sys/kern/subr_bufq.c

   1 /*      $NetBSD: subr_bufq.c,v 1.19 2009/09/16 15:23:04 pooka 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 1.19 2009/09/16 15:23:04 pooka 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         sysctl_createv(clog, 0, NULL, NULL,
 334                         CTLFLAG_PERMANENT,
 335                         CTLTYPE_NODE, "kern", NULL,
 336                         NULL, 0, NULL, 0,
 337                         CTL_KERN, CTL_EOL);
 338         node = NULL;
 339         sysctl_createv(clog, 0, NULL, &node,
 340                         CTLFLAG_PERMANENT,
 341                         CTLTYPE_NODE, "bufq",
 342                         SYSCTL_DESCR("buffer queue subtree"),
 343                         NULL, 0, NULL, 0,
 344                         CTL_KERN, CTL_CREATE, CTL_EOL);
 345         if (node != NULL) {
 346                 sysctl_createv(clog, 0, NULL, NULL,
 347                         CTLFLAG_PERMANENT,
 348                         CTLTYPE_STRING, "strategies",
 349                         SYSCTL_DESCR("List of bufq strategies present"),
 350                         sysctl_kern_bufq_strategies, 0, NULL, 0,
 351                         CTL_KERN, node->sysctl_num, CTL_CREATE, CTL_EOL);
 352         }
 353 }