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 | |