1 /* 2 * Copyright (c) 2005-2012 The DragonFly Project. 3 * Copyright (c) 2013 François Tigeot 4 * Copyright (c) 2013 Matthew Dillon 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The DragonFly Project 8 * by Jeffrey Hsu. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in 18 * the documentation and/or other materials provided with the 19 * distribution. 20 * 3. Neither the name of The DragonFly Project nor the names of its 21 * contributors may be used to endorse or promote products derived 22 * from this software without specific, prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 25 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 26 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 27 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 28 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 29 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, 30 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 31 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 32 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 33 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 34 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35 * SUCH DAMAGE. 36 */ 37 38 #ifdef USERLAND_TEST 39 /* 40 * Testing: 41 * 42 * cc -I. -DUSERLAND_TEST libkern/linux_idr.c -o /tmp/idr -g 43 */ 44 45 #define _KERNEL 46 #define _KERNEL_STRUCTURES 47 #define KLD_MODULE 48 #include <stdio.h> 49 #include <stdlib.h> 50 #include <unistd.h> 51 #include <string.h> 52 #include <limits.h> 53 #include <assert.h> 54 #include <sys/idr.h> 55 #include <sys/errno.h> 56 57 #undef MALLOC_DEFINE 58 #define MALLOC_DEFINE(a, b, c) 59 #define lwkt_gettoken(x) 60 #define lwkt_reltoken(x) 61 #undef kmalloc 62 #define kmalloc(bytes, zone, flags) calloc(bytes, 1) 63 #define lwkt_token_init(a, b) 64 #define lwkt_token_uninit(a) 65 #define kfree(ptr, flags) free(ptr) 66 #define KKASSERT(a) 67 #define panic(str, ...) assert(0) 68 #define min(a, b) (((a) < (b)) ? (a) : (b)) 69 #define max(a, b) (((a) > (b)) ? (a) : (b)) 70 71 int 72 main(int ac, char **av) 73 { 74 char buf[256]; 75 struct idr idr; 76 intptr_t generation = 0x0; 77 int error; 78 int id; 79 80 idr_init(&idr); 81 82 printf("cmd> "); 83 fflush(stdout); 84 while (fgets(buf, sizeof(buf), stdin) != NULL) { 85 if (sscanf(buf, "a %d", &id) == 1) { 86 for (;;) { 87 if (idr_pre_get(&idr, 0) == 0) { 88 fprintf(stderr, "pre_get failed\n"); 89 exit(1); 90 } 91 error = idr_get_new_above(&idr, 92 (void *)generation, 93 id, &id); 94 if (error == -EAGAIN) 95 continue; 96 if (error) { 97 fprintf(stderr, "get_new err %d\n", 98 error); 99 exit(1); 100 } 101 printf("allocated %d value %08x\n", 102 id, (int)generation); 103 ++generation; 104 break; 105 } 106 } else if (sscanf(buf, "f %d", &id) == 1) { 107 idr_remove(&idr, id); 108 } else if (sscanf(buf, "g %d", &id) == 1) { 109 void *res = idr_find(&idr, id); 110 printf("find %d res %p\n", id, res); 111 } 112 printf("cmd> "); 113 fflush(stdout); 114 } 115 return 0; 116 } 117 118 #else 119 120 #include <sys/idr.h> 121 #include <sys/kernel.h> 122 #include <sys/libkern.h> 123 #include <sys/malloc.h> 124 #include <sys/param.h> 125 #include <sys/systm.h> 126 #include <sys/spinlock2.h> 127 #include <sys/limits.h> 128 129 #endif 130 131 /* Must be 2^n - 1 */ 132 #define IDR_DEFAULT_SIZE 255 133 134 MALLOC_DEFINE(M_IDR, "idr", "Integer ID management"); 135 136 static void idr_grow(struct idr *idp, int want); 137 static void idr_reserve(struct idr *idp, int id, int incr); 138 static int idr_find_free(struct idr *idp, int want, int lim); 139 140 /* 141 * Number of nodes in right subtree, including the root. 142 */ 143 static __inline int 144 right_subtree_size(int n) 145 { 146 return (n ^ (n | (n + 1))); 147 } 148 149 /* 150 * Bigger ancestor. 