freebsd-skq/sys/kern/subr_eventhandler.c
bz 102a1f8933 Split eventhandler_register() into an internal part and a wrapper function
that provides the allocated and setup eventhandler entry.

Add a new wrapper for VIMAGE that allocates extra space to hold the
callback function and argument in addition to an extra wrapper function.
While the wrapper function goes as normal callback function the
argument points to the extra space allocated holding the original func
and arg that the wrapper function can then call.

Provide an iterator function for the virtual network stack (vnet) that
will call the callback function for each network stack.

Provide a new set of macros for VNET that in the non-VIMAGE case will
just call eventhandler_register() while in the VIMAGE case it will use
vimage_eventhandler_register() passing in the extra iterator function
but will only register once rather than per-vnet.
We need a special macro in case we are interested in the tag returned
as we must check for curvnet and can neither simply assign the
return value, nor not change it in the non-vnet0 case without that.

Sponsored by:	ISPsystem
Discussed with:	jhb
Reviewed by:	zec (earlier version), jhb
MFC after:	1 month
2010-03-19 19:51:03 +00:00

281 lines
8.5 KiB
C

/*-
* Copyright (c) 1999 Michael Smith <msmith@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, 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 <sys/param.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/systm.h>
#include <sys/eventhandler.h>
static MALLOC_DEFINE(M_EVENTHANDLER, "eventhandler", "Event handler records");
/* List of 'slow' lists */
static TAILQ_HEAD(, eventhandler_list) eventhandler_lists;
static int eventhandler_lists_initted = 0;
static struct mtx eventhandler_mutex;
struct eventhandler_entry_generic
{
struct eventhandler_entry ee;
void (* func)(void);
};
static struct eventhandler_list *_eventhandler_find_list(const char *name);
/*
* Initialize the eventhandler mutex and list.
*/
static void
eventhandler_init(void *dummy __unused)
{
TAILQ_INIT(&eventhandler_lists);
mtx_init(&eventhandler_mutex, "eventhandler", NULL, MTX_DEF);
atomic_store_rel_int(&eventhandler_lists_initted, 1);
}
SYSINIT(eventhandlers, SI_SUB_EVENTHANDLER, SI_ORDER_FIRST, eventhandler_init,
NULL);
/*
* Insertion is O(n) due to the priority scan, but optimises to O(1)
* if all priorities are identical.
*/
static eventhandler_tag
eventhandler_register_internal(struct eventhandler_list *list,
const char *name, eventhandler_tag epn)
{
struct eventhandler_list *new_list;
struct eventhandler_entry *ep;
KASSERT(eventhandler_lists_initted, ("eventhandler registered too early"));
KASSERT(epn != NULL, ("%s: cannot register NULL event", __func__));
/* lock the eventhandler lists */
mtx_lock(&eventhandler_mutex);
/* Do we need to find/create the (slow) list? */
if (list == NULL) {
/* look for a matching, existing list */
list = _eventhandler_find_list(name);
/* Do we need to create the list? */
if (list == NULL) {
mtx_unlock(&eventhandler_mutex);
new_list = malloc(sizeof(struct eventhandler_list) +
strlen(name) + 1, M_EVENTHANDLER, M_WAITOK);
/* If someone else created it already, then use that one. */
mtx_lock(&eventhandler_mutex);
list = _eventhandler_find_list(name);
if (list != NULL) {
free(new_list, M_EVENTHANDLER);
} else {
CTR2(KTR_EVH, "%s: creating list \"%s\"", __func__, name);
list = new_list;
list->el_flags = 0;
list->el_runcount = 0;
bzero(&list->el_lock, sizeof(list->el_lock));
list->el_name = (char *)list + sizeof(struct eventhandler_list);
strcpy(list->el_name, name);
TAILQ_INSERT_HEAD(&eventhandler_lists, list, el_link);
}
}
}
if (!(list->el_flags & EHL_INITTED)) {
TAILQ_INIT(&list->el_entries);
mtx_init(&list->el_lock, name, "eventhandler list", MTX_DEF);
atomic_store_rel_int(&list->el_flags, EHL_INITTED);
}
mtx_unlock(&eventhandler_mutex);
KASSERT(epn->ee_priority != EHE_DEAD_PRIORITY,
("%s: handler for %s registered with dead priority", __func__, name));
/* sort it into the list */
