[RFC PATCH] powerpc/pseries/mobility: notify network peers after migration

[RFC PATCH] powerpc/pseries/mobility: notify network peers after migration

[Thomas Falcon]

After a migration, it is necessary to send a gratuitous ARP
from all running interfaces so that the rest of the network
is aware of its new location. However, some supported network
devices are unaware that they have been migrated. To avoid network
interruptions and other unwanted behavior, force a GARP on all
valid, running interfaces as part of the post_mobility_fixup
routine.

Signed-off-by: Thomas Falcon <tlfalcon@linux.ibm.com>
---
 arch/powerpc/platforms/pseries/mobility.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/arch/powerpc/platforms/pseries/mobility.c b/arch/powerpc/platforms/pseries/mobility.c
index b571285f6c14..c1abc14cf2bb 100644
--- a/arch/powerpc/platforms/pseries/mobility.c
+++ b/arch/powerpc/platforms/pseries/mobility.c
@@ -17,6 +17,9 @@
 #include <linux/delay.h>
 #include <linux/slab.h>
 #include <linux/stringify.h>
+#include <linux/netdevice.h>
+#include <linux/rtnetlink.h>
+#include <net/net_namespace.h>
 
 #include <asm/machdep.h>
 #include <asm/rtas.h>
@@ -331,6 +334,8 @@ void post_mobility_fixup(void)
 {
 	int rc;
 	int activate_fw_token;
+	struct net_device *netdev;
+	struct net *net;
 
 	activate_fw_token = rtas_token("ibm,activate-firmware");
 	if (activate_fw_token == RTAS_UNKNOWN_SERVICE) {
@@ -371,6 +376,21 @@ void post_mobility_fixup(void)
 	/* Possibly switch to a new RFI flush type */
 	pseries_setup_rfi_flush();
 
+	/* need to force a gratuitous ARP on running interfaces */
+	rtnl_lock();
+	for_each_net(net) {
+		for_each_netdev(net, netdev) {
+			if (netif_device_present(netdev) &&
+			    netif_running(netdev) &&
+			    !(netdev->flags & (IFF_NOARP | IFF_LOOPBACK)))
+				call_netdevice_notifiers(NETDEV_NOTIFY_PEERS,
+							 netdev);
+				call_netdevice_notifiers(NETDEV_RESEND_IGMP,
+							 netdev);
+		}
+	}
+	rtnl_unlock();
+
 	return;
 }
 
-- 
2.12.3

[RFC PATCH] powerpc/pseries/mobility: notify network peers after migration

[Thomas Falcon]

After a migration, it is necessary to send a gratuitous ARP
from all running interfaces so that the rest of the network
is aware of its new location. However, some supported network
devices are unaware that they have been migrated. To avoid network
interruptions and other unwanted behavior, force a GARP on all
valid, running interfaces as part of the post_mobility_fixup
routine.

Signed-off-by: Thomas Falcon <tlfalcon@linux.ibm.com>
---
 arch/powerpc/platforms/pseries/mobility.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/arch/powerpc/platforms/pseries/mobility.c b/arch/powerpc/platforms/pseries/mobility.c
index b571285f6c14..c1abc14cf2bb 100644
--- a/arch/powerpc/platforms/pseries/mobility.c
+++ b/arch/powerpc/platforms/pseries/mobility.c
@@ -17,6 +17,9 @@
 #include <linux/delay.h>
 #include <linux/slab.h>
 #include <linux/stringify.h>
+#include <linux/netdevice.h>
+#include <linux/rtnetlink.h>
+#include <net/net_namespace.h>
 
 #include <asm/machdep.h>
 #include <asm/rtas.h>
@@ -331,6 +334,8 @@ void post_mobility_fixup(void)
 {
 	int rc;
 	int activate_fw_token;
+	struct net_device *netdev;
+	struct net *net;
 
 	activate_fw_token = rtas_token("ibm,activate-firmware");
 	if (activate_fw_token == RTAS_UNKNOWN_SERVICE) {
@@ -371,6 +376,21 @@ void post_mobility_fixup(void)
 	/* Possibly switch to a new RFI flush type */
 	pseries_setup_rfi_flush();
 
