2b54315009
threads are executing the eventhandler, sleep in this case to make it safe for module unload. If the runcount was up then an entry would have been marked EHE_DEAD_PRIORITY so use this as a trigger to do the wakeup in eventhandler_prune_list(). Reviewed by: jhb
244 lines
7.3 KiB
C
244 lines
7.3 KiB
C
/*-
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* Copyright (c) 1999 Michael Smith <msmith@freebsd.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/kernel.h>
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#include <sys/lock.h>
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#include <sys/malloc.h>
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#include <sys/mutex.h>
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#include <sys/proc.h>
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#include <sys/systm.h>
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#include <sys/eventhandler.h>
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static MALLOC_DEFINE(M_EVENTHANDLER, "eventhandler", "Event handler records");
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/* List of 'slow' lists */
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static TAILQ_HEAD(, eventhandler_list) eventhandler_lists;
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static int eventhandler_lists_initted = 0;
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static struct mtx eventhandler_mutex;
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struct eventhandler_entry_generic
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{
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struct eventhandler_entry ee;
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void (* func)(void);
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};
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static struct eventhandler_list *_eventhandler_find_list(const char *name);
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/*
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* Initialize the eventhandler mutex and list.
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*/
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static void
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eventhandler_init(void *dummy __unused)
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{
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TAILQ_INIT(&eventhandler_lists);
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mtx_init(&eventhandler_mutex, "eventhandler", NULL, MTX_DEF);
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atomic_store_rel_int(&eventhandler_lists_initted, 1);
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}
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SYSINIT(eventhandlers, SI_SUB_EVENTHANDLER, SI_ORDER_FIRST, eventhandler_init,
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NULL);
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/*
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* Insertion is O(n) due to the priority scan, but optimises to O(1)
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* if all priorities are identical.
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*/
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eventhandler_tag
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eventhandler_register(struct eventhandler_list *list, const char *name,
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void *func, void *arg, int priority)
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{
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struct eventhandler_list *new_list;
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struct eventhandler_entry_generic *eg;
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struct eventhandler_entry *ep;
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KASSERT(eventhandler_lists_initted, ("eventhandler registered too early"));
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/* lock the eventhandler lists */
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mtx_lock(&eventhandler_mutex);
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/* Do we need to find/create the (slow) list? */
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if (list == NULL) {
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/* look for a matching, existing list */
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list = _eventhandler_find_list(name);
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/* Do we need to create the list? */
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if (list == NULL) {
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mtx_unlock(&eventhandler_mutex);
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new_list = malloc(sizeof(struct eventhandler_list) +
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strlen(name) + 1, M_EVENTHANDLER, M_WAITOK);
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/* If someone else created it already, then use that one. */
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mtx_lock(&eventhandler_mutex);
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list = _eventhandler_find_list(name);
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if (list != NULL) {
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free(new_list, M_EVENTHANDLER);
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} else {
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CTR2(KTR_EVH, "%s: creating list \"%s\"", __func__, name);
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list = new_list;
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list->el_flags = 0;
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list->el_runcount = 0;
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bzero(&list->el_lock, sizeof(list->el_lock));
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list->el_name = (char *)list + sizeof(struct eventhandler_list);
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strcpy(list->el_name, name);
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TAILQ_INSERT_HEAD(&eventhandler_lists, list, el_link);
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}
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}
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}
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if (!(list->el_flags & EHL_INITTED)) {
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TAILQ_INIT(&list->el_entries);
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mtx_init(&list->el_lock, name, "eventhandler list", MTX_DEF);
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atomic_store_rel_int(&list->el_flags, EHL_INITTED);
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}
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mtx_unlock(&eventhandler_mutex);
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/* allocate an entry for this handler, populate it */
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eg = malloc(sizeof(struct eventhandler_entry_generic), M_EVENTHANDLER,
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M_WAITOK | M_ZERO);
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eg->func = func;
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eg->ee.ee_arg = arg;
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eg->ee.ee_priority = priority;
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KASSERT(priority != EHE_DEAD_PRIORITY,
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("%s: handler for %s registered with dead priority", __func__, name));
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/* sort it into the list */
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CTR4(KTR_EVH, "%s: adding item %p (function %p) to \"%s\"", __func__, eg,
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func, name);
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EHL_LOCK(list);
