[PATCH] net: mvneta: Remove superfluous SMP function call

[PATCH] net: mvneta: Remove superfluous SMP function call

[Anna-Maria Gleixner]

Since commit 1cf4f629d9d2 ("cpu/hotplug: Move online calls to
hotplugged cpu") it is ensured that callbacks of CPU_ONLINE and
CPU_DOWN_PREPARE are processed on the hotplugged cpu. Due to this SMP
function calls are no longer required.

Replace smp_call_function_single() with a direct call to
mvneta_percpu_enable() or mvneta_percpu_disable(). The functions do
not require to be called with interrupts disabled, therefore the
smp_call_function_single() calling convention is not preserved.

Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: netdev@vger.kernel.org
Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
---
 drivers/net/ethernet/marvell/mvneta.c |    6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

--- a/drivers/net/ethernet/marvell/mvneta.c
+++ b/drivers/net/ethernet/marvell/mvneta.c
@@ -3354,8 +3354,7 @@ static int mvneta_percpu_notifier(struct
 		/* Enable per-CPU interrupts on the CPU that is
 		 * brought up.
 		 */
-		smp_call_function_single(cpu, mvneta_percpu_enable,
-					 pp, true);
+		mvneta_percpu_enable(pp);
 
 		/* Enable per-CPU interrupt on the one CPU we care
 		 * about.
@@ -3387,8 +3386,7 @@ static int mvneta_percpu_notifier(struct
 		/* Disable per-CPU interrupts on the CPU that is
 		 * brought down.
 		 */
-		smp_call_function_single(cpu, mvneta_percpu_disable,
-					 pp, true);
+		mvneta_percpu_disable(pp);
 
 		break;
 	case CPU_DEAD:

Re: [PREEMPT-RT] [PATCH] net: mvneta: Remove superfluous SMP function call

[Anna-Maria Gleixner]

On Mon, 4 Apr 2016, Anna-Maria Gleixner wrote:

> Since commit 1cf4f629d9d2 ("cpu/hotplug: Move online calls to
> hotplugged cpu") it is ensured that callbacks of CPU_ONLINE and
> CPU_DOWN_PREPARE are processed on the hotplugged cpu. Due to this SMP
> function calls are no longer required.
> 
> Replace smp_call_function_single() with a direct call to
> mvneta_percpu_enable() or mvneta_percpu_disable(). The functions do
> not require to be called with interrupts disabled, therefore the
> smp_call_function_single() calling convention is not preserved.
> 
> Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
> Cc: netdev@vger.kernel.org
> Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
> ---
>  drivers/net/ethernet/marvell/mvneta.c |    6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
>

Please do not queue it. Heiko Carstens pointed out a problem: It isn't
ensured, that the callbacks of CPU_DOWN_FAILED are always processed on
the CPU that failed in CPU_DOWN_PREPARE (see
http://marc.info/?l=linux-s390&m=145985621421250&w=2 ). Once this
issue is fixed, I will resend the patch.

Anna-Maria