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-rw-r--r--kernel/workqueue.c14
1 files changed, 9 insertions, 5 deletions
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 0f50f4078e36..eeae77079483 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -533,9 +533,9 @@ static int work_next_color(int color)
}
/*
- * A work's data points to the cwq with WORK_STRUCT_CWQ set while the
- * work is on queue. Once execution starts, WORK_STRUCT_CWQ is
- * cleared and the work data contains the cpu number it was last on.
+ * While queued, %WORK_STRUCT_CWQ is set and non flag bits of a work's data
+ * contain the pointer to the queued cwq. Once execution starts, the flag
+ * is cleared and the high bits contain OFFQ flags and CPU number.
*
* set_work_cwq(), set_work_cpu_and_clear_pending() and clear_work_data()
* can be used to set the cwq, cpu or clear work->data. These functions
@@ -565,7 +565,7 @@ static void set_work_cwq(struct work_struct *work,
static void set_work_cpu_and_clear_pending(struct work_struct *work,
unsigned int cpu)
{
- set_work_data(work, cpu << WORK_STRUCT_FLAG_BITS, 0);
+ set_work_data(work, (unsigned long)cpu << WORK_OFFQ_CPU_SHIFT, 0);
}
static void clear_work_data(struct work_struct *work)
@@ -592,7 +592,7 @@ static struct global_cwq *get_work_gcwq(struct work_struct *work)
return ((struct cpu_workqueue_struct *)
(data & WORK_STRUCT_WQ_DATA_MASK))->pool->gcwq;
- cpu = data >> WORK_STRUCT_FLAG_BITS;
+ cpu = data >> WORK_OFFQ_CPU_SHIFT;
if (cpu == WORK_CPU_NONE)
return NULL;
@@ -3724,6 +3724,10 @@ static int __init init_workqueues(void)
unsigned int cpu;
int i;
+ /* make sure we have enough bits for OFFQ CPU number */
+ BUILD_BUG_ON((1LU << (BITS_PER_LONG - WORK_OFFQ_CPU_SHIFT)) <
+ WORK_CPU_LAST);
+
cpu_notifier(workqueue_cpu_up_callback, CPU_PRI_WORKQUEUE_UP);
cpu_notifier(workqueue_cpu_down_callback, CPU_PRI_WORKQUEUE_DOWN);
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