1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2007 Pawel Jakub Dawidek <pjd@FreeBSD.org>
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 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <sys/param.h>
30 #include <sys/kernel.h>
31 #include <sys/systm.h>
32 #include <sys/sysctl.h>
33 #include <sys/errno.h>
34 #include <sys/jail.h>
35 #include <sys/malloc.h>
36 #include <sys/lock.h>
37 #include <sys/mutex.h>
38 #include <sys/rmlock.h>
39 #include <sys/sx.h>
40 #include <sys/queue.h>
41 #include <sys/proc.h>
42 #include <sys/osd.h>
43
44 /* OSD (Object Specific Data) */
45
46 /*
47 * Lock key:
48 * (m) osd_module_lock
49 * (o) osd_object_lock
50 * (l) osd_list_lock
51 */
52 struct osd_master {
53 struct sx osd_module_lock;
54 struct rmlock osd_object_lock;
55 struct mtx osd_list_lock;
56 LIST_HEAD(, osd) osd_list; /* (l) */
57 osd_destructor_t *osd_destructors; /* (o) */
58 osd_method_t *osd_methods; /* (m) */
59 u_int osd_ntslots; /* (m) */
60 const u_int osd_nmethods;
61 };
62
63 static MALLOC_DEFINE(M_OSD, "osd", "Object Specific Data");
64
65 static int osd_debug = 0;
66 SYSCTL_INT(_debug, OID_AUTO, osd, CTLFLAG_RWTUN, &osd_debug, 0, "OSD debug level");
67
68 #define OSD_DEBUG(...) do { \
69 if (osd_debug) { \
70 printf("OSD (%s:%u): ", __func__, __LINE__); \
71 printf(__VA_ARGS__); \
72 printf("\n"); \
73 } \
74 } while (0)
75
76 static void do_osd_del(u_int type, struct osd *osd, u_int slot,
77 int list_locked);
78
79 /*
80 * List of objects with OSD.
81 */
82 struct osd_master osdm[OSD_LAST + 1] = {
83 [OSD_JAIL] = { .osd_nmethods = PR_MAXMETHOD },
84 };
85
86 static void
osd_default_destructor(void * value __unused)87 osd_default_destructor(void *value __unused)
88 {
89 /* Do nothing. */
90 }
91
92 int
osd_register(u_int type,osd_destructor_t destructor,osd_method_t * methods)93 osd_register(u_int type, osd_destructor_t destructor, osd_method_t *methods)
94 {
95 void *newptr;
96 u_int i, m;
97
98 KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type."));
99
100 /*
101 * If no destructor is given, use default one. We need to use some
102 * destructor, because NULL destructor means unused slot.
103 */
104 if (destructor == NULL)
105 destructor = osd_default_destructor;
106
107 sx_xlock(&osdm[type].osd_module_lock);
108 /*
109 * First, we try to find unused slot.
110 */
111 for (i = 0; i < osdm[type].osd_ntslots; i++) {
112 if (osdm[type].osd_destructors[i] == NULL) {
113 OSD_DEBUG("Unused slot found (type=%u, slot=%u).",
114 type, i + 1);
115 break;
116 }
117 }
118 /*
119 * If no unused slot was found, allocate one.
