* [PATCH net-next v2] ip_tunnel: Add dst_cache management lwtunnel_state of ip tunnel
@ 2019-02-22 3:00 wenxu
2019-02-22 3:39 ` David Ahern
0 siblings, 1 reply; 6+ messages in thread
From: wenxu @ 2019-02-22 3:00 UTC (permalink / raw)
To: davem, netdev
From: wenxu <wenxu@ucloud.cn>
The lwtunnel_state is not init the dst_cache Which make the
ip_md_tunnel_xmit can't use the dst_cache. It will lookup
route table every packets.
Signed-off-by: wenxu <wenxu@ucloud.cn>
---
net/ipv4/ip_tunnel_core.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/net/ipv4/ip_tunnel_core.c b/net/ipv4/ip_tunnel_core.c
index 9a0e67b..f91ef7a 100644
--- a/net/ipv4/ip_tunnel_core.c
+++ b/net/ipv4/ip_tunnel_core.c
@@ -252,6 +252,12 @@ static int ip_tun_build_state(struct nlattr *attr,
tun_info = lwt_tun_info(new_state);
+ err = dst_cache_init(&tun_info->dst_cache, GFP_ATOMIC);
+ if (err) {
+ lwtstate_free(new_state);
+ return err;
+ }
+
if (tb[LWTUNNEL_IP_ID])
tun_info->key.tun_id = nla_get_be64(tb[LWTUNNEL_IP_ID]);
@@ -278,6 +284,13 @@ static int ip_tun_build_state(struct nlattr *attr,
return 0;
}
+static void ip_tun_destroy_state(struct lwtunnel_state *lwtstate)
+{
+ struct ip_tunnel_info *tun_info = lwt_tun_info(lwtstate);
+
+ dst_cache_destroy(&tun_info->dst_cache);
+}
+
static int ip_tun_fill_encap_info(struct sk_buff *skb,
struct lwtunnel_state *lwtstate)
{
@@ -313,6 +326,7 @@ static int ip_tun_cmp_encap(struct lwtunnel_state *a, struct lwtunnel_state *b)
static const struct lwtunnel_encap_ops ip_tun_lwt_ops = {
.build_state = ip_tun_build_state,
+ .destroy_state = ip_tun_destroy_state,
.fill_encap = ip_tun_fill_encap_info,
.get_encap_size = ip_tun_encap_nlsize,
.cmp_encap = ip_tun_cmp_encap,
--
1.8.3.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH net-next v2] ip_tunnel: Add dst_cache management lwtunnel_state of ip tunnel
2019-02-22 3:00 [PATCH net-next v2] ip_tunnel: Add dst_cache management lwtunnel_state of ip tunnel wenxu
@ 2019-02-22 3:39 ` David Ahern
2019-02-22 4:14 ` wenxu
0 siblings, 1 reply; 6+ messages in thread
From: David Ahern @ 2019-02-22 3:39 UTC (permalink / raw)
To: wenxu, davem, netdev
On 2/21/19 10:00 PM, wenxu@ucloud.cn wrote:
> From: wenxu <wenxu@ucloud.cn>
>
> The lwtunnel_state is not init the dst_cache Which make the
> ip_md_tunnel_xmit can't use the dst_cache. It will lookup
> route table every packets.
