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 #define OSD_METHOD(osdm, slot, method) \
77 ((osdm).osd_methods[((slot) - 1) * (osdm).osd_nmethods + (method)])
78
79 static void do_osd_del(u_int type, struct osd *osd, u_int slot,
80 int list_locked);
81
82 /*
83 * List of objects with OSD.
84 */
85 struct osd_master osdm[OSD_LAST + 1] = {
86 [OSD_JAIL] = { .osd_nmethods = PR_MAXMETHOD },
87 };
88
89 static void
osd_default_destructor(void * value __unused)90 osd_default_destructor(void *value __unused)
91 {
92 /* Do nothing. */
93 }
94
95 int
osd_register(u_int type,osd_destructor_t destructor,const osd_method_t * methods)96 osd_register(u_int type, osd_destructor_t destructor, const osd_method_t *methods)
97 {
98 void *newptr;
99 u_int i, m;
100
101 KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type."));
102
103 /*
104 * If no destructor is given, use default one. We need to use some
105 * destructor, because NULL destructor means unused slot.
106 */
107 if (destructor == NULL)
108 destructor = osd_default_destructor;
109
110 sx_xlock(&osdm[type].osd_module_lock);
111 /*
112 * First, we try to find unused slot.
113 */
114 for (i = 0; i < osdm[type].osd_ntslots; i++) {
115 if (osdm[type].osd_destructors[i] == NULL) {
116 OSD_DEBUG("Unused slot found (type=%u, slot=%u).",
117 type, i + 1);
118 break;
119 }
120 }
121 /*
122 * If no unused slot was found, allocate one.
123 */
124 if (i == osdm[type].osd_ntslots) {
125 osdm[type].osd_ntslots++;
126 if (osdm[type].osd_nmethods != 0)
127 osdm[type].osd_methods = realloc(osdm[type].osd_methods,
128 sizeof(osd_method_t) * osdm[type].osd_ntslots *
129 osdm[type].osd_nmethods, M_OSD, M_WAITOK);
130 newptr = malloc(sizeof(osd_destructor_t) *
131 osdm[type].osd_ntslots, M_OSD, M_WAITOK);
132 rm_wlock(&osdm[type].osd_object_lock);
133 bcopy(osdm[type].osd_destructors, newptr,
134 sizeof(osd_destructor_t) * i);
135 free(osdm[type].osd_destructors, M_OSD);
136 osdm[type].osd_destructors = newptr;
137 rm_wunlock(&osdm[type].osd_object_lock);
138 OSD_DEBUG("New slot allocated (type=%u, slot=%u).",
139 type, i + 1);
140 }
141
142 osdm[type].osd_destructors[i] = destructor;
143 if (osdm[type].osd_nmethods != 0) {
144 for (m = 0; m < osdm[type].osd_nmethods; m++)
145 OSD_METHOD(osdm[type], i + 1, m) =
146 methods != NULL ? methods[m] : NULL;
147 }
148 sx_xunlock(&osdm[type].osd_module_lock);
149 return (i + 1);
150 }
151
152 void
osd_deregister(u_int type,u_int slot)153 osd_deregister(u_int type, u_int slot)
154 {
155 struct osd *osd, *tosd;
156
157 KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type."));
158 KASSERT(slot > 0, ("Invalid slot."));
159
160 sx_xlock(&osdm[type].osd_module_lock);
161 rm_wlock(&osdm[type].osd_object_lock);
162 KASSERT(osdm[type].osd_destructors[slot - 1] != NULL, ("Unused slot."));
163
164 /*
165 * Free all OSD for the given slot.
166 */
167 mtx_lock(&osdm[type].osd_list_lock);
168 LIST_FOREACH_SAFE(osd, &osdm[type].osd_list, osd_next, tosd)
169 do_osd_del(type, osd, slot, 1);
170 mtx_unlock(&osdm[type].osd_list_lock);
171
172 /*
173 * Set destructor to NULL to free the slot. We don't bother actually
174 * freeing any memory here because we'll gracefully reuse any freed
175 * slots, and reallocating the arrays as a smaller chunk of memory isn't
176 * actually guaranteed to succeed. As such, we'll err on the side of
177 * caution and just leave it be since these are generally modestly sized
178 * allocations.
179 */
180 osdm[type].osd_destructors[slot - 1] = NULL;
181 OSD_DEBUG("Slot deregistration (type=%u, slot=%u).", type, slot);
182
183 #ifdef INVARIANTS
184 /*
185 * We trash the slot's osd_methods upon deregistration so that we take
186 * a fault if something calls them, rather than potentially
187 * inadvertently executing some arbitrary function if another module's
188 * been mapped over the one that deregistered.
