| From | "Srivatsa S. Bhat" <> | Subject | [PATCH v5 17/45] softirq: Use get/put_online_cpus_atomic() to prevent CPU offline | Date | Tue, 22 Jan 2013 13:07:43 +0530 |
| |
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: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> ---
kernel/softirq.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/kernel/softirq.c b/kernel/softirq.c index ed567ba..98c3e27 100644 --- a/kernel/softirq.c +++ b/kernel/softirq.c @@ -631,6 +631,7 @@ static void remote_softirq_receive(void *data) static int __try_remote_softirq(struct call_single_data *cp, int cpu, int softirq) { + get_online_cpus_atomic(); if (cpu_online(cpu)) { cp->func = remote_softirq_receive; cp->info = cp; @@ -638,8 +639,10 @@ static int __try_remote_softirq(struct call_single_data *cp, int cpu, int softir cp->priv = softirq; __smp_call_function_single(cpu, cp, 0); + put_online_cpus_atomic(); return 0; } + put_online_cpus_atomic(); return 1; } #else /* CONFIG_USE_GENERIC_SMP_HELPERS */
|