- Convert the per-eventhandler list mutex to a lockmgr lock so that it can
be safely held across an eventhandler function call. - Fix an instance of the head of an eventhandler list being read without the lock being held. - Break down and use a SYSINIT at the new SI_SUB_EVENTHANDLER to initialize the eventhandler global mutex and the eventhandler list of lists rather than using a non-MP safe initialization during the first call to eventhandler_register(). - Add in a KASSERT() to eventhandler_register() to ensure that we don't try to register an eventhandler before things have been initialized.
This commit is contained in:
John Baldwin
parent
18f619abce
commit
06592dd188
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=69893
@ -29,6 +29,7 @@
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#include <sys/param.h>
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#include <sys/kernel.h>
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#include <sys/malloc.h>
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#include <sys/mutex.h>
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#include <sys/systm.h>
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#include <sys/eventhandler.h>
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@ -45,6 +46,19 @@ struct eventhandler_entry_generic
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void (* func)(void);
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};
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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", MTX_DEF);
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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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@ -56,12 +70,7 @@ eventhandler_register(struct eventhandler_list *list, char *name,
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struct eventhandler_entry_generic *eg;
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struct eventhandler_entry *ep;
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/* avoid the need for a SYSINIT just to init the list */
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if (!eventhandler_lists_initted) {
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TAILQ_INIT(&eventhandler_lists);
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mtx_init(&eventhandler_mutex, "eventhandler", MTX_DEF);
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eventhandler_lists_initted = 1;
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}
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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_enter(&eventhandler_mutex, MTX_DEF);
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@ -86,7 +95,7 @@ eventhandler_register(struct eventhandler_list *list, char *name,
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}
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if (!(list->el_flags & EHE_INITTED)) {
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TAILQ_INIT(&list->el_entries);
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mtx_init(&list->el_mutex, name, MTX_DEF);
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lockinit(&list->el_lock, PZERO, name, 0, 0);
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list->el_flags = EHE_INITTED;
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}
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@ -101,7 +110,7 @@ eventhandler_register(struct eventhandler_list *list, char *name,
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eg->ee.ee_priority = priority;
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/* sort it into the list */
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mtx_enter(&list->el_mutex, MTX_DEF);
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lockmgr(&list->el_lock, LK_EXCLUSIVE, NULL, CURPROC);
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for (ep = TAILQ_FIRST(&list->el_entries);
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ep != NULL;
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ep = TAILQ_NEXT(ep, ee_link)) {
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@ -112,7 +121,7 @@ eventhandler_register(struct eventhandler_list *list, char *name,
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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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mtx_exit(&list->el_mutex, MTX_DEF);
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lockmgr(&list->el_lock, LK_RELEASE, NULL, CURPROC);
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mtx_exit(&eventhandler_mutex, MTX_DEF);
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return(&eg->ee);
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}
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@ -123,7 +132,7 @@ eventhandler_deregister(struct eventhandler_list *list, eventhandler_tag tag)
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struct eventhandler_entry *ep = tag;
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/* XXX insert diagnostic check here? */
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mtx_enter(&list->el_mutex, MTX_DEF);
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lockmgr(&list->el_lock, LK_EXCLUSIVE, NULL, CURPROC);
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if (ep != NULL) {
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/* remove just this entry */
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TAILQ_REMOVE(&list->el_entries, ep, ee_link);
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@ -136,7 +145,7 @@ eventhandler_deregister(struct eventhandler_list *list, eventhandler_tag tag)
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free(ep, M_EVENTHANDLER);
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}
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}
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mtx_exit(&list->el_mutex, MTX_DEF);
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lockmgr(&list->el_lock, LK_RELEASE, NULL, CURPROC);
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}
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struct eventhandler_list *
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@ -30,7 +30,7 @@
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#define SYS_EVENTHANDLER_H
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#include <sys/queue.h>
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#include <sys/mutex.h>
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#include <sys/lock.h>
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struct eventhandler_entry
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{
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@ -44,7 +44,7 @@ struct eventhandler_list
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char *el_name;
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int el_flags;
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#define EHE_INITTED (1<<0)
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struct mtx el_mutex;
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struct lock el_lock;
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TAILQ_ENTRY(eventhandler_list) el_link;
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TAILQ_HEAD(,eventhandler_entry) el_entries;
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};
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@ -77,18 +77,18 @@ struct __hack
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#define EVENTHANDLER_FAST_INVOKE(name, args...) \
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do { \
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struct eventhandler_list *_el = &Xeventhandler_list_ ## name ; \
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struct eventhandler_entry *_ep = TAILQ_FIRST(&(_el->el_entries)); \
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struct eventhandler_entry *_en; \
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struct eventhandler_entry *_ep, *_en; \
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\
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if (_el->el_flags & EHE_INITTED) { \
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lockmgr(&_el->el_lock, LK_EXCLUSIVE, NULL, CURPROC); \
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_ep = TAILQ_FIRST(&(_el->el_entries)); \
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while (_ep != NULL) { \
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mtx_enter(&_el->el_mutex, MTX_DEF); \
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_en = TAILQ_NEXT(_ep, ee_link); \
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mtx_exit(&_el->el_mutex, MTX_DEF); \
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((struct eventhandler_entry_ ## name *)_ep)->eh_func(_ep->ee_arg , \
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## args); \
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_ep = _en; \
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} \
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lockmgr(&_el->el_lock, LK_RELEASE, NULL, CURPROC); \
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} \
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} while (0)
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@ -120,17 +120,15 @@ do { \
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\
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if (((_el = eventhandler_find_list(#name)) != NULL) && \
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(_el->el_flags & EHE_INITTED)) { \
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mtx_enter(&_el->el_mutex, MTX_DEF); \
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lockmgr(&_el->el_lock, LK_EXCLUSIVE, NULL, CURPROC); \
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_ep = TAILQ_FIRST(&(_el->el_entries)); \
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mtx_exit(&_el->el_mutex, MTX_DEF); \
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while (_ep != NULL) { \
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mtx_enter(&_el->el_mutex, MTX_DEF); \
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_en = TAILQ_NEXT(_ep, ee_link); \
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mtx_exit(&_el->el_mutex, MTX_DEF); \
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((struct eventhandler_entry_ ## name *)_ep)->eh_func(_ep->ee_arg , \
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## args); \
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_ep = _en; \
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} \
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lockmgr(&_el->el_lock, LK_RELEASE, NULL, CURPROC); \
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} \
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} while (0)
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@ -114,6 +114,7 @@ enum sysinit_sub_id {
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SI_SUB_KMEM = 0x1800000, /* kernel memory*/
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SI_SUB_KVM_RSRC = 0x1A00000, /* kvm operational limits*/
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SI_SUB_LOCK = 0x1B00000, /* lockmgr locks */
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SI_SUB_EVENTHANDLER = 0x1C00000, /* eventhandler init */
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SI_SUB_CPU = 0x2000000, /* CPU resource(s)*/
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SI_SUB_KLD = 0x2100000, /* KLD and module setup */
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SI_SUB_INTRINSIC = 0x2200000, /* proc 0*/
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