#include <machine/rtems-bsd-kernel-space.h>
/*-
* Copyright (c) 2004, 2005,
* Bosko Milekic <bmilekic@FreeBSD.org>. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice unmodified, this list of conditions and the following
* disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <rtems/bsd/local/opt_param.h>
#include <rtems/bsd/sys/param.h>
#include <sys/malloc.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <sys/domain.h>
#include <sys/eventhandler.h>
#include <sys/kernel.h>
#include <sys/protosw.h>
#include <sys/smp.h>
#include <sys/sysctl.h>
#include <security/mac/mac_framework.h>
#include <vm/vm.h>
#include <vm/vm_extern.h>
#include <vm/vm_kern.h>
#include <vm/vm_page.h>
#include <vm/uma.h>
#include <vm/uma_int.h>
#include <vm/uma_dbg.h>
/*
* In FreeBSD, Mbufs and Mbuf Clusters are allocated from UMA
* Zones.
*
* Mbuf Clusters (2K, contiguous) are allocated from the Cluster
* Zone. The Zone can be capped at kern.ipc.nmbclusters, if the
* administrator so desires.
*
* Mbufs are allocated from a UMA Master Zone called the Mbuf
* Zone.
*
* Additionally, FreeBSD provides a Packet Zone, which it
* configures as a Secondary Zone to the Mbuf Master Zone,
* thus sharing backend Slab kegs with the Mbuf Master Zone.
*
* Thus common-case allocations and locking are simplified:
*
* m_clget() m_getcl()
* | |
* | .------------>[(Packet Cache)] m_get(), m_gethdr()
* | | [ Packet ] |
* [(Cluster Cache)] [ Secondary ] [ (Mbuf Cache) ]
* [ Cluster Zone ] [ Zone ] [ Mbuf Master Zone ]
* | \________ |
* [ Cluster Keg ] \ /
* | [ Mbuf Keg ]
* [ Cluster Slabs ] |
* | [ Mbuf Slabs ]
* \____________(VM)_________________/
*
*
* Whenever an object is allocated with uma_zalloc() out of
* one of the Zones its _ctor_ function is executed. The same
* for any deallocation through uma_zfree() the _dtor_ function
* is executed.
*
* Caches are per-CPU and are filled from the Master Zone.
*
* Whenever an object is allocated from the underlying global
* memory pool it gets pre-initialized with the _zinit_ functions.
* When the Keg's are overfull objects get decomissioned with
* _zfini_ functions and free'd back to the global memory pool.
*
*/
int nmbclusters; /* limits number of mbuf clusters */
int nmbjumbop; /* limits number of page size jumbo clusters */
int nmbjumbo9; /* limits number of 9k jumbo clusters */
int nmbjumbo16; /* limits number of 16k jumbo clusters */
struct mbstat mbstat;
/*
* tunable_mbinit() has to be run before init_maxsockets() thus
* the SYSINIT order below is SI_ORDER_MIDDLE while init_maxsockets()
* runs at SI_ORDER_ANY.
