Messages in this thread Patch in this message | | | From | "Srivatsa S. Bhat" <> | Subject | [PATCH v6 21/46] block: Use get/put_online_cpus_atomic() to prevent CPU offline | Date | Mon, 18 Feb 2013 18:11:10 +0530 |
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Once stop_machine() is gone from the CPU offline path, we won't be able to depend on preempt_disable() or local_irq_disable() 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 <srivatsa.bhat@linux.vnet.ibm.com> ---
block/blk-softirq.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/block/blk-softirq.c b/block/blk-softirq.c index 467c8de..448f9a9 100644 --- a/block/blk-softirq.c +++ b/block/blk-softirq.c @@ -58,6 +58,8 @@ 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; @@ -66,9 +68,11 @@ 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; } #else /* CONFIG_SMP && CONFIG_USE_GENERIC_SMP_HELPERS */
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