kernel - Introduce lightweight buffers
[dragonfly.git] / sys / kern / kern_subr.c
CommitLineData
984263bc
MD
1/*
2 * Copyright (c) 1982, 1986, 1991, 1993
3 * The Regents of the University of California. All rights reserved.
4 * (c) UNIX System Laboratories, Inc.
5 * All or some portions of this file are derived from material licensed
6 * to the University of California by American Telephone and Telegraph
7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
8 * the permission of UNIX System Laboratories, Inc.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. All advertising materials mentioning features or use of this software
19 * must display the following acknowledgement:
20 * This product includes software developed by the University of
21 * California, Berkeley and its contributors.
22 * 4. Neither the name of the University nor the names of its contributors
23 * may be used to endorse or promote products derived from this software
24 * without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 * SUCH DAMAGE.
37 *
38 * @(#)kern_subr.c 8.3 (Berkeley) 1/21/94
39 * $FreeBSD: src/sys/kern/kern_subr.c,v 1.31.2.2 2002/04/21 08:09:37 bde Exp $
fe57a30b 40 * $DragonFly: src/sys/kern/kern_subr.c,v 1.27 2007/01/29 20:44:02 tgen Exp $
984263bc
MD
41 */
42
6bd9bbba
HP
43#include "opt_ddb.h"
44
984263bc
MD
45#include <sys/param.h>
46#include <sys/systm.h>
47#include <sys/kernel.h>
48#include <sys/proc.h>
49#include <sys/malloc.h>
50#include <sys/lock.h>
51#include <sys/resourcevar.h>
cbd0496d
JS
52#include <sys/sysctl.h>
53#include <sys/uio.h>
984263bc 54#include <sys/vnode.h>
a358fd45 55#include <sys/thread2.h>
25e80b06 56#include <machine/limits.h>
984263bc 57
5c5185ae
SG
58#include <cpu/lwbuf.h>
59
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MD
60#include <vm/vm.h>
61#include <vm/vm_page.h>
62#include <vm/vm_map.h>
63
cbd0496d
JS
64SYSCTL_INT(_kern, KERN_IOV_MAX, iov_max, CTLFLAG_RD, NULL, UIO_MAXIOV,
65 "Maximum number of elements in an I/O vector; sysconf(_SC_IOV_MAX)");
66
1301b4d8
MD
67/*
68 * UIO_READ: copy the kernelspace cp to the user or kernelspace UIO
8ddc6004 69 * UIO_WRITE: copy the user or kernelspace UIO to the kernelspace cp
1301b4d8
MD
70 *
71 * For userspace UIO's, uio_td must be the current thread.
e54488bb
MD
72 *
73 * The syscall interface is responsible for limiting the length to
74 * ssize_t for things like read() or write() which return the bytes
75 * read or written as ssize_t. These functions work with unsigned
76 * lengths.
1301b4d8 77 */
984263bc 78int
e54488bb 79uiomove(caddr_t cp, size_t n, struct uio *uio)
984263bc 80{
1fd87d54 81 struct iovec *iov;
e54488bb 82 size_t cnt;
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MD
83 int error = 0;
84 int save = 0;
d16a8831 85 int baseticks = ticks;
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MD
86
87 KASSERT(uio->uio_rw == UIO_READ || uio->uio_rw == UIO_WRITE,
88 ("uiomove: mode"));
dadab5e9 89 KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == curthread,
984263bc
MD
90 ("uiomove proc"));
91
92 if (curproc) {
93 save = curproc->p_flag & P_DEADLKTREAT;
94 curproc->p_flag |= P_DEADLKTREAT;
95 }
96
97 while (n > 0 && uio->uio_resid) {
98 iov = uio->uio_iov;
99 cnt = iov->iov_len;
100 if (cnt == 0) {
101 uio->uio_iov++;
102 uio->uio_iovcnt--;
103 continue;
104 }
105 if (cnt > n)
106 cnt = n;
107
108 switch (uio->uio_segflg) {
109
110 case UIO_USERSPACE:
d16a8831 111 if (ticks - baseticks >= hogticks) {
984263bc 112 uio_yield();
d16a8831
MD
113 baseticks = ticks;
114 }
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MD
115 if (uio->uio_rw == UIO_READ)
116 error = copyout(cp, iov->iov_base, cnt);
117 else
118 error = copyin(iov->iov_base, cp, cnt);
119 if (error)
120 break;
121 break;
122
123 case UIO_SYSSPACE:
124 if (uio->uio_rw == UIO_READ)
125 bcopy((caddr_t)cp, iov->iov_base, cnt);
126 else
127 bcopy(iov->iov_base, (caddr_t)cp, cnt);
128 break;
129 case UIO_NOCOPY:
130 break;
131 }
656849c6 132 iov->iov_base = (char *)iov->iov_base + cnt;
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MD
133 iov->iov_len -= cnt;
134 uio->uio_resid -= cnt;
135 uio->uio_offset += cnt;
136 cp += cnt;
137 n -= cnt;
138 }
139 if (curproc)
140 curproc->p_flag = (curproc->p_flag & ~P_DEADLKTREAT) | save;
141 return (error);
142}
c7841cbe
MD
143
144/*
145 * Like uiomove() but copies zero-fill. Only allowed for UIO_READ,
146 * for obvious reasons.
