FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_osd.c
1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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/cdefs.h>
30 __FBSDID("$FreeBSD: releng/12.0/sys/kern/kern_osd.c 326271 2017-11-27 15:20:12Z pfg $");
31
32 #include <sys/param.h>
33 #include <sys/kernel.h>
34 #include <sys/systm.h>
35 #include <sys/sysctl.h>
36 #include <sys/errno.h>
37 #include <sys/jail.h>
38 #include <sys/malloc.h>
39 #include <sys/lock.h>
40 #include <sys/mutex.h>
41 #include <sys/rmlock.h>
42 #include <sys/sx.h>
43 #include <sys/queue.h>
44 #include <sys/proc.h>
45 #include <sys/osd.h>
46
47 /* OSD (Object Specific Data) */
48
49 /*
50 * Lock key:
51 * (m) osd_module_lock
52 * (o) osd_object_lock
53 * (l) osd_list_lock
54 */
55 struct osd_master {
56 struct sx osd_module_lock;
57 struct rmlock osd_object_lock;
58 struct mtx osd_list_lock;
59 LIST_HEAD(, osd) osd_list; /* (l) */
60 osd_destructor_t *osd_destructors; /* (o) */
61 osd_method_t *osd_methods; /* (m) */
62 u_int osd_ntslots; /* (m) */
63 const u_int osd_nmethods;
64 };
65
66 static MALLOC_DEFINE(M_OSD, "osd", "Object Specific Data");
67
68 static int osd_debug = 0;
69 SYSCTL_INT(_debug, OID_AUTO, osd, CTLFLAG_RWTUN, &osd_debug, 0, "OSD debug level");
70
71 #define OSD_DEBUG(...) do { \
72 if (osd_debug) { \
73 printf("OSD (%s:%u): ", __func__, __LINE__); \
74 printf(__VA_ARGS__); \
75 printf("\n"); \
76 } \
77 } while (0)
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
90 osd_default_destructor(void *value __unused)
91 {
92 /* Do nothing. */
93 }
94
95 int
96 osd_register(u_int type, osd_destructor_t destructor, 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);
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 osdm[type].osd_methods[i * osdm[type].osd_nmethods + m]
146 = methods != NULL ? methods[m] : NULL;
147 }
148 sx_xunlock(&osdm[type].osd_module_lock);
149 return (i + 1);
150 }
151
152 void
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 KASSERT(osdm[type].osd_destructors[slot - 1] != NULL, ("Unused slot."));
160
161 sx_xlock(&osdm[type].osd_module_lock);
162 rm_wlock(&osdm[type].osd_object_lock);
163 /*
164 * Free all OSD for the given slot.
165 */
166 mtx_lock(&osdm[type].osd_list_lock);
167 LIST_FOREACH_SAFE(osd, &osdm[type].osd_list, osd_next, tosd)
168 do_osd_del(type, osd, slot, 1);
169 mtx_unlock(&osdm[type].osd_list_lock);
170 /*
171 * Set destructor to NULL to free the slot.
172 */
173 osdm[type].osd_destructors[slot - 1] = NULL;
174 if (slot == osdm[type].osd_ntslots) {
175 osdm[type].osd_ntslots--;
176 osdm[type].osd_destructors = realloc(osdm[type].osd_destructors,
177 sizeof(osd_destructor_t) * osdm[type].osd_ntslots, M_OSD,
178 M_NOWAIT | M_ZERO);
179 if (osdm[type].osd_nmethods != 0)
180 osdm[type].osd_methods = realloc(osdm[type].osd_methods,
181 sizeof(osd_method_t) * osdm[type].osd_ntslots *
182 osdm[type].osd_nmethods, M_OSD, M_NOWAIT | M_ZERO);
183 /*
184 * We always reallocate to smaller size, so we assume it will
185 * always succeed.
186 */
187 KASSERT(osdm[type].osd_destructors != NULL &&
188 (osdm[type].osd_nmethods == 0 ||
189 osdm[type].osd_methods != NULL), ("realloc() failed"));
190 OSD_DEBUG("Deregistration of the last slot (type=%u, slot=%u).",
191 type, slot);
192 } else {
193 OSD_DEBUG("Slot deregistration (type=%u, slot=%u).",
194 type, slot);
195 }
196 rm_wunlock(&osdm[type].osd_object_lock);
197 sx_xunlock(&osdm[type].osd_module_lock);
198 }
199
200 int
201 osd_set(u_int type, struct osd *osd, u_int slot, void *value)
202 {
203
204 return (osd_set_reserved(type, osd, slot, NULL, value));
205 }
206
207 void **
208 osd_reserve(u_int slot)
209 {
210
211 KASSERT(slot > 0, ("Invalid slot."));
212
213 OSD_DEBUG("Reserving slot array (slot=%u).", slot);
214 return (malloc(sizeof(void *) * slot, M_OSD, M_WAITOK | M_ZERO));
215 }
216
217 int
218 osd_set_reserved(u_int type, struct osd *osd, u_int slot, void **rsv,
219 void *value)
220 {
221 struct rm_priotracker tracker;
222
223 KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type."));
224 KASSERT(slot > 0, ("Invalid slot."));
225 KASSERT(osdm[type].osd_destructors[slot - 1] != NULL, ("Unused slot."));
226
227 rm_rlock(&osdm[type].osd_object_lock, &tracker);
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
288 osd_free_reserved(void **rsv)
289 {
290
291 OSD_DEBUG("Discarding reserved slot array.");
292 free(rsv, M_OSD);
293 }
294
295 void *
296 osd_get(u_int type, struct osd *osd, u_int slot)
297 {
298 struct rm_priotracker tracker;