151 */ 152 static __inline int 153 right_ancestor(int n) 154 { 155 return (n | (n + 1)); 156 } 157 158 /* 159 * Smaller ancestor. 160 */ 161 static __inline int 162 left_ancestor(int n) 163 { 164 return ((n & (n + 1)) - 1); 165 } 166 167 static __inline void 168 idrfixup(struct idr *idp, int id) 169 { 170 if (id < idp->idr_freeindex) { 171 idp->idr_freeindex = id; 172 } 173 while (idp->idr_lastindex >= 0 && 174 idp->idr_nodes[idp->idr_lastindex].data == NULL 175 ) { 176 --idp->idr_lastindex; 177 } 178 } 179 180 static __inline struct idr_node * 181 idr_get_node(struct idr *idp, int id) 182 { 183 struct idr_node *idrnp; 184 if (id < 0 || id >= idp->idr_count) 185 return (NULL); 186 idrnp = &idp->idr_nodes[id]; 187 if (idrnp->allocated == 0) 188 return (NULL); 189 return (idrnp); 190 } 191 192 static void 193 idr_reserve(struct idr *idp, int id, int incr) 194 { 195 while (id >= 0) { 196 idp->idr_nodes[id].allocated += incr; 197 KKASSERT(idp->idr_nodes[id].allocated >= 0); 198 id = left_ancestor(id); 199 } 200 } 201 202 static int 203 idr_find_free(struct idr *idp, int want, int lim) 204 { 205 int id, rsum, rsize, node; 206 207 /* 208 * Search for a free descriptor starting at the higher 209 * of want or fd_freefile. If that fails, consider 210 * expanding the ofile array. 211 * 212 * NOTE! the 'allocated' field is a cumulative recursive allocation 213 * count. If we happen to see a value of 0 then we can shortcut 214 * our search. Otherwise we run through through the tree going 215 * down branches we know have free descriptor(s) until we hit a 216 * leaf node. The leaf node will be free but will not necessarily 217 * have an allocated field of 0. 218 */ 219 /* move up the tree looking for a subtree with a free node */ 220 for (id = max(want, idp->idr_freeindex); id < min(idp->idr_count, lim); 221 id = right_ancestor(id)) { 222 if (idp->idr_nodes[id].allocated == 0) 223 return (id); 224 225 rsize = right_subtree_size(id); 226 if (idp->idr_nodes[id].allocated == rsize) 227 continue; /* right subtree full */ 228 229 /* 230 * Free fd is in the right subtree of the tree rooted at fd. 231 * Call that subtree R. Look for the smallest (leftmost) 232 * subtree of R with an unallocated fd: continue moving 233 * down the left branch until encountering a full left 234 * subtree, then move to the right. 235 */ 236 for (rsum = 0, rsize /= 2; rsize > 0; rsize /= 2) { 237 node = id + rsize; 238 rsum += idp->idr_nodes[node].allocated; 239 if (idp->idr_nodes[id].allocated == rsum + rsize) { 240 id = node; /* move to the right */ 241 if (idp->idr_nodes[node].allocated == 0) 242 return (id); 243 rsum = 0; 244 } 245 } 246 return (id); 247 } 248 return (-1); 249 } 250 251 /* 252 * Blocking pre-get support, allows callers to use idr_pre_get() in 253 * combination with idr_get_new_above() such that idr_get_new_above() 254 * can be called safely with a spinlock held. 255 * 256 * Returns 0 on failure, 1 on success. 257 * 258 * Caller must hold a blockable lock. 259 */ 260 int 261 idr_pre_get(struct idr *idp, __unused unsigned gfp_mask) 262 { 263 int want = idp->idr_maxwant; 264 int lim = INT_MAX; 265 int result = 1; /* success */ 266 int id; 267 268 KKASSERT(mycpu->gd_spinlocks == 0); 269 lwkt_gettoken(&idp->idr_token); 270 for (;;) { 271 /* 272 * Grow if necessary (or if forced by the loop) 273 */ 274 if (want >= idp->idr_count) 275 idr_grow(idp, want); 276 277 /* 278 * Check if a spot is available, break and return 0 if true, 279 * unless the available spot is beyond our limit. It is 280 * possible to exceed the limit due to the way array growth 281 * works. 