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 13:13:39 +0530 Subject: [PATCH v5 38/45] parisc: 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: <20130122074335.13822.41002.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: "James E.J. Bottomley" Cc: linux-parisc at vger.kernel.org Signed-off-by: Srivatsa S. Bhat --- arch/parisc/kernel/smp.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/parisc/kernel/smp.c b/arch/parisc/kernel/smp.c index 6266730..f7851b7 100644 --- a/arch/parisc/kernel/smp.c +++ b/arch/parisc/kernel/smp.c @@ -229,11 +229,13 @@ static inline void send_IPI_allbutself(enum ipi_message_type op) { int i; - + + get_online_cpus_atomic(); for_each_online_cpu(i) { if (i != smp_processor_id()) send_IPI_single(i, op); } + put_online_cpus_atomic(); }