1 files changed, 24 insertions, 25 deletions

diff --git a/kernel/softirq.c b/kernel/softirq.c
index 17caf4b63342..744fa611cae0 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -58,7 +58,7 @@ static struct softirq_action softirq_vec[NR_SOFTIRQS] __cacheline_aligned_in_smp
 DEFINE_PER_CPU(struct task_struct *, ksoftirqd);
 
 const char * const softirq_to_name[NR_SOFTIRQS] = {
-        "HI", "TIMER", "NET_TX", "NET_RX", "BLOCK", "BLOCK_IOPOLL",
+        "HI", "TIMER", "NET_TX", "NET_RX", "BLOCK", "IRQ_POLL",
         "TASKLET", "SCHED", "HRTIMER", "RCU"
 };
 
@@ -78,6 +78,17 @@ static void wakeup_softirqd(void)
 }
 
 /*
+ * 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);
+
+        return tsk && (tsk->state == TASK_RUNNING);
+}
+
+/*
  * preempt_count and SOFTIRQ_OFFSET usage:
  * - preempt_count is changed by SOFTIRQ_OFFSET on entering or leaving
  *   softirq processing.
@@ -313,7 +324,7 @@ asmlinkage __visible void do_softirq(void)
 
         pending = local_softirq_pending();
 
-        if (pending)
+        if (pending && !ksoftirqd_running())
                 do_softirq_own_stack();
 
         local_irq_restore(flags);
@@ -340,6 +351,9 @@ void irq_enter(void)
 
 static inline void invoke_softirq(void)
 {
+        if (ksoftirqd_running())
+                return;
+
         if (!force_irqthreads) {
 #ifdef CONFIG_HAVE_IRQ_EXIT_ON_IRQ_STACK
                 /*
@@ -482,7 +496,7 @@ void __tasklet_hi_schedule_first(struct tasklet_struct *t)
 }
 EXPORT_SYMBOL(__tasklet_hi_schedule_first);
 
-static void tasklet_action(struct softirq_action *a)
+static __latent_entropy void tasklet_action(struct softirq_action *a)
 {
         struct tasklet_struct *list;
 
@@ -518,7 +532,7 @@ static void tasklet_action(struct softirq_action *a)
         }
 }
 
-static void tasklet_hi_action(struct softirq_action *a)
+static __latent_entropy void tasklet_hi_action(struct softirq_action *a)
 {
         struct tasklet_struct *list;
 
@@ -700,7 +714,7 @@ void tasklet_kill_immediate(struct tasklet_struct *t, unsigned int cpu)
         BUG();
 }
 
-static void takeover_tasklets(unsigned int cpu)
+static int takeover_tasklets(unsigned int cpu)
 {
         /* CPU is dead, so no lock needed. */
         local_irq_disable();
@@ -723,27 +737,12 @@ static void takeover_tasklets(unsigned int cpu)
         raise_softirq_irqoff(HI_SOFTIRQ);
 
         local_irq_enable();
+        return 0;
 }
+#else
+#define takeover_tasklets       NULL
 #endif /* CONFIG_HOTPLUG_CPU */
 
-static int cpu_callback(struct notifier_block *nfb, unsigned long action,
-                        void *hcpu)
-{
-        switch (action) {
-#ifdef CONFIG_HOTPLUG_CPU
-        case CPU_DEAD:
-        case CPU_DEAD_FROZEN:
-                takeover_tasklets((unsigned long)hcpu);
-                break;
-#endif /* CONFIG_HOTPLUG_CPU */
-        }
-        return NOTIFY_OK;
-}
-
-static struct notifier_block cpu_nfb = {
-        .notifier_call = cpu_callback
-};
-
 static struct smp_hotplug_thread softirq_threads = {
         .store                  = &ksoftirqd,
         .thread_should_run      = ksoftirqd_should_run,
@@ -753,8 +752,8 @@ static struct smp_hotplug_thread softirq_threads = {
 
 static __init int spawn_ksoftirqd(void)
 {
-        register_cpu_notifier(&cpu_nfb);
-
+        cpuhp_setup_state_nocalls(CPUHP_SOFTIRQ_DEAD, "softirq:dead", NULL,
+                                  takeover_tasklets);
         BUG_ON(smpboot_register_percpu_thread(&softirq_threads));
 
         return 0;