ip6mr: remove synchronize_rcu() in favor of SOCK_RCU_FREE

Kirill found that recently added synchronize_rcu() call in
ip6mr_sk_done()
was slowing down netns dismantle and posted a patch to use it only if
the socket
was found.

I instead suggested to get rid of this call, and use instead
SOCK_RCU_FREE

We might later change IPv4 side to use the same technique and unify
both stacks. IPv4 does not use synchronize_rcu() but has a call_rcu()
that could be replaced by SOCK_RCU_FREE.

Tested:
 time for i in {1..1000}; do unshare -n /bin/false;done

 Before : real 7m18.911s
 After : real 10.187s

Fixes: 8571ab479a6e ("ip6mr: Make mroute_sk rcu-based")
Signed-off-by: Eric Dumazet <[email protected]>
Reported-by: Kirill Tkhai <[email protected]>
Cc: Yuval Mintz <[email protected]>
Reviewed-by: Kirill Tkhai <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

0 files changed, 0 insertions, 0 deletions