*/
static void
tunable_mbinit(void *dummy)
{
/* This has to be done before VM init. */
TUNABLE_INT_FETCH("kern.ipc.nmbclusters", &nmbclusters);
if (nmbclusters == 0)
nmbclusters = 1024 + maxusers * 64;
TUNABLE_INT_FETCH("kern.ipc.nmbjumbop", &nmbjumbop);
if (nmbjumbop == 0)
nmbjumbop = nmbclusters / 2;
TUNABLE_INT_FETCH("kern.ipc.nmbjumbo9", &nmbjumbo9);
if (nmbjumbo9 == 0)
nmbjumbo9 = nmbclusters / 4;
TUNABLE_INT_FETCH("kern.ipc.nmbjumbo16", &nmbjumbo16);
if (nmbjumbo16 == 0)
nmbjumbo16 = nmbclusters / 8;
}
SYSINIT(tunable_mbinit, SI_SUB_TUNABLES, SI_ORDER_MIDDLE, tunable_mbinit, NULL);
static int
sysctl_nmbclusters(SYSCTL_HANDLER_ARGS)
{
int error, newnmbclusters;
newnmbclusters = nmbclusters;
error = sysctl_handle_int(oidp, &newnmbclusters, 0, req);
if (error == 0 && req->newptr) {
if (newnmbclusters > nmbclusters) {
nmbclusters = newnmbclusters;
uma_zone_set_max(zone_clust, nmbclusters);
#ifndef __rtems__
EVENTHANDLER_INVOKE(nmbclusters_change);
#endif /* __rtems__ */
} else
error = EINVAL;
}
return (error);
}
SYSCTL_PROC(_kern_ipc, OID_AUTO, nmbclusters, CTLTYPE_INT|CTLFLAG_RW,
&nmbclusters, 0, sysctl_nmbclusters, "IU",
"Maximum number of mbuf clusters allowed");
static int
sysctl_nmbjumbop(SYSCTL_HANDLER_ARGS)
{
int error, newnmbjumbop;
newnmbjumbop = nmbjumbop;
error = sysctl_handle_int(oidp, &newnmbjumbop, 0, req);
if (error == 0 && req->newptr) {
if (newnmbjumbop> nmbjumbop) {
nmbjumbop = newnmbjumbop;
uma_zone_set_max(zone_jumbop, nmbjumbop);
} else
error = EINVAL;
}
return (error);
}
SYSCTL_PROC(_kern_ipc, OID_AUTO, nmbjumbop, CTLTYPE_INT|CTLFLAG_RW,
&nmbjumbop, 0, sysctl_nmbjumbop, "IU",
"Maximum number of mbuf page size jumbo clusters allowed");
static int
sysctl_nmbjumbo9(SYSCTL_HANDLER_ARGS)
{
int error, newnmbjumbo9;
newnmbjumbo9 = nmbjumbo9;
error = sysctl_handle_int(oidp, &newnmbjumbo9, 0, req);
if (error == 0 && req->newptr) {
if (newnmbjumbo9> nmbjumbo9) {
nmbjumbo9 = newnmbjumbo9;
uma_zone_set_max(zone_jumbo9, nmbjumbo9);
} else
error = EINVAL;
}
return (error);
}
SYSCTL_PROC(_kern_ipc, OID_AUTO, nmbjumbo9, CTLTYPE_INT|CTLFLAG_RW,
&nmbjumbo9, 0, sysctl_nmbjumbo9, "IU",
"Maximum number of mbuf 9k jumbo clusters allowed");
static int
sysctl_nmbjumbo16(SYSCTL_HANDLER_ARGS)
{
int error, newnmbjumbo16;
newnmbjumbo16 = nmbjumbo16;
error = sysctl_handle_int(oidp, &newnmbjumbo16, 0, req);
if (error == 0 && req->newptr) {
if (newnmbjumbo16> nmbjumbo16) {
nmbjumbo16 = newnmbjumbo16;
uma_zone_set_max(zone_jumbo16, nmbjumbo16);
} else
error = EINVAL;
}
return (error);
}
SYSCTL_PROC(_kern_ipc, OID_AUTO, nmbjumbo16, CTLTYPE_INT|CTLFLAG_RW,
&nmbjumbo16, 0, sysctl_nmbjumbo16, "IU",
"Maximum number of mbuf 16k jumbo clusters allowed");
SYSCTL_STRUCT(_kern_ipc, OID_AUTO, mbstat, CTLFLAG_RD, &mbstat, mbstat,
"Mbuf general information and statistics");
/*
* Zones from which we allocate.
*/
uma_zone_t zone_mbuf;
uma_zone_t zone_clust;
uma_zone_t zone_pack;
uma_zone_t zone_jumbop;
uma_zone_t zone_jumbo9;
uma_zone_t zone_jumbo16;
uma_zone_t zone_ext_refcnt;
/*
* Local prototypes.
