FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_osd.c
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: releng/8.1/sys/kern/kern_osd.c 199583 2009-11-20 15:27:52Z jhb $");
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 static MALLOC_DEFINE(M_OSD, "osd", "Object Specific Data");
48
49 static int osd_debug = 0;
50 TUNABLE_INT("debug.osd", &osd_debug);
51 SYSCTL_INT(_debug, OID_AUTO, osd, CTLFLAG_RW, &osd_debug, 0, "OSD debug level");
52
53 #define OSD_DEBUG(...) do { \
54 if (osd_debug) { \
55 printf("OSD (%s:%u): ", __func__, __LINE__); \
56 printf(__VA_ARGS__); \
57 printf("\n"); \
58 } \
59 } while (0)
60
61 static void do_osd_del(u_int type, struct osd *osd, u_int slot,
62 int list_locked);
63
64 /*
65 * Lists of objects with OSD.
66 *
67 * Lock key:
68 * (m) osd_module_lock
69 * (o) osd_object_lock
70 * (l) osd_list_lock
71 */
72 static LIST_HEAD(, osd) osd_list[OSD_LAST + 1]; /* (m) */
73 static osd_method_t *osd_methods[OSD_LAST + 1]; /* (m) */
74 static u_int osd_nslots[OSD_LAST + 1]; /* (m) */
75 static osd_destructor_t *osd_destructors[OSD_LAST + 1]; /* (o) */
76 static const u_int osd_nmethods[OSD_LAST + 1] = {
77 [OSD_JAIL] = PR_MAXMETHOD,
78 };
79
80 static struct sx osd_module_lock[OSD_LAST + 1];
81 static struct rmlock osd_object_lock[OSD_LAST + 1];
82 static struct mtx osd_list_lock[OSD_LAST + 1];
83
84 static void
85 osd_default_destructor(void *value __unused)
86 {
87 /* Do nothing. */
88 }
89
90 int
91 osd_register(u_int type, osd_destructor_t destructor, osd_method_t *methods)
92 {
93 void *newptr;
94 u_int i, m;
95
96 KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type."));
97
98 /*
99 * If no destructor is given, use default one. We need to use some
100 * destructor, because NULL destructor means unused slot.
101 */
102 if (destructor == NULL)
103 destructor = osd_default_destructor;
104
105 sx_xlock(&osd_module_lock[type]);
106 /*
107 * First, we try to find unused slot.
108 */
109 for (i = 0; i < osd_nslots[type]; i++) {
110 if (osd_destructors[type][i] == NULL) {
111 OSD_DEBUG("Unused slot found (type=%u, slot=%u).",
112 type, i);
113 break;
114 }
115 }
116 /*
117 * If no unused slot was found, allocate one.
118 */
119 if (i == osd_nslots[type]) {
120 osd_nslots[type]++;
121 if (osd_nmethods[type] != 0)
122 osd_methods[type] = realloc(osd_methods[type],
123 sizeof(osd_method_t) * osd_nslots[type] *
124 osd_nmethods[type], M_OSD, M_WAITOK);
125 newptr = malloc(sizeof(osd_destructor_t) * osd_nslots[type],
126 M_OSD, M_WAITOK);
127 rm_wlock(&osd_object_lock[type]);
128 bcopy(osd_destructors[type], newptr,
129 sizeof(osd_destructor_t) * i);
130 free(osd_destructors[type], M_OSD);
131 osd_destructors[type] = newptr;
132 rm_wunlock(&osd_object_lock[type]);
133 OSD_DEBUG("New slot allocated (type=%u, slot=%u).",
134 type, i + 1);
135 }
136
137 osd_destructors[type][i] = destructor;
138 if (osd_nmethods[type] != 0) {
139 for (m = 0; m < osd_nmethods[type]; m++)
140 osd_methods[type][i * osd_nmethods[type] + m] =
141 methods != NULL ? methods[m] : NULL;
142 }
143 sx_xunlock(&osd_module_lock[type]);
144 return (i + 1);
145 }
146
147 void
148 osd_deregister(u_int type, u_int slot)
149 {
150 struct osd *osd, *tosd;
151
152 KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type."));
153 KASSERT(slot > 0, ("Invalid slot."));
154 KASSERT(osd_destructors[type][slot - 1] != NULL, ("Unused slot."));
155
156 sx_xlock(&osd_module_lock[type]);
157 rm_wlock(&osd_object_lock[type]);
158 /*
159 * Free all OSD for the given slot.
160 */
161 mtx_lock(&osd_list_lock[type]);
162 LIST_FOREACH_SAFE(osd, &osd_list[type], osd_next, tosd)
163 do_osd_del(type, osd, slot, 1);
164 mtx_unlock(&osd_list_lock[type]);
165 /*
166 * Set destructor to NULL to free the slot.
