subr_bufq.c revision 1.5
1 /* $NetBSD: subr_bufq.c,v 1.5 2005/10/16 02:02:23 yamt 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 * 3. All advertising materials mentioning features or use of this software 21 * must display the following acknowledgement: 22 * This product includes software developed by the NetBSD 23 * Foundation, Inc. and its contributors. 24 * 4. Neither the name of The NetBSD Foundation nor the names of its 25 * contributors may be used to endorse or promote products derived 26 * from this software without specific prior written permission. 27 * 28 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 29 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 30 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 31 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 32 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 33 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 34 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 35 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 36 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 37 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 38 * POSSIBILITY OF SUCH DAMAGE. 39 */ 40 41 /* 42 * Copyright (c) 1982, 1986, 1988, 1993 43 * The Regents of the University of California. All rights reserved. 44 * (c) UNIX System Laboratories, Inc. 45 * All or some portions of this file are derived from material licensed 46 * to the University of California by American Telephone and Telegraph 47 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 48 * the permission of UNIX System Laboratories, Inc. 49 * 50 * Redistribution and use in source and binary forms, with or without 51 * modification, are permitted provided that the following conditions 52 * are met: 53 * 1. Redistributions of source code must retain the above copyright 54 * notice, this list of conditions and the following disclaimer. 55 * 2. Redistributions in binary form must reproduce the above copyright 56 * notice, this list of conditions and the following disclaimer in the 57 * documentation and/or other materials provided with the distribution. 58 * 3. Neither the name of the University nor the names of its contributors 59 * may be used to endorse or promote products derived from this software 60 * without specific prior written permission. 61 * 62 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 63 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 64 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 65 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 66 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 67 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 68 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 69 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 70 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 71 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 72 * SUCH DAMAGE. 73 * 74 * @(#)ufs_disksubr.c 8.5 (Berkeley) 1/21/94 75 */ 76 77 #include <sys/cdefs.h> 78 __KERNEL_RCSID(0, "$NetBSD: subr_bufq.c,v 1.5 2005/10/16 02:02:23 yamt Exp $"); 79 80 #include <sys/param.h> 81 #include <sys/systm.h> 82 #include <sys/buf.h> 83 #include <sys/bufq.h> 84 #include <sys/bufq_impl.h> 85 #include <sys/malloc.h> 86 #include <sys/sysctl.h> 87 88 BUFQ_DEFINE(dummy, 0, NULL); /* so that bufq_strats won't be empty */ 89 90 #define STRAT_MAX_NAME 32 91 #define STRAT_MATCH(id, bs) \ 92 ((id) == BUFQ_STRAT_ANY || strcmp((id), (bs)->bs_name) == 0) 93 94 /* 95 * Create a device buffer queue. 96 */ 97 int 98 bufq_alloc(struct bufq_state **bufqp, const char *strategy, int flags) 99 { 100 __link_set_decl(bufq_strats, const struct bufq_strat); 101 const struct bufq_strat *bsp; 102 const struct bufq_strat * const *it; 103 struct bufq_state *bufq; 104 int error = 0; 105 106 KASSERT((flags & BUFQ_EXACT) == 0 || strategy != BUFQ_STRAT_ANY); 107 108 switch (flags & BUFQ_SORT_MASK) { 109 case BUFQ_SORT_RAWBLOCK: 110 case BUFQ_SORT_CYLINDER: 111 break; 112 case 0: 113 /* 114 * for strategies which don't care about block numbers. 115 * eg. fcfs 116 */ 117 flags |= BUFQ_SORT_RAWBLOCK; 118 break; 119 default: 120 panic("bufq_alloc: sort out of range"); 121 } 122 123 /* 124 * select strategy. 