>
> Signed-off-by: wenxu <wenxu@ucloud.cn>
> ---
> net/ipv4/ip_tunnel_core.c | 14 ++++++++++++++
> 1 file changed, 14 insertions(+)
>
> diff --git a/net/ipv4/ip_tunnel_core.c b/net/ipv4/ip_tunnel_core.c
> index 9a0e67b..f91ef7a 100644
> --- a/net/ipv4/ip_tunnel_core.c
> +++ b/net/ipv4/ip_tunnel_core.c
> @@ -252,6 +252,12 @@ static int ip_tun_build_state(struct nlattr *attr,
>
> tun_info = lwt_tun_info(new_state);
>
> + err = dst_cache_init(&tun_info->dst_cache, GFP_ATOMIC);
build_state is called with rtnl held. Unless I am missing something, you
don't need ATOMIC here.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH net-next v2] ip_tunnel: Add dst_cache management lwtunnel_state of ip tunnel
2019-02-22 3:39 ` David Ahern
@ 2019-02-22 4:14 ` wenxu
2019-02-22 15:03 ` David Ahern
0 siblings, 1 reply; 6+ messages in thread
From: wenxu @ 2019-02-22 4:14 UTC (permalink / raw)
To: David Ahern, davem, netdev
On 2/22/2019 11:39 AM, David Ahern wrote:
> On 2/21/19 10:00 PM, wenxu@ucloud.cn wrote:
>> From: wenxu <wenxu@ucloud.cn>
>>
>> The lwtunnel_state is not init the dst_cache Which make the
>> ip_md_tunnel_xmit can't use the dst_cache. It will lookup
>> route table every packets.
>>
>> Signed-off-by: wenxu <wenxu@ucloud.cn>
>> ---
>> net/ipv4/ip_tunnel_core.c | 14 ++++++++++++++
>> 1 file changed, 14 insertions(+)
>>
>> diff --git a/net/ipv4/ip_tunnel_core.c b/net/ipv4/ip_tunnel_core.c
>> index 9a0e67b..f91ef7a 100644
>> --- a/net/ipv4/ip_tunnel_core.c
>> +++ b/net/ipv4/ip_tunnel_core.c
>> @@ -252,6 +252,12 @@ static int ip_tun_build_state(struct nlattr *attr,
>>
>> tun_info = lwt_tun_info(new_state);
>>
>> + err = dst_cache_init(&tun_info->dst_cache, GFP_ATOMIC);
> build_state is called with rtnl held. Unless I am missing something, you
> don't need ATOMIC here.
If set GFP_KERNEL shows following:
Feb 22 07:07:03 A1_V5_02 kernel: BUG: sleeping function called from invalid context at kernel/locking/mutex.c:1301
Feb 22 07:07:03 A1_V5_02 kernel: in_atomic(): 1, irqs_disabled(): 0, pid: 7950, name: ip
Feb 22 07:07:03 A1_V5_02 kernel: CPU: 21 PID: 7950 Comm: ip Kdump: loaded Not tainted 5.0.0-rc6-next-20190215 #14
Feb 22 07:07:03 A1_V5_02 kernel: Hardware name: Inspur SA5112M5/YZMB-00870-101, BIOS 4.0.3 05/22/2018
Feb 22 07:07:03 A1_V5_02 kernel: Call Trace:
Feb 22 07:07:03 A1_V5_02 kernel: dump_stack+0x5a/0x73
Feb 22 07:07:03 A1_V5_02 kernel: ___might_sleep+0xfc/0x120
Feb 22 07:07:03 A1_V5_02 kernel: mutex_lock_killable+0x1c/0x42
Feb 22 07:07:03 A1_V5_02 kernel: pcpu_alloc+0x390/0x6f0
Feb 22 07:07:03 A1_V5_02 kernel: ? __nla_parse+0xf8/0x160
Feb 22 07:07:03 A1_V5_02 kernel: dst_cache_init+0x1d/0x40
Feb 22 07:07:03 A1_V5_02 kernel: ip_tun_build_state+0x75/0x140
Feb 22 07:07:03 A1_V5_02 kernel: lwtunnel_build_state+0x92/0xf0
Feb 22 07:07:03 A1_V5_02 kernel: fib_create_info+0x74e/0x1020
build_state in the rcu_read_lock and disable the preempt
rcu_read_lock();
ops = rcu_dereference(lwtun_encaps[encap_type]);
if (likely(ops && ops->build_state && try_module_get(ops->owner))) {
found = true;
ret = ops->build_state(encap, family, cfg, lws, extack);
if (ret)
module_put(ops->owner);
}
rcu_read_unlock();
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH net-next v2] ip_tunnel: Add dst_cache management lwtunnel_state of ip tunnel
2019-02-22 4:14 ` wenxu
@ 2019-02-22 15:03 ` David Ahern
2019-02-22 15:21 ` wenxu
0 siblings, 1 reply; 6+ messages in thread
From: David Ahern @ 2019-02-22 15:03 UTC (permalink / raw)
To: wenxu, davem, netdev
On 2/21/19 11:14 PM, wenxu wrote:
> build_state in the rcu_read_lock and disable the preempt
>
> rcu_read_lock();
> ops = rcu_dereference(lwtun_encaps[encap_type]);
> if (likely(ops && ops->build_state && try_module_get(ops->owner))) {
> found = true;
> ret = ops->build_state(encap, family, cfg, lws, extack);
> if (ret)
> module_put(ops->owner);
> }
> rcu_read_unlock();
>
Missed that.
