1 files changed, 33 insertions, 20 deletions

diff --git a/kernel/softirq.c b/kernel/softirq.c
index d7d498d8cc4f..b24988353458 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -29,7 +29,6 @@
 #define CREATE_TRACE_POINTS
 #include <trace/events/irq.h>
 
-#include <asm/irq.h>
 /*
    - No shared variables, all the data are CPU local.
    - If a softirq needs serialization, let it serialize itself
@@ -100,13 +99,13 @@ static void __local_bh_disable(unsigned long ip, unsigned int cnt)
 
         raw_local_irq_save(flags);
         /*
-         * The preempt tracer hooks into add_preempt_count and will break
+         * The preempt tracer hooks into preempt_count_add and will break
          * lockdep because it calls back into lockdep after SOFTIRQ_OFFSET
          * is set and before current->softirq_enabled is cleared.
          * We must manually increment preempt_count here and manually
          * call the trace_preempt_off later.
          */
-        preempt_count() += cnt;
+        __preempt_count_add(cnt);
         /*
          * Were softirqs turned off above:
          */
@@ -120,7 +119,7 @@ static void __local_bh_disable(unsigned long ip, unsigned int cnt)
 #else /* !CONFIG_TRACE_IRQFLAGS */
 static inline void __local_bh_disable(unsigned long ip, unsigned int cnt)
 {
-        add_preempt_count(cnt);
+        preempt_count_add(cnt);
         barrier();
 }
 #endif /* CONFIG_TRACE_IRQFLAGS */
@@ -134,12 +133,11 @@ EXPORT_SYMBOL(local_bh_disable);
 
 static void __local_bh_enable(unsigned int cnt)
 {
-        WARN_ON_ONCE(in_irq());
         WARN_ON_ONCE(!irqs_disabled());
 
         if (softirq_count() == cnt)
                 trace_softirqs_on(_RET_IP_);
-        sub_preempt_count(cnt);
+        preempt_count_sub(cnt);
 }
 
 /*
@@ -149,6 +147,7 @@ static void __local_bh_enable(unsigned int cnt)
  */
 void _local_bh_enable(void)
 {
+        WARN_ON_ONCE(in_irq());
         __local_bh_enable(SOFTIRQ_DISABLE_OFFSET);
 }
 
@@ -169,12 +168,17 @@ static inline void _local_bh_enable_ip(unsigned long ip)
          * Keep preemption disabled until we are done with
          * softirq processing:
          */
-        sub_preempt_count(SOFTIRQ_DISABLE_OFFSET - 1);
+        preempt_count_sub(SOFTIRQ_DISABLE_OFFSET - 1);
 
-        if (unlikely(!in_interrupt() && local_softirq_pending()))
+        if (unlikely(!in_interrupt() && local_softirq_pending())) {
+                /*
+                 * Run softirq if any pending. And do it in its own stack
+                 * as we may be calling this deep in a task call stack already.
+                 */
                 do_softirq();
+        }
 
-        dec_preempt_count();
+        preempt_count_dec();
 #ifdef CONFIG_TRACE_IRQFLAGS
         local_irq_enable();
 #endif
@@ -256,7 +260,7 @@ restart:
                                        " exited with %08x?\n", vec_nr,
                                        softirq_to_name[vec_nr], h->action,
                                        prev_count, preempt_count());
-                                preempt_count() = prev_count;
+                                preempt_count_set(prev_count);
                         }
 
                         rcu_bh_qs(cpu);
@@ -280,10 +284,11 @@ restart:
 
         account_irq_exit_time(current);
         __local_bh_enable(SOFTIRQ_OFFSET);
+        WARN_ON_ONCE(in_interrupt());
         tsk_restore_flags(current, old_flags, PF_MEMALLOC);
 }
 
-#ifndef __ARCH_HAS_DO_SOFTIRQ
+
 
 asmlinkage void do_softirq(void)
 {
@@ -298,13 +303,11 @@ asmlinkage void do_softirq(void)
         pending = local_softirq_pending();
 
         if (pending)
-                __do_softirq();
+                do_softirq_own_stack();
 
         local_irq_restore(flags);
 }
 
-#endif
-
 /*
  * Enter an interrupt context.
  */
@@ -329,15 +332,21 @@ void irq_enter(void)
 static inline void invoke_softirq(void)
 {
         if (!force_irqthreads) {
+#ifdef CONFIG_HAVE_IRQ_EXIT_ON_IRQ_STACK
                 /*
                  * 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.
+                 * at this stage.
                  */
-                do_softirq();
+                __do_softirq();
+#else
+                /*
+                 * Otherwise, irq_exit() is called on the task stack that can
+                 * be potentially deep already. So call softirq in its own stack
+                 * to prevent from any overrun.
+                 */
+                do_softirq_own_stack();
+#endif
         } else {
                 wakeup_softirqd();
         }
@@ -369,7 +378,7 @@ void irq_exit(void)
 
         account_irq_exit_time(current);
         trace_hardirq_exit();
-        sub_preempt_count(HARDIRQ_OFFSET);
+        preempt_count_sub(HARDIRQ_OFFSET);
         if (!in_interrupt() && local_softirq_pending())
                 invoke_softirq();
 
@@ -771,6 +780,10 @@ static void run_ksoftirqd(unsigned int cpu)
 {
         local_irq_disable();
         if (local_softirq_pending()) {
+                /*
+                 * We can safely run softirq on inline stack, as we are not deep
+                 * in the task stack here.
+                 */
                 __do_softirq();
                 rcu_note_context_switch(cpu);
                 local_irq_enable();