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authorHerbert Xu <herbert@gondor.apana.org.au>2006-05-27 23:03:58 -0700
committerDavid S. Miller <davem@sunset.davemloft.net>2006-06-17 21:28:37 -0700
commit546be2405be119ef55467aace45f337a16e5d424 (patch)
tree9b09f0041f9f82a20ab25ace3c7360e4a4b7989f /net/xfrm/xfrm_policy.c
parent9cb3528cdbffc513eb9fb8faa45d41e397355830 (diff)
downloadop-kernel-dev-546be2405be119ef55467aace45f337a16e5d424.zip
op-kernel-dev-546be2405be119ef55467aace45f337a16e5d424.tar.gz
[IPSEC] xfrm: Undo afinfo lock proliferation
The number of locks used to manage afinfo structures can easily be reduced down to one each for policy and state respectively. This is based on the observation that the write locks are only held by module insertion/removal which are very rare events so there is no need to further differentiate between the insertion of modules like ipv6 versus esp6. The removal of the read locks in xfrm4_policy.c/xfrm6_policy.c might look suspicious at first. However, after you realise that nobody ever takes the corresponding write lock you'll feel better :) As far as I can gather it's an attempt to guard against the removal of the corresponding modules. Since neither module can be unloaded at all we can leave it to whoever fixes up IPv6 unloading :) Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/xfrm/xfrm_policy.c')
-rw-r--r--net/xfrm/xfrm_policy.c58
1 files changed, 34 insertions, 24 deletions
diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index b469c8b..44b64a5 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -46,45 +46,43 @@ static DEFINE_SPINLOCK(xfrm_policy_gc_lock);
static struct xfrm_policy_afinfo *xfrm_policy_get_afinfo(unsigned short family);
static void xfrm_policy_put_afinfo(struct xfrm_policy_afinfo *afinfo);
+static struct xfrm_policy_afinfo *xfrm_policy_lock_afinfo(unsigned int family);
+static void xfrm_policy_unlock_afinfo(struct xfrm_policy_afinfo *afinfo);
int xfrm_register_type(struct xfrm_type *type, unsigned short family)
{
- struct xfrm_policy_afinfo *afinfo = xfrm_policy_get_afinfo(family);
- struct xfrm_type_map *typemap;
+ struct xfrm_policy_afinfo *afinfo = xfrm_policy_lock_afinfo(family);
+ struct xfrm_type **typemap;
int err = 0;
if (unlikely(afinfo == NULL))
return -EAFNOSUPPORT;
typemap = afinfo->type_map;
- write_lock_bh(&typemap->lock);
- if (likely(typemap->map[type->proto] == NULL))
- typemap->map[type->proto] = type;
+ if (likely(typemap[type->proto] == NULL))
+ typemap[type->proto] = type;
else
err = -EEXIST;
- write_unlock_bh(&typemap->lock);
- xfrm_policy_put_afinfo(afinfo);
+ xfrm_policy_unlock_afinfo(afinfo);
return err;
}
EXPORT_SYMBOL(xfrm_register_type);
int xfrm_unregister_type(struct xfrm_type *type, unsigned short family)
{
- struct xfrm_policy_afinfo *afinfo = xfrm_policy_get_afinfo(family);
- struct xfrm_type_map *typemap;
+ struct xfrm_policy_afinfo *afinfo = xfrm_policy_lock_afinfo(family);
+ struct xfrm_type **typemap;
int err = 0;
if (unlikely(afinfo == NULL))
return -EAFNOSUPPORT;
typemap = afinfo->type_map;
- write_lock_bh(&typemap->lock);
- if (unlikely(typemap->map[type->proto] != type))
+ if (unlikely(typemap[type->proto] != type))
err = -ENOENT;
else
- typemap->map[type->proto] = NULL;
- write_unlock_bh(&typemap->lock);
- xfrm_policy_put_afinfo(afinfo);
+ typemap[type->proto] = NULL;
+ xfrm_policy_unlock_afinfo(afinfo);
return err;
}
EXPORT_SYMBOL(xfrm_unregister_type);
@@ -92,7 +90,7 @@ EXPORT_SYMBOL(xfrm_unregister_type);
struct xfrm_type *xfrm_get_type(u8 proto, unsigned short family)
{
struct xfrm_policy_afinfo *afinfo;
- struct xfrm_type_map *typemap;
+ struct xfrm_type **typemap;
struct xfrm_type *type;
int modload_attempted = 0;
@@ -102,11 +100,9 @@ retry:
return NULL;
typemap = afinfo->type_map;
- read_lock(&typemap->lock);
- type = typemap->map[proto];
+ type = typemap[proto];
if (unlikely(type && !try_module_get(type->owner)))
type = NULL;
- read_unlock(&typemap->lock);
if (!type && !modload_attempted) {
xfrm_policy_put_afinfo(afinfo);
request_module("xfrm-type-%d-%d",
@@ -1306,17 +1302,31 @@ static struct xfrm_policy_afinfo *xfrm_policy_get_afinfo(unsigned short family)
return NULL;
read_lock(&xfrm_policy_afinfo_lock);
afinfo = xfrm_policy_afinfo[family];
- if (likely(afinfo != NULL))
- read_lock(&afinfo->lock);
- read_unlock(&xfrm_policy_afinfo_lock);
+ if (unlikely(!afinfo))
+ read_unlock(&xfrm_policy_afinfo_lock);
return afinfo;
}
static void xfrm_policy_put_afinfo(struct xfrm_policy_afinfo *afinfo)
{
- if (unlikely(afinfo == NULL))
- return;
- read_unlock(&afinfo->lock);
+ read_unlock(&xfrm_policy_afinfo_lock);
+}
+
+static struct xfrm_policy_afinfo *xfrm_policy_lock_afinfo(unsigned int family)
+{
+ struct xfrm_policy_afinfo *afinfo;
+ if (unlikely(family >= NPROTO))
+ return NULL;
+ write_lock_bh(&xfrm_policy_afinfo_lock);
+ afinfo = xfrm_policy_afinfo[family];
+ if (unlikely(!afinfo))
+ write_unlock_bh(&xfrm_policy_afinfo_lock);
+ return afinfo;
+}
+
+static void xfrm_policy_unlock_afinfo(struct xfrm_policy_afinfo *afinfo)
+{
+ write_unlock_bh(&xfrm_policy_afinfo_lock);
}
static int xfrm_dev_event(struct notifier_block *this, unsigned long event, void *ptr)
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