linux/net/ipv4
Neal Cardwell c0638c247f tcp: don't fragment SACKed skbs in tcp_mark_head_lost()
In tcp_mark_head_lost() we should not attempt to fragment a SACKed skb
to mark the first portion as lost. This is for two primary reasons:

(1) tcp_shifted_skb() coalesces adjacent regions of SACKed skbs. When
doing this, it preserves the sum of their packet counts in order to
reflect the real-world dynamics on the wire. But given that skbs can
have remainders that do not align to MSS boundaries, this packet count
preservation means that for SACKed skbs there is not necessarily a
direct linear relationship between tcp_skb_pcount(skb) and
skb->len. Thus tcp_mark_head_lost()'s previous attempts to fragment
off and mark as lost a prefix of length (packets - oldcnt)*mss from
SACKed skbs were leading to occasional failures of the WARN_ON(len >
skb->len) in tcp_fragment() (which used to be a BUG_ON(); see the
recent "crash in tcp_fragment" thread on netdev).

(2) there is no real point in fragmenting off part of a SACKed skb and
calling tcp_skb_mark_lost() on it, since tcp_skb_mark_lost() is a NOP
for SACKed skbs.

Signed-off-by: Neal Cardwell <ncardwell@google.com>
Acked-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Acked-by: Yuchung Cheng <ycheng@google.com>
Acked-by: Nandita Dukkipati <nanditad@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2012-03-03 14:57:59 -05:00
..
netfilter Merge branch 'for-linus' of git://selinuxproject.org/~jmorris/linux-security 2012-01-14 18:36:33 -08:00
af_inet.c per-netns ipv4 sysctl_tcp_mem 2011-12-12 19:04:11 -05:00
ah4.c ah: Don't return NET_XMIT_DROP on input. 2011-11-12 18:13:32 -05:00
arp.c net: Don't proxy arp respond if iif == rt->dst.dev if private VLAN is disabled 2012-02-10 15:13:36 -05:00
cipso_ipv4.c cipso: remove an unneeded NULL check in cipso_v4_doi_add() 2011-10-11 18:43:53 -04:00
datagram.c ipv4: Lock socket and use cork flow in ip4_datagram_connect(). 2011-05-08 13:48:57 -07:00
devinet.c net: reintroduce missing rcu_assign_pointer() calls 2012-01-12 12:26:56 -08:00
esp4.c inet: constify ip headers and in6_addr 2011-04-22 11:04:14 -07:00
fib_frontend.c rtnetlink: Compute and store minimum ifinfo dump size 2011-06-09 20:38:07 -07:00
fib_lookup.h ipv4: Fix nexthop caching wrt. scoping. 2011-03-24 18:06:47 -07:00
fib_rules.c net: ipv4: export fib_lookup and fib_table_lookup 2011-12-04 22:43:33 +01:00
fib_semantics.c ipv4: Fix fib_info->fib_metrics leak 2011-09-16 17:42:26 -04:00
fib_trie.c net: reintroduce missing rcu_assign_pointer() calls 2012-01-12 12:26:56 -08:00
gre.c rcu: convert uses of rcu_assign_pointer(x, NULL) to RCU_INIT_POINTER 2011-08-02 04:29:23 -07:00
icmp.c net: more accurate skb truesize 2011-10-13 16:05:07 -04:00
igmp.c net: reintroduce missing rcu_assign_pointer() calls 2012-01-12 12:26:56 -08:00
inet_connection_sock.c tcp: bind() optimize port allocation 2012-01-25 21:50:43 -05:00
inet_diag.c inet_diag: Rename inet_diag_req_compat into inet_diag_req 2012-01-11 12:56:06 -08:00
inet_fragment.c net/ipv4: EXPORT_SYMBOL cleanups 2010-07-12 12:57:54 -07:00
inet_hashtables.c net: Compute protocol sequence numbers and fragment IDs using MD5. 2011-08-06 18:33:19 -07:00
inet_lro.c net: add skb frag size accessors 2011-10-19 03:10:46 -04:00
inet_timewait_sock.c net: Fix files explicitly needing to include module.h 2011-10-31 19:30:28 -04:00
inetpeer.c inetpeer: initialize ->redirect_genid in inet_getpeer() 2012-01-17 15:52:12 -05:00
ip_forward.c ipv4: Save nexthop address of LSRR/SSRR option to IPCB. 2011-11-23 19:19:32 -05:00
ip_fragment.c treewide: Fix typos in various parts of the kernel, and fix some comments. 2011-12-02 14:57:31 +01:00
ip_gre.c gre: fix spelling in comments 2012-02-24 17:41:11 -05:00
