krealloc(NULL, ..) is same as kmalloc(), so we can avoid special-casing
the initial allocation after the prealloc removal (we had to use
->alloc_len as the initial allocation size).
This also means we do not zero the preallocated memory anymore; only
offsets[]. Existing code makes sure the new (used) extension space gets
zeroed out.
Signed-off-by: Florian Westphal <f...@strlen.de>
---
changes since v1:
- don't use RCU_INIT_POINTER().
real fix would be to add '__rcu' annotation to nf_conn->ext, but that
seems excessive given we'd like to get rid of rcu for nf_ct_ext...
net/netfilter/nf_conntrack_extend.c | 51 +++++++++++--------------------------
1 file changed, 15 insertions(+), 36 deletions(-)
diff --git a/net/netfilter/nf_conntrack_extend.c
b/net/netfilter/nf_conntrack_extend.c
index 5c66816eb965..68ae1be08ed8 100644
--- a/net/netfilter/nf_conntrack_extend.c
+++ b/net/netfilter/nf_conntrack_extend.c
@@ -44,49 +44,24 @@ void __nf_ct_ext_destroy(struct nf_conn *ct)
}
EXPORT_SYMBOL(__nf_ct_ext_destroy);
-static void *
-nf_ct_ext_create(struct nf_ct_ext **ext, enum nf_ct_ext_id id, gfp_t gfp)
-{
- unsigned int off, len, alloc;
- struct nf_ct_ext_type *t;
-
- rcu_read_lock();
- t = rcu_dereference(nf_ct_ext_types[id]);
- if (!t) {
- rcu_read_unlock();
- return NULL;
- }
-
- off = ALIGN(sizeof(struct nf_ct_ext), t->align);
- len = off + t->len;
- rcu_read_unlock();
-
- alloc = max(len, NF_CT_EXT_PREALLOC);
- *ext = kzalloc(alloc, gfp);
- if (!*ext)
- return NULL;
-
- (*ext)->offset[id] = off;
- (*ext)->len = len;
-
- return (void *)(*ext) + off;
-}
-
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;
- int newlen, newoff;
struct nf_ct_ext_type *t;
/* Conntrack must not be confirmed to avoid races on reallocation. */
NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
old = ct->ext;
- if (!old)
- return nf_ct_ext_create(&ct->ext, id, gfp);
- if (__nf_ct_ext_exist(old, id))
- return NULL;
+ if (old) {
+ if (__nf_ct_ext_exist(old, id))
+ return NULL;
+ oldlen = old->len;
+ } else {
+ oldlen = sizeof(*new);
+ }
rcu_read_lock();
t = rcu_dereference(nf_ct_ext_types[id]);
@@ -95,15 +70,19 @@ void *nf_ct_ext_add(struct nf_conn *ct, enum nf_ct_ext_id
id, gfp_t gfp)
return NULL;
}
- newoff = ALIGN(old->len, t->align);
+ newoff = ALIGN(oldlen, t->align);
newlen = newoff + t->len;
rcu_read_unlock();
- new = __krealloc(old, newlen, gfp);
+ alloc = max(newlen, NF_CT_EXT_PREALLOC);
+ new = __krealloc(old, alloc, gfp);
if (!new)
return NULL;
- if (new != old) {
+ if (!old) {
+ memset(new->offset, 0, sizeof(new->offset));
+ ct->ext = new;
+ } else if (new != old) {
kfree_rcu(old, rcu);
rcu_assign_pointer(ct->ext, new);
}
--
2.10.2
--
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