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Diffstat (limited to 'kernel/softirq.c')
-rw-r--r--kernel/softirq.c63
1 files changed, 41 insertions, 22 deletions
diff --git a/kernel/softirq.c b/kernel/softirq.c
index 31e9f2a4792..3c44956ee7e 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -356,7 +356,8 @@ void open_softirq(int nr, void (*action)(struct softirq_action*), void *data)
/* Tasklets */
struct tasklet_head
{
- struct tasklet_struct *list;
+ struct tasklet_struct *head;
+ struct tasklet_struct **tail;
};
/* Some compilers disobey section attribute on statics when not
@@ -369,8 +370,9 @@ void __tasklet_schedule(struct tasklet_struct *t)
unsigned long flags;
local_irq_save(flags);
- t->next = __get_cpu_var(tasklet_vec).list;
- __get_cpu_var(tasklet_vec).list = t;
+ t->next = NULL;
+ *__get_cpu_var(tasklet_vec).tail = t;
+ __get_cpu_var(tasklet_vec).tail = &(t->next);
raise_softirq_irqoff(TASKLET_SOFTIRQ);
local_irq_restore(flags);
}
@@ -382,8 +384,9 @@ void __tasklet_hi_schedule(struct tasklet_struct *t)
unsigned long flags;
local_irq_save(flags);
- t->next = __get_cpu_var(tasklet_hi_vec).list;
- __get_cpu_var(tasklet_hi_vec).list = t;
+ t->next = NULL;
+ *__get_cpu_var(tasklet_hi_vec).tail = t;
+ __get_cpu_var(tasklet_hi_vec).tail = &(t->next);
raise_softirq_irqoff(HI_SOFTIRQ);
local_irq_restore(flags);
}
@@ -395,8 +398,9 @@ static void tasklet_action(struct softirq_action *a)
struct tasklet_struct *list;
local_irq_disable();
- list = __get_cpu_var(tasklet_vec).list;
- __get_cpu_var(tasklet_vec).list = NULL;
+ list = __get_cpu_var(tasklet_vec).head;
+ __get_cpu_var(tasklet_vec).head = NULL;
+ __get_cpu_var(tasklet_vec).tail = &__get_cpu_var(tasklet_vec).head;
local_irq_enable();
while (list) {
@@ -416,8 +420,9 @@ static void tasklet_action(struct softirq_action *a)
}
local_irq_disable();
- t->next = __get_cpu_var(tasklet_vec).list;
- __get_cpu_var(tasklet_vec).list = t;
+ t->next = NULL;
+ *__get_cpu_var(tasklet_vec).tail = t;
+ __get_cpu_var(tasklet_vec).tail = &(t->next);
__raise_softirq_irqoff(TASKLET_SOFTIRQ);
local_irq_enable();
}
@@ -428,8 +433,9 @@ static void tasklet_hi_action(struct softirq_action *a)
struct tasklet_struct *list;
local_irq_disable();
- list = __get_cpu_var(tasklet_hi_vec).list;
- __get_cpu_var(tasklet_hi_vec).list = NULL;
+ list = __get_cpu_var(tasklet_hi_vec).head;
+ __get_cpu_var(tasklet_hi_vec).head = NULL;
+ __get_cpu_var(tasklet_hi_vec).tail = &__get_cpu_var(tasklet_hi_vec).head;
local_irq_enable();
while (list) {
@@ -449,8 +455,9 @@ static void tasklet_hi_action(struct softirq_action *a)
}
local_irq_disable();
- t->next = __get_cpu_var(tasklet_hi_vec).list;
- __get_cpu_var(tasklet_hi_vec).list = t;
+ t->next = NULL;
+ *__get_cpu_var(tasklet_hi_vec).tail = t;
+ __get_cpu_var(tasklet_hi_vec).tail = &(t->next);
__raise_softirq_irqoff(HI_SOFTIRQ);
local_irq_enable();
}
@@ -487,6 +494,15 @@ EXPORT_SYMBOL(tasklet_kill);
void __init softirq_init(void)
{
+ int cpu;
+
+ for_each_possible_cpu(cpu) {
+ per_cpu(tasklet_vec, cpu).tail =
+ &per_cpu(tasklet_vec, cpu).head;
+ per_cpu(tasklet_hi_vec, cpu).tail =
+ &per_cpu(tasklet_hi_vec, cpu).head;
+ }
+
open_softirq(TASKLET_SOFTIRQ, tasklet_action, NULL);
open_softirq(HI_SOFTIRQ, tasklet_hi_action, NULL);
}
@@ -555,9 +571,12 @@ void tasklet_kill_immediate(struct tasklet_struct *t, unsigned int cpu)
return;
/* CPU is dead, so no lock needed. */
- for (i = &per_cpu(tasklet_vec, cpu).list; *i; i = &(*i)->next) {
+ for (i = &per_cpu(tasklet_vec, cpu).head; *i; i = &(*i)->next) {
if (*i == t) {
*i = t->next;
+ /* If this was the tail element, move the tail ptr */
+ if (*i == NULL)
+ per_cpu(tasklet_vec, cpu).tail = i;
return;
}
}
@@ -566,20 +585,20 @@ void tasklet_kill_immediate(struct tasklet_struct *t, unsigned int cpu)
static void takeover_tasklets(unsigned int cpu)
{
- struct tasklet_struct **i;
-
/* CPU is dead, so no lock needed. */
local_irq_disable();
/* Find end, append list for that CPU. */
- for (i = &__get_cpu_var(tasklet_vec).list; *i; i = &(*i)->next);
- *i = per_cpu(tasklet_vec, cpu).list;
- per_cpu(tasklet_vec, cpu).list = NULL;
+ *__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);
- for (i = &__get_cpu_var(tasklet_hi_vec).list; *i; i = &(*i)->next);
- *i = per_cpu(tasklet_hi_vec, cpu).list;
- per_cpu(tasklet_hi_vec, cpu).list = NULL;
+ *__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();