subr_bufq.c revision 1.15.8.1
1 /* $NetBSD: subr_bufq.c,v 1.15.8.1 2009/01/19 13:19:39 skrll 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 1.15.8.1 2009/01/19 13:19:39 skrll 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 struct buf * 181 bufq_cancel(struct bufq_state *bufq, struct buf *bp) 182 { 183 184 return (*bufq->bq_cancel)(bufq, bp); 185 } 186 187 /* 188 * Drain a device buffer queue. 189 */ 190 void 191 bufq_drain(struct bufq_state *bufq) 192 { 193 struct buf *bp; 194 195 while ((bp = bufq_get(bufq)) != NULL) { 196 bp->b_error = EIO; 197 bp->b_resid = bp->b_bcount; 198 biodone(bp); 199 } 200 } 201 202 /* 203 * Destroy a device buffer queue. 204 */ 205 void 206 bufq_free(struct bufq_state *bufq) 207 { 208 209 KASSERT(bufq->bq_private != NULL); 210 KASSERT(bufq_peek(bufq) == NULL); 211 212 free(bufq->bq_private, M_DEVBUF); 213 free(bufq, M_DEVBUF); 214 } 215 216 /* 217 * get a strategy identifier of a buffer queue. 218 */ 219 const char * 220 bufq_getstrategyname(struct bufq_state *bufq) 221 { 222 223 return bufq->bq_strat->bs_name; 224 } 225 226 /* 227 * move all requests on a buffer queue to another. 228 */ 229 void 230 bufq_move(struct bufq_state *dst, struct bufq_state *src) 231 { 232 struct buf *bp; 233 234 while ((bp = bufq_get(src)) != NULL) { 235 bufq_put(dst, bp); 236 } 237 } 238 239 static int 240 docopy(char *buf, size_t *bufoffp, size_t buflen, 241 const char *datap, size_t datalen) 242 { 243 int error = 0; 244 245 if (buf != NULL && datalen > 0) { 246 247 if (*bufoffp + datalen > buflen) { 248 goto out; 249 } 250 error = copyout(datap, buf + *bufoffp, datalen); 251 if (error) { 252 goto out; 253 } 254 } 255 out: 256 if (error == 0) { 257 *bufoffp += datalen; 258 } 259 260 return error; 261 } 262 263 static int 264 docopystr(char *buf, size_t *bufoffp, size_t buflen, const char *datap) 265 { 266 267 return docopy(buf, bufoffp, buflen, datap, strlen(datap)); 268 } 269 270 static int 271 docopynul(char *buf, size_t *bufoffp, size_t buflen) 272 { 273 274 return docopy(buf, bufoffp, buflen, "", 1); 275 } 276 277 /* 278 * sysctl function that will print all bufq strategies 279 * built in the kernel. 280 */ 281 static int 282 sysctl_kern_bufq_strategies(SYSCTLFN_ARGS) 283 { 284 __link_set_decl(bufq_strats, const struct bufq_strat); 285 const struct bufq_strat * const *bq_strat; 286 const char *delim = ""; 287 size_t off = 0; 288 size_t buflen = *oldlenp; 289 int error; 290 291 __link_set_foreach(bq_strat, bufq_strats) { 292 if ((*bq_strat) == &bufq_strat_dummy) { 293 continue; 294 } 295 error = docopystr(oldp, &off, buflen, delim); 296 if (error) { 297 goto out; 298 } 299 error = docopystr(oldp, &off, buflen, (*bq_strat)->bs_name); 300 if (error) { 301 goto out; 302 } 303 delim = " "; 304 } 305 306 /* NUL terminate */ 307 error = docopynul(oldp, &off, buflen); 308 out: 309 *oldlenp = off; 310 return error; 311 } 312 313 SYSCTL_SETUP(sysctl_kern_bufq_strategies_setup, "sysctl kern.bufq tree setup") 314 { 315 const struct sysctlnode *node; 316 317 sysctl_createv(clog, 0, NULL, NULL, 318 CTLFLAG_PERMANENT, 319 CTLTYPE_NODE, "kern", NULL, 320 NULL, 0, NULL, 0, 321 CTL_KERN, CTL_EOL); 322 node = NULL; 323 sysctl_createv(clog, 0, NULL, &node, 324 CTLFLAG_PERMANENT, 325 CTLTYPE_NODE, "bufq", 326 SYSCTL_DESCR("buffer queue subtree"), 327 NULL, 0, NULL, 0, 328 CTL_KERN, CTL_CREATE, CTL_EOL); 329 if (node != NULL) { 330 sysctl_createv(clog, 0, NULL, NULL, 331 CTLFLAG_PERMANENT, 332 CTLTYPE_STRING, "strategies", 333 SYSCTL_DESCR("List of bufq strategies present"), 334 sysctl_kern_bufq_strategies, 0, NULL, 0, 335 CTL_KERN, node->sysctl_num, CTL_CREATE, CTL_EOL); 336 } 337 } 338
Indexes created Mon Sep 29 21:09:56 GMT 2025