• Timo Teräs's avatar
    xfrm: remove policy lock when accessing policy->walk.dead · ea2dea9d
    Timo Teräs authored
    All of the code considers ->dead as a hint that the cached policy
    needs to get refreshed. The read side can just drop the read lock
    without any side effects.
    
    The write side needs to make sure that it's written only exactly
    once. Only possible race is at xfrm_policy_kill(). This is fixed
    by checking result of __xfrm_policy_unlink() when needed. It will
    always succeed if the policy object is looked up from the hash
    list (so some checks are removed), but it needs to be checked if
    we are trying to unlink policy via a reference (appropriate
    checks added).
    
    Since policy->walk.dead is written exactly once, it no longer
    needs to be protected with a write lock.
    Signed-off-by: default avatarTimo Teras <timo.teras@iki.fi>
    Acked-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    ea2dea9d
xfrm_user.c 66 KB