xref: /dragonfly/sys/dev/disk/md/md.c (revision f746689a) 
1 /*
2  * ----------------------------------------------------------------------------
3  * "THE BEER-WARE LICENSE" (Revision 42):
4  * <phk@FreeBSD.ORG> wrote this file.  As long as you retain this notice you
5  * can do whatever you want with this stuff. If we meet some day, and you think
6  * this stuff is worth it, you can buy me a beer in return.   Poul-Henning Kamp
7  * ----------------------------------------------------------------------------
8  *
9  * $FreeBSD: src/sys/dev/md/md.c,v 1.8.2.2 2002/08/19 17:43:34 jdp Exp $
10  * $DragonFly: src/sys/dev/disk/md/md.c,v 1.20 2008/09/07 08:09:39 swildner Exp $
11  *
12  */
13 
14 #include "opt_md.h"		/* We have adopted some tasks from MFS */
15 
16 #include <sys/param.h>
17 #include <sys/systm.h>
18 #include <sys/buf.h>
19 #include <sys/conf.h>
20 #include <sys/devicestat.h>
21 #include <sys/disk.h>
22 #include <sys/kernel.h>
23 #include <sys/malloc.h>
24 #include <sys/sysctl.h>
25 #include <sys/linker.h>
26 #include <sys/proc.h>
27 #include <sys/buf2.h>
28 #include <sys/thread2.h>
29 
30 #ifndef MD_NSECT
31 #define MD_NSECT (10000 * 2)
32 #endif
33 
34 MALLOC_DEFINE(M_MD, "MD disk", "Memory Disk");
35 MALLOC_DEFINE(M_MDSECT, "MD sectors", "Memory Disk Sectors");
36 
37 static int md_debug;
38 SYSCTL_INT(_debug, OID_AUTO, mddebug, CTLFLAG_RW, &md_debug, 0, "");
39 
40 #if defined(MD_ROOT) && defined(MD_ROOT_SIZE)
41 /* Image gets put here: */
42 static u_char mfs_root[MD_ROOT_SIZE*1024] = "MFS Filesystem goes here";
43 static u_char end_mfs_root[] __unused = "MFS Filesystem had better STOP here";
44 #endif
45 
46 static int mdrootready;
47 
48 static void mdcreate_malloc(void);
49 
50 #define CDEV_MAJOR	95
51 
52 static d_strategy_t mdstrategy;
53 static d_strategy_t mdstrategy_preload;
54 static d_strategy_t mdstrategy_malloc;
55 static d_open_t mdopen;
56 static d_ioctl_t mdioctl;
57 
58 static struct dev_ops md_ops = {
59 	{ "md", CDEV_MAJOR, D_DISK | D_CANFREE | D_MEMDISK },
60         .d_open =	mdopen,
61         .d_close =	nullclose,
62         .d_read =	physread,
63         .d_write =	physwrite,
64         .d_ioctl =	mdioctl,
65         .d_strategy =	mdstrategy,
66 };
67 
68 struct md_s {
69 	int unit;
70 	struct devstat stats;
71 	struct bio_queue_head bio_queue;
72 	struct disk disk;
73 	cdev_t dev;
74 	int busy;
75 	enum {MD_MALLOC, MD_PRELOAD} type;
76 	unsigned nsect;
77 
78 	/* MD_MALLOC related fields */
79 	unsigned nsecp;
80 	u_char **secp;
81 
82 	/* MD_PRELOAD related fields */
83 	u_char *pl_ptr;
84 	unsigned pl_len;
85 };
86 
87 static int mdunits;
88 
89 static int
90 mdopen(struct dev_open_args *ap)
91 {
92 	cdev_t dev = ap->a_head.a_dev;
93 	struct md_s *sc;
94 	struct disk_info info;
95 
96 	if (md_debug)
97 		kprintf("mdopen(%s %x %x)\n",