CTR4(KTR_EVH, "%s: adding item %p (function %p) to \"%s\"", __func__, epn,
((struct eventhandler_entry_generic *)epn)->func, name);
EHL_LOCK(list);
TAILQ_FOREACH(ep, &list->el_entries, ee_link) {
if (ep->ee_priority != EHE_DEAD_PRIORITY &&
epn->ee_priority < ep->ee_priority) {
TAILQ_INSERT_BEFORE(ep, epn, ee_link);
break;
}
}
if (ep == NULL)
TAILQ_INSERT_TAIL(&list->el_entries, epn, ee_link);
EHL_UNLOCK(list);
return(epn);
}
eventhandler_tag
eventhandler_register(struct eventhandler_list *list, const char *name,
void *func, void *arg, int priority)
{
struct eventhandler_entry_generic *eg;
/* allocate an entry for this handler, populate it */
eg = malloc(sizeof(struct eventhandler_entry_generic), M_EVENTHANDLER,
M_WAITOK | M_ZERO);
eg->func = func;
eg->ee.ee_arg = arg;
eg->ee.ee_priority = priority;
return (eventhandler_register_internal(list, name, &eg->ee));
}
#ifdef VIMAGE
struct eventhandler_entry_generic_vimage
{
struct eventhandler_entry ee;
vimage_iterator_func_t func; /* Vimage iterator function. */
struct eventhandler_entry_vimage v_ee; /* Original func, arg. */
};
eventhandler_tag
vimage_eventhandler_register(struct eventhandler_list *list, const char *name,
void *func, void *arg, int priority, vimage_iterator_func_t iterfunc)
{
struct eventhandler_entry_generic_vimage *eg;
/* allocate an entry for this handler, populate it */
eg = malloc(sizeof(struct eventhandler_entry_generic_vimage),
M_EVENTHANDLER, M_WAITOK | M_ZERO);
eg->func = iterfunc;
eg->v_ee.func = func;
eg->v_ee.ee_arg = arg;
eg->ee.ee_arg = &eg->v_ee;
eg->ee.ee_priority = priority;
return (eventhandler_register_internal(list, name, &eg->ee));
}
#endif
void
eventhandler_deregister(struct eventhandler_list *list, eventhandler_tag tag)
{
struct eventhandler_entry *ep = tag;
EHL_LOCK_ASSERT(list, MA_OWNED);
if (ep != NULL) {
/* remove just this entry */
if (list->el_runcount == 0) {
CTR3(KTR_EVH, "%s: removing item %p from \"%s\"", __func__, ep,
list->el_name);
TAILQ_REMOVE(&list->el_entries, ep, ee_link);
free(ep, M_EVENTHANDLER);
} else {
CTR3(KTR_EVH, "%s: marking item %p from \"%s\" as dead", __func__,
ep, list->el_name);
ep->ee_priority = EHE_DEAD_PRIORITY;
}
} else {
/* remove entire list */
if (list->el_runcount == 0) {
CTR2(KTR_EVH, "%s: removing all items from \"%s\"", __func__,
list->el_name);
while (!TAILQ_EMPTY(&list->el_entries)) {
ep = TAILQ_FIRST(&list->el_entries);
TAILQ_REMOVE(&list->el_entries, ep, ee_link);
free(ep, M_EVENTHANDLER);
}
} else {
CTR2(KTR_EVH, "%s: marking all items from \"%s\" as dead",
__func__, list->el_name);
TAILQ_FOREACH(ep, &list->el_entries, ee_link)
ep->ee_priority = EHE_DEAD_PRIORITY;
}
}
while (list->el_runcount > 0)
mtx_sleep(list, &list->el_lock, 0, "evhrm", 0);
EHL_UNLOCK(list);
}
/*
* Internal version for use when eventhandler list is already locked.
*/
static struct eventhandler_list *
_eventhandler_find_list(const char *name)
{
struct eventhandler_list *list;
mtx_assert(&eventhandler_mutex, MA_OWNED);
TAILQ_FOREACH(list, &eventhandler_lists, el_link) {
if (!strcmp(name, list->el_name))
break;
}
return (list);
}
/*
* Lookup a "slow" list by name. Returns with the list locked.
*/
struct eventhandler_list *
eventhandler_find_list(const char *name)
{
struct eventhandler_list *list;
if (!eventhandler_lists_initted)
return(NULL);
/* scan looking for the requested list */
mtx_lock(&eventhandler_mutex);
list = _eventhandler_find_list(name);
if (list != NULL)
EHL_LOCK(list);
mtx_unlock(&eventhandler_mutex);
return(list);
}
/*
* Prune "dead" entries from an eventhandler list.
*/
void
eventhandler_prune_list(struct eventhandler_list *list)
{
struct eventhandler_entry *ep, *en;
int pruned = 0;
CTR2(KTR_EVH, "%s: pruning list \"%s\"", __func__, list->el_name);
EHL_LOCK_ASSERT(list, MA_OWNED);
TAILQ_FOREACH_SAFE(ep, &list->el_entries, ee_link, en) {
if (ep->ee_priority == EHE_DEAD_PRIORITY) {
TAILQ_REMOVE(&list->el_entries, ep, ee_link);
free(ep, M_EVENTHANDLER);
pruned++;
}
}
if (pruned > 0)
wakeup(list);
}