linux-stable.git/include/net/udplite.h, branch linux-3.1.y

udplite: fast-path computation of checksum coverage

2011-10-17T23:07:30+00:00

Commit 903ab86d195cca295379699299c5fc10beba31c7 of 1 March this year ("udp: Add
lockless transmit path") introduced a new fast TX path that broke the checksum
coverage computation of UDP-lite, which so far depended on up->len (only set
if the socket is locked and 0 in the fast path).

Fixed by providing both fast- and slow-path computation of checksum coverage.
The latter can be removed when UDP(-lite)v6 also uses a lockless transmit path.
 
Reported-by: Thomas Volkert 
Signed-off-by: Gerrit Renker 
Signed-off-by: David S. Miller

udp: Switch to ip_finish_skb

2011-03-01T20:35:03+00:00

This patch converts UDP to use the new ip_finish_skb API.  This
would then allows us to more easily use ip_make_skb which allows
UDP to run without a socket lock.

Signed-off-by: Herbert Xu 
Acked-by: Eric Dumazet 
Signed-off-by: David S. Miller

udp: introduce struct udp_table and multiple spinlocks

2008-10-29T08:41:45+00:00

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

[UDP]: Restore missing inDatagrams increments

2008-01-28T22:56:33+00:00

The previous move of the the UDP inDatagrams counter caused the
counting of encapsulated packets, SUNRPC data (as opposed to call)
packets and RXRPC packets to go missing.

This patch restores all of these.

Signed-off-by: Herbert Xu 
Signed-off-by: David S. Miller

[UDP]: Revert 2-pass hashing changes.

2007-06-07T20:40:50+00:00

This reverts changesets:

6aaf47fa48d3c44280810b1b470261d340e4ed87
b7b5f487ab39bc10ed0694af35651a03d9cb97ff
de34ed91c4ffa4727964a832c46e624dd1495cf5
fc038410b4b1643766f8033f4940bcdb1dace633

There are still some correctness issues recently
discovered which do not have a known fix that doesn't
involve doing a full hash table scan on port bind.

So revert for now.

Signed-off-by: David S. Miller

[UDP]: Fix AF-specific references in AF-agnostic code.

2007-05-11T06:47:22+00:00

__udp_lib_port_inuse() cannot make direct references to
inet_sk(sk)->rcv_saddr as that is ipv4 specific state and
this code is used by ipv6 too.

Use an operations vector to solve this, and this also paves
the way for ipv6 support for non-wild saddr hashing in UDP.

Signed-off-by: David S. Miller

[SK_BUFF]: Introduce udp_hdr(), remove skb->h.uh

2007-04-26T05:25:22+00:00

Signed-off-by: Arnaldo Carvalho de Melo 
Signed-off-by: David S. Miller

[SK_BUFF]: Introduce skb_transport_offset()

2007-04-26T05:25:16+00:00

For the quite common 'skb->h.raw - skb->data' sequence.

Signed-off-by: Arnaldo Carvalho de Melo 
Signed-off-by: David S. Miller

[UDP]: Clean up UDP-Lite receive checksum

2007-04-26T05:23:51+00:00

This patch eliminates some duplicate code for the verification of
receive checksums between UDP-Lite and UDP.  It does this by
introducing __skb_checksum_complete_head which is identical to
__skb_checksum_complete_head apart from the fact that it takes
a length parameter rather than computing the first skb->len bytes.

As a result UDP-Lite will be able to use hardware checksum offload
for packets which do not use partial coverage checksums.  It also
means that UDP-Lite loopback no longer does unnecessary checksum
verification.

If any NICs start support UDP-Lite this would also start working
automatically.

This patch removes the assumption that msg_flags has MSG_TRUNC clear
upon entry in recvmsg.

Signed-off-by: Herbert Xu 
Signed-off-by: David S. Miller

[NET]: Fix assorted misannotations (from md5 and udplite merges).

2006-12-03T05:27:16+00:00

Signed-off-by: Al Viro 
Signed-off-by: David S. Miller