subr_bufq.c revision 1.20.22.1
1 /* $NetBSD: subr_bufq.c,v 1.20.22.1 2014/08/20 00:04:29 tls 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 1.20.22.1 2014/08/20 00:04:29 tls 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 struct sysctllog *sysctllog; 90 static int 91 bufq_init(void) 92 { 93 94 sysctl_kern_bufq_strategies_setup(&sysctllog); 95 return 0; 96 } 97 98 /* 99 * Create a device buffer queue. 100 */ 101 int 102 bufq_alloc(struct bufq_state **bufqp, const char *strategy, int flags) 103 { 104 __link_set_decl(bufq_strats, const struct bufq_strat); 105 const struct bufq_strat *bsp; 106 const struct bufq_strat * const *it; 107 struct bufq_state *bufq; 108 static ONCE_DECL(bufq_init_ctrl); 109 int error = 0; 110 111 RUN_ONCE(&bufq_init_ctrl, bufq_init); 112 113 KASSERT((flags & BUFQ_EXACT) == 0 || strategy != BUFQ_STRAT_ANY); 114 115 switch (flags & BUFQ_SORT_MASK) { 116 case BUFQ_SORT_RAWBLOCK: 117 case BUFQ_SORT_CYLINDER: 118 break; 119 case 0: 120 /* 121 * for strategies which don't care about block numbers. 122 * eg. fcfs 123 */ 124 flags |= BUFQ_SORT_RAWBLOCK; 125 break; 126 default: 127 panic("bufq_alloc: sort out of range"); 128 } 129 130 /* 131 * select strategy. 132 * if a strategy specified by flags is found, use it. 133 * otherwise, select one with the largest bs_prio. 134 */ 135 bsp = NULL; 136 __link_set_foreach(it, bufq_strats) { 137 if ((*it) == &bufq_strat_dummy) 138 continue; 139 if (strategy != BUFQ_STRAT_ANY && 140 STRAT_MATCH(strategy, (*it))) { 141 bsp = *it; 142 break; 143 } 144 if (bsp == NULL || (*it)->bs_prio > bsp->bs_prio) 145 bsp = *it; 146 } 147 148 if (bsp == NULL) { 149 panic("bufq_alloc: no strategy"); 150 } 151 if (strategy != BUFQ_STRAT_ANY && !STRAT_MATCH(strategy, bsp)) { 152 if ((flags & BUFQ_EXACT)) { 153 error = ENOENT; 154 goto out; 155 } 156 #if defined(DEBUG) 157 printf("bufq_alloc: '%s' is not available. using '%s'.\n", 158 strategy, bsp->bs_name); 159 #endif 160 } 161 #if defined(BUFQ_DEBUG) 162 /* XXX aprint? */ 163 printf("bufq_alloc: using '%s'\n", bsp->bs_name); 164 #endif 165 166 *bufqp = bufq = kmem_zalloc(sizeof(*bufq), KM_SLEEP); 167 bufq->bq_flags = flags; 168 bufq->bq_strat = bsp; 169 (*bsp->bs_initfn)(bufq); 170 171 out: 172 return error; 173 } 174 175 void 176 bufq_put(struct bufq_state *bufq, struct buf *bp) 177 { 178 179 (*bufq->bq_put)(bufq, bp); 180 } 181 182 struct buf * 183 bufq_get(struct bufq_state *bufq) 184 { 185 186 return (*bufq->bq_get)(bufq, 1); 187 } 188 189 struct buf * 190 bufq_peek(struct bufq_state *bufq) 191 { 192 193 return (*bufq->bq_get)(bufq, 0); 194 } 195 196 struct buf * 197 bufq_cancel(struct bufq_state *bufq, struct buf *bp) 198 { 199 200 return (*bufq->bq_cancel)(bufq, bp); 201 } 202 203 /* 204 * Drain a device buffer queue. 205 */ 206 void 207 bufq_drain(struct bufq_state *bufq) 208 { 209 struct buf *bp; 210 211 while ((bp = bufq_get(bufq)) != NULL) { 212 bp->b_error = EIO; 213 bp->b_resid = bp->b_bcount; 214 biodone(bp); 215 } 216 } 217 218 /* 219 * Destroy a device buffer queue. 