1 files changed, 41 insertions, 22 deletions

diff --git a/kernel/softirq.c b/kernel/softirq.c
index 31e9f2a47928..3c44956ee7e2 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();