netns: protect netns ID lookups with RCU

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__peernet2id() can be protected by RCU as it only calls idr_for_each(),
which is RCU-safe, and never modifies the nsid table.

rtnl_net_dumpid() can also do lockless lookups. It does two nested
idr_for_each() calls on nsid tables (one direct call and one indirect
call because of rtnl_net_dumpid_one() calling __peernet2id()). The
netnsid tables are never updated. Therefore it is safe to not take the
nsid_lock and run within an RCU-critical section instead.

Signed-off-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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Guillaume Nault 2020-01-13 22:39:22 +01:00 • committed by David S. Miller

parent 4905294162

commit 2dce224f46

1 changed files with 7 additions and 15 deletions

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net/core/net_namespace.c

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