FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_mbuf.c
1 /*-
2 * Copyright (c) 2004, 2005,
3 * Bosko Milekic <bmilekic@FreeBSD.org>. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice unmodified, this list of conditions and the following
10 * disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28 #include <sys/cdefs.h>
29 __FBSDID("$FreeBSD: releng/7.3/sys/kern/kern_mbuf.c 196838 2009-09-04 19:59:32Z jhb $");
30
31 #include "opt_mac.h"
32 #include "opt_param.h"
33
34 #include <sys/param.h>
35 #include <sys/malloc.h>
36 #include <sys/systm.h>
37 #include <sys/mbuf.h>
38 #include <sys/domain.h>
39 #include <sys/eventhandler.h>
40 #include <sys/kernel.h>
41 #include <sys/protosw.h>
42 #include <sys/smp.h>
43 #include <sys/sysctl.h>
44
45 #include <security/mac/mac_framework.h>
46
47 #include <vm/vm.h>
48 #include <vm/vm_extern.h>
49 #include <vm/vm_kern.h>
50 #include <vm/vm_page.h>
51 #include <vm/uma.h>
52 #include <vm/uma_int.h>
53 #include <vm/uma_dbg.h>
54
55 /*
56 * In FreeBSD, Mbufs and Mbuf Clusters are allocated from UMA
57 * Zones.
58 *
59 * Mbuf Clusters (2K, contiguous) are allocated from the Cluster
60 * Zone. The Zone can be capped at kern.ipc.nmbclusters, if the
61 * administrator so desires.
62 *
63 * Mbufs are allocated from a UMA Master Zone called the Mbuf
64 * Zone.
65 *
66 * Additionally, FreeBSD provides a Packet Zone, which it
67 * configures as a Secondary Zone to the Mbuf Master Zone,
68 * thus sharing backend Slab kegs with the Mbuf Master Zone.
69 *
70 * Thus common-case allocations and locking are simplified:
71 *
72 * m_clget() m_getcl()
73 * | |
74 * | .------------>[(Packet Cache)] m_get(), m_gethdr()
75 * | | [ Packet ] |
76 * [(Cluster Cache)] [ Secondary ] [ (Mbuf Cache) ]
77 * [ Cluster Zone ] [ Zone ] [ Mbuf Master Zone ]
78 * | \________ |
79 * [ Cluster Keg ] \ /
80 * | [ Mbuf Keg ]
81 * [ Cluster Slabs ] |
82 * | [ Mbuf Slabs ]
83 * \____________(VM)_________________/
84 *
85 *
86 * Whenever an object is allocated with uma_zalloc() out of
87 * one of the Zones its _ctor_ function is executed. The same
88 * for any deallocation through uma_zfree() the _dtor_ function
89 * is executed.
90 *
91 * Caches are per-CPU and are filled from the Master Zone.
92 *
93 * Whenever an object is allocated from the underlying global
94 * memory pool it gets pre-initialized with the _zinit_ functions.
95 * When the Keg's are overfull objects get decomissioned with
96 * _zfini_ functions and free'd back to the global memory pool.
97 *
98 */
99
100 int nmbclusters; /* limits number of mbuf clusters */
101 int nmbjumbop; /* limits number of page size jumbo clusters */
102 int nmbjumbo9; /* limits number of 9k jumbo clusters */
103 int nmbjumbo16; /* limits number of 16k jumbo clusters */
104 struct mbstat mbstat;
105
106 /*
107 * tunable_mbinit() has to be run before init_maxsockets() thus
108 * the SYSINIT order below is SI_ORDER_MIDDLE while init_maxsockets()
109 * runs at SI_ORDER_ANY.
