[PATCH 6/9] softirq: Provide a softirq_needs_break() API

[Liu Jian]

From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>

So that all open_softirq() users can employ the same break conditions
and work off the same time-base in case of multiple pending vectors.

Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Signed-off-by: Liu Jian <liujian56@xxxxxxxxxx>
---
 include/linux/interrupt.h |  5 +++++
 kernel/softirq.c          | 16 ++++++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index a92bce40b04b..94d1047fe0c3 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -584,8 +584,13 @@ extern const char * const softirq_to_name[NR_SOFTIRQS];
 struct softirq_action
 {
 	void	(*action)(struct softirq_action *);
+	u64	start;
+	u64	timo;
 };
 
+extern struct softirq_action softirq_action_now(void);
+extern bool softirq_needs_break(struct softirq_action *action);
+
 asmlinkage void do_softirq(void);
 asmlinkage void __do_softirq(void);
 
diff --git a/kernel/softirq.c b/kernel/softirq.c
index baa08ae1604f..dc4299e40dad 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -533,6 +533,20 @@ static inline bool __softirq_needs_break(u64 start, u64 timo)
 	return false;
 }
 
+bool softirq_needs_break(struct softirq_action *h)
+{
+	return __softirq_needs_break(h->start, h->timo);
+}
+
+struct softirq_action softirq_action_now(void)
+{
+	struct softirq_action h = {
+		.start = sched_clock(),
+		.timo = MAX_SOFTIRQ_TIME,
+	};
+	return h;
+}
+
 asmlinkage __visible void __softirq_entry __do_softirq(void)
 {
 	unsigned int max_restart = MAX_SOFTIRQ_RESTART;
@@ -572,6 +586,8 @@ asmlinkage __visible void __softirq_entry __do_softirq(void)
 		__clear_bit(vec_nr, &pending);
 
 		h = softirq_vec + vec_nr;
+		h->start = start;
+		h->timo = timo;
 
 		prev_count = preempt_count();
 
-- 
2.34.1