189 */
190 for (u_int method = 0; method < osdm[type].osd_nmethods; method++) {
191 OSD_METHOD(osdm[type], slot, method) = (void *)0xdeadc0de;
192 }
193 #endif
194
195 rm_wunlock(&osdm[type].osd_object_lock);
196 sx_xunlock(&osdm[type].osd_module_lock);
197 }
198
199 int
osd_set(u_int type,struct osd * osd,u_int slot,void * value)200 osd_set(u_int type, struct osd *osd, u_int slot, void *value)
201 {
202
203 return (osd_set_reserved(type, osd, slot, NULL, value));
204 }
205
206 void **
osd_reserve(u_int slot)207 osd_reserve(u_int slot)
208 {
209
210 KASSERT(slot > 0, ("Invalid slot."));
211
212 OSD_DEBUG("Reserving slot array (slot=%u).", slot);
213 return (malloc(sizeof(void *) * slot, M_OSD, M_WAITOK | M_ZERO));
214 }
215
216 int
osd_set_reserved(u_int type,struct osd * osd,u_int slot,void ** rsv,void * value)217 osd_set_reserved(u_int type, struct osd *osd, u_int slot, void **rsv,
218 void *value)
219 {
220 struct rm_priotracker tracker;
221
222 KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type."));
223 KASSERT(slot > 0, ("Invalid slot."));
224
225 rm_rlock(&osdm[type].osd_object_lock, &tracker);
226 KASSERT(osdm[type].osd_destructors[slot - 1] != NULL, ("Unused slot."));
227
228 if (slot > osd->osd_nslots) {
229 void **newptr;
230
231 if (value == NULL) {
232 OSD_DEBUG(
233 "Not allocating null slot (type=%u, slot=%u).",
234 type, slot);
235 rm_runlock(&osdm[type].osd_object_lock, &tracker);
236 if (rsv)
237 osd_free_reserved(rsv);
238 return (0);
239 }
240
241 /*
242 * Too few slots allocated here, so we need to extend or create
243 * the array.
244 */
245 if (rsv) {
246 /*
247 * Use the reserve passed in (assumed to be
248 * the right size).
249 */
250 newptr = rsv;
251 if (osd->osd_nslots != 0) {
252 memcpy(newptr, osd->osd_slots,
253 sizeof(void *) * osd->osd_nslots);
254 free(osd->osd_slots, M_OSD);
255 }
256 } else {
257 newptr = realloc(osd->osd_slots, sizeof(void *) * slot,
258 M_OSD, M_NOWAIT | M_ZERO);
259 if (newptr == NULL) {
260 rm_runlock(&osdm[type].osd_object_lock,
261 &tracker);
262 return (ENOMEM);
263 }
264 }
265 if (osd->osd_nslots == 0) {
266 /*
267 * First OSD for this object, so we need to put it
268 * onto the list.
269 */
270 mtx_lock(&osdm[type].osd_list_lock);
271 LIST_INSERT_HEAD(&osdm[type].osd_list, osd, osd_next);
272 mtx_unlock(&osdm[type].osd_list_lock);
273 OSD_DEBUG("Setting first slot (type=%u).", type);
274 } else
275 OSD_DEBUG("Growing slots array (type=%u).", type);
276 osd->osd_slots = newptr;
277 osd->osd_nslots = slot;
278 } else if (rsv)
279 osd_free_reserved(rsv);
280 OSD_DEBUG("Setting slot value (type=%u, slot=%u, value=%p).", type,
281 slot, value);
282 osd->osd_slots[slot - 1] = value;
283 rm_runlock(&osdm[type].osd_object_lock, &tracker);
284 return (0);
285 }
286
287 void
osd_free_reserved(void ** rsv)288 osd_free_reserved(void **rsv)
289 {
290
291 OSD_DEBUG("Discarding reserved slot array.");
292 free(rsv, M_OSD);
293 }
294
295 void *
osd_get_unlocked(u_int type,struct osd * osd,u_int slot)296 osd_get_unlocked(u_int type, struct osd *osd, u_int slot)
297 {
298 void *value;
299
300 KASSERT(osdm[type].osd_destructors[slot - 1] != NULL, ("Unused slot."));
301
302 if (slot > osd->osd_nslots) {
303 value = NULL;
304 OSD_DEBUG("Slot doesn't exist (type=%u, slot=%u).", type, slot);
305 } else {
306 value = atomic_load_ptr(&osd->osd_slots[slot - 1]);
307 OSD_DEBUG("Returning slot value (type=%u, slot=%u, value=%p).",
308 type, slot, value);
309 }
310 return (value);
311 }
312
313 void *
osd_get(u_int type,struct osd * osd,u_int slot)314 osd_get(u_int type, struct osd *osd, u_int slot)
315 {
316 struct rm_priotracker tracker;
317 void *value;
318
319 KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type."));
320 KASSERT(slot > 0, ("Invalid slot."));
321
322 rm_rlock(&osdm[type].osd_object_lock, &tracker);
323 value = osd_get_unlocked(type, osd, slot);
324 rm_runlock(&osdm[type].osd_object_lock, &tracker);
325 return (value);
326 }
327
328 void
osd_del(u_int type,struct osd * osd,u_int slot)329 osd_del(u_int type, struct osd *osd, u_int slot)