110 */
111 static void
112 tunable_mbinit(void *dummy)
113 {
114
115 /* This has to be done before VM init. */
116 nmbclusters = 1024 + maxusers * 64;
117 nmbjumbop = nmbclusters / 2;
118 nmbjumbo9 = nmbjumbop / 2;
119 nmbjumbo16 = nmbjumbo9 / 2;
120 TUNABLE_INT_FETCH("kern.ipc.nmbclusters", &nmbclusters);
121 }
122 SYSINIT(tunable_mbinit, SI_SUB_TUNABLES, SI_ORDER_MIDDLE, tunable_mbinit, NULL);
123
124 /* XXX: These should be tuneables. Can't change UMA limits on the fly. */
125 static int
126 sysctl_nmbclusters(SYSCTL_HANDLER_ARGS)
127 {
128 int error, newnmbclusters;
129
130 newnmbclusters = nmbclusters;
131 error = sysctl_handle_int(oidp, &newnmbclusters, 0, req);
132 if (error == 0 && req->newptr) {
133 if (newnmbclusters > nmbclusters) {
134 nmbclusters = newnmbclusters;
135 uma_zone_set_max(zone_clust, nmbclusters);
136 EVENTHANDLER_INVOKE(nmbclusters_change);
137 } else
138 error = EINVAL;
139 }
140 return (error);
141 }
142 SYSCTL_PROC(_kern_ipc, OID_AUTO, nmbclusters, CTLTYPE_INT|CTLFLAG_RW,
143 &nmbclusters, 0, sysctl_nmbclusters, "IU",
144 "Maximum number of mbuf clusters allowed");
145
146 static int
147 sysctl_nmbjumbop(SYSCTL_HANDLER_ARGS)
148 {
149 int error, newnmbjumbop;
150
151 newnmbjumbop = nmbjumbop;
152 error = sysctl_handle_int(oidp, &newnmbjumbop, 0, req);
153 if (error == 0 && req->newptr) {
154 if (newnmbjumbop> nmbjumbop) {
155 nmbjumbop = newnmbjumbop;
156 uma_zone_set_max(zone_jumbop, nmbjumbop);
157 } else
158 error = EINVAL;
159 }
160 return (error);
161 }
162 SYSCTL_PROC(_kern_ipc, OID_AUTO, nmbjumbop, CTLTYPE_INT|CTLFLAG_RW,
163 &nmbjumbop, 0, sysctl_nmbjumbop, "IU",
164 "Maximum number of mbuf page size jumbo clusters allowed");
165
166
167 static int
168 sysctl_nmbjumbo9(SYSCTL_HANDLER_ARGS)
169 {
170 int error, newnmbjumbo9;
171
172 newnmbjumbo9 = nmbjumbo9;
173 error = sysctl_handle_int(oidp, &newnmbjumbo9, 0, req);
174 if (error == 0 && req->newptr) {
175 if (newnmbjumbo9> nmbjumbo9) {
176 nmbjumbo9 = newnmbjumbo9;
177 uma_zone_set_max(zone_jumbo9, nmbjumbo9);
178 } else
179 error = EINVAL;
180 }
181 return (error);
182 }
183 SYSCTL_PROC(_kern_ipc, OID_AUTO, nmbjumbo9, CTLTYPE_INT|CTLFLAG_RW,
184 &nmbjumbo9, 0, sysctl_nmbjumbo9, "IU",
185 "Maximum number of mbuf 9k jumbo clusters allowed");
186
187 static int
188 sysctl_nmbjumbo16(SYSCTL_HANDLER_ARGS)
189 {
190 int error, newnmbjumbo16;
191
192 newnmbjumbo16 = nmbjumbo16;
193 error = sysctl_handle_int(oidp, &newnmbjumbo16, 0, req);
194 if (error == 0 && req->newptr) {
195 if (newnmbjumbo16> nmbjumbo16) {
196 nmbjumbo16 = newnmbjumbo16;
197 uma_zone_set_max(zone_jumbo16, nmbjumbo16);
198 } else
199 error = EINVAL;
200 }
201 return (error);
202 }
203 SYSCTL_PROC(_kern_ipc, OID_AUTO, nmbjumbo16, CTLTYPE_INT|CTLFLAG_RW,
204 &nmbjumbo16, 0, sysctl_nmbjumbo16, "IU",
205 "Maximum number of mbuf 16k jumbo clusters allowed");
206
207
208
209 SYSCTL_STRUCT(_kern_ipc, OID_AUTO, mbstat, CTLFLAG_RD, &mbstat, mbstat,
210 "Mbuf general information and statistics");
211
212 /*
213 * Zones from which we allocate.
214 */
215 uma_zone_t zone_mbuf;
216 uma_zone_t zone_clust;
217 uma_zone_t zone_pack;
218 uma_zone_t zone_jumbop;
219 uma_zone_t zone_jumbo9;
220 uma_zone_t zone_jumbo16;
221 uma_zone_t zone_ext_refcnt;
222
223 /*
224 * Local prototypes.
