From d20c219c7317843cec7f03eba15bfeae54f29654 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= Date: Fri, 18 Dec 2020 11:42:45 +0100 Subject: [PATCH] tty: new helper function tty_get_icount() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit For a given struct tty_struct this yields the corresponding statistics about sent and received characters (and some more) which is needed to implement an LED trigger for tty devices. The new function is then used to simplify tty_tiocgicount(). Reviewed-by: Pavel Machek Signed-off-by: Uwe Kleine-König Link: https://lore.kernel.org/r/20201218104246.591315-3-u.kleine-koenig@pengutronix.de Signed-off-by: Greg Kroah-Hartman --- drivers/tty/tty_io.c | 29 +++++++++++++++++++++++++---- include/linux/tty.h | 2 ++ 2 files changed, 27 insertions(+), 4 deletions(-) diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index 62ccd021102d..95ba028ef668 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -2488,15 +2488,36 @@ static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd, return tty->ops->tiocmset(tty, set, clear); } +/** + * tty_get_icount - get tty statistics + * @tty: tty device + * @icount: output parameter + * + * Gets a copy of the tty's icount statistics. + * + * Locking: none (up to the driver) + */ +int tty_get_icount(struct tty_struct *tty, + struct serial_icounter_struct *icount) +{ + memset(icount, 0, sizeof(*icount)); + + if (tty->ops->get_icount) + return tty->ops->get_icount(tty, icount); + else + return -EINVAL; +} +EXPORT_SYMBOL_GPL(tty_get_icount); + static int tty_tiocgicount(struct tty_struct *tty, void __user *arg) { - int retval = -EINVAL; struct serial_icounter_struct icount; - memset(&icount, 0, sizeof(icount)); - if (tty->ops->get_icount) - retval = tty->ops->get_icount(tty, &icount); + int retval; + + retval = tty_get_icount(tty, &icount); if (retval != 0) return retval; + if (copy_to_user(arg, &icount, sizeof(icount))) return -EFAULT; return 0; diff --git a/include/linux/tty.h b/include/linux/tty.h index df707a5abfac..12be8b16cdef 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -500,6 +500,8 @@ extern void tty_unthrottle(struct tty_struct *tty); extern int tty_throttle_safe(struct tty_struct *tty); extern int tty_unthrottle_safe(struct tty_struct *tty); extern int tty_do_resize(struct tty_struct *tty, struct winsize *ws); +extern int tty_get_icount(struct tty_struct *tty, + struct serial_icounter_struct *icount); extern int is_current_pgrp_orphaned(void); extern void tty_hangup(struct tty_struct *tty); extern void tty_vhangup(struct tty_struct *tty);