid = bp->b_bcount;
372 	set_eio:
373 		bp->b_error = EIO;
374 		bp->b_flags |= B_ERROR;
375 		break;
376 	}
377  done:
378 	biodone(bp);
379 }
380 
381 int
382 mdioctl(dev, cmd, data, flag, proc)
383 	dev_t dev;
384 	u_long cmd;
385 	int flag;
386 	caddr_t data;
387 	struct proc *proc;
388 {
389 	int unit;
390 	struct md_softc *sc;
391 	struct md_conf *umd;
392 
393 	unit = MD_UNIT(dev);
394 	sc = ramdisk_devs[unit];
395 
396 	/* If this is not the raw partition, punt! */
397 	if (DISKPART(dev) != RAW_PART)
398 		return ENOTTY;
399 
400 	umd = (struct md_conf *)data;
401 	switch (cmd) {
402 	case MD_GETCONF:
403 		*umd = sc->sc_md;
404 		return 0;
405 
406 	case MD_SETCONF:
407 		/* Can only set it once. */
408 		if (sc->sc_type != MD_UNCONFIGURED)
409 			break;
410 		switch (umd->md_type) {
411 		case MD_KMEM_ALLOCATED:
412 			return md_ioctl_kalloc(sc, umd, proc);
413 #if MEMORY_DISK_SERVER
414 		case MD_UMEM_SERVER:
415 			return md_ioctl_server(sc, umd, proc);
416 #endif
417 		default:
418 			break;
419 		}
420 		break;
421 	}
422 	return EINVAL;
423 }
424 
425 /*
426  * Handle ioctl MD_SETCONF for (sc_type == MD_KMEM_ALLOCATED)
427  * Just allocate some kernel memory and return.
428  */
429 static int
430 md_ioctl_kalloc(sc, umd, proc)
431 	struct md_softc *sc;
432 	struct md_conf *umd;
433 	struct proc *proc;
434 {
435 	vaddr_t addr;
436 	vsize_t size;
437 
438 	/* Sanity check the size. */
439 	size = umd->md_size;
440 	addr = uvm_km_zalloc(kernel_map, size);
441 	if (!addr)
442 		return ENOMEM;
443 
444 	/* This unit is now configured. */
445 	sc->sc_addr = (caddr_t)addr; 	/* kernel space */
446 	sc->sc_size = (size_t)size;
447 	sc->sc_type = MD_KMEM_ALLOCATED;
448 	return 0;
449 }
450 
451 #if MEMORY_DISK_SERVER
452 
453 /*
454  * Handle ioctl MD_SETCONF for (sc_type == MD_UMEM_SERVER)
455  * Set config, then become the I/O server for this unit.
456  */
457 static int
458 md_ioctl_server(sc, umd, proc)
459 	struct md_softc *sc;
460 	struct md_conf *umd;
461 	struct proc *proc;
462 {
463 	vaddr_t end;
464 	int error;
465 
466 	/* Sanity check addr, size. */
467 	end = (vaddr_t) (umd->md_addr + umd->md_size);
468 
469 	if ((end >= VM_MAXUSER_ADDRESS) ||
470 		(end < ((vaddr_t) umd->md_addr)) )
471 		return EINVAL;
472 
473 	/* This unit is now configured. */
474 	sc->sc_addr = umd->md_addr; 	/* user space */
475 	sc->sc_size = umd->md_size;
476 	sc->sc_type = MD_UMEM_SERVER;
477 
478 	/* Become the server daemon */
479 	error = md_server_loop(sc);
480 
481 	/* This server is now going away! */
482 	sc->sc_type = MD_UNCONFIGURED;
483 	sc->sc_addr = 0;
484 	sc->sc_size = 0;
485 
486 	return (error);
487 }
488 
489 int md_sleep_pri = PWAIT | PCATCH;
490 
491 static int
492 md_server_loop(sc)
493 	struct md_softc *sc;
494 {
495 	struct buf *bp;
496 	caddr_t addr;	/* user space address */
497 	size_t off;	/* offset into "device" */
498 	size_t xfer;	/* amount to transfer */
499 	int error;
500 
501 	for (;;) {
502 		/* Wait for some work to arrive. */
503 		while ((bp = BUFQ_GET(&sc->sc_buflist)) == NULL) {
504 			error = tsleep((caddr_t)sc, md_sleep_pri, "md_idle", 0);
505 			if (error)
506 				return error;
507 		}
508 
509 		/* Do the transfer to/from user space. */
510 		error = 0;
511 		bp->b_resid = bp->b_bcount;
512 		off = (bp->b_blkno << DEV_BSHIFT);
513 		if (off >= sc->sc_size) {
514 			if (bp->b_flags & B_READ)
515 				goto done;	/* EOF (not an error) */
516 			error = EIO;
517 			goto done;
518 		}
519 		xfer = bp->b_resid;
520 		if (xfer > (sc->sc_size - off))
521 			xfer = (sc->sc_size - off);
522 		addr = sc->sc_addr + off;
523 		if (bp->b_flags & B_READ)
524 			error = copyin(addr, bp->b_data, xfer);
525 		else
526 			error = copyout(bp->b_data, addr, xfer);
527 		if (!error)
528 			bp->b_resid -= xfer;
529 
530 	done:
531 		if (error) {
532 			bp->b_error = error;
533 			bp->b_flags |= B_ERROR;
534 		}
535 		biodone(bp);
536 	}
537 }
538 #endif	/* MEMORY_DISK_SERVER */
539