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ipvs: free ip_vs_dest structs when refcnt=0

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Currently, the ip_vs_dest cache frees ip_vs_dest objects when their
reference count becomes < 0.  Aside from not being semantically sound,
this is problematic for the new type refcount_t, which will be introduced
shortly in a separate patch. refcount_t is the new kernel type for
holding reference counts, and provides overflow protection and a
constrained interface relative to atomic_t (the type currently being
used for kernel reference counts).

Per Julian Anastasov: "The problem is that dest_trash currently holds
deleted dests (unlinked from RCU lists) with refcnt=0."  Changing
dest_trash to hold dest with refcnt=1 will allow us to free ip_vs_dest
structs when their refcnt=0, in ip_vs_dest_put_and_free().

Signed-off-by: David Windsor <dwindsor@gmail.com>
Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
David Windsor
2017-01-23 22:24:29 -05:00
committed by Pablo Neira Ayuso
parent a9e419dc7b
commit 90c1aff702
2 changed files with 4 additions and 6 deletions
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2
include/net/ip_vs.h
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@@ -1421,7 +1421,7 @@ static inline void ip_vs_dest_put(struct ip_vs_dest *dest)
static inline void ip_vs_dest_put_and_free(struct ip_vs_dest *dest)
{
if (atomic_dec_return(&dest->refcnt) < 0)
if (atomic_dec_and_test(&dest->refcnt))
kfree(dest);
}