1 files changed, 52 insertions, 0 deletions

diff --git a/include/linux/tty_ldisc.h b/include/linux/tty_ldisc.h
index 58390c73df8b..a1b048999821 100644
--- a/include/linux/tty_ldisc.h
+++ b/include/linux/tty_ldisc.h
@@ -100,6 +100,11 @@
  *      seek to perform this action quickly but should wait until
  *      any pending driver I/O is completed.
  *
+ * void (*fasync)(struct tty_struct *, int on)
+ *
+ *      Notify line discipline when signal-driven I/O is enabled or
+ *      disabled.
+ *
  * void (*dcd_change)(struct tty_struct *tty, unsigned int status)
  *
  *      Tells the discipline that the DCD pin has changed its status.
@@ -110,6 +115,52 @@
 #include <linux/wait.h>
 #include <linux/wait.h>
 
+
+/*
+ * the semaphore definition
+ */
+struct ld_semaphore {
+        long                    count;
+        raw_spinlock_t          wait_lock;
+        unsigned int            wait_readers;
+        struct list_head        read_wait;
+        struct list_head        write_wait;
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+        struct lockdep_map      dep_map;
+#endif
+};
+
+extern void __init_ldsem(struct ld_semaphore *sem, const char *name,
+                         struct lock_class_key *key);
+
+#define init_ldsem(sem)                                         \
+do {                                                            \
+        static struct lock_class_key __key;                     \
+                                                                \
+        __init_ldsem((sem), #sem, &__key);                      \
+} while (0)
+
+
+extern int ldsem_down_read(struct ld_semaphore *sem, long timeout);
+extern int ldsem_down_read_trylock(struct ld_semaphore *sem);
+extern int ldsem_down_write(struct ld_semaphore *sem, long timeout);
+extern int ldsem_down_write_trylock(struct ld_semaphore *sem);
+extern void ldsem_up_read(struct ld_semaphore *sem);
+extern void ldsem_up_write(struct ld_semaphore *sem);
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+extern int ldsem_down_read_nested(struct ld_semaphore *sem, int subclass,
+                                  long timeout);
+extern int ldsem_down_write_nested(struct ld_semaphore *sem, int subclass,
+                                   long timeout);
+#else
+# define ldsem_down_read_nested(sem, subclass, timeout)         \
+                ldsem_down_read(sem, timeout)
+# define ldsem_down_write_nested(sem, subclass, timeout)        \
+                ldsem_down_write(sem, timeout)
+#endif
+
+
 struct tty_ldisc_ops {
         int     magic;
         char    *name;
@@ -143,6 +194,7 @@ struct tty_ldisc_ops {
                                char *fp, int count);
         void    (*write_wakeup)(struct tty_struct *);
         void    (*dcd_change)(struct tty_struct *, unsigned int);
+        void    (*fasync)(struct tty_struct *tty, int on);
 
         struct  module *owner;