1 /* $NetBSD: subr_bufq.c,v 1.29 2026/01/04 02:11:09 riastradh Exp $ */ 2 /* NetBSD: subr_disk.c,v 1.70 2005/08/20 12:00:01 yamt Exp $ */ 3 4 /*- 5 * Copyright (c) 1996, 1997, 1999, 2000 The NetBSD Foundation, Inc. 6 * All rights reserved. 7 * 8 * This code is derived from software contributed to The NetBSD Foundation 9 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility, 10 * NASA Ames Research Center. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 23 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 24 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 25 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 26 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 27 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 28 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 29 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 30 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 31 * POSSIBILITY OF SUCH DAMAGE. 32 */ 33 34 /* 35 * Copyright (c) 1982, 1986, 1988, 1993 36 * The Regents of the University of California. All rights reserved. 37 * (c) UNIX System Laboratories, Inc. 38 * All or some portions of this file are derived from material licensed 39 * to the University of California by American Telephone and Telegraph 40 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 41 * the permission of UNIX System Laboratories, Inc. 42 * 43 * Redistribution and use in source and binary forms, with or without 44 * modification, are permitted provided that the following conditions 45 * are met: 46 * 1. Redistributions of source code must retain the above copyright 47 * notice, this list of conditions and the following disclaimer. 48 * 2. Redistributions in binary form must reproduce the above copyright 49 * notice, this list of conditions and the following disclaimer in the 50 * documentation and/or other materials provided with the distribution. 51 * 3. Neither the name of the University nor the names of its contributors 52 * may be used to endorse or promote products derived from this software 53 * without specific prior written permission. 54 * 55 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 56 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 57 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 58 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 59 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 60 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 61 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 62 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 63 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 64 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 65 * SUCH DAMAGE. 66 * 67 * @(#)ufs_disksubr.c 8.5 (Berkeley) 1/21/94 68 */ 69 70 #include <sys/cdefs.h> 71 __KERNEL_RCSID(0, "$NetBSD: subr_bufq.c,v 1.29 2026/01/04 02:11:09 riastradh Exp $"); 72 73 #include <sys/param.h> 74 #include <sys/types.h> 75 76 #include <sys/buf.h> 77 #include <sys/bufq.h> 78 #include <sys/bufq_impl.h> 79 #include <sys/kmem.h> 80 #include <sys/module.h> 81 #include <sys/sdt.h> 82 #include <sys/sysctl.h> 83 #include <sys/systm.h> 84 85 #define STRAT_MATCH(id, bs) (strcmp((id), (bs)->bs_name) == 0) 86 87 static void sysctl_kern_bufq_strategies_setup(struct sysctllog **); 88 static SLIST_HEAD(, bufq_strat) bufq_strat_list = 89 SLIST_HEAD_INITIALIZER(bufq_strat_list); 90 91 static kmutex_t bufq_mutex; 92 93 static struct