*/
static int mb_ctor_mbuf(void *, int, void *, int);
static int mb_ctor_clust(void *, int, void *, int);
static int mb_ctor_pack(void *, int, void *, int);
static void mb_dtor_mbuf(void *, int, void *);
static void mb_dtor_clust(void *, int, void *);
static void mb_dtor_pack(void *, int, void *);
static int mb_zinit_pack(void *, int, int);
static void mb_zfini_pack(void *, int);
static void mb_reclaim(void *);
static void mbuf_init(void *);
static void *mbuf_jumbo_alloc(uma_zone_t, int, uint8_t *, int);
/* Ensure that MSIZE doesn't break dtom() - it must be a power of 2 */
CTASSERT((((MSIZE - 1) ^ MSIZE) + 1) >> 1 == MSIZE);
/*
* Initialize FreeBSD Network buffer allocation.
*/
SYSINIT(mbuf, SI_SUB_MBUF, SI_ORDER_FIRST, mbuf_init, NULL);
static void
mbuf_init(void *dummy)
{
/*
* Configure UMA zones for Mbufs, Clusters, and Packets.
*/
zone_mbuf = uma_zcreate(MBUF_MEM_NAME, MSIZE,
mb_ctor_mbuf, mb_dtor_mbuf,
#ifdef INVARIANTS
trash_init, trash_fini,
#else
NULL, NULL,
#endif
MSIZE - 1, UMA_ZONE_MAXBUCKET);
zone_clust = uma_zcreate(MBUF_CLUSTER_MEM_NAME, MCLBYTES,
mb_ctor_clust, mb_dtor_clust,
#ifdef INVARIANTS
trash_init, trash_fini,
#else
NULL, NULL,
#endif
UMA_ALIGN_PTR, UMA_ZONE_REFCNT);
if (nmbclusters > 0)
uma_zone_set_max(zone_clust, nmbclusters);
zone_pack = uma_zsecond_create(MBUF_PACKET_MEM_NAME, mb_ctor_pack,
mb_dtor_pack, mb_zinit_pack, mb_zfini_pack, zone_mbuf);
/* Make jumbo frame zone too. Page size, 9k and 16k. */
zone_jumbop = uma_zcreate(MBUF_JUMBOP_MEM_NAME, MJUMPAGESIZE,
mb_ctor_clust, mb_dtor_clust,
#ifdef INVARIANTS
trash_init, trash_fini,
#else
NULL, NULL,
#endif
UMA_ALIGN_PTR, UMA_ZONE_REFCNT);
if (nmbjumbop > 0)
uma_zone_set_max(zone_jumbop, nmbjumbop);
zone_jumbo9 = uma_zcreate(MBUF_JUMBO9_MEM_NAME, MJUM9BYTES,
mb_ctor_clust, mb_dtor_clust,
#ifdef INVARIANTS
trash_init, trash_fini,
#else
NULL, NULL,
#endif
UMA_ALIGN_PTR, UMA_ZONE_REFCNT);
if (nmbjumbo9 > 0)
uma_zone_set_max(zone_jumbo9, nmbjumbo9);
uma_zone_set_allocf(zone_jumbo9, mbuf_jumbo_alloc);
zone_jumbo16 = uma_zcreate(MBUF_JUMBO16_MEM_NAME, MJUM16BYTES,
mb_ctor_clust, mb_dtor_clust,
#ifdef INVARIANTS
trash_init, trash_fini,
#else
NULL, NULL,
#endif
UMA_ALIGN_PTR, UMA_ZONE_REFCNT);
if (nmbjumbo16 > 0)
uma_zone_set_max(zone_jumbo16, nmbjumbo16);
uma_zone_set_allocf(zone_jumbo16, mbuf_jumbo_alloc);
zone_ext_refcnt = uma_zcreate(MBUF_EXTREFCNT_MEM_NAME, sizeof(u_int),
NULL, NULL,
NULL, NULL,
UMA_ALIGN_PTR, UMA_ZONE_ZINIT);
/* uma_prealloc() goes here... */
/*
* Hook event handler for low-memory situation, used to
* drain protocols and push data back to the caches (UMA
* later pushes it back to VM).
