Thread (33 messages) 33 messages, 3 authors, 2016-06-29

Re: [PATCH v9 08/12] kthread: Detect when a kthread work is used by more workers

From: Tejun Heo <tj@kernel.org>
Date: 2016-06-20 20:12:55
Also in: linux-mm, lkml

Hello,

On Thu, Jun 16, 2016 at 01:17:27PM +0200, Petr Mladek wrote:
quoted hunk ↗ jump to hunk
diff --git a/kernel/kthread.c b/kernel/kthread.c
index 567ec49b4872..8e9548649c86 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -574,6 +574,9 @@ EXPORT_SYMBOL_GPL(__kthread_init_worker);
  * The works are not allowed to keep any locks, disable preemption or interrupts
  * when they finish. There is defined a safe point for freezing when one work
  * finishes and before a new one is started.
+ *
+ * Also the works must not be handled by more workers at the same time, see also
                                                ^
						than one
quoted hunk ↗ jump to hunk
+ * kthread_queue_work().
  */
 int kthread_worker_fn(void *worker_ptr)
 {
@@ -710,12 +713,21 @@ kthread_create_worker_on_cpu(int cpu, const char namefmt[], ...)
 }
 EXPORT_SYMBOL(kthread_create_worker_on_cpu);
 
+static void kthread_insert_work_sanity_check(struct kthread_worker *worker,
+					     struct kthread_work *work)
+{
+	lockdep_assert_held(&worker->lock);
+	WARN_ON_ONCE(!list_empty(&work->node));
+	/* Do not use a work with more workers, see kthread_queue_work() */
                                  ^
				  ditto, maybe just say ">1 workers"?

Looks good otherwise.

Thanks.

-- 
tejun

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