1 /* $NetBSD: subr_bufq.c,v 1.27 2019/02/17 23:17:41 bad 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 1.27 2019/02/17 23:17:41 bad 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
bufq_init(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
bufq_register(struct bufq_strat * bs)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
bufq_unregister(struct bufq_strat * bs)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
bufq_alloc(struct bufq_state ** bufqp,const char * strategy,int flags)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 strategy_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 the bufq strategy module */
182 strlcpy(strategy_module_name, "bufq_",
183 sizeof(strategy_module_name));
184 strlcat(strategy_module_name, strategy,
185 sizeof(strategy_module_name));
186 mutex_exit(&bufq_mutex);
187 (void) module_autoload(strategy_module_name, MODULE_CLASS_BUFQ);
188 mutex_enter(&bufq_mutex);
189 } while (gen != module_gen);
190
191 if (bsp == NULL) {
192 panic("bufq_alloc: no strategy");
193 }
194 if (strategy != BUFQ_STRAT_ANY && !found_exact) {
195 if ((flags & BUFQ_EXACT)) {
196 error = ENOENT;
197 mutex_exit(&bufq_mutex);
198 goto out;
199 }
200 #if defined(DEBUG)
201 printf("bufq_alloc: '%s' is not available. using '%s'.\n",
202 strategy, bsp->bs_name);
203 #endif
204 }
205 #if defined(BUFQ_DEBUG)
206 /* XXX aprint? */
207 printf("bufq_alloc: using '%s'\n", bsp->bs_name);
208 #endif
209
210 bsp->bs_refcnt++;
211 mutex_exit(&bufq_mutex);
212 *bufqp = bufq = kmem_zalloc(sizeof(*bufq), KM_SLEEP);
213 bufq->bq_flags = flags;
214 bufq->bq_strat = bsp;
215 (*bsp->bs_initfn)(bufq);
216
217 out:
218 return error;
219 }
220
221 void
bufq_put(struct bufq_state * bufq,struct buf * bp)222 bufq_put(struct bufq_state *bufq, struct buf *bp)
223 {
224
225 (*bufq->bq_put)(bufq, bp);
226 }
227
228 struct buf *
bufq_get(struct bufq_state * bufq)229 bufq_get(struct bufq_state *bufq)
230 {
231
232 return (*bufq->bq_get)(bufq, 1);
233 }
234
235 struct buf *
bufq_peek(struct bufq_state * bufq)236 bufq_peek(struct bufq_state *bufq)
237 {
238
239 return (*bufq->bq_get)(bufq, 0);
240 }
241
242 struct buf *
bufq_cancel(struct bufq_state * bufq,struct buf * bp)243 bufq_cancel(struct bufq_state *bufq, struct buf *bp)
244 {
245
246 return (*bufq->bq_cancel)(bufq, bp);
247 }
248
249 /*
250 * Drain a device buffer queue.
251 */
252 void
bufq_drain(struct bufq_state * bufq)253 bufq_drain(struct bufq_state *bufq)
254 {
255 struct buf *bp;
256
257 while ((bp = bufq_get(bufq)) != NULL) {
258 bp->b_error = EIO;
259 bp->b_resid = bp->b_bcount;
260 biodone(bp);
261 }
262 }
263
264 /*
265 * Destroy a device buffer queue.
266 */
267 void
bufq_free(struct bufq_state * bufq)268 bufq_free(struct bufq_state *bufq)
269 {
270
271 KASSERT(bufq_peek(bufq) == NULL);
272
273 bufq->bq_fini(bufq);
274
275 mutex_enter(&bufq_mutex);
276 bufq->bq_strat->bs_refcnt--;
277 mutex_exit(&bufq_mutex);
278
279 kmem_free(bufq, sizeof(*bufq));
280 }
281
282 /*
283 * get a strategy identifier of a buffer queue.
