Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 243 insertions, 0 deletions

diff --git a/include/linux/notifier.h b/include/linux/notifier.h
new file mode 100644
index 000000000..45702bdcb
--- /dev/null
+++ b/include/linux/notifier.h
@@ -0,0 +1,243 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ *	Routines to manage notifier chains for passing status changes to any
+ *	interested routines. We need this instead of hard coded call lists so
+ *	that modules can poke their nose into the innards. The network devices
+ *	needed them so here they are for the rest of you.
+ *
+ *				Alan Cox <Alan.Cox@linux.org>
+ */
+ 
+#ifndef _LINUX_NOTIFIER_H
+#define _LINUX_NOTIFIER_H
+#include <linux/errno.h>
+#include <linux/mutex.h>
+#include <linux/rwsem.h>
+#include <linux/srcu.h>
+
+/*
+ * Notifier chains are of four types:
+ *
+ *	Atomic notifier chains: Chain callbacks run in interrupt/atomic
+ *		context. Callouts are not allowed to block.
+ *	Blocking notifier chains: Chain callbacks run in process context.
+ *		Callouts are allowed to block.
+ *	Raw notifier chains: There are no restrictions on callbacks,
+ *		registration, or unregistration.  All locking and protection
+ *		must be provided by the caller.
+ *	SRCU notifier chains: A variant of blocking notifier chains, with
+ *		the same restrictions.
+ *
+ * atomic_notifier_chain_register() may be called from an atomic context,
+ * but blocking_notifier_chain_register() and srcu_notifier_chain_register()
+ * must be called from a process context.  Ditto for the corresponding
+ * _unregister() routines.
+ *
+ * atomic_notifier_chain_unregister(), blocking_notifier_chain_unregister(),
+ * and srcu_notifier_chain_unregister() _must not_ be called from within
+ * the call chain.
+ *
+ * SRCU notifier chains are an alternative form of blocking notifier chains.
+ * They use SRCU (Sleepable Read-Copy Update) instead of rw-semaphores for
+ * protection of the chain links.  This means there is _very_ low overhead
+ * in srcu_notifier_call_chain(): no cache bounces and no memory barriers.
+ * As compensation, srcu_notifier_chain_unregister() is rather expensive.
+ * SRCU notifier chains should be used when the chain will be called very
+ * often but notifier_blocks will seldom be removed.
+ */
+
+struct notifier_block;
+
+typedef	int (*notifier_fn_t)(struct notifier_block *nb,
+			unsigned long action, void *data);
+
+struct notifier_block {
+	notifier_fn_t notifier_call;
+	struct notifier_block __rcu *next;
+	int priority;
+};
+
+struct atomic_notifier_head {
+	spinlock_t lock;
+	struct notifier_block __rcu *head;
+};
+
+struct blocking_notifier_head {
+	struct rw_semaphore rwsem;
+	struct notifier_block __rcu *head;
+};
+
+struct raw_notifier_head {
+	struct notifier_block __rcu *head;
+};
+
+struct srcu_notifier_head {
+	struct mutex mutex;
+	struct srcu_usage srcuu;
+	struct srcu_struct srcu;
+	struct notifier_block __rcu *head;
+};
+
+#define ATOMIC_INIT_NOTIFIER_HEAD(name) do {	\
+		spin_lock_init(&(name)->lock);	\
+		(name)->head = NULL;		\
+	} while (0)
+#define BLOCKING_INIT_NOTIFIER_HEAD(name) do {	\
+		init_rwsem(&(name)->rwsem);	\
+		(name)->head = NULL;		\
+	} while (0)
+#define RAW_INIT_NOTIFIER_HEAD(name) do {	\
+		(name)->head = NULL;		\
+	} while (0)
+
+/* srcu_notifier_heads must be cleaned up dynamically */
+extern void srcu_init_notifier_head(struct srcu_notifier_head *nh);
+#define srcu_cleanup_notifier_head(name)	\
+		cleanup_srcu_struct(&(name)->srcu);
+
+#define ATOMIC_NOTIFIER_INIT(name) {				\
+		.lock = __SPIN_LOCK_UNLOCKED(name.lock),	\
+		.head = NULL }
+#define BLOCKING_NOTIFIER_INIT(name) {				\
+		.rwsem = __RWSEM_INITIALIZER((name).rwsem),	\
+		.head = NULL }
+#define RAW_NOTIFIER_INIT(name)	{				\
+		.head = NULL }
+
+#define SRCU_NOTIFIER_INIT(name, pcpu)				\
+	{							\
+		.mutex = __MUTEX_INITIALIZER(name.mutex),	\
+		.head = NULL,					\
+		.srcuu = __SRCU_USAGE_INIT(name.srcuu),		\
+		.srcu = __SRCU_STRUCT_INIT(name.srcu, name.srcuu, pcpu), \
+	}
+
+#define ATOMIC_NOTIFIER_HEAD(name)				\
+	struct atomic_notifier_head name =			\
+		ATOMIC_NOTIFIER_INIT(name)
+#define BLOCKING_NOTIFIER_HEAD(name)				\
+	struct blocking_notifier_head name =			\
+		BLOCKING_NOTIFIER_INIT(name)
+#define RAW_NOTIFIER_HEAD(name)					\
+	struct raw_notifier_head name =				\
+		RAW_NOTIFIER_INIT(name)
+
+#ifdef CONFIG_TREE_SRCU
+#define _SRCU_NOTIFIER_HEAD(name, mod)				\
+	static DEFINE_PER_CPU(struct srcu_data, name##_head_srcu_data); \
