| 1 | /* $NetBSD: subr_bufq.c,v 1.25 2016/11/18 02:37:33 pgoyette 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 1.25 2016/11/18 02:37:33 pgoyette 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/sysctl.h> |
| 80 | #include <sys/module.h> |
| 81 | |
| 82 | #define STRAT_MATCH(id, bs) (strcmp((id), (bs)->bs_name) == 0) |
| 83 | |
| 84 | static void sysctl_kern_bufq_strategies_setup(struct sysctllog **); |
| 85 | static SLIST_HEAD(, bufq_strat) bufq_strat_list = |
| 86 | SLIST_HEAD_INITIALIZER(bufq_strat_list); |
| 87 | |
| 88 | static kmutex_t bufq_mutex; |
| 89 | |
| 90 | static struct sysctllog *sysctllog; |
| 91 | |
| 92 | void |
| 93 | bufq_init(void) |
| 94 | { |
| 95 | |
| 96 | mutex_init(&bufq_mutex, MUTEX_DEFAULT, IPL_NONE); |
| 97 | sysctl_kern_bufq_strategies_setup(&sysctllog); |
| 98 | } |
| 99 | |
| 100 | int |
| 101 | bufq_register(struct bufq_strat *bs) |
| 102 | { |
| 103 | |
| 104 | mutex_enter(&bufq_mutex); |
| 105 | SLIST_INSERT_HEAD(&bufq_strat_list, bs, bs_next); |
| 106 | bs->bs_refcnt = 0; |
| 107 | mutex_exit(&bufq_mutex); |
| 108 | |
| 109 | return 0; |
| 110 | } |
| 111 | |
| 112 | int |
| 113 | bufq_unregister(struct bufq_strat *bs) |
| 114 | { |
| 115 | |
| 116 | mutex_enter(&bufq_mutex); |
| 117 | if (bs->bs_refcnt != 0) { |
| 118 | mutex_exit(&bufq_mutex); |
| 119 | return EBUSY; |
| 120 | } |
| 121 | SLIST_REMOVE(&bufq_strat_list, bs, bufq_strat, bs_next); |
| 122 | mutex_exit(&bufq_mutex); |
| 123 | |
| 124 | return 0; |
| 125 | } |
| 126 | |
| 127 | /* |
| 128 | * Create a device buffer queue. |
| 129 | */ |
| 130 | int |
| 131 | bufq_alloc(struct bufq_state **bufqp, const char *strategy, int flags) |
| 132 | { |
| 133 | struct bufq_strat *bsp, *it; |
| 134 | struct bufq_state *bufq; |
| 135 | int error = 0; |
| 136 | u_int gen; |
| 137 | bool found_exact; |
| 138 | char module_name[MAXPATHLEN]; |
| 139 | |
| 140 | KASSERT((flags & BUFQ_EXACT) == 0 || strategy != BUFQ_STRAT_ANY); |
| 141 | |
| 142 | switch (flags & BUFQ_SORT_MASK) { |
| 143 | case BUFQ_SORT_RAWBLOCK: |
| 144 | case BUFQ_SORT_CYLINDER: |
| 145 | break; |
| 146 | case 0: |
| 147 | /* |
| 148 | * for strategies which don't care about block numbers. |
| 149 | * eg. fcfs |
| 150 | */ |
| 151 | flags |= BUFQ_SORT_RAWBLOCK; |
| 152 | break; |
| 153 | default: |
| 154 | panic("bufq_alloc: sort out of range" ); |
| 155 | } |
| 156 | |
| 157 | /* |
| 158 | * select strategy. |
| 159 | * if a strategy specified by flags is found, use it. |
| 160 | * otherwise, select one with the largest bs_prio. |
| 161 | */ |
| 162 | mutex_enter(&bufq_mutex); |
| 163 | do { |
| 164 | gen = module_gen; |
| 165 | bsp = NULL; |
| 166 | found_exact = false; |
| 167 | |
| 168 | SLIST_FOREACH(it, &bufq_strat_list, bs_next) { |
| 169 | if (strategy != BUFQ_STRAT_ANY && |
| 170 | STRAT_MATCH(strategy, (it))) { |
| 171 | bsp = it; |
| 172 | found_exact = true; |
| 173 | break; |
| 174 | } |
| 175 | if (bsp == NULL || (it)->bs_prio > bsp->bs_prio) |
| 176 | bsp = it; |
| 177 | } |
| 178 | if (strategy == BUFQ_STRAT_ANY || found_exact) |
