linux-stable.git/net/ipv4/tcp_input.c, branch linux-3.5.y

tcp: fix regression in urgent data handling

2012-10-12T20:46:57+00:00

[ Upstream commit 1d57f19539c074105791da6384a8ad674bba8037 ]

Stephan Springl found that commit 1402d366019fed "tcp: introduce
tcp_try_coalesce" introduced a regression for rlogin

It turns out problem comes from TCP urgent data handling and
a change in behavior in input path.

rlogin sends two one-byte packets with URG ptr set, and when next data
frame is coalesced, we lack sk_data_ready() calls to wakeup consumer.

Signed-off-by: Eric Dumazet 
Reported-by: Stephan Springl 
Cc: Alexander Duyck 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

tcp: fix cwnd reduction for non-sack recovery

2012-10-02T17:38:55+00:00

[ Upstream commit 7c4a56fec379ac0d7754e0d4da6a7361f1a4fe64 ]

The cwnd reduction in fast recovery is based on the number of packets
newly delivered per ACK. For non-sack connections every DUPACK
signifies a packet has been delivered, but the sender mistakenly
skips counting them for cwnd reduction.

The fix is to compute newly_acked_sacked after DUPACKs are accounted
in sacked_out for non-sack connections.

Signed-off-by: Yuchung Cheng 
Acked-by: Nandita Dukkipati 
Acked-by: Neal Cardwell 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

tcp: perform DMA to userspace only if there is a task waiting for it

2012-08-09T15:23:14+00:00

[ Upstream commit 59ea33a68a9083ac98515e4861c00e71efdc49a1 ]

Back in 2006, commit 1a2449a87b ("[I/OAT]: TCP recv offload to I/OAT")
added support for receive offloading to IOAT dma engine if available.

The code in tcp_rcv_established() tries to perform early DMA copy if
applicable. It however does so without checking whether the userspace
task is actually expecting the data in the buffer.

This is not a problem under normal circumstances, but there is a corner
case where this doesn't work -- and that's when MSG_TRUNC flag to
recvmsg() is used.

If the IOAT dma engine is not used, the code properly checks whether
there is a valid ucopy.task and the socket is owned by userspace, but
misses the check in the dmaengine case.

This problem can be observed in real trivially -- for example 'tbench' is a
good reproducer, as it makes a heavy use of MSG_TRUNC. On systems utilizing
IOAT, you will soon find tbench waiting indefinitely in sk_wait_data(), as they
have been already early-copied in tcp_rcv_established() using dma engine.

This patch introduces the same check we are performing in the simple
iovec copy case to the IOAT case as well. It fixes the indefinite
recvmsg(MSG_TRUNC) hangs.

Signed-off-by: Jiri Kosina 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

tcp: take care of overlaps in tcp_try_coalesce()

2012-05-24T04:28:21+00:00

Sergio Correia reported following warning :

WARNING: at net/ipv4/tcp.c:1301 tcp_cleanup_rbuf+0x4f/0x110()

WARN(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq),
     "cleanup rbuf bug: copied %X seq %X rcvnxt %X\n",
     tp->copied_seq, TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt);

It appears TCP coalescing, and more specifically commit b081f85c297
(net: implement tcp coalescing in tcp_queue_rcv()) should take care of
possible segment overlaps in receive queue. This was properly done in
the case of out_or_order_queue by the caller.

For example, segment at tail of queue have sequence 1000-2000, and we
add a segment with sequence 1500-2500.
This can happen in case of retransmits.

In this case, just don't do the coalescing.

Reported-by: Sergio Correia 
Signed-off-by: Eric Dumazet 
Tested-by: Sergio Correia 
Signed-off-by: David S. Miller

net: introduce skb_try_coalesce()

2012-05-19T22:34:57+00:00

Move tcp_try_coalesce() protocol independent part to
skb_try_coalesce().

skb_try_coalesce() can be used in IPv4 defrag and IPv6 reassembly,
to build optimized skbs (less sk_buff, and possibly less 'headers')

skb_try_coalesce() is zero copy, unless the copy can fit in destination
header (its a rare case)

kfree_skb_partial() is also moved to net/core/skbuff.c and exported,
because IPv6 will need it in patch (ipv6: use skb coalescing in
reassembly).

Signed-off-by: Eric Dumazet 
Cc: Alexander Duyck 
Signed-off-by: David S. Miller

tcp: bool conversions

2012-05-17T18:59:59+00:00

bool conversions where possible.

__inline__ -> inline

space cleanups

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

net: ipv4 and ipv6: Convert printk(KERN_DEBUG to pr_debug

2012-05-16T05:01:03+00:00

Use the current debugging style and enable dynamic_debug.

Signed-off-by: Joe Perches 
Signed-off-by: David S. Miller

net: Convert net_ratelimit uses to net__ratelimited

2012-05-15T17:45:03+00:00

Standardize the net core ratelimited logging functions.

Coalesce formats, align arguments.
Change a printk then vprintk sequence to use printf extension %pV.

Signed-off-by: Joe Perches 
Signed-off-by: David S. Miller

tcp: Out-line tcp_try_rmem_schedule

2012-05-11T03:24:36+00:00

As proposed by Eric, make the tcp_input.o thinner.

add/remove: 1/1 grow/shrink: 1/4 up/down: 868/-1329 (-461)
function                                     old     new   delta
tcp_try_rmem_schedule                          -     864    +864
tcp_ack                                     4811    4815      +4
tcp_validate_incoming                        817     815      -2
tcp_collapse                                 860     858      -2
tcp_send_rcvq                                555     353    -202
tcp_data_queue                              3435    3033    -402
tcp_prune_queue                              721       -    -721

Signed-off-by: Pavel Emelyanov 
Acked-by: Eric Dumazet 
Signed-off-by: David S. Miller

tcp: Schedule rmem for rcvq repair send

2012-05-11T03:24:35+00:00

As noted by Eric, no checks are performed on the data size we're
putting in the read queue during repair. Thus, validate the given
data size with the common rmem management routine.

Signed-off-by: Pavel Emelyanov 
Acked-by: Eric Dumazet 
Signed-off-by: David S. Miller