linux/net/ipv4
Jason Baron ce5ec44099 tcp: ensure epoll edge trigger wakeup when write queue is empty
We currently rely on the setting of SOCK_NOSPACE in the write()
path to ensure that we wake up any epoll edge trigger waiters when
acks return to free space in the write queue. However, if we fail
to allocate even a single skb in the write queue, we could end up
waiting indefinitely.

Fix this by explicitly issuing a wakeup when we detect the condition
of an empty write queue and a return value of -EAGAIN. This allows
userspace to re-try as we expect this to be a temporary failure.

I've tested this approach by artificially making
sk_stream_alloc_skb() return NULL periodically. In that case,
epoll edge trigger waiters will hang indefinitely in epoll_wait()
without this patch.

Signed-off-by: Jason Baron <jbaron@akamai.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-05-21 18:52:47 -04:00
..
netfilter Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf-next 2015-05-18 14:47:36 -04:00
af_inet.c net: Modify sk_alloc to not reference count the netns of kernel sockets. 2015-05-11 10:50:18 -04:00
ah4.c ipsec: Remove obsolete MAX_AH_AUTH_LEN 2014-09-18 10:54:36 +02:00
arp.c netfilter: Pass socket pointer down through okfn(). 2015-04-07 15:25:55 -04:00
cipso_ipv4.c ipv4: coding style: comparison for inequality with NULL 2015-04-03 12:11:15 -04:00
datagram.c net: Save TX flow hash in sock and set in skbuf on xmit 2014-07-07 21:14:21 -07:00
devinet.c ipv4: coding style: comparison for inequality with NULL 2015-04-03 12:11:15 -04:00
esp4.c ipv4: coding style: comparison for equality with NULL 2015-04-03 12:11:15 -04:00
fib_frontend.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2015-04-06 22:34:15 -04:00
fib_lookup.h ipv4: FIB Local/MAIN table collapse 2015-03-11 16:22:14 -04:00
fib_rules.c ipv4: coding style: comparison for equality with NULL 2015-04-03 12:11:15 -04:00
fib_semantics.c ipv4: remove the unnecessary codes in fib_info_hash_move 2015-05-02 22:17:44 -04:00
fib_trie.c switchdev: s/netdev_switch_/switchdev_/ and s/NETDEV_SWITCH_/SWITCHDEV_/ 2015-05-12 18:43:52 -04:00
fou.c fou: avoid missing unlock in failure path 2015-04-16 12:11:19 -04:00
geneve_core.c geneve_core: identify as driver library in modules description 2015-05-13 15:59:13 -04:00
gre_demux.c net: Fix GRE RX to use skb_transport_header for GRE header offset 2014-09-08 15:23:05 -07:00
gre_offload.c ipv4: coding style: comparison for inequality with NULL 2015-04-03 12:11:15 -04:00
icmp.c ipv4: coding style: comparison for equality with NULL 2015-04-03 12:11:15 -04:00
igmp.c net: Export IGMP/MLD message validation code 2015-05-04 14:49:23 -04:00
inet_connection_sock.c inet: fix possible panic in reqsk_queue_unlink() 2015-04-24 11:39:15 -04:00
inet_diag.c tcp: prepare CC get_info() access from getsockopt() 2015-04-29 17:10:38 -04:00
inet_fragment.c ipv4: coding style: comparison for equality with NULL 2015-04-03 12:11:15 -04:00
inet_hashtables.c tcp/dccp: get rid of central timewait timer 2015-04-13 16:40:05 -04:00
inet_lro.c lro: remove dead code 2013-12-29 16:34:25 -05:00
inet_timewait_sock.c tcp/dccp: tw_timer_handler() is static 2015-05-13 15:21:33 -04:00
inetpeer.c inet: remove dead inetpeer sequence code 2014-09-08 16:42:42 -07:00
ip_forward.c ip_forward: Drop frames with attached skb->sk 2015-04-20 14:07:33 -04:00
ip_fragment.c IPv4: skip ICMP for bridge contrack users when defrag expires 2015-05-19 00:15:27 -04:00
ip_gre.c ipv4: coding style: comparison for equality with NULL 2015-04-03 12:11:15 -04:00
ip_input.c netfilter: Pass socket pointer down through okfn(). 2015-04-07 15:25:55 -04:00
ip_options.c ipv4: coding style: comparison for inequality with NULL 2015-04-03 12:11:15 -04:00
ip_output.c bridge_netfilter: No ICMP packet on IPv4 fragmentation error 2015-05-19 00:15:39 -04:00
ip_sockglue.c ipv4: coding style: comparison for inequality with NULL 2015-04-03 12:11:15 -04:00
ip_tunnel_core.c ip_tunnel: Report Rx dropped in ip_tunnel_get_stats64 2015-05-14 22:30:54 -04:00
ip_tunnel.c udp_tunnel: Pass UDP socket down through udp_tunnel{, 6}_xmit_skb(). 2015-04-07 15:29:08 -04:00
ip_vti.c ipv4: coding style: comparison for inequality with NULL 2015-04-03 12:11:15 -04:00
ipcomp.c ipv4: coding style: comparison for equality with NULL 2015-04-03 12:11:15 -04:00
ipconfig.c ipv4: coding style: comparison for equality with NULL 2015-04-03 12:11:15 -04:00
ipip.c ipip: fix one sparse error 2015-05-17 13:08:29 -04:00