125 * if a strategy specified by flags is found, use it. 126 * otherwise, select one with the largest bs_prio. 127 */ 128 bsp = NULL; 129 __link_set_foreach(it, bufq_strats) { 130 if ((*it) == &bufq_strat_dummy) 131 continue; 132 if (STRAT_MATCH(strategy, (*it))) { 133 bsp = *it; 134 break; 135 } 136 if (bsp == NULL || (*it)->bs_prio > bsp->bs_prio) 137 bsp = *it; 138 } 139 140 if (bsp == NULL) { 141 panic("bufq_alloc: no strategy"); 142 } 143 if (!STRAT_MATCH(strategy, bsp)) { 144 if ((flags & BUFQ_EXACT)) { 145 error = ENOENT; 146 goto out; 147 } 148 #if defined(DEBUG) 149 printf("bufq_alloc: '%s' is not available. using '%s'.\n", 150 strategy, bsp->bs_name); 151 #endif 152 } 153 #if defined(BUFQ_DEBUG) 154 /* XXX aprint? */ 155 printf("bufq_alloc: using '%s'\n", bsp->bs_name); 156 #endif 157 158 *bufqp = bufq = malloc(sizeof(*bufq), M_DEVBUF, M_WAITOK | M_ZERO); 159 bufq->bq_flags = flags; 160 bufq->bq_strat = bsp; 161 (*bsp->bs_initfn)(bufq); 162 163 out: 164 return 0; 165 } 166 167 void 168 bufq_put(struct bufq_state *bufq, struct buf *bp) 169 { 170 171 (*bufq->bq_put)(bufq, bp); 172 } 173 174 struct buf * 175 bufq_get(struct bufq_state *bufq) 176 { 177 178 return (*bufq->bq_get)(bufq, 1); 179 } 180 181 struct buf * 182 bufq_peek(struct bufq_state *bufq) 183 { 184 185 return (*bufq->bq_get)(bufq, 0); 186 } 187 188 /* 189 * Drain a device buffer queue. 190 */ 191 void 192 bufq_drain(struct bufq_state *bufq) 193 { 194 struct buf *bp; 195 196 while ((bp = BUFQ_GET(bufq)) != NULL) { 197 bp->b_error = EIO; 198 bp->b_flags |= B_ERROR; 199 bp->b_resid = bp->b_bcount; 200 biodone(bp); 201 } 202 } 203 204 /* 205 * Destroy a device buffer queue. 206 */ 207 void 208 bufq_free(struct bufq_state *bufq) 209 { 210 211 KASSERT(bufq->bq_private != NULL); 212 KASSERT(BUFQ_PEEK(bufq) == NULL); 213 214 free(bufq->bq_private, M_DEVBUF); 215 free(bufq, M_DEVBUF); 216 } 217 218 #if 0 219 /* 220 * get a strategy identifier of a buffer queue. 221 */ 222 const char * 223 bufq_getstrategyname(struct bufq_state *bufq) 224 { 225 226 return bufq->bq_strat->bs_name; 227 } 228 229 /* 230 * move all requests on a buffer queue to another. 231 */ 232 void 233 bufq_move(struct bufq_state *dst, struct bufq_state *src) 234 { 235 struct buf *bp; 236 237 while ((bp = BUFQ_GET(src)) != NULL) { 238 BUFQ_PUT(dst, bp); 239 } 240 } 241 #endif 242 243 /* 244 * sysctl function that will print all bufq strategies 245 * built in the kernel. 246 */ 247 static int 248 sysctl_kern_bufq_strategies(SYSCTLFN_ARGS) 249 { 250 __link_set_decl(bufq_strats, const struct bufq_strat); 251 const struct bufq_strat * const *bq_strat; 252 const char *strat; 253 char bf[STRAT_MAX_NAME]; 254 char *where = oldp; 255 size_t needed, left, slen; 256 int error, first; 257 258 first = 1; 259 error = needed = 0; 260 left = *oldlenp; 261 strat = NULL; 262 263 __link_set_foreach(bq_strat, bufq_strats) { 264 strat = (*bq_strat)->bs_name; 265 if (strat != NULL && 266 strncmp(strat, "dummy", sizeof(strat)) != 0) { 267 /* 268 * The following code comes from 269 * sysctl_vfs_generic_fstypes() (vfs_subr.c). 270 */ 271 if (where == NULL) 272 needed += strlen(strat) + 1; 273 else { 274 memset(bf, 0, sizeof(bf)); 275 if (first) { 276 strncpy(bf, strat, sizeof(bf)); 277 first = 0; 278 } else { 279 bf[0] = ' '; 280 strncpy(bf + 1, strat, sizeof(bf) - 1); 281 } 282 bf[sizeof(bf)-1] = '\0'; 283 slen = strlen(bf); 284 if (left < slen + 1) 285 break; 286 /* +1 to copy out the trailing NUL byte */ 287 error = copyout(bf, where, slen + 1); 288 if (error) 289 break; 290 where += slen; 291 needed += slen; 292 left -= slen; 293 } 294 } 295 } 296 *oldlenp = needed; 297 return error; 298 } 299 300 SYSCTL_SETUP(sysctl_kern_bufq_strategies_setup, "sysctl kern.bufq tree setup") 301 { 302 const struct sysctlnode *node; 303 304 sysctl_createv(clog, 0, NULL, NULL, 305 CTLFLAG_PERMANENT, 306 CTLTYPE_NODE, "kern", NULL, 307 NULL, 0, NULL, 0, 308 CTL_KERN, CTL_EOL); 309 node = NULL; 310 sysctl_createv(clog, 0, NULL, &node, 311 CTLFLAG_PERMANENT, 312 CTLTYPE_NODE, "bufq", 313 SYSCTL_DESCR("buffer queue subtree"), 314 NULL, 0, NULL, 0, 315 CTL_KERN, CTL_CREATE, CTL_EOL); 316 if (node != NULL) { 317 sysctl_createv(clog, 0, NULL, NULL, 318 CTLFLAG_PERMANENT, 319 CTLTYPE_STRING, "strategies", 320 SYSCTL_DESCR("List of bufq strategies present"), 321 sysctl_kern_bufq_strategies, 0, NULL, 0, 322 CTL_KERN, node->sysctl_num, CTL_CREATE, CTL_EOL); 323 } 324 } 325
Indexes created Sun Sep 21 20:09:37 GMT 2025