- Remove the global ithread_list_lock spin lock in favor of per-ithread
sleep locks. - Delay returning from ithread_remove_handler() until we are certain that the interrupt handler being removed has in fact been removed from the ithread. - XXX: There is still a problem in that nothing protects the kernel from adding a new handler while the ithread is running, though with our current architectures this is not a problem. Requested by: gibbs (2)
This commit is contained in:
John Baldwin
parent
7a08bae6ec
commit
4d29cb2db9
@ -62,13 +62,10 @@ void *softclock_ih;
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struct ithd *clk_ithd;
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struct ithd *tty_ithd;
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static struct mtx ithread_list_lock;
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static MALLOC_DEFINE(M_ITHREAD, "ithread", "Interrupt Threads");
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static void ithread_update(struct ithd *);
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static void ithread_loop(void *);
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static void ithread_init(void *);
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static void start_softintr(void *);
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static void swi_net(void *);
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@ -120,6 +117,7 @@ ithread_update(struct ithd *ithd)
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struct proc *p;
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int entropy;
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mtx_assert(&ithd->it_lock, MA_OWNED);
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p = ithd->it_proc;
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if (p == NULL)
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return;
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@ -178,6 +176,8 @@ ithread_create(struct ithd **ithread, int vector, int flags,
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ithd->it_enable = enable;
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ithd->it_flags = flags;
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TAILQ_INIT(&ithd->it_handlers);
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mtx_init(&ithd->it_lock, "ithread", MTX_DEF);
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mtx_lock(&ithd->it_lock);
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va_start(ap, fmt);
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vsnprintf(ithd->it_name, sizeof(ithd->it_name), fmt, ap);
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@ -186,6 +186,7 @@ ithread_create(struct ithd **ithread, int vector, int flags,
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error = kthread_create(ithread_loop, ithd, &p, RFSTOPPED | RFHIGHPID,
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"%s", ithd->it_name);
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if (error) {
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mtx_destroy(&ithd->it_lock);
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free(ithd, M_ITHREAD);
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return (error);
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}
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@ -196,6 +197,7 @@ ithread_create(struct ithd **ithread, int vector, int flags,
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p->p_ithd = ithd;
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if (ithread != NULL)
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*ithread = ithd;
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mtx_unlock(&ithd->it_lock);
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CTR1(KTR_INTR, __func__ ": created %s", ithd->it_name);
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return (0);
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@ -205,16 +207,22 @@ int
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ithread_destroy(struct ithd *ithread)
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{
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if (ithread == NULL || !TAILQ_EMPTY(&ithread->it_handlers))
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if (ithread == NULL)
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return (EINVAL);
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mtx_lock_spin(&sched_lock);
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mtx_lock(&ithread->it_lock);
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if (!TAILQ_EMPTY(&ithread->it_handlers)) {
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mtx_unlock(&ithread->it_lock);
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return (EINVAL);
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}
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ithread->it_flags |= IT_DEAD;
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mtx_lock_spin(&sched_lock);
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if (ithread->it_proc->p_stat == SWAIT) {
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ithread->it_proc->p_stat = SRUN;
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setrunqueue(ithread->it_proc);
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}
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mtx_unlock_spin(&sched_lock);
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mtx_unlock(&ithread->it_lock);
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CTR1(KTR_INTR, __func__ ": killing %s", ithread->it_name);
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return (0);
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}
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@ -246,7 +254,7 @@ ithread_add_handler(struct ithd* ithread, const char *name,
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if (flags & INTR_ENTROPY)
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ih->ih_flags |= IH_ENTROPY;
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mtx_lock_spin(&ithread_list_lock);
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mtx_lock(&ithread->it_lock);
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if ((flags & INTR_EXCL) !=0 && !TAILQ_EMPTY(&ithread->it_handlers))
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goto fail;
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if (!TAILQ_EMPTY(&ithread->it_handlers) &&
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@ -261,7 +269,7 @@ ithread_add_handler(struct ithd* ithread, const char *name,
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else
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TAILQ_INSERT_BEFORE(temp_ih, ih, ih_next);
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ithread_update(ithread);
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mtx_unlock_spin(&ithread_list_lock);
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mtx_unlock(&ithread->it_lock);
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if (cookiep != NULL)
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*cookiep = ih;
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@ -270,7 +278,7 @@ ithread_add_handler(struct ithd* ithread, const char *name,
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return (0);
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fail:
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mtx_unlock_spin(&ithread_list_lock);
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mtx_unlock(&ithread->it_lock);
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free(ih, M_ITHREAD);
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return (EINVAL);
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}
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@ -292,12 +300,12 @@ ithread_remove_handler(void *cookie)
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handler->ih_name));
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CTR2(KTR_INTR, __func__ ": removing %s from %s", handler->ih_name,
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ithread->it_name);
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mtx_lock_spin(&ithread_list_lock);
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mtx_lock(&ithread->it_lock);
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#ifdef INVARIANTS
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TAILQ_FOREACH(ih, &ithread->it_handlers, ih_next)
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if (ih == handler)
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goto ok;
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mtx_unlock_spin(&ithread_list_lock);
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mtx_unlock(&ithread->it_lock);
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panic("interrupt handler \"%s\" not found in interrupt thread \"%s\"",
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ih->ih_name, ithread->it_name);
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ok:
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@ -316,15 +324,14 @@ ithread_remove_handler(void *cookie)
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* it on the list.