sysctllog *sysctllog; 94 95 void 96 bufq_init(void) 97 { 98 99 mutex_init(&bufq_mutex, MUTEX_DEFAULT, IPL_NONE); 100 sysctl_kern_bufq_strategies_setup(&sysctllog); 101 } 102 103 int 104 bufq_register(struct bufq_strat *bs) 105 { 106 107 mutex_enter(&bufq_mutex); 108 SLIST_INSERT_HEAD(&bufq_strat_list, bs, bs_next); 109 bs->bs_refcnt = 0; 110 mutex_exit(&bufq_mutex); 111 112 return 0; 113 } 114 115 int 116 bufq_unregister(struct bufq_strat *bs) 117 { 118 119 mutex_enter(&bufq_mutex); 120 if (bs->bs_refcnt != 0) { 121 mutex_exit(&bufq_mutex); 122 return SET_ERROR(EBUSY); 123 } 124 SLIST_REMOVE(&bufq_strat_list, bs, bufq_strat, bs_next); 125 mutex_exit(&bufq_mutex); 126 127 return 0; 128 } 129 130 /* 131 * Create a device buffer queue. 132 */ 133 int 134 bufq_alloc(struct bufq_state **bufqp, const char *strategy, int flags) 135 { 136 struct bufq_strat *bsp, *it; 137 struct bufq_state *bufq; 138 int error = 0; 139 u_int gen; 140 bool found_exact; 141 char strategy_module_name[MAXPATHLEN]; 142 143 KASSERT((flags & BUFQ_EXACT) == 0 || strategy != BUFQ_STRAT_ANY); 144 145 switch (flags & BUFQ_SORT_MASK) { 146 case BUFQ_SORT_RAWBLOCK: 147 case BUFQ_SORT_CYLINDER: 148 break; 149 case 0: 150 /* 151 * for strategies which don't care about block numbers. 152 * eg. fcfs 153 */ 154 flags |= BUFQ_SORT_RAWBLOCK; 155 break; 156 default: 157 panic("bufq_alloc: sort out of range"); 158 } 159 160 /* 161 * select strategy. 162 * if a strategy specified by flags is found, use it. 163 * otherwise, select one with the largest bs_prio. 164 */ 165 mutex_enter(&bufq_mutex); 166 do { 167 gen = module_gen; 168 bsp = NULL; 169 found_exact = false; 170 171 SLIST_FOREACH(it, &bufq_strat_list, bs_next) { 172 if (strategy != BUFQ_STRAT_ANY && 173 STRAT_MATCH(strategy, (it))) { 174 bsp = it; 175 found_exact = true; 176 break; 177 } 178 if (bsp == NULL || (it)->bs_prio > bsp->bs_prio) 179 bsp = it; 180 } 181 if (strategy == BUFQ_STRAT_ANY || found_exact) 182 break; 183 184 /* Try to autoload the bufq strategy module */ 185 strlcpy(strategy_module_name, "bufq_", 186 sizeof(strategy_module_name)); 187 strlcat(strategy_module_name, strategy, 188 sizeof(strategy_module_name)); 189 mutex_exit(&bufq_mutex); 190 (void) module_autoload(strategy_module_name, MODULE_CLASS_BUFQ); 191 mutex_enter(&bufq_mutex); 192 } while (gen != module_gen); 193 194 if (bsp == NULL) { 195 panic("bufq_alloc: no strategy"); 196 } 197 if (strategy != BUFQ_STRAT_ANY && !found_exact) { 198 if ((flags & BUFQ_EXACT)) { 199 error = SET_ERROR(ENOENT); 200 mutex_exit(&bufq_mutex); 201 goto out; 202 } 203 #if defined(DEBUG) 204 printf("bufq_alloc: '%s' is not available. using '%s'.\n", 205 strategy, bsp->bs_name); 206 #endif 207 } 208 #if defined(BUFQ_DEBUG) 209 /* XXX aprint? */ 210 printf("bufq_alloc: using '%s'\n", bsp->bs_name); 211 #endif 212 213 bsp->bs_refcnt++; 214 mutex_exit(&bufq_mutex); 215 *bufqp = bufq = kmem_zalloc(sizeof(*bufq), KM_SLEEP); 216 bufq->bq_flags = flags; 217 bufq->bq_strat = bsp; 218 (*bsp->bs_initfn)(bufq); 219 220 out: 221 return error; 222 } 223 224 void 225 bufq_put(struct bufq_state *bufq, struct buf *bp) 226 { 227 228 (*bufq->bq_put)(bufq, bp); 229 } 230 231 struct buf * 232 bufq_get(struct bufq_state *bufq) 233 { 234 235 return (*bufq->bq_get)(bufq, 1); 236 } 237 238 struct buf * 239 bufq_peek(struct bufq_state *bufq) 240 { 241 242 return (*bufq->bq_get)(bufq, 0); 243 } 244 245 struct buf * 246 bufq_cancel(struct bufq_state *bufq, struct buf *bp) 247 { 248 249 return (*bufq->bq_cancel)(bufq, bp); 250 } 251 252 /* 253 * Drain a device buffer queue. 