* [PATCH] net: Updates to netif_index_is_vrf
@ 2015-08-16 0:09 David Ahern
2015-08-16 0:39 ` Florian Westphal
0 siblings, 1 reply; 3+ messages in thread
From: David Ahern @ 2015-08-16 0:09 UTC (permalink / raw)
To: netdev; +Cc: eric.dumazet, David Ahern
As Eric noted netif_index_is_vrf is not called with rcu_read_lock held,
so use dev_get_by_index instead of dev_get_by_index_rcu.
If VRF is not enabled or oif is 0 skip the device lookup.
Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
---
include/linux/netdevice.h | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index f7a6ef2fae3a..dca36a618781 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -3819,12 +3819,20 @@ static inline bool netif_is_vrf(const struct net_device *dev)
static inline bool netif_index_is_vrf(struct net *net, int ifindex)
{
- struct net_device *dev = dev_get_by_index_rcu(net, ifindex);
bool rc = false;
- if (dev)
- rc = netif_is_vrf(dev);
+#if IS_ENABLED(CONFIG_NET_VRF)
+ struct net_device *dev;
+
+ if (ifindex == 0)
+ return false;
+ dev = dev_get_by_index(net, ifindex);
+ if (dev) {
+ rc = netif_is_vrf(dev);
+ dev_put(dev);
+ }
+#endif
return rc;
}
--
2.3.2 (Apple Git-55)
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH] net: Updates to netif_index_is_vrf
2015-08-16 0:09 [PATCH] net: Updates to netif_index_is_vrf David Ahern
@ 2015-08-16 0:39 ` Florian Westphal
2015-08-16 13:34 ` David Ahern
0 siblings, 1 reply; 3+ messages in thread
From: Florian Westphal @ 2015-08-16 0:39 UTC (permalink / raw)
To: David Ahern; +Cc: netdev, eric.dumazet
David Ahern <dsa@cumulusnetworks.com> wrote:
> As Eric noted netif_index_is_vrf is not called with rcu_read_lock held,
> so use dev_get_by_index instead of dev_get_by_index_rcu.
>
> If VRF is not enabled or oif is 0 skip the device lookup.
>
> Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Why not
> static inline bool netif_index_is_vrf(struct net *net, int ifindex)
> {
> - struct net_device *dev = dev_get_by_index_rcu(net, ifindex);
> bool rc = false;
>
> - if (dev)
> - rc = netif_is_vrf(dev);
> +#if IS_ENABLED(CONFIG_NET_VRF)
> + struct net_device *dev;
> +
> + if (ifindex == 0)
> + return false;
rcu_read_lock();
dev = dev_get_by_index_rcu(net, ifindex);
if (dev)
rc = netif_is_vrf(dev);
rcu_read_unlock();
> +#endif
> return rc;
instead?
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] net: Updates to netif_index_is_vrf
2015-08-16 0:39 ` Florian Westphal
@ 2015-08-16 13:34 ` David Ahern
0 siblings, 0 replies; 3+ messages in thread
From: David Ahern @ 2015-08-16 13:34 UTC (permalink / raw)
To: Florian Westphal; +Cc: netdev, eric.dumazet
On 8/15/15 6:39 PM, Florian Westphal wrote:
> David Ahern <dsa@cumulusnetworks.com> wrote:
>> As Eric noted netif_index_is_vrf is not called with rcu_read_lock held,
>> so use dev_get_by_index instead of dev_get_by_index_rcu.
>>
>> If VRF is not enabled or oif is 0 skip the device lookup.
>>
>> Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
>
> Why not
>
>> static inline bool netif_index_is_vrf(struct net *net, int ifindex)
>> {
>> - struct net_device *dev = dev_get_by_index_rcu(net, ifindex);
>> bool rc = false;
>>
>> - if (dev)
>> - rc = netif_is_vrf(dev);
>> +#if IS_ENABLED(CONFIG_NET_VRF)
>> + struct net_device *dev;
>> +
>> + if (ifindex == 0)
>> + return false;
>
> rcu_read_lock();
>
> dev = dev_get_by_index_rcu(net, ifindex);
> if (dev)
> rc = netif_is_vrf(dev);
>
> rcu_read_unlock();
>
>> +#endif
>> return rc;
>
> instead?
sure. That saves the inc and dec on the refcnt. will respin.
David
^ permalink raw reply [flat|nested] 3+ messages in thread
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2015-08-16 0:09 [PATCH] net: Updates to netif_index_is_vrf David Ahern
2015-08-16 0:39 ` Florian Westphal
2015-08-16 13:34 ` David Ahern
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