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*/
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ithread->it_need = 1;
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} else {
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} else
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TAILQ_REMOVE(&ithread->it_handlers, handler, ih_next);
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ithread_update(ithread);
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}
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mtx_unlock_spin(&sched_lock);
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mtx_unlock_spin(&ithread_list_lock);
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if ((handler->ih_flags & IH_DEAD) == 0)
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free(handler, M_ITHREAD);
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if ((handler->ih_flags & IH_DEAD) != 0)
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msleep(handler, &ithread->it_lock, PUSER, "itrmh", 0);
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ithread_update(ithread);
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mtx_unlock(&ithread->it_lock);
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free(handler, M_ITHREAD);
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return (0);
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}
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@ -473,6 +480,7 @@ ithread_loop(void *arg)
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CTR2(KTR_INTR, __func__ ": pid %d: (%s) exiting",
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p->p_pid, p->p_comm);
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p->p_ithd = NULL;
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mtx_destroy(&ithd->it_lock);
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mtx_lock(&Giant);
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free(ithd, M_ITHREAD);
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kthread_exit(0);
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@ -499,20 +507,16 @@ ithread_loop(void *arg)
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(void *)ih->ih_handler, ih->ih_argument,
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ih->ih_flags);
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if ((ih->ih_flags & IH_MPSAFE) == 0)
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mtx_lock(&Giant);
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if ((ih->ih_flags & IH_DEAD) != 0) {
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mtx_lock_spin(&ithread_list_lock);
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mtx_lock(&ithd->it_lock);
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TAILQ_REMOVE(&ithd->it_handlers, ih,
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ih_next);
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ithread_update(ithd);
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mtx_unlock_spin(&ithread_list_lock);
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if (!mtx_owned(&Giant))
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mtx_lock(&Giant);
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free(ih, M_ITHREAD);
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mtx_unlock(&Giant);
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wakeup(ih);
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mtx_unlock(&ithd->it_lock);
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goto restart;
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}
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if ((ih->ih_flags & IH_MPSAFE) == 0)
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mtx_lock(&Giant);
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ih->ih_handler(ih->ih_argument);
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if ((ih->ih_flags & IH_MPSAFE) == 0)
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mtx_unlock(&Giant);
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@ -541,17 +545,6 @@ ithread_loop(void *arg)
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}
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}
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/*
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* Initialize mutex used to protect ithread handler lists.
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*/
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static void
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ithread_init(void *dummy)
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{
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mtx_init(&ithread_list_lock, "ithread list lock", MTX_SPIN);
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}
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SYSINIT(ithread_init, SI_SUB_INTR, SI_ORDER_FIRST, ithread_init, NULL);
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/*
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* Start standard software interrupt threads
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*/
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@ -29,6 +29,9 @@
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#ifndef _SYS_INTERRUPT_H_
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#define _SYS_INTERRUPT_H_
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#include <sys/_lock.h>
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#include <sys/_mutex.h>
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/*
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* Describe a hardware interrupt handler.
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*
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@ -59,6 +62,7 @@ struct intrhand {
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* not be an actual kernel thread attached to a given source.
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*/
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struct ithd {
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struct mtx it_lock;
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struct proc *it_proc; /* Interrupt process. */
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LIST_ENTRY(ithd) it_list; /* All interrupt threads. */
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TAILQ_HEAD(, intrhand) it_handlers; /* Interrupt handlers. */
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