282 * 283 * XXX we assume that the caller uses a consistent <sid> such 284 * that the idr_maxwant field is correct, otherwise we 285 * may believe that a slot is available but the caller then 286 * fails in idr_get_new_above() and loops. 287 */ 288 id = idr_find_free(idp, idp->idr_maxwant, lim); 289 if (id != -1) { 290 if (id >= lim) 291 result = 0; /* failure */ 292 break; 293 } 294 295 /* 296 * Return ENOSPC if our limit has been reached, otherwise 297 * loop and force growth. 298 */ 299 if (idp->idr_count >= lim) { 300 result = 0; /* failure */ 301 break; 302 } 303 want = idp->idr_count; 304 } 305 lwkt_reltoken(&idp->idr_token); 306 return result; 307 } 308 309 /* 310 * Allocate an integer. If -EAGAIN is returned the caller should loop 311 * and call idr_pre_get() with no locks held, and then retry the call 312 * to idr_get_new_above(). 313 * 314 * Can be safely called with spinlocks held. 315 */ 316 int 317 idr_get_new_above(struct idr *idp, void *ptr, int sid, int *id) 318 { 319 int resid; 320 321 /* 322 * NOTE! Because the idp is initialized with a non-zero count, 323 * sid might be < idp->idr_count but idr_maxwant might not 324 * yet be initialized. So check both cases. 325 */ 326 lwkt_gettoken(&idp->idr_token); 327 if (sid >= idp->idr_count || idp->idr_maxwant < sid) { 328 idp->idr_maxwant = max(idp->idr_maxwant, sid); 329 lwkt_reltoken(&idp->idr_token); 330 return -EAGAIN; 331 } 332 333 resid = idr_find_free(idp, sid, INT_MAX); 334 if (resid == -1) { 335 lwkt_reltoken(&idp->idr_token); 336 return -EAGAIN; 337 } 338 339 if (resid >= idp->idr_count) 340 panic("idr_get_new_above(): illegal resid %d", resid); 341 if (resid > idp->idr_lastindex) 342 idp->idr_lastindex = resid; 343 if (sid <= idp->idr_freeindex) 344 idp->idr_freeindex = resid; 345 *id = resid; 346 idr_reserve(idp, resid, 1); 347 idp->idr_nodes[resid].data = ptr; 348 349 lwkt_reltoken(&idp->idr_token); 350 return (0); 351 } 352 353 /* 354 * start: minimum id, inclusive 355 * end: maximum id, exclusive or INT_MAX if end is negative 356 */ 357 int 358 idr_alloc(struct idr *idp, void *ptr, int start, int end, unsigned gfp_mask) 359 { 360 int lim = end > 0 ? end - 1 : INT_MAX; 361 int want = start; 362 int result, id; 363 364 if (start < 0) 365 return -EINVAL; 366 367 if (lim < start) 368 return -ENOSPC; 369 370 lwkt_gettoken(&idp->idr_token); 371 372 grow_again: 373 if (want >= idp->idr_count) 374 idr_grow(idp, want); 375 376 /* 377 * Check if a spot is available, break and return 0 if true, 378 * unless the available spot is beyond our limit. It is 379 * possible to exceed the limit due to the way array growth 380 * works. 381 */ 382 id = idr_find_free(idp, start, INT_MAX); 383 if (id == -1) { 384 want = idp->idr_count; 385 goto grow_again; 386 } 387 388 if (id > lim) { 389 result = -ENOSPC; 390 goto done; 391 } 392 393 if (id >= idp->idr_count) 394 panic("idr_alloc(): illegal resid %d", id); 395 if (id > idp->idr_lastindex) 396 idp->idr_lastindex = id; 397 if (start <= idp->idr_freeindex) 398 idp->idr_freeindex = id; 399 result = id; 400 idr_reserve(idp, id, 1); 401 idp->idr_nodes[id].data = ptr; 402 403 done: 404 lwkt_reltoken(&idp->idr_token); 405 return result; 406 } 407 408 int 409 idr_get_new(struct idr *idp, void *ptr, int *id) 410 { 411 return idr_get_new_above(idp, ptr, 0, id); 412 } 413 414 /* 415 * Grow the file table so it can hold through descriptor (want). 