Fedora kernel-2.6.17-1.2142_FC4 patched with stable patch-2.6.17.4-vs2.0.2-rc26.diff

[linux-2.6.git] / include / linux / notifier.h

diff --git a/include/linux/notifier.h b/include/linux/notifier.h
index 5937dd6..51dbab9 100644 (file)
--- a/include/linux/notifier.h
+++ b/include/linux/notifier.h
@@ -10,25 +10,107 @@
 #ifndef _LINUX_NOTIFIER_H
 #define _LINUX_NOTIFIER_H
 #include <linux/errno.h>
+#include <linux/mutex.h>
+#include <linux/rwsem.h>
 
-struct notifier_block
-{
-       int (*notifier_call)(struct notifier_block *self, unsigned long, void *);
+/*
+ * Notifier chains are of three 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.
+ *
+ * atomic_notifier_chain_register() may be called from an atomic context,
+ * but blocking_notifier_chain_register() must be called from a process
+ * context.  Ditto for the corresponding _unregister() routines.
+ *
+ * atomic_notifier_chain_unregister() and blocking_notifier_chain_unregister()
+ * _must not_ be called from within the call chain.
+ */
+
+struct notifier_block {
+       int (*notifier_call)(struct notifier_block *, unsigned long, void *);
        struct notifier_block *next;
        int priority;
 };
 
+struct atomic_notifier_head {
+       spinlock_t lock;
+       struct notifier_block *head;
+};
+
+struct blocking_notifier_head {
+       struct rw_semaphore rwsem;
+       struct notifier_block *head;
+};
+
+struct raw_notifier_head {
+       struct notifier_block *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)
+
+#define ATOMIC_NOTIFIER_INIT(name) {                           \
+               .lock = SPIN_LOCK_UNLOCKED,                     \
+               .head = NULL }
+#define BLOCKING_NOTIFIER_INIT(name) {                         \
+               .rwsem = __RWSEM_INITIALIZER((name).rwsem),     \
+               .head = NULL }
+#define RAW_NOTIFIER_INIT(name)        {                               \
+               .head = NULL }
+
+#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 __KERNEL__
 
-extern int notifier_chain_register(struct notifier_block **list, struct notifier_block *n);
-extern int notifier_chain_unregister(struct notifier_block **nl, struct notifier_block *n);
-extern int notifier_call_chain(struct notifier_block **n, unsigned long val, void *v);
+extern int atomic_notifier_chain_register(struct atomic_notifier_head *,
+               struct notifier_block *);
+extern int blocking_notifier_chain_register(struct blocking_notifier_head *,
+               struct notifier_block *);
+extern int raw_notifier_chain_register(struct raw_notifier_head *,
+               struct notifier_block *);
+
+extern int atomic_notifier_chain_unregister(struct atomic_notifier_head *,
+               struct notifier_block *);
+extern int blocking_notifier_chain_unregister(struct blocking_notifier_head *,
+               struct notifier_block *);
+extern int raw_notifier_chain_unregister(struct raw_notifier_head *,
+               struct notifier_block *);
+
+extern int atomic_notifier_call_chain(struct atomic_notifier_head *,
+               unsigned long val, void *v);
+extern int blocking_notifier_call_chain(struct blocking_notifier_head *,
+               unsigned long val, void *v);
+extern int raw_notifier_call_chain(struct raw_notifier_head *,
+               unsigned long val, void *v);
 
 #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      */
+#define NOTIFY_BAD             (NOTIFY_STOP_MASK|0x0002)
+                                               /* Bad/Veto action */
 /*
  * Clean way to return from the notifier and stop further calls.
  */