xref: /freebsd/sys/kern/kern_osd.c (revision 859f4d06112d80b010536d79ae886e4649d4f486)
1 /*-
2  * Copyright (c) 2007 Pawel Jakub Dawidek <pjd@FreeBSD.org>
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  */
26 
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
29 
30 #include <sys/param.h>
31 #include <sys/kernel.h>
32 #include <sys/systm.h>
33 #include <sys/sysctl.h>
34 #include <sys/errno.h>
35 #include <sys/jail.h>
36 #include <sys/malloc.h>
37 #include <sys/lock.h>
38 #include <sys/mutex.h>
39 #include <sys/rmlock.h>
40 #include <sys/sx.h>
41 #include <sys/queue.h>
42 #include <sys/proc.h>
43 #include <sys/osd.h>
44 
45 /* OSD (Object Specific Data) */
46 
47 /*
48  * Lock key:
49  *  (m) osd_module_lock
50  *  (o) osd_object_lock
51  *  (l) osd_list_lock
52  */
53 struct osd_master {
54 	struct sx		 osd_module_lock;
55 	struct rmlock		 osd_object_lock;
56 	struct mtx		 osd_list_lock;
57 	LIST_HEAD(, osd)	 osd_list;		/* (m) */
58 	osd_destructor_t	*osd_destructors;	/* (o) */
59 	osd_method_t		*osd_methods;		/* (m) */
60 	u_int			 osd_ntslots;		/* (m) */
61 	const u_int		 osd_nmethods;
62 };
63 
64 static MALLOC_DEFINE(M_OSD, "osd", "Object Specific Data");
65 
66 static int osd_debug = 0;
67 SYSCTL_INT(_debug, OID_AUTO, osd, CTLFLAG_RWTUN, &osd_debug, 0, "OSD debug level");
68 
69 #define	OSD_DEBUG(...)	do {						\
70 	if (osd_debug) {						\
71 		printf("OSD (%s:%u): ", __func__, __LINE__);		\
72 		printf(__VA_ARGS__);					\
73 		printf("\n");						\
74 	}								\
75 } while (0)
76 
77 static void do_osd_del(u_int type, struct osd *osd, u_int slot,
78     int list_locked);
79 
80 /*
81  * List of objects with OSD.
82  */
83 struct osd_master osdm[OSD_LAST + 1] = {
84 	[OSD_JAIL] = { .osd_nmethods = PR_MAXMETHOD },
85 };
86 
87 static void
88 osd_default_destructor(void *value __unused)
89 {
90 	/* Do nothing. */
91 }
92 
93 int
94 osd_register(u_int type, osd_destructor_t destructor, osd_method_t *methods)
95 {
96 	void *newptr;
97 	u_int i, m;
98 
99 	KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type."));
100 
101 	/*
102 	 * If no destructor is given, use default one. We need to use some
103 	 * destructor, because NULL destructor means unused slot.
104 	 */
105 	if (destructor == NULL)
106 		destructor = osd_default_destructor;
107 
108 	sx_xlock(&osdm[type].osd_module_lock);
109 	/*
110 	 * First, we try to find unused slot.
111 	 */
112 	for (i = 0; i < osdm[type].osd_ntslots; i++) {
113 		if (osdm[type].osd_destructors[i] == NULL) {
114 			OSD_DEBUG("Unused slot found (type=%u, slot=%u).",
115 			    type, i);
116 			break;
117 		}
118 	}
119 	/*
120 	 * If no unused slot was found, allocate one.
