The patch titled
pm-introduce-new-interfaces-schedule_work_on-and-queue_work_on-cleanup
has been removed from the -mm tree. Its filename was
pm-introduce-new-interfaces-schedule_work_on-and-queue_work_on-cleanup.patch
This patch was dropped because it was folded into pm-introduce-new-interfaces-schedule_work_on-and-queue_work_on.patch
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: pm-introduce-new-interfaces-schedule_work_on-and-queue_work_on-cleanup
From: Oleg Nesterov <oleg@xxxxxxxxxx>
The comment above __queue_work() is wrong, we don't need to disable
preemtion.
What it actually means is: the caller of __queue_work() must ensure
we can't race with CPU_DEAD, but preempt_disable() can't help for
queue_work_on(). CPU can die even before preempt_disable().
Remove preempt_disable() and update the comment.
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Zhang Rui <rui.zhang@xxxxxxxxx>
Cc: Rus <harbour@xxxxxxxxxxx>
Cc: Rafael J. Wysocki <rjw@xxxxxxx>
Cc: Pavel Machek <pavel@xxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/workqueue.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff -puN kernel/workqueue.c~pm-introduce-new-interfaces-schedule_work_on-and-queue_work_on-cleanup kernel/workqueue.c
--- a/kernel/workqueue.c~pm-introduce-new-interfaces-schedule_work_on-and-queue_work_on-cleanup
+++ a/kernel/workqueue.c
@@ -140,7 +140,6 @@ static void insert_work(struct cpu_workq
wake_up(&cwq->more_work);
}
-/* Preempt must be disabled. */
static void __queue_work(struct cpu_workqueue_struct *cwq,
struct work_struct *work)
{
@@ -183,7 +182,8 @@ EXPORT_SYMBOL_GPL(queue_work);
*
* Returns 0 if @work was already on a queue, non-zero otherwise.
*
- * We queue the work to a specific CPU
+ * We queue the work to a specific CPU, the caller must ensure it
+ * can't go away.
*/
int
queue_work_on(int cpu, struct workqueue_struct *wq, struct work_struct *work)
@@ -192,9 +192,7 @@ queue_work_on(int cpu, struct workqueue_
if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) {
BUG_ON(!list_empty(&work->entry));
- preempt_disable();
__queue_work(wq_per_cpu(wq, cpu), work);
- preempt_enable();
ret = 1;
}
return ret;
_
Patches currently in -mm which might be from oleg@xxxxxxxxxx are
origin.patch
pm-introduce-new-interfaces-schedule_work_on-and-queue_work_on.patch
pm-introduce-new-interfaces-schedule_work_on-and-queue_work_on-cleanup.patch
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