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 #define kmalloc(bytes, zone, flags) calloc(bytes, 1) 62 #define lwkt_token_init(a, b) 63 #define lwkt_token_uninit(a) 64 #define kfree(ptr, flags) free(ptr) 65 #define KKASSERT(a) 66 #define panic(str, ...) assert(0) 67 #define min(a, b) (((a) < (b)) ? (a) : (b)) 68 #define max(a, b) (((a) > (b)) ? (a) : (b)) 69 70 int 71 main(int ac, char **av) 72 { 73 char buf[256]; 74 struct idr idr; 75 intptr_t generation = 0x10000000; 76 int error; 77 int id; 78 79 idr_init(&idr); 80 81 printf("cmd> "); 82 fflush(stdout); 83 while (fgets(buf, sizeof(buf), stdin) != NULL) { 84 if (sscanf(buf, "a %d", &id) == 1) { 85 for (;;) { 86 if (idr_pre_get(&idr, 0) == 0) { 87 fprintf(stderr, "pre_get failed\n"); 88 exit(1); 89 } 90 error = idr_get_new_above(&idr, 91 (void *)generation, 92 id, &id); 93 if (error == -EAGAIN) 94 continue; 95 if (error) { 96 fprintf(stderr, "get_new err %d\n", 97 error); 98 exit(1); 99 } 100 printf("allocated %d value %08x\n", 101 id, (int)generation); 102 ++generation; 103 break; 104 } 105 } else if (sscanf(buf, "f %d", &id) == 1) { 106 idr_remove(&idr, id); 107 } else if (sscanf(buf, "g %d", &id) == 1) { 108 void *res = idr_find(&idr, id); 109 printf("find %d res %p\n", id, res); 110 } 111 printf("cmd> "); 112 fflush(stdout); 113 } 114 return 0; 115 } 116 117 #else 118 119 #include <sys/idr.h> 120 #include <sys/kernel.h> 121 #include <sys/libkern.h> 122 #include <sys/malloc.h> 123 #include <sys/param.h> 124 #include <sys/systm.h> 125 #include <sys/spinlock2.h> 126 #include <sys/limits.h> 127 128 #endif 129 130 /* Must be 2^n - 1 */ 131 #define IDR_DEFAULT_SIZE 255 132 133 MALLOC_DEFINE(M_IDR, "idr", "Integer ID management"); 134 135 static void idr_grow(struct idr *idp, int want); 136 static void idr_reserve(struct idr *idp, int id, int incr); 137 static int idr_find_free(struct idr *idp, int want, int lim); 138 139 /* 140 * Number of nodes in right subtree, including the root. 141 */ 142 static __inline int 143 right_subtree_size(int n) 144 { 145 return (n ^ (n | (n + 1))); 146 } 147 148 /* 149 * Bigger ancestor. 150 */ 151 static __inline int 152 right_ancestor(int n) 153 { 154 return (n | (n + 1)); 155 } 156 157 /* 158 * Smaller ancestor. 159 */ 160 static __inline int 161 left_ancestor(int n) 162 { 163 return ((n & (n + 1)) - 1); 164 } 165 166 static __inline void 167 idrfixup(struct idr *idp, int id) 168 { 169 if (id < idp->idr_freeindex) { 170 idp->idr_freeindex = id; 171 } 172 while (idp->idr_lastindex >= 0 && 173 idp->idr_nodes[idp->idr_lastindex].data == NULL 174 ) { 175 --idp->idr_lastindex; 176 } 177 } 178 179 static __inline struct idr_node * 180 idr_get_node(struct idr *idp, int id) 181 { 182 struct idr_node *idrnp; 183 if (id < 0 || id >= idp->idr_count) 184 return (NULL); 185 idrnp = &idp->idr_nodes[id]; 186 if (idrnp->allocated == 0) 187 return (NULL); 188 return (idrnp); 189 } 190 191 static void 192 idr_reserve(struct idr *idp, int id, int incr) 193 { 194 while (id >= 0) { 195 idp->idr_nodes[id].allocated += incr; 196 KKASSERT(idp->idr_nodes[id].allocated >= 0); 197 id = left_ancestor(id); 198 } 199 } 200 201 static int 202 idr_find_free(struct idr *idp, int want, int lim) 203 { 204 int id, rsum, rsize, node; 205 206 /* 207 * Search for a free descriptor starting at the higher 208 * of want or fd_freefile. If that fails, consider 209 * expanding the ofile array. 210 * 211 * NOTE! the 'allocated' field is a cumulative recursive allocation 212 * count. If we happen to see a value of 0 then we can shortcut 213 * our search. Otherwise we run through through the tree going 214 * down branches we know have free descriptor(s) until we hit a 215 * leaf node. The leaf node will be free but will not necessarily 216 * have an allocated field of 0. 