ip_input.c ip: introduce ip_is_fragment helper inline function 2011-06-21 20:33:34 -07:00
ip_options.c ipv4: Fix wrong order of ip_rt_get_source() and update iph->daddr. 2012-02-10 15:12:12 -05:00
ip_output.c net: Rename dst_get_neighbour{, _raw} to dst_get_neighbour_noref{, _raw}. 2011-12-05 15:20:19 -05:00
ip_sockglue.c net: use IS_ENABLED(CONFIG_IPV6) 2011-12-11 18:25:16 -05:00
ipcomp.c inet: constify ip headers and in6_addr 2011-04-22 11:04:14 -07:00
ipconfig.c net: fix some sparse errors 2012-01-17 10:31:12 -05:00
ipip.c net: reintroduce missing rcu_assign_pointer() calls 2012-01-12 12:26:56 -08:00
ipmr.c net: reintroduce missing rcu_assign_pointer() calls 2012-01-12 12:26:56 -08:00
Kconfig net: Fix build regression when INET_UDP_DIAG=y and IPV6=m 2012-02-07 13:35:28 -05:00
Makefile tcp memory pressure controls 2011-12-12 19:04:10 -05:00
netfilter.c netfilter: possible unaligned packet header in ip_route_me_harder 2011-11-21 18:46:18 +01:00
ping.c ipv4: ping: Fix recvmsg MSG_OOB error handling. 2012-02-21 17:59:19 -05:00
proc.c tcp: detect loss above high_seq in recovery 2012-01-22 15:08:44 -05:00
protocol.c net: add __rcu annotations to protocol 2010-10-27 11:37:31 -07:00
raw.c ipv4: Remove all uses of LL_ALLOCATED_SPACE 2011-11-18 14:37:08 -05:00
route.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2011-12-23 17:13:56 -05:00
syncookies.c tcp: Replace constants with #define macros 2011-12-21 01:03:23 -05:00
sysctl_net_ipv4.c tcp: properly initialize tcp memory limits 2012-02-02 14:34:41 -05:00
tcp_bic.c tcp: fix undo after RTO for BIC 2012-01-20 14:17:26 -05:00
tcp_cong.c tcp: do not scale TSO segment size with reordering degree 2011-11-29 00:29:41 -05:00
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_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: mark tcp_congestion_ops read_mostly 2011-03-10 00:40:17 -08:00
tcp_illinois.c tcp: mark tcp_congestion_ops read_mostly 2011-03-10 00:40:17 -08:00
tcp_input.c tcp: don't fragment SACKed skbs in tcp_mark_head_lost() 2012-03-03 14:57:59 -05:00
tcp_ipv4.c tcp_v4_send_reset: binding oif to iif in no sock case 2012-02-04 18:20:05 -05:00
tcp_lp.c Fix common misspellings 2011-03-31 11:26:23 -03:00
tcp_memcontrol.c net: decrement memcg jump label when limit, not usage, is changed 2012-01-12 12:27:59 -08:00
tcp_minisocks.c net: use IS_ENABLED(CONFIG_IPV6) 2011-12-11 18:25:16 -05:00
tcp_output.c tcp: fix tcp_trim_head() to adjust segment count with skb MSS 2012-01-30 12:42:58 -05:00
tcp_probe.c net: ipv4: tcp_probe: cleanup snprintf() use 2010-11-17 12:27:46 -08:00
tcp_scalable.c tcp: mark tcp_congestion_ops read_mostly 2011-03-10 00:40:17 -08:00
tcp_timer.c net: Disambiguate kernel message 2012-02-01 14:41:50 -05:00
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 vfs: fix panic in __d_lookup() with high dentry hashtable counts 2012-02-13 20:45:38 -05:00
tunnel4.c net: use IS_ENABLED(CONFIG_IPV6) 2011-12-11 18:25:16 -05:00
udp_diag.c net: kill duplicate included header 2012-01-17 10:31:12 -05:00
udp_impl.h
udp.c udp: Export code sk lookup routines 2011-12-09 14:14:08 -05:00
udplite.c Merge branch 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux 2011-11-06 19:44:47 -08:00
xfrm4_input.c net/ipv4: EXPORT_SYMBOL cleanups 2010-07-12 12:57:54 -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 ipsec: be careful of non existing mac headers 2012-02-23 16:50:45 -05:00
xfrm4_output.c xfrm4: Don't call icmp_send on local error 2011-07-01 17:33:19 -07:00
xfrm4_policy.c ipv4: fix ipsec forward performance regression 2011-10-24 03:01:22 -04:00
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: use IS_ENABLED(CONFIG_IPV6) 2011-12-11 18:25:16 -05:00