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
84static void sysctl_kern_bufq_strategies_setup(struct sysctllog **);
85static SLIST_HEAD(, bufq_strat) bufq_strat_list =
86 SLIST_HEAD_INITIALIZER(bufq_strat_list);
87
88static kmutex_t bufq_mutex;
89
90static struct sysctllog *sysctllog;
91
92void
93bufq_init(void)
94{
95
96 mutex_init(&bufq_mutex, MUTEX_DEFAULT, IPL_NONE);
97 sysctl_kern_bufq_strategies_setup(&sysctllog);
98}
99
100int
101bufq_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
112int
113bufq_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 */
130int
131bufq_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
215out:
216 return error;
217}
218
219void
220bufq_put(struct bufq_state *bufq, struct buf *bp)
221{
222
223 (*bufq->bq_put)(bufq, bp);
224}
225
226struct buf *
227bufq_get(struct bufq_state *bufq)
228{
229
230 return (*bufq->bq_get)(bufq, 1);
231}
232
233struct buf *
234bufq_peek(struct bufq_state *bufq)
235{
236
237 return (*bufq->bq_get)(bufq, 0);
238}
239
240struct buf *
241bufq_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 */
250void
251bufq_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 */
265void
266bufq_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 */
283const char *
284bufq_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 */
293void
294bufq_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
303static int
304docopy(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 }
319out:
320 if (error == 0) {
321 *bufoffp += datalen;
322 }
323
324 return error;
325}
326
327static int
328docopystr(char *buf, size_t *bufoffp, size_t buflen, const char *datap)
329{
330
331 return docopy(buf, bufoffp, buflen, datap, strlen(datap));
332}
333
334static int
335docopynul(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 */
345static int
346sysctl_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);
376out:
377 *oldlenp = off;
378 return error;
379}
380
381static void
382sysctl_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