220 */ 221 void 222 bufq_free(struct bufq_state *bufq) 223 { 224 225 KASSERT(bufq_peek(bufq) == NULL); 226 227 bufq->bq_fini(bufq); 228 kmem_free(bufq, sizeof(*bufq)); 229 } 230 231 /* 232 * get a strategy identifier of a buffer queue. 233 */ 234 const char * 235 bufq_getstrategyname(struct bufq_state *bufq) 236 { 237 238 return bufq->bq_strat->bs_name; 239 } 240 241 /* 242 * move all requests on a buffer queue to another. 243 */ 244 void 245 bufq_move(struct bufq_state *dst, struct bufq_state *src) 246 { 247 struct buf *bp; 248 249 while ((bp = bufq_get(src)) != NULL) { 250 bufq_put(dst, bp); 251 } 252 } 253 254 static int 255 docopy(char *buf, size_t *bufoffp, size_t buflen, 256 const char *datap, size_t datalen) 257 { 258 int error = 0; 259 260 if (buf != NULL && datalen > 0) { 261 262 if (*bufoffp + datalen > buflen) { 263 goto out; 264 } 265 error = copyout(datap, buf + *bufoffp, datalen); 266 if (error) { 267 goto out; 268 } 269 } 270 out: 271 if (error == 0) { 272 *bufoffp += datalen; 273 } 274 275 return error; 276 } 277 278 static int 279 docopystr(char *buf, size_t *bufoffp, size_t buflen, const char *datap) 280 { 281 282 return docopy(buf, bufoffp, buflen, datap, strlen(datap)); 283 } 284 285 static int 286 docopynul(char *buf, size_t *bufoffp, size_t buflen) 287 { 288 289 return docopy(buf, bufoffp, buflen, "", 1); 290 } 291 292 /* 293 * sysctl function that will print all bufq strategies 294 * built in the kernel. 295 */ 296 static int 297 sysctl_kern_bufq_strategies(SYSCTLFN_ARGS) 298 { 299 __link_set_decl(bufq_strats, const struct bufq_strat); 300 const struct bufq_strat * const *bq_strat; 301 const char *delim = ""; 302 size_t off = 0; 303 size_t buflen = *oldlenp; 304 int error; 305 306 __link_set_foreach(bq_strat, bufq_strats) { 307 if ((*bq_strat) == &bufq_strat_dummy) { 308 continue; 309 } 310 error = docopystr(oldp, &off, buflen, delim); 311 if (error) { 312 goto out; 313 } 314 error = docopystr(oldp, &off, buflen, (*bq_strat)->bs_name); 315 if (error) { 316 goto out; 317 } 318 delim = " "; 319 } 320 321 /* NUL terminate */ 322 error = docopynul(oldp, &off, buflen); 323 out: 324 *oldlenp = off; 325 return error; 326 } 327 328 static void 329 sysctl_kern_bufq_strategies_setup(struct sysctllog **clog) 330 { 331 const struct sysctlnode *node; 332 333 node = NULL; 334 sysctl_createv(clog, 0, NULL, &node, 335 CTLFLAG_PERMANENT, 336 CTLTYPE_NODE, "bufq", 337 SYSCTL_DESCR("buffer queue subtree"), 338 NULL, 0, NULL, 0, 339 CTL_KERN, CTL_CREATE, CTL_EOL); 340 if (node != NULL) { 341 sysctl_createv(clog, 0, NULL, NULL, 342 CTLFLAG_PERMANENT, 343 CTLTYPE_STRING, "strategies", 344 SYSCTL_DESCR("List of bufq strategies present"), 345 sysctl_kern_bufq_strategies, 0, NULL, 0, 346 CTL_KERN, node->sysctl_num, CTL_CREATE, CTL_EOL); 347 } 348 } 349
Indexes created Mon Sep 29 21:09:56 GMT 2025