299 void *value;
300
301 KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type."));
302 KASSERT(slot > 0, ("Invalid slot."));
303 KASSERT(osdm[type].osd_destructors[slot - 1] != NULL, ("Unused slot."));
304
305 rm_rlock(&osdm[type].osd_object_lock, &tracker);
306 if (slot > osd->osd_nslots) {
307 value = NULL;
308 OSD_DEBUG("Slot doesn't exist (type=%u, slot=%u).", type, slot);
309 } else {
310 value = osd->osd_slots[slot - 1];
311 OSD_DEBUG("Returning slot value (type=%u, slot=%u, value=%p).",
312 type, slot, value);
313 }
314 rm_runlock(&osdm[type].osd_object_lock, &tracker);
315 return (value);
316 }
317
318 void
319 osd_del(u_int type, struct osd *osd, u_int slot)
320 {
321 struct rm_priotracker tracker;
322
323 rm_rlock(&osdm[type].osd_object_lock, &tracker);
324 do_osd_del(type, osd, slot, 0);
325 rm_runlock(&osdm[type].osd_object_lock, &tracker);
326 }
327
328 static void
329 do_osd_del(u_int type, struct osd *osd, u_int slot, int list_locked)
330 {
331 int i;
332
333 KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type."));
334 KASSERT(slot > 0, ("Invalid slot."));
335 KASSERT(osdm[type].osd_destructors[slot - 1] != NULL, ("Unused slot."));
336
337 OSD_DEBUG("Deleting slot (type=%u, slot=%u).", type, slot);
338
339 if (slot > osd->osd_nslots) {
340 OSD_DEBUG("Slot doesn't exist (type=%u, slot=%u).", type, slot);
341 return;
342 }
343 if (osd->osd_slots[slot - 1] != NULL) {
344 osdm[type].osd_destructors[slot - 1](osd->osd_slots[slot - 1]);
345 osd->osd_slots[slot - 1] = NULL;
346 }
347 for (i = osd->osd_nslots - 1; i >= 0; i--) {
348 if (osd->osd_slots[i] != NULL) {
349 OSD_DEBUG("Slot still has a value (type=%u, slot=%u).",
350 type, i + 1);
351 break;
352 }
353 }
354 if (i == -1) {
355 /* No values left for this object. */
356 OSD_DEBUG("No more slots left (type=%u).", type);
357 if (!list_locked)
358 mtx_lock(&osdm[type].osd_list_lock);
359 LIST_REMOVE(osd, osd_next);
360 if (!list_locked)
361 mtx_unlock(&osdm[type].osd_list_lock);
362 free(osd->osd_slots, M_OSD);
363 osd->osd_slots = NULL;
364 osd->osd_nslots = 0;
365 } else if (slot == osd->osd_nslots) {
366 /* This was the last slot. */
367 osd->osd_slots = realloc(osd->osd_slots,
368 sizeof(void *) * (i + 1), M_OSD, M_NOWAIT | M_ZERO);
369 /*
370 * We always reallocate to smaller size, so we assume it will
371 * always succeed.
372 */
373 KASSERT(osd->osd_slots != NULL, ("realloc() failed"));
374 osd->osd_nslots = i + 1;
375 OSD_DEBUG("Reducing slots array to %u (type=%u).",
376 osd->osd_nslots, type);
377 }
378 }
379
380 int
381 osd_call(u_int type, u_int method, void *obj, void *data)
382 {
383 osd_method_t methodfun;
384 int error, i;
385
386 KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type."));
387 KASSERT(method < osdm[type].osd_nmethods, ("Invalid method."));
388
389 /*
390 * Call this method for every slot that defines it, stopping if an
391 * error is encountered.
392 */
393 error = 0;
394 sx_slock(&osdm[type].osd_module_lock);
395 for (i = 0; i < osdm[type].osd_ntslots; i++) {
396 methodfun = osdm[type].osd_methods[i * osdm[type].osd_nmethods +
397 method];
398 if (methodfun != NULL && (error = methodfun(obj, data)) != 0)
399 break;
400 }
401 sx_sunlock(&osdm[type].osd_module_lock);
402 return (error);
403 }
404
405 void
406 osd_exit(u_int type, struct osd *osd)
407 {
408 struct rm_priotracker tracker;
409 u_int i;
410
411 KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type."));
412
413 if (osd->osd_nslots == 0) {
414 KASSERT(osd->osd_slots == NULL, ("Non-null osd_slots."));
415 /* No OSD attached, just leave. */
416 return;
417 }
418
419 rm_rlock(&osdm[type].osd_object_lock, &tracker);
420 for (i = 1; i <= osd->osd_nslots; i++) {
421 if (osdm[type].osd_destructors[i - 1] != NULL)
422 do_osd_del(type, osd, i, 0);
423 else
424 OSD_DEBUG("Unused slot (type=%u, slot=%u).", type, i);
425 }
426 rm_runlock(&osdm[type].osd_object_lock, &tracker);
427 OSD_DEBUG("Object exit (type=%u).", type);
428 }
429
430 static void
431 osd_init(void *arg __unused)
432 {
433 u_int i;
434
435 for (i = OSD_FIRST; i <= OSD_LAST; i++) {
436 sx_init(&osdm[i].osd_module_lock, "osd_module");
437 rm_init(&osdm[i].osd_object_lock, "osd_object");
438 mtx_init(&osdm[i].osd_list_lock, "osd_list", NULL, MTX_DEF);
439 LIST_INIT(&osdm[i].osd_list);
440 osdm[i].osd_destructors = NULL;
441 osdm[i].osd_ntslots = 0;
442 osdm[i].osd_methods = NULL;
443 }
444 }
445 SYSINIT(osd, SI_SUB_LOCK, SI_ORDER_ANY, osd_init, NULL);
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