+	/* need to force a gratuitous ARP on running interfaces */
+	rtnl_lock();
+	for_each_net(net) {
+		for_each_netdev(net, netdev) {
+			if (netif_device_present(netdev) &&
+			    netif_running(netdev) &&
+			    !(netdev->flags & (IFF_NOARP | IFF_LOOPBACK)))
+				call_netdevice_notifiers(NETDEV_NOTIFY_PEERS,
+							 netdev);
+				call_netdevice_notifiers(NETDEV_RESEND_IGMP,
+							 netdev);
+		}
+	}
+	rtnl_unlock();
+
 	return;
 }
 
-- 
2.12.3

Re: [RFC PATCH] powerpc/pseries/mobility: notify network peers after migration

[Russell Currey]

On Tue, 2019-11-05 at 18:06 -0600, Thomas Falcon wrote:
> After a migration, it is necessary to send a gratuitous ARP
> from all running interfaces so that the rest of the network
> is aware of its new location. However, some supported network
> devices are unaware that they have been migrated. To avoid network
> interruptions and other unwanted behavior, force a GARP on all
> valid, running interfaces as part of the post_mobility_fixup
> routine.
> 
> Signed-off-by: Thomas Falcon <tlfalcon@linux.ibm.com>

Hi Thomas,

> ---
>  arch/powerpc/platforms/pseries/mobility.c | 20 ++++++++++++++++++++
>  1 file changed, 20 insertions(+)
> 
> diff --git a/arch/powerpc/platforms/pseries/mobility.c
> b/arch/powerpc/platforms/pseries/mobility.c
> index b571285f6c14..c1abc14cf2bb 100644
> --- a/arch/powerpc/platforms/pseries/mobility.c
> +++ b/arch/powerpc/platforms/pseries/mobility.c
> @@ -17,6 +17,9 @@
>  #include <linux/delay.h>
>  #include <linux/slab.h>
>  #include <linux/stringify.h>
> +#include <linux/netdevice.h>
> +#include <linux/rtnetlink.h>
> +#include <net/net_namespace.h>
>  
>  #include <asm/machdep.h>
>  #include <asm/rtas.h>
> @@ -331,6 +334,8 @@ void post_mobility_fixup(void)
>  {
>  	int rc;
>  	int activate_fw_token;
> +	struct net_device *netdev;
> +	struct net *net;
>  
>  	activate_fw_token = rtas_token("ibm,activate-firmware");
>  	if (activate_fw_token == RTAS_UNKNOWN_SERVICE) {
> @@ -371,6 +376,21 @@ void post_mobility_fixup(void)
>  	/* Possibly switch to a new RFI flush type */
>  	pseries_setup_rfi_flush();
>  
> +	/* need to force a gratuitous ARP on running interfaces */
> +	rtnl_lock();
> +	for_each_net(net) {
> +		for_each_netdev(net, netdev) {
> +			if (netif_device_present(netdev) &&
> +			    netif_running(netdev) &&
> +			    !(netdev->flags & (IFF_NOARP |
> IFF_LOOPBACK)))
> +				call_netdevice_notifiers(NETDEV_NOTIFY_
> PEERS,
> +							 netdev);

Without curly braces following the "if" statment, the second line
(below) will be executed unconditionally, which I assume with this
indentation isn't what you want.

(reported by snowpatch)

- Russell

> +				call_netdevice_notifiers(NETDEV_RESEND_
> IGMP,
> +							 netdev);
> +		}
> +	}
> +	rtnl_unlock();
> +
>  	return;
>  }
>  

Re: [RFC PATCH] powerpc/pseries/mobility: notify network peers after migration

[Thomas Falcon]