| 179 | break; |
| 180 | |
| 181 | /* Try to autoload device module */ |
| 182 | strlcpy(module_name, "bufq_" , sizeof(module_name)); |
| 183 | strlcat(module_name, strategy, sizeof(module_name)); |
| 184 | mutex_exit(&bufq_mutex); |
| 185 | (void) module_autoload(module_name, MODULE_CLASS_BUFQ); |
| 186 | mutex_enter(&bufq_mutex); |
| 187 | } while (gen != module_gen); |
| 188 | |
| 189 | if (bsp == NULL) { |
| 190 | panic("bufq_alloc: no strategy" ); |
| 191 | } |
| 192 | if (strategy != BUFQ_STRAT_ANY && !found_exact) { |
| 193 | if ((flags & BUFQ_EXACT)) { |
| 194 | error = ENOENT; |
| 195 | mutex_exit(&bufq_mutex); |
| 196 | goto out; |
| 197 | } |
| 198 | #if defined(DEBUG) |
| 199 | printf("bufq_alloc: '%s' is not available. using '%s'.\n" , |
| 200 | strategy, bsp->bs_name); |
| 201 | #endif |
| 202 | } |
| 203 | #if defined(BUFQ_DEBUG) |
| 204 | /* XXX aprint? */ |
| 205 | printf("bufq_alloc: using '%s'\n" , bsp->bs_name); |
| 206 | #endif |
| 207 | |
| 208 | bsp->bs_refcnt++; |
| 209 | mutex_exit(&bufq_mutex); |
| 210 | *bufqp = bufq = kmem_zalloc(sizeof(*bufq), KM_SLEEP); |
| 211 | bufq->bq_flags = flags; |
| 212 | bufq->bq_strat = bsp; |
| 213 | (*bsp->bs_initfn)(bufq); |
| 214 | |
| 215 | out: |
| 216 | return error; |
| 217 | } |
| 218 | |
| 219 | void |
| 220 | bufq_put(struct bufq_state *bufq, struct buf *bp) |
| 221 | { |
| 222 | |
| 223 | (*bufq->bq_put)(bufq, bp); |
| 224 | } |
| 225 | |
| 226 | struct buf * |
| 227 | bufq_get(struct bufq_state *bufq) |
| 228 | { |
| 229 | |
| 230 | return (*bufq->bq_get)(bufq, 1); |
| 231 | } |
| 232 | |
| 233 | struct buf * |
| 234 | bufq_peek(struct bufq_state *bufq) |
| 235 | { |
| 236 | |
| 237 | return (*bufq->bq_get)(bufq, 0); |
| 238 | } |
| 239 | |
| 240 | struct buf * |
| 241 | bufq_cancel(struct bufq_state *bufq, struct buf *bp) |
| 242 | { |
| 243 | |
| 244 | return (*bufq->bq_cancel)(bufq, bp); |
| 245 | } |
| 246 | |
| 247 | /* |
| 248 | * Drain a device buffer queue. |
| 249 | */ |
| 250 | void |
| 251 | bufq_drain(struct bufq_state *bufq) |
| 252 | { |
| 253 | struct buf *bp; |
| 254 | |
| 255 | while ((bp = bufq_get(bufq)) != NULL) { |
| 256 | bp->b_error = EIO; |
| 257 | bp->b_resid = bp->b_bcount; |
| 258 | biodone(bp); |
| 259 | } |
| 260 | } |
| 261 | |
| 262 | /* |
| 263 | * Destroy a device buffer queue. |
| 264 | */ |
| 265 | void |
| 266 | bufq_free(struct bufq_state *bufq) |
| 267 | { |
| 268 | |
| 269 | KASSERT(bufq_peek(bufq) == NULL); |
| 270 | |
| 271 | bufq->bq_fini(bufq); |
| 272 | |
| 273 | mutex_enter(&bufq_mutex); |
| 274 | bufq->bq_strat->bs_refcnt--; |
| 275 | mutex_exit(&bufq_mutex); |
| 276 | |
| 277 | kmem_free(bufq, sizeof(*bufq)); |
| 278 | } |
| 279 | |
| 280 | /* |
| 281 | * get a strategy identifier of a buffer queue. |
| 282 | */ |
| 283 | const char * |
| 284 | bufq_getstrategyname(struct bufq_state *bufq) |
| 285 | { |
| 286 | |
| 287 | return bufq->bq_strat->bs_name; |
| 288 | } |
| 289 | |
| 290 | /* |
| 291 | * move all requests on a buffer queue to another. |
| 292 | */ |
| 293 | void |