284 */
285 const char *
bufq_getstrategyname(struct bufq_state * bufq)286 bufq_getstrategyname(struct bufq_state *bufq)
287 {
288
289 return bufq->bq_strat->bs_name;
290 }
291
292 /*
293 * move all requests on a buffer queue to another.
294 */
295 void
bufq_move(struct bufq_state * dst,struct bufq_state * src)296 bufq_move(struct bufq_state *dst, struct bufq_state *src)
297 {
298 struct buf *bp;
299
300 while ((bp = bufq_get(src)) != NULL) {
301 bufq_put(dst, bp);
302 }
303 }
304
305 static int
docopy(char * buf,size_t * bufoffp,size_t buflen,const char * datap,size_t datalen)306 docopy(char *buf, size_t *bufoffp, size_t buflen,
307 const char *datap, size_t datalen)
308 {
309 int error = 0;
310
311 if (buf != NULL && datalen > 0) {
312
313 if (*bufoffp + datalen > buflen) {
314 goto out;
315 }
316 error = copyout(datap, buf + *bufoffp, datalen);
317 if (error) {
318 goto out;
319 }
320 }
321 out:
322 if (error == 0) {
323 *bufoffp += datalen;
324 }
325
326 return error;
327 }
328
329 static int
docopystr(char * buf,size_t * bufoffp,size_t buflen,const char * datap)330 docopystr(char *buf, size_t *bufoffp, size_t buflen, const char *datap)
331 {
332
333 return docopy(buf, bufoffp, buflen, datap, strlen(datap));
334 }
335
336 static int
docopynul(char * buf,size_t * bufoffp,size_t buflen)337 docopynul(char *buf, size_t *bufoffp, size_t buflen)
338 {
339
340 return docopy(buf, bufoffp, buflen, "", 1);
341 }
342
343 /*
344 * sysctl function that will print all bufq strategies
345 * currently available to the kernel.
346 */
347 static int
sysctl_kern_bufq_strategies(SYSCTLFN_ARGS)348 sysctl_kern_bufq_strategies(SYSCTLFN_ARGS)
349 {
350 const struct bufq_strat *bq_strat;
351 const char *delim = "";
352 size_t off = 0;
353 size_t buflen = *oldlenp;
354 int error;
355
356 SLIST_FOREACH(bq_strat, &bufq_strat_list, bs_next) {
357 error = docopystr(oldp, &off, buflen, delim);
358 if (error) {
359 goto out;
360 }
361 error = docopystr(oldp, &off, buflen, (bq_strat)->bs_name);
362 if (error) {
363 goto out;
364 }
365 delim = " ";
366 }
367
368 /* In case there are no registered strategies ... */
369 if (off == 0) {
370 error = docopystr(oldp, &off, buflen, "NULL");
371 if (error) {
372 goto out;
373 }
374 }
375
376 /* NUL terminate */
377 error = docopynul(oldp, &off, buflen);
378 out:
379 *oldlenp = off;
380 return error;
381 }
382
383 static void
sysctl_kern_bufq_strategies_setup(struct sysctllog ** clog)384 sysctl_kern_bufq_strategies_setup(struct sysctllog **clog)
385 {
386 const struct sysctlnode *node;
387
388 node = NULL;
389 sysctl_createv(clog, 0, NULL, &node,
390 CTLFLAG_PERMANENT,
391 CTLTYPE_NODE, "bufq",
392 SYSCTL_DESCR("buffer queue subtree"),
393 NULL, 0, NULL, 0,
394 CTL_KERN, CTL_CREATE, CTL_EOL);
395 if (node != NULL) {
396 sysctl_createv(clog, 0, NULL, NULL,
397 CTLFLAG_PERMANENT,
398 CTLTYPE_STRING, "strategies",
399 SYSCTL_DESCR("List of bufq strategies present"),
400 sysctl_kern_bufq_strategies, 0, NULL, 0,
401 CTL_KERN, node->sysctl_num, CTL_CREATE, CTL_EOL);
402 }
403 }
404