On Sun, Jun 23, 2013 at 07:13:33PM +0530, Srivatsa S. Bhat wrote:
> 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>
> #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();
Does this driver really need to be doing this in the first place? If
so, why? The majority of network drivers don't, why is this one
"special"?
thanks,
greg k-h
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