On 11/5/19 10:13 PM, Russell Currey wrote:
> On Tue, 2019-11-05 at 18:06 -0600, Thomas Falcon wrote:
>> After a migration, it is necessary to send a gratuitous ARP
>> from all running interfaces so that the rest of the network
>> is aware of its new location. However, some supported network
>> devices are unaware that they have been migrated. To avoid network
>> interruptions and other unwanted behavior, force a GARP on all
>> valid, running interfaces as part of the post_mobility_fixup
>> routine.
>>
>> Signed-off-by: Thomas Falcon <tlfalcon@linux.ibm.com>
> Hi Thomas,
>
>> ---
>>   arch/powerpc/platforms/pseries/mobility.c | 20 ++++++++++++++++++++
>>   1 file changed, 20 insertions(+)
>>
>> diff --git a/arch/powerpc/platforms/pseries/mobility.c
>> b/arch/powerpc/platforms/pseries/mobility.c
>> index b571285f6c14..c1abc14cf2bb 100644
>> --- a/arch/powerpc/platforms/pseries/mobility.c
>> +++ b/arch/powerpc/platforms/pseries/mobility.c
>> @@ -17,6 +17,9 @@
>>   #include <linux/delay.h>
>>   #include <linux/slab.h>
>>   #include <linux/stringify.h>
>> +#include <linux/netdevice.h>
>> +#include <linux/rtnetlink.h>
>> +#include <net/net_namespace.h>
>>   
>>   #include <asm/machdep.h>
>>   #include <asm/rtas.h>
>> @@ -331,6 +334,8 @@ void post_mobility_fixup(void)
>>   {
>>   	int rc;
>>   	int activate_fw_token;
>> +	struct net_device *netdev;
>> +	struct net *net;
>>   
>>   	activate_fw_token = rtas_token("ibm,activate-firmware");
>>   	if (activate_fw_token == RTAS_UNKNOWN_SERVICE) {
>> @@ -371,6 +376,21 @@ void post_mobility_fixup(void)
>>   	/* Possibly switch to a new RFI flush type */
>>   	pseries_setup_rfi_flush();
>>   
>> +	/* need to force a gratuitous ARP on running interfaces */
>> +	rtnl_lock();
>> +	for_each_net(net) {
>> +		for_each_netdev(net, netdev) {
>> +			if (netif_device_present(netdev) &&
>> +			    netif_running(netdev) &&
>> +			    !(netdev->flags & (IFF_NOARP |
>> IFF_LOOPBACK)))
>> +				call_netdevice_notifiers(NETDEV_NOTIFY_
>> PEERS,
>> +							 netdev);
> Without curly braces following the "if" statment, the second line
> (below) will be executed unconditionally, which I assume with this
> indentation isn't what you want.
>
> (reported by snowpatch)
>
> - Russell

Thanks for catching that! I'll fix that and send a v2 soon.

Tom


>> +				call_netdevice_notifiers(NETDEV_RESEND_
>> IGMP,
>> +							 netdev);
>> +		}
>> +	}
>> +	rtnl_unlock();
>> +
>>   	return;
>>   }
>>   

Re: [RFC PATCH] powerpc/pseries/mobility: notify network peers after migration

[Nathan Lynch]

Hi Tom,

Thomas Falcon <tlfalcon@linux.ibm.com> writes:
> After a migration, it is necessary to send a gratuitous ARP
> from all running interfaces so that the rest of the network
> is aware of its new location. However, some supported network
> devices are unaware that they have been migrated. To avoid network
> interruptions and other unwanted behavior, force a GARP on all
> valid, running interfaces as part of the post_mobility_fixup
> routine.

[...]

> @@ -331,6 +334,8 @@ void post_mobility_fixup(void)
>  {
>  	int rc;
>  	int activate_fw_token;
> +	struct net_device *netdev;
> +	struct net *net;
>  
>  	activate_fw_token = rtas_token("ibm,activate-firmware");
>  	if (activate_fw_token == RTAS_UNKNOWN_SERVICE) {
> @@ -371,6 +376,21 @@ void post_mobility_fixup(void)
>  	/* Possibly switch to a new RFI flush type */
>  	pseries_setup_rfi_flush();
>  
> +	/* need to force a gratuitous ARP on running interfaces */
> +	rtnl_lock();
> +	for_each_net(net) {
> +		for_each_netdev(net, netdev) {
> +			if (netif_device_present(netdev) &&
> +			    netif_running(netdev) &&
> +			    !(netdev->flags & (IFF_NOARP | IFF_LOOPBACK)))
> +				call_netdevice_notifiers(NETDEV_NOTIFY_PEERS,
> +							 netdev);
> +				call_netdevice_notifiers(NETDEV_RESEND_IGMP,
> +							 netdev);
> +		}
> +	}
> +	rtnl_unlock();
> +

This isn't an outright nak, but this is not nice. It illustrates the
need to rethink the pseries partition migration code. There is no
mechanism for drivers and other interested code to prepare for a
migration or to adjust to the destination. So post_mobility_fixup() will
continue to grow into a fragile collection of calls into unrelated
subsystems until there is a better design -- either a pseries-specific
notification/callback mechanism, or something based on the pm framework.