217 */ 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 int 354 idr_get_new(struct idr *idp, void *ptr, int *id) 355 { 356 return idr_get_new_above(idp, ptr, 0, id); 357 } 358 359 /* 360 * Grow the file table so it can hold through descriptor (want). 361 * 362 * Caller must hold a blockable lock. 363 */ 364 static void 365 idr_grow(struct idr *idp, int want) 366 { 367 struct idr_node *oldnodes, *newnodes; 368 int nf; 369 370 /* We want 2^n - 1 descriptors */ 371 nf = idp->idr_count; 372 do { 373 nf = 2 * nf + 1; 374 } while (nf <= want); 375 376 #ifdef USERLAND_TEST 377 printf("idr_grow: %d -> %d\n", idp->idr_count, nf); 378 #endif 379 380 /* Allocate a new zero'ed node array */ 381 newnodes = kmalloc(nf * sizeof(struct idr_node), 382 M_IDR, M_ZERO | M_WAITOK); 383 384 /* We might race another grow */ 385 if (nf <= idp->idr_count) { 386 kfree(newnodes, M_IDR); 387 return; 388 } 389 390 /* 391 * Copy existing nodes to the beginning of the new array 392 */ 393 oldnodes = idp->idr_nodes; 394 if (oldnodes) { 395 bcopy(oldnodes, newnodes, 396 idp->idr_count * sizeof(struct idr_node)); 397 } 398 idp->idr_nodes = newnodes; 399 idp->idr_count = nf; 400 401 if (oldnodes) { 402 kfree(oldnodes, M_IDR); 403 } 404 idp->idr_nexpands++; 405 } 406 407 void 408 idr_remove(struct idr *idp, int id) 409 { 410 void *ptr; 411 412 lwkt_gettoken(&idp->idr_token); 413 if (id < 0 || id >= idp->idr_count) { 414 lwkt_reltoken(&idp->idr_token); 415 return; 416 } 417 if ((ptr = idp->idr_nodes[id].data) == NULL) { 418 lwkt_reltoken(&idp->idr_token); 419 return; 420 } 421 idp->idr_nodes[id].data = NULL; 422 idr_reserve(idp, id, -1); 423 idrfixup(idp, id); 424 lwkt_reltoken(&idp->idr_token); 425 } 426 427 /* 428 * Remove all int allocations, leave array intact. 429 * 430 * Caller must hold a blockable lock (or be in a context where holding 431 * the spinlock is not relevant). 432 */ 433 void 434 idr_remove_all(struct idr *idp) 435 { 436 lwkt_gettoken(&idp->idr_token); 437 bzero(idp->idr_nodes, idp->idr_count * sizeof(struct idr_node)); 438 idp->idr_lastindex = -1; 439 idp->idr_freeindex = 0; 440 idp->idr_nexpands = 0; 441 idp->idr_maxwant = 0; 442 lwkt_reltoken(&idp->idr_token); 443 } 444 445 void 446 idr_destroy(struct idr *idp) 447 { 448 lwkt_token_uninit(&idp->idr_token); 449 if (idp->idr_nodes) { 450 kfree(idp->idr_nodes, M_IDR); 451 idp->idr_nodes = NULL; 452 } 453 bzero(idp, sizeof(*idp)); 454 } 455 456 void * 457 idr_find(struct idr *idp, int id) 458 { 459 void *ret; 460 461 if (id < 0 || id >= idp->idr_count) { 462 ret = NULL; 463 } else if (idp->idr_nodes[id].allocated == 0) { 464 ret = NULL; 465 } else { 466 ret = idp->idr_nodes[id].data; 467 } 468 return ret; 469 } 470 471 int 472 idr_for_each(struct idr *idp, int (*fn)(int id, void *p, void *data), 473 void *data) 474 { 475 int i, error = 0; 476 struct idr_node *nodes; 477 478 nodes = idp->idr_nodes; 479 for (i = 0; i < idp->idr_count; i++) { 480 if (nodes[i].data != NULL && nodes[i].allocated > 0) { 481 error = fn(i, nodes[i].data, data); 482 if (error != 0) 483 break; 484 } 485 } 486 return error; 487 } 488 489 void * 490 idr_replace(struct idr *idp, void *ptr, int id) 491 { 492 struct idr_node *idrnp; 493 void *ret; 494 495 lwkt_gettoken(&idp->idr_token); 496 idrnp = idr_get_node(idp, id); 497 if (idrnp == NULL || ptr == NULL) { 498 ret = NULL; 499 } else { 500 ret = idrnp->data; 501 idrnp->data = ptr; 502 } 503 lwkt_reltoken(&idp->idr_token); 504 return (ret); 505 } 506 507 void 508 idr_init(struct idr *idp) 509 { 510 bzero(idp, sizeof(struct idr)); 511 idp->idr_nodes = kmalloc(IDR_DEFAULT_SIZE * sizeof(struct idr_node), 512 M_IDR, M_WAITOK | M_ZERO); 513 idp->idr_count = IDR_DEFAULT_SIZE; 514 idp->idr_lastindex = -1; 515 idp->idr_maxwant = 0; 516 lwkt_token_init(&idp->idr_token, "idr token"); 517 } 518