Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_osd.c
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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; /* (l) */ 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 TUNABLE_INT("debug.osd", &osd_debug); 68 SYSCTL_INT(_debug, OID_AUTO, osd, CTLFLAG_RW, &osd_debug, 0, "OSD debug level"); 69 70 #define OSD_DEBUG(...) do { \ 71 if (osd_debug) { \ 72 printf("OSD (%s:%u): ", __func__, __LINE__); \ 73 printf(__VA_ARGS__); \ 74 printf("\n"); \ 75 } \ 76 } while (0) 77 78 static void do_osd_del(u_int type, struct osd *osd, u_int slot, 79 int list_locked); 80 81 /* 82 * List of objects with OSD. 83 */ 84 struct osd_master osdm[OSD_LAST + 1] = { 85 [OSD_JAIL] = { .osd_nmethods = PR_MAXMETHOD }, 86 }; 87 88 static void 89 osd_default_destructor(void *value __unused) 90 { 91 /* Do nothing. */ 92 } 93 94 int 95 osd_register(u_int type, osd_destructor_t destructor, osd_method_t *methods) 96 { 97 void *newptr; 98 u_int i, m; 99 100 KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type.")); 101 102 /* 103 * If no destructor is given, use default one. We need to use some 104 * destructor, because NULL destructor means unused slot. 105 */ 106 if (destructor == NULL) 107 destructor = osd_default_destructor; 108 109 sx_xlock(&osdm[type].osd_module_lock); 110 /* 111 * First, we try to find unused slot. 112 */ 113 for (i = 0; i < osdm[type].osd_ntslots; i++) { 114 if (osdm[type].osd_destructors[i] == NULL) { 115 OSD_DEBUG("Unused slot found (type=%u, slot=%u).", 116 type, i); 117 break; 118 } 119 } 120 /* 121 * If no unused slot was found, allocate one. 122 */ 123 if (i == osdm[type].osd_ntslots) { 124 osdm[type].osd_ntslots++; 125 if (osdm[type].osd_nmethods != 0) 126 osdm[type].osd_methods = realloc(osdm[type].osd_methods, 127 sizeof(osd_method_t) * osdm[type].osd_ntslots * 128 osdm[type].osd_nmethods, M_OSD, M_WAITOK); 129 newptr = malloc(sizeof(osd_destructor_t) * 130 osdm[type].osd_ntslots, M_OSD, M_WAITOK); 131 rm_wlock(&osdm[type].osd_object_lock); 132 bcopy(osdm[type].osd_destructors, newptr, 133 sizeof(osd_destructor_t) * i); 134 free(osdm[type].osd_destructors, M_OSD); 135 osdm[type].osd_destructors = newptr; 136 rm_wunlock(&osdm[type].osd_object_lock); 137 OSD_DEBUG("New slot allocated (type=%u, slot=%u).", 138 type, i + 1); 139 } 140 141 osdm[type].osd_destructors[i] = destructor; 142 if (osdm[type].osd_nmethods != 0) { 143 for (m = 0; m < osdm[type].osd_nmethods; m++) 144 osdm[type].osd_methods[i * osdm[type].osd_nmethods + m] 145 = methods != NULL ? methods[m] : NULL; 146 } 147 sx_xunlock(&osdm[type].osd_module_lock); 148 return (i + 1); 149 } 150 151 void 152 osd_deregister(u_int type, u_int slot) 153 { 154 struct osd *osd, *tosd; 155 156 KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type.")); 157 KASSERT(slot > 0, ("Invalid slot.")); 158 KASSERT(osdm[type].osd_destructors[slot - 1] != NULL, ("Unused slot.")); 159 160 sx_xlock(&osdm[type].osd_module_lock); 161 rm_wlock(&osdm[type].osd_object_lock); 162 /* 163 * Free all OSD for the given slot. 164 */ 165 mtx_lock(&osdm[type].osd_list_lock); 166 LIST_FOREACH_SAFE(osd, &osdm[type].osd_list, osd_next, tosd) 167 do_osd_del(type, osd, slot, 1); 168 mtx_unlock(&osdm[type].osd_list_lock); 169 /* 170 * Set destructor to NULL to free the slot. 171 */ 172 osdm[type].osd_destructors[slot - 1] = NULL; 173 if (slot == osdm[type].osd_ntslots) { 174 osdm[type].osd_ntslots--; 175 osdm[type].osd_destructors = realloc(osdm[type].osd_destructors, 176 sizeof(osd_destructor_t) * osdm[type].osd_ntslots, M_OSD, 177 M_NOWAIT | M_ZERO); 178 if (osdm[type].osd_nmethods != 0) 179 osdm[type].osd_methods = realloc(osdm[type].osd_methods, 180 sizeof(osd_method_t) * osdm[type].osd_ntslots * 181 osdm[type].osd_nmethods, M_OSD, M_NOWAIT | M_ZERO); 182 /* 183 * We always reallocate to smaller size, so we assume it will 184 * always succeed. 