254 */ 255 void 256 bufq_drain(struct bufq_state *bufq) 257 { 258 struct buf *bp; 259 260 while ((bp = bufq_get(bufq)) != NULL) { 261 bp->b_error = SET_ERROR(EIO); 262 bp->b_resid = bp->b_bcount; 263 biodone(bp); 264 } 265 } 266 267 /* 268 * Destroy a device buffer queue. 269 */ 270 void 271 bufq_free(struct bufq_state *bufq) 272 { 273 274 KASSERT(bufq_peek(bufq) == NULL); 275 276 bufq->bq_fini(bufq); 277 278 mutex_enter(&bufq_mutex); 279 bufq->bq_strat->bs_refcnt--; 280 mutex_exit(&bufq_mutex); 281 282 kmem_free(bufq, sizeof(*bufq)); 283 } 284 285 /* 286 * get a strategy identifier of a buffer queue. 287 */ 288 const char * 289 bufq_getstrategyname(struct bufq_state *bufq) 290 { 291 292 return bufq->bq_strat->bs_name; 293 } 294 295 /* 296 * move all requests on a buffer queue to another. 297 */ 298 void 299 bufq_move(struct bufq_state *dst, struct bufq_state *src) 300 { 301 struct buf *bp; 302 303 while ((bp = bufq_get(src)) != NULL) { 304 bufq_put(dst, bp); 305 } 306 } 307 308 static int 309 docopy(char *buf, size_t *bufoffp, size_t buflen, 310 const char *datap, size_t datalen) 311 { 312 int error = 0; 313 314 if (buf != NULL && datalen > 0) { 315 316 if (*bufoffp + datalen > buflen) { 317 goto out; 318 } 319 error = copyout(datap, buf + *bufoffp, datalen); 320 if (error) { 321 goto out; 322 } 323 } 324 out: 325 if (error == 0) { 326 *bufoffp += datalen; 327 } 328 329 return error; 330 } 331 332 static int 333 docopystr(char *buf, size_t *bufoffp, size_t buflen, const char *datap) 334 { 335 336 return docopy(buf, bufoffp, buflen, datap, strlen(datap)); 337 } 338 339 static int 340 docopynul(char *buf, size_t *bufoffp, size_t buflen) 341 { 342 343 return docopy(buf, bufoffp, buflen, "", 1); 344 } 345 346 /* 347 * sysctl function that will print all bufq strategies 348 * currently available to the kernel. 349 */ 350 static int 351 sysctl_kern_bufq_strategies(SYSCTLFN_ARGS) 352 { 353 const struct bufq_strat *bq_strat; 354 const char *delim = ""; 355 size_t off = 0; 356 size_t buflen = *oldlenp; 357 int error; 358 359 SLIST_FOREACH(bq_strat, &bufq_strat_list, bs_next) { 360 error = docopystr(oldp, &off, buflen, delim); 361 if (error) { 362 goto out; 363 } 364 error = docopystr(oldp, &off, buflen, (bq_strat)->bs_name); 365 if (error) { 366 goto out; 367 } 368 delim = " "; 369 } 370 371 /* In case there are no registered strategies ... */ 372 if (off == 0) { 373 error = docopystr(oldp, &off, buflen, "NULL"); 374 if (error) { 375 goto out; 376 } 377 } 378 379 /* NUL terminate */ 380 error = docopynul(oldp, &off, buflen); 381 out: 382 *oldlenp = off; 383 return error; 384 } 385 386 static void 387 sysctl_kern_bufq_strategies_setup(struct sysctllog **clog) 388 { 389 const struct sysctlnode *node; 390 391 node = NULL; 392 sysctl_createv(clog, 0, NULL, &node, 393 CTLFLAG_PERMANENT, 394 CTLTYPE_NODE, "bufq", 395 SYSCTL_DESCR("buffer queue subtree"), 396 NULL, 0, NULL, 0, 397 CTL_KERN, CTL_CREATE, CTL_EOL); 398 if (node != NULL) { 399 sysctl_createv(clog, 0, NULL, NULL, 400 CTLFLAG_PERMANENT, 401 CTLTYPE_STRING, "strategies", 402 SYSCTL_DESCR("List of bufq strategies present"), 403 sysctl_kern_bufq_strategies, 0, NULL, 0, 404 CTL_KERN, node->sysctl_num, CTL_CREATE, CTL_EOL); 405 } 406 } 407
Indexes created Sat Feb 21 16:20:20 UTC 2026