121 	 */
122 	if (i == osdm[type].osd_ntslots) {
123 		osdm[type].osd_ntslots++;
124 		if (osdm[type].osd_nmethods != 0)
125 			osdm[type].osd_methods = realloc(osdm[type].osd_methods,
126 			    sizeof(osd_method_t) * osdm[type].osd_ntslots *
127 			    osdm[type].osd_nmethods, M_OSD, M_WAITOK);
128 		newptr = malloc(sizeof(osd_destructor_t) *
129 		    osdm[type].osd_ntslots, M_OSD, M_WAITOK);
130 		rm_wlock(&osdm[type].osd_object_lock);
131 		bcopy(osdm[type].osd_destructors, newptr,
132 		    sizeof(osd_destructor_t) * i);
133 		free(osdm[type].osd_destructors, M_OSD);
134 		osdm[type].osd_destructors = newptr;
135 		rm_wunlock(&osdm[type].osd_object_lock);
136 		OSD_DEBUG("New slot allocated (type=%u, slot=%u).",
137 		    type, i + 1);
138 	}
139 
140 	osdm[type].osd_destructors[i] = destructor;
141 	if (osdm[type].osd_nmethods != 0) {
142 		for (m = 0; m < osdm[type].osd_nmethods; m++)
143 			osdm[type].osd_methods[i * osdm[type].osd_nmethods + m]
144 			    = methods != NULL ? methods[m] : NULL;
145 	}
146 	sx_xunlock(&osdm[type].osd_module_lock);
147 	return (i + 1);
148 }
149 
150 void
151 osd_deregister(u_int type, u_int slot)
152 {
153 	struct osd *osd, *tosd;
154 
155 	KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type."));
156 	KASSERT(slot > 0, ("Invalid slot."));
157 	KASSERT(osdm[type].osd_destructors[slot - 1] != NULL, ("Unused slot."));
158 
159 	sx_xlock(&osdm[type].osd_module_lock);
160 	rm_wlock(&osdm[type].osd_object_lock);
161 	/*
162 	 * Free all OSD for the given slot.
163 	 */
164 	mtx_lock(&osdm[type].osd_list_lock);
165 	LIST_FOREACH_SAFE(osd, &osdm[type].osd_list, osd_next, tosd)
166 		do_osd_del(type, osd, slot, 1);
167 	mtx_unlock(&osdm[type].osd_list_lock);
168 	/*
169 	 * Set destructor to NULL to free the slot.
170 	 */
171 	osdm[type].osd_destructors[slot - 1] = NULL;
172 	if (slot == osdm[type].osd_ntslots) {
173 		osdm[type].osd_ntslots--;
174 		osdm[type].osd_destructors = realloc(osdm[type].osd_destructors,
175 		    sizeof(osd_destructor_t) * osdm[type].osd_ntslots, M_OSD,
176 		    M_NOWAIT | M_ZERO);
177 		if (osdm[type].osd_nmethods != 0)
178 			osdm[type].osd_methods = realloc(osdm[type].osd_methods,
179 			    sizeof(osd_method_t) * osdm[type].osd_ntslots *
180 			    osdm[type].osd_nmethods, M_OSD, M_NOWAIT | M_ZERO);
181 		/*
182 		 * We always reallocate to smaller size, so we assume it will
183 		 * always succeed.
184 		 */
185 		KASSERT(osdm[type].osd_destructors != NULL &&
186 		    (osdm[type].osd_nmethods == 0 ||
187 		     osdm[type].osd_methods != NULL), ("realloc() failed"));
188 		OSD_DEBUG("Deregistration of the last slot (type=%u, slot=%u).",
189 		    type, slot);
190 	} else {
191 		OSD_DEBUG("Slot deregistration (type=%u, slot=%u).",
192 		    type, slot);
193 	}
194 	rm_wunlock(&osdm[type].osd_object_lock);
195 	sx_xunlock(&osdm[type].osd_module_lock);
196 }
197 
198 int
199 osd_set(u_int type, struct osd *osd, u_int slot, void *value)
200 {
201 	struct rm_priotracker tracker;
202 
203 	KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type."));
204 	KASSERT(slot > 0, ("Invalid slot."));
205 	KASSERT(osdm[type].osd_destructors[slot - 1] != NULL, ("Unused slot."));
206 
207 	rm_rlock(&osdm[type].osd_object_lock, &tracker);
208 	if (slot > osd->osd_nslots) {
209 		if (value == NULL) {
210 			OSD_DEBUG(
211 			    "Not allocating null slot (type=%u, slot=%u).",
212 			    type, slot);
213 			rm_runlock(&osdm[type].osd_object_lock, &tracker);
214 			return (0);
215 		} else if (osd->osd_nslots == 0) {
216 			/*
217 			 * First OSD for this object, so we need to allocate
218 			 * space and put it onto the list.