225 */
226 static int mb_ctor_mbuf(void *, int, void *, int);
227 static int mb_ctor_clust(void *, int, void *, int);
228 static int mb_ctor_pack(void *, int, void *, int);
229 static void mb_dtor_mbuf(void *, int, void *);
230 static void mb_dtor_clust(void *, int, void *);
231 static void mb_dtor_pack(void *, int, void *);
232 static int mb_zinit_pack(void *, int, int);
233 static void mb_zfini_pack(void *, int);
234
235 static void mb_reclaim(void *);
236 static void mbuf_init(void *);
237 static void *mbuf_jumbo_alloc(uma_zone_t, int, u_int8_t *, int);
238
239 /* Ensure that MSIZE doesn't break dtom() - it must be a power of 2 */
240 CTASSERT((((MSIZE - 1) ^ MSIZE) + 1) >> 1 == MSIZE);
241
242 /*
243 * Initialize FreeBSD Network buffer allocation.
244 */
245 SYSINIT(mbuf, SI_SUB_MBUF, SI_ORDER_FIRST, mbuf_init, NULL);
246 static void
247 mbuf_init(void *dummy)
248 {
249
250 /*
251 * Configure UMA zones for Mbufs, Clusters, and Packets.
252 */
253 zone_mbuf = uma_zcreate(MBUF_MEM_NAME, MSIZE,
254 mb_ctor_mbuf, mb_dtor_mbuf,
255 #ifdef INVARIANTS
256 trash_init, trash_fini,
257 #else
258 NULL, NULL,
259 #endif
260 MSIZE - 1, UMA_ZONE_MAXBUCKET);
261
262 zone_clust = uma_zcreate(MBUF_CLUSTER_MEM_NAME, MCLBYTES,
263 mb_ctor_clust, mb_dtor_clust,
264 #ifdef INVARIANTS
265 trash_init, trash_fini,
266 #else
267 NULL, NULL,
268 #endif
269 UMA_ALIGN_PTR, UMA_ZONE_REFCNT);
270 if (nmbclusters > 0)
271 uma_zone_set_max(zone_clust, nmbclusters);
272
273 zone_pack = uma_zsecond_create(MBUF_PACKET_MEM_NAME, mb_ctor_pack,
274 mb_dtor_pack, mb_zinit_pack, mb_zfini_pack, zone_mbuf);
275
276 /* Make jumbo frame zone too. Page size, 9k and 16k. */
277 zone_jumbop = uma_zcreate(MBUF_JUMBOP_MEM_NAME, MJUMPAGESIZE,
278 mb_ctor_clust, mb_dtor_clust,
279 #ifdef INVARIANTS
280 trash_init, trash_fini,
281 #else
282 NULL, NULL,
283 #endif
284 UMA_ALIGN_PTR, UMA_ZONE_REFCNT);
285 if (nmbjumbop > 0)
286 uma_zone_set_max(zone_jumbop, nmbjumbop);
287
288 zone_jumbo9 = uma_zcreate(MBUF_JUMBO9_MEM_NAME, MJUM9BYTES,
289 mb_ctor_clust, mb_dtor_clust,
290 #ifdef INVARIANTS
291 trash_init, trash_fini,
292 #else
293 NULL, NULL,
294 #endif
295 UMA_ALIGN_PTR, UMA_ZONE_REFCNT);
296 if (nmbjumbo9 > 0)
297 uma_zone_set_max(zone_jumbo9, nmbjumbo9);
298 uma_zone_set_allocf(zone_jumbo9, mbuf_jumbo_alloc);
299
300 zone_jumbo16 = uma_zcreate(MBUF_JUMBO16_MEM_NAME, MJUM16BYTES,
301 mb_ctor_clust, mb_dtor_clust,
302 #ifdef INVARIANTS
303 trash_init, trash_fini,
304 #else
305 NULL, NULL,
306 #endif
307 UMA_ALIGN_PTR, UMA_ZONE_REFCNT);
308 if (nmbjumbo16 > 0)
309 uma_zone_set_max(zone_jumbo16, nmbjumbo16);
310 uma_zone_set_allocf(zone_jumbo16, mbuf_jumbo_alloc);
311
312 zone_ext_refcnt = uma_zcreate(MBUF_EXTREFCNT_MEM_NAME, sizeof(u_int),
313 NULL, NULL,
314 NULL, NULL,
315 UMA_ALIGN_PTR, UMA_ZONE_ZINIT);
316
317 /* uma_prealloc() goes here... */
318
319 /*
320 * Hook event handler for low-memory situation, used to
321 * drain protocols and push data back to the caches (UMA
322 * later pushes it back to VM).