My understanding is that this is needed specifically for ibmveth and,
unlike ibmvnic, the platform does not provide any notification to that
driver that a migration has occurred, right?

Re: [RFC PATCH] powerpc/pseries/mobility: notify network peers after migration

[Nathan Lynch]

Hi Tom,

Thomas Falcon <tlfalcon@linux.ibm.com> writes:
> After a migration, it is necessary to send a gratuitous ARP
> from all running interfaces so that the rest of the network
> is aware of its new location. However, some supported network
> devices are unaware that they have been migrated. To avoid network
> interruptions and other unwanted behavior, force a GARP on all
> valid, running interfaces as part of the post_mobility_fixup
> routine.

[...]

> @@ -331,6 +334,8 @@ void post_mobility_fixup(void)
>  {
>  	int rc;
>  	int activate_fw_token;
> +	struct net_device *netdev;
> +	struct net *net;
>  
>  	activate_fw_token = rtas_token("ibm,activate-firmware");
>  	if (activate_fw_token == RTAS_UNKNOWN_SERVICE) {
> @@ -371,6 +376,21 @@ void post_mobility_fixup(void)
>  	/* Possibly switch to a new RFI flush type */
>  	pseries_setup_rfi_flush();
>  
> +	/* need to force a gratuitous ARP on running interfaces */
> +	rtnl_lock();
> +	for_each_net(net) {
> +		for_each_netdev(net, netdev) {
> +			if (netif_device_present(netdev) &&
> +			    netif_running(netdev) &&
> +			    !(netdev->flags & (IFF_NOARP | IFF_LOOPBACK)))
> +				call_netdevice_notifiers(NETDEV_NOTIFY_PEERS,
> +							 netdev);
> +				call_netdevice_notifiers(NETDEV_RESEND_IGMP,
> +							 netdev);
> +		}
> +	}
> +	rtnl_unlock();
> +

This isn't an outright nak, but this is not nice. It illustrates the
need to rethink the pseries partition migration code. There is no
mechanism for drivers and other interested code to prepare for a
migration or to adjust to the destination. So post_mobility_fixup() will
continue to grow into a fragile collection of calls into unrelated
subsystems until there is a better design -- either a pseries-specific
notification/callback mechanism, or something based on the pm framework.

My understanding is that this is needed specifically for ibmveth and,
unlike ibmvnic, the platform does not provide any notification to that
driver that a migration has occurred, right?

Re: [RFC PATCH] powerpc/pseries/mobility: notify network peers after migration

[Michael Ellerman]

Hi Thomas,

Thomas Falcon <tlfalcon@linux.ibm.com> writes:
> After a migration, it is necessary to send a gratuitous ARP
> from all running interfaces so that the rest of the network
> is aware of its new location. However, some supported network
> devices are unaware that they have been migrated. To avoid network
> interruptions and other unwanted behavior, force a GARP on all
> valid, running interfaces as part of the post_mobility_fixup
> routine.
>
> Signed-off-by: Thomas Falcon <tlfalcon@linux.ibm.com>
> ---
>  arch/powerpc/platforms/pseries/mobility.c | 20 ++++++++++++++++++++
>  1 file changed, 20 insertions(+)

This patch is in powerpc code, but it's doing networking stuff that I
don't really understand.

So I'd like an Ack from Dave or someone else in netdev land before I
merge it.