147 */
148int
149uiomovez(size_t n, struct uio *uio)
150{
151 struct iovec *iov;
152 size_t cnt;
153 int error = 0;
154
155 KASSERT(uio->uio_rw == UIO_READ, ("uiomovez: mode"));
156 KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == curthread,
157 ("uiomove proc"));
158
159 while (n > 0 && uio->uio_resid) {
160 iov = uio->uio_iov;
161 cnt = iov->iov_len;
162 if (cnt == 0) {
163 uio->uio_iov++;
164 uio->uio_iovcnt--;
165 continue;
166 }
167 if (cnt > n)
168 cnt = n;
169
170 switch (uio->uio_segflg) {
171 case UIO_USERSPACE:
172 error = copyout(ZeroPage, iov->iov_base, cnt);
173 if (error)
174 break;
175 break;
176 case UIO_SYSSPACE:
177 bzero(iov->iov_base, cnt);
178 break;
179 case UIO_NOCOPY:
180 break;
181 }
182 iov->iov_base = (char *)iov->iov_base + cnt;
183 iov->iov_len -= cnt;
184 uio->uio_resid -= cnt;
185 uio->uio_offset += cnt;
186 n -= cnt;
187 }
188 return (error);
189}
190
25e80b06
DR
191/*
192 * Wrapper for uiomove() that validates the arguments against a known-good
e54488bb 193 * kernel buffer.
25e80b06
DR
194 */
195int
e54488bb 196uiomove_frombuf(void *buf, size_t buflen, struct uio *uio)
25e80b06 197{
e54488bb 198 size_t offset;
25e80b06 199
e54488bb
MD
200 offset = (size_t)uio->uio_offset;
201 if ((off_t)offset != uio->uio_offset)
25e80b06 202 return (EINVAL);
e54488bb 203 if (buflen == 0 || offset >= buflen)
25e80b06 204 return (0);
e54488bb 205 return (uiomove((char *)buf + offset, buflen - offset, uio));
984263bc
MD
206}
207
984263bc
MD
208/*
209 * Give next character to user as result of read.
210 */
211int
c972a82f 212ureadc(int c, struct uio *uio)
984263bc 213{
1fd87d54 214 struct iovec *iov;
656849c6 215 char *iov_base;
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MD
216
217again:
218 if (uio->uio_iovcnt == 0 || uio->uio_resid == 0)
219 panic("ureadc");
220 iov = uio->uio_iov;
221 if (iov->iov_len == 0) {
222 uio->uio_iovcnt--;
223 uio->uio_iov++;
224 goto again;
225 }
226 switch (uio->uio_segflg) {
227
228 case UIO_USERSPACE:
229 if (subyte(iov->iov_base, c) < 0)
230 return (EFAULT);
231 break;
232
233 case UIO_SYSSPACE:
656849c6
SW
234 iov_base = iov->iov_base;
235 *iov_base = c;
236 iov->iov_base = iov_base;
984263bc
MD
237 break;
238
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MD
239 case UIO_NOCOPY:
240 break;
241 }
656849c6 242 iov->iov_base = (char *)iov->iov_base + 1;
984263bc
MD
243 iov->iov_len--;
244 uio->uio_resid--;
245 uio->uio_offset++;
246 return (0);
247}
248
984263bc 249/*
1c86b25b
MD
250 * General routine to allocate a hash table. Make the hash table size a
251 * power of 2 greater or equal to the number of elements requested, and
252 * store the masking value in *hashmask.
984263bc
MD
253 */
254void *
c972a82f 255hashinit(int elements, struct malloc_type *type, u_long *hashmask)
984263bc
MD
256{
257 long hashsize;
258 LIST_HEAD(generic, generic) *hashtbl;
259 int i;
260
261 if (elements <= 0)
262 panic("hashinit: bad elements");
8f17cbc6 263 for (hashsize = 2; hashsize < elements; hashsize <<= 1)
984263bc 264 continue;
efda3bd0 265 hashtbl = kmalloc((u_long)hashsize * sizeof(*hashtbl), type, M_WAITOK);
984263bc
MD
266 for (i = 0; i < hashsize; i++)
267 LIST_INIT(&hashtbl[i]);
268 *hashmask = hashsize - 1;
269 return (hashtbl);
270}
271
c02197ac
MD
272/*
273 * This is a newer version which allocates a hash table of structures.
