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Message-Id: <1270126340-30181-2-git-send-email-timo.teras@iki.fi>
Date: Thu, 1 Apr 2010 15:52:17 +0300
From: Timo Teras <timo.teras@....fi>
To: netdev@...r.kernel.org
Cc: Herbert Xu <herbert@...dor.apana.org.au>,
Timo Teras <timo.teras@....fi>
Subject: [PATCH 1/4] flow: virtualize flow cache entry methods
This allows to validate the cached object before returning it.
It also allows to destruct object properly, if the last reference
was held in flow cache. This is also a prepartion for caching
bundles in the flow cache.
In return for virtualizing the methods, we save on:
- not having to regenerate the whole flow cache on policy removal:
each flow matching a killed policy gets refreshed as the getter
function notices it smartly.
- we do not have to call flow_cache_flush from policy gc, since the
flow cache now properly deletes the object if it had any references
Signed-off-by: Timo Teras <timo.teras@....fi>
---
include/net/flow.h | 18 ++++++--
include/net/xfrm.h | 2 +
net/core/flow.c | 118 ++++++++++++++++++++++++-----------------------
net/xfrm/xfrm_policy.c | 113 ++++++++++++++++++++++++++++++---------------
4 files changed, 151 insertions(+), 100 deletions(-)
diff --git a/include/net/flow.h b/include/net/flow.h
index 809970b..65d68a6 100644
--- a/include/net/flow.h
+++ b/include/net/flow.h
@@ -86,11 +86,21 @@ struct flowi {
struct net;
struct sock;
-typedef int (*flow_resolve_t)(struct net *net, struct flowi *key, u16 family,
- u8 dir, void **objp, atomic_t **obj_refp);
-extern void *flow_cache_lookup(struct net *net, struct flowi *key, u16 family,
- u8 dir, flow_resolve_t resolver);
+struct flow_cache_entry_ops {
+ struct flow_cache_entry_ops ** (*get)(struct flow_cache_entry_ops **);
+ int (*check)(struct flow_cache_entry_ops **);
+ void (*delete)(struct flow_cache_entry_ops **);
+};
+
+typedef struct flow_cache_entry_ops **(*flow_resolve_t)(
+ struct net *net, struct flowi *key, u16 family,
+ u8 dir, struct flow_cache_entry_ops **old_ops, void *ctx);
+
+extern struct flow_cache_entry_ops **flow_cache_lookup(
+ struct net *net, struct flowi *key, u16 family,
+ u8 dir, flow_resolve_t resolver, void *ctx);
+
extern void flow_cache_flush(void);
extern atomic_t flow_cache_genid;
diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index d74e080..cb8934b 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -19,6 +19,7 @@
#include <net/route.h>
#include <net/ipv6.h>
#include <net/ip6_fib.h>
+#include <net/flow.h>
#include <linux/interrupt.h>
@@ -481,6 +482,7 @@ struct xfrm_policy {
atomic_t refcnt;
struct timer_list timer;
+ struct flow_cache_entry_ops *fc_ops;
u32 priority;
u32 index;
struct xfrm_mark mark;
diff --git a/net/core/flow.c b/net/core/flow.c
index 1d27ca6..f938137 100644
--- a/net/core/flow.c
+++ b/net/core/flow.c
@@ -26,13 +26,12 @@
#include <linux/security.h>
struct flow_cache_entry {
- struct flow_cache_entry *next;
- u16 family;
- u8 dir;
- u32 genid;
- struct flowi key;
- void *object;
- atomic_t *object_ref;
+ struct flow_cache_entry * next;
+ u16 family;
+ u8 dir;
