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@iki.fi>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/flow.c b/net/core/flow.c
index 1d27ca6..521df52 100644
--- a/net/core/flow.c
+++ b/net/core/flow.c
@@ -26,17 +26,16 @@
#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_object *object;
};
struct flow_cache_percpu {
- struct flow_cache_entry ** hash_table;
+ struct flow_cache_entry **hash_table;
int hash_count;
u32 hash_rnd;
int hash_rnd_recalc;
@@ -44,7 +43,7 @@
};
struct flow_flush_info {
- struct flow_cache * cache;
+ struct flow_cache *cache;
atomic_t cpuleft;
struct completion completion;
};
@@ -52,7 +51,7 @@
struct flow_cache {
u32 hash_shift;
unsigned long order;
- struct flow_cache_percpu * percpu;
+ struct flow_cache_percpu *percpu;
struct notifier_block hotcpu_notifier;
int low_watermark;
int high_watermark;
@@ -78,12 +77,21 @@
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->object && !fle->object->ops->check(fle->object))
+ 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);
+ fle->object->ops->delete(fle->object);
kmem_cache_free(flow_cachep, fle);
fcp->hash_count--;
}
@@ -96,16 +104,18 @@
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 @@
return 0;
}
-void *flow_cache_lookup(struct net *net, struct flowi *key, u16 family, u8 dir,
- flow_resolve_t resolver)
+struct flow_cache_object *
+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_object *flo;
unsigned int hash;
local_bh_disable();
fcp = per_cpu_ptr(fc->percpu, smp_processor_id());
fle = NULL;
+ flo = NULL;
/* Packet really early in init? Making flow_cache_init a
* pre-smp initcall would solve this. --RR */
if (!fcp->hash_table)
@@ -185,27 +198,17 @@
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) {
+ if (unlikely(!fle)) {
if (fcp->hash_count > fc->high_watermark)
flow_cache_shrink(fc, fcp);
@@ -219,33 +222,39 @@
fle->object = NULL;
fcp->hash_count++;
}
+ } else if (likely(fle->genid == atomic_read(&flow_cache_genid))) {
+ flo = fle->object;
+ if (!flo)
+ goto ret_object;
+ flo = flo->ops->get(flo);
+ if (flo)
+ goto ret_object;
+ } else if (fle->object) {
+ flo = fle->object;
+ flo->ops->delete(flo);
+ fle->object = NULL;
}
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);
- }
- local_bh_enable();
-
- if (err)
- obj = ERR_PTR(err);
- return obj;
+ flo = NULL;
+ if (fle) {
+ flo = fle->object;
+ fle->object = NULL;
}
+ flo = resolver(net, key, family, dir, flo, ctx);
+ if (fle) {
+ fle->genid = atomic_read(&flow_cache_genid);
+ if (!IS_ERR(flo))
+ fle->object = flo;
+ else
+ fle->genid--;
+ } else {
+ if (flo && !IS_ERR(flo))
+ flo->ops->delete(flo);
+ }
+ret_object:
+ local_bh_enable();
+ return flo;
}
static void flow_cache_flush_tasklet(unsigned long data)
@@ -261,13 +270,12 @@
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;
+ if (fle->object)
+ fle->object->ops->delete(fle->object);
fle->object = NULL;
- atomic_dec(fle->object_ref);
}
}