From fdfb719e93b55a50f90da2059dc450e7c0c48e8f Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Sun, 10 Jan 2016 22:40:54 -0800 Subject: [PATCH] tty: Remove chars_in_buffer() line discipline method The chars_in_buffer() line discipline method serves no functional purpose, other than as a (dubious) debugging aid for mostly bit-rotting drivers. Despite being documented as an optional method, every caller is unconditionally executed (although conditionally compiled). Furthermore, direct tty->ldisc access without an ldisc ref is unsafe. Lastly, N_TTY's chars_in_buffer() has warned of removal since 3.12. Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman --- Documentation/serial/tty.txt | 3 --- drivers/tty/amiserial.c | 6 ++---- drivers/tty/cyclades.c | 8 ++++---- drivers/tty/n_gsm.c | 16 ---------------- drivers/tty/n_tty.c | 23 ----------------------- drivers/tty/rocket.c | 6 ++---- drivers/tty/serial/crisv10.c | 12 +++++------- include/linux/tty_ldisc.h | 7 ------- 8 files changed, 13 insertions(+), 68 deletions(-) diff --git a/Documentation/serial/tty.txt b/Documentation/serial/tty.txt index bc3842dc323a..798cba82c762 100644 --- a/Documentation/serial/tty.txt +++ b/Documentation/serial/tty.txt @@ -72,9 +72,6 @@ flush_buffer() - (optional) May be called at any point between open and close, and instructs the line discipline to empty its input buffer. -chars_in_buffer() - (optional) Report the number of bytes in the input - buffer. - set_termios() - (optional) Called on termios structure changes. The caller passes the old termios data and the current data is in the tty. Called under the diff --git a/drivers/tty/amiserial.c b/drivers/tty/amiserial.c index 2caaf5a2516d..6ba5681b6385 100644 --- a/drivers/tty/amiserial.c +++ b/drivers/tty/amiserial.c @@ -965,8 +965,7 @@ static void rs_throttle(struct tty_struct * tty) struct serial_state *info = tty->driver_data; unsigned long flags; #ifdef SERIAL_DEBUG_THROTTLE - printk("throttle %s: %d....\n", tty_name(tty), - tty->ldisc.chars_in_buffer(tty)); + printk("throttle %s ....\n", tty_name(tty)); #endif if (serial_paranoia_check(info, tty->name, "rs_throttle")) @@ -988,8 +987,7 @@ static void rs_unthrottle(struct tty_struct * tty) struct serial_state *info = tty->driver_data; unsigned long flags; #ifdef SERIAL_DEBUG_THROTTLE - printk("unthrottle %s: %d....\n", tty_name(tty), - tty->ldisc.chars_in_buffer(tty)); + printk("unthrottle %s ....\n", tty_name(tty)); #endif if (serial_paranoia_check(info, tty->name, "rs_unthrottle")) diff --git a/drivers/tty/cyclades.c b/drivers/tty/cyclades.c index abbed201dc74..a48e7e66b970 100644 --- a/drivers/tty/cyclades.c +++ b/drivers/tty/cyclades.c @@ -2852,8 +2852,8 @@ static void cy_throttle(struct tty_struct *tty) unsigned long flags; #ifdef CY_DEBUG_THROTTLE - printk(KERN_DEBUG "cyc:throttle %s: %ld...ttyC%d\n", tty_name(tty), - tty->ldisc.chars_in_buffer(tty), info->line); + printk(KERN_DEBUG "cyc:throttle %s ...ttyC%d\n", tty_name(tty), + info->line); #endif if (serial_paranoia_check(info, tty->name, "cy_throttle")) @@ -2891,8 +2891,8 @@ static void cy_unthrottle(struct tty_struct *tty) unsigned long flags; #ifdef CY_DEBUG_THROTTLE - printk(KERN_DEBUG "cyc:unthrottle %s: %ld...ttyC%d\n", - tty_name(tty), tty_chars_in_buffer(tty), info->line); + printk(KERN_DEBUG "cyc:unthrottle %s ...ttyC%d\n", + tty_name(tty), info->line); #endif if (serial_paranoia_check(info, tty->name, "cy_unthrottle")) diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c index c3fe026d3168..e3cc27749344 100644 --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -2303,21 +2303,6 @@ static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp, /* If clogged call tty_throttle(tty); */ } -/** - * gsmld_chars_in_buffer - report available bytes - * @tty: tty device - * - * Report the number of characters buffered to be delivered to user - * at this instant in time. - * - * Locking: gsm lock - */ - -static ssize_t gsmld_chars_in_buffer(struct tty_struct *tty) -{ - return 0; -} - /** * gsmld_flush_buffer - clean input queue * @tty: terminal device @@ -2830,7 +2815,6 @@ static struct tty_ldisc_ops tty_ldisc_packet = { .open = gsmld_open, .close = gsmld_close, .flush_buffer = gsmld_flush_buffer, - .chars_in_buffer = gsmld_chars_in_buffer, .read = gsmld_read, .write = gsmld_write, .ioctl = gsmld_ioctl, diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c index b280abaad91b..90eca2605fbf 100644 --- a/drivers/tty/n_tty.c +++ b/drivers/tty/n_tty.c @@ -380,28 +380,6 @@ static void n_tty_flush_buffer(struct tty_struct *tty) up_write(&tty->termios_rwsem); } -/** - * n_tty_chars_in_buffer - report available bytes - * @tty: tty device - * - * Report the number of characters buffered to be delivered to user - * at this instant in time. - * - * Locking: exclusive termios_rwsem - */ - -static ssize_t n_tty_chars_in_buffer(struct tty_struct *tty) -{ - ssize_t n; - - WARN_ONCE(1, "%s is deprecated and scheduled for removal.", __func__); - - down_write(&tty->termios_rwsem); - n = chars_in_buffer(tty); - up_write(&tty->termios_rwsem); - return n; -} - /** * is_utf8_continuation - utf8 multibyte check * @c: byte to check @@ -2525,7 +2503,6 @@ struct tty_ldisc_ops tty_ldisc_N_TTY = { .open = n_tty_open, .close = n_tty_close, .flush_buffer = n_tty_flush_buffer, - .chars_in_buffer = n_tty_chars_in_buffer, .read = n_tty_read, .write = n_tty_write, .ioctl = n_tty_ioctl, diff --git a/drivers/tty/rocket.c b/drivers/tty/rocket.c index 802eac7e561b..f624b93a237f 100644 --- a/drivers/tty/rocket.c +++ b/drivers/tty/rocket.c @@ -1360,8 +1360,7 @@ static void rp_throttle(struct tty_struct *tty) struct r_port *info = tty->driver_data; #ifdef ROCKET_DEBUG_THROTTLE - printk(KERN_INFO "throttle %s: %d....\n", tty->name, - tty->ldisc.chars_in_buffer(tty)); + printk(KERN_INFO "throttle %s ....\n", tty->name); #endif if (rocket_paranoia_check(info, "rp_throttle")) @@ -1377,8 +1376,7 @@ static void rp_unthrottle(struct tty_struct *tty) { struct r_port *info = tty->driver_data; #ifdef ROCKET_DEBUG_THROTTLE - printk(KERN_INFO "unthrottle %s: %d....\n", tty->name, - tty->ldisc.chars_in_buffer(tty)); + printk(KERN_INFO "unthrottle %s ....\n", tty->name); #endif if (rocket_paranoia_check(info, "rp_unthrottle")) diff --git a/drivers/tty/serial/crisv10.c b/drivers/tty/serial/crisv10.c index f13f2ebd215b..e98aef797065 100644 --- a/drivers/tty/serial/crisv10.c +++ b/drivers/tty/serial/crisv10.c @@ -2968,7 +2968,7 @@ static int rs_raw_write(struct tty_struct *tty, local_save_flags(flags); DFLOW(DEBUG_LOG(info->line, "write count %i ", count)); - DFLOW(DEBUG_LOG(info->line, "ldisc %i\n", tty->ldisc.chars_in_buffer(tty))); + DFLOW(DEBUG_LOG(info->line, "ldisc\n")); /* The local_irq_disable/restore_flags pairs below are needed @@ -3161,10 +3161,9 @@ rs_throttle(struct tty_struct * tty) { struct e100_serial *info = (struct e100_serial *)tty->driver_data; #ifdef SERIAL_DEBUG_THROTTLE - printk("throttle %s: %lu....\n", tty_name(tty), - (unsigned long)tty->ldisc.chars_in_buffer(tty)); + printk("throttle %s ....\n", tty_name(tty)); #endif - DFLOW(DEBUG_LOG(info->line,"rs_throttle %lu\n", tty->ldisc.chars_in_buffer(tty))); + DFLOW(DEBUG_LOG(info->line,"rs_throttle\n")); /* Do RTS before XOFF since XOFF might take some time */ if (tty->termios.c_cflag & CRTSCTS) { @@ -3181,10 +3180,9 @@ rs_unthrottle(struct tty_struct * tty) { struct e100_serial *info = (struct e100_serial *)tty->driver_data; #ifdef SERIAL_DEBUG_THROTTLE - printk("unthrottle %s: %lu....\n", tty_name(tty), - (unsigned long)tty->ldisc.chars_in_buffer(tty)); + printk("unthrottle %s ....\n", tty_name(tty)); #endif - DFLOW(DEBUG_LOG(info->line,"rs_unthrottle ldisc %d\n", tty->ldisc.chars_in_buffer(tty))); + DFLOW(DEBUG_LOG(info->line,"rs_unthrottle ldisc\n")); DFLOW(DEBUG_LOG(info->line,"rs_unthrottle flip.count: %i\n", tty->flip.count)); /* Do RTS before XOFF since XOFF might take some time */ if (tty->termios.c_cflag & CRTSCTS) { diff --git a/include/linux/tty_ldisc.h b/include/linux/tty_ldisc.h index 00c9d688d7b7..6101ab8dc148 100644 --- a/include/linux/tty_ldisc.h +++ b/include/linux/tty_ldisc.h @@ -25,12 +25,6 @@ * buffers of any input characters it may have queued to be * delivered to the user mode process. * - * ssize_t (*chars_in_buffer)(struct tty_struct *tty); - * - * This function returns the number of input characters the line - * discipline may have queued up to be delivered to the user mode - * process. - * * ssize_t (*read)(struct tty_struct * tty, struct file * file, * unsigned char * buf, size_t nr); * @@ -188,7 +182,6 @@ struct tty_ldisc_ops { int (*open)(struct tty_struct *); void (*close)(struct tty_struct *); void (*flush_buffer)(struct tty_struct *tty); - ssize_t (*chars_in_buffer)(struct tty_struct *tty); ssize_t (*read)(struct tty_struct *tty, struct file *file, unsigned char __user *buf, size_t nr); ssize_t (*write)(struct tty_struct *tty, struct file *file, -- 2.20.1