323 */
324 EVENTHANDLER_REGISTER(vm_lowmem, mb_reclaim, NULL,
325 EVENTHANDLER_PRI_FIRST);
326
327 /*
328 * [Re]set counters and local statistics knobs.
329 * XXX Some of these should go and be replaced, but UMA stat
330 * gathering needs to be revised.
331 */
332 mbstat.m_mbufs = 0;
333 mbstat.m_mclusts = 0;
334 mbstat.m_drain = 0;
335 mbstat.m_msize = MSIZE;
336 mbstat.m_mclbytes = MCLBYTES;
337 mbstat.m_minclsize = MINCLSIZE;
338 mbstat.m_mlen = MLEN;
339 mbstat.m_mhlen = MHLEN;
340 mbstat.m_numtypes = MT_NTYPES;
341
342 mbstat.m_mcfail = mbstat.m_mpfail = 0;
343 mbstat.sf_iocnt = 0;
344 mbstat.sf_allocwait = mbstat.sf_allocfail = 0;
345 }
346
347 /*
348 * UMA backend page allocator for the jumbo frame zones.
349 *
350 * Allocates kernel virtual memory that is backed by contiguous physical
351 * pages.
352 */
353 static void *
354 mbuf_jumbo_alloc(uma_zone_t zone, int bytes, u_int8_t *flags, int wait)
355 {
356
357 /* Inform UMA that this allocator uses kernel_map/object. */
358 *flags = UMA_SLAB_KERNEL;
359 return ((void *)kmem_alloc_contig(kernel_map, bytes, wait,
360 (vm_paddr_t)0, ~(vm_paddr_t)0, 1, 0, VM_MEMATTR_DEFAULT));
361 }
362
363 /*
364 * Constructor for Mbuf master zone.
365 *
366 * The 'arg' pointer points to a mb_args structure which
367 * contains call-specific information required to support the
368 * mbuf allocation API. See mbuf.h.
369 */
370 static int
371 mb_ctor_mbuf(void *mem, int size, void *arg, int how)
372 {
373 struct mbuf *m;
374 struct mb_args *args;
375 #ifdef MAC
376 int error;
377 #endif
378 int flags;
379 short type;
380
381 #ifdef INVARIANTS
382 trash_ctor(mem, size, arg, how);
383 #endif
384 m = (struct mbuf *)mem;
385 args = (struct mb_args *)arg;
386 flags = args->flags;
387 type = args->type;
388
389 /*
390 * The mbuf is initialized later. The caller has the
391 * responsibility to set up any MAC labels too.
392 */
393 if (type == MT_NOINIT)
394 return (0);
395
396 m->m_next = NULL;
397 m->m_nextpkt = NULL;
398 m->m_len = 0;
399 m->m_flags = flags;
400 m->m_type = type;
401 if (flags & M_PKTHDR) {
402 m->m_data = m->m_pktdat;
403 m->m_pkthdr.rcvif = NULL;
404 m->m_pkthdr.len = 0;
405 m->m_pkthdr.header = NULL;
406 m->m_pkthdr.csum_flags = 0;
407 m->m_pkthdr.csum_data = 0;
408 m->m_pkthdr.tso_segsz = 0;
409 m->m_pkthdr.ether_vtag = 0;
410 SLIST_INIT(&m->m_pkthdr.tags);
411 #ifdef MAC
412 /* If the label init fails, fail the alloc */
413 error = mac_init_mbuf(m, how);
414 if (error)
415 return (error);
416 #endif
417 } else
418 m->m_data = m->m_dat;
419 return (0);
420 }
421
422 /*
423 * The Mbuf master zone destructor.