| 294 | bufq_move(struct bufq_state *dst, struct bufq_state *src) |
| 295 | { |
| 296 | struct buf *bp; |
| 297 | |
| 298 | while ((bp = bufq_get(src)) != NULL) { |
| 299 | bufq_put(dst, bp); |
| 300 | } |
| 301 | } |
| 302 | |
| 303 | static int |
| 304 | docopy(char *buf, size_t *bufoffp, size_t buflen, |
| 305 | const char *datap, size_t datalen) |
| 306 | { |
| 307 | int error = 0; |
| 308 | |
| 309 | if (buf != NULL && datalen > 0) { |
| 310 | |
| 311 | if (*bufoffp + datalen > buflen) { |
| 312 | goto out; |
| 313 | } |
| 314 | error = copyout(datap, buf + *bufoffp, datalen); |
| 315 | if (error) { |
| 316 | goto out; |
| 317 | } |
| 318 | } |
| 319 | out: |
| 320 | if (error == 0) { |
| 321 | *bufoffp += datalen; |
| 322 | } |
| 323 | |
| 324 | return error; |
| 325 | } |
| 326 | |
| 327 | static int |
| 328 | docopystr(char *buf, size_t *bufoffp, size_t buflen, const char *datap) |
| 329 | { |
| 330 | |
| 331 | return docopy(buf, bufoffp, buflen, datap, strlen(datap)); |
| 332 | } |
| 333 | |
| 334 | static int |
| 335 | docopynul(char *buf, size_t *bufoffp, size_t buflen) |
| 336 | { |
| 337 | |
| 338 | return docopy(buf, bufoffp, buflen, "" , 1); |
| 339 | } |
| 340 | |
| 341 | /* |
| 342 | * sysctl function that will print all bufq strategies |
| 343 | * currently available to the kernel. |
| 344 | */ |
| 345 | static int |
| 346 | sysctl_kern_bufq_strategies(SYSCTLFN_ARGS) |
| 347 | { |
| 348 | const struct bufq_strat *bq_strat; |
| 349 | const char *delim = "" ; |
| 350 | size_t off = 0; |
| 351 | size_t buflen = *oldlenp; |
| 352 | int error; |
| 353 | |
| 354 | SLIST_FOREACH(bq_strat, &bufq_strat_list, bs_next) { |
| 355 | error = docopystr(oldp, &off, buflen, delim); |
| 356 | if (error) { |
| 357 | goto out; |
| 358 | } |
| 359 | error = docopystr(oldp, &off, buflen, (bq_strat)->bs_name); |
| 360 | if (error) { |
| 361 | goto out; |
| 362 | } |
| 363 | delim = " " ; |
| 364 | } |
| 365 | |
| 366 | /* In case there are no registered strategies ... */ |
| 367 | if (off == 0) { |
| 368 | error = docopystr(oldp, &off, buflen, "NULL" ); |
| 369 | if (error) { |
| 370 | goto out; |
| 371 | } |
| 372 | } |
| 373 | |
| 374 | /* NUL terminate */ |
| 375 | error = docopynul(oldp, &off, buflen); |
| 376 | out: |
| 377 | *oldlenp = off; |
| 378 | return error; |
| 379 | } |
| 380 | |
| 381 | static void |
| 382 | sysctl_kern_bufq_strategies_setup(struct sysctllog **clog) |
| 383 | { |
| 384 | const struct sysctlnode *node; |
| 385 | |
| 386 | node = NULL; |
| 387 | sysctl_createv(clog, 0, NULL, &node, |
| 388 | CTLFLAG_PERMANENT, |
| 389 | CTLTYPE_NODE, "bufq" , |
| 390 | SYSCTL_DESCR("buffer queue subtree" ), |
| 391 | NULL, 0, NULL, 0, |
| 392 | CTL_KERN, CTL_CREATE, CTL_EOL); |
| 393 | if (node != NULL) { |
| 394 | sysctl_createv(clog, 0, NULL, NULL, |
| 395 | CTLFLAG_PERMANENT, |
| 396 | CTLTYPE_STRING, "strategies" , |
| 397 | SYSCTL_DESCR("List of bufq strategies present" ), |
| 398 | sysctl_kern_bufq_strategies, 0, NULL, 0, |
| 399 | CTL_KERN, node->sysctl_num, CTL_CREATE, CTL_EOL); |
| 400 | } |
| 401 | } |
| 402 | |