+ u32 genid;
+ struct flowi key;
+ struct flow_cache_entry_ops ** ops;
};
struct flow_cache_percpu {
@@ -78,12 +77,21 @@ static void flow_cache_new_hashrnd(unsigned long arg)
add_timer(&fc->rnd_timer);
}
+static int flow_entry_valid(struct flow_cache_entry *fle)
+{
+ if (atomic_read(&flow_cache_genid) != fle->genid)
+ return 0;
+ if (fle->ops && !(*fle->ops)->check(fle->ops))
+ return 0;
+ return 1;
+}
+
static void flow_entry_kill(struct flow_cache *fc,
struct flow_cache_percpu *fcp,
struct flow_cache_entry *fle)
{
- if (fle->object)
- atomic_dec(fle->object_ref);
+ if (fle->ops)
+ (*fle->ops)->delete(fle->ops);
kmem_cache_free(flow_cachep, fle);
fcp->hash_count--;
}
@@ -96,16 +104,18 @@ static void __flow_cache_shrink(struct flow_cache *fc,
int i;
for (i = 0; i < flow_cache_hash_size(fc); i++) {
- int k = 0;
+ int saved = 0;
flp = &fcp->hash_table[i];
- while ((fle = *flp) != NULL && k < shrink_to) {
- k++;
- flp = &fle->next;
- }
while ((fle = *flp) != NULL) {
- *flp = fle->next;
- flow_entry_kill(fc, fcp, fle);
+ if (saved < shrink_to &&
+ flow_entry_valid(fle)) {
+ saved++;
+ flp = &fle->next;
+ } else {
+ *flp = fle->next;
+ flow_entry_kill(fc, fcp, fle);
+ }
}
}
}
@@ -166,18 +176,21 @@ static int flow_key_compare(struct flowi *key1, struct flowi *key2)
return 0;
}
-void *flow_cache_lookup(struct net *net, struct flowi *key, u16 family, u8 dir,
- flow_resolve_t resolver)
+struct flow_cache_entry_ops **flow_cache_lookup(
+ struct net *net, struct flowi *key, u16 family, u8 dir,
+ flow_resolve_t resolver, void *ctx)
{
struct flow_cache *fc = &flow_cache_global;
struct flow_cache_percpu *fcp;
struct flow_cache_entry *fle, **head;
+ struct flow_cache_entry_ops **ops;
unsigned int hash;
local_bh_disable();
fcp = per_cpu_ptr(fc->percpu, smp_processor_id());
fle = NULL;
+ ops = NULL;
/* Packet really early in init? Making flow_cache_init a
* pre-smp initcall would solve this. --RR */
if (!fcp->hash_table)
@@ -185,24 +198,14 @@ void *flow_cache_lookup(struct net *net, struct flowi *key, u16 family, u8 dir,
if (fcp->hash_rnd_recalc)
flow_new_hash_rnd(fc, fcp);
- hash = flow_hash_code(fc, fcp, key);
+ hash = flow_hash_code(fc, fcp, key);
head = &fcp->hash_table[hash];
for (fle = *head; fle; fle = fle->next) {
if (fle->family == family &&
fle->dir == dir &&
- flow_key_compare(key, &fle->key) == 0) {
- if (fle->genid == atomic_read(&flow_cache_genid)) {
- void *ret = fle->object;
-
- if (ret)
- atomic_inc(fle->object_ref);
- local_bh_enable();
-
- return ret;
- }
+ flow_key_compare(key, &fle->key) == 0)
break;
- }
}
if (!fle) {
@@ -215,37 +218,37 @@ void *flow_cache_lookup(struct net *net, struct flowi *key, u16 family, u8 dir,
*head = fle;
fle->family = family;
fle->dir = dir;
+ fle->ops = NULL;
memcpy(&fle->key, key, sizeof(*key));
- fle->object = NULL;
+ fle->ops = NULL;
fcp->hash_count++;
}
+ } else if (fle->genid == atomic_read(&flow_cache_genid)) {
+ ops = fle->ops;
+ if (!ops)
+ goto ret_ops;
+ ops = (*ops)->get(ops);
+ if (ops)
+ goto ret_ops;
}
nocache:
- {
- int err;
- void *obj;
- atomic_t *obj_ref;
-
- err = resolver(net, key, family, dir, &obj, &obj_ref);
