xfrm: policy: prepare policy_bydst hash for rcu lookups

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Since commit 56f047305d
("xfrm: add rcu grace period in xfrm_policy_destroy()") xfrm policy
objects are already free'd via rcu.

In order to make more places lockless (i.e. use rcu_read_lock instead of
grabbing read-side of policy rwlock) we only need to:

- use rcu_assign_pointer to store address of new hash table backend memory
- add rcu barrier so that freeing of old memory is delayed (expansion
  and free happens from system workqueue, so synchronize_rcu is fine)
- use rcu_dereference to fetch current address of the hash table.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

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Florian Westphal 2016-08-11 15:17:53 +02:00 • committed by Steffen Klassert

parent a5eefc1df6

commit e1e551bc56

1 changed files with 14 additions and 6 deletions

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net/xfrm/xfrm_policy.c

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