kthread: add kthread_stop_put

Add a kthread_stop_put() helper that stops a thread and puts its task
struct.  Use it to replace the various instances of kthread_stop()
followed by put_task_struct().

Remove the kthread_stop_put() macro in usbip that is similar but doesn't
return the result of kthread_stop().

[agruenba@redhat.com: fix kerneldoc comment]
  Link: https://lkml.kernel.org/r/20230911111730.2565537-1-agruenba@redhat.com
[akpm@linux-foundation.org: document kthread_stop_put()'s argument]
Link: https://lkml.kernel.org/r/20230907234048.2499820-1-agruenba@redhat.com
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 18 insertions, 0 deletions

diff --git a/kernel/kthread.c b/kernel/kthread.c
index 1eea53050bab..290cbc845225 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -715,6 +715,24 @@ int kthread_stop(struct task_struct *k)
 }
 EXPORT_SYMBOL(kthread_stop);
 
+/**
+ * kthread_stop_put - stop a thread and put its task struct
+ * @k: thread created by kthread_create().
+ *
+ * Stops a thread created by kthread_create() and put its task_struct.
+ * Only use when holding an extra task struct reference obtained by
+ * calling get_task_struct().
+ */
+int kthread_stop_put(struct task_struct *k)
+{
+	int ret;
+
+	ret = kthread_stop(k);
+	put_task_struct(k);
+	return ret;
+}
+EXPORT_SYMBOL(kthread_stop_put);
+
 int kthreadd(void *unused)
 {
 	struct task_struct *tsk = current;