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-rw-r--r--net/core/dst.c23
1 files changed, 14 insertions, 9 deletions
diff --git a/net/core/dst.c b/net/core/dst.c
index 960e503..6192f11 100644
--- a/net/core/dst.c
+++ b/net/core/dst.c
@@ -151,13 +151,13 @@ int dst_discard_out(struct net *net, struct sock *sk, struct sk_buff *skb)
}
EXPORT_SYMBOL(dst_discard_out);
-const u32 dst_default_metrics[RTAX_MAX + 1] = {
+const struct dst_metrics dst_default_metrics = {
/* This initializer is needed to force linker to place this variable
* into const section. Otherwise it might end into bss section.
* We really want to avoid false sharing on this variable, and catch
* any writes on it.
*/
- [RTAX_MAX] = 0xdeadbeef,
+ .refcnt = ATOMIC_INIT(1),
};
void dst_init(struct dst_entry *dst, struct dst_ops *ops,
@@ -169,7 +169,7 @@ void dst_init(struct dst_entry *dst, struct dst_ops *ops,
if (dev)
dev_hold(dev);
dst->ops = ops;
- dst_init_metrics(dst, dst_default_metrics, true);
+ dst_init_metrics(dst, dst_default_metrics.metrics, true);
dst->expires = 0UL;
dst->path = dst;
dst->from = NULL;
@@ -314,25 +314,30 @@ EXPORT_SYMBOL(dst_release);
u32 *dst_cow_metrics_generic(struct dst_entry *dst, unsigned long old)
{
- u32 *p = kmalloc(sizeof(u32) * RTAX_MAX, GFP_ATOMIC);
+ struct dst_metrics *p = kmalloc(sizeof(*p), GFP_ATOMIC);
if (p) {
- u32 *old_p = __DST_METRICS_PTR(old);
+ struct dst_metrics *old_p = (struct dst_metrics *)__DST_METRICS_PTR(old);
unsigned long prev, new;
- memcpy(p, old_p, sizeof(u32) * RTAX_MAX);
+ atomic_set(&p->refcnt, 1);
+ memcpy(p->metrics, old_p->metrics, sizeof(p->metrics));
new = (unsigned long) p;
prev = cmpxchg(&dst->_metrics, old, new);
if (prev != old) {
kfree(p);
- p = __DST_METRICS_PTR(prev);
+ p = (struct dst_metrics *)__DST_METRICS_PTR(prev);
if (prev & DST_METRICS_READ_ONLY)
p = NULL;
+ } else if (prev & DST_METRICS_REFCOUNTED) {
+ if (atomic_dec_and_test(&old_p->refcnt))
+ kfree(old_p);
}
}
- return p;
+ BUILD_BUG_ON(offsetof(struct dst_metrics, metrics) != 0);
+ return (u32 *)p;
}
EXPORT_SYMBOL(dst_cow_metrics_generic);
@@ -341,7 +346,7 @@ void __dst_destroy_metrics_generic(struct dst_entry *dst, unsigned long old)
{
unsigned long prev, new;
- new = ((unsigned long) dst_default_metrics) | DST_METRICS_READ_ONLY;
+ new = ((unsigned long) &dst_default_metrics) | DST_METRICS_READ_ONLY;
prev = cmpxchg(&dst->_metrics, old, new);
if (prev == old)
kfree(__DST_METRICS_PTR(old));
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