Re: [PATCH RT] sched: let softirq_count() return !0 if inside local_bh_disable()ed section
From: Steven Rostedt <rostedt@goodmis.org>
Date: 2018-05-22 15:53:15
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On Thu, 17 May 2018 12:22:14 +0200 Sebastian Andrzej Siewior [off-list ref] wrote:
I don't see a reason why softirq_count() shouldn't reflect the fact that we are within a local_bh_disable() section. I *think* it was done primary because in RT the softirq is slightly different (and preemptible) and it broke some of RCU's assumptions. I don't see any fallout with this change. Furthermore, all checks like "WARN_ON(!softirq_count())" will work and we can drop the workaround we currently have in the queue.
Looks to keep the paradigm closer to vanilla Linux to me. Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org> -- Steve
quoted hunk ↗ jump to hunk
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> --- include/linux/preempt.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)diff --git a/include/linux/preempt.h b/include/linux/preempt.h index 0591df500e9d..d8c05a2626ca 100644 --- a/include/linux/preempt.h +++ b/include/linux/preempt.h@@ -91,7 +91,7 @@ # define softirq_count() (preempt_count() & SOFTIRQ_MASK) # define in_serving_softirq() (softirq_count() & SOFTIRQ_OFFSET) #else -# define softirq_count() (0UL) +# define softirq_count() (current->softirq_nestcnt) extern int in_serving_softirq(void); #endif