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

From: Srivatsa S. Bhat
Date: Sun Jun 23 2013 - 09:48:07 EST

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@xxxxxxxxxxxxxxxxxxx>
Cc: devel@xxxxxxxxxxxxxxxxxxxx
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@xxxxxxxxxxxxxxxxxx>

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>
@@ -97,6 +98,7 @@ static void cvm_oct_enable_one_cpu(void)

/* ... 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)
+ put_online_cpus_atomic();

static void cvm_oct_no_more_work(void)

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