linux/net/ipv4
Jiri Kosina 59ea33a68a tcp: perform DMA to userspace only if there is a task waiting for it
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 <jkosina@suse.cz>
Signed-off-by: David S. Miller <davem@davemloft.net>
2012-07-27 13:45:51 -07:00
..
netfilter ipv4: Adjust semantics of rt->rt_gateway. 2012-07-20 13:31:20 -07:00
af_inet.c net-tcp: Fast Open client - sendmsg(MSG_FASTOPEN) 2012-07-19 11:02:03 -07:00
ah4.c ipv4: Add redirect support to all protocol icmp error handlers. 2012-07-11 21:27:49 -07:00
arp.c ipv4: Fix input route performance regression. 2012-07-26 15:50:39 -07:00
cipso_ipv4.c cipso: don't follow a NULL pointer when setsockopt() is called 2012-07-18 09:01:12 -07:00
datagram.c ipv4: Lock socket and use cork flow in ip4_datagram_connect(). 2011-05-08 13:48:57 -07:00
devinet.c ipv4: Add interface option to enable routing of 127.0.0.0/8 2012-06-12 15:25:46 -07:00
esp4.c ipv4: Add redirect support to all protocol icmp error handlers. 2012-07-11 21:27:49 -07:00
fib_frontend.c ipv4: Remove redundant assignment 2012-07-23 13:00:54 -07:00
fib_lookup.h ipv4: Fix nexthop caching wrt. scoping. 2011-03-24 18:06:47 -07:00
fib_rules.c ipv4: Don't store a rule pointer in fib_result. 2012-07-13 08:21:29 -07:00
fib_semantics.c ipv4: Fix input route performance regression. 2012-07-26 15:50:39 -07:00
fib_trie.c ipv4: Remove tb_peers from fib_table. 2012-07-12 09:39:28 -07:00
gre.c net: ipv4: Standardize prefixes for message logging 2012-03-12 17:05:21 -07:00
icmp.c ipv4: Prepare for change of rt->rt_iif encoding. 2012-07-23 16:36:26 -07:00
igmp.c ipv4: fix checkpatch errors 2012-04-15 12:37:19 -04:00
inet_connection_sock.c ipv4: Kill FLOWI_FLAG_RT_NOCACHE and associated code. 2012-07-20 13:36:54 -07:00
inet_diag.c net: make sock diag per-namespace 2012-07-16 22:31:34 -07:00
inet_fragment.c inetpeer: add parameter net for inet_getpeer_v4,v6 2012-06-08 14:27:23 -07:00
inet_hashtables.c ipv4: fix checkpatch errors 2012-04-15 12:37:19 -04:00
inet_lro.c net: add skb frag size accessors 2011-10-19 03:10:46 -04:00
inet_timewait_sock.c net: ipv4 and ipv6: Convert printk(KERN_DEBUG to pr_debug 2012-05-16 01:01:03 -04:00
inetpeer.c ipv4: Maintain redirect and PMTU info in struct rtable again. 2012-07-10 22:40:14 -07:00
ip_forward.c snmp: fix OutOctets counter to include forwarded datagrams 2012-06-07 14:50:56 -07:00
ip_fragment.c ipv4: Fix input route performance regression. 2012-07-26 15:50:39 -07:00
ip_gre.c ipv4: Adjust semantics of rt->rt_gateway. 2012-07-20 13:31:20 -07:00
ip_input.c ipv6: Early TCP socket demux 2012-07-26 15:50:39 -07:00
ip_options.c ipv4: optimize fib_compute_spec_dst call in ip_options_echo 2012-07-19 08:30:49 -07:00
ip_output.c Merge branch 'kill_rtcache' 2012-07-22 17:04:15 -07:00
ip_sockglue.c ipv4: Prepare for change of rt->rt_iif encoding. 2012-07-23 16:36:26 -07:00
ip_vti.c net/ipv4/ip_vti.c: Fix __rcu warnings detected by sparse. 2012-07-23 13:00:54 -07:00
ipcomp.c ipv4: Add redirect support to all protocol icmp error handlers. 2012-07-11 21:27:49 -07:00
ipconfig.c net/ipv4/ipconfig: neaten __setup placement 2012-05-20 04:06:16 -04:00
ipip.c ipv4: Adjust semantics of rt->rt_gateway. 2012-07-20 13:31:20 -07:00
ipmr.c ipv4: Kill rt->rt_oif 2012-07-20 13:38:34 -07:00
Kconfig net/ipv4: VTI support new module for ip_vti. 2012-07-18 09:36:12 -07:00
Makefile net-tcp: Fast Open base 2012-07-19 10:55:36 -07:00
netfilter.c net: Delete all remaining instances of ctl_path 2012-04-20 21:22:30 -04:00