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TAILQ_FOREACH(ep, &list->el_entries, ee_link) {
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if (ep->ee_priority != EHE_DEAD_PRIORITY &&
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eg->ee.ee_priority < ep->ee_priority) {
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TAILQ_INSERT_BEFORE(ep, &eg->ee, ee_link);
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break;
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}
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}
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if (ep == NULL)
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TAILQ_INSERT_TAIL(&list->el_entries, &eg->ee, ee_link);
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EHL_UNLOCK(list);
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return(&eg->ee);
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}
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void
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eventhandler_deregister(struct eventhandler_list *list, eventhandler_tag tag)
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{
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struct eventhandler_entry *ep = tag;
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EHL_LOCK_ASSERT(list, MA_OWNED);
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if (ep != NULL) {
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/* remove just this entry */
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if (list->el_runcount == 0) {
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CTR3(KTR_EVH, "%s: removing item %p from \"%s\"", __func__, ep,
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list->el_name);
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TAILQ_REMOVE(&list->el_entries, ep, ee_link);
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free(ep, M_EVENTHANDLER);
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} else {
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CTR3(KTR_EVH, "%s: marking item %p from \"%s\" as dead", __func__,
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ep, list->el_name);
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ep->ee_priority = EHE_DEAD_PRIORITY;
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}
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} else {
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/* remove entire list */
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if (list->el_runcount == 0) {
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CTR2(KTR_EVH, "%s: removing all items from \"%s\"", __func__,
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list->el_name);
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while (!TAILQ_EMPTY(&list->el_entries)) {
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ep = TAILQ_FIRST(&list->el_entries);
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TAILQ_REMOVE(&list->el_entries, ep, ee_link);
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free(ep, M_EVENTHANDLER);
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}
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} else {
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CTR2(KTR_EVH, "%s: marking all items from \"%s\" as dead",
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__func__, list->el_name);
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TAILQ_FOREACH(ep, &list->el_entries, ee_link)
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ep->ee_priority = EHE_DEAD_PRIORITY;
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}
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}
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while (list->el_runcount > 0)
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mtx_sleep(list, &list->el_lock, 0, "evhrm", 0);
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EHL_UNLOCK(list);
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}
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/*
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* Internal version for use when eventhandler list is already locked.
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*/
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static struct eventhandler_list *
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_eventhandler_find_list(const char *name)
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{
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struct eventhandler_list *list;
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mtx_assert(&eventhandler_mutex, MA_OWNED);
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TAILQ_FOREACH(list, &eventhandler_lists, el_link) {
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if (!strcmp(name, list->el_name))
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break;
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}
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return (list);
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}
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/*
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* Lookup a "slow" list by name. Returns with the list locked.
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*/
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struct eventhandler_list *
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eventhandler_find_list(const char *name)
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{
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struct eventhandler_list *list;
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if (!eventhandler_lists_initted)
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return(NULL);
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/* scan looking for the requested list */
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mtx_lock(&eventhandler_mutex);
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list = _eventhandler_find_list(name);
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if (list != NULL)
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EHL_LOCK(list);
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mtx_unlock(&eventhandler_mutex);
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return(list);
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}
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/*
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* Prune "dead" entries from an eventhandler list.
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*/
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void
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eventhandler_prune_list(struct eventhandler_list *list)
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{
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struct eventhandler_entry *ep, *en;
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int pruned = 0;
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CTR2(KTR_EVH, "%s: pruning list \"%s\"", __func__, list->el_name);
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EHL_LOCK_ASSERT(list, MA_OWNED);
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TAILQ_FOREACH_SAFE(ep, &list->el_entries, ee_link, en) {
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if (ep->ee_priority == EHE_DEAD_PRIORITY) {
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TAILQ_REMOVE(&list->el_entries, ep, ee_link);
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free(ep, M_EVENTHANDLER);
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pruned++;
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}
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}
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if (pruned > 0)
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wakeup(list);
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}
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