120 */
121 if (i == osdm[type].osd_ntslots) {
122 osdm[type].osd_ntslots++;
123 if (osdm[type].osd_nmethods != 0)
124 osdm[type].osd_methods = realloc(osdm[type].osd_methods,
125 sizeof(osd_method_t) * osdm[type].osd_ntslots *
126 osdm[type].osd_nmethods, M_OSD, M_WAITOK);
127 newptr = malloc(sizeof(osd_destructor_t) *
128 osdm[type].osd_ntslots, M_OSD, M_WAITOK);
129 rm_wlock(&osdm[type].osd_object_lock);
130 bcopy(osdm[type].osd_destructors, newptr,
131 sizeof(osd_destructor_t) * i);
132 free(osdm[type].osd_destructors, M_OSD);
133 osdm[type].osd_destructors = newptr;
134 rm_wunlock(&osdm[type].osd_object_lock);
135 OSD_DEBUG("New slot allocated (type=%u, slot=%u).",
136 type, i + 1);
137 }
138
139 osdm[type].osd_destructors[i] = destructor;
140 if (osdm[type].osd_nmethods != 0) {
141 for (m = 0; m < osdm[type].osd_nmethods; m++)
142 osdm[type].osd_methods[i * osdm[type].osd_nmethods + m]
143 = methods != NULL ? methods[m] : NULL;
144 }
145 sx_xunlock(&osdm[type].osd_module_lock);
146 return (i + 1);
147 }
148
149 void
osd_deregister(u_int type,u_int slot)150 osd_deregister(u_int type, u_int slot)
151 {
152 struct osd *osd, *tosd;
153
154 KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type."));
155 KASSERT(slot > 0, ("Invalid slot."));
156
157 sx_xlock(&osdm[type].osd_module_lock);
158 rm_wlock(&osdm[type].osd_object_lock);
159 KASSERT(osdm[type].osd_destructors[slot - 1] != NULL, ("Unused slot."));
160
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 /*
170 * Set destructor to NULL to free the slot. We don't bother actually
171 * freeing any memory here because we'll gracefully reuse any freed
172 * slots, and reallocating the arrays as a smaller chunk of memory isn't
173 * actually guaranteed to succeed. As such, we'll err on the side of
174 * caution and just leave it be since these are generally modestly sized
175 * allocations.
176 */
177 osdm[type].osd_destructors[slot - 1] = NULL;
178 OSD_DEBUG("Slot deregistration (type=%u, slot=%u).", type, slot);
179
180 rm_wunlock(&osdm[type].osd_object_lock);
181 sx_xunlock(&osdm[type].osd_module_lock);
182 }
183
184 int
osd_set(u_int type,struct osd * osd,u_int slot,void * value)185 osd_set(u_int type, struct osd *osd, u_int slot, void *value)
186 {
187
188 return (osd_set_reserved(type, osd, slot, NULL, value));
189 }
190
191 void **
osd_reserve(u_int slot)192 osd_reserve(u_int slot)
193 {
194
195 KASSERT(slot > 0, ("Invalid slot."));
196
197 OSD_DEBUG("Reserving slot array (slot=%u).", slot);
198 return (malloc(sizeof(void *) * slot, M_OSD, M_WAITOK | M_ZERO));
199 }
200
201 int
osd_set_reserved(u_int type,struct osd * osd,u_int slot,void ** rsv,void * value)202 osd_set_reserved(u_int type, struct osd *osd, u_int slot, void **rsv,
203 void *value)
204 {
205 struct rm_priotracker tracker;
206
207 KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type."));
208 KASSERT(slot > 0, ("Invalid slot."));
209
210 rm_rlock(&osdm[type].osd_object_lock, &tracker);
211 KASSERT(osdm[type].osd_destructors[slot - 1] != NULL, ("Unused slot."));
212
213 if (slot > osd->osd_nslots) {
214 void **newptr;
215
216 if (value == NULL) {
217 OSD_DEBUG(
218 "Not allocating null slot (type=%u, slot=%u).",
219 type, slot);
220 rm_runlock(&osdm[type].osd_object_lock, &tracker);
221 if (rsv)
222 osd_free_reserved(rsv);
223 return (0);
224 }
225
226 /*
227 * Too few slots allocated here, so we need to extend or create
228 * the array.
229 */
230 if (rsv) {
231 /*
232 * Use the reserve passed in (assumed to be
233 * the right size).
234 */
235 newptr = rsv;
236 if (osd->osd_nslots != 0) {
237 memcpy(newptr, osd->osd_slots,
238 sizeof(void *) * osd->osd_nslots);
239 free(osd->osd_slots, M_OSD);
240 }
241 } else {
242 newptr = realloc(osd->osd_slots, sizeof(void *) * slot,
243 M_OSD, M_NOWAIT | M_ZERO);
244 if (newptr == NULL) {
245 rm_runlock(&osdm[type].osd_object_lock,
246 &tracker);
247 return (ENOMEM);
248 }
249 }
250 if (osd->osd_nslots == 0) {
251 /*
252 * First OSD for this object, so we need to put it
253 * onto the list.