424 */
425 static void
426 mb_dtor_mbuf(void *mem, int size, void *arg)
427 {
428 struct mbuf *m;
429 unsigned long flags;
430
431 m = (struct mbuf *)mem;
432 flags = (unsigned long)arg;
433
434 if ((flags & MB_NOTAGS) == 0 && (m->m_flags & M_PKTHDR) != 0)
435 m_tag_delete_chain(m, NULL);
436 KASSERT((m->m_flags & M_EXT) == 0, ("%s: M_EXT set", __func__));
437 KASSERT((m->m_flags & M_NOFREE) == 0, ("%s: M_NOFREE set", __func__));
438 #ifdef INVARIANTS
439 trash_dtor(mem, size, arg);
440 #endif
441 }
442
443 /*
444 * The Mbuf Packet zone destructor.
445 */
446 static void
447 mb_dtor_pack(void *mem, int size, void *arg)
448 {
449 struct mbuf *m;
450
451 m = (struct mbuf *)mem;
452 if ((m->m_flags & M_PKTHDR) != 0)
453 m_tag_delete_chain(m, NULL);
454
455 /* Make sure we've got a clean cluster back. */
456 KASSERT((m->m_flags & M_EXT) == M_EXT, ("%s: M_EXT not set", __func__));
457 KASSERT(m->m_ext.ext_buf != NULL, ("%s: ext_buf == NULL", __func__));
458 KASSERT(m->m_ext.ext_free == NULL, ("%s: ext_free != NULL", __func__));
459 KASSERT(m->m_ext.ext_args == NULL, ("%s: ext_args != NULL", __func__));
460 KASSERT(m->m_ext.ext_size == MCLBYTES, ("%s: ext_size != MCLBYTES", __func__));
461 KASSERT(m->m_ext.ext_type == EXT_PACKET, ("%s: ext_type != EXT_PACKET", __func__));
462 KASSERT(*m->m_ext.ref_cnt == 1, ("%s: ref_cnt != 1", __func__));
463 #ifdef INVARIANTS
464 trash_dtor(m->m_ext.ext_buf, MCLBYTES, arg);
465 #endif
466 /*
467 * If there are processes blocked on zone_clust, waiting for pages to be freed up,
468 * cause them to be woken up by draining the packet zone. We are exposed to a race here
469 * (in the check for the UMA_ZFLAG_FULL) where we might miss the flag set, but that is
470 * deliberate. We don't want to acquire the zone lock for every mbuf free.
471 */
472 if (uma_zone_exhausted_nolock(zone_clust))
473 zone_drain(zone_pack);
474 }
475
476 /*
477 * The Cluster and Jumbo[PAGESIZE|9|16] zone constructor.
478 *
479 * Here the 'arg' pointer points to the Mbuf which we
480 * are configuring cluster storage for. If 'arg' is
481 * empty we allocate just the cluster without setting
482 * the mbuf to it. See mbuf.h.
483 */
484 static int
485 mb_ctor_clust(void *mem, int size, void *arg, int how)
486 {
487 struct mbuf *m;
488 u_int *refcnt;
489 int type;
490 uma_zone_t zone;
491
492 #ifdef INVARIANTS
493 trash_ctor(mem, size, arg, how);
494 #endif
495 switch (size) {
496 case MCLBYTES:
497 type = EXT_CLUSTER;
498 zone = zone_clust;
499 break;
500 #if MJUMPAGESIZE != MCLBYTES
501 case MJUMPAGESIZE:
502 type = EXT_JUMBOP;
503 zone = zone_jumbop;
504 break;
505 #endif
506 case MJUM9BYTES:
507 type = EXT_JUMBO9;
508 zone = zone_jumbo9;
509 break;
510 case MJUM16BYTES:
511 type = EXT_JUMBO16;
512 zone = zone_jumbo16;
513 break;
514 default:
515 panic("unknown cluster size");
516 break;
517 }
518
519 m = (struct mbuf *)arg;
520 refcnt = uma_find_refcnt(zone, mem);
521 *refcnt = 1;
522 if (m != NULL) {
523 m->m_ext.ext_buf = (caddr_t)mem;
524 m->m_data = m->m_ext.ext_buf;
525 m->m_flags |= M_EXT;
526 m->m_ext.ext_free = NULL;
527 m->m_ext.ext_args = NULL;
528 m->m_ext.ext_size = size;
529 m->m_ext.ext_type = type;
530 m->m_ext.ref_cnt = refcnt;
531 }
532
533 return (0);
534 }
535
536 /*
537 * The Mbuf Cluster zone destructor.