219 			 */
220 			osd->osd_slots = malloc(sizeof(void *) * slot, M_OSD,
221 			    M_NOWAIT | M_ZERO);
222 			if (osd->osd_slots == NULL) {
223 				rm_runlock(&osdm[type].osd_object_lock,
224 				    &tracker);
225 				return (ENOMEM);
226 			}
227 			osd->osd_nslots = slot;
228 			mtx_lock(&osdm[type].osd_list_lock);
229 			LIST_INSERT_HEAD(&osdm[type].osd_list, osd, osd_next);
230 			mtx_unlock(&osdm[type].osd_list_lock);
231 			OSD_DEBUG("Setting first slot (type=%u).", type);
232 		} else {
233 			void *newptr;
234 
235 			/*
236 			 * Too few slots allocated here, needs to extend
237 			 * the array.
238 			 */
239 			newptr = realloc(osd->osd_slots, sizeof(void *) * slot,
240 			    M_OSD, M_NOWAIT | M_ZERO);
241 			if (newptr == NULL) {
242 				rm_runlock(&osdm[type].osd_object_lock,
243 				    &tracker);
244 				return (ENOMEM);
245 			}
246 			osd->osd_slots = newptr;
247 			osd->osd_nslots = slot;
248 			OSD_DEBUG("Growing slots array (type=%u).", type);
249 		}
250 	}
251 	OSD_DEBUG("Setting slot value (type=%u, slot=%u, value=%p).", type,
252 	    slot, value);
253 	osd->osd_slots[slot - 1] = value;
254 	rm_runlock(&osdm[type].osd_object_lock, &tracker);
255 	return (0);
256 }
257 
258 void *
259 osd_get(u_int type, struct osd *osd, u_int slot)
260 {
261 	struct rm_priotracker tracker;
262 	void *value;
263 
264 	KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type."));
265 	KASSERT(slot > 0, ("Invalid slot."));
266 	KASSERT(osdm[type].osd_destructors[slot - 1] != NULL, ("Unused slot."));
267 
268 	rm_rlock(&osdm[type].osd_object_lock, &tracker);
269 	if (slot > osd->osd_nslots) {
270 		value = NULL;
271 		OSD_DEBUG("Slot doesn't exist (type=%u, slot=%u).", type, slot);
272 	} else {
273 		value = osd->osd_slots[slot - 1];
274 		OSD_DEBUG("Returning slot value (type=%u, slot=%u, value=%p).",
275 		    type, slot, value);
276 	}
277 	rm_runlock(&osdm[type].osd_object_lock, &tracker);
278 	return (value);
279 }
280 
281 void
282 osd_del(u_int type, struct osd *osd, u_int slot)
283 {
284 	struct rm_priotracker tracker;
285 
286 	rm_rlock(&osdm[type].osd_object_lock, &tracker);
287 	do_osd_del(type, osd, slot, 0);
288 	rm_runlock(&osdm[type].osd_object_lock, &tracker);
289 }
290 
291 static void
292 do_osd_del(u_int type, struct osd *osd, u_int slot, int list_locked)
293 {
294 	int i;
295 
296 	KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type."));
297 	KASSERT(slot > 0, ("Invalid slot."));
298 	KASSERT(osdm[type].osd_destructors[slot - 1] != NULL, ("Unused slot."));
299 
300 	OSD_DEBUG("Deleting slot (type=%u, slot=%u).", type, slot);
301 
302 	if (slot > osd->osd_nslots) {
303 		OSD_DEBUG("Slot doesn't exist (type=%u, slot=%u).", type, slot);
304 		return;
305 	}
306 	if (osd->osd_slots[slot - 1] != NULL) {
307 		osdm[type].osd_destructors[slot - 1](osd->osd_slots[slot - 1]);
308 		osd->osd_slots[slot - 1] = NULL;
309 	}
310 	for (i = osd->osd_nslots - 1; i >= 0; i--) {
311 		if (osd->osd_slots[i] != NULL) {
312 			OSD_DEBUG("Slot still has a value (type=%u, slot=%u).",
313 			    type, i + 1);
314 			break;
315 		}
316 	}
317 	if (i == -1) {
318 		/* No values left for this object. */
319 		OSD_DEBUG("No more slots left (type=%u).", type);
320 		if (!list_locked)
321 			mtx_lock(&osdm[type].osd_list_lock);
322 		LIST_REMOVE(osd, osd_next);
323 		if (!list_locked)
324 			mtx_unlock(&osdm[type].osd_list_lock);
325 		free(osd->osd_slots, M_OSD);
326 		osd->osd_slots = NULL;
327 		osd->osd_nslots = 0;
328 	} else if (slot == osd->osd_nslots) {
329 		/* This was the last slot. */
330 		osd->osd_slots = realloc(osd->osd_slots,
331 		    sizeof(void *) * (i + 1), M_OSD, M_NOWAIT | M_ZERO);
332 		/*
333 		 * We always reallocate to smaller size, so we assume it will
334 		 * always succeed.