Once a reference is taken the rcu_read_lock can be dropped before
calling build_state allowing the allocations to be GFP_KERNEL.
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH net-next v2] ip_tunnel: Add dst_cache management lwtunnel_state of ip tunnel
2019-02-22 15:03 ` David Ahern
@ 2019-02-22 15:21 ` wenxu
2019-02-22 22:16 ` David Ahern
0 siblings, 1 reply; 6+ messages in thread
From: wenxu @ 2019-02-22 15:21 UTC (permalink / raw)
To: David Ahern, davem, netdev
On 2019/2/22 下午11:03, David Ahern wrote:
> On 2/21/19 11:14 PM, wenxu wrote:
>> build_state in the rcu_read_lock and disable the preempt
>>
>> rcu_read_lock();
>> ops = rcu_dereference(lwtun_encaps[encap_type]);
>> if (likely(ops && ops->build_state && try_module_get(ops->owner))) {
>> found = true;
>> ret = ops->build_state(encap, family, cfg, lws, extack);
>> if (ret)
>> module_put(ops->owner);
>> }
>> rcu_read_unlock();
>>
> Missed that.
>
> Once a reference is taken the rcu_read_lock can be dropped before
> calling build_state allowing the allocations to be GFP_KERNEL.
>
I don't think the rcu_read_lock can be dropped. The whole operation of the reference should be protect
in the rcu_read_lock that ensure the ops will not be destroy (if it will be)
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH net-next v2] ip_tunnel: Add dst_cache management lwtunnel_state of ip tunnel
2019-02-22 15:21 ` wenxu
@ 2019-02-22 22:16 ` David Ahern
0 siblings, 0 replies; 6+ messages in thread
From: David Ahern @ 2019-02-22 22:16 UTC (permalink / raw)
To: wenxu, davem, netdev
On 2/22/19 10:21 AM, wenxu wrote:
> On 2019/2/22 下午11:03, David Ahern wrote:
>> On 2/21/19 11:14 PM, wenxu wrote:
>>> build_state in the rcu_read_lock and disable the preempt
>>>
>>> rcu_read_lock();
>>> ops = rcu_dereference(lwtun_encaps[encap_type]);
>>> if (likely(ops && ops->build_state && try_module_get(ops->owner))) {
>>> found = true;
>>> ret = ops->build_state(encap, family, cfg, lws, extack);
>>> if (ret)
>>> module_put(ops->owner);
>>> }
>>> rcu_read_unlock();
>>>
>> Missed that.
>>
>> Once a reference is taken the rcu_read_lock can be dropped before
>> calling build_state allowing the allocations to be GFP_KERNEL.
>>
> I don't think the rcu_read_lock can be dropped. The whole operation of the reference should be protect
>
> in the rcu_read_lock that ensure the ops will not be destroy (if it will be)
>
If 'try_module_get(ops->owner)' succeeds then a reference is held so the
ops will not go away.
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2019-02-22 22:16 UTC | newest]
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2019-02-22 3:00 [PATCH net-next v2] ip_tunnel: Add dst_cache management lwtunnel_state of ip tunnel wenxu
2019-02-22 3:39 ` David Ahern
2019-02-22 4:14 ` wenxu
2019-02-22 15:03 ` David Ahern
2019-02-22 15:21 ` wenxu
2019-02-22 22:16 ` David Ahern
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