185 */ 186 KASSERT(osdm[type].osd_destructors != NULL && 187 (osdm[type].osd_nmethods == 0 || 188 osdm[type].osd_methods != NULL), ("realloc() failed")); 189 OSD_DEBUG("Deregistration of the last slot (type=%u, slot=%u).", 190 type, slot); 191 } else { 192 OSD_DEBUG("Slot deregistration (type=%u, slot=%u).", 193 type, slot); 194 } 195 rm_wunlock(&osdm[type].osd_object_lock); 196 sx_xunlock(&osdm[type].osd_module_lock); 197 } 198 199 int 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 * 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 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 KASSERT(osdm[type].osd_destructors[slot - 1] != NULL, ("Unused slot.")); 225 226 rm_rlock(&osdm[type].osd_object_lock, &tracker); 227 if (slot > osd->osd_nslots) { 228 void *newptr; 229 230 if (value == NULL) { 231 OSD_DEBUG( 232 "Not allocating null slot (type=%u, slot=%u).", 233 type, slot); 234 rm_runlock(&osdm[type].osd_object_lock, &tracker); 235 if (rsv) 236 osd_free_reserved(rsv); 237 return (0); 238 } 239 240 /* 241 * Too few slots allocated here, so we need to extend or create 242 * the array. 243 */ 244 if (rsv) { 245 /* 246 * Use the reserve passed in (assumed to be 247 * the right size). 248 */ 249 newptr = rsv; 250 if (osd->osd_nslots != 0) { 251 memcpy(newptr, osd->osd_slots, 252 sizeof(void *) * osd->osd_nslots); 253 free(osd->osd_slots, M_OSD); 254 } 255 } else { 256 newptr = realloc(osd->osd_slots, sizeof(void *) * slot, 257 M_OSD, M_NOWAIT | M_ZERO); 258 if (newptr == NULL) { 259 rm_runlock(&osdm[type].osd_object_lock, 260 &tracker); 261 return (ENOMEM); 262 } 263 } 264 if (osd->osd_nslots == 0) { 265 /* 266 * First OSD for this object, so we need to put it 267 * onto the list. 268 */ 269 mtx_lock(&osdm[type].osd_list_lock); 270 LIST_INSERT_HEAD(&osdm[type].osd_list, osd, osd_next); 271 mtx_unlock(&osdm[type].osd_list_lock); 272 OSD_DEBUG("Setting first slot (type=%u).", type); 273 } else 274 OSD_DEBUG("Growing slots array (type=%u).", type); 275 osd->osd_slots = newptr; 276 osd->osd_nslots = slot; 277 } else if (rsv) 278 osd_free_reserved(rsv); 279 OSD_DEBUG("Setting slot value (type=%u, slot=%u, value=%p).", type, 280 slot, value); 281 osd->osd_slots[slot - 1] = value; 282 rm_runlock(&osdm[type].osd_object_lock, &tracker); 283 return (0); 284 } 285 286 void 287 osd_free_reserved(void *rsv) 288 { 289 290 OSD_DEBUG("Discarding reserved slot array."); 291 free(rsv, M_OSD); 292 } 293 294 void * 295 osd_get(u_int type, struct osd *osd, u_int slot) 296 { 297 struct rm_priotracker tracker; 298 void *value; 299 300 KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type.")); 301 KASSERT(slot > 0, ("Invalid slot.")); 302 KASSERT(osdm[type].osd_destructors[slot - 1] != NULL, ("Unused slot.")); 303 304 rm_rlock(&osdm[type].osd_object_lock, &tracker); 305 if (slot > osd->osd_nslots) { 306 value = NULL; 307 OSD_DEBUG("Slot doesn't exist (type=%u, slot=%u).", type, slot); 308 } else { 309 value = osd->osd_slots[slot - 1]; 310 OSD_DEBUG("Returning slot value (type=%u, slot=%u, value=%p).", 311 type, slot, value); 312 } 313 rm_runlock(&osdm[type].osd_object_lock, &tracker); 314 return (value); 315 } 316 317 void 318 osd_del(u_int type, struct osd *osd, u_int slot) 319 { 320 struct rm_priotracker tracker; 321 322 rm_rlock(&osdm[type].osd_object_lock, &tracker); 323 do_osd_del(type, osd, slot, 0); 324 rm_runlock(&osdm[type].osd_object_lock, &tracker); 325 } 326 327 static void 