335 		 */
336 		KASSERT(osd->osd_slots != NULL, ("realloc() failed"));
337 		osd->osd_nslots = i + 1;
338 		OSD_DEBUG("Reducing slots array to %u (type=%u).",
339 		    osd->osd_nslots, type);
340 	}
341 }
342 
343 int
344 osd_call(u_int type, u_int method, void *obj, void *data)
345 {
346 	osd_method_t methodfun;
347 	int error, i;
348 
349 	KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type."));
350 	KASSERT(method < osdm[type].osd_nmethods, ("Invalid method."));
351 
352 	/*
353 	 * Call this method for every slot that defines it, stopping if an
354 	 * error is encountered.
355 	 */
356 	error = 0;
357 	sx_slock(&osdm[type].osd_module_lock);
358 	for (i = 0; i < osdm[type].osd_ntslots; i++) {
359 		methodfun = osdm[type].osd_methods[i * osdm[type].osd_nmethods +
360 		    method];
361 		if (methodfun != NULL && (error = methodfun(obj, data)) != 0)
362 			break;
363 	}
364 	sx_sunlock(&osdm[type].osd_module_lock);
365 	return (error);
366 }
367 
368 void
369 osd_exit(u_int type, struct osd *osd)
370 {
371 	struct rm_priotracker tracker;
372 	u_int i;
373 
374 	KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type."));
375 
376 	if (osd->osd_nslots == 0) {
377 		KASSERT(osd->osd_slots == NULL, ("Non-null osd_slots."));
378 		/* No OSD attached, just leave. */
379 		return;
380 	}
381 
382 	rm_rlock(&osdm[type].osd_object_lock, &tracker);
383 	for (i = 1; i <= osd->osd_nslots; i++) {
384 		if (osdm[type].osd_destructors[i - 1] != NULL)
385 			do_osd_del(type, osd, i, 0);
386 		else
387 			OSD_DEBUG("Unused slot (type=%u, slot=%u).", type, i);
388 	}
389 	rm_runlock(&osdm[type].osd_object_lock, &tracker);
390 	OSD_DEBUG("Object exit (type=%u).", type);
391 }
392 
393 static void
394 osd_init(void *arg __unused)
395 {
396 	u_int i;
397 
398 	for (i = OSD_FIRST; i <= OSD_LAST; i++) {
399 		sx_init(&osdm[i].osd_module_lock, "osd_module");
400 		rm_init(&osdm[i].osd_object_lock, "osd_object");
401 		mtx_init(&osdm[i].osd_list_lock, "osd_list", NULL, MTX_DEF);
402 		LIST_INIT(&osdm[i].osd_list);
403 		osdm[i].osd_destructors = NULL;
404 		osdm[i].osd_ntslots = 0;
405 		osdm[i].osd_methods = NULL;
406 	}
407 }
408 SYSINIT(osd, SI_SUB_LOCK, SI_ORDER_ANY, osd_init, NULL);
409