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Date: Thu, 19 Dec 2013 11:17:39 +0800
From: Fan Du <fan.du@...driver.com>
To: Eric Dumazet <eric.dumazet@...il.com>
CC: 王聪 <xiyou.wangcong@...il.com>,
<steffen.klassert@...unet.com>, <davem@...emloft.net>,
<netdev@...r.kernel.org>
Subject: [PATCHv3 net-next] xfrm: Namespacify xfrm_policy_sk_bundles
On 2013年12月19日 10:15, Eric Dumazet wrote:
>> I think an analogy of llist_add_batch for the updating part will be ok for this:
>> >
>> > struct dst_entry *first;
>> > do {
>> > xdst->u.dst.next = first = ACCESS_ONCE(xfrm_policy_sk_bundles);
>> > } while (cmpxchg(&xfrm_policy_sk_bundles, first,&xdst->u.dst) != first);
>> >
>> >
>> > And the deleting part:
>> >
>> > head = xchg(&net->xfrm.xfrm_policy_sk_bundles, NULL);
>> >
>> >
> The point is to_use_ the helpers, so that code review is easy.
>
> llist.h is safe, it was extensively discussed and adopted.
>
> If you want to get rid of the spinlock, then use llist_del_all() for the
> deleting, and llist_add() for the addition.
>
> Really, its that simple.
Ok, I will use common api suggested by you, then locks is gone at the cost
of xfrm_dst growing up a bit, sizeof(struct llist_node).
From b4c5fc86861abd98866111a7b1b51dc13d546a0c Mon Sep 17 00:00:00 2001
From: Fan Du <fan.du@...driver.com>
Date: Thu, 19 Dec 2013 11:03:20 +0800
Subject: [PATCHv3 net-next] xfrm: Namespacify xfrm_policy_sk_bundles
xfrm_policy_sk_bundles, protected by net->xfrm.xfrm_policy_sk_bundle_lock
should be put into netns xfrm structure, otherwise xfrm_policy_sk_bundles
can be corrupted from different net namespace.
Moreover current xfrm_policy_sk_bundle_lock used in below two scenarios:
1. xfrm_lookup(Process context) vs __xfrm_garbage_collect(softirq context)
2. xfrm_lookup(Process context) vs __xfrm_garbage_collect(Process context
when SPD change or dev down)
We can use lock less list to cater to those two scenarios as suggested by
Eric Dumazet.
Signed-off-by: Fan Du <fan.du@...driver.com>
Assisted-by: Eric Dumazet <edumazet@...gle.com>
---
v2:
Fix incorrect commit log.
v3:
Drop xchg, use llist instead, adviced by Eric Dumazet.
Build test only.
---
include/net/netns/xfrm.h | 2 +-
include/net/xfrm.h | 1 +
net/xfrm/xfrm_policy.c | 26 ++++++--------------------
3 files changed, 8 insertions(+), 21 deletions(-)
diff --git a/include/net/netns/xfrm.h b/include/net/netns/xfrm.h
index 1006a26..22f4f90 100644
--- a/include/net/netns/xfrm.h
+++ b/include/net/netns/xfrm.h
@@ -58,9 +58,9 @@ struct netns_xfrm {
struct dst_ops xfrm6_dst_ops;
#endif
spinlock_t xfrm_state_lock;
- spinlock_t xfrm_policy_sk_bundle_lock;
rwlock_t xfrm_policy_lock;
struct mutex xfrm_cfg_mutex;
+ struct llist_head xp_sk_bundles_list;
};
#endif
diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index 59f5d0a..05296ab 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -957,6 +957,7 @@ struct xfrm_dst {
u32 child_mtu_cached;
u32 route_cookie;
u32 path_cookie;
+ struct llist_node xdst_llist;
};
#ifdef CONFIG_XFRM
diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index a7487f3..fb286af 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -39,8 +39,6 @@
#define XFRM_QUEUE_TMO_MAX ((unsigned)(60*HZ))
#define XFRM_MAX_QUEUE_LEN 100
-static struct dst_entry *xfrm_policy_sk_bundles;
-
static DEFINE_SPINLOCK(xfrm_policy_afinfo_lock);
static struct xfrm_policy_afinfo __rcu *xfrm_policy_afinfo[NPROTO]
__read_mostly;
@@ -2108,12 +2106,7 @@ struct dst_entry *xfrm_lookup(struct net *net, struct dst_entry *dst_orig,
}
dst_hold(&xdst->u.dst);
-
- spin_lock_bh(&net->xfrm.xfrm_policy_sk_bundle_lock);
- xdst->u.dst.next = xfrm_policy_sk_bundles;
- xfrm_policy_sk_bundles = &xdst->u.dst;
- spin_unlock_bh(&net->xfrm.xfrm_policy_sk_bundle_lock);
-
+ llist_add(&xdst->xdst_llist, &net->xfrm.xp_sk_bundles_list);
route = xdst->route;
}
}
@@ -2549,18 +2542,12 @@ static struct dst_entry *xfrm_negative_advice(struct dst_entry *dst)
static void __xfrm_garbage_collect(struct net *net)
{
- struct dst_entry *head, *next;
-
- spin_lock_bh(&net->xfrm.xfrm_policy_sk_bundle_lock);
- head = xfrm_policy_sk_bundles;
- xfrm_policy_sk_bundles = NULL;
- spin_unlock_bh(&net->xfrm.xfrm_policy_sk_bundle_lock);
+ struct llist_node *head;
+ struct xfrm_dst *xdst;
- while (head) {
- next = head->next;
- dst_free(head);
- head = next;
- }
+ head = llist_del_all(&net->xfrm.xp_sk_bundles_list);
+ llist_for_each_entry(xdst, head, xdst_llist)
+ dst_free(&xdst->u.dst);
}
void xfrm_garbage_collect(struct net *net)
@@ -2942,7 +2929,6 @@ static int __net_init xfrm_net_init(struct net *net)
/* Initialize the per-net locks here */
spin_lock_init(&net->xfrm.xfrm_state_lock);
rwlock_init(&net->xfrm.xfrm_policy_lock);
- spin_lock_init(&net->xfrm.xfrm_policy_sk_bundle_lock);
mutex_init(&net->xfrm.xfrm_cfg_mutex);
return 0;
--
1.7.9.5
--
浮沉随浪只记今朝笑
--fan
--
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