330 {
331 struct rm_priotracker tracker;
332
333 rm_rlock(&osdm[type].osd_object_lock, &tracker);
334 do_osd_del(type, osd, slot, 0);
335 rm_runlock(&osdm[type].osd_object_lock, &tracker);
336 }
337
338 static void
do_osd_del(u_int type,struct osd * osd,u_int slot,int list_locked)339 do_osd_del(u_int type, struct osd *osd, u_int slot, int list_locked)
340 {
341 int i;
342
343 KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type."));
344 KASSERT(slot > 0, ("Invalid slot."));
345 KASSERT(osdm[type].osd_destructors[slot - 1] != NULL, ("Unused slot."));
346
347 OSD_DEBUG("Deleting slot (type=%u, slot=%u).", type, slot);
348
349 if (slot > osd->osd_nslots) {
350 OSD_DEBUG("Slot doesn't exist (type=%u, slot=%u).", type, slot);
351 return;
352 }
353 if (osd->osd_slots[slot - 1] != NULL) {
354 osdm[type].osd_destructors[slot - 1](osd->osd_slots[slot - 1]);
355 osd->osd_slots[slot - 1] = NULL;
356 }
357 for (i = osd->osd_nslots - 1; i >= 0; i--) {
358 if (osd->osd_slots[i] != NULL) {
359 OSD_DEBUG("Slot still has a value (type=%u, slot=%u).",
360 type, i + 1);
361 break;
362 }
363 }
364 if (i == -1) {
365 /* No values left for this object. */
366 OSD_DEBUG("No more slots left (type=%u).", type);
367 if (!list_locked)
368 mtx_lock(&osdm[type].osd_list_lock);
369 LIST_REMOVE(osd, osd_next);
370 if (!list_locked)
371 mtx_unlock(&osdm[type].osd_list_lock);
372 free(osd->osd_slots, M_OSD);
373 osd->osd_slots = NULL;
374 osd->osd_nslots = 0;
375 } else if (slot == osd->osd_nslots) {
376 /* This was the last slot. */
377 osd->osd_slots = realloc(osd->osd_slots,
378 sizeof(void *) * (i + 1), M_OSD, M_NOWAIT | M_ZERO);
379 /*
380 * We always reallocate to smaller size, so we assume it will
381 * always succeed.
382 */
383 KASSERT(osd->osd_slots != NULL, ("realloc() failed"));
384 osd->osd_nslots = i + 1;
385 OSD_DEBUG("Reducing slots array to %u (type=%u).",
386 osd->osd_nslots, type);
387 }
388 }
389
390 int
osd_call(u_int type,u_int method,void * obj,void * data)391 osd_call(u_int type, u_int method, void *obj, void *data)
392 {
393 osd_method_t methodfun;
394 int error, i;
395
396 KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type."));
397 KASSERT(method < osdm[type].osd_nmethods, ("Invalid method."));
398
399 /*
400 * Call this method for every slot that defines it, stopping if an
401 * error is encountered.
402 */
403 error = 0;
404 sx_slock(&osdm[type].osd_module_lock);
405 for (i = 0; i < osdm[type].osd_ntslots; i++) {
406 /* Hole in the slot map; avoid dereferencing. */
407 if (osdm[type].osd_destructors[i] == NULL)
408 continue;
409 methodfun = OSD_METHOD(osdm[type], i + 1, method);
410 if (methodfun != NULL && (error = methodfun(obj, data)) != 0)
411 break;
412 }
413 sx_sunlock(&osdm[type].osd_module_lock);
414 return (error);
415 }
416
417 void
osd_exit(u_int type,struct osd * osd)418 osd_exit(u_int type, struct osd *osd)
419 {
420 struct rm_priotracker tracker;
421 u_int i;
422
423 KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type."));
424
425 if (osd->osd_nslots == 0) {
426 KASSERT(osd->osd_slots == NULL, ("Non-null osd_slots."));
427 /* No OSD attached, just leave. */
428 return;
429 }
430
431 rm_rlock(&osdm[type].osd_object_lock, &tracker);
432 for (i = 1; i <= osd->osd_nslots; i++) {
433 if (osdm[type].osd_destructors[i - 1] != NULL)
434 do_osd_del(type, osd, i, 0);
435 else
436 OSD_DEBUG("Unused slot (type=%u, slot=%u).", type, i);
437 }
438 rm_runlock(&osdm[type].osd_object_lock, &tracker);
439 OSD_DEBUG("Object exit (type=%u).", type);
440 }
441
442 static void
osd_init(void * arg __unused)443 osd_init(void *arg __unused)
444 {
445 u_int i;
446
447 for (i = OSD_FIRST; i <= OSD_LAST; i++) {
448 sx_init(&osdm[i].osd_module_lock, "osd_module");
449 rm_init(&osdm[i].osd_object_lock, "osd_object");
450 mtx_init(&osdm[i].osd_list_lock, "osd_list", NULL, MTX_DEF);
451 LIST_INIT(&osdm[i].osd_list);
452 osdm[i].osd_destructors = NULL;
453 osdm[i].osd_ntslots = 0;
454 osdm[i].osd_methods = NULL;
455 }
456 }
457 SYSINIT(osd, SI_SUB_LOCK, SI_ORDER_ANY, osd_init, NULL);
458