linux/net/tipc
Jon Maloy e654f9f53b tipc: clean up skb list lock handling on send path
The policy for handling the skb list locks on the send and receive paths
is simple.

- On the send path we never need to grab the lock on the 'xmitq' list
  when the destination is an exernal node.

- On the receive path we always need to grab the lock on the 'inputq'
  list, irrespective of source node.

However, when transmitting node local messages those will eventually
end up on the receive path of a local socket, meaning that the argument
'xmitq' in tipc_node_xmit() will become the 'ínputq' argument in  the
function tipc_sk_rcv(). This has been handled by always initializing
the spinlock of the 'xmitq' list at message creation, just in case it
may end up on the receive path later, and despite knowing that the lock
in most cases never will be used.

This approach is inaccurate and confusing, and has also concealed the
fact that the stated 'no lock grabbing' policy for the send path is
violated in some cases.

We now clean up this by never initializing the lock at message creation,
instead doing this at the moment we find that the message actually will
enter the receive path. At the same time we fix the four locations
where we incorrectly access the spinlock on the send/error path.

This patch also reverts commit d12cffe932 ("tipc: ensure head->lock
is initialised") which has now become redundant.

CC: Eric Dumazet <edumazet@google.com>
Reported-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Acked-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Reviewed-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-08-18 14:01:07 -07:00
..
addr.c
addr.h
bcast.c tipc: clean up skb list lock handling on send path 2019-08-18 14:01:07 -07:00
bcast.h tipc: fix a null pointer deref 2019-03-21 09:56:55 -07:00
bearer.c tipc: add loopback device tracking 2019-08-08 22:11:39 -07:00
bearer.h tipc: add loopback device tracking 2019-08-08 22:11:39 -07:00
core.c tipc: add loopback device tracking 2019-08-08 22:11:39 -07:00
core.h tipc: add loopback device tracking 2019-08-08 22:11:39 -07:00
diag.c
discover.c
discover.h
eth_media.c
group.c tipc: clean up skb list lock handling on send path 2019-08-18 14:01:07 -07:00
group.h
ib_media.c
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
link.c tipc: clean up skb list lock handling on send path 2019-08-18 14:01:07 -07:00
link.h tipc: fix missing Name entries due to half-failover 2019-05-04 00:59:51 -04:00
Makefile
monitor.c netlink: make nla_nest_start() add NLA_F_NESTED flag 2019-04-27 17:03:44 -04:00
monitor.h
msg.c tipc: fix changeover issues due to large packet 2019-07-25 15:55:47 -07:00
msg.h tipc: fix changeover issues due to large packet 2019-07-25 15:55:47 -07:00
name_distr.c tipc: clean up skb list lock handling on send path 2019-08-18 14:01:07 -07:00
name_distr.h
name_table.c netlink: make nla_nest_start() add NLA_F_NESTED flag 2019-04-27 17:03:44 -04:00
name_table.h
net.c netlink: make validation more configurable for future strictness 2019-04-27 17:07:21 -04:00
net.h
netlink_compat.c tipc: compat: allow tipc commands without arguments 2019-08-01 18:14:00 -04:00
netlink.c tipc: fix missing indentation in source code 2019-06-24 07:29:45 -07:00
netlink.h
node.c tipc: clean up skb list lock handling on send path 2019-08-18 14:01:07 -07:00
node.h tipc: optimize link synching mechanism 2019-07-25 15:55:47 -07:00
socket.c tipc: clean up skb list lock handling on send path 2019-08-18 14:01:07 -07:00
socket.h
subscr.c
subscr.h tipc: fix modprobe tipc failed after switch order of device registration 2019-05-20 10:45:43 -07:00
sysctl.c proc/sysctl: add shared variables for range check 2019-07-18 17:08:07 -07:00
topsrv.c tipc: add loopback device tracking 2019-08-08 22:11:39 -07:00
topsrv.h
trace.c tipc: remove unneeded semicolon in trace.c 2019-01-17 22:04:43 -08:00
trace.h
udp_media.c tipc: use rcu dereference functions properly 2019-07-07 13:18:53 -07:00
udp_media.h