98 			devtoname(dev), ap->a_oflags, ap->a_devtype);
99 
100 	sc = dev->si_drv1;
101 	if (sc->unit + 1 == mdunits)
102 		mdcreate_malloc();
103 
104 	bzero(&info, sizeof(info));
105 	info.d_media_blksize = DEV_BSIZE;	/* mandatory */
106 	info.d_media_blocks = sc->nsect;
107 
108 	info.d_secpertrack = 1024;		/* optional */
109 	info.d_nheads = 1;
110 	info.d_secpercyl = info.d_secpertrack * info.d_nheads;
111 	info.d_ncylinders = (u_int)(info.d_media_blocks / info.d_secpercyl);
112 	disk_setdiskinfo(&sc->disk, &info);
113 
114 	return (0);
115 }
116 
117 static int
118 mdioctl(struct dev_ioctl_args *ap)
119 {
120 	cdev_t dev = ap->a_head.a_dev;
121 
122 	if (md_debug)
123 		kprintf("mdioctl(%s %lx %p %x)\n",
124 			devtoname(dev), ap->a_cmd, ap->a_data, ap->a_fflag);
125 
126 	return (ENOIOCTL);
127 }
128 
129 static int
130 mdstrategy(struct dev_strategy_args *ap)
131 {
132 	cdev_t dev = ap->a_head.a_dev;
133 	struct bio *bio = ap->a_bio;
134 	struct buf *bp = bio->bio_buf;
135 	struct md_s *sc;
136 
137 	if (md_debug > 1) {
138 		kprintf("mdstrategy(%p) %s %08x, %lld, %d, %p)\n",
139 		    bp, devtoname(dev), bp->b_flags, bio->bio_offset,
140 		    bp->b_bcount, bp->b_data);
141 	}
142 	bio->bio_driver_info = dev;
143 	sc = dev->si_drv1;
144 	if (sc->type == MD_MALLOC) {
145 		mdstrategy_malloc(ap);
146 	} else {
147 		mdstrategy_preload(ap);
148 	}
149 	return(0);
150 }
151 
152 
153 static int
154 mdstrategy_malloc(struct dev_strategy_args *ap)
155 {
156 	cdev_t dev = ap->a_head.a_dev;
157 	struct bio *bio = ap->a_bio;
158 	struct buf *bp = bio->bio_buf;
159 	unsigned secno, nsec, secval, uc;
160 	u_char *secp, **secpp, *dst;
161 	struct md_s *sc;
162 	int i;
163 
164 	if (md_debug > 1)
165 		kprintf("mdstrategy_malloc(%p) %s %08xx, %lld, %d, %p)\n",
166 		    bp, devtoname(dev), bp->b_flags, bio->bio_offset,
167 		    bp->b_bcount, bp->b_data);
168 
169 	sc = dev->si_drv1;
170 
171 	crit_enter();
172 
173 	bioqdisksort(&sc->bio_queue, bio);
174 
175 	if (sc->busy) {
176 		crit_exit();
177 		return(0);
178 	}
179 
180 	sc->busy++;
181 
182 	while (1) {
183 		bio = bioq_first(&sc->bio_queue);
184 		if (bio == NULL) {
185 			crit_exit();
186 			break;
187 		}
188 		crit_exit();
189 		bioq_remove(&sc->bio_queue, bio);
190 		bp = bio->bio_buf;
191 
192 		devstat_start_transaction(&sc->stats);
193 
194 		switch (bp->b_cmd) {
195 		case BUF_CMD_FREEBLKS:
196 		case BUF_CMD_READ:
197 		case BUF_CMD_WRITE:
198 			break;
199 		default:
200 			panic("md: bad b_cmd %d", bp->b_cmd);
201 		}
202 
203 		nsec = bp->b_bcount >> DEV_BSHIFT;
204 		secno = (unsigned)(bio->bio_offset >> DEV_BSHIFT);
205 		dst = bp->b_data;
206 		while (nsec--) {
207 			if (secno < sc->nsecp) {
208 				secpp = &sc->secp[secno];
209 				if ((u_int)*secpp > 255) {
210 					secp = *secpp;
211 					secval = 0;
212 				} else {
213 					secp = 0;