cheers


> diff --git a/arch/powerpc/platforms/pseries/mobility.c b/arch/powerpc/platforms/pseries/mobility.c
> index b571285f6c14..c1abc14cf2bb 100644
> --- a/arch/powerpc/platforms/pseries/mobility.c
> +++ b/arch/powerpc/platforms/pseries/mobility.c
> @@ -17,6 +17,9 @@
>  #include <linux/delay.h>
>  #include <linux/slab.h>
>  #include <linux/stringify.h>
> +#include <linux/netdevice.h>
> +#include <linux/rtnetlink.h>
> +#include <net/net_namespace.h>
>  
>  #include <asm/machdep.h>
>  #include <asm/rtas.h>
> @@ -331,6 +334,8 @@ void post_mobility_fixup(void)
>  {
>  	int rc;
>  	int activate_fw_token;
> +	struct net_device *netdev;
> +	struct net *net;
>  
>  	activate_fw_token = rtas_token("ibm,activate-firmware");
>  	if (activate_fw_token == RTAS_UNKNOWN_SERVICE) {
> @@ -371,6 +376,21 @@ void post_mobility_fixup(void)
>  	/* Possibly switch to a new RFI flush type */
>  	pseries_setup_rfi_flush();
>  
> +	/* need to force a gratuitous ARP on running interfaces */
> +	rtnl_lock();
> +	for_each_net(net) {
> +		for_each_netdev(net, netdev) {
> +			if (netif_device_present(netdev) &&
> +			    netif_running(netdev) &&
> +			    !(netdev->flags & (IFF_NOARP | IFF_LOOPBACK)))
> +				call_netdevice_notifiers(NETDEV_NOTIFY_PEERS,
> +							 netdev);
> +				call_netdevice_notifiers(NETDEV_RESEND_IGMP,
> +							 netdev);
> +		}
> +	}
> +	rtnl_unlock();
> +
>  	return;
>  }
>  
> -- 
> 2.12.3

Re: [RFC PATCH] powerpc/pseries/mobility: notify network peers after migration

[Thomas Falcon]

On 11/6/19 7:33 PM, Michael Ellerman wrote:
> Hi Thomas,
>
> Thomas Falcon <tlfalcon@linux.ibm.com> writes:
>> After a migration, it is necessary to send a gratuitous ARP
>> from all running interfaces so that the rest of the network
>> is aware of its new location. However, some supported network
>> devices are unaware that they have been migrated. To avoid network
>> interruptions and other unwanted behavior, force a GARP on all
>> valid, running interfaces as part of the post_mobility_fixup
>> routine.
>>
>> Signed-off-by: Thomas Falcon <tlfalcon@linux.ibm.com>
>> ---
>>   arch/powerpc/platforms/pseries/mobility.c | 20 ++++++++++++++++++++
>>   1 file changed, 20 insertions(+)
> This patch is in powerpc code, but it's doing networking stuff that I
> don't really understand.
>
> So I'd like an Ack from Dave or someone else in netdev land before I
> merge it.

Thanks, I've already included netdev in the CC list. I'll wait and keep 
an eye out for any comments from that side.

Tom



>
> cheers
>
>
>> diff --git a/arch/powerpc/platforms/pseries/mobility.c b/arch/powerpc/platforms/pseries/mobility.c
>> index b571285f6c14..c1abc14cf2bb 100644
>> --- a/arch/powerpc/platforms/pseries/mobility.c
>> +++ b/arch/powerpc/platforms/pseries/mobility.c
>> @@ -17,6 +17,9 @@
>>   #include <linux/delay.h>
>>   #include <linux/slab.h>
>>   #include <linux/stringify.h>
>> +#include <linux/netdevice.h>
>> +#include <linux/rtnetlink.h>
>> +#include <net/net_namespace.h>
>>   
>>   #include <asm/machdep.h>
>>   #include <asm/rtas.h>
>> @@ -331,6 +334,8 @@ void post_mobility_fixup(void)
>>   {
>>   	int rc;
>>   	int activate_fw_token;
>> +	struct net_device *netdev;
>> +	struct net *net;
>>   
>>   	activate_fw_token = rtas_token("ibm,activate-firmware");
>>   	if (activate_fw_token == RTAS_UNKNOWN_SERVICE) {
>> @@ -371,6 +376,21 @@ void post_mobility_fixup(void)
>>   	/* Possibly switch to a new RFI flush type */
>>   	pseries_setup_rfi_flush();
>>   
>> +	/* need to force a gratuitous ARP on running interfaces */
>> +	rtnl_lock();
>> +	for_each_net(net) {
>> +		for_each_netdev(net, netdev) {
>> +			if (netif_device_present(netdev) &&
>> +			    netif_running(netdev) &&
>> +			    !(netdev->flags & (IFF_NOARP | IFF_LOOPBACK)))
>> +				call_netdevice_notifiers(NETDEV_NOTIFY_PEERS,
>> +							 netdev);
>> +				call_netdevice_notifiers(NETDEV_RESEND_IGMP,
>> +							 netdev);
>> +		}
>> +	}
>> +	rtnl_unlock();
>> +
>>   	return;
>>   }
>>   
>> -- 
>> 2.12.3

Re: [RFC PATCH] powerpc/pseries/mobility: notify network peers after migration

[Thomas Falcon]