*/
#ifndef __rtems__
EVENTHANDLER_REGISTER(vm_lowmem, mb_reclaim, NULL,
EVENTHANDLER_PRI_FIRST);
#endif /* __rtems__ */
/*
* [Re]set counters and local statistics knobs.
* XXX Some of these should go and be replaced, but UMA stat
* gathering needs to be revised.
*/
mbstat.m_mbufs = 0;
mbstat.m_mclusts = 0;
mbstat.m_drain = 0;
mbstat.m_msize = MSIZE;
mbstat.m_mclbytes = MCLBYTES;
mbstat.m_minclsize = MINCLSIZE;
mbstat.m_mlen = MLEN;
mbstat.m_mhlen = MHLEN;
mbstat.m_numtypes = MT_NTYPES;
mbstat.m_mcfail = mbstat.m_mpfail = 0;
mbstat.sf_iocnt = 0;
mbstat.sf_allocwait = mbstat.sf_allocfail = 0;
}
/*
* UMA backend page allocator for the jumbo frame zones.
*
* Allocates kernel virtual memory that is backed by contiguous physical
* pages.
*/
static void *
mbuf_jumbo_alloc(uma_zone_t zone, int bytes, uint8_t *flags, int wait)
{
/* Inform UMA that this allocator uses kernel_map/object. */
*flags = UMA_SLAB_KERNEL;
#ifndef __rtems__
return ((void *)kmem_alloc_contig(kernel_map, bytes, wait,
(vm_paddr_t)0, ~(vm_paddr_t)0, 1, 0, VM_MEMATTR_DEFAULT));
#else /* __rtems__ */
return ((void *)malloc(bytes, M_TEMP, wait));
#endif /* __rtems__ */
}
/*
* Constructor for Mbuf master zone.
*
* The 'arg' pointer points to a mb_args structure which
* contains call-specific information required to support the
* mbuf allocation API. See mbuf.h.
*/
static int
mb_ctor_mbuf(void *mem, int size, void *arg, int how)
{
struct mbuf *m;
struct mb_args *args;
#ifdef MAC
int error;
#endif
int flags;
short type;
#ifdef INVARIANTS
trash_ctor(mem, size, arg, how);
#endif
m = (struct mbuf *)mem;
args = (struct mb_args *)arg;
flags = args->flags;
type = args->type;
/*
* The mbuf is initialized later. The caller has the
* responsibility to set up any MAC labels too.
*/
if (type == MT_NOINIT)
return (0);
m->m_next = NULL;
m->m_nextpkt = NULL;
m->m_len = 0;
m->m_flags = flags;
m->m_type = type;
if (flags & M_PKTHDR) {
m->m_data = m->m_pktdat;
m->m_pkthdr.rcvif = NULL;
m->m_pkthdr.header = NULL;
m->m_pkthdr.len = 0;
m->m_pkthdr.csum_flags = 0;
m->m_pkthdr.csum_data = 0;
m->m_pkthdr.tso_segsz = 0;
m->m_pkthdr.ether_vtag = 0;
m->m_pkthdr.flowid = 0;
SLIST_INIT(&m->m_pkthdr.tags);
#ifdef MAC
/* If the label init fails, fail the alloc */
error = mac_mbuf_init(m, how);
if (error)
return (error);
#endif
} else
m->m_data = m->m_dat;
return (0);
}
/*
* The Mbuf master zone destructor.
*/
static void
mb_dtor_mbuf(void *mem, int size, void *arg)
{
struct mbuf *m;
unsigned long flags;
m = (struct mbuf *)mem;
flags = (unsigned long)arg;
if ((flags & MB_NOTAGS) == 0 && (m->m_flags & M_PKTHDR) != 0)
m_tag_delete_chain(m, NULL);
KASSERT((m->m_flags & M_EXT) == 0, ("%s: M_EXT set", __func__));
KASSERT((m->m_flags & M_NOFREE) == 0, ("%s: M_NOFREE set", __func__));
#ifdef INVARIANTS
trash_dtor(mem, size, arg);
#endif
}
/*
* The Mbuf Packet zone destructor.
