kernel: Only expose su when daemon is running
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / kernel / softirq.c
index 3d6833f125d307214bae0210bd68cbaaa925755d..dc23e06fc07e8d54fa90694928d3c4d7123d4055 100644 (file)
@@ -6,8 +6,6 @@
  *     Distribute under GPLv2.
  *
  *     Rewritten. Old one was good in 2.2, but in 2.3 it was immoral. --ANK (990903)
- *
- *     Remote softirq infrastructure is by Jens Axboe.
  */
 
 #include <linux/export.h>
@@ -26,6 +24,7 @@
 #include <linux/smpboot.h>
 #include <linux/tick.h>
 
+#include <linux/mt_sched_mon.h>
 #define CREATE_TRACE_POINTS
 #include <trace/events/irq.h>
 
@@ -250,7 +249,9 @@ restart:
                        kstat_incr_softirqs_this_cpu(vec_nr);
 
                        trace_softirq_entry(vec_nr);
-                       h->action(h);
+            mt_trace_SoftIRQ_start(vec_nr);
+            h->action(h);
+            mt_trace_SoftIRQ_end(vec_nr);
                        trace_softirq_exit(vec_nr);
                        if (unlikely(prev_count != preempt_count())) {
                                printk(KERN_ERR "huh, entered softirq %u %s %p"
@@ -330,10 +331,19 @@ void irq_enter(void)
 
 static inline void invoke_softirq(void)
 {
-       if (!force_irqthreads)
-               __do_softirq();
-       else
+       if (!force_irqthreads) {
+               /*
+                * We can safely execute softirq on the current stack if
+                * it is the irq stack, because it should be near empty
+                * at this stage. But we have no way to know if the arch
+                * calls irq_exit() on the irq stack. So call softirq
+                * in its own stack to prevent from any overrun on top
+                * of a potentially deep task stack.
+                */
+               do_softirq();
+       } else {
                wakeup_softirqd();
+       }
 }
 
 static inline void tick_irq_exit(void)
@@ -480,7 +490,9 @@ static void tasklet_action(struct softirq_action *a)
                        if (!atomic_read(&t->count)) {
                                if (!test_and_clear_bit(TASKLET_STATE_SCHED, &t->state))
                                        BUG();
+                mt_trace_tasklet_start(t->func);
                                t->func(t->data);
+                mt_trace_tasklet_end(t->func);
                                tasklet_unlock(t);
                                continue;
                        }
@@ -611,146 +623,17 @@ void tasklet_hrtimer_init(struct tasklet_hrtimer *ttimer,
 }
 EXPORT_SYMBOL_GPL(tasklet_hrtimer_init);
 
-/*
- * Remote softirq bits
- */
-
-DEFINE_PER_CPU(struct list_head [NR_SOFTIRQS], softirq_work_list);
-EXPORT_PER_CPU_SYMBOL(softirq_work_list);
-
-static void __local_trigger(struct call_single_data *cp, int softirq)
-{
-       struct list_head *head = &__get_cpu_var(softirq_work_list[softirq]);
-
-       list_add_tail(&cp->list, head);
-
-       /* Trigger the softirq only if the list was previously empty.  */
-       if (head->next == &cp->list)
-               raise_softirq_irqoff(softirq);
-}
-
-#ifdef CONFIG_USE_GENERIC_SMP_HELPERS
-static void remote_softirq_receive(void *data)
-{
-       struct call_single_data *cp = data;
-       unsigned long flags;
-       int softirq;
-
-       softirq = *(int *)cp->info;
-       local_irq_save(flags);
-       __local_trigger(cp, softirq);
-       local_irq_restore(flags);
-}
-
-static int __try_remote_softirq(struct call_single_data *cp, int cpu, int softirq)
-{
-       if (cpu_online(cpu)) {
-               cp->func = remote_softirq_receive;
-               cp->info = &softirq;
-               cp->flags = 0;
-
-               __smp_call_function_single(cpu, cp, 0);
-               return 0;
-       }
-       return 1;
-}
-#else /* CONFIG_USE_GENERIC_SMP_HELPERS */
-static int __try_remote_softirq(struct call_single_data *cp, int cpu, int softirq)
-{
-       return 1;
-}
-#endif
-
-/**
- * __send_remote_softirq - try to schedule softirq work on a remote cpu
- * @cp: private SMP call function data area
- * @cpu: the remote cpu
- * @this_cpu: the currently executing cpu
- * @softirq: the softirq for the work
- *
- * Attempt to schedule softirq work on a remote cpu.  If this cannot be
- * done, the work is instead queued up on the local cpu.
- *
- * Interrupts must be disabled.
- */
-void __send_remote_softirq(struct call_single_data *cp, int cpu, int this_cpu, int softirq)
-{
-       if (cpu == this_cpu || __try_remote_softirq(cp, cpu, softirq))
-               __local_trigger(cp, softirq);
-}
-EXPORT_SYMBOL(__send_remote_softirq);
-
-/**
- * send_remote_softirq - try to schedule softirq work on a remote cpu
- * @cp: private SMP call function data area
- * @cpu: the remote cpu
- * @softirq: the softirq for the work
- *
- * Like __send_remote_softirq except that disabling interrupts and
- * computing the current cpu is done for the caller.
- */
-void send_remote_softirq(struct call_single_data *cp, int cpu, int softirq)
-{
-       unsigned long flags;
-       int this_cpu;
-
-       local_irq_save(flags);
-       this_cpu = smp_processor_id();
-       __send_remote_softirq(cp, cpu, this_cpu, softirq);
-       local_irq_restore(flags);
-}
-EXPORT_SYMBOL(send_remote_softirq);
-
-static int __cpuinit remote_softirq_cpu_notify(struct notifier_block *self,
-                                              unsigned long action, void *hcpu)
-{
-       /*
-        * If a CPU goes away, splice its entries to the current CPU
-        * and trigger a run of the softirq
-        */
-       if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) {
-               int cpu = (unsigned long) hcpu;
-               int i;
-
-               local_irq_disable();
-               for (i = 0; i < NR_SOFTIRQS; i++) {
-                       struct list_head *head = &per_cpu(softirq_work_list[i], cpu);
-                       struct list_head *local_head;
-
-                       if (list_empty(head))
-                               continue;
-
-                       local_head = &__get_cpu_var(softirq_work_list[i]);
-                       list_splice_init(head, local_head);
-                       raise_softirq_irqoff(i);
-               }
-               local_irq_enable();
-       }
-
-       return NOTIFY_OK;
-}
-
-static struct notifier_block __cpuinitdata remote_softirq_cpu_notifier = {
-       .notifier_call  = remote_softirq_cpu_notify,
-};
-
 void __init softirq_init(void)
 {
        int cpu;
 
        for_each_possible_cpu(cpu) {
-               int i;
-
                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;
-               for (i = 0; i < NR_SOFTIRQS; i++)
-                       INIT_LIST_HEAD(&per_cpu(softirq_work_list[i], cpu));
        }
 
-       register_hotcpu_notifier(&remote_softirq_cpu_notifier);
-
        open_softirq(TASKLET_SOFTIRQ, tasklet_action);
        open_softirq(HI_SOFTIRQ, tasklet_hi_action);
 }
@@ -765,9 +648,13 @@ static void run_ksoftirqd(unsigned int cpu)
        local_irq_disable();
        if (local_softirq_pending()) {
                __do_softirq();
-               rcu_note_context_switch(cpu);
                local_irq_enable();
                cond_resched();
+
+               preempt_disable();
+               rcu_note_context_switch(cpu);
+               preempt_enable();
+
                return;
        }
        local_irq_enable();