On 11/6/19 4:14 PM, Nathan Lynch wrote:
> Hi Tom,
>
> Thomas Falcon <tlfalcon@linux.ibm.com> writes:
>> After a migration, it is necessary to send a gratuitous ARP
>> from all running interfaces so that the rest of the network
>> is aware of its new location. However, some supported network
>> devices are unaware that they have been migrated. To avoid network
>> interruptions and other unwanted behavior, force a GARP on all
>> valid, running interfaces as part of the post_mobility_fixup
>> routine.
> [...]
>
>> @@ -331,6 +334,8 @@ void post_mobility_fixup(void)
>>   {
>>   	int rc;
>>   	int activate_fw_token;
>> +	struct net_device *netdev;
>> +	struct net *net;
>>   
>>   	activate_fw_token = rtas_token("ibm,activate-firmware");
>>   	if (activate_fw_token == RTAS_UNKNOWN_SERVICE) {
>> @@ -371,6 +376,21 @@ void post_mobility_fixup(void)
>>   	/* Possibly switch to a new RFI flush type */
>>   	pseries_setup_rfi_flush();
>>   
>> +	/* need to force a gratuitous ARP on running interfaces */
>> +	rtnl_lock();
>> +	for_each_net(net) {
>> +		for_each_netdev(net, netdev) {
>> +			if (netif_device_present(netdev) &&
>> +			    netif_running(netdev) &&
>> +			    !(netdev->flags & (IFF_NOARP | IFF_LOOPBACK)))
>> +				call_netdevice_notifiers(NETDEV_NOTIFY_PEERS,
>> +							 netdev);
>> +				call_netdevice_notifiers(NETDEV_RESEND_IGMP,
>> +							 netdev);
>> +		}
>> +	}
>> +	rtnl_unlock();
>> +
> This isn't an outright nak, but this is not nice. It illustrates the
> need to rethink the pseries partition migration code. There is no
> mechanism for drivers and other interested code to prepare for a
> migration or to adjust to the destination. So post_mobility_fixup() will
> continue to grow into a fragile collection of calls into unrelated
> subsystems until there is a better design -- either a pseries-specific
> notification/callback mechanism, or something based on the pm framework.
>
> My understanding is that this is needed specifically for ibmveth and,
> unlike ibmvnic, the platform does not provide any notification to that
> driver that a migration has occurred, right?

Correct, the ibmveth device, unlike ibmvnic, receives no signal or 
notification at all in the event of a partition migration, so it can not 
handle it or send a gratuitous ARP because from the driver's perspective 
nothing has changed.  As you've described, there is no existing notifier 
in the kernel to inform interested parties that the system has migrated 
or is about to migrate. Without adding the needed infrastructure to do 
that, I'm not sure how else to fix this.

Tom

Re: [RFC PATCH] powerpc/pseries/mobility: notify network peers after migration

[Thomas Falcon]

On 11/6/19 4:14 PM, Nathan Lynch wrote:
> Hi Tom,
>
> Thomas Falcon <tlfalcon@linux.ibm.com> writes:
>> After a migration, it is necessary to send a gratuitous ARP
>> from all running interfaces so that the rest of the network
>> is aware of its new location. However, some supported network
>> devices are unaware that they have been migrated. To avoid network
>> interruptions and other unwanted behavior, force a GARP on all
>> valid, running interfaces as part of the post_mobility_fixup
>> routine.
> [...]
>
>> @@ -331,6 +334,8 @@ void post_mobility_fixup(void)
>>   {
>>   	int rc;
>>   	int activate_fw_token;
>> +	struct net_device *netdev;
>> +	struct net *net;
>>   
>>   	activate_fw_token = rtas_token("ibm,activate-firmware");
>>   	if (activate_fw_token == RTAS_UNKNOWN_SERVICE) {
>> @@ -371,6 +376,21 @@ void post_mobility_fixup(void)
>>   	/* Possibly switch to a new RFI flush type */
>>   	pseries_setup_rfi_flush();
>>   
>> +	/* need to force a gratuitous ARP on running interfaces */
>> +	rtnl_lock();
>> +	for_each_net(net) {
>> +		for_each_netdev(net, netdev) {
>> +			if (netif_device_present(netdev) &&
>> +			    netif_running(netdev) &&
>> +			    !(netdev->flags & (IFF_NOARP | IFF_LOOPBACK)))
>> +				call_netdevice_notifiers(NETDEV_NOTIFY_PEERS,
>> +							 netdev);
>> +				call_netdevice_notifiers(NETDEV_RESEND_IGMP,
>> +							 netdev);
>> +		}
>> +	}
>> +	rtnl_unlock();
>> +
> This isn't an outright nak, but this is not nice. It illustrates the
> need to rethink the pseries partition migration code. There is no
> mechanism for drivers and other interested code to prepare for a
> migration or to adjust to the destination. So post_mobility_fixup() will
> continue to grow into a fragile collection of calls into unrelated
> subsystems until there is a better design -- either a pseries-specific
> notification/callback mechanism, or something based on the pm framework.
>
> My understanding is that this is needed specifically for ibmveth and,
> unlike ibmvnic, the platform does not provide any notification to that
> driver that a migration has occurred, right?