ping.c ipv4: Add redirect support to all protocol icmp error handlers. 2012-07-11 21:27:49 -07:00
proc.c net-tcp: Fast Open client - sending SYN-data 2012-07-19 11:02:03 -07:00
protocol.c inet: Sanitize inet{,6} protocol demux. 2012-06-19 18:56:21 -07:00
raw.c ipv4: Add redirect support to all protocol icmp error handlers. 2012-07-11 21:27:49 -07:00
route.c ipv4: Fix input route performance regression. 2012-07-26 15:50:39 -07:00
syncookies.c net-tcp: Fast Open base 2012-07-19 10:55:36 -07:00
sysctl_net_ipv4.c net-tcp: Fast Open base 2012-07-19 10:55:36 -07:00
tcp_bic.c tcp: fix undo after RTO for BIC 2012-01-20 14:17:26 -05:00
tcp_cong.c tcp: fix ABC in tcp_slow_start() 2012-07-20 10:59:41 -07:00
tcp_cubic.c tcp: fix undo after RTO for CUBIC 2012-01-20 14:17:26 -05:00
tcp_diag.c inet_diag: Rename inet_diag_req into inet_diag_req_v2 2012-01-11 12:56:06 -08:00
tcp_fastopen.c net-tcp: Fast Open base 2012-07-19 10:55:36 -07:00
tcp_highspeed.c tcp: mark tcp_congestion_ops read_mostly 2011-03-10 00:40:17 -08:00
tcp_htcp.c tcp: mark tcp_congestion_ops read_mostly 2011-03-10 00:40:17 -08:00
tcp_hybla.c tcp: bool conversions 2012-05-17 14:59:59 -04:00
tcp_illinois.c tcp: mark tcp_congestion_ops read_mostly 2011-03-10 00:40:17 -08:00
tcp_input.c tcp: perform DMA to userspace only if there is a task waiting for it 2012-07-27 13:45:51 -07:00
tcp_ipv4.c ipv4: fix TCP early demux 2012-07-27 13:45:51 -07:00
tcp_lp.c Fix common misspellings 2011-03-31 11:26:23 -03:00
tcp_memcontrol.c memcg: decrement static keys at real destroy time 2012-05-29 16:22:28 -07:00
tcp_metrics.c tcp: avoid oops in tcp_metrics and reset tcpm_stamp 2012-07-23 00:57:12 -07:00
tcp_minisocks.c ipv4: fix TCP early demux 2012-07-27 13:45:51 -07:00
tcp_output.c tcp: dont drop MTU reduction indications 2012-07-23 00:58:46 -07:00
tcp_probe.c net: cleanup unsigned to unsigned int 2012-04-15 12:44:40 -04:00
tcp_scalable.c tcp: mark tcp_congestion_ops read_mostly 2011-03-10 00:40:17 -08:00
tcp_timer.c tcp: improve latencies of timer triggered events 2012-07-20 10:59:41 -07:00
tcp_vegas.c tcp: mark tcp_congestion_ops read_mostly 2011-03-10 00:40:17 -08:00
tcp_vegas.h
tcp_veno.c tcp: mark tcp_congestion_ops read_mostly 2011-03-10 00:40:17 -08:00
tcp_westwood.c tcp: mark tcp_congestion_ops read_mostly 2011-03-10 00:40:17 -08:00
tcp_yeah.c Fix common misspellings 2011-03-31 11:26:23 -03:00
tcp.c tcp: Add TCP_USER_TIMEOUT negative value check 2012-07-27 13:45:50 -07:00
tunnel4.c net: Convert printks to pr_<level> 2012-03-11 23:42:51 -07:00
udp_diag.c net: make sock diag per-namespace 2012-07-16 22:31:34 -07:00
udp_impl.h ipv4: fix checkpatch errors 2012-04-15 12:37:19 -04:00
udp.c ipv4: Add redirect support to all protocol icmp error handlers. 2012-07-11 21:27:49 -07:00
udplite.c net: ipv4: Standardize prefixes for message logging 2012-03-12 17:05:21 -07:00
xfrm4_input.c ipv4: Fix input route performance regression. 2012-07-26 15:50:39 -07:00
xfrm4_mode_beet.c ipsec: be careful of non existing mac headers 2012-02-23 16:50:45 -05:00
xfrm4_mode_transport.c
xfrm4_mode_tunnel.c net/ipv4: VTI support rx-path hook in xfrm4_mode_tunnel. 2012-07-18 09:36:12 -07:00
xfrm4_output.c xfrm4: Don't call icmp_send on local error 2011-07-01 17:33:19 -07:00
xfrm4_policy.c ipv4: Turn rt->rt_route_iif into rt->rt_is_input. 2012-07-20 13:40:02 -07:00
xfrm4_state.c net: Add export.h for EXPORT_SYMBOL/THIS_MODULE to non-modules 2011-10-31 19:30:30 -04:00
xfrm4_tunnel.c net: ipv4: Standardize prefixes for message logging 2012-03-12 17:05:21 -07:00