214 					secval = (u_int) *secpp;
215 				}
216 			} else {
217 				secpp = 0;
218 				secp = 0;
219 				secval = 0;
220 			}
221 			if (md_debug > 2)
222 				kprintf("%08x %p %p %d\n", bp->b_flags, secpp, secp, secval);
223 
224 			switch (bp->b_cmd) {
225 			case BUF_CMD_FREEBLKS:
226 				if (secpp) {
227 					if (secp)
228 						FREE(secp, M_MDSECT);
229 					*secpp = 0;
230 				}
231 				break;
232 			case BUF_CMD_READ:
233 				if (secp) {
234 					bcopy(secp, dst, DEV_BSIZE);
235 				} else if (secval) {
236 					for (i = 0; i < DEV_BSIZE; i++)
237 						dst[i] = secval;
238 				} else {
239 					bzero(dst, DEV_BSIZE);
240 				}
241 				break;
242 			case BUF_CMD_WRITE:
243 				uc = dst[0];
244 				for (i = 1; i < DEV_BSIZE; i++)
245 					if (dst[i] != uc)
246 						break;
247 				if (i == DEV_BSIZE && !uc) {
248 					if (secp)
249 						FREE(secp, M_MDSECT);
250 					if (secpp)
251 						*secpp = (u_char *)uc;
252 				} else {
253 					if (!secpp) {
254 						MALLOC(secpp, u_char **, (secno + nsec + 1) * sizeof(u_char *), M_MD, M_WAITOK | M_ZERO);
255 						bcopy(sc->secp, secpp, sc->nsecp * sizeof(u_char *));
256 						FREE(sc->secp, M_MD);
257 						sc->secp = secpp;
258 						sc->nsecp = secno + nsec + 1;
259 						secpp = &sc->secp[secno];
260 					}
261 					if (i == DEV_BSIZE) {
262 						if (secp)
263 							FREE(secp, M_MDSECT);
264 						*secpp = (u_char *)uc;
265 					} else {
266 						if (!secp)
267 							MALLOC(secp, u_char *, DEV_BSIZE, M_MDSECT, M_WAITOK);
268 						bcopy(dst, secp, DEV_BSIZE);
269 
270 						*secpp = secp;
271 					}
272 				}
273 				break;
274 			default:
275 				panic("md: bad b_cmd %d", bp->b_cmd);
276 
277 			}
278 			secno++;
279 			dst += DEV_BSIZE;
280 		}
281 		bp->b_resid = 0;
282 		devstat_end_transaction_buf(&sc->stats, bp);
283 		biodone(bio);
284 		crit_enter();
285 	}
286 	sc->busy = 0;
287 	return(0);
288 }
289 
290 
291 static int
292 mdstrategy_preload(struct dev_strategy_args *ap)
293 {
294 	cdev_t dev = ap->a_head.a_dev;
295 	struct bio *bio = ap->a_bio;
296 	struct buf *bp = bio->bio_buf;
297 	struct md_s *sc;
298 
299 	if (md_debug > 1)
300 		kprintf("mdstrategy_preload(%p) %s %08x, %lld, %d, %p)\n",
301 		    bp, devtoname(dev), bp->b_flags, bio->bio_offset,
302 		    bp->b_bcount, bp->b_data);
303 
304 	sc = dev->si_drv1;
305 
306 	crit_enter();
307 
308 	bioqdisksort(&sc->bio_queue, bio);
309 
310 	if (sc->busy) {
311 		crit_exit();
312 		return(0);
313 	}
314 
315 	sc->busy++;
316 
317 	while (1) {
318 		bio = bioq_first(&sc->bio_queue);
319 		if (bio)
320 			bioq_remove(&sc->bio_queue, bio);
321 		crit_exit();
322 		if (bio == NULL)
323 			break;
324 
325 		devstat_start_transaction(&sc->stats);
326 
327 		switch (bp->b_cmd) {
328 		case BUF_CMD_FREEBLKS:
329 			break;
330 		case BUF_CMD_READ:
331 			bcopy(sc->pl_ptr + bio->bio_offset,