*/
static void
mb_dtor_pack(void *mem, int size, void *arg)
{
struct mbuf *m;
m = (struct mbuf *)mem;
if ((m->m_flags & M_PKTHDR) != 0)
m_tag_delete_chain(m, NULL);
/* Make sure we've got a clean cluster back. */
KASSERT((m->m_flags & M_EXT) == M_EXT, ("%s: M_EXT not set", __func__));
KASSERT(m->m_ext.ext_buf != NULL, ("%s: ext_buf == NULL", __func__));
KASSERT(m->m_ext.ext_free == NULL, ("%s: ext_free != NULL", __func__));
KASSERT(m->m_ext.ext_arg1 == NULL, ("%s: ext_arg1 != NULL", __func__));
KASSERT(m->m_ext.ext_arg2 == NULL, ("%s: ext_arg2 != NULL", __func__));
KASSERT(m->m_ext.ext_size == MCLBYTES, ("%s: ext_size != MCLBYTES", __func__));
KASSERT(m->m_ext.ext_type == EXT_PACKET, ("%s: ext_type != EXT_PACKET", __func__));
KASSERT(*m->m_ext.ref_cnt == 1, ("%s: ref_cnt != 1", __func__));
#ifdef INVARIANTS
trash_dtor(m->m_ext.ext_buf, MCLBYTES, arg);
#endif
/*
* If there are processes blocked on zone_clust, waiting for pages
* to be freed up, * cause them to be woken up by draining the
* packet zone. We are exposed to a race here * (in the check for
* the UMA_ZFLAG_FULL) where we might miss the flag set, but that
* is deliberate. We don't want to acquire the zone lock for every
* mbuf free.
*/
if (uma_zone_exhausted_nolock(zone_clust))
zone_drain(zone_pack);
}
/*
* The Cluster and Jumbo[PAGESIZE|9|16] zone constructor.
*
* Here the 'arg' pointer points to the Mbuf which we
* are configuring cluster storage for. If 'arg' is
* empty we allocate just the cluster without setting
* the mbuf to it. See mbuf.h.
*/
static int
mb_ctor_clust(void *mem, int size, void *arg, int how)
{
struct mbuf *m;
u_int *refcnt;
int type;
uma_zone_t zone;
#ifdef INVARIANTS
trash_ctor(mem, size, arg, how);
#endif
switch (size) {
case MCLBYTES:
type = EXT_CLUSTER;
zone = zone_clust;
break;
#if MJUMPAGESIZE != MCLBYTES
case MJUMPAGESIZE:
type = EXT_JUMBOP;
zone = zone_jumbop;
break;
#endif
case MJUM9BYTES:
type = EXT_JUMBO9;
zone = zone_jumbo9;
break;
case MJUM16BYTES:
type = EXT_JUMBO16;
zone = zone_jumbo16;
break;
default:
panic("unknown cluster size");
break;
}
m = (struct mbuf *)arg;
refcnt = uma_find_refcnt(zone, mem);
*refcnt = 1;
if (m != NULL) {
m->m_ext.ext_buf = (caddr_t)mem;
m->m_data = m->m_ext.ext_buf;
m->m_flags |= M_EXT;
m->m_ext.ext_free = NULL;
m->m_ext.ext_arg1 = NULL;
m->m_ext.ext_arg2 = NULL;
m->m_ext.ext_size = size;
m->m_ext.ext_type = type;
m->m_ext.ref_cnt = refcnt;
}
return (0);
}
/*
* The Mbuf Cluster zone destructor.
*/
static void
mb_dtor_clust(void *mem, int size, void *arg)
{
#ifdef INVARIANTS
uma_zone_t zone;
zone = m_getzone(size);
KASSERT(*(uma_find_refcnt(zone, mem)) <= 1,
("%s: refcnt incorrect %u", __func__,
*(uma_find_refcnt(zone, mem))) );
trash_dtor(mem, size, arg);
#endif
}
/*
* The Packet secondary zone's init routine, executed on the
* object's transition from mbuf keg slab to zone cache.
