Module Name: src
Committed By: riastradh
Date: Sun Dec 19 12:42:15 UTC 2021
Modified Files:
src/sys/external/bsd/drm2/linux: linux_kthread.c
Log Message:
drm: Trigger `spurious' wakeup for kthread_stop too.
To generate a diff of this commit:
cvs rdiff -u -r1.4 -r1.5 src/sys/external/bsd/drm2/linux/linux_kthread.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/external/bsd/drm2/linux/linux_kthread.c
diff -u src/sys/external/bsd/drm2/linux/linux_kthread.c:1.4 src/sys/external/bsd/drm2/linux/linux_kthread.c:1.5
--- src/sys/external/bsd/drm2/linux/linux_kthread.c:1.4 Sun Dec 19 12:38:56 2021
+++ src/sys/external/bsd/drm2/linux/linux_kthread.c Sun Dec 19 12:42:14 2021
@@ -1,4 +1,4 @@
-/* $NetBSD: linux_kthread.c,v 1.4 2021/12/19 12:38:56 riastradh Exp $ */
+/* $NetBSD: linux_kthread.c,v 1.5 2021/12/19 12:42:14 riastradh Exp $ */
/*-
* Copyright (c) 2021 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: linux_kthread.c,v 1.4 2021/12/19 12:38:56 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: linux_kthread.c,v 1.5 2021/12/19 12:42:14 riastradh Exp $");
#include <sys/types.h>
@@ -150,18 +150,56 @@ kthread_run(int (*func)(void *), void *c
return T;
}
+/*
+ * lwp_kick(l)
+ *
+ * Cause l to wake up if it is asleep, no matter what condvar or
+ * other wchan it's asleep on. This logic is like sleepq_timeout,
+ * but without setting LW_STIMO. This is not a general-purpose
+ * mechanism -- don't go around using this instead of condvars.
+ */
+static void
+lwp_kick(struct lwp *l)
+{
+
+ lwp_lock(l);
+ if (l->l_wchan == NULL) {
+ /* Not sleeping, so no need to wake up. */
+ lwp_unlock(l);
+ } else {
+ /*
+ * Sleeping, so wake it up. lwp_unsleep has the side
+ * effect of unlocking l when we pass unlock=true.
+ */
+ lwp_unsleep(l, /*unlock*/true);
+ }
+}
+
int
kthread_stop(struct task_struct *T)
{
+ struct lwp *l;
int ret;
+ /*
+ * Notify the thread that it's stopping, and wake it if it's
+ * parked.
+ */
mutex_enter(&T->kt_lock);
T->kt_shouldpark = false;
T->kt_shouldstop = true;
cv_broadcast(&T->kt_cv);
mutex_exit(&T->kt_lock);
- ret = kthread_join(T->kt_lwp);
+ /*
+ * Kick the lwp in case it's waiting on anything else, and then
+ * wait for it to complete. It is the thread's obligation to
+ * check kthread_shouldstop before sleeping again.
+ */
+ l = T->kt_lwp;
+ KASSERT(l != curlwp);
+ lwp_kick(l);
+ ret = kthread_join(l);
kthread_free(T);
@@ -201,23 +239,9 @@ kthread_park(struct task_struct *T)
/*
* If the thread is asleep for any reason, give it a spurious
* wakeup. The thread is responsible for checking
- * kthread_shouldpark before sleeping. This logic is like
- * sleepq_timeout, but without setting LW_STIMO.
+ * kthread_shouldpark before sleeping.
*/
- lwp_lock(l);
- if (l->l_wchan == NULL) {
- /*
- * Not sleeping, so no need to wake up -- the thread
- * will eventually check kthread_shouldpark.
- */
- lwp_unlock(l);
- } else {
- /*
- * Sleeping, so wake it up. lwp_unsleep has the side
- * effect of unlocking l when we pass unlock=true.
- */
- lwp_unsleep(l, /*unlock*/true);
- }
+ lwp_kick(l);
/* Wait until the thread has issued kthread_parkme. */
while (!T->kt_parked)
