From mboxrd@z Thu Jan 1 00:00:00 1970 From: srivatsa.bhat@linux.vnet.ibm.com (Srivatsa S. Bhat) Date: Tue, 22 Jan 2013 13:11:26 +0530 Subject: [PATCH v5 31/45] blackfin/smp: Use get/put_online_cpus_atomic() to prevent CPU offline In-Reply-To: <20130122073210.13822.50434.stgit@srivatsabhat.in.ibm.com> References: <20130122073210.13822.50434.stgit@srivatsabhat.in.ibm.com> Message-ID: <20130122074123.13822.39102.stgit@srivatsabhat.in.ibm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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: Mike Frysinger Cc: Bob Liu Cc: Steven Miao Cc: uclinux-dist-devel at blackfin.uclinux.org Signed-off-by: Srivatsa S. Bhat --- arch/blackfin/mach-common/smp.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/arch/blackfin/mach-common/smp.c b/arch/blackfin/mach-common/smp.c index bb61ae4..6cc6d7a 100644 --- a/arch/blackfin/mach-common/smp.c +++ b/arch/blackfin/mach-common/smp.c @@ -194,6 +194,7 @@ void send_ipi(const struct cpumask *cpumask, enum ipi_message_type msg) struct ipi_data *bfin_ipi_data; unsigned long flags; + get_online_cpus_atomic(); local_irq_save(flags); smp_mb(); for_each_cpu(cpu, cpumask) { @@ -205,6 +206,7 @@ void send_ipi(const struct cpumask *cpumask, enum ipi_message_type msg) } local_irq_restore(flags); + put_online_cpus_atomic(); } void arch_send_call_function_single_ipi(int cpu) @@ -238,13 +240,13 @@ void smp_send_stop(void) { cpumask_t callmap; - preempt_disable(); + get_online_cpus_atomic(); cpumask_copy(&callmap, cpu_online_mask); cpumask_clear_cpu(smp_processor_id(), &callmap); if (!cpumask_empty(&callmap)) send_ipi(&callmap, BFIN_IPI_CPU_STOP); - preempt_enable(); + put_online_cpus_atomic(); return; }