538 */
539 static void
540 mb_dtor_clust(void *mem, int size, void *arg)
541 {
542 #ifdef INVARIANTS
543 uma_zone_t zone;
544
545 zone = m_getzone(size);
546 KASSERT(*(uma_find_refcnt(zone, mem)) <= 1,
547 ("%s: refcnt incorrect %u", __func__,
548 *(uma_find_refcnt(zone, mem))) );
549
550 trash_dtor(mem, size, arg);
551 #endif
552 }
553
554 /*
555 * The Packet secondary zone's init routine, executed on the
556 * object's transition from mbuf keg slab to zone cache.
557 */
558 static int
559 mb_zinit_pack(void *mem, int size, int how)
560 {
561 struct mbuf *m;
562
563 m = (struct mbuf *)mem; /* m is virgin. */
564 if (uma_zalloc_arg(zone_clust, m, how) == NULL ||
565 m->m_ext.ext_buf == NULL)
566 return (ENOMEM);
567 m->m_ext.ext_type = EXT_PACKET; /* Override. */
568 #ifdef INVARIANTS
569 trash_init(m->m_ext.ext_buf, MCLBYTES, how);
570 #endif
571 return (0);
572 }
573
574 /*
575 * The Packet secondary zone's fini routine, executed on the
576 * object's transition from zone cache to keg slab.
577 */
578 static void
579 mb_zfini_pack(void *mem, int size)
580 {
581 struct mbuf *m;
582
583 m = (struct mbuf *)mem;
584 #ifdef INVARIANTS
585 trash_fini(m->m_ext.ext_buf, MCLBYTES);
586 #endif
587 uma_zfree_arg(zone_clust, m->m_ext.ext_buf, NULL);
588 #ifdef INVARIANTS
589 trash_dtor(mem, size, NULL);
590 #endif
591 }
592
593 /*
594 * The "packet" keg constructor.
595 */
596 static int
597 mb_ctor_pack(void *mem, int size, void *arg, int how)
598 {
599 struct mbuf *m;
600 struct mb_args *args;
601 #ifdef MAC
602 int error;
603 #endif
604 int flags;
605 short type;
606
607 m = (struct mbuf *)mem;
608 args = (struct mb_args *)arg;
609 flags = args->flags;
610 type = args->type;
611
612 #ifdef INVARIANTS
613 trash_ctor(m->m_ext.ext_buf, MCLBYTES, arg, how);
614 #endif
615 m->m_next = NULL;
616 m->m_nextpkt = NULL;
617 m->m_data = m->m_ext.ext_buf;
618 m->m_len = 0;
619 m->m_flags = (flags | M_EXT);
620 m->m_type = type;
621
622 if (flags & M_PKTHDR) {
623 m->m_pkthdr.rcvif = NULL;
624 m->m_pkthdr.len = 0;
625 m->m_pkthdr.header = NULL;
626 m->m_pkthdr.csum_flags = 0;
627 m->m_pkthdr.csum_data = 0;
628 m->m_pkthdr.tso_segsz = 0;
629 m->m_pkthdr.ether_vtag = 0;
630 SLIST_INIT(&m->m_pkthdr.tags);
631 #ifdef MAC
632 /* If the label init fails, fail the alloc */
633 error = mac_init_mbuf(m, how);
634 if (error)
635 return (error);
636 #endif
637 }
638 /* m_ext is already initialized. */
639
640 return (0);
641 }
642
643 /*
644 * This is the protocol drain routine.
645 *
646 * No locks should be held when this is called. The drain routines have to
647 * presently acquire some locks which raises the possibility of lock order
648 * reversal.
649 */
650 static void
651 mb_reclaim(void *junk)
652 {
653 struct domain *dp;
654 struct protosw *pr;
655
656 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK | WARN_PANIC, NULL,
657 "mb_reclaim()");
658
659 for (dp = domains; dp != NULL; dp = dp->dom_next)
660 for (pr = dp->dom_protosw; pr < dp->dom_protoswNPROTOSW; pr++)
661 if (pr->pr_drain != NULL)
662 (*pr->pr_drain)();
663 }
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