napi_hash_del() will soon be used from both drivers (if they want)
or core networking stack.
Callers are responsibles to ensure an RCU grace period is respected
before freeing napi structure : napi_hash_del() can signal if
this RCU grace period is needed or not.
Signed-off-by: Eric Dumazet <eduma...@google.com>
---
include/linux/netdevice.h | 5 +++--
net/core/dev.c | 10 +++++++---
2 files changed, 10 insertions(+), 5 deletions(-)
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 838935d1cdbb..e5c33b29471b 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -474,9 +474,10 @@ void napi_hash_add(struct napi_struct *napi);
* @napi: napi context
*
* Warning: caller must observe rcu grace period
- * before freeing memory containing @napi
+ * before freeing memory containing @napi, if
+ * this function returns true.
*/
-void napi_hash_del(struct napi_struct *napi);
+bool napi_hash_del(struct napi_struct *napi);
/**
* napi_disable - prevent NAPI from scheduling
diff --git a/net/core/dev.c b/net/core/dev.c
index 02dfbd91a8e4..59dddac1c2e7 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4760,14 +4760,18 @@ EXPORT_SYMBOL_GPL(napi_hash_add);
/* Warning : caller is responsible to make sure rcu grace period
* is respected before freeing memory containing @napi
*/
-void napi_hash_del(struct napi_struct *napi)
+bool napi_hash_del(struct napi_struct *napi)
{
+ bool rcu_sync_needed = false;
+
spin_lock(&napi_hash_lock);
- if (test_and_clear_bit(NAPI_STATE_HASHED, &napi->state))
+ if (test_and_clear_bit(NAPI_STATE_HASHED, &napi->state)) {
+ rcu_sync_needed = true;
hlist_del_rcu(&napi->napi_hash_node);
-
+ }
spin_unlock(&napi_hash_lock);
+ return rcu_sync_needed;
}
EXPORT_SYMBOL_GPL(napi_hash_del);
--
2.6.0.rc2.230.g3dd15c0
--
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