subr_bufq.c revision 1.19
1 /* $NetBSD: subr_bufq.c,v 1.19 2009/09/16 15:23:04 pooka 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 1.19 2009/09/16 15:23:04 pooka 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/once.h> 80 #include <sys/sysctl.h> 81 82 BUFQ_DEFINE(dummy, 0, NULL); /* so that bufq_strats won't be empty */ 83 84 #define STRAT_MATCH(id, bs) (strcmp((id), (bs)->bs_name) == 0) 85 86 static int bufq_init(void); 87 static void sysctl_kern_bufq_strategies_setup(struct sysctllog **); 88 89 static int 90 bufq_init(void) 91 { 92 93 sysctl_kern_bufq_strategies_setup(NULL); 94 return 0; 95 } 96 97 /* 98 * Create a device buffer queue. 99 */ 100 int 101 bufq_alloc(struct bufq_state **bufqp, const char *strategy, int flags) 102 { 103 __link_set_decl(bufq_strats, const struct bufq_strat); 104 const struct bufq_strat *bsp; 105 const struct bufq_strat * const *it; 106 struct bufq_state *bufq; 107 static ONCE_DECL(bufq_init_ctrl); 108 int error = 0; 109 110 RUN_ONCE(&bufq_init_ctrl, bufq_init); 111 112 KASSERT((flags & BUFQ_EXACT) == 0 || strategy != BUFQ_STRAT_ANY); 113 114 switch (flags & BUFQ_SORT_MASK) { 115 case BUFQ_SORT_RAWBLOCK: 116 case BUFQ_SORT_CYLINDER: 117 break; 118 case 0: 119 /* 120 * for strategies which don't care about block numbers. 121 * eg. fcfs 122 */ 123 flags |= BUFQ_SORT_RAWBLOCK; 124 break; 125 default: 126 panic("bufq_alloc: sort out of range"); 127 } 128 129 /* 130 * select strategy. 131 * if a strategy specified by flags is found, use it. 132 * otherwise, select one with the largest bs_prio. 133 */ 134 bsp = NULL; 135 __link_set_foreach(it, bufq_strats) { 136 if ((*it) == &bufq_strat_dummy) 137 continue; 138 if (strategy != BUFQ_STRAT_ANY && 139 STRAT_MATCH(strategy, (*it))) { 140 bsp = *it; 141 break; 142 } 143 if (bsp == NULL || (*it)->bs_prio > bsp->bs_prio) 144 bsp = *it; 145 } 146 147 if (bsp == NULL) { 148 panic("bufq_alloc: no strategy"); 149 } 150 if (strategy != BUFQ_STRAT_ANY && !STRAT_MATCH(strategy, bsp)) { 151 if ((flags & BUFQ_EXACT)) { 152 error = ENOENT; 153 goto out; 154 } 155 #if defined(DEBUG) 156 printf("bufq_alloc: '%s' is not available. using '%s'.\n", 157 strategy, bsp->bs_name); 158 #endif 159 } 160 #if defined(BUFQ_DEBUG) 161 /* XXX aprint? */ 162 printf("bufq_alloc: using '%s'\n", bsp->bs_name); 163 #endif 164 165 *bufqp = bufq = kmem_zalloc(sizeof(*bufq), KM_SLEEP); 166 bufq->bq_flags = flags; 167 bufq->bq_strat = bsp; 168 (*bsp->bs_initfn)(bufq); 169 170 out: 171 return error; 172 } 173 174 void 175 bufq_put(struct bufq_state *bufq, struct buf *bp) 176 { 177 178 (*bufq->bq_put)(bufq, bp); 179 } 180 181 struct buf * 182 bufq_get(struct bufq_state *bufq) 183 { 184 185 return (*bufq->bq_get)(bufq, 1); 186 } 187 188 struct buf * 189 bufq_peek(struct bufq_state *bufq) 190 { 191 192 return (*bufq->bq_get)(bufq, 0); 193 } 194 195 struct buf * 196 bufq_cancel(struct bufq_state *bufq, struct buf *bp) 197 { 198 199 return (*bufq->bq_cancel)(bufq, bp); 200 } 201 202 /* 203 * Drain a device buffer queue. 