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 13:14:35 +0530 Subject: [PATCH v5 42/45] tile: 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: <20130122074430.13822.27480.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: Chris Metcalf Signed-off-by: Srivatsa S. Bhat --- arch/tile/kernel/smp.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/tile/kernel/smp.c b/arch/tile/kernel/smp.c index cbc73a8..fb30624 100644 --- a/arch/tile/kernel/smp.c +++ b/arch/tile/kernel/smp.c @@ -15,6 +15,7 @@ */ #include +#include #include #include #include @@ -82,9 +83,12 @@ void send_IPI_many(const struct cpumask *mask, int tag) void send_IPI_allbutself(int tag) { struct cpumask mask; + + get_online_cpus_atomic(); cpumask_copy(&mask, cpu_online_mask); cpumask_clear_cpu(smp_processor_id(), &mask); send_IPI_many(&mask, tag); + put_online_cpus_atomic(); } /*