linux/net/dccp
Eric Dumazet b6c6712a42 net: sk_dst_cache RCUification
With latest CONFIG_PROVE_RCU stuff, I felt more comfortable to make this
work.

sk->sk_dst_cache is currently protected by a rwlock (sk_dst_lock)

This rwlock is readlocked for a very small amount of time, and dst
entries are already freed after RCU grace period. This calls for RCU
again :)

This patch converts sk_dst_lock to a spinlock, and use RCU for readers.

__sk_dst_get() is supposed to be called with rcu_read_lock() or if
socket locked by user, so use appropriate rcu_dereference_check()
condition (rcu_read_lock_held() || sock_owned_by_user(sk))

This patch avoids two atomic ops per tx packet on UDP connected sockets,
for example, and permits sk_dst_lock to be much less dirtied.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-04-13 01:41:33 -07:00
..
ccids Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 2010-04-11 14:53:53 -07:00
ackvec.c dccp: Set per-connection CCIDs via socket options 2008-11-23 16:02:31 -08:00
ackvec.h dccp: Minimise header option overhead in setting the MPS 2009-03-02 03:07:23 -08:00
ccid.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
ccid.h dccp: fix bug in cache allocation 2010-02-03 19:00:30 -08:00
dccp.h inet: Remove unused send_check length argument 2010-04-11 15:29:09 -07:00
diag.c dccp_diag: LISTEN sockets don't have CCIDs 2008-12-17 16:08:01 -08:00
feat.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
feat.h dccp: Debugging functions for feature negotiation 2009-01-21 14:34:05 -08:00
input.c Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 2010-04-11 14:53:53 -07:00
ipv4.c inet: Remove unused send_check length argument 2010-04-11 15:29:09 -07:00
ipv6.c inet: Remove unused send_check length argument 2010-04-11 15:29:09 -07:00
ipv6.h
Kconfig dccp: Lockless integration of CCID congestion-control plugins 2009-01-04 21:42:53 -08:00
Makefile dccp: Integrate the TFRC library with DCCP 2009-01-04 21:45:33 -08:00
minisocks.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
options.c dccp: Debugging functions for feature negotiation 2009-01-21 14:34:05 -08:00
output.c inet: Remove unused send_check length argument 2010-04-11 15:29:09 -07:00
probe.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
proto.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
sysctl.c sysctl net: Remove unused binary sysctl code 2009-11-12 02:05:06 -08:00
timer.c net: sk_dst_cache RCUification 2010-04-13 01:41:33 -07:00