Commit 82b691be authored by Ingo Molnar's avatar Ingo Molnar Committed by Thomas Gleixner
Browse files

softirq: Consolidate common code in tasklet_[hi]_action() 



tasklet_action() + tasklet_hi_action() are almost identical.  Move the
common code from both function into __tasklet_action_common() and let
both functions invoke it with different arguments.

[ bigeasy: Splitted out from RT's "tasklet: Prevent tasklets from going
	   into infinite spin in RT" and added commit message]

Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Julia Cartwright <juliac@eso.teric.us>
Link: https://lkml.kernel.org/r/20180227164808.10093-3-bigeasy@linutronix.de
parent 6498ddad

kernel/softirq.c

+15 −39
Original line number Diff line number Diff line
@@ -490,14 +490,16 @@ void __tasklet_hi_schedule(struct tasklet_struct *t) 
}

EXPORT_SYMBOL(__tasklet_hi_schedule);



static __latent_entropy void tasklet_action(struct softirq_action *a)

static void tasklet_action_common(struct softirq_action *a,

				  struct tasklet_head *tl_head,

				  unsigned int softirq_nr)

{

	struct tasklet_struct *list;



	local_irq_disable();

	list = __this_cpu_read(tasklet_vec.head);

	__this_cpu_write(tasklet_vec.head, NULL);

	__this_cpu_write(tasklet_vec.tail, this_cpu_ptr(&tasklet_vec.head));

	list = tl_head->head;

	tl_head->head = NULL;

	tl_head->tail = &tl_head->head;

	local_irq_enable();



	while (list) {
@@ -519,47 +521,21 @@ static __latent_entropy void tasklet_action(struct softirq_action *a) 


		local_irq_disable();

		t->next = NULL;

		*__this_cpu_read(tasklet_vec.tail) = t;

		__this_cpu_write(tasklet_vec.tail, &(t->next));

		__raise_softirq_irqoff(TASKLET_SOFTIRQ);

		*tl_head->tail = t;

		tl_head->tail = &t->next;

		__raise_softirq_irqoff(softirq_nr);

		local_irq_enable();

	}

}



static __latent_entropy void tasklet_hi_action(struct softirq_action *a)

static __latent_entropy void tasklet_action(struct softirq_action *a)

{

	struct tasklet_struct *list;



	local_irq_disable();

	list = __this_cpu_read(tasklet_hi_vec.head);

	__this_cpu_write(tasklet_hi_vec.head, NULL);

	__this_cpu_write(tasklet_hi_vec.tail, this_cpu_ptr(&tasklet_hi_vec.head));

	local_irq_enable();



	while (list) {

		struct tasklet_struct *t = list;



		list = list->next;



		if (tasklet_trylock(t)) {

			if (!atomic_read(&t->count)) {

				if (!test_and_clear_bit(TASKLET_STATE_SCHED,

							&t->state))

					BUG();

				t->func(t->data);

				tasklet_unlock(t);

				continue;

			}

			tasklet_unlock(t);

	tasklet_action_common(a, this_cpu_ptr(&tasklet_vec), TASKLET_SOFTIRQ);

}



		local_irq_disable();

		t->next = NULL;

		*__this_cpu_read(tasklet_hi_vec.tail) = t;

		__this_cpu_write(tasklet_hi_vec.tail, &(t->next));

		__raise_softirq_irqoff(HI_SOFTIRQ);

		local_irq_enable();

	}

static __latent_entropy void tasklet_hi_action(struct softirq_action *a)

{

	tasklet_action_common(a, this_cpu_ptr(&tasklet_hi_vec), HI_SOFTIRQ);

}



void tasklet_init(struct tasklet_struct *t,

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