[tip:smp/hotplug] block/softirq: Convert to hotplug state machine

tip-bot for Sebastian Andrzej Siewior
2016-09-19T19:55:41Z

Commit-ID: 9a659f43dfea27cca423d4e80809be447f4c9ce7
Gitweb: http://git.kernel.org/tip/9a659f43dfea27cca423d4e80809be447f4c9ce7
Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
AuthorDate: Tue, 6 Sep 2016 19:04:44 +0200
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitDate: Mon, 19 Sep 2016 21:44:28 +0200

block/softirq: Convert to hotplug state machine

Install the callbacks via the state machine.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20160906170457.32393-9-bigeasy@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

---
block/blk-softirq.c | 27 ++++++++++-----------------
include/linux/cpuhotplug.h | 1 +
2 files changed, 11 insertions(+), 17 deletions(-)

diff --git a/block/blk-softirq.c b/block/blk-softirq.c
index 53b1737..96631e6 100644
--- a/block/blk-softirq.c
+++ b/block/blk-softirq.c
@@ -78,30 +78,21 @@ static int raise_blk_irq(int cpu, struct request *rq)
}
#endif

-static int blk_cpu_notify(struct notifier_block *self, unsigned long action,
- void *hcpu)
+static int blk_softirq_cpu_dead(unsigned int cpu)
{
/*
* If a CPU goes away, splice its entries to the current CPU
* and trigger a run of the softirq
*/
- if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) {
- int cpu = (unsigned long) hcpu;
-
- local_irq_disable();
- list_splice_init(&per_cpu(blk_cpu_done, cpu),
- this_cpu_ptr(&blk_cpu_done));
- raise_softirq_irqoff(BLOCK_SOFTIRQ);
- local_irq_enable();
- }
+ local_irq_disable();
+ list_splice_init(&per_cpu(blk_cpu_done, cpu),
+ this_cpu_ptr(&blk_cpu_done));
+ raise_softirq_irqoff(BLOCK_SOFTIRQ);
+ local_irq_enable();

- return NOTIFY_OK;
+ return 0;
}

-static struct notifier_block blk_cpu_notifier = {
- .notifier_call = blk_cpu_notify,
-};
-
void __blk_complete_request(struct request *req)
{
int ccpu, cpu;
@@ -180,7 +171,9 @@ static __init int blk_softirq_init(void)
INIT_LIST_HEAD(&per_cpu(blk_cpu_done, i));

open_softirq(BLOCK_SOFTIRQ, blk_done_softirq);
- register_hotcpu_notifier(&blk_cpu_notifier);
+ cpuhp_setup_state_nocalls(CPUHP_BLOCK_SOFTIRQ_DEAD,
+ "block/softirq:dead", NULL,
+ blk_softirq_cpu_dead);
return 0;
}
subsys_initcall(blk_softirq_init);
diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 2ca7b34..d4274d5 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -23,6 +23,7 @@ enum cpuhp_state {
CPUHP_ARM64_FPSIMD_DEAD,
CPUHP_ARM_OMAP_WAKE_DEAD,
CPUHP_IRQ_POLL_DEAD,
+ CPUHP_BLOCK_SOFTIRQ_DEAD,
CPUHP_WORKQUEUE_PREP,
CPUHP_POWER_NUMA_PREPARE,
CPUHP_HRTIMERS_PREPARE,