subr_bufq.c revision 1.22
1 /* $NetBSD: subr_bufq.c,v 1.22 2016/11/16 00:46:46 pgoyette 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 1.22 2016/11/16 00:46:46 pgoyette Exp $"); 72 73 #include <sys/param.h> 74 #include <sys/systm.h> 75 #include <sys/buf.h> 76 #include <sys/bufq.h> 77 #include <sys/bufq_impl.h> 78 #include <sys/kmem.h> 79 #include <sys/sysctl.h> 80 #include <sys/module.h> 81 82 #define STRAT_MATCH(id, bs) (strcmp((id), (bs)->bs_name) == 0) 83 84 static void sysctl_kern_bufq_strategies_setup(struct sysctllog **); 85 static SLIST_HEAD(, bufq_strat) bufq_strat_list; 86 87 static kmutex_t bufq_mutex; 88 89 static struct sysctllog *sysctllog; 90 91 void 92 bufq_init(void) 93 { 94 95 mutex_init(&bufq_mutex, MUTEX_DEFAULT, IPL_NONE); 96 SLIST_INIT(&bufq_strat_list); 97 sysctl_kern_bufq_strategies_setup(&sysctllog); 98 } 99 100 int 101 bufq_register(struct bufq_strat *bs) 102 { 103 104 mutex_enter(&bufq_mutex); 105 SLIST_INSERT_HEAD(&bufq_strat_list, bs, bs_next); 106 bs->bs_refcnt = 0; 107 mutex_exit(&bufq_mutex); 108 109 return 0; 110 } 111 112 int 113 bufq_unregister(struct bufq_strat *bs) 114 { 115 116 mutex_enter(&bufq_mutex); 117 if (bs->bs_refcnt != 0) { 118 mutex_exit(&bufq_mutex); 119 return EBUSY; 120 } 121 SLIST_REMOVE(&bufq_strat_list, bs, bufq_strat, bs_next); 122 mutex_exit(&bufq_mutex); 123 124 return 0; 125 } 126 127 /* 128 * Create a device buffer queue. 129 */ 130 int 131 bufq_alloc(struct bufq_state **bufqp, const char *strategy, int flags) 132 { 133 struct bufq_strat *bsp, *it; 134 struct bufq_state *bufq; 135 int error = 0; 136 u_int gen; 137 bool found_exact; 138 char module_name[MAXPATHLEN]; 139 140 KASSERT((flags & BUFQ_EXACT) == 0 || strategy != BUFQ_STRAT_ANY); 141 142 switch (flags & BUFQ_SORT_MASK) { 143 case BUFQ_SORT_RAWBLOCK: 144 case BUFQ_SORT_CYLINDER: 145 break; 146 case 0: 147 /* 148 * for strategies which don't care about block numbers. 149 * eg. fcfs 150 */ 151 flags |= BUFQ_SORT_RAWBLOCK; 152 break; 153 default: 154 panic("bufq_alloc: sort out of range"); 155 } 156 157 /* 158 * select strategy. 159 * if a strategy specified by flags is found, use it. 160 * otherwise, select one with the largest bs_prio. 161 */ 162 mutex_enter(&bufq_mutex); 163 do { 164 gen = module_gen; 165 bsp = NULL; 166 found_exact = false; 167 168 SLIST_FOREACH(it, &bufq_strat_list, bs_next) { 169 if (strategy != BUFQ_STRAT_ANY && 170 STRAT_MATCH(strategy, (it))) { 171 bsp = it; 172 found_exact = true; 173 break; 174 } 175 if (bsp == NULL || (it)->bs_prio > bsp->bs_prio) 176 bsp = it; 177 } 178 if (strategy == BUFQ_STRAT_ANY || found_exact) 179 break; 180 181 /* Try to autoload device module */ 182 strlcpy(module_name, "bufq_", sizeof(module_name)); 183 strlcat(module_name, strategy, sizeof(module_name)); 184 mutex_exit(&bufq_mutex); 185 (void) module_autoload(module_name, MODULE_CLASS_MISC); 186 mutex_enter(&bufq_mutex); 187 } while (gen != module_gen); 188 189 if (bsp == NULL) { 190 panic("bufq_alloc: no strategy"); 191 } 192 if (strategy != BUFQ_STRAT_ANY && !found_exact) { 193 if ((flags & BUFQ_EXACT)) { 194 error = ENOENT; 195 mutex_exit(&bufq_mutex); 196 goto out; 197 } 198 #if defined(DEBUG) 199 printf("bufq_alloc: '%s' is not available. using '%s'.\n", 200 strategy, bsp->bs_name); 201 #endif 202 } 203 #if defined(BUFQ_DEBUG) 204 /* XXX aprint? */ 205 printf("bufq_alloc: using '%s'\n", bsp->bs_name); 206 #endif 207 208 bsp->bs_refcnt++; 209 mutex_exit(&bufq_mutex); 210 *bufqp = bufq = kmem_zalloc(sizeof(*bufq), KM_SLEEP); 211 bufq->bq_flags = flags; 212 bufq->bq_strat = bsp; 213 (*bsp->bs_initfn)(bufq); 214 215 out: 216 return error; 217 } 218 219 void 220 bufq_put(struct bufq_state *bufq, struct buf *bp) 221 { 222 223 (*bufq->bq_put)(bufq, bp); 224 } 225 226 struct buf * 227 bufq_get(struct bufq_state *bufq) 228 { 229 230 return (*bufq->bq_get)(bufq, 1); 231 } 232 233 struct buf * 234 bufq_peek(struct bufq_state *bufq) 235 { 236 237 return (*bufq->bq_get)(bufq, 0); 238 } 239 240 struct buf * 241 bufq_cancel(struct bufq_state *bufq, struct buf *bp) 242 { 243 244 return (*bufq->bq_cancel)(bufq, bp); 245 } 246 247 /* 248 * Drain a device buffer queue. 