Ying Xue f9a2c80b8b tipc: introduce new spinlock to protect struct link_req ... Currently, only 'bearer_lock' is used to protect struct link_req in the function disc_timeout(). This is unsafe, since the member fields 'num_nodes' and 'timer_intv' might be accessed by below three different threads simultaneously, none of them grabbing bearer_lock in the critical region: link_activate() tipc_bearer_add_dest() tipc_disc_add_dest() req->num_nodes++; tipc_link_reset() tipc_bearer_remove_dest() tipc_disc_remove_dest() req->num_nodes-- disc_update() read req->num_nodes write req->timer_intv disc_timeout() read req->num_nodes read/write req->timer_intv Without lock protection, the only symptom of a race is that discovery messages occasionally may not be sent out. This is not fatal, since such messages are best-effort anyway. On the other hand, since discovery messages are not time critical, adding a protecting lock brings no serious overhead either. So we add a new, dedicated spinlock in order to guarantee absolute data consistency in link_req objects. This also helps reduce the overall role of the bearer_lock, which we want to remove completely in a later commit series. Signed-off-by: Ying Xue <ying.xue@windriver.com> Reviewed-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>		2014-01-07 18:44:25 -05:00
..
addr.c
addr.h
bcast.c
bcast.h
bearer.c
bearer.h
config.c
config.h
core.c
core.h
discover.c	tipc: introduce new spinlock to protect struct link_req	2014-01-07 18:44:25 -05:00
discover.h
eth_media.c
handler.c
ib_media.c
Kconfig
link.c
link.h
log.c
Makefile
msg.c
msg.h
name_distr.c
name_distr.h
name_table.c
name_table.h
net.c
net.h
netlink.c
node_subscr.c
node_subscr.h
node.c
node.h
port.c
port.h
ref.c
ref.h
server.c
server.h
socket.c
subscr.c
subscr.h
sysctl.c