[PATCH 25/45] staging/octeon: Use get/put_online_cpus_atomic() to prevent CPU offline

[Srivatsa S. Bhat]

Once stop_machine() is gone from the CPU offline path, we won't be able
to depend on disabling preemption 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: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
Cc: devel at driverdev.osuosl.org
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat at linux.vnet.ibm.com>
---

 drivers/staging/octeon/ethernet-rx.c |    3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/staging/octeon/ethernet-rx.c b/drivers/staging/octeon/ethernet-rx.c
index 34afc16..8588b4d 100644
--- a/drivers/staging/octeon/ethernet-rx.c
+++ b/drivers/staging/octeon/ethernet-rx.c
@@ -36,6 +36,7 @@
 #include <linux/prefetch.h>
 #include <linux/ratelimit.h>
 #include <linux/smp.h>
+#include <linux/cpu.h>
 #include <linux/interrupt.h>
 #include <net/dst.h>
 #ifdef CONFIG_XFRM
@@ -97,6 +98,7 @@ static void cvm_oct_enable_one_cpu(void)
 		return;
 
 	/* ... if a CPU is available, Turn on NAPI polling for that CPU.  */
+	get_online_cpus_atomic();
 	for_each_online_cpu(cpu) {
 		if (!cpu_test_and_set(cpu, core_state.cpu_state)) {
 			v = smp_call_function_single(cpu, cvm_oct_enable_napi,
@@ -106,6 +108,7 @@ static void cvm_oct_enable_one_cpu(void)
 			break;
 		}
 	}
+	put_online_cpus_atomic();
 }
 
 static void cvm_oct_no_more_work(void)