On 06/23/2013 11:47 PM, Greg Kroah-Hartman wrote:
> 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"?
>
Honestly, I don't know. Let's CC the author of that code (David Daney).
I wonder why get_maintainer.pl didn't generate his name for this file,
even though the entire file is almost made up of his commits alone!
Regards,
Srivatsa S. Bhat
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