249 */ 250 void 251 bufq_drain(struct bufq_state *bufq) 252 { 253 struct buf *bp; 254 255 while ((bp = bufq_get(bufq)) != NULL) { 256 bp->b_error = EIO; 257 bp->b_resid = bp->b_bcount; 258 biodone(bp); 259 } 260 } 261 262 /* 263 * Destroy a device buffer queue. 264 */ 265 void 266 bufq_free(struct bufq_state *bufq) 267 { 268 269 KASSERT(bufq_peek(bufq) == NULL); 270 271 bufq->bq_fini(bufq); 272 273 mutex_enter(&bufq_mutex); 274 bufq->bq_strat->bs_refcnt--; 275 mutex_exit(&bufq_mutex); 276 277 kmem_free(bufq, sizeof(*bufq)); 278 } 279 280 /* 281 * get a strategy identifier of a buffer queue. 282 */ 283 const char * 284 bufq_getstrategyname(struct bufq_state *bufq) 285 { 286 287 return bufq->bq_strat->bs_name; 288 } 289 290 /* 291 * move all requests on a buffer queue to another. 292 */ 293 void 294 bufq_move(struct bufq_state *dst, struct bufq_state *src) 295 { 296 struct buf *bp; 297 298 while ((bp = bufq_get(src)) != NULL) { 299 bufq_put(dst, bp); 300 } 301 } 302 303 static int 304 docopy(char *buf, size_t *bufoffp, size_t buflen, 305 const char *datap, size_t datalen) 306 { 307 int error = 0; 308 309 if (buf != NULL && datalen > 0) { 310 311 if (*bufoffp + datalen > buflen) { 312 goto out; 313 } 314 error = copyout(datap, buf + *bufoffp, datalen); 315 if (error) { 316 goto out; 317 } 318 } 319 out: 320 if (error == 0) { 321 *bufoffp += datalen; 322 } 323 324 return error; 325 } 326 327 static int 328 docopystr(char *buf, size_t *bufoffp, size_t buflen, const char *datap) 329 { 330 331 return docopy(buf, bufoffp, buflen, datap, strlen(datap)); 332 } 333 334 static int 335 docopynul(char *buf, size_t *bufoffp, size_t buflen) 336 { 337 338 return docopy(buf, bufoffp, buflen, "", 1); 339 } 340 341 /* 342 * sysctl function that will print all bufq strategies 343 * currently available to the kernel. 344 */ 345 static int 346 sysctl_kern_bufq_strategies(SYSCTLFN_ARGS) 347 { 348 const struct bufq_strat *bq_strat; 349 const char *delim = ""; 350 size_t off = 0; 351 size_t buflen = *oldlenp; 352 int error; 353 354 SLIST_FOREACH(bq_strat, &bufq_strat_list, bs_next) { 355 error = docopystr(oldp, &off, buflen, delim); 356 if (error) { 357 goto out; 358 } 359 error = docopystr(oldp, &off, buflen, (bq_strat)->bs_name); 360 if (error) { 361 goto out; 362 } 363 delim = " "; 364 } 365 366 /* In case there are no registered strategies ... */ 367 if (off == 0) { 368 error = docopystr(oldp, &off, buflen, "NULL"); 369 if (error) { 370 goto out; 371 } 372 } 373 374 /* NUL terminate */ 375 error = docopynul(oldp, &off, buflen); 376 out: 377 *oldlenp = off; 378 return error; 379 } 380 381 static void 382 sysctl_kern_bufq_strategies_setup(struct sysctllog **clog) 383 { 384 const struct sysctlnode *node; 385 386 node = NULL; 387 sysctl_createv(clog, 0, NULL, &node, 388 CTLFLAG_PERMANENT, 389 CTLTYPE_NODE, "bufq", 390 SYSCTL_DESCR("buffer queue subtree"), 391 NULL, 0, NULL, 0, 392 CTL_KERN, CTL_CREATE, CTL_EOL); 393 if (node != NULL) { 394 sysctl_createv(clog, 0, NULL, NULL, 395 CTLFLAG_PERMANENT, 396 CTLTYPE_STRING, "strategies", 397 SYSCTL_DESCR("List of bufq strategies present"), 398 sysctl_kern_bufq_strategies, 0, NULL, 0, 399 CTL_KERN, node->sysctl_num, CTL_CREATE, CTL_EOL); 400 } 401 } 402
Indexes created Mon Sep 22 10:09:38 GMT 2025