subr_bufq.c revision 1.14
1 /* $NetBSD: subr_bufq.c,v 1.14 2008/04/28 20:24:04 martin 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 1.14 2008/04/28 20:24:04 martin 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/malloc.h> 79 #include <sys/sysctl.h> 80 81 BUFQ_DEFINE(dummy, 0, NULL); /* so that bufq_strats won't be empty */ 82 83 #define STRAT_MATCH(id, bs) (strcmp((id), (bs)->bs_name) == 0) 84 85 /* 86 * Create a device buffer queue. 87 */ 88 int 89 bufq_alloc(struct bufq_state **bufqp, const char *strategy, int flags) 90 { 91 __link_set_decl(bufq_strats, const struct bufq_strat); 92 const struct bufq_strat *bsp; 93 const struct bufq_strat * const *it; 94 struct bufq_state *bufq; 95 int error = 0; 96 97 KASSERT((flags & BUFQ_EXACT) == 0 || strategy != BUFQ_STRAT_ANY); 98 99 switch (flags & BUFQ_SORT_MASK) { 100 case BUFQ_SORT_RAWBLOCK: 101 case BUFQ_SORT_CYLINDER: 102 break; 103 case 0: 104 /* 105 * for strategies which don't care about block numbers. 106 * eg. fcfs 107 */ 108 flags |= BUFQ_SORT_RAWBLOCK; 109 break; 110 default: 111 panic("bufq_alloc: sort out of range"); 112 } 113 114 /* 115 * select strategy. 116 * if a strategy specified by flags is found, use it. 117 * otherwise, select one with the largest bs_prio. 118 */ 119 bsp = NULL; 120 __link_set_foreach(it, bufq_strats) { 121 if ((*it) == &bufq_strat_dummy) 122 continue; 123 if (strategy != BUFQ_STRAT_ANY && 124 STRAT_MATCH(strategy, (*it))) { 125 bsp = *it; 126 break; 127 } 128 if (bsp == NULL || (*it)->bs_prio > bsp->bs_prio) 129 bsp = *it; 130 } 131 132 if (bsp == NULL) { 133 panic("bufq_alloc: no strategy"); 134 } 135 if (strategy != BUFQ_STRAT_ANY && !STRAT_MATCH(strategy, bsp)) { 136 if ((flags & BUFQ_EXACT)) { 137 error = ENOENT; 138 goto out; 139 } 140 #if defined(DEBUG) 141 printf("bufq_alloc: '%s' is not available. using '%s'.\n", 142 strategy, bsp->bs_name); 143 #endif 144 } 145 #if defined(BUFQ_DEBUG) 146 /* XXX aprint? */ 147 printf("bufq_alloc: using '%s'\n", bsp->bs_name); 148 #endif 149 150 *bufqp = bufq = malloc(sizeof(*bufq), M_DEVBUF, M_WAITOK | M_ZERO); 151 bufq->bq_flags = flags; 152 bufq->bq_strat = bsp; 153 (*bsp->bs_initfn)(bufq); 154 155 out: 156 return error; 157 } 158 159 void 160 bufq_put(struct bufq_state *bufq, struct buf *bp) 161 { 162 163 (*bufq->bq_put)(bufq, bp); 164 } 165 166 struct buf * 167 bufq_get(struct bufq_state *bufq) 168 { 169 170 return (*bufq->bq_get)(bufq, 1); 171 } 172 173 struct buf * 174 bufq_peek(struct bufq_state *bufq) 175 { 176 177 return (*bufq->bq_get)(bufq, 0); 178 } 179 180 /* 181 * Drain a device buffer queue. 182 */ 183 void 184 bufq_drain(struct bufq_state *bufq) 185 { 186 struct buf *bp; 187 188 while ((bp = BUFQ_GET(bufq)) != NULL) { 189 bp->b_error = EIO; 190 bp->b_resid = bp->b_bcount; 191 biodone(bp); 192 } 193 } 194 195 /* 196 * Destroy a device buffer queue. 