kernel.git/net/ipv4/udplite.c, branch linux-2.6.37.y

net: fix nulls list corruptions in sk_prot_alloc

2010-12-16T22:26:56Z

Special care is taken inside sk_port_alloc to avoid overwriting skc_node/skc_nulls_node. We should also avoid overwriting skc_bind_node/skc_portaddr_node. The patch fixes the following crash: BUG: unable to handle kernel paging request at fffffffffffffff0 IP: [] udp4_lib_lookup2+0xad/0x370 [] __udp4_lib_lookup+0x282/0x360 [] __udp4_lib_rcv+0x31e/0x700 [] ? ip_local_deliver_finish+0x65/0x190 [] ? ip_local_deliver+0x88/0xa0 [] udp_rcv+0x15/0x20 [] ip_local_deliver_finish+0x65/0x190 [] ip_local_deliver+0x88/0xa0 [] ip_rcv_finish+0x32d/0x6f0 [] ? netif_receive_skb+0x99c/0x11c0 [] ip_rcv+0x2bb/0x350 [] netif_receive_skb+0x99c/0x11c0 Signed-off-by: Leonard Crestez Signed-off-by: Octavian Purdila Acked-by: Eric Dumazet Signed-off-by: David S. Miller

net/ipv4: EXPORT_SYMBOL cleanups

2010-07-12T19:57:54Z

CodingStyle cleanups EXPORT_SYMBOL should immediately follow the symbol declaration. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

net: spread __net_init, __net_exit

2010-01-18T03:16:02Z

__net_init/__net_exit are apparently not going away, so use them to full extent. In some cases __net_init was removed, because it was called from __net_exit code. Signed-off-by: Alexey Dobriyan Signed-off-by: David S. Miller

net: drop capability from protocol definitions

2009-11-06T05:40:17Z

struct can_proto had a capability field which wasn't ever used. It is dropped entirely. struct inet_protosw had a capability field which can be more clearly expressed in the code by just checking if sock->type = SOCK_RAW. Signed-off-by: Eric Paris Acked-by: Arnaldo Carvalho de Melo Signed-off-by: David S. Miller

udp: dynamically size hash tables at boot time

2009-10-08T05:00:22Z

UDP_HTABLE_SIZE was initialy defined to 128, which is a bit small for several setups. 4000 active UDP sockets -> 32 sockets per chain in average. An incoming frame has to lookup all sockets to find best match, so long chains hurt latency. Instead of a fixed size hash table that cant be perfect for every needs, let UDP stack choose its table size at boot time like tcp/ip route, using alloc_large_system_hash() helper Add an optional boot parameter, uhash_entries=x so that an admin can force a size between 256 and 65536 if needed, like thash_entries and rhash_entries. dmesg logs two new lines : [ 0.647039] UDP hash table entries: 512 (order: 0, 4096 bytes) [ 0.647099] UDP Lite hash table entries: 512 (order: 0, 4096 bytes) Maximal size on 64bit arches would be 65536 slots, ie 1 MBytes for non debugging spinlocks. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

net: constify struct net_protocol

2009-09-15T00:03:01Z

Remove long removed "inet_protocol_base" declaration. Signed-off-by: Alexey Dobriyan Signed-off-by: David S. Miller

udp: RCU handling for Unicast packets.

2008-10-29T09:11:14Z

Goals are : 1) Optimizing handling of incoming Unicast UDP frames, so that no memory writes should happen in the fast path. Note: Multicasts and broadcasts still will need to take a lock, because doing a full lockless lookup in this case is difficult. 2) No expensive operations in the socket bind/unhash phases : - No expensive synchronize_rcu() calls. - No added rcu_head in socket structure, increasing memory needs, but more important, forcing us to use call_rcu() calls, that have the bad property of making sockets structure cold. (rcu grace period between socket freeing and its potential reuse make this socket being cold in CPU cache). David did a previous patch using call_rcu() and noticed a 20% impact on TCP connection rates. Quoting Cristopher Lameter : "Right. That results in cacheline cooldown. You'd want to recycle the object as they are cache hot on a per cpu basis. That is screwed up by the delayed regular rcu processing. We have seen multiple regressions due to cacheline cooldown. The only choice in cacheline hot sensitive areas is to deal with the complexity that comes with SLAB_DESTROY_BY_RCU or give up on RCU." - Because udp sockets are allocated from dedicated kmem_cache, use of SLAB_DESTROY_BY_RCU can help here. Theory of operation : --------------------- As the lookup is lockfree (using rcu_read_lock()/rcu_read_unlock()), special attention must be taken by readers and writers. Use of SLAB_DESTROY_BY_RCU is tricky too, because a socket can be freed, reused, inserted in a different chain or in worst case in the same chain while readers could do lookups in the same time. In order to avoid loops, a reader must check each socket found in a chain really belongs to the chain the reader was traversing. If it finds a mismatch, lookup must start again at the begining. This *restart* loop is the reason we had to use rdlock for the multicast case, because we dont want to send same message several times to the same socket. We use RCU only for fast path. Thus, /proc/net/udp still takes spinlocks. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

udp: introduce struct udp_table and multiple spinlocks

2008-10-29T08:41:45Z

UDP sockets are hashed in a 128 slots hash table. This hash table is protected by *one* rwlock. This rwlock is readlocked each time an incoming UDP message is handled. This rwlock is writelocked each time a socket must be inserted in hash table (bind time), or deleted from this table (close time) This is not scalable on SMP machines : 1) Even in read mode, lock() and unlock() are atomic operations and must dirty a contended cache line, shared by all cpus. 2) A writer might be starved if many readers are 'in flight'. This can happen on a machine with some NIC receiving many UDP messages. User process can be delayed a long time at socket creation/dismantle time. This patch prepares RCU migration, by introducing 'struct udp_table and struct udp_hslot', and using one spinlock per chain, to reduce contention on central rwlock. Introducing one spinlock per chain reduces latencies, for port randomization on heavily loaded UDP servers. This also speedup bindings to specific ports. udp_lib_unhash() was uninlined, becoming to big. Some cleanups were done to ease review of following patch (RCUification of UDP Unicast lookups) Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

mib: put udplite statistics on struct net

2008-07-18T11:03:45Z

Signed-off-by: Pavel Emelyanov Signed-off-by: David S. Miller

net: remove CVS keywords

2008-06-12T04:00:38Z

This patch removes CVS keywords that weren't updated for a long time from comments. Signed-off-by: Adrian Bunk Signed-off-by: David S. Miller