254 */
255 mtx_lock(&osdm[type].osd_list_lock);
256 LIST_INSERT_HEAD(&osdm[type].osd_list, osd, osd_next);
257 mtx_unlock(&osdm[type].osd_list_lock);
258 OSD_DEBUG("Setting first slot (type=%u).", type);
259 } else
260 OSD_DEBUG("Growing slots array (type=%u).", type);
261 osd->osd_slots = newptr;
262 osd->osd_nslots = slot;
263 } else if (rsv)
264 osd_free_reserved(rsv);
265 OSD_DEBUG("Setting slot value (type=%u, slot=%u, value=%p).", type,
266 slot, value);
267 osd->osd_slots[slot - 1] = value;
268 rm_runlock(&osdm[type].osd_object_lock, &tracker);
269 return (0);
270 }
271
272 void
osd_free_reserved(void ** rsv)273 osd_free_reserved(void **rsv)
274 {
275
276 OSD_DEBUG("Discarding reserved slot array.");
277 free(rsv, M_OSD);
278 }
279
280 void *
osd_get_unlocked(u_int type,struct osd * osd,u_int slot)281 osd_get_unlocked(u_int type, struct osd *osd, u_int slot)
282 {
283 void *value;
284
285 KASSERT(osdm[type].osd_destructors[slot - 1] != NULL, ("Unused slot."));
286
287 if (slot > osd->osd_nslots) {
288 value = NULL;
289 OSD_DEBUG("Slot doesn't exist (type=%u, slot=%u).", type, slot);
290 } else {
291 value = atomic_load_ptr(&osd->osd_slots[slot - 1]);
292 OSD_DEBUG("Returning slot value (type=%u, slot=%u, value=%p).",
293 type, slot, value);
294 }
295 return (value);
296 }
297
298 void *
osd_get(u_int type,struct osd * osd,u_int slot)299 osd_get(u_int type, struct osd *osd, u_int slot)
300 {
301 struct rm_priotracker tracker;
302 void *value;
303
304 KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type."));
305 KASSERT(slot > 0, ("Invalid slot."));
306
307 rm_rlock(&osdm[type].osd_object_lock, &tracker);
308 value = osd_get_unlocked(type, osd, slot);
309 rm_runlock(&osdm[type].osd_object_lock, &tracker);
310 return (value);
311 }
312
313 void
osd_del(u_int type,struct osd * osd,u_int slot)314 osd_del(u_int type, struct osd *osd, u_int slot)
315 {
316 struct rm_priotracker tracker;
317
318 rm_rlock(&osdm[type].osd_object_lock, &tracker);
319 do_osd_del(type, osd, slot, 0);
320 rm_runlock(&osdm[type].osd_object_lock, &tracker);
321 }
322
323 static void
do_osd_del(u_int type,struct osd * osd,u_int slot,int list_locked)324 do_osd_del(u_int type, struct osd *osd, u_int slot, int list_locked)
325 {
326 int i;
327
328 KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type."));
329 KASSERT(slot > 0, ("Invalid slot."));
330 KASSERT(osdm[type].osd_destructors[slot - 1] != NULL, ("Unused slot."));
331
332 OSD_DEBUG("Deleting slot (type=%u, slot=%u).", type, slot);
333
334 if (slot > osd->osd_nslots) {
335 OSD_DEBUG("Slot doesn't exist (type=%u, slot=%u).", type, slot);
336 return;
337 }
338 if (osd->osd_slots[slot - 1] != NULL) {
339 osdm[type].osd_destructors[slot - 1](osd->osd_slots[slot - 1]);
340 osd->osd_slots[slot - 1] = NULL;
341 }
342 for (i = osd->osd_nslots - 1; i >= 0; i--) {
343 if (osd->osd_slots[i] != NULL) {
344 OSD_DEBUG("Slot still has a value (type=%u, slot=%u).",
345 type, i + 1);
346 break;
347 }
348 }
349 if (i == -1) {
350 /* No values left for this object. */
351 OSD_DEBUG("No more slots left (type=%u).", type);
352 if (!list_locked)
353 mtx_lock(&osdm[type].osd_list_lock);
354 LIST_REMOVE(osd, osd_next);
355 if (!list_locked)
356 mtx_unlock(&osdm[type].osd_list_lock);
357 free(osd->osd_slots, M_OSD);
358 osd->osd_slots = NULL;
359 osd->osd_nslots = 0;
360 } else if (slot == osd->osd_nslots) {
361 /* This was the last slot. */
362 osd->osd_slots = realloc(osd->osd_slots,
363 sizeof(void *) * (i + 1), M_OSD, M_NOWAIT | M_ZERO);
364 /*
365 * We always reallocate to smaller size, so we assume it will
366 * always succeed.