*/
static int
mb_zinit_pack(void *mem, int size, int how)
{
struct mbuf *m;
m = (struct mbuf *)mem; /* m is virgin. */
if (uma_zalloc_arg(zone_clust, m, how) == NULL ||
m->m_ext.ext_buf == NULL)
return (ENOMEM);
m->m_ext.ext_type = EXT_PACKET; /* Override. */
#ifdef INVARIANTS
trash_init(m->m_ext.ext_buf, MCLBYTES, how);
#endif
return (0);
}
/*
* The Packet secondary zone's fini routine, executed on the
* object's transition from zone cache to keg slab.
*/
static void
mb_zfini_pack(void *mem, int size)
{
struct mbuf *m;
m = (struct mbuf *)mem;
#ifdef INVARIANTS
trash_fini(m->m_ext.ext_buf, MCLBYTES);
#endif
uma_zfree_arg(zone_clust, m->m_ext.ext_buf, NULL);
#ifdef INVARIANTS
trash_dtor(mem, size, NULL);
#endif
}
/*
* The "packet" keg constructor.
*/
static int
mb_ctor_pack(void *mem, int size, void *arg, int how)
{
struct mbuf *m;
struct mb_args *args;
#ifdef MAC
int error;
#endif
int flags;
short type;
m = (struct mbuf *)mem;
args = (struct mb_args *)arg;
flags = args->flags;
type = args->type;
#ifdef INVARIANTS
trash_ctor(m->m_ext.ext_buf, MCLBYTES, arg, how);
#endif
m->m_next = NULL;
m->m_nextpkt = NULL;
m->m_data = m->m_ext.ext_buf;
m->m_len = 0;
m->m_flags = (flags | M_EXT);
m->m_type = type;
if (flags & M_PKTHDR) {
m->m_pkthdr.rcvif = NULL;
m->m_pkthdr.len = 0;
m->m_pkthdr.header = NULL;
m->m_pkthdr.csum_flags = 0;
m->m_pkthdr.csum_data = 0;
m->m_pkthdr.tso_segsz = 0;
m->m_pkthdr.ether_vtag = 0;
m->m_pkthdr.flowid = 0;
SLIST_INIT(&m->m_pkthdr.tags);
#ifdef MAC
/* If the label init fails, fail the alloc */
error = mac_mbuf_init(m, how);
if (error)
return (error);
#endif
}
/* m_ext is already initialized. */
return (0);
}
int
m_pkthdr_init(struct mbuf *m, int how)
{
#ifdef MAC
int error;
#endif
m->m_data = m->m_pktdat;
SLIST_INIT(&m->m_pkthdr.tags);
m->m_pkthdr.rcvif = NULL;
m->m_pkthdr.header = NULL;
m->m_pkthdr.len = 0;
m->m_pkthdr.flowid = 0;
m->m_pkthdr.csum_flags = 0;
m->m_pkthdr.csum_data = 0;
m->m_pkthdr.tso_segsz = 0;
m->m_pkthdr.ether_vtag = 0;
#ifdef MAC
/* If the label init fails, fail the alloc */
error = mac_mbuf_init(m, how);
if (error)
return (error);
#endif
return (0);
}
/*
* This is the protocol drain routine.
*
* No locks should be held when this is called. The drain routines have to
* presently acquire some locks which raises the possibility of lock order
* reversal.
*/
static void
mb_reclaim(void *junk)
{
struct domain *dp;
struct protosw *pr;
WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK | WARN_PANIC, NULL,
"mb_reclaim()");
for (dp = domains; dp != NULL; dp = dp->dom_next)
for (pr = dp->dom_protosw; pr < dp->dom_protoswNPROTOSW; pr++)
if (pr->pr_drain != NULL)
(*pr->pr_drain)();
}