ipmr.c netfilter: Pass socket pointer down through okfn(). 2015-04-07 15:25:55 -04:00
Kconfig geneve: Rename support library as geneve_core 2015-05-13 15:59:13 -04:00
Makefile geneve: Rename support library as geneve_core 2015-05-13 15:59:13 -04:00
netfilter.c netfilter: Use nf_hook_state in nf_queue_entry. 2015-04-04 12:25:22 -04:00
ping.c ipv4: Missing sk_nulls_node_init() in ping_unhash(). 2015-05-01 22:02:47 -04:00
proc.c tcp: add TCPWinProbe and TCPKeepAlive SNMP counters 2015-05-09 16:42:32 -04:00
protocol.c net: Export inet_offloads and inet6_offloads 2014-09-19 17:15:31 -04:00
raw.c Merge branch 'for-davem' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-04-13 18:18:05 -04:00
route.c net: ipv4: route: Fix sending IGMP messages with link address 2015-05-04 00:04:08 -04:00
syncookies.c tcp: fix ipv4 mapped request socks 2015-03-25 00:57:48 -04:00
sysctl_net_ipv4.c tcp: add rfc3168, section 6.1.1.1. fallback 2015-05-19 16:53:37 -04:00
tcp_bic.c tcp: stretch ACK fixes prep 2015-01-28 22:18:37 -08:00
tcp_cong.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2015-03-20 18:51:09 -04:00
tcp_cubic.c tcp: restore 1.5x per RTT limit to CUBIC cwnd growth in congestion avoidance 2015-03-11 16:51:51 -04:00
tcp_dctcp.c tcp: prepare CC get_info() access from getsockopt() 2015-04-29 17:10:38 -04:00
tcp_diag.c ipv4: coding style: comparison for inequality with NULL 2015-04-03 12:11:15 -04:00
tcp_fastopen.c tcp: add tcpi_bytes_received to tcp_info 2015-04-29 17:10:37 -04:00
tcp_highspeed.c tcp: whitespace fixes 2014-09-01 18:12:45 -07:00
tcp_htcp.c tcp: whitespace fixes 2014-09-01 18:12:45 -07:00
tcp_hybla.c tcp: whitespace fixes 2014-09-01 18:12:45 -07:00
tcp_illinois.c tcp: prepare CC get_info() access from getsockopt() 2015-04-29 17:10:38 -04:00
tcp_input.c tcp: allow one skb to be received per socket under memory pressure 2015-05-17 22:45:49 -04:00
tcp_ipv4.c tcp: add rfc3168, section 6.1.1.1. fallback 2015-05-19 16:53:37 -04:00
tcp_lp.c tcp: remove in_flight parameter from cong_avoid() methods 2014-05-03 19:23:07 -04:00
tcp_memcontrol.c memcg: cleanup static keys decrement 2015-02-12 18:54:10 -08:00
tcp_metrics.c tcp: RFC7413 option support for Fast Open client 2015-04-07 18:36:39 -04:00
tcp_minisocks.c tcp: provide SYN headers for passive connections 2015-05-05 16:02:34 -04:00
tcp_offload.c tcp: cleanup static functions 2015-02-28 16:56:51 -05:00
tcp_output.c tcp: add a force_schedule argument to sk_stream_alloc_skb() 2015-05-21 16:56:40 -04:00
tcp_probe.c tcp: whitespace fixes 2014-09-01 18:12:45 -07:00
tcp_scalable.c tcp: stretch ACK fixes prep 2015-01-28 22:18:37 -08:00
tcp_timer.c tcp: introduce tcp_under_memory_pressure() 2015-05-17 22:45:48 -04:00
tcp_vegas.c tcp: prepare CC get_info() access from getsockopt() 2015-04-29 17:10:38 -04:00
tcp_vegas.h tcp: prepare CC get_info() access from getsockopt() 2015-04-29 17:10:38 -04:00
tcp_veno.c tcp: stretch ACK fixes prep 2015-01-28 22:18:37 -08:00
tcp_westwood.c tcp_westwood: fix tcp_westwood_info() 2015-04-30 00:27:44 -04:00
tcp_yeah.c tcp: stretch ACK fixes prep 2015-01-28 22:18:37 -08:00
tcp.c tcp: ensure epoll edge trigger wakeup when write queue is empty 2015-05-21 18:52:47 -04:00
tunnel4.c
udp_diag.c ipv4: coding style: comparison for equality with NULL 2015-04-03 12:11:15 -04:00
udp_impl.h net: Remove iocb argument from sendmsg and recvmsg 2015-03-02 13:06:31 -05:00
udp_offload.c ipv4: coding style: comparison for inequality with NULL 2015-04-03 12:11:15 -04:00
udp_tunnel.c net: Modify sk_alloc to not reference count the netns of kernel sockets. 2015-05-11 10:50:18 -04:00
udp.c net: remove extra newlines 2015-04-07 22:24:37 -04:00
udplite.c net: Eliminate no_check from protosw 2014-05-23 16:28:53 -04:00
xfrm4_input.c netfilter: Pass socket pointer down through okfn(). 2015-04-07 15:25:55 -04:00
xfrm4_mode_beet.c ipv4: ERROR: code indent should use tabs where possible 2013-12-26 13:43:21 -05:00
xfrm4_mode_transport.c
xfrm4_mode_tunnel.c ipv4: hash net ptr into fragmentation bucket selection 2015-03-25 14:07:04 -04:00
xfrm4_output.c netfilter: Pass socket pointer down through okfn(). 2015-04-07 15:25:55 -04:00
xfrm4_policy.c ipv4: coding style: comparison for equality with NULL 2015-04-03 12:11:15 -04:00
xfrm4_protocol.c xfrm4: Remove duplicate semicolon 2014-06-30 07:49:47 +02:00
xfrm4_state.c inet: make no_pmtu_disc per namespace and kill ipv4_config 2013-12-18 16:58:20 -05:00
xfrm4_tunnel.c