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authorEric Dumazet <edumazet@google.com>2015-11-18 06:31:02 -0800
committerDavid S. Miller <davem@davemloft.net>2015-11-18 16:17:42 -0500
commit34cbe27e811c591c854a39c0dee1b461bb796953 (patch)
treef9371f25907985feef0b5e9c9d8b0f7ba1eb2432
parent6180d9de61a5c461f9e3efef5417a844701dbbb2 (diff)
downloadlinux-34cbe27e811c591c854a39c0dee1b461bb796953.tar.bz2
net: napi_hash_del() returns a boolean status
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 <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--include/linux/netdevice.h5
-rw-r--r--net/core/dev.c10
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);