367 */
368 KASSERT(osd->osd_slots != NULL, ("realloc() failed"));
369 osd->osd_nslots = i + 1;
370 OSD_DEBUG("Reducing slots array to %u (type=%u).",
371 osd->osd_nslots, type);
372 }
373 }
374
375 int
osd_call(u_int type,u_int method,void * obj,void * data)376 osd_call(u_int type, u_int method, void *obj, void *data)
377 {
378 osd_method_t methodfun;
379 int error, i;
380
381 KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type."));
382 KASSERT(method < osdm[type].osd_nmethods, ("Invalid method."));
383
384 /*
385 * Call this method for every slot that defines it, stopping if an
386 * error is encountered.
387 */
388 error = 0;
389 sx_slock(&osdm[type].osd_module_lock);
390 for (i = 0; i < osdm[type].osd_ntslots; i++) {
391 /* Hole in the slot map; avoid dereferencing. */
392 if (osdm[type].osd_destructors[i] == NULL)
393 continue;
394 methodfun = osdm[type].osd_methods[i * osdm[type].osd_nmethods +
395 method];
396 if (methodfun != NULL && (error = methodfun(obj, data)) != 0)
397 break;
398 }
399 sx_sunlock(&osdm[type].osd_module_lock);
400 return (error);
401 }
402
403 void
osd_exit(u_int type,struct osd * osd)404 osd_exit(u_int type, struct osd *osd)
405 {
406 struct rm_priotracker tracker;
407 u_int i;
408
409 KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type."));
410
411 if (osd->osd_nslots == 0) {
412 KASSERT(osd->osd_slots == NULL, ("Non-null osd_slots."));
413 /* No OSD attached, just leave. */
414 return;
415 }
416
417 rm_rlock(&osdm[type].osd_object_lock, &tracker);
418 for (i = 1; i <= osd->osd_nslots; i++) {
419 if (osdm[type].osd_destructors[i - 1] != NULL)
420 do_osd_del(type, osd, i, 0);
421 else
422 OSD_DEBUG("Unused slot (type=%u, slot=%u).", type, i);
423 }
424 rm_runlock(&osdm[type].osd_object_lock, &tracker);
425 OSD_DEBUG("Object exit (type=%u).", type);
426 }
427
428 static void
osd_init(void * arg __unused)429 osd_init(void *arg __unused)
430 {
431 u_int i;
432
433 for (i = OSD_FIRST; i <= OSD_LAST; i++) {
434 sx_init(&osdm[i].osd_module_lock, "osd_module");
435 rm_init(&osdm[i].osd_object_lock, "osd_object");
436 mtx_init(&osdm[i].osd_list_lock, "osd_list", NULL, MTX_DEF);
437 LIST_INIT(&osdm[i].osd_list);
438 osdm[i].osd_destructors = NULL;
439 osdm[i].osd_ntslots = 0;
440 osdm[i].osd_methods = NULL;
441 }
442 }
443 SYSINIT(osd, SI_SUB_LOCK, SI_ORDER_ANY, osd_init, NULL);
444