Introduce a new API raw_notifier_chain_cond_register to
add a notifier to a raw notifier chain, only if notifier
not already present in the chain.
Signed-off-by: Jenny TC <jenny...@intel.com>
---
v1
* Added API definition
v2
* Added API decalarion
include/linux/notifier.h | 2 ++
kernel/notifier.c | 18 ++++++++++++++++++
2 files changed, 20 insertions(+)
diff --git a/include/linux/notifier.h b/include/linux/notifier.h
index d65746e..67895f0 100644
--- a/include/linux/notifier.h
+++ b/include/linux/notifier.h
@@ -124,6 +124,8 @@ extern int srcu_notifier_chain_register(struct
srcu_notifier_head *nh,
extern int blocking_notifier_chain_cond_register(
struct blocking_notifier_head *nh,
struct notifier_block *nb);
+extern int raw_notifier_chain_cond_register(struct raw_notifier_head *nh,
+ struct notifier_block *nb);
extern int atomic_notifier_chain_unregister(struct atomic_notifier_head *nh,
struct notifier_block *nb);
diff --git a/kernel/notifier.c b/kernel/notifier.c
index 2d5cc4c..267e26f 100644
--- a/kernel/notifier.c
+++ b/kernel/notifier.c
@@ -349,6 +349,24 @@ int raw_notifier_chain_register(struct raw_notifier_head
*nh,
EXPORT_SYMBOL_GPL(raw_notifier_chain_register);
/**
+ * raw_notifier_chain_cond_register - Cond add notifier to a raw notifier
chain
+ * @nh: Pointer to head of the raw notifier chain
+ * @n: New entry in notifier chain
+ *
+ * Adds a notifier to a raw notifier chain, only if not already
+ * present in the chain.
+ * All locking must be provided by the caller.
+ *
+ * Currently always returns zero.
+ */
+int raw_notifier_chain_cond_register(struct raw_notifier_head *nh,
+ struct notifier_block *n)
+{
+ return notifier_chain_cond_register(&nh->head, n);
+}
+EXPORT_SYMBOL_GPL(raw_notifier_chain_cond_register);
+
+/**
* raw_notifier_chain_unregister - Remove notifier from a raw notifier
chain
* @nh: Pointer to head of the raw notifier chain
* @n: Entry to remove from notifier chain
--
1.7.9.5
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