[PATCH v3 22/45] block: Use get/put_online_cpus_atomic() to prevent CPU offline
From: Srivatsa S. Bhat <hidden>
Date: 2013-06-27 20:00:05
Also in:
linux-arch, linux-pm, lkml, netdev
Subsystem:
block layer, the rest · Maintainers:
Jens Axboe, Linus Torvalds
Once stop_machine() is gone from the CPU offline path, we won't be able to depend on disabling preemption to prevent CPUs from going offline from under us. Use the get/put_online_cpus_atomic() APIs to prevent CPUs from going offline, while invoking from atomic context. Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Srivatsa S. Bhat <redacted> --- block/blk-softirq.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/block/blk-softirq.c b/block/blk-softirq.c
index 467c8de..bbab3d3 100644
--- a/block/blk-softirq.c
+++ b/block/blk-softirq.c@@ -58,6 +58,7 @@ static void trigger_softirq(void *data) */ static int raise_blk_irq(int cpu, struct request *rq) { + get_online_cpus_atomic(); if (cpu_online(cpu)) { struct call_single_data *data = &rq->csd;
@@ -66,8 +67,10 @@ static int raise_blk_irq(int cpu, struct request *rq) data->flags = 0; __smp_call_function_single(cpu, data, 0); + put_online_cpus_atomic(); return 0; } + put_online_cpus_atomic(); return 1; }