332 			       bp->b_data, bp->b_bcount);
333 			break;
334 		case BUF_CMD_WRITE:
335 			bcopy(bp->b_data, sc->pl_ptr + bio->bio_offset,
336 			      bp->b_bcount);
337 			break;
338 		default:
339 			panic("md: bad cmd %d\n", bp->b_cmd);
340 		}
341 		bp->b_resid = 0;
342 		devstat_end_transaction_buf(&sc->stats, bp);
343 		biodone(bio);
344 		crit_enter();
345 	}
346 	sc->busy = 0;
347 	return(0);
348 }
349 
350 static struct md_s *
351 mdcreate(void)
352 {
353 	struct md_s *sc;
354 
355 	MALLOC(sc, struct md_s *,sizeof(*sc), M_MD, M_WAITOK | M_ZERO);
356 	sc->unit = mdunits++;
357 	bioq_init(&sc->bio_queue);
358 	devstat_add_entry(&sc->stats, "md", sc->unit, DEV_BSIZE,
359 		DEVSTAT_NO_ORDERED_TAGS,
360 		DEVSTAT_TYPE_DIRECT | DEVSTAT_TYPE_IF_OTHER,
361 		DEVSTAT_PRIORITY_OTHER);
362 	sc->dev = disk_create(sc->unit, &sc->disk, &md_ops);
363 	sc->dev->si_drv1 = sc;
364 	sc->dev->si_iosize_max = DFLTPHYS;
365 
366 	return (sc);
367 }
368 
369 static void
370 mdcreate_preload(u_char *image, unsigned length)
371 {
372 	struct md_s *sc;
373 
374 	sc = mdcreate();
375 	sc->type = MD_PRELOAD;
376 	sc->nsect = length / DEV_BSIZE;
377 	sc->pl_ptr = image;
378 	sc->pl_len = length;
379 
380 	if (sc->unit == 0)
381 		mdrootready = 1;
382 }
383 
384 static void
385 mdcreate_malloc(void)
386 {
387 	struct md_s *sc;
388 
389 	sc = mdcreate();
390 	sc->type = MD_MALLOC;
391 
392 	sc->nsect = MD_NSECT;	/* for now */
393 	MALLOC(sc->secp, u_char **, sizeof(u_char *), M_MD, M_WAITOK | M_ZERO);
394 	sc->nsecp = 1;
395 	kprintf("md%d: Malloc disk\n", sc->unit);
396 }
397 
398 static void
399 md_drvinit(void *unused)
400 {
401 
402 	caddr_t mod;
403 	caddr_t c;
404 	u_char *ptr, *name, *type;
405 	unsigned len;
406 
407 #ifdef MD_ROOT_SIZE
408 	mdcreate_preload(mfs_root, MD_ROOT_SIZE*1024);
409 #endif
410 	mod = NULL;
411 	while ((mod = preload_search_next_name(mod)) != NULL) {
412 		name = (char *)preload_search_info(mod, MODINFO_NAME);
413 		type = (char *)preload_search_info(mod, MODINFO_TYPE);
414 		if (name == NULL)
415 			continue;
416 		if (type == NULL)
417 			continue;
418 		if (strcmp(type, "md_image") && strcmp(type, "mfs_root"))
419 			continue;
420 		c = preload_search_info(mod, MODINFO_ADDR);
421 		ptr = *(u_char **)c;
422 		c = preload_search_info(mod, MODINFO_SIZE);
423 		len = *(unsigned *)c;
424 		kprintf("md%d: Preloaded image <%s> %d bytes at %p\n",
425 		   mdunits, name, len, ptr);
426 		mdcreate_preload(ptr, len);
427 	}
428 	mdcreate_malloc();
429 }
430 
431 SYSINIT(mddev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR, md_drvinit,NULL)
432 
433 #ifdef MD_ROOT
434 static void
435 md_takeroot(void *junk)
436 {
437 	if (mdrootready)
438 		rootdevnames[0] = "ufs:/dev/md0c";
439 }
440 
441 SYSINIT(md_root, SI_SUB_MOUNT_ROOT, SI_ORDER_FIRST, md_takeroot, NULL);
442 #endif
443