-
- if (fle && !err) {
- fle->genid = atomic_read(&flow_cache_genid);
-
- if (fle->object)
- atomic_dec(fle->object_ref);
-
- fle->object = obj;
- fle->object_ref = obj_ref;
- if (obj)
- atomic_inc(fle->object_ref);
+ ops = resolver(net, key, family, dir, fle ? fle->ops : NULL, ctx);
+ if (fle) {
+ fle->genid = atomic_read(&flow_cache_genid);
+ if (IS_ERR(ops)) {
+ fle->genid--;
+ fle->ops = NULL;
+ } else {
+ fle->ops = ops;
}
- local_bh_enable();
-
- if (err)
- obj = ERR_PTR(err);
- return obj;
+ } else {
+ if (ops && !IS_ERR(ops))
+ (*ops)->delete(ops);
}
+ret_ops:
+ local_bh_enable();
+ return ops;
}
static void flow_cache_flush_tasklet(unsigned long data)
@@ -261,13 +264,12 @@ static void flow_cache_flush_tasklet(unsigned long data)
fle = fcp->hash_table[i];
for (; fle; fle = fle->next) {
- unsigned genid = atomic_read(&flow_cache_genid);
-
- if (!fle->object || fle->genid == genid)
+ if (flow_entry_valid(fle))
continue;
- fle->object = NULL;
- atomic_dec(fle->object_ref);
+ if (fle->ops)
+ (*fle->ops)->delete(fle->ops);
+ fle->ops = NULL;
}
}
diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index 82789cf..20f5b01 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -216,6 +216,36 @@ expired:
xfrm_pol_put(xp);
}
+static struct flow_cache_entry_ops **xfrm_policy_get_fce(
+ struct flow_cache_entry_ops **ops)
+{
+ struct xfrm_policy *pol = container_of(ops, struct xfrm_policy, fc_ops);
+
+ if (unlikely(pol->walk.dead))
+ ops = NULL;
+ else
+ xfrm_pol_hold(pol);
+
+ return ops;
+}
+
+static int xfrm_policy_check_fce(struct flow_cache_entry_ops **ops)
+{
+ struct xfrm_policy *pol = container_of(ops, struct xfrm_policy, fc_ops);
+
+ return !pol->walk.dead;
+}
+
+static void xfrm_policy_delete_fce(struct flow_cache_entry_ops **ops)
+{
+ xfrm_pol_put(container_of(ops, struct xfrm_policy, fc_ops));
+}
+
+static struct flow_cache_entry_ops xfrm_policy_fc_ops __read_mostly = {
+ .get = xfrm_policy_get_fce,
+ .check = xfrm_policy_check_fce,
+ .delete = xfrm_policy_delete_fce,
+};
/* Allocate xfrm_policy. Not used here, it is supposed to be used by pfkeyv2
* SPD calls.
@@ -236,6 +266,7 @@ struct xfrm_policy *xfrm_policy_alloc(struct net *net, gfp_t gfp)
atomic_set(&policy->refcnt, 1);
setup_timer(&policy->timer, xfrm_policy_timer,
(unsigned long)policy);
+ policy->fc_ops = &xfrm_policy_fc_ops;
}
return policy;
}
@@ -269,9 +300,6 @@ static void xfrm_policy_gc_kill(struct xfrm_policy *policy)
if (del_timer(&policy->timer))
atomic_dec(&policy->refcnt);
- if (atomic_read(&policy->refcnt) > 1)
- flow_cache_flush();
-
xfrm_pol_put(policy);
}
@@ -661,10 +689,8 @@ struct xfrm_policy *xfrm_policy_bysel_ctx(struct net *net, u32 mark, u8 type,
}
write_unlock_bh(&xfrm_policy_lock);
- if (ret && delete) {
- atomic_inc(&flow_cache_genid);
+ if (ret && delete)
xfrm_policy_kill(ret);
- }
return ret;
}
EXPORT_SYMBOL(xfrm_policy_bysel_ctx);
@@ -703,10 +729,8 @@ struct xfrm_policy *xfrm_policy_byid(struct net *net, u32 mark, u8 type,
}
write_unlock_bh(&xfrm_policy_lock);
- if (ret && delete) {
- atomic_inc(&flow_cache_genid);
+ if (ret && delete)
