diff options
| author | Peter Hurley <peter@hurleysoftware.com> | 2013-06-15 07:28:28 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-06-17 12:55:11 -0700 |
| commit | f6c8dbe6e50c6e5121d7b6644718207daa008221 (patch) | |
| tree | f7200d98ecaa899fb2c83d6b58b88a20b302f936 /drivers/tty/tty_io.c | |
| parent | a630fbfbb1beeffc5bbe542a7986bf2068874633 (diff) | |
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>
Diffstat (limited to 'drivers/tty/tty_io.c')
| -rw-r--r-- | drivers/tty/tty_io.c | 17 |
1 files changed, 9 insertions, 8 deletions
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index 6464029e4860..bd88007fa6ea 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -2138,6 +2138,7 @@ static unsigned int tty_poll(struct file *filp, poll_table *wait) static int __tty_fasync(int fd, struct file *filp, int on) { struct tty_struct *tty = file_tty(filp); + struct tty_ldisc *ldisc; unsigned long flags; int retval = 0; @@ -2148,11 +2149,17 @@ static int __tty_fasync(int fd, struct file *filp, int on) if (retval <= 0) goto out; + ldisc = tty_ldisc_ref(tty); + if (ldisc) { + if (ldisc->ops->fasync) + ldisc->ops->fasync(tty, on); + tty_ldisc_deref(ldisc); + } + if (on) { enum pid_type type; struct pid *pid; - if (!waitqueue_active(&tty->read_wait)) - tty->minimum_to_wake = 1; + spin_lock_irqsave(&tty->ctrl_lock, flags); if (tty->pgrp) { pid = tty->pgrp; @@ -2165,13 +2172,7 @@ static int __tty_fasync(int fd, struct file *filp, int on) spin_unlock_irqrestore(&tty->ctrl_lock, flags); retval = __f_setown(filp, pid, type, 0); put_pid(pid); - if (retval) - goto out; - } else { - if (!tty->fasync && !waitqueue_active(&tty->read_wait)) - tty->minimum_to_wake = N_TTY_BUF_SIZE; } - retval = 0; out: return retval; } |