197 */ 198 void 199 bufq_free(struct bufq_state *bufq) 200 { 201 202 KASSERT(bufq->bq_private != NULL); 203 KASSERT(BUFQ_PEEK(bufq) == NULL); 204 205 free(bufq->bq_private, M_DEVBUF); 206 free(bufq, M_DEVBUF); 207 } 208 209 /* 210 * get a strategy identifier of a buffer queue. 211 */ 212 const char * 213 bufq_getstrategyname(struct bufq_state *bufq) 214 { 215 216 return bufq->bq_strat->bs_name; 217 } 218 219 /* 220 * move all requests on a buffer queue to another. 221 */ 222 void 223 bufq_move(struct bufq_state *dst, struct bufq_state *src) 224 { 225 struct buf *bp; 226 227 while ((bp = BUFQ_GET(src)) != NULL) { 228 BUFQ_PUT(dst, bp); 229 } 230 } 231 232 static int 233 docopy(char *buf, size_t *bufoffp, size_t buflen, 234 const char *datap, size_t datalen) 235 { 236 int error = 0; 237 238 if (buf != NULL && datalen > 0) { 239 240 if (*bufoffp + datalen > buflen) { 241 goto out; 242 } 243 error = copyout(datap, buf + *bufoffp, datalen); 244 if (error) { 245 goto out; 246 } 247 } 248 out: 249 if (error == 0) { 250 *bufoffp += datalen; 251 } 252 253 return error; 254 } 255 256 static int 257 docopystr(char *buf, size_t *bufoffp, size_t buflen, const char *datap) 258 { 259 260 return docopy(buf, bufoffp, buflen, datap, strlen(datap)); 261 } 262 263 static int 264 docopynul(char *buf, size_t *bufoffp, size_t buflen) 265 { 266 267 return docopy(buf, bufoffp, buflen, "", 1); 268 } 269 270 /* 271 * sysctl function that will print all bufq strategies 272 * built in the kernel. 273 */ 274 static int 275 sysctl_kern_bufq_strategies(SYSCTLFN_ARGS) 276 { 277 __link_set_decl(bufq_strats, const struct bufq_strat); 278 const struct bufq_strat * const *bq_strat; 279 const char *delim = ""; 280 size_t off = 0; 281 size_t buflen = *oldlenp; 282 int error; 283 284 __link_set_foreach(bq_strat, bufq_strats) { 285 if ((*bq_strat) == &bufq_strat_dummy) { 286 continue; 287 } 288 error = docopystr(oldp, &off, buflen, delim); 289 if (error) { 290 goto out; 291 } 292 error = docopystr(oldp, &off, buflen, (*bq_strat)->bs_name); 293 if (error) { 294 goto out; 295 } 296 delim = " "; 297 } 298 299 /* NUL terminate */ 300 error = docopynul(oldp, &off, buflen); 301 out: 302 *oldlenp = off; 303 return error; 304 } 305 306 SYSCTL_SETUP(sysctl_kern_bufq_strategies_setup, "sysctl kern.bufq tree setup") 307 { 308 const struct sysctlnode *node; 309 310 sysctl_createv(clog, 0, NULL, NULL, 311 CTLFLAG_PERMANENT, 312 CTLTYPE_NODE, "kern", NULL, 313 NULL, 0, NULL, 0, 314 CTL_KERN, CTL_EOL); 315 node = NULL; 316 sysctl_createv(clog, 0, NULL, &node, 317 CTLFLAG_PERMANENT, 318 CTLTYPE_NODE, "bufq", 319 SYSCTL_DESCR("buffer queue subtree"), 320 NULL, 0, NULL, 0, 321 CTL_KERN, CTL_CREATE, CTL_EOL); 322 if (node != NULL) { 323 sysctl_createv(clog, 0, NULL, NULL, 324 CTLFLAG_PERMANENT, 325 CTLTYPE_STRING, "strategies", 326 SYSCTL_DESCR("List of bufq strategies present"), 327 sysctl_kern_bufq_strategies, 0, NULL, 0, 328 CTL_KERN, node->sysctl_num, CTL_CREATE, CTL_EOL); 329 } 330 } 331
Indexes created Mon Sep 29 21:09:56 GMT 2025