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authorAndrew Morton <akpm@osdl.org>2007-05-09 02:33:53 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-05-09 12:30:51 -0700
commitedab2516a6c1752e8e5e3d55727cabf12346e5df (patch)
tree235f0e8dd26341a650cc3329e4fc54b3b857aa07 /kernel
parentb89deed32ccc96098bd6bc953c64bba6b847774f (diff)
downloadlwn-edab2516a6c1752e8e5e3d55727cabf12346e5df.tar.gz
lwn-edab2516a6c1752e8e5e3d55727cabf12346e5df.zip
flush_workqueue(): use preempt_disable to hold off cpu hotplug
Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com> Cc: Gautham Shenoy <ego@in.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/workqueue.c16
1 files changed, 10 insertions, 6 deletions
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 918d55267a12..5176d51bcc2a 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -419,18 +419,22 @@ static void flush_cpu_workqueue(struct cpu_workqueue_struct *cwq)
* Probably keventd trying to flush its own queue. So simply run
* it by hand rather than deadlocking.
*/
- mutex_unlock(&workqueue_mutex);
+ preempt_enable();
+ /*
+ * We can still touch *cwq here because we are keventd, and
+ * hot-unplug will be waiting us to exit.
+ */
run_workqueue(cwq);
- mutex_lock(&workqueue_mutex);
+ preempt_disable();
} else {
struct wq_barrier barr;
init_wq_barrier(&barr);
__queue_work(cwq, &barr.work);
- mutex_unlock(&workqueue_mutex);
+ preempt_enable(); /* Can no longer touch *cwq */
wait_for_completion(&barr.done);
- mutex_lock(&workqueue_mutex);
+ preempt_disable();
}
}
@@ -449,7 +453,7 @@ static void flush_cpu_workqueue(struct cpu_workqueue_struct *cwq)
*/
void fastcall flush_workqueue(struct workqueue_struct *wq)
{
- mutex_lock(&workqueue_mutex);
+ preempt_disable(); /* CPU hotplug */
if (is_single_threaded(wq)) {
/* Always use first cpu's area. */
flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, singlethread_cpu));
@@ -459,7 +463,7 @@ void fastcall flush_workqueue(struct workqueue_struct *wq)
for_each_online_cpu(cpu)
flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, cpu));
}
- mutex_unlock(&workqueue_mutex);
+ preempt_enable();
}
EXPORT_SYMBOL_GPL(flush_workqueue);