Instead of waiting for rcu grace period just free it directly.
This is safe because conntrack lookup doesn't consider extensions.
Other accesses happen while ct->ext can't be free'd, either because
a ct refcount was taken or because the conntrack hash bucket lock or
the dying list spinlock have been taken.
This allows to remove __krealloc in a followup patch, netfilter was the
only user.
Signed-off-by: Florian Westphal <fw@xxxxxxxxx>
---
include/net/netfilter/nf_conntrack_extend.h | 10 ----------
net/netfilter/nf_conntrack_core.c | 2 --
net/netfilter/nf_conntrack_extend.c | 21 ++++++++++-----------
3 files changed, 10 insertions(+), 23 deletions(-)
diff --git a/include/net/netfilter/nf_conntrack_extend.h b/include/net/netfilter/nf_conntrack_extend.h
index 112a6f40dfaf..5ae5295aa46d 100644
--- a/include/net/netfilter/nf_conntrack_extend.h
+++ b/include/net/netfilter/nf_conntrack_extend.h
@@ -43,7 +43,6 @@ enum nf_ct_ext_id {
/* Extensions: optional stuff which isn't permanently in struct. */
struct nf_ct_ext {
- struct rcu_head rcu;
u8 offset[NF_CT_EXT_NUM];
u8 len;
char data[0];
@@ -72,15 +71,6 @@ static inline void *__nf_ct_ext_find(const struct nf_conn *ct, u8 id)
/* Destroy all relationships */
void nf_ct_ext_destroy(struct nf_conn *ct);
-/* Free operation. If you want to free a object referred from private area,
- * please implement __nf_ct_ext_free() and call it.
- */
-static inline void nf_ct_ext_free(struct nf_conn *ct)
-{
- if (ct->ext)
- kfree_rcu(ct->ext, rcu);
-}
-
/* Add this type, returns pointer to data or NULL. */
void *nf_ct_ext_add(struct nf_conn *ct, enum nf_ct_ext_id id, gfp_t gfp);
diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index 0c63120b2db2..bcccaa7ec34c 100644
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -573,7 +573,6 @@ EXPORT_SYMBOL_GPL(nf_ct_tmpl_alloc);
void nf_ct_tmpl_free(struct nf_conn *tmpl)
{
nf_ct_ext_destroy(tmpl);
- nf_ct_ext_free(tmpl);
if (ARCH_KMALLOC_MINALIGN <= NFCT_INFOMASK)
kfree((char *)tmpl - tmpl->proto.tmpl_padto);
@@ -1417,7 +1416,6 @@ void nf_conntrack_free(struct nf_conn *ct)
WARN_ON(atomic_read(&ct->ct_general.use) != 0);
nf_ct_ext_destroy(ct);
- nf_ct_ext_free(ct);
kmem_cache_free(nf_conntrack_cachep, ct);
smp_mb__before_atomic();
atomic_dec(&net->ct.count);
diff --git a/net/netfilter/nf_conntrack_extend.c b/net/netfilter/nf_conntrack_extend.c
index d4ed1e197921..c24e5b64b00c 100644
--- a/net/netfilter/nf_conntrack_extend.c
+++ b/net/netfilter/nf_conntrack_extend.c
@@ -34,21 +34,24 @@ void nf_ct_ext_destroy(struct nf_conn *ct)
t->destroy(ct);
rcu_read_unlock();
}
+
+ kfree(ct->ext);
}
EXPORT_SYMBOL(nf_ct_ext_destroy);
void *nf_ct_ext_add(struct nf_conn *ct, enum nf_ct_ext_id id, gfp_t gfp)
{
unsigned int newlen, newoff, oldlen, alloc;
- struct nf_ct_ext *old, *new;
struct nf_ct_ext_type *t;
+ struct nf_ct_ext *new;
/* Conntrack must not be confirmed to avoid races on reallocation. */
WARN_ON(nf_ct_is_confirmed(ct));
- old = ct->ext;
- if (old) {
+ if (ct->ext) {
+ const struct nf_ct_ext *old = ct->ext;
+
if (__nf_ct_ext_exist(old, id))
return NULL;
oldlen = old->len;
@@ -68,22 +71,18 @@ void *nf_ct_ext_add(struct nf_conn *ct, enum nf_ct_ext_id id, gfp_t gfp)
rcu_read_unlock();
alloc = max(newlen, NF_CT_EXT_PREALLOC);
- kmemleak_not_leak(old);
- new = __krealloc(old, alloc, gfp);
+ new = krealloc(ct->ext, alloc, gfp);
if (!new)
return NULL;
- if (!old) {
+ if (!ct->ext)
memset(new->offset, 0, sizeof(new->offset));
- ct->ext = new;
- } else if (new != old) {
- kfree_rcu(old, rcu);
- rcu_assign_pointer(ct->ext, new);
- }
new->offset[id] = newoff;
new->len = newlen;
memset((void *)new + newoff, 0, newlen - newoff);
+
+ ct->ext = new;
return (void *)new + newoff;
}
EXPORT_SYMBOL(nf_ct_ext_add);
--
2.21.0
