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| author | Peter Hurley <peter@hurleysoftware.com> | 2013-06-15 09:14:31 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-07-23 16:43:02 -0700 |
| commit | d8c1f929aa8164cd8eaa830068d2fa3159c0764a (patch) | |
| tree | 1371cfe90fffdcb7115b39c77e0f729c109efc69 /drivers/tty/n_tty.c | |
| parent | fb7aa03db605e4f0b9a62cd4c77177c2596edd95 (diff) | |
| download | lwn-d8c1f929aa8164cd8eaa830068d2fa3159c0764a.tar.gz lwn-d8c1f929aa8164cd8eaa830068d2fa3159c0764a.zip | |
tty: Only guarantee termios read safety for throttle/unthrottle
No tty driver modifies termios during throttle() or unthrottle().
Therefore, only read safety is required.
However, tty_throttle_safe and tty_unthrottle_safe must still be
mutually exclusive; introduce throttle_mutex for that purpose.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/n_tty.c')
| -rw-r--r-- | drivers/tty/n_tty.c | 4 |
1 files changed, 0 insertions, 4 deletions
diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c index d0c8805d8131..b78ee464bd09 100644 --- a/drivers/tty/n_tty.c +++ b/drivers/tty/n_tty.c @@ -1518,9 +1518,7 @@ static void __receive_buf(struct tty_struct *tty, const unsigned char *cp, tty_set_flow_change(tty, TTY_THROTTLE_SAFE); if (receive_room(tty) >= TTY_THRESHOLD_THROTTLE) break; - up_read(&tty->termios_rwsem); throttled = tty_throttle_safe(tty); - down_read(&tty->termios_rwsem); if (!throttled) break; } @@ -2086,9 +2084,7 @@ do_it_again: if (!tty->count) break; n_tty_set_room(tty); - up_read(&tty->termios_rwsem); unthrottled = tty_unthrottle_safe(tty); - down_read(&tty->termios_rwsem); if (!unthrottled) break; } |