204 */ 205 void 206 bufq_drain(struct bufq_state *bufq) 207 { 208 struct buf *bp; 209 210 while ((bp = bufq_get(bufq)) != NULL) { 211 bp->b_error = EIO; 212 bp->b_resid = bp->b_bcount; 213 biodone(bp); 214 } 215 } 216 217 /* 218 * Destroy a device buffer queue. 219 */ 220 void 221 bufq_free(struct bufq_state *bufq) 222 { 223 224 KASSERT(bufq_peek(bufq) == NULL); 225 226 bufq->bq_fini(bufq); 227 kmem_free(bufq, sizeof(*bufq)); 228 } 229 230 /* 231 * get a strategy identifier of a buffer queue. 232 */ 233 const char * 234 bufq_getstrategyname(struct bufq_state *bufq) 235 { 236 237 return bufq->bq_strat->bs_name; 238 } 239 240 /* 241 * move all requests on a buffer queue to another. 242 */ 243 void 244 bufq_move(struct bufq_state *dst, struct bufq_state *src) 245 { 246 struct buf *bp; 247 248 while ((bp = bufq_get(src)) != NULL) { 249 bufq_put(dst, bp); 250 } 251 } 252 253 static int 254 docopy(char *buf, size_t *bufoffp, size_t buflen, 255 const char *datap, size_t datalen) 256 { 257 int error = 0; 258 259 if (buf != NULL && datalen > 0) { 260 261 if (*bufoffp + datalen > buflen) { 262 goto out; 263 } 264 error = copyout(datap, buf + *bufoffp, datalen); 265 if (error) { 266 goto out; 267 } 268 } 269 out: 270 if (error == 0) { 271 *bufoffp += datalen; 272 } 273 274 return error; 275 } 276 277 static int 278 docopystr(char *buf, size_t *bufoffp, size_t buflen, const char *datap) 279 { 280 281 return docopy(buf, bufoffp, buflen, datap, strlen(datap)); 282 } 283 284 static int 285 docopynul(char *buf, size_t *bufoffp, size_t buflen) 286 { 287 288 return docopy(buf, bufoffp, buflen, "", 1); 289 } 290 291 /* 292 * sysctl function that will print all bufq strategies 293 * built in the kernel. 294 */ 295 static int 296 sysctl_kern_bufq_strategies(SYSCTLFN_ARGS) 297 { 298 __link_set_decl(bufq_strats, const struct bufq_strat); 299 const struct bufq_strat * const *bq_strat; 300 const char *delim = ""; 301 size_t off = 0; 302 size_t buflen = *oldlenp; 303 int error; 304 305 __link_set_foreach(bq_strat, bufq_strats) { 306 if ((*bq_strat) == &bufq_strat_dummy) { 307 continue; 308 } 309 error = docopystr(oldp, &off, buflen, delim); 310 if (error) { 311 goto out; 312 } 313 error = docopystr(oldp, &off, buflen, (*bq_strat)->bs_name); 314 if (error) { 315 goto out; 316 } 317 delim = " "; 318 } 319 320 /* NUL terminate */ 321 error = docopynul(oldp, &off, buflen); 322 out: 323 *oldlenp = off; 324 return error; 325 } 326 327 static void 328 sysctl_kern_bufq_strategies_setup(struct sysctllog **clog) 329 { 330 const struct sysctlnode *node; 331 332 sysctl_createv(clog, 0, NULL, NULL, 333 CTLFLAG_PERMANENT, 334 CTLTYPE_NODE, "kern", NULL, 335 NULL, 0, NULL, 0, 336 CTL_KERN, CTL_EOL); 337 node = NULL; 338 sysctl_createv(clog, 0, NULL, &node, 339 CTLFLAG_PERMANENT, 340 CTLTYPE_NODE, "bufq", 341 SYSCTL_DESCR("buffer queue subtree"), 342 NULL, 0, NULL, 0, 343 CTL_KERN, CTL_CREATE, CTL_EOL); 344 if (node != NULL) { 345 sysctl_createv(clog, 0, NULL, NULL, 346 CTLFLAG_PERMANENT, 347 CTLTYPE_STRING, "strategies", 348 SYSCTL_DESCR("List of bufq strategies present"), 349 sysctl_kern_bufq_strategies, 0, NULL, 0, 350 CTL_KERN, node->sysctl_num, CTL_CREATE, CTL_EOL); 351 } 352 } 353
Indexes created Mon Sep 29 21:09:56 GMT 2025