n_tty: Encapsulate minimum_to_wake within N_TTY
minimum_to_wake is unique to N_TTY processing, and belongs in
per-ldisc data.
Add the ldisc method, ldisc_ops::fasync(), to notify line disciplines
when signal-driven I/O is enabled or disabled. When enabled for N_TTY
(by fcntl(F_SETFL, O_ASYNC)), blocking reader/polls will be woken
for any readable input. When disabled, blocking reader/polls are not
woken until the read buffer is full.
Canonical mode (L_ICANON(tty), n_tty_data::icanon) is not affected by
the minimum_to_wake setting.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/include/linux/tty_ldisc.h b/include/linux/tty_ldisc.h
index 7b24bbd..a1b0489 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.
@@ -189,6 +194,7 @@
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;