274 *
275 * The returned array will be zero'd. The caller is responsible for
276 * initializing the structures.
277 */
278void *
279hashinit_ext(int elements, size_t size, struct malloc_type *type,
280 u_long *hashmask)
281{
282 long hashsize;
283 void *hashtbl;
284
285 if (elements <= 0)
286 panic("hashinit: bad elements");
287 for (hashsize = 2; hashsize < elements; hashsize <<= 1)
288 continue;
289 hashtbl = kmalloc((size_t)hashsize * size, type, M_WAITOK | M_ZERO);
290 *hashmask = hashsize - 1;
291 return (hashtbl);
292}
293
984263bc
MD
294static int primes[] = { 1, 13, 31, 61, 127, 251, 509, 761, 1021, 1531, 2039,
295 2557, 3067, 3583, 4093, 4603, 5119, 5623, 6143, 6653,
296 7159, 7673, 8191, 12281, 16381, 24571, 32749 };
297#define NPRIMES (sizeof(primes) / sizeof(primes[0]))
298
299/*
300 * General routine to allocate a prime number sized hash table.
301 */
302void *
c972a82f 303phashinit(int elements, struct malloc_type *type, u_long *nentries)
984263bc
MD
304{
305 long hashsize;
306 LIST_HEAD(generic, generic) *hashtbl;
307 int i;
308
309 if (elements <= 0)
310 panic("phashinit: bad elements");
311 for (i = 1, hashsize = primes[1]; hashsize <= elements;) {
312 i++;
313 if (i == NPRIMES)
314 break;
315 hashsize = primes[i];
316 }
317 hashsize = primes[i - 1];
efda3bd0 318 hashtbl = kmalloc((u_long)hashsize * sizeof(*hashtbl), type, M_WAITOK);
984263bc
MD
319 for (i = 0; i < hashsize; i++)
320 LIST_INIT(&hashtbl[i]);
321 *nentries = hashsize;
322 return (hashtbl);
323}
75a872f8
DRJ
324
325/*
c02197ac
MD
326 * This is a newer version which allocates a hash table of structures
327 * in a prime-number size.
328 *
329 * The returned array will be zero'd. The caller is responsible for
330 * initializing the structures.
331 */
332void *
333phashinit_ext(int elements, size_t size, struct malloc_type *type,
334 u_long *nentries)
335{
336 long hashsize;
337 void *hashtbl;
338 int i;
339
340 if (elements <= 0)
341 panic("phashinit: bad elements");
342 for (i = 1, hashsize = primes[1]; hashsize <= elements;) {
343 i++;
344 if (i == NPRIMES)
345 break;
346 hashsize = primes[i];
347 }
348 hashsize = primes[i - 1];
349 hashtbl = kmalloc((size_t)hashsize * size, type, M_WAITOK | M_ZERO);
350 *nentries = hashsize;
351 return (hashtbl);
352}
353
354/*
75a872f8
DRJ
355 * Copyin an iovec. If the iovec array fits, use the preallocated small
356 * iovec structure. If it is too big, dynamically allocate an iovec array
357 * of sufficient size.
f832287e
MD
358 *
359 * MPSAFE
75a872f8
DRJ
360 */
361int
362iovec_copyin(struct iovec *uiov, struct iovec **kiov, struct iovec *siov,
e54488bb 363 size_t iov_cnt, size_t *iov_len)
75a872f8
DRJ
364{
365 struct iovec *iovp;
366 int error, i;
e54488bb 367 size_t len;
75a872f8 368
fe57a30b 369 if (iov_cnt > UIO_MAXIOV)
75a872f8 370 return EMSGSIZE;
fe57a30b 371 if (iov_cnt > UIO_SMALLIOV) {
75a872f8
DRJ
372 MALLOC(*kiov, struct iovec *, sizeof(struct iovec) * iov_cnt,
373 M_IOV, M_WAITOK);
374 } else {
375 *kiov = siov;
376 }
377 error = copyin(uiov, *kiov, iov_cnt * sizeof(struct iovec));
ef5c76d7
MD
378 if (error == 0) {
379 *iov_len = 0;
380 for (i = 0, iovp = *kiov; i < iov_cnt; i++, iovp++) {
381 /*
382 * Check for both *iov_len overflows and out of
383 * range iovp->iov_len's. We limit to the
384 * capabilities of signed integers.
e54488bb
MD
385 *
386 * GCC4 - overflow check opt requires assign/test.
ef5c76d7 387 */
e54488bb
MD
388 len = *iov_len + iovp->iov_len;
389 if (len < *iov_len)
ef5c76d7 390 error = EINVAL;
e54488bb 391 *iov_len = len;
ef5c76d7
MD
392 }
393 }
e54488bb
MD
394
395 /*
396 * From userland disallow iovec's which exceed the sized size
397 * limit as the system calls return ssize_t.
