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authorEric Dumazet <eric.dumazet@gmail.com>2011-04-27 22:56:07 +0000
committerDavid S. Miller <davem@davemloft.net>2011-05-02 15:26:28 -0700
commite67f88dd12f610da98ca838822f2c9b4e7c6100e (patch)
tree6cf01b794984aaad97b6e6ff6e5103bc48d68191 /net/core/fib_rules.c
parentdcfd9cdc1222f14d6180514e533289493a0716fb (diff)
downloadlinux-e67f88dd12f610da98ca838822f2c9b4e7c6100e.tar.bz2
net: dont hold rtnl mutex during netlink dump callbacks
Four years ago, Patrick made a change to hold rtnl mutex during netlink dump callbacks. I believe it was a wrong move. This slows down concurrent dumps, making good old /proc/net/ files faster than rtnetlink in some situations. This occurred to me because one "ip link show dev ..." was _very_ slow on a workload adding/removing network devices in background. All dump callbacks are able to use RCU locking now, so this patch does roughly a revert of commits : 1c2d670f366 : [RTNETLINK]: Hold rtnl_mutex during netlink dump callbacks 6313c1e0992 : [RTNETLINK]: Remove unnecessary locking in dump callbacks This let writers fight for rtnl mutex and readers going full speed. It also takes care of phonet : phonet_route_get() is now called from rcu read section. I renamed it to phonet_route_get_rcu() Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Cc: Patrick McHardy <kaber@trash.net> Cc: Remi Denis-Courmont <remi.denis-courmont@nokia.com> Acked-by: Stephen Hemminger <shemminger@vyatta.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core/fib_rules.c')
-rw-r--r--net/core/fib_rules.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/net/core/fib_rules.c b/net/core/fib_rules.c
index 8248ebb5891d..3911586e12e4 100644
--- a/net/core/fib_rules.c
+++ b/net/core/fib_rules.c
@@ -590,7 +590,8 @@ static int dump_rules(struct sk_buff *skb, struct netlink_callback *cb,
int idx = 0;
struct fib_rule *rule;
- list_for_each_entry(rule, &ops->rules_list, list) {
+ rcu_read_lock();
+ list_for_each_entry_rcu(rule, &ops->rules_list, list) {
if (idx < cb->args[1])
goto skip;