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-rw-r--r--kernel/softirq.c20
1 files changed, 12 insertions, 8 deletions
diff --git a/kernel/softirq.c b/kernel/softirq.c
index 3c44956ee7e..36e06174004 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -589,16 +589,20 @@ static void takeover_tasklets(unsigned int cpu)
local_irq_disable();
/* Find end, append list for that CPU. */
- *__get_cpu_var(tasklet_vec).tail = per_cpu(tasklet_vec, cpu).head;
- __get_cpu_var(tasklet_vec).tail = per_cpu(tasklet_vec, cpu).tail;
- per_cpu(tasklet_vec, cpu).head = NULL;
- per_cpu(tasklet_vec, cpu).tail = &per_cpu(tasklet_vec, cpu).head;
+ if (&per_cpu(tasklet_vec, cpu).head != per_cpu(tasklet_vec, cpu).tail) {
+ *(__get_cpu_var(tasklet_vec).tail) = per_cpu(tasklet_vec, cpu).head;
+ __get_cpu_var(tasklet_vec).tail = per_cpu(tasklet_vec, cpu).tail;
+ per_cpu(tasklet_vec, cpu).head = NULL;
+ per_cpu(tasklet_vec, cpu).tail = &per_cpu(tasklet_vec, cpu).head;
+ }
raise_softirq_irqoff(TASKLET_SOFTIRQ);
- *__get_cpu_var(tasklet_hi_vec).tail = per_cpu(tasklet_hi_vec, cpu).head;
- __get_cpu_var(tasklet_hi_vec).tail = per_cpu(tasklet_hi_vec, cpu).tail;
- per_cpu(tasklet_hi_vec, cpu).head = NULL;
- per_cpu(tasklet_hi_vec, cpu).tail = &per_cpu(tasklet_hi_vec, cpu).head;
+ if (&per_cpu(tasklet_hi_vec, cpu).head != per_cpu(tasklet_hi_vec, cpu).tail) {
+ *__get_cpu_var(tasklet_hi_vec).tail = per_cpu(tasklet_hi_vec, cpu).head;
+ __get_cpu_var(tasklet_hi_vec).tail = per_cpu(tasklet_hi_vec, cpu).tail;
+ per_cpu(tasklet_hi_vec, cpu).head = NULL;
+ per_cpu(tasklet_hi_vec, cpu).tail = &per_cpu(tasklet_hi_vec, cpu).head;
+ }
raise_softirq_irqoff(HI_SOFTIRQ);
local_irq_enable();