Correct, the ibmveth device, unlike ibmvnic, receives no signal or 
notification at all in the event of a partition migration, so it can not 
handle it or send a gratuitous ARP because from the driver's perspective 
nothing has changed.  As you've described, there is no existing notifier 
in the kernel to inform interested parties that the system has migrated 
or is about to migrate. Without adding the needed infrastructure to do 
that, I'm not sure how else to fix this.

Tom

Re: [RFC PATCH] powerpc/pseries/mobility: notify network peers after migration

[kbuild test robot]

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Hi Thomas,

[FYI, it's a private test report for your RFC patch.]
[auto build test ERROR on powerpc/next]
[also build test ERROR on v5.4-rc6 next-20191107]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]

url:    https://github.com/0day-ci/linux/commits/Thomas-Falcon/powerpc-pseries-mobility-notify-network-peers-after-migration/20191108-030800
base:   https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next
config: powerpc-defconfig (attached as .config)
compiler: powerpc64-linux-gcc (GCC) 7.4.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        GCC_VERSION=7.4.0 make.cross ARCH=powerpc 

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   arch/powerpc/platforms/pseries/mobility.c: In function 'post_mobility_fixup':
>> arch/powerpc/platforms/pseries/mobility.c:383:4: error: this 'if' clause does not guard... [-Werror=misleading-indentation]
       if (netif_device_present(netdev) &&
       ^~
   arch/powerpc/platforms/pseries/mobility.c:388:5: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
        call_netdevice_notifiers(NETDEV_RESEND_IGMP,
        ^~~~~~~~~~~~~~~~~~~~~~~~
   cc1: all warnings being treated as errors

vim +/if +383 arch/powerpc/platforms/pseries/mobility.c

   332	
   333	void post_mobility_fixup(void)
   334	{
   335		int rc;
   336		int activate_fw_token;
   337		struct net_device *netdev;
   338		struct net *net;
   339	
   340		activate_fw_token = rtas_token("ibm,activate-firmware");
   341		if (activate_fw_token == RTAS_UNKNOWN_SERVICE) {
   342			printk(KERN_ERR "Could not make post-mobility "
   343			       "activate-fw call.\n");
   344			return;
   345		}
   346	
   347		do {
   348			rc = rtas_call(activate_fw_token, 0, 1, NULL);
   349		} while (rtas_busy_delay(rc));
   350	
   351		if (rc)
   352			printk(KERN_ERR "Post-mobility activate-fw failed: %d\n", rc);
   353	
   354		/*
   355		 * We don't want CPUs to go online/offline while the device
   356		 * tree is being updated.
   357		 */
   358		cpus_read_lock();
   359	
   360		/*
   361		 * It's common for the destination firmware to replace cache
   362		 * nodes.  Release all of the cacheinfo hierarchy's references
   363		 * before updating the device tree.
   364		 */
   365		cacheinfo_teardown();
   366	
   367		rc = pseries_devicetree_update(MIGRATION_SCOPE);
   368		if (rc)
   369			printk(KERN_ERR "Post-mobility device tree update "
   370				"failed: %d\n", rc);
   371	
   372		cacheinfo_rebuild();
   373	
   374		cpus_read_unlock();
   375	
   376		/* Possibly switch to a new RFI flush type */
   377		pseries_setup_rfi_flush();
   378	
   379		/* need to force a gratuitous ARP on running interfaces */
   380		rtnl_lock();
   381		for_each_net(net) {
   382			for_each_netdev(net, netdev) {
 > 383				if (netif_device_present(netdev) &&
   384				    netif_running(netdev) &&
   385				    !(netdev->flags & (IFF_NOARP | IFF_LOOPBACK)))
   386					call_netdevice_notifiers(NETDEV_NOTIFY_PEERS,
   387								 netdev);
   388					call_netdevice_notifiers(NETDEV_RESEND_IGMP,
   389								 netdev);
   390			}
   391		}
   392		rtnl_unlock();
   393	
   394		return;
   395	}
   396	