+	mod struct srcu_notifier_head name =			\
+			SRCU_NOTIFIER_INIT(name, name##_head_srcu_data)
+
+#else
+#define _SRCU_NOTIFIER_HEAD(name, mod)				\
+	mod struct srcu_notifier_head name =			\
+			SRCU_NOTIFIER_INIT(name, name)
+
+#endif
+
+#define SRCU_NOTIFIER_HEAD(name)				\
+	_SRCU_NOTIFIER_HEAD(name, /* not static */)
+
+#define SRCU_NOTIFIER_HEAD_STATIC(name)				\
+	_SRCU_NOTIFIER_HEAD(name, static)
+
+#ifdef __KERNEL__
+
+extern int atomic_notifier_chain_register(struct atomic_notifier_head *nh,
+		struct notifier_block *nb);
+extern int blocking_notifier_chain_register(struct blocking_notifier_head *nh,
+		struct notifier_block *nb);
+extern int raw_notifier_chain_register(struct raw_notifier_head *nh,
+		struct notifier_block *nb);
+extern int srcu_notifier_chain_register(struct srcu_notifier_head *nh,
+		struct notifier_block *nb);
+
+extern int atomic_notifier_chain_register_unique_prio(
+		struct atomic_notifier_head *nh, struct notifier_block *nb);
+extern int blocking_notifier_chain_register_unique_prio(
+		struct blocking_notifier_head *nh, struct notifier_block *nb);
+
+extern int atomic_notifier_chain_unregister(struct atomic_notifier_head *nh,
+		struct notifier_block *nb);
+extern int blocking_notifier_chain_unregister(struct blocking_notifier_head *nh,
+		struct notifier_block *nb);
+extern int raw_notifier_chain_unregister(struct raw_notifier_head *nh,
+		struct notifier_block *nb);
+extern int srcu_notifier_chain_unregister(struct srcu_notifier_head *nh,
+		struct notifier_block *nb);
+
+extern int atomic_notifier_call_chain(struct atomic_notifier_head *nh,
+		unsigned long val, void *v);
+extern int blocking_notifier_call_chain(struct blocking_notifier_head *nh,
+		unsigned long val, void *v);
+extern int raw_notifier_call_chain(struct raw_notifier_head *nh,
+		unsigned long val, void *v);
+extern int srcu_notifier_call_chain(struct srcu_notifier_head *nh,
+		unsigned long val, void *v);
+
+extern int blocking_notifier_call_chain_robust(struct blocking_notifier_head *nh,
+		unsigned long val_up, unsigned long val_down, void *v);
+extern int raw_notifier_call_chain_robust(struct raw_notifier_head *nh,
+		unsigned long val_up, unsigned long val_down, void *v);
+
+extern bool atomic_notifier_call_chain_is_empty(struct atomic_notifier_head *nh);
+
+#define NOTIFY_DONE		0x0000		/* Don't care */
+#define NOTIFY_OK		0x0001		/* Suits me */
+#define NOTIFY_STOP_MASK	0x8000		/* Don't call further */
+#define NOTIFY_BAD		(NOTIFY_STOP_MASK|0x0002)
+						/* Bad/Veto action */
+/*
+ * Clean way to return from the notifier and stop further calls.
+ */
+#define NOTIFY_STOP		(NOTIFY_OK|NOTIFY_STOP_MASK)
+
+/* Encapsulate (negative) errno value (in particular, NOTIFY_BAD <=> EPERM). */
+static inline int notifier_from_errno(int err)
+{
+	if (err)
+		return NOTIFY_STOP_MASK | (NOTIFY_OK - err);
+
+	return NOTIFY_OK;
+}
+
+/* Restore (negative) errno value from notify return value. */
+static inline int notifier_to_errno(int ret)
+{
+	ret &= ~NOTIFY_STOP_MASK;
+	return ret > NOTIFY_OK ? NOTIFY_OK - ret : 0;
+}
+
+/*
+ *	Declared notifiers so far. I can imagine quite a few more chains
+ *	over time (eg laptop power reset chains, reboot chain (to clean 
+ *	device units up), device [un]mount chain, module load/unload chain,
+ *	low memory chain, screenblank chain (for plug in modular screenblankers) 
+ *	VC switch chains (for loadable kernel svgalib VC switch helpers) etc...
+ */
+ 
+/* CPU notfiers are defined in include/linux/cpu.h. */
+
+/* netdevice notifiers are defined in include/linux/netdevice.h */
+
+/* reboot notifiers are defined in include/linux/reboot.h. */
+
+/* Hibernation and suspend events are defined in include/linux/suspend.h. */
+
+/* Virtual Terminal events are defined in include/linux/vt.h. */
+
+#define NETLINK_URELEASE	0x0001	/* Unicast netlink socket released */
+
+/* Console keyboard events.
+ * Note: KBD_KEYCODE is always sent before KBD_UNBOUND_KEYCODE, KBD_UNICODE and
+ * KBD_KEYSYM. */
+#define KBD_KEYCODE		0x0001 /* Keyboard keycode, called before any other */
+#define KBD_UNBOUND_KEYCODE	0x0002 /* Keyboard keycode which is not bound to any other */
+#define KBD_UNICODE		0x0003 /* Keyboard unicode */
+#define KBD_KEYSYM		0x0004 /* Keyboard keysym */
+#define KBD_POST_KEYSYM		0x0005 /* Called after keyboard keysym interpretation */
+
+extern struct blocking_notifier_head reboot_notifier_list;
+
+#endif /* __KERNEL__ */
+#endif /* _LINUX_NOTIFIER_H */