398 *
399 * NOTE: Internal kernel interfaces can handle the unsigned
400 * limit.
401 */
402 if (error == 0 && (ssize_t)*iov_len < 0)
403 error = EINVAL;
404
75a872f8
DRJ
405 if (error)
406 iovec_free(kiov, siov);
407 return (error);
408}
a358fd45
MD
409
410
411/*
412 * Copyright (c) 2004 Alan L. Cox <alc@cs.rice.edu>
413 * Copyright (c) 1982, 1986, 1991, 1993
414 * The Regents of the University of California. All rights reserved.
415 * (c) UNIX System Laboratories, Inc.
416 * All or some portions of this file are derived from material licensed
417 * to the University of California by American Telephone and Telegraph
418 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
419 * the permission of UNIX System Laboratories, Inc.
420 *
421 * Redistribution and use in source and binary forms, with or without
422 * modification, are permitted provided that the following conditions
423 * are met:
424 * 1. Redistributions of source code must retain the above copyright
425 * notice, this list of conditions and the following disclaimer.
426 * 2. Redistributions in binary form must reproduce the above copyright
427 * notice, this list of conditions and the following disclaimer in the
428 * documentation and/or other materials provided with the distribution.
429 * 4. Neither the name of the University nor the names of its contributors
430 * may be used to endorse or promote products derived from this software
431 * without specific prior written permission.
432 *
433 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
434 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
435 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
436 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
437 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
438 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
439 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
440 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
441 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
442 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
443 * SUCH DAMAGE.
444 *
445 * @(#)kern_subr.c 8.3 (Berkeley) 1/21/94
446 * $FreeBSD: src/sys/i386/i386/uio_machdep.c,v 1.1 2004/03/21 20:28:36 alc Exp $
447 */
448
449/*
5c5185ae 450 * Implement uiomove(9) from physical memory using lwbuf's to reduce
a358fd45
MD
451 * the creation and destruction of ephemeral mappings.
452 */
453int
e54488bb 454uiomove_fromphys(vm_page_t *ma, vm_offset_t offset, size_t n, struct uio *uio)
a358fd45 455{
5c5185ae 456 struct lwbuf *lwb;
a358fd45
MD
457 struct thread *td = curthread;
458 struct iovec *iov;
459 void *cp;
460 vm_offset_t page_offset;
461 vm_page_t m;
462 size_t cnt;
463 int error = 0;
464 int save = 0;
465
466 KASSERT(uio->uio_rw == UIO_READ || uio->uio_rw == UIO_WRITE,
467 ("uiomove_fromphys: mode"));
468 KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == curthread,
469 ("uiomove_fromphys proc"));
470
471 crit_enter();
472 save = td->td_flags & TDF_DEADLKTREAT;
473 td->td_flags |= TDF_DEADLKTREAT;
474 crit_exit();
475
476 while (n > 0 && uio->uio_resid) {
477 iov = uio->uio_iov;
478 cnt = iov->iov_len;
479 if (cnt == 0) {
480 uio->uio_iov++;
481 uio->uio_iovcnt--;
482 continue;
483 }
484 if (cnt > n)
485 cnt = n;
486 page_offset = offset & PAGE_MASK;
487 cnt = min(cnt, PAGE_SIZE - page_offset);
488 m = ma[offset >> PAGE_SHIFT];
5c5185ae
SG
489 lwb = lwbuf_alloc(m);
490 cp = (char *)lwbuf_kva(lwb) + page_offset;
a358fd45
MD
491 switch (uio->uio_segflg) {
492 case UIO_USERSPACE:
493 /*
494 * note: removed uioyield (it was the wrong place to
495 * put it).
496 */
497 if (uio->uio_rw == UIO_READ)
498 error = copyout(cp, iov->iov_base, cnt);
499 else
500 error = copyin(iov->iov_base, cp, cnt);
501 if (error) {
5c5185ae 502 lwbuf_free(lwb);
a358fd45
MD
503 goto out;
504 }
505 break;
506 case UIO_SYSSPACE:
507 if (uio->uio_rw == UIO_READ)
508 bcopy(cp, iov->iov_base, cnt);
509 else
510 bcopy(iov->iov_base, cp, cnt);
511 break;
512 case UIO_NOCOPY:
513 break;
514 }
5c5185ae 515 lwbuf_free(lwb);
a358fd45
MD
516 iov->iov_base = (char *)iov->iov_base + cnt;
517 iov->iov_len -= cnt;
518 uio->uio_resid -= cnt;
519 uio->uio_offset += cnt;
520 offset += cnt;
521 n -= cnt;
522 }
523out:
524 if (save == 0) {
525 crit_enter();
526 td->td_flags &= ~TDF_DEADLKTREAT;
527 crit_exit();
528 }
529 return (error);
530}
531