xfrm_policy_kill(ret);
- }
return ret;
}
EXPORT_SYMBOL(xfrm_policy_byid);
@@ -822,7 +846,6 @@ int xfrm_policy_flush(struct net *net, u8 type, struct xfrm_audit *audit_info)
}
if (!cnt)
err = -ESRCH;
- atomic_inc(&flow_cache_genid);
out:
write_unlock_bh(&xfrm_policy_lock);
return err;
@@ -976,32 +999,35 @@ fail:
return ret;
}
-static int xfrm_policy_lookup(struct net *net, struct flowi *fl, u16 family,
- u8 dir, void **objp, atomic_t **obj_refp)
+static struct flow_cache_entry_ops **xfrm_policy_lookup(
+ struct net *net, struct flowi *fl, u16 family,
+ u8 dir, struct flow_cache_entry_ops **old_ops, void *ctx)
{
struct xfrm_policy *pol;
- int err = 0;
+
+ if (old_ops)
+ xfrm_pol_put(container_of(old_ops, struct xfrm_policy, fc_ops));
#ifdef CONFIG_XFRM_SUB_POLICY
pol = xfrm_policy_lookup_bytype(net, XFRM_POLICY_TYPE_SUB, fl, family, dir);
- if (IS_ERR(pol)) {
- err = PTR_ERR(pol);
- pol = NULL;
- }
- if (pol || err)
- goto end;
+ if (IS_ERR(pol))
+ return ERR_CAST(pol);
+ if (pol)
+ goto found;
#endif
pol = xfrm_policy_lookup_bytype(net, XFRM_POLICY_TYPE_MAIN, fl, family, dir);
- if (IS_ERR(pol)) {
- err = PTR_ERR(pol);
- pol = NULL;
- }
-#ifdef CONFIG_XFRM_SUB_POLICY
-end:
-#endif
- if ((*objp = (void *) pol) != NULL)
- *obj_refp = &pol->refcnt;
- return err;
+ if (IS_ERR(pol))
+ return ERR_CAST(pol);
+ if (pol)
+ goto found;
+ return NULL;
+
+found:
+ /* Resolver returns two references:
+ * one for cache and one for caller of flow_cache_lookup() */
+ xfrm_pol_hold(pol);
+
+ return &pol->fc_ops;
}
static inline int policy_to_flow_dir(int dir)
@@ -1091,8 +1117,6 @@ int xfrm_policy_delete(struct xfrm_policy *pol, int dir)
pol = __xfrm_policy_unlink(pol, dir);
write_unlock_bh(&xfrm_policy_lock);
if (pol) {
- if (dir < XFRM_POLICY_MAX)
- atomic_inc(&flow_cache_genid);
xfrm_policy_kill(pol);
return 0;
}
@@ -1578,18 +1602,24 @@ restart:
}
if (!policy) {
+ struct flow_cache_entry_ops **ops;
+
/* To accelerate a bit... */
if ((dst_orig->flags & DST_NOXFRM) ||
!net->xfrm.policy_count[XFRM_POLICY_OUT])
goto nopol;
- policy = flow_cache_lookup(net, fl, dst_orig->ops->family,
- dir, xfrm_policy_lookup);
- err = PTR_ERR(policy);
- if (IS_ERR(policy)) {
+ ops = flow_cache_lookup(net, fl, dst_orig->ops->family,
+ dir, xfrm_policy_lookup, NULL);
+ err = PTR_ERR(ops);
+ if (IS_ERR(ops)) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTPOLERROR);
goto dropdst;
}
+ if (ops)
+ policy = container_of(ops, struct xfrm_policy, fc_ops);
+ else
+ policy = NULL;
}
if (!policy)
@@ -1939,9 +1969,16 @@ int __xfrm_policy_check(struct sock *sk, int dir, struct sk_buff *skb,
}
}
- if (!pol)
- pol = flow_cache_lookup(net, &fl, family, fl_dir,
- xfrm_policy_lookup);
+ if (!pol) {
+ struct flow_cache_entry_ops **ops;
+
+ ops = flow_cache_lookup(net, &fl, family, fl_dir,
+ xfrm_policy_lookup, NULL);
+ if (IS_ERR(ops))
+ pol = ERR_CAST(ops);
+ else if (ops)
+ pol = container_of(ops, struct xfrm_policy, fc_ops);
+ }
if (IS_ERR(pol)) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMINPOLERROR);
--
1.6.3.3
--
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