Revert "Revert "ANDROID: Revert "softirq: Let ksoftirqd do its job"""

This reverts commit c646ea5a5f, as the
merge conflicts have been resolved.

Bug: 168521633
Change-Id: Ide895e808fd0786b6690334d62d250f73584508e
Signed-off-by: Lingutla Chandrasekhar <clingutla@codeaurora.org>
[satyap@codeaurora.org: Fix trivial merge conflicts]
Signed-off-by: Satya Durga Srinivasu Prabhala <satyap@codeaurora.org>
[elavila: Port to mainline]
Signed-off-by: J. Avila <elavila@google.com>
Signed-off-by: Shaleen Agrawal <shalagra@codeaurora.org>

kernel/softirq.c

@@ -90,19 +90,6 @@ static void wakeup_softirqd(void)
 		wake_up_process(tsk);
 }
 
-/*
- * If ksoftirqd is scheduled, we do not want to process pending softirqs
-+ * right now. Let ksoftirqd handle this at its own rate, to get fairness.
- */
-static bool ksoftirqd_running(void)
-{
-	struct task_struct *tsk = __this_cpu_read(ksoftirqd);
-
-	if (pending & SOFTIRQ_NOW_MASK)
-		return false;
-	return tsk && task_is_running(tsk) && !__kthread_should_park(tsk);
-}
-
 #ifdef CONFIG_TRACE_IRQFLAGS
 DEFINE_PER_CPU(int, hardirqs_enabled);
 DEFINE_PER_CPU(int, hardirq_context);
@@ -244,7 +231,7 @@ void __local_bh_enable_ip(unsigned long ip, unsigned int cnt)
 		goto out;
 
 	pending = local_softirq_pending();
-	if (!pending || ksoftirqd_running())
+	if (!pending)
 		goto out;
 
 	/*
@@ -427,9 +414,6 @@ static inline bool should_wake_ksoftirqd(void)
 
 static inline void invoke_softirq(void)
 {
-	if (ksoftirqd_running())
-		return;
-
 	if (!force_irqthreads() || !__this_cpu_read(ksoftirqd)) {
 #ifdef CONFIG_HAVE_IRQ_EXIT_ON_IRQ_STACK
 		/*
@@ -463,7 +447,7 @@ asmlinkage __visible void do_softirq(void)
 
 	pending = local_softirq_pending();
 
-	if (pending && !ksoftirqd_running())
+	if (pending)
 		do_softirq_own_stack();
 
 	local_irq_restore(flags);