167 */
168 osd_destructors[type][slot - 1] = NULL;
169 if (slot == osd_nslots[type]) {
170 osd_nslots[type]--;
171 osd_destructors[type] = realloc(osd_destructors[type],
172 sizeof(osd_destructor_t) * osd_nslots[type], M_OSD,
173 M_NOWAIT | M_ZERO);
174 if (osd_nmethods[type] != 0)
175 osd_methods[type] = realloc(osd_methods[type],
176 sizeof(osd_method_t) * osd_nslots[type] *
177 osd_nmethods[type], M_OSD, M_NOWAIT | M_ZERO);
178 /*
179 * We always reallocate to smaller size, so we assume it will
180 * always succeed.
181 */
182 KASSERT(osd_destructors[type] != NULL &&
183 (osd_nmethods[type] == 0 || osd_methods[type] != NULL),
184 ("realloc() failed"));
185 OSD_DEBUG("Deregistration of the last slot (type=%u, slot=%u).",
186 type, slot);
187 } else {
188 OSD_DEBUG("Slot deregistration (type=%u, slot=%u).",
189 type, slot);
190 }
191 rm_wunlock(&osd_object_lock[type]);
192 sx_xunlock(&osd_module_lock[type]);
193 }
194
195 int
196 osd_set(u_int type, struct osd *osd, u_int slot, void *value)
197 {
198 struct rm_priotracker tracker;
199
200 KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type."));
201 KASSERT(slot > 0, ("Invalid slot."));
202 KASSERT(osd_destructors[type][slot - 1] != NULL, ("Unused slot."));
203
204 rm_rlock(&osd_object_lock[type], &tracker);
205 if (slot > osd->osd_nslots) {
206 if (value == NULL) {
207 OSD_DEBUG(
208 "Not allocating null slot (type=%u, slot=%u).",
209 type, slot);
210 rm_runlock(&osd_object_lock[type], &tracker);
211 return (0);
212 } else if (osd->osd_nslots == 0) {
213 /*
214 * First OSD for this object, so we need to allocate
215 * space and put it onto the list.
216 */
217 osd->osd_slots = malloc(sizeof(void *) * slot, M_OSD,
218 M_NOWAIT | M_ZERO);
219 if (osd->osd_slots == NULL) {
220 rm_runlock(&osd_object_lock[type], &tracker);
221 return (ENOMEM);
222 }
223 osd->osd_nslots = slot;
224 mtx_lock(&osd_list_lock[type]);
225 LIST_INSERT_HEAD(&osd_list[type], osd, osd_next);
226 mtx_unlock(&osd_list_lock[type]);
227 OSD_DEBUG("Setting first slot (type=%u).", type);
228 } else {
229 void *newptr;
230
231 /*
232 * Too few slots allocated here, needs to extend
233 * the array.
234 */
235 newptr = realloc(osd->osd_slots, sizeof(void *) * slot,
236 M_OSD, M_NOWAIT | M_ZERO);
237 if (newptr == NULL) {
238 rm_runlock(&osd_object_lock[type], &tracker);
239 return (ENOMEM);
240 }
241 osd->osd_slots = newptr;
242 osd->osd_nslots = slot;
243 OSD_DEBUG("Growing slots array (type=%u).", type);
244 }
245 }
246 OSD_DEBUG("Setting slot value (type=%u, slot=%u, value=%p).", type,
247 slot, value);
248 osd->osd_slots[slot - 1] = value;
249 rm_runlock(&osd_object_lock[type], &tracker);
250 return (0);
251 }
252
253 void *
254 osd_get(u_int type, struct osd *osd, u_int slot)
255 {
256 struct rm_priotracker tracker;
257 void *value;
258
259 KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type."));
260 KASSERT(slot > 0, ("Invalid slot."));
261 KASSERT(osd_destructors[type][slot - 1] != NULL, ("Unused slot."));
262
263 rm_rlock(&osd_object_lock[type], &tracker);
264 if (slot > osd->osd_nslots) {
265 value = NULL;
266 OSD_DEBUG("Slot doesn't exist (type=%u, slot=%u).", type, slot);
267 } else {
268 value = osd->osd_slots[slot - 1];
269 OSD_DEBUG("Returning slot value (type=%u, slot=%u, value=%p).",
270 type, slot, value);
271 }
272 rm_runlock(&osd_object_lock[type], &tracker);
273 return (value);
274 }
275
276 void
277 osd_del(u_int type, struct osd *osd, u_int slot)
278 {
279 struct rm_priotracker tracker;
280
281 rm_rlock(&osd_object_lock[type], &tracker);
282 do_osd_del(type, osd, slot, 0);