---
0-DAY kernel test infrastructure                 Open Source Technology Center
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org Intel Corporation

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Re: [RFC PATCH] powerpc/pseries/mobility: notify network peers after migration

[kbuild test robot]

[-- Attachment #1: Type: text/plain, Size: 3851 bytes --]

Hi Thomas,

[FYI, it's a private test report for your RFC patch.]
[auto build test WARNING on powerpc/next]
[cannot apply to v5.4-rc6 next-20191108]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]

url:    https://github.com/0day-ci/linux/commits/Thomas-Falcon/powerpc-pseries-mobility-notify-network-peers-after-migration/20191108-030800
base:   https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next
config: powerpc-allyesconfig (attached as .config)
compiler: powerpc64-linux-gcc (GCC) 7.4.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        GCC_VERSION=7.4.0 make.cross ARCH=powerpc 

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

   arch/powerpc//platforms/pseries/mobility.c: In function 'post_mobility_fixup':
>> arch/powerpc//platforms/pseries/mobility.c:383:4: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
       if (netif_device_present(netdev) &&
       ^~
   arch/powerpc//platforms/pseries/mobility.c:388:5: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
        call_netdevice_notifiers(NETDEV_RESEND_IGMP,
        ^~~~~~~~~~~~~~~~~~~~~~~~

vim +/if +383 arch/powerpc//platforms/pseries/mobility.c

   332	
   333	void post_mobility_fixup(void)
   334	{
   335		int rc;
   336		int activate_fw_token;
   337		struct net_device *netdev;
   338		struct net *net;
   339	
   340		activate_fw_token = rtas_token("ibm,activate-firmware");
   341		if (activate_fw_token == RTAS_UNKNOWN_SERVICE) {
   342			printk(KERN_ERR "Could not make post-mobility "
   343			       "activate-fw call.\n");
   344			return;
   345		}
   346	
   347		do {
   348			rc = rtas_call(activate_fw_token, 0, 1, NULL);
   349		} while (rtas_busy_delay(rc));
   350	
   351		if (rc)
   352			printk(KERN_ERR "Post-mobility activate-fw failed: %d\n", rc);
   353	
   354		/*
   355		 * We don't want CPUs to go online/offline while the device
   356		 * tree is being updated.
   357		 */
   358		cpus_read_lock();
   359	
   360		/*
   361		 * It's common for the destination firmware to replace cache
   362		 * nodes.  Release all of the cacheinfo hierarchy's references
   363		 * before updating the device tree.
   364		 */
   365		cacheinfo_teardown();
   366	
   367		rc = pseries_devicetree_update(MIGRATION_SCOPE);
   368		if (rc)
   369			printk(KERN_ERR "Post-mobility device tree update "
   370				"failed: %d\n", rc);
   371	
   372		cacheinfo_rebuild();
   373	
   374		cpus_read_unlock();
   375	
   376		/* Possibly switch to a new RFI flush type */
   377		pseries_setup_rfi_flush();
   378	
   379		/* need to force a gratuitous ARP on running interfaces */
   380		rtnl_lock();
   381		for_each_net(net) {
   382			for_each_netdev(net, netdev) {
 > 383				if (netif_device_present(netdev) &&
   384				    netif_running(netdev) &&
   385				    !(netdev->flags & (IFF_NOARP | IFF_LOOPBACK)))
   386					call_netdevice_notifiers(NETDEV_NOTIFY_PEERS,
   387								 netdev);
   388					call_netdevice_notifiers(NETDEV_RESEND_IGMP,
   389								 netdev);
   390			}
   391		}
   392		rtnl_unlock();
   393	
   394		return;
   395	}
   396	

---
0-DAY kernel test infrastructure                 Open Source Technology Center
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org Intel Corporation

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