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
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 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
217out:
218	return error;
219}
220
221void
222bufq_put(struct bufq_state *bufq, struct buf *bp)
223{
224
225	(*bufq->bq_put)(bufq, bp);
226}
227
228struct buf *
229bufq_get(struct bufq_state *bufq)
230{
231
232	return (*bufq->bq_get)(bufq, 1);
233}
234
235struct buf *
236bufq_peek(struct bufq_state *bufq)
237{
238
239	return (*bufq->bq_get)(bufq, 0);
240}
241
242struct buf *
243bufq_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 */
252void
253bufq_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 */
267void
268bufq_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 */
285const char *
286bufq_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 */
295void
296bufq_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
305static int
306docopy(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	}
321out:
322	if (error == 0) {
323		*bufoffp += datalen;
324	}
325
326	return error;
327}
328
329static int
330docopystr(char *buf, size_t *bufoffp, size_t buflen, const char *datap)
331{
332
333	return docopy(buf, bufoffp, buflen, datap, strlen(datap));
334}
335
336static int
337docopynul(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 */
347static int
348sysctl_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);
378out:
379	*oldlenp = off;
380	return error;
381}
382
383static void
384sysctl_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