328 do_osd_del(u_int type, struct osd *osd, u_int slot, int list_locked) 329 { 330 int i; 331 332 KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type.")); 333 KASSERT(slot > 0, ("Invalid slot.")); 334 KASSERT(osdm[type].osd_destructors[slot - 1] != NULL, ("Unused slot.")); 335 336 OSD_DEBUG("Deleting slot (type=%u, slot=%u).", type, slot); 337 338 if (slot > osd->osd_nslots) { 339 OSD_DEBUG("Slot doesn't exist (type=%u, slot=%u).", type, slot); 340 return; 341 } 342 if (osd->osd_slots[slot - 1] != NULL) { 343 osdm[type].osd_destructors[slot - 1](osd->osd_slots[slot - 1]); 344 osd->osd_slots[slot - 1] = NULL; 345 } 346 for (i = osd->osd_nslots - 1; i >= 0; i--) { 347 if (osd->osd_slots[i] != NULL) { 348 OSD_DEBUG("Slot still has a value (type=%u, slot=%u).", 349 type, i + 1); 350 break; 351 } 352 } 353 if (i == -1) { 354 /* No values left for this object. */ 355 OSD_DEBUG("No more slots left (type=%u).", type); 356 if (!list_locked) 357 mtx_lock(&osdm[type].osd_list_lock); 358 LIST_REMOVE(osd, osd_next); 359 if (!list_locked) 360 mtx_unlock(&osdm[type].osd_list_lock); 361 free(osd->osd_slots, M_OSD); 362 osd->osd_slots = NULL; 363 osd->osd_nslots = 0; 364 } else if (slot == osd->osd_nslots) { 365 /* This was the last slot. */ 366 osd->osd_slots = realloc(osd->osd_slots, 367 sizeof(void *) * (i + 1), M_OSD, M_NOWAIT | M_ZERO); 368 /* 369 * We always reallocate to smaller size, so we assume it will 370 * always succeed. 371 */ 372 KASSERT(osd->osd_slots != NULL, ("realloc() failed")); 373 osd->osd_nslots = i + 1; 374 OSD_DEBUG("Reducing slots array to %u (type=%u).", 375 osd->osd_nslots, type); 376 } 377 } 378 379 int 380 osd_call(u_int type, u_int method, void *obj, void *data) 381 { 382 osd_method_t methodfun; 383 int error, i; 384 385 KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type.")); 386 KASSERT(method < osdm[type].osd_nmethods, ("Invalid method.")); 387 388 /* 389 * Call this method for every slot that defines it, stopping if an 390 * error is encountered. 391 */ 392 error = 0; 393 sx_slock(&osdm[type].osd_module_lock); 394 for (i = 0; i < osdm[type].osd_ntslots; i++) { 395 methodfun = osdm[type].osd_methods[i * osdm[type].osd_nmethods + 396 method]; 397 if (methodfun != NULL && (error = methodfun(obj, data)) != 0) 398 break; 399 } 400 sx_sunlock(&osdm[type].osd_module_lock); 401 return (error); 402 } 403 404 void 405 osd_exit(u_int type, struct osd *osd) 406 { 407 struct rm_priotracker tracker; 408 u_int i; 409 410 KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type.")); 411 412 if (osd->osd_nslots == 0) { 413 KASSERT(osd->osd_slots == NULL, ("Non-null osd_slots.")); 414 /* No OSD attached, just leave. */ 415 return; 416 } 417 418 rm_rlock(&osdm[type].osd_object_lock, &tracker); 419 for (i = 1; i <= osd->osd_nslots; i++) { 420 if (osdm[type].osd_destructors[i - 1] != NULL) 421 do_osd_del(type, osd, i, 0); 422 else 423 OSD_DEBUG("Unused slot (type=%u, slot=%u).", type, i); 424 } 425 rm_runlock(&osdm[type].osd_object_lock, &tracker); 426 OSD_DEBUG("Object exit (type=%u).", type); 427 } 428 429 static void 430 osd_init(void *arg __unused) 431 { 432 u_int i; 433 434 for (i = OSD_FIRST; i <= OSD_LAST; i++) { 435 sx_init(&osdm[i].osd_module_lock, "osd_module"); 436 rm_init(&osdm[i].osd_object_lock, "osd_object"); 437 mtx_init(&osdm[i].osd_list_lock, "osd_list", NULL, MTX_DEF); 438 LIST_INIT(&osdm[i].osd_list); 439 osdm[i].osd_destructors = NULL; 440 osdm[i].osd_ntslots = 0; 441 osdm[i].osd_methods = NULL; 442 } 443 } 444 SYSINIT(osd, SI_SUB_LOCK, SI_ORDER_ANY, osd_init, NULL);
Cache object: f7e48d9e171a4be899476a2722bc96a3
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