283 rm_runlock(&osd_object_lock[type], &tracker);
284 }
285
286 static void
287 do_osd_del(u_int type, struct osd *osd, u_int slot, int list_locked)
288 {
289 int i;
290
291 KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type."));
292 KASSERT(slot > 0, ("Invalid slot."));
293 KASSERT(osd_destructors[type][slot - 1] != NULL, ("Unused slot."));
294
295 OSD_DEBUG("Deleting slot (type=%u, slot=%u).", type, slot);
296
297 if (slot > osd->osd_nslots) {
298 OSD_DEBUG("Slot doesn't exist (type=%u, slot=%u).", type, slot);
299 return;
300 }
301 if (osd->osd_slots[slot - 1] != NULL) {
302 osd_destructors[type][slot - 1](osd->osd_slots[slot - 1]);
303 osd->osd_slots[slot - 1] = NULL;
304 }
305 for (i = osd->osd_nslots - 1; i >= 0; i--) {
306 if (osd->osd_slots[i] != NULL) {
307 OSD_DEBUG("Slot still has a value (type=%u, slot=%u).",
308 type, i + 1);
309 break;
310 }
311 }
312 if (i == -1) {
313 /* No values left for this object. */
314 OSD_DEBUG("No more slots left (type=%u).", type);
315 if (!list_locked)
316 mtx_lock(&osd_list_lock[type]);
317 LIST_REMOVE(osd, osd_next);
318 if (!list_locked)
319 mtx_unlock(&osd_list_lock[type]);
320 free(osd->osd_slots, M_OSD);
321 osd->osd_slots = NULL;
322 osd->osd_nslots = 0;
323 } else if (slot == osd->osd_nslots) {
324 /* This was the last slot. */
325 osd->osd_slots = realloc(osd->osd_slots,
326 sizeof(void *) * (i + 1), M_OSD, M_NOWAIT | M_ZERO);
327 /*
328 * We always reallocate to smaller size, so we assume it will
329 * always succeed.
330 */
331 KASSERT(osd->osd_slots != NULL, ("realloc() failed"));
332 osd->osd_nslots = i + 1;
333 OSD_DEBUG("Reducing slots array to %u (type=%u).",
334 osd->osd_nslots, type);
335 }
336 }
337
338 int
339 osd_call(u_int type, u_int method, void *obj, void *data)
340 {
341 osd_method_t methodfun;
342 int error, i;
343
344 KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type."));
345 KASSERT(method < osd_nmethods[type], ("Invalid method."));
346
347 /*
348 * Call this method for every slot that defines it, stopping if an
349 * error is encountered.
350 */
351 error = 0;
352 sx_slock(&osd_module_lock[type]);
353 for (i = 0; i < osd_nslots[type]; i++) {
354 methodfun =
355 osd_methods[type][i * osd_nmethods[type] + method];
356 if (methodfun != NULL && (error = methodfun(obj, data)) != 0)
357 break;
358 }
359 sx_sunlock(&osd_module_lock[type]);
360 return (error);
361 }
362
363 void
364 osd_exit(u_int type, struct osd *osd)
365 {
366 struct rm_priotracker tracker;
367 u_int i;
368
369 KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type."));
370
371 if (osd->osd_nslots == 0) {
372 KASSERT(osd->osd_slots == NULL, ("Non-null osd_slots."));
373 /* No OSD attached, just leave. */
374 return;
375 }
376
377 rm_rlock(&osd_object_lock[type], &tracker);
378 for (i = 1; i <= osd->osd_nslots; i++) {
379 if (osd_destructors[type][i - 1] != NULL)
380 do_osd_del(type, osd, i, 0);
381 else
382 OSD_DEBUG("Unused slot (type=%u, slot=%u).", type, i);
383 }
384 rm_runlock(&osd_object_lock[type], &tracker);
385 OSD_DEBUG("Object exit (type=%u).", type);
386 }
387
388 static void
389 osd_init(void *arg __unused)
390 {
391 u_int i;
392
393 for (i = OSD_FIRST; i <= OSD_LAST; i++) {
394 osd_nslots[i] = 0;
395 LIST_INIT(&osd_list[i]);
396 sx_init(&osd_module_lock[i], "osd_module");
397 rm_init(&osd_object_lock[i], "osd_object");
398 mtx_init(&osd_list_lock[i], "osd_list", NULL, MTX_DEF);
399 osd_destructors[i] = NULL;
400 osd_methods[i] = NULL;
401 }
402 }
403 SYSINIT(osd, SI_SUB_LOCK, SI_ORDER_ANY, osd_init, NULL);
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