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| author |   Eric Dumazet <eric.dumazet@gmail.com> | 2010-06-14 16:15:23 +0200 |
|---|---|---|
| committer |   Patrick McHardy <kaber@trash.net> | 2010-06-14 16:15:23 +0200 |
| commit | f5c5440d40a24c5dc8030cde0a03debe87de4afb (patch) | |
| tree | 2dacda8f2134860488dad9783dbcc7ef970f2985 | |
| parent | netfilter: nfnetlink_log: RCU conversion (diff) | |
| download | linux-dev-f5c5440d40a24c5dc8030cde0a03debe87de4afb.tar.xz linux-dev-f5c5440d40a24c5dc8030cde0a03debe87de4afb.zip | |
netfilter: nfnetlink_log: RCU conversion, part 2
- must use atomic_inc_not_zero() in instance_lookup_get()
- must use hlist_add_head_rcu() instead of hlist_add_head()
- must use hlist_del_rcu() instead of hlist_del()
- Introduce NFULNL_COPY_DISABLED to stop lockless reader from using an
instance, before we do final instance_put() on it.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
| -rw-r--r-- | include/linux/netfilter/nfnetlink_log.h | 1 | ||||
| -rw-r--r-- | net/netfilter/nfnetlink_log.c | 18 |
2 files changed, 13 insertions, 6 deletions
diff --git a/include/linux/netfilter/nfnetlink_log.h b/include/linux/netfilter/nfnetlink_log.h index d3bab7a2c9b7..1d0b84aa1d42 100644 --- a/include/linux/netfilter/nfnetlink_log.h +++ b/include/linux/netfilter/nfnetlink_log.h @@ -89,6 +89,7 @@ enum nfulnl_attr_config { #define NFULNL_COPY_NONE 0x00 #define NFULNL_COPY_META 0x01 #define NFULNL_COPY_PACKET 0x02 +#define NFULNL_COPY_DISABLED 0x03 #define NFULNL_CFG_F_SEQ 0x0001 #define NFULNL_CFG_F_SEQ_GLOBAL 0x0002 diff --git a/net/netfilter/nfnetlink_log.c b/net/netfilter/nfnetlink_log.c index 8ec23ec568e7..fb86a51bb65a 100644 --- a/net/netfilter/nfnetlink_log.c +++ b/net/netfilter/nfnetlink_log.c @@ -109,8 +109,8 @@ instance_lookup_get(u_int16_t group_num) rcu_read_lock_bh(); inst = __instance_lookup(group_num); - if (inst) - instance_get(inst); + if (inst && !atomic_inc_not_zero(&inst->use)) + inst = NULL; rcu_read_unlock_bh(); return inst; @@ -171,7 +171,7 @@ instance_create(u_int16_t group_num, int pid) inst->copy_mode = NFULNL_COPY_PACKET; inst->copy_range = NFULNL_COPY_RANGE_MAX; - hlist_add_head(&inst->hlist, + hlist_add_head_rcu(&inst->hlist, &instance_table[instance_hashfn(group_num)]); spin_unlock_bh(&instances_lock); @@ -185,18 +185,23 @@ out_unlock: static void __nfulnl_flush(struct nfulnl_instance *inst); +/* called with BH disabled */ static void __instance_destroy(struct nfulnl_instance *inst) { /* first pull it out of the global list */ - hlist_del(&inst->hlist); + hlist_del_rcu(&inst->hlist); /* then flush all pending packets from skb */ - spin_lock_bh(&inst->lock); + spin_lock(&inst->lock); + + /* lockless readers wont be able to use us */ + inst->copy_mode = NFULNL_COPY_DISABLED; + if (inst->skb) __nfulnl_flush(inst); - spin_unlock_bh(&inst->lock); + spin_unlock(&inst->lock); /* and finally put the refcount */ instance_put(inst); @@ -624,6 +629,7 @@ nfulnl_log_packet(u_int8_t pf, size += nla_total_size(data_len); break; + case NFULNL_COPY_DISABLED: default: goto unlock_and_release; } |