416 * 417 * Caller must hold a blockable lock. 418 */ 419 static void 420 idr_grow(struct idr *idp, int want) 421 { 422 struct idr_node *oldnodes, *newnodes; 423 int nf; 424 425 /* We want 2^n - 1 descriptors */ 426 nf = idp->idr_count; 427 do { 428 nf = 2 * nf + 1; 429 } while (nf <= want); 430 431 #ifdef USERLAND_TEST 432 printf("idr_grow: %d -> %d\n", idp->idr_count, nf); 433 #endif 434 435 /* Allocate a new zero'ed node array */ 436 newnodes = kmalloc(nf * sizeof(struct idr_node), 437 M_IDR, M_ZERO | M_WAITOK); 438 439 /* We might race another grow */ 440 if (nf <= idp->idr_count) { 441 kfree(newnodes, M_IDR); 442 return; 443 } 444 445 /* 446 * Copy existing nodes to the beginning of the new array 447 */ 448 oldnodes = idp->idr_nodes; 449 if (oldnodes) { 450 bcopy(oldnodes, newnodes, 451 idp->idr_count * sizeof(struct idr_node)); 452 } 453 idp->idr_nodes = newnodes; 454 idp->idr_count = nf; 455 456 if (oldnodes) { 457 kfree(oldnodes, M_IDR); 458 } 459 idp->idr_nexpands++; 460 } 461 462 void * 463 idr_remove(struct idr *idp, int id) 464 { 465 void *ptr; 466 467 lwkt_gettoken(&idp->idr_token); 468 if (id < 0 || id >= idp->idr_count) { 469 lwkt_reltoken(&idp->idr_token); 470 return NULL; 471 } 472 if (idp->idr_nodes[id].allocated == 0) { 473 lwkt_reltoken(&idp->idr_token); 474 return NULL; 475 } 476 ptr = idp->idr_nodes[id].data; 477 idp->idr_nodes[id].data = NULL; 478 idr_reserve(idp, id, -1); 479 idrfixup(idp, id); 480 lwkt_reltoken(&idp->idr_token); 481 482 return ptr; 483 } 484 485 /* 486 * Remove all int allocations, leave array intact. 487 * 488 * Caller must hold a blockable lock (or be in a context where holding 489 * the spinlock is not relevant). 490 */ 491 void 492 idr_remove_all(struct idr *idp) 493 { 494 lwkt_gettoken(&idp->idr_token); 495 bzero(idp->idr_nodes, idp->idr_count * sizeof(struct idr_node)); 496 idp->idr_lastindex = -1; 497 idp->idr_freeindex = 0; 498 idp->idr_nexpands = 0; 499 idp->idr_maxwant = 0; 500 lwkt_reltoken(&idp->idr_token); 501 } 502 503 void 504 idr_destroy(struct idr *idp) 505 { 506 lwkt_token_uninit(&idp->idr_token); 507 if (idp->idr_nodes) { 508 kfree(idp->idr_nodes, M_IDR); 509 idp->idr_nodes = NULL; 510 } 511 bzero(idp, sizeof(*idp)); 512 } 513 514 void * 515 idr_find(struct idr *idp, int id) 516 { 517 void *ret; 518 519 if (id < 0 || id >= idp->idr_count) { 520 ret = NULL; 521 } else if (idp->idr_nodes[id].allocated == 0) { 522 ret = NULL; 523 } else { 524 ret = idp->idr_nodes[id].data; 525 } 526 return ret; 527 } 528 529 int 530 idr_for_each(struct idr *idp, int (*fn)(int id, void *p, void *data), 531 void *data) 532 { 533 int i, error = 0; 534 struct idr_node *nodes; 535 536 nodes = idp->idr_nodes; 537 for (i = 0; i < idp->idr_count; i++) { 538 if (nodes[i].data != NULL && nodes[i].allocated > 0) { 539 error = fn(i, nodes[i].data, data); 540 if (error != 0) 541 break; 542 } 543 } 544 return error; 545 } 546 547 void * 548 idr_replace(struct idr *idp, void *ptr, int id) 549 { 550 struct idr_node *idrnp; 551 void *ret; 552 553 lwkt_gettoken(&idp->idr_token); 554 idrnp = idr_get_node(idp, id); 555 if (idrnp == NULL) { 556 ret = NULL; 557 } else { 558 ret = idrnp->data; 559 idrnp->data = ptr; 560 } 561 lwkt_reltoken(&idp->idr_token); 562 return (ret); 563 } 564 565 void 566 idr_init(struct idr *idp) 567 { 568 bzero(idp, sizeof(struct idr)); 569 idp->idr_nodes = kmalloc(IDR_DEFAULT_SIZE * sizeof(struct idr_node), 570 M_IDR, M_WAITOK | M_ZERO); 571 idp->idr_count = IDR_DEFAULT_SIZE; 572 idp->idr_lastindex = -1; 573 idp->idr_maxwant = 0; 574 lwkt_token_init(&idp->idr_token, "idr token"); 575 } 576